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by BojanaL at 09-30-2012, 05:24 AM
5 comments
This article explains what exactly Stem Cells are, how they function and their applications.
Almost all multicellular organisms are developed from the fertilized egg. No matter if you are a plant, worm, frog or human, principal is the same. After sperm and egg merge – a zygote is formed. Diploid cell divides, leading to the next stage - embryo formation. Subsequent gigantic morphological changes can last more or less (species specific) until new organism is fully developed and ready to be born.
Cell division is necessary to increase the number of cells that will form different tissues and organs. Approximate number of cells in adult human body is 100 trillion forming 200 different cell types. It’s hard to imagine that all cells share the same ancestor considering how different they look at the end. Despite intense divisions cells are undergoing, they remain the same with intact genetic material derived from their parents. Position cell hold in the early stage of embryonic development (inside three germ’s layer) will determine its future destiny. Cells lying in the endoderm will become part of the digestive or respiratory system; cells in mesoderm – part of the muscle or bones and cells in ectoderm – part of nervous or integumentary system. Cell potency is crucial factor for differentiation processes that are leading to the new organism formation. Totipotent cell is the one able to differentiate into every kind of cells that are present in developed multicellular organism. Pluripotent cell still have high potency and can give a rise to a lot of different cell types but can’t produce extraembryonic tissue. Multipotent cell have ability to form minor number of cell types and oligopotent cell even less. With each new division, cell is becoming more differentiated and less potent. Modifications in genetic expression are controlling whole process of cell division and their specialization.
Once cell is differentiated, it becomes ready to serve its purpose. Lifespan of the cells is determined by the role they play. Taste receptors are living 10-15 days; skin cells one month, red blood cells around 3 months, muscle cells almost 15 years and nervous cells are in our body for a lifetime. Multipotent cells are replacing old cells or cells that are destroyed accidently (traumatic events like broken bone or burned skin). All “replacements” in our body are made by mesenchymal, adipose, endothelial or dental pulp stem cells.
Ability of cells to divide and differentiate as necessary was well know fact even at the beginning of the last century, but technology had to develop more to enable us to exploit that characteristic completely.
Martin Evans is a scientist responsible for isolating embryonic cell our of the mouse embryo and for gene targeting technique development. Knockout mouse is animal lacking one or more genes and it’s used for experiments where specific roles of the genes are investigated. He won a Nobel Prize for the contribution to the medicine and physiology.
Besides being useful for genetic experiments, stem cells become inevitable in therapy of various illnesses. The most used and famous stem cell associated therapy is bone marrow transplantation. It’s used for treatment of leukemia and lymphoma. Other promising therapies included brain and spinal cord injuries, intra cranial tumors, myocardial infarction, baldness, blindness and visual impairments, deafness, diabetes, neural and birth defects, wound healing, infertility…
Stem cells could be used for the animal treatments and they are especially effective for cardiac and musculoskeletal disorders.
Since stem cell therapy is one of the most promising future treatments, people are able to isolate and cryopreserve stem cells of their offspring by collecting samples of amniotic fluid (amniocentesis) during the pregnancy or out of the umbilical cord blood after the birth. Using specific techniques those cells are frozen and cryopreserved by liquid nitrogen. That way, cells are kept alive and ready for use the minute they are needed.
Another way to produce necessary amount of stem cells is to multiply them artificially. Those techniques are used in regenerative medicine, where cells, tissues or organs are replaced with laboratory grown implants. This type of healing can be faster and safer than waiting for organ donation. Also, that could solve the problem of immune response that is happening every time foreign organ is implanted. If patient himself donates cells for laboratory cultivation, transplant rejection will be avoided as body will recognize replaced tissue/organ as his own.
Therapeutic application of the stem cells is endless. Those are our cells and they “know” how to repair what need to be repaired once they are in the hotspot of the disease. Make sure to preserve your offspring’s stem cells – you never know when you going to need them.
Almost all multicellular organisms are developed from the fertilized egg. No matter if you are a plant, worm, frog or human, principal is the same. After sperm and egg merge – a zygote is formed. Diploid cell divides, leading to the next stage - embryo formation. Subsequent gigantic morphological changes can last more or less (species specific) until new organism is fully developed and ready to be born.
Cell division is necessary to increase the number of cells that will form different tissues and organs. Approximate number of cells in adult human body is 100 trillion forming 200 different cell types. It’s hard to imagine that all cells share the same ancestor considering how different they look at the end. Despite intense divisions cells are undergoing, they remain the same with intact genetic material derived from their parents. Position cell hold in the early stage of embryonic development (inside three germ’s layer) will determine its future destiny. Cells lying in the endoderm will become part of the digestive or respiratory system; cells in mesoderm – part of the muscle or bones and cells in ectoderm – part of nervous or integumentary system. Cell potency is crucial factor for differentiation processes that are leading to the new organism formation. Totipotent cell is the one able to differentiate into every kind of cells that are present in developed multicellular organism. Pluripotent cell still have high potency and can give a rise to a lot of different cell types but can’t produce extraembryonic tissue. Multipotent cell have ability to form minor number of cell types and oligopotent cell even less. With each new division, cell is becoming more differentiated and less potent. Modifications in genetic expression are controlling whole process of cell division and their specialization.
Once cell is differentiated, it becomes ready to serve its purpose. Lifespan of the cells is determined by the role they play. Taste receptors are living 10-15 days; skin cells one month, red blood cells around 3 months, muscle cells almost 15 years and nervous cells are in our body for a lifetime. Multipotent cells are replacing old cells or cells that are destroyed accidently (traumatic events like broken bone or burned skin). All “replacements” in our body are made by mesenchymal, adipose, endothelial or dental pulp stem cells.
Ability of cells to divide and differentiate as necessary was well know fact even at the beginning of the last century, but technology had to develop more to enable us to exploit that characteristic completely.
Martin Evans is a scientist responsible for isolating embryonic cell our of the mouse embryo and for gene targeting technique development. Knockout mouse is animal lacking one or more genes and it’s used for experiments where specific roles of the genes are investigated. He won a Nobel Prize for the contribution to the medicine and physiology.
Besides being useful for genetic experiments, stem cells become inevitable in therapy of various illnesses. The most used and famous stem cell associated therapy is bone marrow transplantation. It’s used for treatment of leukemia and lymphoma. Other promising therapies included brain and spinal cord injuries, intra cranial tumors, myocardial infarction, baldness, blindness and visual impairments, deafness, diabetes, neural and birth defects, wound healing, infertility…
Stem cells could be used for the animal treatments and they are especially effective for cardiac and musculoskeletal disorders.
Since stem cell therapy is one of the most promising future treatments, people are able to isolate and cryopreserve stem cells of their offspring by collecting samples of amniotic fluid (amniocentesis) during the pregnancy or out of the umbilical cord blood after the birth. Using specific techniques those cells are frozen and cryopreserved by liquid nitrogen. That way, cells are kept alive and ready for use the minute they are needed.
Another way to produce necessary amount of stem cells is to multiply them artificially. Those techniques are used in regenerative medicine, where cells, tissues or organs are replaced with laboratory grown implants. This type of healing can be faster and safer than waiting for organ donation. Also, that could solve the problem of immune response that is happening every time foreign organ is implanted. If patient himself donates cells for laboratory cultivation, transplant rejection will be avoided as body will recognize replaced tissue/organ as his own.
Therapeutic application of the stem cells is endless. Those are our cells and they “know” how to repair what need to be repaired once they are in the hotspot of the disease. Make sure to preserve your offspring’s stem cells – you never know when you going to need them.
by Ishani7 at 09-30-2012, 04:47 AM
2 comments
Plants and animals generally produce toxins naturally as defense mechanisms to protect them from environmental stresses and predators. Plant products or animals with a higher amount of toxins are not used as food. For an instance, though castor seeds contain high amount of fat, but it is not used as a food as it contains a toxin called as Ricin. However, there can be chemicals that can cause various abnormal conditions to humans in minute quantities. These harmful chemicals can be categorized as mutagens, teratogens, antinutrients, carcinogens, physiological irritants. These chemicals can cause negative impacts on health in long term ingestion. Effects from these chemicals can be enhanced when ingested by people with metabolic errors which are genetically inherited and when large quantities are ingested.
Lactose is a disaccharide present in milk that is known as the milk sugar. Some people who have difficulties in digesting lactose develop lactose intolerance which results from breaking down of lactose by intestinal micro flora producing acid and gas. Lactose free milk is commercially available to such people. Fructose intolerance results from incapability to digest fructose which is less common to lactose intolerance. People with Celiac disease cannot digest gluten which is a major constituent in wheat. Gluten causes internal hemorrhages producing bloody stools. Galactocemia, Phenylketonuria, Hemochromatosis, Wilson’s disease are some other diseases results in metabolism errors.
Food allergy is an immunological response caused when a foreign body is entered into the body and the immune system produce antibodies. In this situation, body recognizes the food constituent as a foreign body. Major allergenic food groups include milk, wheat, nuts, egg, meat/fish/shellfish, soy and peanuts. Prominently, the proteins in these foods are responsible for allergic reactions.
Protease inhibitors are a common type of plant toxins which are rich in legumes and cereals. By inhibiting these enzymes, these toxins make the specific proteins less available. Most of these protease inhibitors are heat labile. In contrast, some of these enzyme inhibitors are known to suppress tumor growth. Hemagglutinins and lectins present in high amounts in legumes and grains. Lectins are known to promote blood clotting, damage gut epithelium leading to local hemorrhages and kidney damage. Lectins also possess anticarcinogenic properties. Saponins found in soybean, spinach are another toxin with hemolytic effect. Vicine and covicine present in fava beans lead to a condition called favism which is developed in oversensitive people. This oversensitivity hereditary and controlled by a sex linked gene commonly occurs in Afro-Americans, Africans. Skeletal abnormalities results from altered metabolism in connective tissue due to Lathyrogens present in sweet pea, which are chemically unusual amino acids. Glucosinolates found in vegetables of Cruciferacea family promotes hypo and hyper thyroidism conditions.
Cyanogenic glucosides are another group of toxins which yields Hydrogen cyanide upon exposure to gastric acids and plant enzymes. Hydrogen cyanide is a potent respiratory inhibitor and arrests the cellular respiration very efficiently. Cyanogenic glucosides are commonly found in sorghum, almonds, cassava, lima beans, peach seeds etc. This is a major problem in countries where cassava is the staple food. Cyanide can potentially destroy the β cells of pancreas. Bitter varieties of cassava contain higher amount of these toxins.
Phytic acid is a naturally present metal binder which reduces the availability of metal ions. Phytic acid is a simple sugar with many phosphate groups attached. These phosphate groups can bind to multivalent cations. When metal ions are bound with phytates, they become unavailable. Phytic acid is present in wheat. In countries that consume wheat in large quantities, fertility of males is reduced as Zink ions are made unavailable.
Germinating potatoes contain eyes with greenish areas which contain certain amount of solarine. Solarine is a carcinogen. Mushrooms are well known for food intoxications. Mushrooms like Amanita contains deadly toxins called Amanita toxins.
Apart from plant toxins, fish toxins are important. Paralytic shellfish poisoning results from a toxin produced by dinoflagellates belongs to Saxitoxins. This is a heat stable neurotoxin which blocks the entry of Sodium ions into nerve cells. Diarrheal shellfish poisoning is commonly seen in Europe, Latin America and Japan developed as a result of Okadaic acid from dinoflagellates. Ciguatera toxicity is most injurious from public health and economic stand point. The toxicity is due to toxins produced by a marine algae; Gambierdiscus toxicus. This fat soluble toxin is heat stable and causes paralysis and death.
These naturally present toxins are difficult to eliminate. It is important to destroy the possible toxins by using proper cooking methods.
Lactose is a disaccharide present in milk that is known as the milk sugar. Some people who have difficulties in digesting lactose develop lactose intolerance which results from breaking down of lactose by intestinal micro flora producing acid and gas. Lactose free milk is commercially available to such people. Fructose intolerance results from incapability to digest fructose which is less common to lactose intolerance. People with Celiac disease cannot digest gluten which is a major constituent in wheat. Gluten causes internal hemorrhages producing bloody stools. Galactocemia, Phenylketonuria, Hemochromatosis, Wilson’s disease are some other diseases results in metabolism errors.
Food allergy is an immunological response caused when a foreign body is entered into the body and the immune system produce antibodies. In this situation, body recognizes the food constituent as a foreign body. Major allergenic food groups include milk, wheat, nuts, egg, meat/fish/shellfish, soy and peanuts. Prominently, the proteins in these foods are responsible for allergic reactions.
Protease inhibitors are a common type of plant toxins which are rich in legumes and cereals. By inhibiting these enzymes, these toxins make the specific proteins less available. Most of these protease inhibitors are heat labile. In contrast, some of these enzyme inhibitors are known to suppress tumor growth. Hemagglutinins and lectins present in high amounts in legumes and grains. Lectins are known to promote blood clotting, damage gut epithelium leading to local hemorrhages and kidney damage. Lectins also possess anticarcinogenic properties. Saponins found in soybean, spinach are another toxin with hemolytic effect. Vicine and covicine present in fava beans lead to a condition called favism which is developed in oversensitive people. This oversensitivity hereditary and controlled by a sex linked gene commonly occurs in Afro-Americans, Africans. Skeletal abnormalities results from altered metabolism in connective tissue due to Lathyrogens present in sweet pea, which are chemically unusual amino acids. Glucosinolates found in vegetables of Cruciferacea family promotes hypo and hyper thyroidism conditions.
Cyanogenic glucosides are another group of toxins which yields Hydrogen cyanide upon exposure to gastric acids and plant enzymes. Hydrogen cyanide is a potent respiratory inhibitor and arrests the cellular respiration very efficiently. Cyanogenic glucosides are commonly found in sorghum, almonds, cassava, lima beans, peach seeds etc. This is a major problem in countries where cassava is the staple food. Cyanide can potentially destroy the β cells of pancreas. Bitter varieties of cassava contain higher amount of these toxins.
Phytic acid is a naturally present metal binder which reduces the availability of metal ions. Phytic acid is a simple sugar with many phosphate groups attached. These phosphate groups can bind to multivalent cations. When metal ions are bound with phytates, they become unavailable. Phytic acid is present in wheat. In countries that consume wheat in large quantities, fertility of males is reduced as Zink ions are made unavailable.
Germinating potatoes contain eyes with greenish areas which contain certain amount of solarine. Solarine is a carcinogen. Mushrooms are well known for food intoxications. Mushrooms like Amanita contains deadly toxins called Amanita toxins.
Apart from plant toxins, fish toxins are important. Paralytic shellfish poisoning results from a toxin produced by dinoflagellates belongs to Saxitoxins. This is a heat stable neurotoxin which blocks the entry of Sodium ions into nerve cells. Diarrheal shellfish poisoning is commonly seen in Europe, Latin America and Japan developed as a result of Okadaic acid from dinoflagellates. Ciguatera toxicity is most injurious from public health and economic stand point. The toxicity is due to toxins produced by a marine algae; Gambierdiscus toxicus. This fat soluble toxin is heat stable and causes paralysis and death.
These naturally present toxins are difficult to eliminate. It is important to destroy the possible toxins by using proper cooking methods.
by Ishani7 at 09-30-2012, 02:43 AM
0 comments
Persistent green colour in our daily diet is an indication that necessary micronutrients and macronutrients are supplemented with the food. Green colour in vegetables is due to the presence of Chlorophyll pigments. This is the universal pigment that carries out photosynthesis in plants, algae and photosynthetic bacteria. Chlorophyll exists in two forms: "Chlorophyll A" and "Chlorophyll B".
Chlorophyll A (C55H72MgN4O5) is a complex molecule with a molecular weight of 893.49. It is a tetrapyrole structure consisting of phytol, a higher alcohol and a Mg2+ ion chelated in the centre. Chlorophyll A content is more in green food items. However, preservation of green colour is important in food industry. Persistence of natural green colour in food is an indication of a healthy food item to consumers.
If we consider the green colour in different food items such as dehydrated vegetables, green tea leaves, green chili sauce, porridge, olives, fermented products; there is a clear cut difference in the green shade. This results from various processing conditions used in cooking or preserving of the food. This green pigment which is naturally present is converted to various forms when exposed to different conditions. Concentration of Chlorophyll present, presence of phenolic compound which enhances enzymatic browning, entrapment of the pigment within cellulose, amount of acids present are also key factor for determining the specific shade of green apart from structural changes that occur in chlorophyll.
Chlorophyll is naturally present linked to a lipoprotein which protects it from acid digestion. These organic acids present in cell vacuoles are denatured during food processing. Phytol which is a higher alcohol in Chlorophyll makes the Chlorophyll molecule insoluble in water. It is observable when green leaves are put into water, water doesn’t become green. But when the leaves are macerated, it turns green. In maceration of green leaves when making porridge, green pigment and the Chlorophyllase enzyme present inside the cell comes out. Chlorophyllase enzyme removes the phytol group from the pigment producing Chlorophyllide A, which is water soluble. Chlorophyllide A is further degraded into purpurins in the presence of acids and Oxygen which results in loss of green colour. Chlorophyllide A is converted to Pheophorbide A in the presence of acids. Pheophorbide A is olive brown in colour. This also can be converted to Purpurins by oxidation.
Many food processing methods, involves heating the vegetables. The degree of heating differs when steaming, frying, tempering etc. This affects the green colour of the food. When heating green vegetables, pheophytinization can take place in which the Mg2+ ions are replaced by H+ ions producing pheophytin A from Chlorophyll A. Pheophytin A can be converted to purpurins and Pheophorbide under different conditions. In food processing, using high temperatures for a short time is effective in preserving green colour. Blanching is a good method to preserve green colour as it inactivates the enzyme system of the green vegetables. In drying, sun drying is not effective in retaining green colour. It enhances photochemical oxidation of Chlorophyll pigment.
Amount of phenolic compounds in vegetables indirectly affect the shade of green in food. These phenolic compounds are the substrate to enzymatic browning reactions. Product of enzymatic browning is a brown colour pigment known as melanin. This brown product masks the green colour that is naturally present. This occurs when the vegetables are cut, macerated, damaged which expose internal tissues to Oxygen.
Photochemical oxidation also results in change of natural green colour present in vegetables. This plays a significant role in selecting of packaging materials for marketing of green vegetables. Higher Oxygen concentration and light increase the rate of photochemical oxidation. Therefore, it’s a must to select packaging material with higher Oxygen and light barrier properties.
The labels on the food products may indicate that additives are not used. But the reality is, it is not possible to retain green colour without additives. Especially in acidic food products like sauce, natural pigments cannot be preserved without using preservatives.
However, in terms of health; Chlorophyll plays a vital role. Recent research focuses on the ability of Chlorophyll to retard cancer by reducing the damage to DNA caused by mycotoxins. It is also known to reduce stress, anemia, fatigue and speed up wound healing.
Chlorophyll A (C55H72MgN4O5) is a complex molecule with a molecular weight of 893.49. It is a tetrapyrole structure consisting of phytol, a higher alcohol and a Mg2+ ion chelated in the centre. Chlorophyll A content is more in green food items. However, preservation of green colour is important in food industry. Persistence of natural green colour in food is an indication of a healthy food item to consumers.
If we consider the green colour in different food items such as dehydrated vegetables, green tea leaves, green chili sauce, porridge, olives, fermented products; there is a clear cut difference in the green shade. This results from various processing conditions used in cooking or preserving of the food. This green pigment which is naturally present is converted to various forms when exposed to different conditions. Concentration of Chlorophyll present, presence of phenolic compound which enhances enzymatic browning, entrapment of the pigment within cellulose, amount of acids present are also key factor for determining the specific shade of green apart from structural changes that occur in chlorophyll.
Chlorophyll is naturally present linked to a lipoprotein which protects it from acid digestion. These organic acids present in cell vacuoles are denatured during food processing. Phytol which is a higher alcohol in Chlorophyll makes the Chlorophyll molecule insoluble in water. It is observable when green leaves are put into water, water doesn’t become green. But when the leaves are macerated, it turns green. In maceration of green leaves when making porridge, green pigment and the Chlorophyllase enzyme present inside the cell comes out. Chlorophyllase enzyme removes the phytol group from the pigment producing Chlorophyllide A, which is water soluble. Chlorophyllide A is further degraded into purpurins in the presence of acids and Oxygen which results in loss of green colour. Chlorophyllide A is converted to Pheophorbide A in the presence of acids. Pheophorbide A is olive brown in colour. This also can be converted to Purpurins by oxidation.
Many food processing methods, involves heating the vegetables. The degree of heating differs when steaming, frying, tempering etc. This affects the green colour of the food. When heating green vegetables, pheophytinization can take place in which the Mg2+ ions are replaced by H+ ions producing pheophytin A from Chlorophyll A. Pheophytin A can be converted to purpurins and Pheophorbide under different conditions. In food processing, using high temperatures for a short time is effective in preserving green colour. Blanching is a good method to preserve green colour as it inactivates the enzyme system of the green vegetables. In drying, sun drying is not effective in retaining green colour. It enhances photochemical oxidation of Chlorophyll pigment.
Amount of phenolic compounds in vegetables indirectly affect the shade of green in food. These phenolic compounds are the substrate to enzymatic browning reactions. Product of enzymatic browning is a brown colour pigment known as melanin. This brown product masks the green colour that is naturally present. This occurs when the vegetables are cut, macerated, damaged which expose internal tissues to Oxygen.
Photochemical oxidation also results in change of natural green colour present in vegetables. This plays a significant role in selecting of packaging materials for marketing of green vegetables. Higher Oxygen concentration and light increase the rate of photochemical oxidation. Therefore, it’s a must to select packaging material with higher Oxygen and light barrier properties.
The labels on the food products may indicate that additives are not used. But the reality is, it is not possible to retain green colour without additives. Especially in acidic food products like sauce, natural pigments cannot be preserved without using preservatives.
However, in terms of health; Chlorophyll plays a vital role. Recent research focuses on the ability of Chlorophyll to retard cancer by reducing the damage to DNA caused by mycotoxins. It is also known to reduce stress, anemia, fatigue and speed up wound healing.
by BojanaL at 09-29-2012, 09:39 PM
0 comments
Human population expanded greatly in the last two centuries thanks to technology that makes us healthier, well fed, pleasantly accommodated….
Even thought man already inhabited incredible portion of the planet, he still needs to conquer some more in order to get a room for all of us. Planet size is unchangeable as well as the amount of natural resources we could use. That means that some of us will suffer inevitable consequences for being so numerous. Millions of people all over the globe are starving. Uncultivated land, unpredictable weather conditions, droughts, floods… are to be blamed. If land and weather are satisfying, than weeds and insects are our main concerns. What seemed like good solution for the food crisis came to the scene at the beginning of the ’80 in the past century.
Genetic engineering offered plenty solutions. Diversity of living creatures and their characteristics is inconceivable. Whole genome sequencing allowed us to find and extract genes that could help and improve agriculture a lot. By inserting a couple of new genes we modified plant enough to become stronger, resistant to a pesticides, taught weather conditions or one that could provide more harvest. Antibiotic resistant tobacco, herbicide resistant soybean, corn and cotton, delayed ripening tomato…are the most famous examples of genetically modified food today. Can they solve the question of world hunger? Are they safe? Eco-friendly?
What are the main obstacles with breading and consuming genetically modified organisms? Well, for the start, every time man decided to repair the nature, he ended up with one thing fixed and three other broken. The reason is fragility of natural balance, where every species have certain place and function. We are all deeply connected. Most things in nature resemble chain reaction – if you change just one hoop the rest of the chain will suffer the consequences. Introducing genetically modified (GM) and fortified plant to some area means those “weak” natural plants doesn’t stand a chance. Monocultures are winning the battle with natural diversity. This kind of planting has a lot of other things to be worried about, besides erasing numerous plants from our environment. Herbicide resisting plants are designed to withstand a huge amount of aggressive chemicals that will destroy insects and weeds. Some of those chemicals will be washed away by rain, but most of them will stay on the plant after harvest. Plants will undergo technological modifications before reaching the market (and your table), but you can be sure that beside vitamins and essential nutrients they will enrich your meal with herbicide/pesticide residues. What happens next is that weeds and insects are becoming resistant to the pesticide used so other chemicals had to be manufactured, new transgenic plant created…- vicious circle. Chemicals can harm our health but they are not the only problem in this story. Transgenic plants can induce adverse effect on their own. Experiment with Brazilian nut and bean is perfect example. Nut allergy is one of the most common food allergies in human population. Genes from Brazilian nut were inserted in the bean and transgenic plant was given to the rats. Even thought rats were eating bean, nut allergy was initiated. Few cases proved that transgenic allergy can be induced even if animal is not allergic to plants when they are given separately. And now let’s mix effects of both pesticide and genetic modification in one experiment. French researchers used transgenic corn combined with pesticide residues and experimented for 2 years on 200 rats. Animals were fed with transgenic corn from day one. Blood test (biochemistry, hormone levels…) and histological examinations were performed. Results were devastating. 97% of females developed mammary tumors, while renal tumors dominated in males. In both cases, altered hormonal levels initiated tumor formation. Pesticide affected liver, kidney, embryo… exerting typical toxic effects. Taken together, they shortened animal’s life dramatically. When those two were compared, GM food induced more severe pathologies and killed more animals showing that transgenesis itself could be more harmful then chemical poising.
This is not the first experiment showing how dangerous GM food could be, but it’s still manufactured and sold thought out the world. GM seed manufacturers are demanding a signed promise that it’s not going to be used for experimental purposes. What is that telling you? We don't know how genetically modified food affects human health. As with so many other things - time will show.
Even thought man already inhabited incredible portion of the planet, he still needs to conquer some more in order to get a room for all of us. Planet size is unchangeable as well as the amount of natural resources we could use. That means that some of us will suffer inevitable consequences for being so numerous. Millions of people all over the globe are starving. Uncultivated land, unpredictable weather conditions, droughts, floods… are to be blamed. If land and weather are satisfying, than weeds and insects are our main concerns. What seemed like good solution for the food crisis came to the scene at the beginning of the ’80 in the past century.
Genetic engineering offered plenty solutions. Diversity of living creatures and their characteristics is inconceivable. Whole genome sequencing allowed us to find and extract genes that could help and improve agriculture a lot. By inserting a couple of new genes we modified plant enough to become stronger, resistant to a pesticides, taught weather conditions or one that could provide more harvest. Antibiotic resistant tobacco, herbicide resistant soybean, corn and cotton, delayed ripening tomato…are the most famous examples of genetically modified food today. Can they solve the question of world hunger? Are they safe? Eco-friendly?
What are the main obstacles with breading and consuming genetically modified organisms? Well, for the start, every time man decided to repair the nature, he ended up with one thing fixed and three other broken. The reason is fragility of natural balance, where every species have certain place and function. We are all deeply connected. Most things in nature resemble chain reaction – if you change just one hoop the rest of the chain will suffer the consequences. Introducing genetically modified (GM) and fortified plant to some area means those “weak” natural plants doesn’t stand a chance. Monocultures are winning the battle with natural diversity. This kind of planting has a lot of other things to be worried about, besides erasing numerous plants from our environment. Herbicide resisting plants are designed to withstand a huge amount of aggressive chemicals that will destroy insects and weeds. Some of those chemicals will be washed away by rain, but most of them will stay on the plant after harvest. Plants will undergo technological modifications before reaching the market (and your table), but you can be sure that beside vitamins and essential nutrients they will enrich your meal with herbicide/pesticide residues. What happens next is that weeds and insects are becoming resistant to the pesticide used so other chemicals had to be manufactured, new transgenic plant created…- vicious circle. Chemicals can harm our health but they are not the only problem in this story. Transgenic plants can induce adverse effect on their own. Experiment with Brazilian nut and bean is perfect example. Nut allergy is one of the most common food allergies in human population. Genes from Brazilian nut were inserted in the bean and transgenic plant was given to the rats. Even thought rats were eating bean, nut allergy was initiated. Few cases proved that transgenic allergy can be induced even if animal is not allergic to plants when they are given separately. And now let’s mix effects of both pesticide and genetic modification in one experiment. French researchers used transgenic corn combined with pesticide residues and experimented for 2 years on 200 rats. Animals were fed with transgenic corn from day one. Blood test (biochemistry, hormone levels…) and histological examinations were performed. Results were devastating. 97% of females developed mammary tumors, while renal tumors dominated in males. In both cases, altered hormonal levels initiated tumor formation. Pesticide affected liver, kidney, embryo… exerting typical toxic effects. Taken together, they shortened animal’s life dramatically. When those two were compared, GM food induced more severe pathologies and killed more animals showing that transgenesis itself could be more harmful then chemical poising.
This is not the first experiment showing how dangerous GM food could be, but it’s still manufactured and sold thought out the world. GM seed manufacturers are demanding a signed promise that it’s not going to be used for experimental purposes. What is that telling you? We don't know how genetically modified food affects human health. As with so many other things - time will show.
by priyasaravanan_1406 at 09-29-2012, 08:47 PM
2 comments
Cell is the tiny and the basic unit of the complex body structure. Group of cells forms tissues and group of tissues evolve into organs. The discovery and research on cell forms the basis for all the drastic development in the field of biotechnology. Like a human body composed of many organs, each cell has several components carrying out specific functions of the cell. Understanding the cell as a whole is significant to all biologists and biotechnologist. In this view, all the organelles of a cell and its functions are discussed.
The various organelles of a cell are cell membrane, nucleus, centrosome/microtubule, Golgi body, Mitochondria, Ribosome, Endoplasmic reticulum, cytoplasm, Lysosome and vacuole. These organelles have their own specific function contributing to the overall function of a cell. The role of each organelle is discussed below.
The Cell membrane: The protective covering of a cell, semi permeable in nature manages the substances entering the cell by allowing some substances into the cell and restricting others. Some of the diseases like Hyaline membrane disease, Alzheimer disease, Duchenne muscular dystrophy disrupts the cell membrane and causes dysfunction of the membrane.
The Nucleus: The nucleus of a cell holds the DNA, the genetic material. The nucleus has nucleolus where the rRNA is synthesized and also the nucleus has its own covering called the nuclear membrane. The complete understanding and research on the nucleus of a cell have unfolded the mystery behind many genetic disorders.
Cytoplasm: The area between the cell nucleus and the cell membrane where the other organelles are present.
Centrosome: Centrosome, also called as microtubule based on its structure, comprising of thick centre surrounded by projected tubules. This is situated close to the nucleus and aids in the reproduction of the cell by dividing (mitosis). The dysfunction of the components of centrosome is associated with cancer and disease like microcephaly. The absence or dysfunction of the tubules/cilia of the centrosome contributes to ciliopathies which categorizes various complex diseases.
Lysosomes: Lysosomes are called by various names like ‘stomach of the cell’, ‘recycling centre of the cell’ and ‘suicidal bags’ because of its unique function of cellular digestion and cellular substrate management. Lysosomal dysfunction causes various diseases classified under Lysosomal storage disorder.
Golgi body: Also called as the Golgi apparatus, synthesizes a membrane that surrounds the lysosome. This organelle of the cell helps in exporting the proteins and carbohydrates from the cell by packing them into membrane bound vesicles. The golgi body linked disorder is a group of congenital disorder of glycosylation.
Mitochondria: Generally called as the power house of the cell which generates energy for the cell by converting glucose into adenosine tri phosphate (ATP). Mitochondrial encephalomyopathy, Kearns-Sayre syndrome, ataxia, lactic acidosis, strokes are some of the diseases due to mitochondrial dysfunction.
Ribosome: Ribosomes, the granular particles which are either freely dispersed in the cytoplasm or attached to endoplasmic reticulum is rich in RNA and acts as the protein synthesis site. Diamond-Black fan anemia, Cartilage Hair hypoplasia, Shwachman-Diamond Syndrome, Dyskeratosis are some of the diseases associated with ribosomes.
Endoplasmic Reticulum(ER): Endoplasmic reticulum extends from the outer nuclear membrane in the cytoplasm. They are classified as rough endoplasmic reticulum and smooth endoplasmic reticulum. The rough ER have ribosomes attached to it and whereas smooth ER has no ribosomes. The rough ER is involved in the production of various proteins whereas the smooth ER manufactures lipids and other membrane proteins and also aids the transport of the produced substances to other cytoplasmic constituents like lysosome, Golgi apparatus and cell membrane.
The hyper or hypo functioning of the endoplasmic reticulum imposes a stress on the endoplasmic reticulum. This endoplasmic stress leads to various diseases like metabolic disorders including diabetes mellitus, neuro degenerative diseases and cancer.
Vacuole: Vacuole can be called as the storage unit of a cell composed of the entire digestive and digested material of a cell.
Thus the various organelles of a cell, its role in cellular function on the whole are discussed. The cell, organelles of a cell, properties of cell, types of cells and their functions, are all discussed under one roof called cell biology. Good knowledge on the subject of cell biology is significant in understanding other fields like molecular biology, biochemistry, clinical biochemistry, genetics, animal cell culture and animal cell biotechnology.
The various organelles of a cell are cell membrane, nucleus, centrosome/microtubule, Golgi body, Mitochondria, Ribosome, Endoplasmic reticulum, cytoplasm, Lysosome and vacuole. These organelles have their own specific function contributing to the overall function of a cell. The role of each organelle is discussed below.
The Cell membrane: The protective covering of a cell, semi permeable in nature manages the substances entering the cell by allowing some substances into the cell and restricting others. Some of the diseases like Hyaline membrane disease, Alzheimer disease, Duchenne muscular dystrophy disrupts the cell membrane and causes dysfunction of the membrane.
The Nucleus: The nucleus of a cell holds the DNA, the genetic material. The nucleus has nucleolus where the rRNA is synthesized and also the nucleus has its own covering called the nuclear membrane. The complete understanding and research on the nucleus of a cell have unfolded the mystery behind many genetic disorders.
Cytoplasm: The area between the cell nucleus and the cell membrane where the other organelles are present.
Centrosome: Centrosome, also called as microtubule based on its structure, comprising of thick centre surrounded by projected tubules. This is situated close to the nucleus and aids in the reproduction of the cell by dividing (mitosis). The dysfunction of the components of centrosome is associated with cancer and disease like microcephaly. The absence or dysfunction of the tubules/cilia of the centrosome contributes to ciliopathies which categorizes various complex diseases.
Lysosomes: Lysosomes are called by various names like ‘stomach of the cell’, ‘recycling centre of the cell’ and ‘suicidal bags’ because of its unique function of cellular digestion and cellular substrate management. Lysosomal dysfunction causes various diseases classified under Lysosomal storage disorder.
Golgi body: Also called as the Golgi apparatus, synthesizes a membrane that surrounds the lysosome. This organelle of the cell helps in exporting the proteins and carbohydrates from the cell by packing them into membrane bound vesicles. The golgi body linked disorder is a group of congenital disorder of glycosylation.
Mitochondria: Generally called as the power house of the cell which generates energy for the cell by converting glucose into adenosine tri phosphate (ATP). Mitochondrial encephalomyopathy, Kearns-Sayre syndrome, ataxia, lactic acidosis, strokes are some of the diseases due to mitochondrial dysfunction.
Ribosome: Ribosomes, the granular particles which are either freely dispersed in the cytoplasm or attached to endoplasmic reticulum is rich in RNA and acts as the protein synthesis site. Diamond-Black fan anemia, Cartilage Hair hypoplasia, Shwachman-Diamond Syndrome, Dyskeratosis are some of the diseases associated with ribosomes.
Endoplasmic Reticulum(ER): Endoplasmic reticulum extends from the outer nuclear membrane in the cytoplasm. They are classified as rough endoplasmic reticulum and smooth endoplasmic reticulum. The rough ER have ribosomes attached to it and whereas smooth ER has no ribosomes. The rough ER is involved in the production of various proteins whereas the smooth ER manufactures lipids and other membrane proteins and also aids the transport of the produced substances to other cytoplasmic constituents like lysosome, Golgi apparatus and cell membrane.
The hyper or hypo functioning of the endoplasmic reticulum imposes a stress on the endoplasmic reticulum. This endoplasmic stress leads to various diseases like metabolic disorders including diabetes mellitus, neuro degenerative diseases and cancer.
Vacuole: Vacuole can be called as the storage unit of a cell composed of the entire digestive and digested material of a cell.
Thus the various organelles of a cell, its role in cellular function on the whole are discussed. The cell, organelles of a cell, properties of cell, types of cells and their functions, are all discussed under one roof called cell biology. Good knowledge on the subject of cell biology is significant in understanding other fields like molecular biology, biochemistry, clinical biochemistry, genetics, animal cell culture and animal cell biotechnology.
by Ishani7 at 09-29-2012, 03:49 PM
0 comments
Gram Stain is a differential staining technique used in routine microbiological laboratory procedures which was developed by Hans Gram. It's a preliminary method in bacterial identification which divides the bacteria into gram positive and gram negative depending on the retained colour of the smear. This technique makes use of two basic stains; Crystal violet and Safranin, a mordant (Iodine), and a decolourizing agent which is alcohol. However there are bacterial species which do not give a clear difference in the colour or which doesn’t stain at all and known as gram variable or acid fast bacteria. It’s also possible to differentiate gram positive and gram negative bacteria using Potassium Hydroxide (3%) in which gram negative bacteria form a mucoid string.
Basic dyes such as Crystal Violet, Saffranin consist of coloured positive ions called as chromophores. These chromophores get attracted to the bacterial cells which are negatively charged at pH 7. In this procedure, Crystal Violet stains the smear in purple colour and in the subsequent step Iodine is applied which intensifies the purple colour of the stain. Iodine increases the affinity of the stain to the cells and coats the cell structure. Crystal Violet forms a complex with Iodine known as CV-I complex, which is larger in size than Crystal Violet molecules. In the decolourizing step, gram positive bacteria can retain the colour of the primary stain. When Safranin, the counterstain; is applied gram negative bacteria which are decolourized stains in pink. However it’s the structure of the cell wall of bacteria which results in this differential staining.
In case of gram positive bacteria, the peptidoglycan layer is thicker when compared to gram negative bacteria. Peptidoglycan is made up of two monosaccharaides; N- acetylglucosamine (NAG) and N- acetylmuramic acid (NAM) linked in an alternating fashion to form a carbohydrate backbone. Alternating disaccharide chains are linked by polypeptide chains of which the composition is different in gram positive and gram negative bacteria. Amino acids in the tetrapeptide side chains attached to NAM and NAG units occur in D and L forms which is unique about proteins.
Thicker peptidoglycan layer in gram positive bacteria helps to retain the CV-I complex in staining. In contrast, gram negative bacteria have higher lipopolysaccharide content in their cell wall which disrupts in alcohol treatment. The lipopolysaccharide layer is composed of Lipid A, Core polysaccharide and O polysaccharide. The disruption of lipopolysaccharide layer creates pores in the cell wall and the cell wall permeability increases resulting in escape of CV-I molecules. So the decolourized cells, takes the colour of Safranin. Age of the bacterial culture is a key factor in determining the gram character. Old cultures may produce unacceptable results.
Apart from the difference in the peptidoglycan layer, there are many differences in gram positive and gram negative bacteria. Gram positive cell wall contains Techoic acids which are important for antigenic specificity. This is correlated with identification procedures. Gram negative bacteria lack Techoic acids. O polysaccharide in gram negative cell wall lipopolysaccharide layer is important to distinguish bacterial species. Possessing a periplasmic space is unique to gram negative bacteria. Because of these structural differences, gram character is important in identification of bacteria in laboratory procedures.
However, this technique is not widely accepted as a standard due to existence of gram variable and acid fast bacterial species. These include; Mycobacterium which are acid fast bacteria, some Actinomycetes strains. Gram variable results may also produce because of mistakes made during the staining procedure such as excessive heating of the smear, excessive decolourizing, old cultures, uneven smears etc.
Gram negative bacteria are bacteria are generally more resistant to antibiotics due to the presence of lipopolysaccharide layer. These include clinically important bacteria such as E. coli, Salmonella, and Shigella. Gram positive bacteria are more sensitive to antibiotics like Penicillins and Cephalosporins. Gram positive bacteria include Bacillus sp., Streptococcus sp., Staphylococcus sp. which are known as human pathogens.
Gram staining along with other biochemical tests such as catalase, oxidase, fermentation of different sugars, IMVIC tests is used for further bacterial identification. Gram character is also important in prescribing medicine for human bacterial diseases. Apart from gram staining, other staining techniques used in the laboratory include acid fast staining, endospore staining, flagella staining etc.
Basic dyes such as Crystal Violet, Saffranin consist of coloured positive ions called as chromophores. These chromophores get attracted to the bacterial cells which are negatively charged at pH 7. In this procedure, Crystal Violet stains the smear in purple colour and in the subsequent step Iodine is applied which intensifies the purple colour of the stain. Iodine increases the affinity of the stain to the cells and coats the cell structure. Crystal Violet forms a complex with Iodine known as CV-I complex, which is larger in size than Crystal Violet molecules. In the decolourizing step, gram positive bacteria can retain the colour of the primary stain. When Safranin, the counterstain; is applied gram negative bacteria which are decolourized stains in pink. However it’s the structure of the cell wall of bacteria which results in this differential staining.
In case of gram positive bacteria, the peptidoglycan layer is thicker when compared to gram negative bacteria. Peptidoglycan is made up of two monosaccharaides; N- acetylglucosamine (NAG) and N- acetylmuramic acid (NAM) linked in an alternating fashion to form a carbohydrate backbone. Alternating disaccharide chains are linked by polypeptide chains of which the composition is different in gram positive and gram negative bacteria. Amino acids in the tetrapeptide side chains attached to NAM and NAG units occur in D and L forms which is unique about proteins.
Thicker peptidoglycan layer in gram positive bacteria helps to retain the CV-I complex in staining. In contrast, gram negative bacteria have higher lipopolysaccharide content in their cell wall which disrupts in alcohol treatment. The lipopolysaccharide layer is composed of Lipid A, Core polysaccharide and O polysaccharide. The disruption of lipopolysaccharide layer creates pores in the cell wall and the cell wall permeability increases resulting in escape of CV-I molecules. So the decolourized cells, takes the colour of Safranin. Age of the bacterial culture is a key factor in determining the gram character. Old cultures may produce unacceptable results.
Apart from the difference in the peptidoglycan layer, there are many differences in gram positive and gram negative bacteria. Gram positive cell wall contains Techoic acids which are important for antigenic specificity. This is correlated with identification procedures. Gram negative bacteria lack Techoic acids. O polysaccharide in gram negative cell wall lipopolysaccharide layer is important to distinguish bacterial species. Possessing a periplasmic space is unique to gram negative bacteria. Because of these structural differences, gram character is important in identification of bacteria in laboratory procedures.
However, this technique is not widely accepted as a standard due to existence of gram variable and acid fast bacterial species. These include; Mycobacterium which are acid fast bacteria, some Actinomycetes strains. Gram variable results may also produce because of mistakes made during the staining procedure such as excessive heating of the smear, excessive decolourizing, old cultures, uneven smears etc.
Gram negative bacteria are bacteria are generally more resistant to antibiotics due to the presence of lipopolysaccharide layer. These include clinically important bacteria such as E. coli, Salmonella, and Shigella. Gram positive bacteria are more sensitive to antibiotics like Penicillins and Cephalosporins. Gram positive bacteria include Bacillus sp., Streptococcus sp., Staphylococcus sp. which are known as human pathogens.
Gram staining along with other biochemical tests such as catalase, oxidase, fermentation of different sugars, IMVIC tests is used for further bacterial identification. Gram character is also important in prescribing medicine for human bacterial diseases. Apart from gram staining, other staining techniques used in the laboratory include acid fast staining, endospore staining, flagella staining etc.
by BojanaL at 09-28-2012, 07:44 PM
0 comments
Whenever we get sick we are instinctively swallowing various pills in order to help our organism win the battle with microorganisms that are disturbing our normal functioning or to soothe inner biochemical reactions that are responsible for the pain we are feeling. Traditional healing using the herbs is probably as old as mankind is, but discovery of penicillin and synthetic compounds (that could accelerate healing process or help regenerate our vital functions) started an avalanche in pharmaceutical industry.
Every drug that ends up on the shelf in the pharmacy is taking a long way to get there. Drug development and following safety assessment phases are lasting between 10 and 15 years and whole process is very expensive (roughly estimated: > billion dollars). First, potential molecule needs to be selected and chemically approved as one that has specific type of activity that will reduce or completely diminish biological process responsible for illness. Animal safety comes next. Time is important factor in this phase as adverse affects can be reflected in the offspring also. Finally, after years of testing on various animals, drug is entering clinical phases. Healthy volunteers are used in the first phase where doctors are monitoring drug’s effects on the healthy organism. Healing effects of the drug are tested on a small group of a sick people in the phase 2, followed by the tests on a bigger group of sick individuals in the phase 3 where statistically significant data will be gathered and final judgment on drug’s pluses and minuses will be given. Thousands of molecules are thrown away after just a couple of experiments at the beginning of the drug discovery process. Couple potential compounds are entering preclinical study stage where their safety, toxicity, pharmacokinetics… will be tested. In vitro experiments with cultivated cells derived from different organs or organisms are used during certain experimental phases, but most experiments are focused and held on live animals (mice, rats, dogs, chimpanzees…) called in vivo experiments. In vivo tests are causing a lot of suffering to the animals considering that numerous experiments are taking place all over the globe and the high number of the (often aggressive) chemicals are applying at the highest dose in order to check all kinds of adverse effects. Sad but true: every marketed drug is stamped with a blood of a large number of innocent animals. Most people said that we shouldn’t care or be concerned for experimental animals as they are sacrificed for human’s well-being. I couldn’t agree less! Luckily, good news for all animals and animal lovers are just around the corner. According to the latest medical laws, number of animal experiments will be restricted in the near future and replaced with computerized simulations.
Main characteristic of each drug (besides being relatively safe for consumer’s health) is that it can “locate” and “combat” altered biological process that is triggering the illness. Biochemistry of the biological processes inside of our bodies is well known to the scientists. If you can recognize the pathology – you’ll be able to find the solution (destroying cancer cells by affecting tumor vasculogenesis, for example). Chemical properties of either natural or synthetic compounds are tightly related to their structures. Whenever you have two compounds with similar structures – you can count on the similarity in their “chemical behavior”. One can be less toxic or metabolized easier than the other and those small but important differences can be crucial during drug development process. In silico (computer based) methods are very handy, helpful and cost & time reductive options that are often used both for chemical analysis as well as for toxicity prediction. Basically, those are specifically designed software that are using integrated algorithms to compare chemical structure of the compound of interest with the compound that is well known, well explored and already in the system. Higher similarity – higher possibility to express similar behavior within organism (possible side effects, effectiveness against illness…).
Industry of in silico tool is growing and developing rapidly. By using some of those tools drug development process could be accelerated for sure. Millions of dollars could be saved by shortening the preselecting phase where less potential compounds could be eliminated instantly. Not to mention keeping animals safe and sound!
Every drug that ends up on the shelf in the pharmacy is taking a long way to get there. Drug development and following safety assessment phases are lasting between 10 and 15 years and whole process is very expensive (roughly estimated: > billion dollars). First, potential molecule needs to be selected and chemically approved as one that has specific type of activity that will reduce or completely diminish biological process responsible for illness. Animal safety comes next. Time is important factor in this phase as adverse affects can be reflected in the offspring also. Finally, after years of testing on various animals, drug is entering clinical phases. Healthy volunteers are used in the first phase where doctors are monitoring drug’s effects on the healthy organism. Healing effects of the drug are tested on a small group of a sick people in the phase 2, followed by the tests on a bigger group of sick individuals in the phase 3 where statistically significant data will be gathered and final judgment on drug’s pluses and minuses will be given. Thousands of molecules are thrown away after just a couple of experiments at the beginning of the drug discovery process. Couple potential compounds are entering preclinical study stage where their safety, toxicity, pharmacokinetics… will be tested. In vitro experiments with cultivated cells derived from different organs or organisms are used during certain experimental phases, but most experiments are focused and held on live animals (mice, rats, dogs, chimpanzees…) called in vivo experiments. In vivo tests are causing a lot of suffering to the animals considering that numerous experiments are taking place all over the globe and the high number of the (often aggressive) chemicals are applying at the highest dose in order to check all kinds of adverse effects. Sad but true: every marketed drug is stamped with a blood of a large number of innocent animals. Most people said that we shouldn’t care or be concerned for experimental animals as they are sacrificed for human’s well-being. I couldn’t agree less! Luckily, good news for all animals and animal lovers are just around the corner. According to the latest medical laws, number of animal experiments will be restricted in the near future and replaced with computerized simulations.
Main characteristic of each drug (besides being relatively safe for consumer’s health) is that it can “locate” and “combat” altered biological process that is triggering the illness. Biochemistry of the biological processes inside of our bodies is well known to the scientists. If you can recognize the pathology – you’ll be able to find the solution (destroying cancer cells by affecting tumor vasculogenesis, for example). Chemical properties of either natural or synthetic compounds are tightly related to their structures. Whenever you have two compounds with similar structures – you can count on the similarity in their “chemical behavior”. One can be less toxic or metabolized easier than the other and those small but important differences can be crucial during drug development process. In silico (computer based) methods are very handy, helpful and cost & time reductive options that are often used both for chemical analysis as well as for toxicity prediction. Basically, those are specifically designed software that are using integrated algorithms to compare chemical structure of the compound of interest with the compound that is well known, well explored and already in the system. Higher similarity – higher possibility to express similar behavior within organism (possible side effects, effectiveness against illness…).
Industry of in silico tool is growing and developing rapidly. By using some of those tools drug development process could be accelerated for sure. Millions of dollars could be saved by shortening the preselecting phase where less potential compounds could be eliminated instantly. Not to mention keeping animals safe and sound!
by Kamat2010 at 09-28-2012, 05:45 PM
0 comments
Liver is a multitasking organ in the body being able to synthesise several plasma proteins, immune factors as well as several metabolising enzymes and factors helping in digestion and excretion within the body. Hence, on liver failure several severe complications are noticed in the body affecting several other organs like kidney, brain, and even causing ultimate death. Although, liver transplantation remains the ultimate solution in case of Acute Liver Failure (ALF) but due to shortage in the availability of donors, other methods to support the liver functions are being devised. Doctors have made progress in the replacement of the different damaged organs within the body with artificial devices when transplantation becomes an issue due to unavailability of the donors or organs. In case of ALF also, Artificial Liver Support Devices (ALSDs) have been developed, which provide a temporary solution between the ALF and liver transplantation or liver regeneration from the donor liver hepatocytes, which have the capacity to regenerate the whole liver and restore its function by continuous proliferation.
ALSDs are based on the idea of removal of toxic substances from the blood. These may be of two types: Non-Biological LSDs and Biological LSDs. The Non-biological LSDs mainly remove the excretory wastes from the body based on the dialysis and filtration principle. It was found that they provide temporary solution and are not much efficient as they are unable to restore other important functions of liver because of which the patients could not survive for long. This led to the idea of development of LSDs, which are biological in nature and could provide long-lasting solution for the survival of the ALF patients. The synthetic, metabolic as well as excretion functions of the liver are being restored largely by the biological LSDs, hence research on bio artificial liver devices is making progress.
The Bio artificial livers are support devices connected to the patients’ plasma circulation outside the body. They are liver cells charged bioreactors, which help in restoring almost all the main functions of the liver. The bioreactors mainly consist of porcine or human hepatocytes, which are parenchymal in nature. However, for the optimum function of the bioreactors, they must contain mixed differentiated cells whereby the liver cells possess 3D configuration. The bioreactors are of four types: hollow fiber types; suspension or encapsulation; monolayer and scaffolds. The bioreactors are mainly used for the improvement in the cell oxygenation as well as mass- exchange. In most of the cases, it is seen that the bioreactors do not consist of the biliary system, which aids in the excretion of conjugated bilirubin. Hence, for proper excretion of this bilirubin, an artificial mode is attached to the bioreactors, which help in the removal of this bilirubin, thereby preventing toxicity.
The bio artificial livers consist mainly of the freshly isolated or cryopreserved porcine hepatocytes as they are easily available. Though, they may provide reliable data regarding the restoration of function of the liver function due to similar biologic properties like human hepatocytes, but there are a number of disadvantages regarding their use. The xenozoonosis i.e xeno transplantation effect due to using cells of different species causes unreliability in the data observed by using porcine hepatocytes in the bioreactors. The transmission of the pathogens like porcine retrovirus also is another added disadvantage in their use. Hence, freshly isolated human hepatocytes must be used as cryopreservation of the same causes the loss of the enzyme function largely. The research carried out using human-origin hepatocytes provides reliable data regarding the advantages in using bioreactors in the treatment of ALF. Immortal hepatocytes developed from hepatoblastoma cell line or other tumor cells have also been developed for the study of bioreactors, though the possible toxicity resulting from using such cells cannot be ignored. Hepatocytes have also been developed from the tissues slices of the discarded donor livers, though their availability at the required time cannot be guaranteed.
The clinical proofs regarding the use of bio artificial livers are not much favourable in the present scenario. The hepatocytes used in the bioreactors may not always be completely differentiated ensuring proper function nor are they always present in 3D conformation. Moreover, the patients used for clinical trials are diverse in nature; hence, the resulting statistical data may not provide concrete positive result. The bioartificial livers may provide bridge in the treatment of the patients until the availability of the liver to be transplanted, but the lasting effect of the use of bioartificial livers on the patients after transplantation has not yet been proved completely. The clinical trials with the human hepatocytes are going on and much research is needed before the bio artificial livers can be successfully used in the treatment of the ALF patients.
ALSDs are based on the idea of removal of toxic substances from the blood. These may be of two types: Non-Biological LSDs and Biological LSDs. The Non-biological LSDs mainly remove the excretory wastes from the body based on the dialysis and filtration principle. It was found that they provide temporary solution and are not much efficient as they are unable to restore other important functions of liver because of which the patients could not survive for long. This led to the idea of development of LSDs, which are biological in nature and could provide long-lasting solution for the survival of the ALF patients. The synthetic, metabolic as well as excretion functions of the liver are being restored largely by the biological LSDs, hence research on bio artificial liver devices is making progress.
The Bio artificial livers are support devices connected to the patients’ plasma circulation outside the body. They are liver cells charged bioreactors, which help in restoring almost all the main functions of the liver. The bioreactors mainly consist of porcine or human hepatocytes, which are parenchymal in nature. However, for the optimum function of the bioreactors, they must contain mixed differentiated cells whereby the liver cells possess 3D configuration. The bioreactors are of four types: hollow fiber types; suspension or encapsulation; monolayer and scaffolds. The bioreactors are mainly used for the improvement in the cell oxygenation as well as mass- exchange. In most of the cases, it is seen that the bioreactors do not consist of the biliary system, which aids in the excretion of conjugated bilirubin. Hence, for proper excretion of this bilirubin, an artificial mode is attached to the bioreactors, which help in the removal of this bilirubin, thereby preventing toxicity.
The bio artificial livers consist mainly of the freshly isolated or cryopreserved porcine hepatocytes as they are easily available. Though, they may provide reliable data regarding the restoration of function of the liver function due to similar biologic properties like human hepatocytes, but there are a number of disadvantages regarding their use. The xenozoonosis i.e xeno transplantation effect due to using cells of different species causes unreliability in the data observed by using porcine hepatocytes in the bioreactors. The transmission of the pathogens like porcine retrovirus also is another added disadvantage in their use. Hence, freshly isolated human hepatocytes must be used as cryopreservation of the same causes the loss of the enzyme function largely. The research carried out using human-origin hepatocytes provides reliable data regarding the advantages in using bioreactors in the treatment of ALF. Immortal hepatocytes developed from hepatoblastoma cell line or other tumor cells have also been developed for the study of bioreactors, though the possible toxicity resulting from using such cells cannot be ignored. Hepatocytes have also been developed from the tissues slices of the discarded donor livers, though their availability at the required time cannot be guaranteed.
The clinical proofs regarding the use of bio artificial livers are not much favourable in the present scenario. The hepatocytes used in the bioreactors may not always be completely differentiated ensuring proper function nor are they always present in 3D conformation. Moreover, the patients used for clinical trials are diverse in nature; hence, the resulting statistical data may not provide concrete positive result. The bioartificial livers may provide bridge in the treatment of the patients until the availability of the liver to be transplanted, but the lasting effect of the use of bioartificial livers on the patients after transplantation has not yet been proved completely. The clinical trials with the human hepatocytes are going on and much research is needed before the bio artificial livers can be successfully used in the treatment of the ALF patients.
by O.P.H at 09-28-2012, 10:26 AM
4 comments
I need to come up with an idea for a biotech product or service that I can turn into a business for my college course. Finding it very hard to come up with a novel workable idea without ripping someone off. Came up with ideas like home bioreacter for turning food waste into methane, a protein water, an insulin reader thing, I dunno. Any simple ideas would be greatly appreciated
by UBIFRANCE North America at 09-28-2012, 07:17 AM
0 comments
If so, we are organizing a B2B business event and bring in California a delegation of French Innovative Biotech companies.
Called the "French Biotech Tour", the event will be held on Oct16th in San Francisco & on Oct18th in San Diego
If you are a company or an academic and you want to explore new partnerships, feel free to contact me !
To have an idea of What is a French Biotech Tour, check this video: http://www.youtube.com/watch?v=2vojPBiNI...ature=plcp
Called the "French Biotech Tour", the event will be held on Oct16th in San Francisco & on Oct18th in San Diego
If you are a company or an academic and you want to explore new partnerships, feel free to contact me !
To have an idea of What is a French Biotech Tour, check this video: http://www.youtube.com/watch?v=2vojPBiNI...ature=plcp
by BojanaL at 09-27-2012, 11:12 PM
0 comments
Modern society is growing exponentially. Wave of industrialization at the beginning of the 19th century accelerated the life style. That period is most famous for a rapid development of a numerous machines that speeded up production of consumer goods and brought us couple of new materials that were fast to produce, ease to use and applicable in so many aspects of our life. Plastic (beside the rubber developed at the same time) and all kind of items made of plastic soon became inevitable and very important part of our lifestyle.
Parkesine is the first known plastic patented by Alexander Parks in 1856th year. It consisted of cellulose treated with nitric acid. The obtained material was not particularly strong and didn't last for a long period of time, but it paved a path for further plastic development. First synthetic plastic called bakelite emerged in the early 20th century when Baekeland start experimenting with phenol and formaldehyde. He mixed them and ended up with non-conductive and heat resistant material that served perfectly as electric insulator. Even thought at the beginning plastic was made out of natural materials its future development was more focused on synthetic polymers where polystyrene, polyvinyl, nylon...were the most famous ones. Today’s plastic is made out of fossil fuels (petroleum) almost exclusively.
Bags, containers of different size and shape, bottles, phones, remote controls, handles on refrigerators, garbage cans, watering cans, light switches, chairs.... plastic is all over the place! Manufacturing process is relatively simple and inexpensive and plastic is available everywhere on the planet to be used for numerous purposes. But plastic has a dark side. Huge amount of CO2 is released during production of plastic which directly increases greenhouse effect and plastic waste contribute greatly to the overall pollution of the planet. Plastic can’t be degraded by microorganisms as it is artificial material and microorganisms don’t have enzymes necessary to digest it. Roughly estimated, lifespan of the plastic bag is between 500 and 1000 years. I have read somewhere that Chinese people spend three billion plastic bags a day! I bet that 2.9 billion end up in the nature.
Bags and other items made of plastic are considered one of the biggest natural pollutants and besides "decorating" plants in cities they can be fatal to wildlife. Birds can easily tangle their beaks or wings in a plastic bag; sea animals could swallow plastic waste because they could easily mix it with something that is normally found in their environment.... Sad story of that kind are endless.
Modern society are trying to solve the problem of excess plastic waste by sorting and recycling it, by stimulating eco-consciousness in humans and by penalties for improper disposal of garbage ...
What truly can solve the problem and save the planet is creation of biodegradable plastics.
Unlike "classic plastic", biodegradable plastics are made of natural materials: corn starch, pea starch, vegetable oil... Like conventional plastics, biodegradable plastic have very diverse applications: it’s used for packaging (various types of food and drink containers), for insulation, medical implants (that will be broken down within the body after a while), for compostable mulch films that protect crops from weeds and conserve moisture (there’s no need to collected them later since they are biodegradable and will break down on their own after a while)… Most biodegradable plastic items are disposable instead to be used multiple times.
50% of biodegradable plastics in the world are made out of starch. The addition of sorbitol and glycerin are providing typical "plastic" structure. Remaining 50% of bioplastics are generated by treating cellulose, or our of polylactic acid (cane sugar and glucose are starting points in this technology), out of poly-3-hydroxybutyrate (after treating sugar, starch, waste water with certain kind of bacteria), polyhydroxyalkanoates (using bacteria that ferment sugar and fat)....
Although today's bioplastics manufacturing techniques are expensive, demand for that particular type of plastic and its widespread use will inevitably reduce their price. We should start working on our eco awareness and we should reduce unnecessary plastic consumption to a minimum. Looking in the long term, that way we could improve the health of our planet along with its inhabitant. We should all go green as much as possible!
Parkesine is the first known plastic patented by Alexander Parks in 1856th year. It consisted of cellulose treated with nitric acid. The obtained material was not particularly strong and didn't last for a long period of time, but it paved a path for further plastic development. First synthetic plastic called bakelite emerged in the early 20th century when Baekeland start experimenting with phenol and formaldehyde. He mixed them and ended up with non-conductive and heat resistant material that served perfectly as electric insulator. Even thought at the beginning plastic was made out of natural materials its future development was more focused on synthetic polymers where polystyrene, polyvinyl, nylon...were the most famous ones. Today’s plastic is made out of fossil fuels (petroleum) almost exclusively.
Bags, containers of different size and shape, bottles, phones, remote controls, handles on refrigerators, garbage cans, watering cans, light switches, chairs.... plastic is all over the place! Manufacturing process is relatively simple and inexpensive and plastic is available everywhere on the planet to be used for numerous purposes. But plastic has a dark side. Huge amount of CO2 is released during production of plastic which directly increases greenhouse effect and plastic waste contribute greatly to the overall pollution of the planet. Plastic can’t be degraded by microorganisms as it is artificial material and microorganisms don’t have enzymes necessary to digest it. Roughly estimated, lifespan of the plastic bag is between 500 and 1000 years. I have read somewhere that Chinese people spend three billion plastic bags a day! I bet that 2.9 billion end up in the nature.
Bags and other items made of plastic are considered one of the biggest natural pollutants and besides "decorating" plants in cities they can be fatal to wildlife. Birds can easily tangle their beaks or wings in a plastic bag; sea animals could swallow plastic waste because they could easily mix it with something that is normally found in their environment.... Sad story of that kind are endless.
Modern society are trying to solve the problem of excess plastic waste by sorting and recycling it, by stimulating eco-consciousness in humans and by penalties for improper disposal of garbage ...
What truly can solve the problem and save the planet is creation of biodegradable plastics.
Unlike "classic plastic", biodegradable plastics are made of natural materials: corn starch, pea starch, vegetable oil... Like conventional plastics, biodegradable plastic have very diverse applications: it’s used for packaging (various types of food and drink containers), for insulation, medical implants (that will be broken down within the body after a while), for compostable mulch films that protect crops from weeds and conserve moisture (there’s no need to collected them later since they are biodegradable and will break down on their own after a while)… Most biodegradable plastic items are disposable instead to be used multiple times.
50% of biodegradable plastics in the world are made out of starch. The addition of sorbitol and glycerin are providing typical "plastic" structure. Remaining 50% of bioplastics are generated by treating cellulose, or our of polylactic acid (cane sugar and glucose are starting points in this technology), out of poly-3-hydroxybutyrate (after treating sugar, starch, waste water with certain kind of bacteria), polyhydroxyalkanoates (using bacteria that ferment sugar and fat)....
Although today's bioplastics manufacturing techniques are expensive, demand for that particular type of plastic and its widespread use will inevitably reduce their price. We should start working on our eco awareness and we should reduce unnecessary plastic consumption to a minimum. Looking in the long term, that way we could improve the health of our planet along with its inhabitant. We should all go green as much as possible!
by Kamat2010 at 09-27-2012, 10:12 PM
2 comments
Biotechnology has played a diverse role in the application of science in different spheres of life. Gene transfer, Recombinant DNA technology, development of vaccines including DNA-vaccines, development of hybrid plants, genetic modifications, etc are some of the areas where biotechnology has played a major role. Biotechnology also has an important role in food processing whereby it helps in targeting the microorganisms in the bio-processed foods thereby improving the quality and safety regarding the consumption of such products.
Food processing is a process by which non-palatable and easily perishable raw materials are converted to edible and potable foods and beverages, which have a longer shelf life. The method, by which the microbial organisms and their derivatives are used to increase the edibility and the shelf life of foods, is known as fermentation. Almost one-third of the diet in the whole world consists of fermented food. Hence the process of fermentation must be carefully monitored especially in rural areas as improper method of fermentation may cause contamination of food thereby, affecting the health of the people. Fermentation is also used in preparing microbial cultures, food additives, preservatives, etc.
Biotechnology has a major application in the food sector. It helps in improving the edibility, texture, and storage of the food; in preventing the attack of the food, mainly dairy, by the virus like bacteriophage; producing antimicrobial effect to destroy the unwanted microorganisms in food that cause toxicity; to prevent the formation of mycotoxins; and degradation of other toxins and anti-nutritional elements present naturally in food. The advance in application of biotechnology in food processing mainly concerns with the traditional approach of improving the strains of microorganisms and development of further improved micro-organic derivatives like enzymes, etc. Before application of various techniques, the characterization of the genetics of the microorganisms is very essential as it gives a clear idea about the favourable and non-favourable factors that affect the growth of the microorganisms. Improved strains of microorganisms can be produced by a variety of techniques like genetic modification by mutagenesis by exposure to various chemicals, gene transfer mediated conjugation by using plasmid DNA, or by genetic recombination by hybridisation with better yielding microorganism (E.g. Yeast). Recombinant DNA technology also plays an important role in modification of the genetics of the microorganisms favourably by accelerating the expression of favourable genes and hindering that of non-favourable ones by the introduction of plasmid vectors, which are food grade. In all the cases, genomic study of the microorganisms related to food is essential as it acts as a guide in identifying the metabolic process as well as the genetic mechanisms. From this, the genes responsible for the production of favourable enzymes and sugars for fermentation are identified and the application of proteomics for the identification of the proteins responsible and the interactions between proteins for the improved fermentation process is possible.
Biotechnology also plays a very important role in protein engineering. In this, favourable enzymes of the microorganisms, which are responsible for the improved fermentation, are produced commercially at a large scale by culturing the microorganisms in tanks, etc. From the industrial culture of the bacteria, the enzymes produced as metabolites can be isolated and used in food industry. This production of enzymes at such large scale makes the availability of the enzymes at reduced cost with good quality possible. Moreover, modified enzymes with improved efficiency have also been made possible by the genetic modification of the microorganisms. These modified enzymes have better thermo stability as well as novel protein structure that make them more desirable having activity on different pHs other than the usual pH of the enzyme as well as act on different substrates.
Various amino acids, food-flavouring agents, food additives, and preservatives are all different derivatives obtained from different microorganisms. Biotechnology helps in understanding the metabolic pathways of the microorganisms thereby helping in isolating the required derivatives. The technology also helps in the identification of the pathogens, pesticides, as well as anti-nutritional factors present in the food. It helps identifying various contaminants like mycotoxins, which cause decrease in shelf life of the foods as well as cause toxicity of foods, by different tests like ELISA, microarray, etc. Although, Biotechnology plays a very important role in the food processing industry, much advance has not been made in this area mainly in developing countries due to socio-economic factors of the population. Research in this area is possible only if the government of the developing countries gives support and makes improvement in the development policies regarding the food sector.
Food processing is a process by which non-palatable and easily perishable raw materials are converted to edible and potable foods and beverages, which have a longer shelf life. The method, by which the microbial organisms and their derivatives are used to increase the edibility and the shelf life of foods, is known as fermentation. Almost one-third of the diet in the whole world consists of fermented food. Hence the process of fermentation must be carefully monitored especially in rural areas as improper method of fermentation may cause contamination of food thereby, affecting the health of the people. Fermentation is also used in preparing microbial cultures, food additives, preservatives, etc.
Biotechnology has a major application in the food sector. It helps in improving the edibility, texture, and storage of the food; in preventing the attack of the food, mainly dairy, by the virus like bacteriophage; producing antimicrobial effect to destroy the unwanted microorganisms in food that cause toxicity; to prevent the formation of mycotoxins; and degradation of other toxins and anti-nutritional elements present naturally in food. The advance in application of biotechnology in food processing mainly concerns with the traditional approach of improving the strains of microorganisms and development of further improved micro-organic derivatives like enzymes, etc. Before application of various techniques, the characterization of the genetics of the microorganisms is very essential as it gives a clear idea about the favourable and non-favourable factors that affect the growth of the microorganisms. Improved strains of microorganisms can be produced by a variety of techniques like genetic modification by mutagenesis by exposure to various chemicals, gene transfer mediated conjugation by using plasmid DNA, or by genetic recombination by hybridisation with better yielding microorganism (E.g. Yeast). Recombinant DNA technology also plays an important role in modification of the genetics of the microorganisms favourably by accelerating the expression of favourable genes and hindering that of non-favourable ones by the introduction of plasmid vectors, which are food grade. In all the cases, genomic study of the microorganisms related to food is essential as it acts as a guide in identifying the metabolic process as well as the genetic mechanisms. From this, the genes responsible for the production of favourable enzymes and sugars for fermentation are identified and the application of proteomics for the identification of the proteins responsible and the interactions between proteins for the improved fermentation process is possible.
Biotechnology also plays a very important role in protein engineering. In this, favourable enzymes of the microorganisms, which are responsible for the improved fermentation, are produced commercially at a large scale by culturing the microorganisms in tanks, etc. From the industrial culture of the bacteria, the enzymes produced as metabolites can be isolated and used in food industry. This production of enzymes at such large scale makes the availability of the enzymes at reduced cost with good quality possible. Moreover, modified enzymes with improved efficiency have also been made possible by the genetic modification of the microorganisms. These modified enzymes have better thermo stability as well as novel protein structure that make them more desirable having activity on different pHs other than the usual pH of the enzyme as well as act on different substrates.
Various amino acids, food-flavouring agents, food additives, and preservatives are all different derivatives obtained from different microorganisms. Biotechnology helps in understanding the metabolic pathways of the microorganisms thereby helping in isolating the required derivatives. The technology also helps in the identification of the pathogens, pesticides, as well as anti-nutritional factors present in the food. It helps identifying various contaminants like mycotoxins, which cause decrease in shelf life of the foods as well as cause toxicity of foods, by different tests like ELISA, microarray, etc. Although, Biotechnology plays a very important role in the food processing industry, much advance has not been made in this area mainly in developing countries due to socio-economic factors of the population. Research in this area is possible only if the government of the developing countries gives support and makes improvement in the development policies regarding the food sector.
by Kamat2010 at 09-27-2012, 09:13 PM
1 comments
Nanotechnology has opened up a new area of research for the disease diagnosis as well as therapeutics. Though drug discovery is very essential for the proper treatment of the diseases, drug delivery remains a major concern. The agents used for drug delivery have been found to possess their own properties of cell toxicity, low persistence in the microenvironment of the body as well as impermeability across the cell membranes, which result in inefficient drug delivery within the body. Nanoparticles have emerged, as a better alternative for drug delivery in recent times though further in-depth research is essential to provide concrete evidence for the same.
Nanoparticles are usually made of elements, which are biologically less reactive and hence used for different diagnostic assays as well as therapies. The nanoparticles due to their extreme small size, zeta potential and other favourable factors have added advantage in being used as drug delivery agents. Adsorption of the proteins like antibodies or other bioactive moieties on the surface of the nanoparticles is a method by which the bioactive agents are transported to the target site in-vivo, but this method has some disadvantages because of which surface functionalization has gained importance. The adsorption on the surface technique causes the denaturation of the protein adsorbed in most of the cases and the presence of steric hindrance is one more drawback. Moreover, the nanoparticles must have to be present in the systemic circulation for a longer period. All these factors have initialized the study of surface functionalization of nanoparticles, which has become a greatly researched topic.
Surface functionalization means the introduction of chemical functional groups on the surface of the nanoparticles. The chemical groups are not directly attached to the nanoparticles but are attached using spacer arms or other lipophilic agents. Many studies have been conducted whereby PEG (Polyethylene glycol) has been used for the surface functionalization of the nanoparticles. The surface functionalized nanoparticles become capable of crossing the lipid bio layer of the membranes of the cell and thereby help in the delivery of the drugs and other bioactive agents to the target site in-vivo. The PEG spacer allows the GNPs (Gold nanoparticles) to persist in the systemic circulation within the body protected from the macrophage attack while providing flexibility also to the molecule for proper interaction with the target. Research with other surfactants apart from PEG, which can provide the same advantages as PEG in the drug delivery through nanoparticles is going on.
Surface functionalization is possible for carbon nanotubes (CNTs) also apart from GNPs. The CNTs have two ends and two surfaces (inner and outer). Hence, it provides wide possibility for functionalization on its surface thereby providing a possibility of delivery of bioactive agents within the body. The functionalization of the CNTs occurs usually by the physical adsorption of the surfactants by weakening of the van der Waals interaction within the bundle of CNTs, which may lead to the exfoliation of the CNTs. The exact mechanism of the adsorption and the nature of interaction between the CNTs and the surfactant remain unknown, though, it is suggested that in some cases the polymer coils itself around the CNTs in a helical fashion.
The surface functionalization of the nanoparticles has made tremendous progress in drug delivery through BBB. The potential drugs used for the therapy of the CNS related diseases face an enormous challenge of crossing the BBB due to which much progress in the successful treatment of the CNS related diseases has not been made. This problem has been resolved largely with the use of functionalized nanoparticles. Many possible mechanisms have been reported for the delivery of the drugs through the BBB with the use of nanoparticles. Endocytosis or transcytosis of the endothelial cell layer, dissolution of the membrane lipids of BBB due to surfactant effect, loosening of tight junctions of BBB due to the nanoparticle effect or the modification of the efflux protein in BBB thereby preventing efflux , may be some of the mechanisms by which the drug-coated nanoparticles move across BBB. Many other mechanisms have been suggested, which need proper concrete evidence as proof for the same. In this way, it is seen that surface functionalization of the nanoparticles has broadened the research related to drug delivery.
Nanoparticles are usually made of elements, which are biologically less reactive and hence used for different diagnostic assays as well as therapies. The nanoparticles due to their extreme small size, zeta potential and other favourable factors have added advantage in being used as drug delivery agents. Adsorption of the proteins like antibodies or other bioactive moieties on the surface of the nanoparticles is a method by which the bioactive agents are transported to the target site in-vivo, but this method has some disadvantages because of which surface functionalization has gained importance. The adsorption on the surface technique causes the denaturation of the protein adsorbed in most of the cases and the presence of steric hindrance is one more drawback. Moreover, the nanoparticles must have to be present in the systemic circulation for a longer period. All these factors have initialized the study of surface functionalization of nanoparticles, which has become a greatly researched topic.
Surface functionalization means the introduction of chemical functional groups on the surface of the nanoparticles. The chemical groups are not directly attached to the nanoparticles but are attached using spacer arms or other lipophilic agents. Many studies have been conducted whereby PEG (Polyethylene glycol) has been used for the surface functionalization of the nanoparticles. The surface functionalized nanoparticles become capable of crossing the lipid bio layer of the membranes of the cell and thereby help in the delivery of the drugs and other bioactive agents to the target site in-vivo. The PEG spacer allows the GNPs (Gold nanoparticles) to persist in the systemic circulation within the body protected from the macrophage attack while providing flexibility also to the molecule for proper interaction with the target. Research with other surfactants apart from PEG, which can provide the same advantages as PEG in the drug delivery through nanoparticles is going on.
Surface functionalization is possible for carbon nanotubes (CNTs) also apart from GNPs. The CNTs have two ends and two surfaces (inner and outer). Hence, it provides wide possibility for functionalization on its surface thereby providing a possibility of delivery of bioactive agents within the body. The functionalization of the CNTs occurs usually by the physical adsorption of the surfactants by weakening of the van der Waals interaction within the bundle of CNTs, which may lead to the exfoliation of the CNTs. The exact mechanism of the adsorption and the nature of interaction between the CNTs and the surfactant remain unknown, though, it is suggested that in some cases the polymer coils itself around the CNTs in a helical fashion.
The surface functionalization of the nanoparticles has made tremendous progress in drug delivery through BBB. The potential drugs used for the therapy of the CNS related diseases face an enormous challenge of crossing the BBB due to which much progress in the successful treatment of the CNS related diseases has not been made. This problem has been resolved largely with the use of functionalized nanoparticles. Many possible mechanisms have been reported for the delivery of the drugs through the BBB with the use of nanoparticles. Endocytosis or transcytosis of the endothelial cell layer, dissolution of the membrane lipids of BBB due to surfactant effect, loosening of tight junctions of BBB due to the nanoparticle effect or the modification of the efflux protein in BBB thereby preventing efflux , may be some of the mechanisms by which the drug-coated nanoparticles move across BBB. Many other mechanisms have been suggested, which need proper concrete evidence as proof for the same. In this way, it is seen that surface functionalization of the nanoparticles has broadened the research related to drug delivery.
by Kamat2010 at 09-27-2012, 07:57 PM
2 comments
In drug discovery process, drug metabolism plays a major role and determines the fate of the prospective drugs. Drug metabolism must take place only after the drugs reach their specific target site and produce the desired effects. In addition, the nature of the metabolites produced from the drug, must be thoroughly studied; otherwise, the drugs would be rejected during the screening process. Hence, drug metabolism is a major criterion in the high-throughput screening of prospective drugs.
Drug metabolism mainly takes place in the liver, where along with metabolism of the drugs, the excretion and thus the clearance of the drugs takes place. Drug metabolism mainly takes place in two phases – Phase I and Phase II. The Phase I reactions mainly result in functionalization of the drugs whereas the Phase II reactions result in the increased polarity of the drugs due to the conjugation of a polar group on the drug, thereby increasing their solubility which helps in their excretion from the body. The Phase I reactions mainly involve the action of Cytochrome P450 enzymes, Flavin Monoxygenases, etc, while the Phase II reactions mainly involve the action of UDP glucuronyl transferases (UGTs, sulfotransferases, etc.).
The Cytochrome P450s play a very important role in drug metabolism as they help in the addition or unmasking of functional groups so that the Phase II enzymes act upon them. Cytochrome P450s are heme- containing isoenzymes present in the lipid bilayer of the endoplasmic reticulum of the hepatocytes. Since, they have a colored pigment, which absorbs light of wavelength 450nm, hence the name. Many isoenzymes of cytochrome P450s are expressed within the human body, which act upon different substrates, and of them, some play important roles in drug metabolism. The main metabolic reaction that takes place is the mixed oxidation function whereby the drug undergoes oxidation reaction with the formation of NADP in the reaction. The metabolic studies of the prospective drugs is carried out using in-vitro models like: a) microsomes (human, rat, mouse, etc) derived from the SER (Smooth Endoplasmic reticulum) of the cells; b) S9 fraction obtained from the differential centrifugation of the liver homogenate; c) fresh and cryo preserved hepatocytes; d) tissue slices; e) recombinant expressed enzymes. During the metabolic studies, cytochrome P450s have been extensively studied as Phase I reactions are greatly affected during co-administration of more than one drug. This phenomenon is known as drug – drug interaction. In the co-administration of more than one drug, either inhibition or induction of the cytochrome P450s takes place due to which the metabolism of the drugs is affected. When the metabolism of the drugs is affected, it hinders the proper action of the drugs as the drugs are either easily eliminated from the body due to faster metabolism or they remain in the cells for longer period due to inhibited metabolism producing toxic effects. Hence, drug-drug interaction study has become a part of the metabolic stability study of a prospective drug.
Drug metabolism has an important role in the determination of the pharmacokinetic (PK) parameters like oral bioavailability, clearance and the half-life of the entity within the cell. The drug metabolic studies help to screen the compounds based on their metabolic rate and thereby help to proceed with the in-vivo studies using rat, mouse, etc. The determination of the metabolite structure with the help of LC/MS-MS and the metabolic phenotyping i.e. the particular enzyme responsible for the metabolism of the prospective drug, which can be done using recombinant enzymes, gives a much clearer idea about the metabolism of the compounds and the information derived can be used for further drug-drug interaction studies. However, the metabolic phenotyping of a prospective drug is quite difficult, long-drawn and expensive process. High-throughput screening of the prospective drugs based on their metabolic stability is carried out mainly using liver microsomes in a drug research lab.
Drug metabolism is very essential in the toxicity studies too. The persistence of the compounds in the systemic circulation for long period causes toxicity and the nature of the metabolites and the reaction of the metabolites within the body, must be studied thoroughly before the compounds progress to the next stage of screening in drug discovery process. In this way, it is seen that drug metabolic studies form an integral part in drug discovery.
Drug metabolism mainly takes place in the liver, where along with metabolism of the drugs, the excretion and thus the clearance of the drugs takes place. Drug metabolism mainly takes place in two phases – Phase I and Phase II. The Phase I reactions mainly result in functionalization of the drugs whereas the Phase II reactions result in the increased polarity of the drugs due to the conjugation of a polar group on the drug, thereby increasing their solubility which helps in their excretion from the body. The Phase I reactions mainly involve the action of Cytochrome P450 enzymes, Flavin Monoxygenases, etc, while the Phase II reactions mainly involve the action of UDP glucuronyl transferases (UGTs, sulfotransferases, etc.).
The Cytochrome P450s play a very important role in drug metabolism as they help in the addition or unmasking of functional groups so that the Phase II enzymes act upon them. Cytochrome P450s are heme- containing isoenzymes present in the lipid bilayer of the endoplasmic reticulum of the hepatocytes. Since, they have a colored pigment, which absorbs light of wavelength 450nm, hence the name. Many isoenzymes of cytochrome P450s are expressed within the human body, which act upon different substrates, and of them, some play important roles in drug metabolism. The main metabolic reaction that takes place is the mixed oxidation function whereby the drug undergoes oxidation reaction with the formation of NADP in the reaction. The metabolic studies of the prospective drugs is carried out using in-vitro models like: a) microsomes (human, rat, mouse, etc) derived from the SER (Smooth Endoplasmic reticulum) of the cells; b) S9 fraction obtained from the differential centrifugation of the liver homogenate; c) fresh and cryo preserved hepatocytes; d) tissue slices; e) recombinant expressed enzymes. During the metabolic studies, cytochrome P450s have been extensively studied as Phase I reactions are greatly affected during co-administration of more than one drug. This phenomenon is known as drug – drug interaction. In the co-administration of more than one drug, either inhibition or induction of the cytochrome P450s takes place due to which the metabolism of the drugs is affected. When the metabolism of the drugs is affected, it hinders the proper action of the drugs as the drugs are either easily eliminated from the body due to faster metabolism or they remain in the cells for longer period due to inhibited metabolism producing toxic effects. Hence, drug-drug interaction study has become a part of the metabolic stability study of a prospective drug.
Drug metabolism has an important role in the determination of the pharmacokinetic (PK) parameters like oral bioavailability, clearance and the half-life of the entity within the cell. The drug metabolic studies help to screen the compounds based on their metabolic rate and thereby help to proceed with the in-vivo studies using rat, mouse, etc. The determination of the metabolite structure with the help of LC/MS-MS and the metabolic phenotyping i.e. the particular enzyme responsible for the metabolism of the prospective drug, which can be done using recombinant enzymes, gives a much clearer idea about the metabolism of the compounds and the information derived can be used for further drug-drug interaction studies. However, the metabolic phenotyping of a prospective drug is quite difficult, long-drawn and expensive process. High-throughput screening of the prospective drugs based on their metabolic stability is carried out mainly using liver microsomes in a drug research lab.
Drug metabolism is very essential in the toxicity studies too. The persistence of the compounds in the systemic circulation for long period causes toxicity and the nature of the metabolites and the reaction of the metabolites within the body, must be studied thoroughly before the compounds progress to the next stage of screening in drug discovery process. In this way, it is seen that drug metabolic studies form an integral part in drug discovery.
by Kamat2010 at 09-27-2012, 07:49 PM
3 comments
Nanotechnology has become a vastly explored area of research in the present times mainly in the biomedical research. Nanoparticles have found importance in the drug delivery, disease diagnosis, as well as therapeutic applications. Nanotechnology deals with the particles having length in the nanometer scales i.e one billionth of a meter. At such small sizes, the particles have high ratio of size to volume, which influences their reactivity and their properties as a whole changes from that of their native element.
In the biological system, drug delivery to the target system or organ has become a major issue. For instance, drug delivery through the BBB is a tough challenge. Though many drugs have proved effective potent drugs for the CNS, but due to improper drug delivery system through the BBB to the brain, successful treatment of brain-related diseases has not made much progress. It is here that nanotechnology has made a mark because of its size, surface functionalization, and other factors.
Many varieties of nanoparticles are available which have created impact in different ways such as nanotubes, liposomes, polymer of nanoparticles, dendrimer, quantum dots, micelles, etc. Nanotubes are carbon rods with diameter half as that of a DNA molecule. They are studied extensively for successful gene delivery, as well as delivering plasmid DNA, proteins, synthetic enzymes, etc. into the living system. A number of vectors like fungi, bacteria are available for gene delivery into the cells but many factors like toxicity, biodegradability, evoking immune response, etc while using those vectors have opened research in this field. Hence, nanotubes have gained much importance in this area. The nanotubes are hollow tubes with either both sides open or one side closed with a cap made of nanoparticles known as nanocap. The bioactive agent is attached to the nanotubes and then it is delivered to the target cell in the animal body or the target site in the plant by different routes such as intra-dermal, intravenous, trans-mucosal sites, etc., within the body (human or animal) or by application on the plants mechanically. The nanotubes are made with biodegradable material, which degrades after reaching the target site with time thereby releasing the bioactive agent within the body. The biodegradable material with which the nanotubes are made, are carefully selected such that it helps in the proper delivery of the bioactive agent to the target site and the nanotubes are degraded only after reaching the site of action thus releasing the bioactive agent. The nanotubes have also found application in the detection of mutations within the DNA whereby the mutated regions of the DNA are tagged using bulky molecule with tags specific for the mutated sequence. The needle-like tip of the nanotubes is then used to trace the mutated DNA, which has been tagged, and to identify alteration in the shape of the specific DNA. Thus, nanotubes play a very important part in detecting different diseases like cancer and this uniqueness of the nanotubes have made them have different applications in various fields of research like biomedicine, agriculture, industry, environmental science, etc.
Gold nanoparticles (GNPs) or Colloidal Gold has been widely used as drug delivery agents and in targeting of cancer cells due to their minimal reactivity within the biological system. Colloidal gold refers to the suspension of the nanoparticles in fluid, mainly water. Colloidal gold has been proved effective in the treatment of Rheumatoid arthritis and in the destruction of the beta amyloid plaques in the Alzheimer’s disease. Detection of the tumors in-vivo has been possible due to the GNPs with the help of SERS, Surface Enhanced Raman Spectroscopy. Other radiative applications of the colloidal gold are yet to be explored. The GNPs have also been used in many sensitive assays for diagnosis, radiotherapy, etc.
Two other nanotechnological products: Quantum dots and Nanoshells are used in diagnosis and therapy of cancer respectively. The quantum dots glow under UV light stimulation. Hence, specifically designed quantum dots can be used that bind to mutated DNA and the site of this mutated DNA can be identified in-vivo when the bound quantum dots glow under the stimulation of UV light, thus exposing the regions of localisation of mutated DNA specific for causing cancer. The nanoshells have the property of absorbing near-infrared light resulting in heat resulting in cell death. The nanoshells can be made to reach the tumor region by linking them with antibodies specific to the tumor cells and destroy the cancer cells, without affecting the neighbouring cells. Thus, nanotechnology has made great advancement in medical science.
In the biological system, drug delivery to the target system or organ has become a major issue. For instance, drug delivery through the BBB is a tough challenge. Though many drugs have proved effective potent drugs for the CNS, but due to improper drug delivery system through the BBB to the brain, successful treatment of brain-related diseases has not made much progress. It is here that nanotechnology has made a mark because of its size, surface functionalization, and other factors.
Many varieties of nanoparticles are available which have created impact in different ways such as nanotubes, liposomes, polymer of nanoparticles, dendrimer, quantum dots, micelles, etc. Nanotubes are carbon rods with diameter half as that of a DNA molecule. They are studied extensively for successful gene delivery, as well as delivering plasmid DNA, proteins, synthetic enzymes, etc. into the living system. A number of vectors like fungi, bacteria are available for gene delivery into the cells but many factors like toxicity, biodegradability, evoking immune response, etc while using those vectors have opened research in this field. Hence, nanotubes have gained much importance in this area. The nanotubes are hollow tubes with either both sides open or one side closed with a cap made of nanoparticles known as nanocap. The bioactive agent is attached to the nanotubes and then it is delivered to the target cell in the animal body or the target site in the plant by different routes such as intra-dermal, intravenous, trans-mucosal sites, etc., within the body (human or animal) or by application on the plants mechanically. The nanotubes are made with biodegradable material, which degrades after reaching the target site with time thereby releasing the bioactive agent within the body. The biodegradable material with which the nanotubes are made, are carefully selected such that it helps in the proper delivery of the bioactive agent to the target site and the nanotubes are degraded only after reaching the site of action thus releasing the bioactive agent. The nanotubes have also found application in the detection of mutations within the DNA whereby the mutated regions of the DNA are tagged using bulky molecule with tags specific for the mutated sequence. The needle-like tip of the nanotubes is then used to trace the mutated DNA, which has been tagged, and to identify alteration in the shape of the specific DNA. Thus, nanotubes play a very important part in detecting different diseases like cancer and this uniqueness of the nanotubes have made them have different applications in various fields of research like biomedicine, agriculture, industry, environmental science, etc.
Gold nanoparticles (GNPs) or Colloidal Gold has been widely used as drug delivery agents and in targeting of cancer cells due to their minimal reactivity within the biological system. Colloidal gold refers to the suspension of the nanoparticles in fluid, mainly water. Colloidal gold has been proved effective in the treatment of Rheumatoid arthritis and in the destruction of the beta amyloid plaques in the Alzheimer’s disease. Detection of the tumors in-vivo has been possible due to the GNPs with the help of SERS, Surface Enhanced Raman Spectroscopy. Other radiative applications of the colloidal gold are yet to be explored. The GNPs have also been used in many sensitive assays for diagnosis, radiotherapy, etc.
Two other nanotechnological products: Quantum dots and Nanoshells are used in diagnosis and therapy of cancer respectively. The quantum dots glow under UV light stimulation. Hence, specifically designed quantum dots can be used that bind to mutated DNA and the site of this mutated DNA can be identified in-vivo when the bound quantum dots glow under the stimulation of UV light, thus exposing the regions of localisation of mutated DNA specific for causing cancer. The nanoshells have the property of absorbing near-infrared light resulting in heat resulting in cell death. The nanoshells can be made to reach the tumor region by linking them with antibodies specific to the tumor cells and destroy the cancer cells, without affecting the neighbouring cells. Thus, nanotechnology has made great advancement in medical science.
by priyasaravanan_1406 at 09-26-2012, 11:57 PM
6 comments
Lysosomal storage disorder (LSD), the very rare inherited disorder is a condition due to lysosomal dysfunction of the cell. Lysosome, the organelle of a body cell, acts as the recycling centre of the cell by breaking down the waste substances (substrates) generated in the cell into useful product which in turn is utilized by the cell. Also, any foreign body entering the cell is evaded by lysosome. Lysosome also digests dead cells and thus its role in short can be explained as cellular substrate management and cellular digestion.
The history of Lysosomal storage disorder dates back to 1880’s even before the discovery of lysosome in 1960s. About 40 different hydrolytic enzymes (proteins) are essential for proper functioning of the lysosome. Each of these enzymes is responsible for reduction of particular substrate and deficit or absence of any of these enzymes result in substrate accumulation in the cell causing various diseases categorized under LSD. To name a few, they are Tay-Sachs disease, Gaucher disease, pompe disease, Niemann-pick disease, Farber disease, Krabbe disease, Sandhoff disease, Schindller disease, salla disease and Wolman disease. The most affected age group is children, once inherited the disease, they die even before 15 years of age. Various researches on LSD have proved the average ratio of prevalence of this disorder is 1 in 5000 live births.
The various signs and symptoms of LSD depend on the type of enzyme deficient and the particular type of cell (liver cell, brain cell and so on) which is affected due to Lysosomal dysfunction. Some of the symptoms are reduced motor skills, growth retardation, enlarged organs and rare facial features. Based on the symptoms, the adversity of the disorder is diagnosed by various techniques like enzyme assay and mutation analysis.
In enzyme assay technique, the enzyme levels in patients with LSD are assessed and compared to the desirable level. This technique is even applicable to testing fetus suspected to have inherited LSD, where the sample is collected through amniocentesis. Whereas mutation analysis is carried out for patients suspected to have inherited the disease from carriers in their family.
Treating LSD patient is a challenging task due to restriction in treatment methods and also the symptoms of LSD have adverse effects on overall body system. Most of the LSD patients are treated by managing symptoms. The few treatment methods available for specific Lysosomal storage disorder are Bone marrow transplantation, enzyme replacement therapy, substrate reduction therapy, Umbilical cord blood transplant, Gene therapy and chaperone therapy.
Bone marrow transplant involves transplanting stem cells from a healthy donor to the patient to stimulate the production of the deficient enzyme. In enzyme replacement therapy, the genetically engineered copy of the deficient enzyme is given to the patient intravenously. The rate of production of substrate responsible for the disorder is slowed by administering drugs in substrate reduction therapy. Though these methods prove to be considered treatment methods for LSD each of it has its own limitations which led to the development of research in the field of various treatment methods.
As a result the developed methods are enzyme enhancement therapy, substrate synthesis inhibition therapy, gene therapy and chaperone therapy. In enzyme enhancement therapy, the defective enzymes in LSD are stabilized and in substrate synthesis inhibition therapy applies the principle of blocking a step in substrate production thus reducing the accumulation. Gene therapy, as the name indicates the normal copy of gene replaces the mutated gene responsible for deficit enzyme, thus inducing the normal production and function of the enzyme.
Inspite of the availability of various treatment methods and diverse research to derive suitable treatment methods, the success of it depends on the condition of the patient. While treating a patient for LSD, all the other ailments, past history etc has to be taken into consideration. A complete clinical history of the patient has to be maintained and it also involves care from multidisciplinaries to treat a patient for Lysosomal storage disorder because of its complexity.
Thus the cause, symptom, diagnosis and available treatment methods for LSD is discussed. All the available treatment methods are costly and hence the earlier the diagnosis of the disease increases the maximum chances of survival from the available treatment methods. The knowledge on LSD is significant for individual and medical specialist to diagnose the disease early and treat it.
The history of Lysosomal storage disorder dates back to 1880’s even before the discovery of lysosome in 1960s. About 40 different hydrolytic enzymes (proteins) are essential for proper functioning of the lysosome. Each of these enzymes is responsible for reduction of particular substrate and deficit or absence of any of these enzymes result in substrate accumulation in the cell causing various diseases categorized under LSD. To name a few, they are Tay-Sachs disease, Gaucher disease, pompe disease, Niemann-pick disease, Farber disease, Krabbe disease, Sandhoff disease, Schindller disease, salla disease and Wolman disease. The most affected age group is children, once inherited the disease, they die even before 15 years of age. Various researches on LSD have proved the average ratio of prevalence of this disorder is 1 in 5000 live births.
The various signs and symptoms of LSD depend on the type of enzyme deficient and the particular type of cell (liver cell, brain cell and so on) which is affected due to Lysosomal dysfunction. Some of the symptoms are reduced motor skills, growth retardation, enlarged organs and rare facial features. Based on the symptoms, the adversity of the disorder is diagnosed by various techniques like enzyme assay and mutation analysis.
In enzyme assay technique, the enzyme levels in patients with LSD are assessed and compared to the desirable level. This technique is even applicable to testing fetus suspected to have inherited LSD, where the sample is collected through amniocentesis. Whereas mutation analysis is carried out for patients suspected to have inherited the disease from carriers in their family.
Treating LSD patient is a challenging task due to restriction in treatment methods and also the symptoms of LSD have adverse effects on overall body system. Most of the LSD patients are treated by managing symptoms. The few treatment methods available for specific Lysosomal storage disorder are Bone marrow transplantation, enzyme replacement therapy, substrate reduction therapy, Umbilical cord blood transplant, Gene therapy and chaperone therapy.
Bone marrow transplant involves transplanting stem cells from a healthy donor to the patient to stimulate the production of the deficient enzyme. In enzyme replacement therapy, the genetically engineered copy of the deficient enzyme is given to the patient intravenously. The rate of production of substrate responsible for the disorder is slowed by administering drugs in substrate reduction therapy. Though these methods prove to be considered treatment methods for LSD each of it has its own limitations which led to the development of research in the field of various treatment methods.
As a result the developed methods are enzyme enhancement therapy, substrate synthesis inhibition therapy, gene therapy and chaperone therapy. In enzyme enhancement therapy, the defective enzymes in LSD are stabilized and in substrate synthesis inhibition therapy applies the principle of blocking a step in substrate production thus reducing the accumulation. Gene therapy, as the name indicates the normal copy of gene replaces the mutated gene responsible for deficit enzyme, thus inducing the normal production and function of the enzyme.
Inspite of the availability of various treatment methods and diverse research to derive suitable treatment methods, the success of it depends on the condition of the patient. While treating a patient for LSD, all the other ailments, past history etc has to be taken into consideration. A complete clinical history of the patient has to be maintained and it also involves care from multidisciplinaries to treat a patient for Lysosomal storage disorder because of its complexity.
Thus the cause, symptom, diagnosis and available treatment methods for LSD is discussed. All the available treatment methods are costly and hence the earlier the diagnosis of the disease increases the maximum chances of survival from the available treatment methods. The knowledge on LSD is significant for individual and medical specialist to diagnose the disease early and treat it.
by BojanaL at 09-26-2012, 08:11 PM
4 comments
Modern human (Homo sapiens) are present on the Earth for around 200,000 years. We weren't the only hominids on the planet, but we were certainly the cleverest ones. One organ played a vital role in our successful adaptation to a hostile environment – it was a human brain. Thanks to the brain, we were able to create all kind of tools that could simplify our everyday life and facilitate battle for food and warm shelter. It all began with various weapons, followed with the discovery of fire, wheel, electricity….and now, even though we are living in a relatively safe and controlled environment, modern technology is progressing to the aspects of life we couldn't imagine 100 years ago and it’s not just omnipresent but it’s necessary.
Being curious by nature, throughout the centuries we discovered how different organisms are built, how they are working, what triggers the illness and how we can hill ourselves and/or other creatures, what are the basics of reproduction…. Today, we are combining all that knowledge with modern technology to change who we are.
Genetic engineering is one of the most investigated scientific fields with endless possibilities. Fact that all living creatures are built and are functioning thanks to the information written in their DNA (or RNA when it comes to some viruses) is what makes genetic engineering that popular. Deoxyribonucleic acid (DNA) is a main constituent of the chromosomes; it contains genetic information and ability to replicate when cell is dividing. Genes are sequences of DNA, hereditary units specifically located on chromosomes, present in two copies (one copy from each of our parents) that will determine our individual characteristic after expressing. Genome is a set of all known genes within the species. What makes us so different from each other is actually a minimal redistribution of DNA nucleotides that makes us unique and unrepeatable. 99,9% of human genome is universal to all people and just 0,10% differences in our DNA will lead to distinctive characteristics each person have. We are not that different from other species as well - most biochemical processes inside living organisms are universal or at least similar. That simple fact triggered first genetic experiments, and once they started – there was no way back.
Genes are in charge for much more than just the color of our eyes. Few enzymes and couple of RNA molecules are most important participants in the complicated and jet fascinating machinery that is controlling genetic expression. Final product of genetic expression is protein. Proteins are essential for all the biochemical processes inside the organism. Most of those processes can be described as cascade where one molecule affects other and it’s a chain reaction leading at the end to a normal breading, hormone production, neurotransmitters release – in one word – having one normal and functional organism. If gene undergoes unwanted mutation and become dysfunctional – complete process will be affected and disease will develop. That’s where genetic engineering is more than useful. For example, insulin is polypeptide essential for sugar and fat metabolism. Without insulin blood sugar level can’t be regulated and result is diabetes. People with diabetes need insulin in regular daily doses but since insulin is natural protein – its production isn’t that simple. Solution comes with recombinant DNA technique. Bacterial cells contain single DNA and one or more plasmids (a circular and chromosomally independent DNA chain inside the cell) that could incorporate foreign genes and start producing the protein we want during the genetic expression phase that is happening normally in the bacterial cell. Since the genes from different species share same chemical structure, we can easily slice plasmid’s DNA at certain spot and incorporate gene that we need to multiply using specific enzymes and create expanded DNA chain that will produce one more protein in the next genetic expression round. This technique is used for multiplying a lot of proteins where most popular examples are production of the growth hormone, clothing factor VIII, recombinant hepatitis B vaccine….
Beside bacteria, plants can also be enriched with couple of foreign genes that could either enhance their endurance and tolerance toward pests and environmental conditions or increase vitamin/protein amount…
Not all genetic engineering experiments turned to be successful and useful for human kind. As with all other experiments, finding the right balance is always the key to success, but as I mention before with genetic engineering – possibilities are endless.
Being curious by nature, throughout the centuries we discovered how different organisms are built, how they are working, what triggers the illness and how we can hill ourselves and/or other creatures, what are the basics of reproduction…. Today, we are combining all that knowledge with modern technology to change who we are.
Genetic engineering is one of the most investigated scientific fields with endless possibilities. Fact that all living creatures are built and are functioning thanks to the information written in their DNA (or RNA when it comes to some viruses) is what makes genetic engineering that popular. Deoxyribonucleic acid (DNA) is a main constituent of the chromosomes; it contains genetic information and ability to replicate when cell is dividing. Genes are sequences of DNA, hereditary units specifically located on chromosomes, present in two copies (one copy from each of our parents) that will determine our individual characteristic after expressing. Genome is a set of all known genes within the species. What makes us so different from each other is actually a minimal redistribution of DNA nucleotides that makes us unique and unrepeatable. 99,9% of human genome is universal to all people and just 0,10% differences in our DNA will lead to distinctive characteristics each person have. We are not that different from other species as well - most biochemical processes inside living organisms are universal or at least similar. That simple fact triggered first genetic experiments, and once they started – there was no way back.
Genes are in charge for much more than just the color of our eyes. Few enzymes and couple of RNA molecules are most important participants in the complicated and jet fascinating machinery that is controlling genetic expression. Final product of genetic expression is protein. Proteins are essential for all the biochemical processes inside the organism. Most of those processes can be described as cascade where one molecule affects other and it’s a chain reaction leading at the end to a normal breading, hormone production, neurotransmitters release – in one word – having one normal and functional organism. If gene undergoes unwanted mutation and become dysfunctional – complete process will be affected and disease will develop. That’s where genetic engineering is more than useful. For example, insulin is polypeptide essential for sugar and fat metabolism. Without insulin blood sugar level can’t be regulated and result is diabetes. People with diabetes need insulin in regular daily doses but since insulin is natural protein – its production isn’t that simple. Solution comes with recombinant DNA technique. Bacterial cells contain single DNA and one or more plasmids (a circular and chromosomally independent DNA chain inside the cell) that could incorporate foreign genes and start producing the protein we want during the genetic expression phase that is happening normally in the bacterial cell. Since the genes from different species share same chemical structure, we can easily slice plasmid’s DNA at certain spot and incorporate gene that we need to multiply using specific enzymes and create expanded DNA chain that will produce one more protein in the next genetic expression round. This technique is used for multiplying a lot of proteins where most popular examples are production of the growth hormone, clothing factor VIII, recombinant hepatitis B vaccine….
Beside bacteria, plants can also be enriched with couple of foreign genes that could either enhance their endurance and tolerance toward pests and environmental conditions or increase vitamin/protein amount…
Not all genetic engineering experiments turned to be successful and useful for human kind. As with all other experiments, finding the right balance is always the key to success, but as I mention before with genetic engineering – possibilities are endless.
by nihila at 09-26-2012, 03:24 PM
3 comments
Pesticide is a chemical or biological substance that is intended to prevent or repel or destroy the pests that may damage or disturb the growth or health of living organisms which may be plants or animals. These pests include insects, rodents, fungi, weeds, nematodes, algae, etc.
These pesticides are classified on the basis their origin or structure or pests they control or the mode/ site of action.
Classification based on their origin-
There are two types – chemical pesticides and bio pesticides.
Chemical pesticides are further divided into four types based on their origin -
Organophosphate pesticides - These are the chemical substances which are produced due to reaction between phosphoric acid and alcohols. This affects the nervous system by inhibiting the action of enzyme acetyl cholinesterase (AChE). This causes irreversible blockage leading to accumulation of the enzyme which results in overstimulation of muscles. These mainly include insecticides, nerve gases, herbicides, etc.
Carbamate - These are esters of carbamic acids. The mode of action is inhibiting acetyl cholinesterase similar to that of the organophosphates but the bond formed for inhibition is less durable and thus reversible. These also include mainly of insecticides.
Organ chlorine pesticides- These are the derived from chlorinated hydrocarbons. These are endocrine disrupting agents which effect on the hormonal systems of the body, act as duplicates of the normal hormones and thus causing adverse health problems. They remain in environment for a long time by breaking down slowly and accumulating in the fat tissues of animals. A well-known example is DDT (dichloro diphenyl trichloroethane).
Pyrethroid pesticides- These are potent nuero poisons, endocrine disruptors and cause paralysis. Pyrethroids are synthetic version of pyrethrin a natural insecticide. They have similar chemical structure and similar mode of action as of pyrethrin which is obtained from chrysanthemum. These are derivatives of ketoalcoholic esters of chrysanthemic and pyrethroic acids and are more stable in sunlight than pyrethrins. These are most popular insecticides as they can easily pass through the exoskeleton of the insect. Few examples are- deltamethrin, cypermethrin, etc.
Biopesticides:
These are naturally occurring materials or derived naturally from living organisms or their metabolites, like bacteria, fungi, plants, etc. These are classified into three major groups-
Microbial pesticides- This has microorganisms acting as pest controllers like bacteria, fungi or viruses. Each of it contains specific target. Widely used are strains of Bacillus Thuringenesis or Bt and its subspecies. The mode of action generally is producing a protein that binds to the larval gut receptor which starves the larvae.
Biochemical pesticides- They are naturally occurring, nontoxic pest controllers. These include pheromones, natural plant and insect regulators, enzymes, bio repellents or attractants.
Plant incorporated protectants (PIPs) - These substances are produced by plants naturally but the gene necessary for production of pesticide is introduced into the plant through genetic engineering. The substance produced by the plant and the genetic material introduced are together defined as plant incorporated protectants (PIPs).
Classification based on their pests they control-
Insecticides- These act especially on insects.
Algaecides- control or kill growth of algae.
Herbicides – controls or kills weeds.
Bactericides - acts against bacteria.
Fungicides- acts against fungi.
Rodenticides- kills or prevents rodents i.e. rats or mice.
Larvicides – inhibits growth of larvae.
Repellents – they tend to repel pests by its taste or smell.
Desiccants- they act on plants by drying their tissues.
Ovicides – they inhibits the growth of eggs of insects and mites.
Virucides- acts against viruses.
Molluscicides – they inhibit or kill mollusc’s i. e snail’s usually disturbing growth of plants or crops.
Acaricides – they kill arachnids like mites.
Nematicides – they are tend to kill nematodes that act as parasites of plants.
Avicides – these are used to kill birds.
Moth balls- these are used to stop any damage to cloths by moth larvae or molds.
Lampricides – these are designed to target larvae of lampreys which are jawless fish like vertebrates in the river.
Piscicides – they are substances that act against fishes.
Though pesticides are designed to kill or inhibit organisms that cause damage to the crops or animals, they have harmful effects on other organisms that must not be effected and tend to pollute the environment. If used in high quantities they can be lethal sometimes. Biopesticides are used instead of chemical pesticides as the negative effects are low compared to chemical pesticides.
These pesticides are classified on the basis their origin or structure or pests they control or the mode/ site of action.
Classification based on their origin-
There are two types – chemical pesticides and bio pesticides.
Chemical pesticides are further divided into four types based on their origin -
Organophosphate pesticides - These are the chemical substances which are produced due to reaction between phosphoric acid and alcohols. This affects the nervous system by inhibiting the action of enzyme acetyl cholinesterase (AChE). This causes irreversible blockage leading to accumulation of the enzyme which results in overstimulation of muscles. These mainly include insecticides, nerve gases, herbicides, etc.
Carbamate - These are esters of carbamic acids. The mode of action is inhibiting acetyl cholinesterase similar to that of the organophosphates but the bond formed for inhibition is less durable and thus reversible. These also include mainly of insecticides.
Organ chlorine pesticides- These are the derived from chlorinated hydrocarbons. These are endocrine disrupting agents which effect on the hormonal systems of the body, act as duplicates of the normal hormones and thus causing adverse health problems. They remain in environment for a long time by breaking down slowly and accumulating in the fat tissues of animals. A well-known example is DDT (dichloro diphenyl trichloroethane).
Pyrethroid pesticides- These are potent nuero poisons, endocrine disruptors and cause paralysis. Pyrethroids are synthetic version of pyrethrin a natural insecticide. They have similar chemical structure and similar mode of action as of pyrethrin which is obtained from chrysanthemum. These are derivatives of ketoalcoholic esters of chrysanthemic and pyrethroic acids and are more stable in sunlight than pyrethrins. These are most popular insecticides as they can easily pass through the exoskeleton of the insect. Few examples are- deltamethrin, cypermethrin, etc.
Biopesticides:
These are naturally occurring materials or derived naturally from living organisms or their metabolites, like bacteria, fungi, plants, etc. These are classified into three major groups-
Microbial pesticides- This has microorganisms acting as pest controllers like bacteria, fungi or viruses. Each of it contains specific target. Widely used are strains of Bacillus Thuringenesis or Bt and its subspecies. The mode of action generally is producing a protein that binds to the larval gut receptor which starves the larvae.
Biochemical pesticides- They are naturally occurring, nontoxic pest controllers. These include pheromones, natural plant and insect regulators, enzymes, bio repellents or attractants.
Plant incorporated protectants (PIPs) - These substances are produced by plants naturally but the gene necessary for production of pesticide is introduced into the plant through genetic engineering. The substance produced by the plant and the genetic material introduced are together defined as plant incorporated protectants (PIPs).
Classification based on their pests they control-
Insecticides- These act especially on insects.
Algaecides- control or kill growth of algae.
Herbicides – controls or kills weeds.
Bactericides - acts against bacteria.
Fungicides- acts against fungi.
Rodenticides- kills or prevents rodents i.e. rats or mice.
Larvicides – inhibits growth of larvae.
Repellents – they tend to repel pests by its taste or smell.
Desiccants- they act on plants by drying their tissues.
Ovicides – they inhibits the growth of eggs of insects and mites.
Virucides- acts against viruses.
Molluscicides – they inhibit or kill mollusc’s i. e snail’s usually disturbing growth of plants or crops.
Acaricides – they kill arachnids like mites.
Nematicides – they are tend to kill nematodes that act as parasites of plants.
Avicides – these are used to kill birds.
Moth balls- these are used to stop any damage to cloths by moth larvae or molds.
Lampricides – these are designed to target larvae of lampreys which are jawless fish like vertebrates in the river.
Piscicides – they are substances that act against fishes.
Though pesticides are designed to kill or inhibit organisms that cause damage to the crops or animals, they have harmful effects on other organisms that must not be effected and tend to pollute the environment. If used in high quantities they can be lethal sometimes. Biopesticides are used instead of chemical pesticides as the negative effects are low compared to chemical pesticides.
by ExpertScie at 09-26-2012, 03:12 AM
0 comments
Health as defined is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.
It means apart from disease or infirmity many factors contribute to health. These determinants of health are control point for individuals to make their life healthy. To a large extent, factors such as our diet, healthy behavior, physical activities, state of our income, environment, education level and healthy body weight all decide our fate of healthy life. Basis such importance of these determinants in making life healthy, today many scientist and health specialist are doing inventions which are focused on investigating these determinants of heath at individual level and to develop a system that will effectively utilize these determinants to make healthy life style. In such researches, all possible defined population (Children, Adult, and Elders etc) are being considered. Today there is a need to develop a system which will implement healthy behavior by looking at ways of communicating nutrition and healthier lifestyle more effectively to the public.
The world is immensely out of balance in subject like health. It is neither secure nor stable. The WHO (World Health Organization) constitution states that only by provision of adequate health and social measures, government can fulfill their responsibilities for the health of their peoples. In other words it shares with Government that it can fulfill their responsibilities only if they work on determinants of health and social measures.
Today the question of reducing health inequities, unhealthy behavior & life style is alarming and the same can be addressed only with invention of determinants and with actions on identified issues. Today many part of world population does not comply with recommendation regarding intake of energy, saturated fat, sodium, vegetables & fruits.
Determinants of health at an individual level like health behavior, diet, and healthy body weight and any come out with new research to improve the public health throughout the world.
Today such type of research in the field of health can be done a) by sample collection of defined population (children, adult, elder etc), understanding their lifestyles, healthy behavior , their competency towards adaption of such healthy behaviors , their circumstances and awareness about healthy acts etc. b) Alignment of all collected data category wise, area wise, malnourished, over nourished, poor category , rich category etc. c) Analysis of data & field work to investigate how it can improve daily living condition , how it will help in tackling the inequitable distribution of power, money and resources, how it can help in improving communication system within public and the how best way & effectively it share the healthy habits. Today’s research should focus on measuring and understanding the top issue with statistical analysis like perito chart study, various Minitab tools etc. and how best these inventions can be translated into concrete health policy actions or how it can add to improve or to suggest findings into various health policies and overall development of system for healthy life of human beings.
Research and development in this field of health determinants is today addressing major questions like which determinant is more significantly contributing health related issue is it communication gap of healthy habits in public, lifestyle, circumstances, poverty, body weight, education etc., and more importantly the research is guiding to develop a unique system that will act on these determinants at various levels. During research work, and while doing interview of individuals for data collection, all ethical points should be taken in to consideration. This is being done to save the personal freedom and for the safety of the participants. In such case ethical approval are many times required prior to involvement of human beings in to the research.
Though only little research has been done in this field, but there has been a significant outcome & which triggers further investigation particularly to bring out the gaps and arguments in the existing research. With such research, there will be promotion of following healthy behaviors and more people engagement will take place towards healthy diet which is important determinant of health.
It means apart from disease or infirmity many factors contribute to health. These determinants of health are control point for individuals to make their life healthy. To a large extent, factors such as our diet, healthy behavior, physical activities, state of our income, environment, education level and healthy body weight all decide our fate of healthy life. Basis such importance of these determinants in making life healthy, today many scientist and health specialist are doing inventions which are focused on investigating these determinants of heath at individual level and to develop a system that will effectively utilize these determinants to make healthy life style. In such researches, all possible defined population (Children, Adult, and Elders etc) are being considered. Today there is a need to develop a system which will implement healthy behavior by looking at ways of communicating nutrition and healthier lifestyle more effectively to the public.
The world is immensely out of balance in subject like health. It is neither secure nor stable. The WHO (World Health Organization) constitution states that only by provision of adequate health and social measures, government can fulfill their responsibilities for the health of their peoples. In other words it shares with Government that it can fulfill their responsibilities only if they work on determinants of health and social measures.
Today the question of reducing health inequities, unhealthy behavior & life style is alarming and the same can be addressed only with invention of determinants and with actions on identified issues. Today many part of world population does not comply with recommendation regarding intake of energy, saturated fat, sodium, vegetables & fruits.
Determinants of health at an individual level like health behavior, diet, and healthy body weight and any come out with new research to improve the public health throughout the world.
Today such type of research in the field of health can be done a) by sample collection of defined population (children, adult, elder etc), understanding their lifestyles, healthy behavior , their competency towards adaption of such healthy behaviors , their circumstances and awareness about healthy acts etc. b) Alignment of all collected data category wise, area wise, malnourished, over nourished, poor category , rich category etc. c) Analysis of data & field work to investigate how it can improve daily living condition , how it will help in tackling the inequitable distribution of power, money and resources, how it can help in improving communication system within public and the how best way & effectively it share the healthy habits. Today’s research should focus on measuring and understanding the top issue with statistical analysis like perito chart study, various Minitab tools etc. and how best these inventions can be translated into concrete health policy actions or how it can add to improve or to suggest findings into various health policies and overall development of system for healthy life of human beings.
Research and development in this field of health determinants is today addressing major questions like which determinant is more significantly contributing health related issue is it communication gap of healthy habits in public, lifestyle, circumstances, poverty, body weight, education etc., and more importantly the research is guiding to develop a unique system that will act on these determinants at various levels. During research work, and while doing interview of individuals for data collection, all ethical points should be taken in to consideration. This is being done to save the personal freedom and for the safety of the participants. In such case ethical approval are many times required prior to involvement of human beings in to the research.
Though only little research has been done in this field, but there has been a significant outcome & which triggers further investigation particularly to bring out the gaps and arguments in the existing research. With such research, there will be promotion of following healthy behaviors and more people engagement will take place towards healthy diet which is important determinant of health.
by ExpertScie at 09-26-2012, 02:46 AM
0 comments
One could wonder how so huge demand of vaccines is being meeting by manufacturers in short span of time. The answer is biotechnology. Today in the field of biotechnology, many such research and development is done which is helping mankind in all ways. One such technique of propagation of required cell is called as cell culture. This technique is helping manufacturer to meet short timelines for production of large scale vaccines. Cell culture is nothing but the growth of cells in controlled condition outside their natural environment is known as cell culture. The culturing of cell generally takes place in multi-cellular eukaryotes like animals and plants. But much culture of bacteria, fungus, plants and other microbes are being maintained and propagated from past. Thus the concept of maintaining the cell line or cell culture came into picture and thus today became the developed and necessary part of many industries and medical field.
There are many applications of cell culture. The main use of cell culture is done in manufacture of viral vaccines. Apart from this, cell culture is used in synthesis of hormones, enzymes and many such biotechnology products. In manufacturing of viral vaccines, mass cultivation of cell line is done. This cell cultures are then used to cultivate viruses which are intra cellular obligatory parasites. Therefore today one cannot think to prepare viral vaccines without the use of cell cultures. Immunobiologicals like monoclonal antibodies, lymphokines, interleukins, and other anticancer agents are prepared with the help of animal cell culture technique. The complex and important protein like erythropoietin is produced using rDNA in bacterial cell culture. Today with the use of animal cells all over the world, the demand is increasing as well as the cost of animal’s cell is high. Therefore plant cells and insect cells are being used and tried for the alternative to animal cells. Further single embryonic cell and other somatic cells of embryo are being used as source for transfer of gene of interest. All these useful products are today available due to the contribution of cell culture technique which is today a important part of biotechnology.
With the growth in cell culture technology, pure form of viral vaccines was being made successfully. Cell culture is related to tissue culture in which propagation of plants is done. The first injectable polio vaccine was successfully developed by Scientist Jonas Salk. He used cell culture technique and had done mass production of viral vaccines today being used against deadly polio disease. With further development in cell culture studies, Scientist John Franklin Enders and et al discovered a new method of growing viruses in kidney cell of money. For this work he was awarded Nobel Prize. Thus he saved many lives from being infected by viral diseases through vaccination which was possible only using cell culture technique.
The technique of cell culture employs few steps 1) Isolation of cells, 2) Maintenance of isolated cell in culture,3) Manipulation of culture cells & 4 ) Passaging etc., For isolation , cells are first purified from sources like blood. Mononuclear cells are isolated with enzymatic digestion from soft tissues. In such case, the enzyme like collagenase, pronase and trypsin is utilized. The enzyme’s active site acts on the substrate and thus breaks down the cellular matrix. One other famous method is explants culture method. In this method, the tissues are cultured in growth media. The cells which grow are isolated easily are available for culture.
Cells cultures are maintained under controlled environmental conditions which are favorable for their growth. The necessary temperature and humidity is provided. The 37 °C is many times used and 4-5 % CO2 is maintained for cells of mammals. All this is maintained in incubators. Another factors like pH, concentration of nutrients, growth factors, osmotic balancing is being taken care of. The other factor like density of plating is also considered. In which number of cells per culture volume is considered to avoid contamination and to enrich the culture properly. Contamination is major issue and can be tackled with the help of clean rooms and providing HEPA filters where the activity is done. Manipulation and passaging of culture is done as per the requirement of quantity of cell culture. Passaging is nothing but sub-culturing in which small number of cell is transferred into new container or vessel. Thus a new cycle of cell culturing is started. Thus today many biotechnology and medicinal products are prepared only with the help of this useful and important technique of cell culturing.
There are many applications of cell culture. The main use of cell culture is done in manufacture of viral vaccines. Apart from this, cell culture is used in synthesis of hormones, enzymes and many such biotechnology products. In manufacturing of viral vaccines, mass cultivation of cell line is done. This cell cultures are then used to cultivate viruses which are intra cellular obligatory parasites. Therefore today one cannot think to prepare viral vaccines without the use of cell cultures. Immunobiologicals like monoclonal antibodies, lymphokines, interleukins, and other anticancer agents are prepared with the help of animal cell culture technique. The complex and important protein like erythropoietin is produced using rDNA in bacterial cell culture. Today with the use of animal cells all over the world, the demand is increasing as well as the cost of animal’s cell is high. Therefore plant cells and insect cells are being used and tried for the alternative to animal cells. Further single embryonic cell and other somatic cells of embryo are being used as source for transfer of gene of interest. All these useful products are today available due to the contribution of cell culture technique which is today a important part of biotechnology.
With the growth in cell culture technology, pure form of viral vaccines was being made successfully. Cell culture is related to tissue culture in which propagation of plants is done. The first injectable polio vaccine was successfully developed by Scientist Jonas Salk. He used cell culture technique and had done mass production of viral vaccines today being used against deadly polio disease. With further development in cell culture studies, Scientist John Franklin Enders and et al discovered a new method of growing viruses in kidney cell of money. For this work he was awarded Nobel Prize. Thus he saved many lives from being infected by viral diseases through vaccination which was possible only using cell culture technique.
The technique of cell culture employs few steps 1) Isolation of cells, 2) Maintenance of isolated cell in culture,3) Manipulation of culture cells & 4 ) Passaging etc., For isolation , cells are first purified from sources like blood. Mononuclear cells are isolated with enzymatic digestion from soft tissues. In such case, the enzyme like collagenase, pronase and trypsin is utilized. The enzyme’s active site acts on the substrate and thus breaks down the cellular matrix. One other famous method is explants culture method. In this method, the tissues are cultured in growth media. The cells which grow are isolated easily are available for culture.
Cells cultures are maintained under controlled environmental conditions which are favorable for their growth. The necessary temperature and humidity is provided. The 37 °C is many times used and 4-5 % CO2 is maintained for cells of mammals. All this is maintained in incubators. Another factors like pH, concentration of nutrients, growth factors, osmotic balancing is being taken care of. The other factor like density of plating is also considered. In which number of cells per culture volume is considered to avoid contamination and to enrich the culture properly. Contamination is major issue and can be tackled with the help of clean rooms and providing HEPA filters where the activity is done. Manipulation and passaging of culture is done as per the requirement of quantity of cell culture. Passaging is nothing but sub-culturing in which small number of cell is transferred into new container or vessel. Thus a new cycle of cell culturing is started. Thus today many biotechnology and medicinal products are prepared only with the help of this useful and important technique of cell culturing.