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Koleksi stem-cells-1

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  • Stem cells are different from other cells of the body in that they have the ability to differentiate into other cell/tissue types. This ability allows them to replace cells that have died. With this ability, they have been used to replace defective cells/tissues in patients who have certain diseases or defects.
  • Molecular biology and genetics research has experienced phenomenal gains within the last two decades. Our ability to learn about and alter cells through genetic manipulation has expanded rapidly and will continue to do so at an increasing pace in coming years. However, just because we can do all this advanced science doesn't mean that we should. Curing human diseases is a wonderful goal. However, we should not commit moral evils to accomplish moral good. This presentation examines both the science and morality of using these new scientific tools.
  • The topics to be covered in this presentation are listed above. First topic: What are stem cells?
  • Stem cells can be classified into three broad categories, based on their ability to differentiate. Totipotent stem cells are found only in early embryos. Each cell can form a complete organism (e.g., identical twins). Pluripotent stem cells exist in the undifferentiated inner cell mass of the blastocyst and can form any of the over 200 different cell types found in the body. Multipotent stem cells are derived from fetal tissue, cord blood and adult stem cells. Although their ability to differentiate is more limited than pluripotent stem cells, they already have a track record of success in cell-based therapies. Here is a current list of the sources of stem cells: Embryonic stem cells - are harvested from the inner cell mass of the blastocyst seven to ten days after fertilization. Fetal stem cells - are taken from the germline tissues that will make up the gonads of aborted fetuses. Umbilical cord stem cells - Umbilical cord blood contains stem cells similar to those found in bone marrow. Placenta derived stem cells - up to ten times as many stem cells can be harvested from a placenta as from cord blood. Adult stem cells - Many adult tissues contain stem cells that can be isolated.
  • The topics to be covered in this presentation are listed above. First topic: What are stem cells?
  • Stem cells can be classified into three broad categories, based on their ability to differentiate. Totipotent stem cells are found only in early embryos. Each cell can form a complete organism (e.g., identical twins). Pluripotent stem cells exist in the undifferentiated inner cell mass of the blastocyst and can form any of the over 200 different cell types found in the body. Multipotent stem cells are derived from fetal tissue, cord blood and adult stem cells. Although their ability to differentiate is more limited than pluripotent stem cells, they already have a track record of success in cell-based therapies. Here is a current list of the sources of stem cells: Embryonic stem cells - are harvested from the inner cell mass of the blastocyst seven to ten days after fertilization. Fetal stem cells - are taken from the germline tissues that will make up the gonads of aborted fetuses. Umbilical cord stem cells - Umbilical cord blood contains stem cells similar to those found in bone marrow. Placenta derived stem cells - up to ten times as many stem cells can be harvested from a placenta as from cord blood. Adult stem cells - Many adult tissues contain stem cells that can be isolated.
  • The early stages of embryogenesis are the point at which embryonic stem cell lines are derived. The fertilized egg (day 1) undergoes cell division to form a 2-cell embryo, followed by 4-cell, etc. until a ball of cells is formed by the fourth day. The ball becomes hollow, forming the blastocyst. This is the stage at which pluripotent embryonic stem cell lines are generated. Following the blastocyst stage, the tissues of the embryo start to form and the cells become multipotent.
  • The inner cell mass (the part that would form the fetus) of the embryo is isolated and disrupted to form embryonic cell lines. This process destroys the embryo. Under special culture conditions, the cells of the embryonic lines can be coaxed to form certain kinds of differentiated cell types. In theory, these differentiated cells could be used to repair or replace defective cells or tissues.
  • Stem cells from bone marrow form a number of cell types of the immune and circulatory system. These stem cells have been used to cure diseases since the 1960's.
  • In theory, stem cell technology could be used to produce replaceable tissues or organs. Defective tissues/organs could be repaired using healthy cells. It would also be possible to genetically engineer stem cells to accomplish activities that they would not ordinarily be programmed to do. Part of this engineering could involve the delivery of chemotherapeutic agents for treatment of cancers and tumors.
  • Adult stem cells have shown great promise in many published studies. These cells have shown the potential to form many different kinds of cell types and tissues, including functional hepatocyte-like (liver) cells. Such cells might be useful in repairing organs ravaged by diseases. References Tremain, N., et al., “MicroSAGE Analysis of 2,353 Expressed Genes in a Single-Cell Derived Colony of Undifferentiated Human Mesenchymal Stem Cells Reveals mRNAs of Multiple Cell Lineages,” Stem Cells 19: 408-418 (2001). Schwartz, R. E., et al., “Multipotent adult progenitor cells from bone marrow differentiate into functional hepatocyte-like cells,” Journal of Clinical Investigation 109: 1291-1302 (2002).
  • Adult neural stem cells have been shown to migrate extensively in the brain of rats following injection. Adult stem cells have been isolated from many different kinds of tissues, although they are present in small numbers. Reference David A. Prentice. 2004. Monitoring Stem Cell Research (www.bioethics.gov) Appendix K. “Adult Stem Cells”
  • The first human cloned embryos were not produced until 2001, when a private company, Advanced Cell Technology, produced 6-cell embryos. However, the first cloned human blastocyst was not produced until 2004 by a group in Korea. However, subsequently, it was found that much of the information in the publication was fabricated and the paper was officially withdrawn in January, 2006. Also, contrary to the claims in the paper, not hundreds of oocytes, but over 2000 were used, although no cell lines could be established.1 A subsequent publication by Hwang et al. in 2005 was also found to have been fabricated by intentionally submitting duplicate patient samples in place of patient samples and cloned cells. Both papers were withdrawn by the journal Science . More info is available from the Science website. Dennis Normile, Gretchen Vogel and Jennifer Couzin. 2006. South Korean Team's Remaining Human Stem Cell Claim Demolished. Science NOW Daily News.
  • The use of cloned human embryonic stem cells for cell-based therapies has the advantage of producing tissues with perfect compatibility for the patient. However, there are problems, even with the most successful study done to date. First, only 25% of the cloned oocytes became embryos. This rate is much higher than previous studies, but still requires a number of attempts. Only 5% of those 25% survived to become a cell line. This equates with a 1% success rate. Obviously, harvesting 100 embryos to achieve one success is problematic. In the study, the genetic donor was the same as the egg donor. This method probably increased the success of the cloning, but obviously would not work for males, who have no eggs! In addition the cost of individual cloning therapy would be high, due to the need to develop a cell line for each individual patient.
  • In order to be used clinically, human embryonic stem cells must be differentiated prior to use in patients. Undifferentiated stem cells could produce tumors and multiply unchecked within a patient, causing more problems than providing appropriate therapy. It is uncertain if conditions can be defined such that all embryonic stem cells differentiate into the correct cell type prior to therapeutic use. Complications caused by undifferentiated cells might not be discovered until years after the first clinical trials are begun. This differentiation problem is acknowledged on the International Society for Stem Cell Research website: "Scientists are still working on developing proper conditions to differentiate embryonic stem cells into specialized cells. As embryonic stem cells grow very fast, scientists must be very careful in fully differentiating them into specialized cells. Otherwise, any remaining embryonic stem cells can grow uncontrolled and form tumors." 1 Recently, three established stem cell lines were shown to exhibit abnormalities in chromosome number and structure. 2, 3 Obviously, stem cell lines must be checked periodically to make sure the cells do not become abnormal during continued culture. The use of abnormal cells in treatment of patients could result in indeterminate complications. References "Frequently Asked Questions." International Society for Stem Cell Research. Draper, J.S., et al., "Recurrent gain of chromosomes 17q and 12 in cultured human embryonic stem cells," Nature Biotechnology December 7, 2003, advance online publication. C. Cowan et al. 2004. Derivation of Embryonic Stem-Cell Lines from Human Blastocysts. New England Journal of Medicine 350: 1353-1356.
  • Undifferentiated stem cells could produce tumors and multiply unchecked within a patient, causing more problems than providing appropriate therapy. According to a recent article ion the New England Journal of Medicine : "There are still many hurdles to clear before embryonic stem cells can be used therapeutically. For example, because undifferentiated embryonic stem cells can form tumors after transplantation in histocompatible animals, it is important to determine an appropriate state of differentiation before transplantation. Differentiation protocols for many cell types have yet to be established. Targeting the differentiated cells to the appropriate organ and the appropriate part of the organ is also a challenge.” Harvard scientists reported in the Proceedings of the National Academy of Sciences that five out of the 19 mice injected with embryonic stem cells developed tumors and died." 2 Stem cell lines will suffer the same tissue rejection problems as adult transplants. Once differentiated, these cells will express the HLA tissue antigens programmed by their parental DNA. These antigens must match those of the recipient or else tissue rejection will occur. An admission of the problem of immune rejection can be found from The Scientist : "[W]ithin the [embryonic stem cell] research community, realism has overtaken early euphoria as scientists realize the difficulty of harnessing ESCs safely and effectively for clinical applications. After earlier papers in 2000 and 2001 identified some possibilities, research continued to highlight the tasks that lie ahead in steering cell differentiation and avoiding side effects, such as immune rejection and tumorigenesis.” 1 References E. Phimister and J. Drazen. 2004. Two Fillips for Human Embryonic Stem Cells.” New England Journal of Medicine 350: 1351-1352. Bjorklund, L. M., R. Sanchez-Pernaute, et al. 2002 "Embryonic stem cells develop into functional dopaminergic neurons after transplantation in a Parkinson rat model." Proceedings of the National Academy of Sciences 99: 2344-2349. Hunter, Philip. 2003. Differentiating Hope from Embryonic Stem Cells. The Scientist 17: 31.
  • Like all immortal cell lines, embryonic stem cell lines must be protected and checked for contamination with viruses, bacteria, fungi, and Mycoplasma . The use of infected lines in patient treatment could have devastating effects. Many embryonic stem cell lines are grown using mouse feeder cells. The mouse cells help the embryonic lines to grow, but pose risks for transplantation due to compatibility problems in human bodies. 1 Reference Kennedy, Donald. 2003. Stem Cells: Still Here, Still Waiting. Science 300: 865.
  • Embryonic stem cell proponents claim that a fertilized egg is just a single cell - like any other cell of the human body and is only "potential life". However, this single cell is alive by any biological definition of life and defines the beginning of each new human being. This single cell is unique from both the father's and mother's cells, so it cannot be defined as just an ordinary cell.
  • Embryonic stem cell proponents claim that embryos are only "potential life". Most will fail to be born under natural conditions. It is known that one third of implanted embryos die before birth. 1 However, there are third-world countries in which 25% of children under the age of five die. 2 If we base potential life upon early death, then these children could also be considered as only "potential adults." Using this "logic" these children could be sacrificed for research. References Ellison, P. T. 2001. On Fertile Ground . Harvard University Press. Chapter 2 “Surviving the First Cut.” World Development Indicators. 2000. http://www.etext.org/Politics/MIM/faq/worldbankoninfantmortality.pdf
  • Transcript

    • 1. EDITED BY ; PROF.DR.PRATIWITS,MS 08/31/13STEM CELLS -PROF PRATIWI 20121 KOLEKSI DAN APLIKASI STEM SEL
    • 2. 08/31/132 STEM CELLS -PROF PRATIWI 2012
    • 3. Stem Cell – Definition 08/31/13STEM CELLS -PROF PRATIWI 20123 A cell that has the ability to continuously divide and differentiate (develop) into various other kind(s) of cells/tissues
    • 4. Introduction 08/31/13STEM CELLS -PROF PRATIWI 20124 Can we vs. should we Dramatic advances of modern molecular genetics Should we ask the morality questions before attempting the “can we” questions?
    • 5. Stem Cell/Cloning Topics 08/31/13STEM CELLS -PROF PRATIWI 20125 What are stem cells? History of stem cell/cloning research Possible uses of the technology Current status/knowledge Questions and known problems Legal considerations Politics Moral considerations
    • 6. Kinds of Stem Cells Stem cell type Description Examples Totipotent Each cell can develop into a new individual Cells from early (1-3 days) embryos Pluripotent Cells can form any (over 200) cell types Some cells of blastocyst (5 to 14 days) Multipotent Cells differentiated, but can form a number of other tissues Fetal tissue, cord blood, and adult stem cells 08/31/13STEM CELLS -PROF PRATIWI 20126 Totipotent Pluripotent Multipotent
    • 7. Stem Cell/Cloning Topics 08/31/13STEM CELLS -PROF PRATIWI 20127 What are stem cells? History of stem cell/cloning research Possible uses of the technology Current status/knowledge Questions and known problems Legal considerations Politics Moral considerations
    • 8. Kinds of Stem Cells Stem cell type Description Examples Totipotent Each cell can develop into a new individual Cells from early (1-3 days) embryos Pluripotent Cells can form any (over 200) cell types Some cells of blastocyst (5 to 14 days) Multipotent Cells differentiated, but can form a number of other tissues Fetal tissue, cord blood, and adult stem cells 08/31/13STEM CELLS -PROF PRATIWI 20128 Totipotent Pluripotent Multipotent
    • 9. Stages of Embryogenesis 08/31/13STEM CELLS -PROF PRATIWI 20129 Day 1 Fertilized egg Day 2 2-cell embryo Day 3-4 Multi-cell embryo Day 5-6 BlastocystDay 11-14 Tissue Differentiation
    • 10. Derivation and Use of Embryonic Stem Cell Lines 08/31/13STEM CELLS -PROF PRATIWI 201210 Isolate inner cell mass (destroys embryo) Heart muscleKidney Liver “Special sauce” (largely unknown) Day 5-6 Blastocyst Inner cells (forms fetus) Outer cells (forms placenta) Heart repaired Culture cells
    • 11. Bone Marrow Stem Cells 08/31/13STEM CELLS -PROF PRATIWI 201211
    • 12. Possible Uses of Stem Cell Technology 08/31/13STEM CELLS -PROF PRATIWI 201212 Replaceable tissues/organs Repair of defective cell types Delivery of genetic therapies Delivery chemotherapeutic agents
    • 13. Early Successes – Adult Stem Cells 08/31/13STEM CELLS -PROF PRATIWI 201213 Human mesenchymal stem cells turned on genes found in bone, cartilage, adipose, muscle, hematopoiesis-supporting stromal, endothelial, and neuronal cells. Multipotent adult progenitor cells have been shown to differentiate into functional, hepatocyte-like cells.
    • 14. Early Successes – Adult Stem Cells 08/31/13STEM CELLS -PROF PRATIWI 201214 Human neural stem cells can migrate extensively in the brain after injection. Adult stem cells have been isolated from amniotic fluid, peripheral blood, umbilical cord blood, umbilical cord, brain tissue, muscle, liver, pancreas, cornea, salivary gland, skin, tendon, heart, cartilage, thymus, dental pulp, and adipose tissue.
    • 15. Early Successes – Human Cloning 08/31/13STEM CELLS -PROF PRATIWI 201215 2001 – First cloned human embryos (only to six cell stage) created by Advanced Cell Technology (USA) 2004* – Claim of first human cloned blastocyst created and a cell line established (Korea) – later proved to be fraudulent *Hwang, W.S., et al. 2004. Evidence of a Pluripotent Human Embryonic Stem Cell Line Derived from a Cloned Blastocyst. Science 303: 1669-1674.
    • 16. Cloned Embryonic Stem Cells – Advantages/Problems 08/31/13STEM CELLS -PROF PRATIWI 201216 Advantages No rejection “Prefect match” Problems Only 10% of cloned oocytes became embryos 0% (0 out of 2061) survived to become a cell line Genetic donor was same as egg donor (i.e., won’t work for males!) Cost is high (health insurance probably won't pay)
    • 17. Challenges to Stem Cell/Cloning Research 08/31/13STEM CELLS -PROF PRATIWI 201217 Stem cells need to be differentiated to the appropriate cell type(s) before they can be used clinically. Recently, abnormalities in chromosome number and structure were found in three human ESC lines.
    • 18. Challenges to Stem Cell/Cloning Research 08/31/13STEM CELLS -PROF PRATIWI 201218 Stem cell development or proliferation must be controlled once placed into patients. Possibility of rejection of stem cell transplants as foreign tissues is very high.
    • 19. Challenges to Stem Cell/Cloning Research 08/31/13STEM CELLS -PROF PRATIWI 201219 Contamination by viruses, bacteria, fungi, and Mycoplasma possible. The use of mouse “feeder” cells to grow ESC could result in problems due to xenotransplantation (complicating FDA requirements for clinical use).
    • 20. At Conception, It Is Only a Single Cell 08/31/13STEM CELLS -PROF PRATIWI 201220 Claim: Fertilized eggs are single cells, like blood cells or other parts of the body Rebuttal: This single cell is unique from both the father’s and mother’s cells and is the beginning of every new human being
    • 21. Only a Small Percentage of Embryos Implant 08/31/13STEM CELLS -PROF PRATIWI 201221 Claim: Embryos are only potential life. Most do not result in births Rebuttal: 25-33% of women become pregnant in the first month 33% of implanted embryos die before birth There are countries in which over 25% of children die before age 5. Should we allow killing of children?
    • 22. Unexpected Phenotypes Phenotype more severe than expected: - Early lethal - Lack of inductive signals Phenotype less severe than expected: - Incomplete gene disruption - Genetic redundancy - Functional redundancy (compensation) 08/31/1322 STEM CELLS -PROF PRATIWI 2012
    • 23. Applied research - DNA Applied research arising out of the discovery of DNA includes disease diagnosis, drug development, gene therapy and, more recently, genetically-modified organisms 08/31/1323 STEM CELLS -PROF PRATIWI 2012
    • 24. 08/31/13STEM CELLS -PROF PRATIWI 201224
    • 25. 08/31/13STEM CELLS -PROF PRATIWI 201225
    • 26. 08/31/13STEM CELLS -PROF PRATIWI 201226
    • 27. 08/31/1327 STEM CELLS -PROF PRATIWI 2012
    • 28. Transgenic Animals and Products Mice- transgenetic mice have been used in several ways. One of the best known is to produce human antibodies. Cattle- are used to control disease such as mastitis in dairy cows. 08/31/1328 STEM CELLS -PROF PRATIWI 2012
    • 29. Methods of creating transgenetic animals Step One- collect embryos With proper stimulation far more embryos can be obtained than would be the natural result of the reproductive process. 08/31/1329 STEM CELLS -PROF PRATIWI 2012
    • 30. Methods of creating transgenetic animals Step Two- Inject embyros. A pro nucleus is the haploid nucleus of the sperm or ovum that have united in fertilization to form a zygote. 08/31/1330 STEM CELLS -PROF PRATIWI 2012
    • 31. Embryo Transfer Embryo transfer is the harvesting of fertilized ova from a donor and implanting them into a recipient. The harvested embyros are transferred to a recipient. 08/31/1331 STEM CELLS -PROF PRATIWI 2012
    • 32. Clone Birth Defects • Cloned offspring often suffer from large offspring syndrome, where the clone and the placenta that nourished it are unusually large. • Cloned offspring often have serious inexplicable respiratory or circulatory problems, which causes them to die soon after birth. • Clones tend to have weakened immune systems and sometimes suffer from total immune system failure. • Very few clones actually survive to adulthood. 08/31/1332 STEM CELLS -PROF PRATIWI 2012
    • 33. 08/31/13STEM CELLS -PROF PRATIWI 201233 Clones appear to age faster than normal.  Clones experience problems associated with old age, such as arthritis, while they are still young.  This may be due to the fact that clones have shorter telomeres
    • 34. Transgenic Animals:  Animal biotechnology is the field to engineer transgenic animals, i.e., animals that carry genes from other species.  The technology has already produced transgenic animals such as mice, rats, rabbits, pigs, sheep, and cows. 08/31/1334 STEM CELLS -PROF PRATIWI 2012
    • 35. Transgenic Animals Definition:  An organism (typically a mouse) that is engineered to carry a foreign gene, or transgene of choicem as part of its own genetic material. 08/31/1335 STEM CELLS -PROF PRATIWI 2012
    • 36. Transgenic Animals Purpose:  These animals are very useful for delineating the function of newly discovered genes as well as for producing useful proteins in large animals. 08/31/1336 STEM CELLS -PROF PRATIWI 2012
    • 37. Transgenic Animals In some of the eggs, the genetic material integrates at a random site on a chromosome and so becomes part of the mouse cell's genetic material the animal resulting from that egg will therefore carry that gene and so is referred to as a "transgenic animal". 08/31/1337 STEM CELLS -PROF PRATIWI 2012
    • 38. What is a transgenic animal?  A transgenic animal is one whose genome has been changed to carry genes from other species.  For example, an embryo can have an extra, functioning gene from another source artificially introduced into it, or a gene introduced which can knock out the functioning of another particular gene in the embryo. 08/31/1338 STEM CELLS -PROF PRATIWI 2012
    • 39. Transgenic Animals  Animals that have their DNA manipulated in this way are known as transgenic animals.  Transgenic animals are useful as disease models and producers of substances for human welfare. 08/31/1339 STEM CELLS -PROF PRATIWI 2012
    • 40. Why are these animals being produced?  Some transgenic animals are produced for specific economic traits.  E.g., transgenic cattle were created to produce milk containing particular human proteins, which may help in the treatment of human emphysema. 08/31/1340 STEM CELLS -PROF PRATIWI 2012
    • 41. How are transgenic animals produced? DNA microinjection Introducing the transgene DNA directly into the zygote at an early stage of development.  No vector required. Retrovirus-mediated gene transfer:  Infecting mouse embryo with a retrovirus which carry the new gene.  Using virus as a vector . 08/31/1341 STEM CELLS -PROF PRATIWI 2012
    • 42. Embryonic stem cell-mediated gene transfer  The blastocyst (inner layer of a fertilized egg) is harvested and mixed with recombinant DNA and inserted back in the blastocyst. Sperm-mediated transfer  Use of “Linker protein" to attach DNA to sperm which transfer the new DNA during fertilization. Gene gun 08/31/1342 STEM CELLS -PROF PRATIWI 2012
    • 43. Embryonic stem cell-mediated gene transfer This method involves:  Isolation of totipotent stem cells (stem cells that can develop into any type of specialized cell) from embryos.  The desired gene is inserted into these cells.  Cells containing the desired DNA are incorporated into the host's embryo. 08/31/1343 STEM CELLS -PROF PRATIWI 2012
    • 44. First Breeding Pair: Fertile male + superovulated female Fertile male Superovulated female = immature female induced to superovulate  Pregnant mare’s serum (=FSH) on day 1  Human Chorionic Gonadotropin (=LH) on day 3 Mated on day 3 Fertilized oocytes microinjected on day 4 with foreign DNA construct. Microinjected oocytes are transferred to the oviducts of surrogate mothers at end of day 4. Procedure for Producing Transgenic Mice 08/31/1344 STEM CELLS -PROF PRATIWI 2012
    • 45. Second breeding pair: Sterile male + surrogate mother Sterile male produced through vasectomy Surrogate mother must mate to be suitable recipient of injected eggs Mated on day 3 Microinjected oocytes from first breeding pair are transferred to oviducts on day 4 Embryos implant in uterine wall and are born 19 days later. Southern blotting techniques confirm presence and copy number of transgenes. Procedure for Producing Transgenic Mice 08/31/1345 STEM CELLS -PROF PRATIWI 2012
    • 46. Third breeding pair: Foster parents Fertile male + female mated to give birth on same day surrogate mother Serves as foster parent if caesarian section is required for surrogate mother Procedure for Producing Transgenic Mice 08/31/1346 STEM CELLS -PROF PRATIWI 2012
    • 47. 08/31/1347 STEM CELLS -PROF PRATIWI 2012
    • 48. Totipotent and pluripotent cells Totipotent = meaning that its potential is total. pluripotent = they can give rise to many types of cells but not all types of cells (no fetus developed). isolated directly from the inner cell mass of embryos at the blastocyst stage. (IVF-IT surplus embryos in case of humans) 08/31/1348 STEM CELLS -PROF PRATIWI 2012
    • 49. More about stem cells Embryonic stem cells Adult stem cells Truly pluripotential More restricted pattern of differentiation medical gain without ethical pain several countries have sanctioned deriving human ES-cell lines from ‘surplus’ embryos created through in vitro fertilization although several human ES-cell lines have been made, they will not be immunologically compatible with most patients who require cell transplants. 08/31/1349 STEM CELLS -PROF PRATIWI 2012
    • 50. Transgenic mice The growth hormone gene has been engineered to be expressed at high levels in animals. The result: BIG ANIMALS metallothionein promoter regulated as heavy metals Mice fed heavy metals are 2-3 times larger 08/31/1350 STEM CELLS -PROF PRATIWI 2012
    • 51. Studies Utilizing Transgenic Mice “Pharm” animals (transgenic livestock) Bioreactors whose cells have been engineered to synthesize marketable proteins DNA constructs contain desired gene and appropriate regulatory sequences (tissue-specific promoters) More economical than producing desired proteins in cell culture 08/31/1351 STEM CELLS -PROF PRATIWI 2012
    • 52. Antifreeze gene promoter with GH transgene in atlantic salmon GH gene comes from larger salmon 08/31/1352 STEM CELLS -PROF PRATIWI 2012
    • 53. Wild and domestic trout respond differently to overproduction of growth hormone. So in some cases, GH not effective. 08/31/1353 STEM CELLS -PROF PRATIWI 2012
    • 54. Improving Agricultural Products with Transgenics Transgenic technology holds great potential in agriculture, medicine, and industry  The benefits of these animals to human welfare can be grouped into areas:  Agriculture  Medicine  Industry 08/31/1354 STEM CELLS -PROF PRATIWI 2012
    • 55. 1. Agricultural Applications A) Breeding  Traditional cross breeding have been used for ages to create chickens, cows, pigs etc.  Farmers have always used selective breeding to produce animals that exhibit desired traits (e.g., increased milk production, high growth rate).  Traditional breeding is a time-consuming, difficult task. 08/31/1355 STEM CELLS -PROF PRATIWI 2012
    • 56.  Researchers have now used gene transfer to improve the productivity of livestock.  Now it is possible to develop traits in animals in a shorter time and with more precision.  It also offers farmers an easy way to increase yields. 08/31/1356 STEM CELLS -PROF PRATIWI 2012
    • 57.  Scientists can improve the size of livestock genetically.  Transgenic cows exist that produce more milk or milk with less lactose or cholesterol.  Transgenic cows have been used to produce milk which are richer in proteins and lower in fat. 08/31/1357 STEM CELLS -PROF PRATIWI 2012
    • 58. B) Quality  Herman, a transgenic bull carries a human gene for Lactoferrin (gene responsible for higher iron content)  Pigs and cattle that have more meat on them.  Sheep that grow more wool.  Eggs can be made healthier with high quality protein. 08/31/1358 STEM CELLS -PROF PRATIWI 2012
    • 59. C) Disease resistance  Disease-resistant livestock is not a reality just yet.  But there has been improvement in disease reduction in animals.  The Foot- and- Mouth disease in England in 2000 led to destruction of herds of cattle, sheep and goat. 08/31/1359 STEM CELLS -PROF PRATIWI 2012
    • 60.  Scientists are attempting to produce disease-resistant animals, such as influenza- resistant pigs, but a very limited number of genes are currently known to be responsible for resistance to diseases in farm animals.  Transgenic disease protection promises a long term cost effective method of battling animal diseases. 08/31/1360 STEM CELLS -PROF PRATIWI 2012
    • 61. 2. Medical Applications A) Xenotransplantation  Transplant organs may soon come from transgenic animals. 08/31/1361 STEM CELLS -PROF PRATIWI 2012
    • 62. B) Nutritional supplements and pharmaceuticals  Products such as insulin, growth hormone, and blood anti-clotting factors may soon be or have already been obtained from the milk of transgenic cows, sheep, or goats.  The first transgenic cow (Rosie ) produced human protein-enriched milk at 2.4 grams per liter. 08/31/1362 STEM CELLS -PROF PRATIWI 2012
    • 63.  This transgenic milk is a more nutritionally balanced product than natural milk and could be given to babies or the elderly with special nutritional or digestive needs.  A transgenic cow exists that produces a substance to help human red cells grow. 08/31/1363 STEM CELLS -PROF PRATIWI 2012
    • 64. C) Human gene therapy  Human gene therapy involves adding a normal copy of a gene (transgene) to the genome of a person carrying defective copies of the gene.  Finland produced a calf with a gene that makes the substance that promotes the growth of red cells in humans. 08/31/1364 STEM CELLS -PROF PRATIWI 2012
    • 65. 3. Industrial Applications :  By extracting polymer strands from the milk and weaving them into thread, the scientists can create a light, tough, flexible material that could be used in such applications as military uniforms, medical microsutures, and tennis racket strings.  Biosteel is an extraordinary new product that may be soon used in bullet proof vests and in suture silk for stitching wounds.  Animals have been used as “Bioreactors” to produce proteins. Genes for desired proteins are introduced via transgenics to the target cells . 08/31/1365 STEM CELLS -PROF PRATIWI 2012
    • 66. :  The target cells are cloned and several such cells are raised into adults.  These adults may produce milk or eggs (due to the presence of introduced gene rich in desired protein).  Toxicity-sensitive transgenic animals have been produced for chemical safety testing.  Microorganisms have been engineered to produce a wide variety of proteins, which in turn can produce enzymes that can speed up industrial chemical reactions. 08/31/1366 STEM CELLS -PROF PRATIWI 2012
    • 67.  Transgenic animals have been used to produce pharmaceutical protein: example a human gene called AT III has been transferred to goats.  Goats milk contain this protein that prevents blood clotting (goats multiply faster than cows)  “Hen bioreactor” eggs are used to enrich protein by recombinant DNA technology. 08/31/1367 STEM CELLS -PROF PRATIWI 2012
    • 68. Transgenic Goats That Produce Valuable Proteins in Their Milk – “Biorectors” 08/31/1368 STEM CELLS -PROF PRATIWI 2012
    • 69. A Summary of Animal Cloning  Although there has been limited success in cloning some animals, it's still seen as a viable technology.  Ever since the announcement of the birth of Dolly, additional sheep, cows, goats, pigs, and mice have been cloned. 08/31/1369 STEM CELLS -PROF PRATIWI 2012
    • 70. :  There are still obvious problems as evidenced from the numerous deaths of cloned animals that occur just before or after birth.  Cloning is a big first step. Genetic manipulation of cloned animals is the future direction of the cloning frontier. 08/31/1370 STEM CELLS -PROF PRATIWI 2012
    • 71. 08/31/1371 STEM CELLS -PROF PRATIWI 2012
    • 72. 08/31/13STEM CELLS -PROF PRATIWI 201272

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