Golden rice

2. Golden rice Vitamin A deficiency can result in night blindness and weakened immunity. It affects over 250 million people each year. I can’t see in dim light.

3. Golden rice Our body can synthesize vitamin A from beta-carotene.

4. Golden rice Scientists have successfully transferred the genes for producing beta-carotene from maize and bacteria to rice plants. genes

5. Golden rice The resultant Golden Rice can produce high levels of beta-carotene in its grains.

6. A Swiss scientist developed transgenic golden rice rich in iron and vitamin A, two major nutrient deficiencies in developing countries where the major staple food is rice. This involved genetically engineering 3 proteins and the vitamin precursor β-carotene from 4 different species.

7. 1 What are the advantages of genetic engineering over traditional breeding in crop improvement

8. 2.1 Biotechnology in medicine Production of pharmaceutical products • human insulin similar processes • human growth hormone • vaccines • monoclonal antibodies (單克隆抗體)

9. 2.1 Biotechnology in medicine 1 Human growth hormone (HGH) • secreted from the pituitary gland • important in development of bones and muscles • deficiency:

10. 2.1 Biotechnology in medicine 1 Human growth hormone (HGH) • HGH was extracted from the pituitary gland of dead people  limited supply  contaminated with pathogens

11. 2.1 Biotechnology in medicine 1 Human growth hormone (HGH) • recombinant HGH  unlimited amount  pure  low cost

12. 2.1 Biotechnology in medicine 1 Human growth hormone (HGH) • bacteria are commonly used - provide plasmids that act as vectors - serve as host cells - can be transformed easily - can grow rapidly - can grow in inexpensive culture media - relatively stable culture

13. 2.1 Biotechnology in medicine 2 Vaccines • antigenic proteins can be produced by recombinant DNA technology e.g. vaccines against hepatitis B

14. 2.1 Biotechnology in medicine 2 Vaccines  Prepare a recombinant plasmid gene for viral surface protein plasmid

15. 2.1 Biotechnology in medicine 2 Vaccines  Introduce the recombinant plasmid into a yeast cell yeast cell

16. 2.1 Biotechnology in medicine 2 Vaccines  Culture GM yeast on a large scale

17. 2.1 Biotechnology in medicine 2 Vaccines  According to the genetic information of the viral gene, the GM yeast produces the viral surface protein

18. 2.1 Biotechnology in medicine 2 Vaccines  The viral surface protein is collected and purified for use

19. 2.1 Biotechnology in medicine 2 Vaccines • traditional hepatitis B vaccines contain the whole viruses  viruses may become active and infectious • recombinant hepatitis B vaccines contain only a viral surface protein  safer to use

20. Principle of Edible vaccine

21. 2.1 Biotechnology in medicine 3 Monoclonal antibodies • antibodies produced by the cell clones derived from a single parent B cell • highly specific

22. "magic bullet"monoclonal antibody • myeloma cells – keeing dividing--immortal • fuse with healthy antibody-producing B-cells • Hybridomas produced • select hybridomas cells with specific antibodies • Grow in culture • Harvest monoclonal antibodies

23. 2.1 Biotechnology in medicine 3 Monoclonal antibodies i) For diagnosis of diseases • recognize the surface proteins of cancer cells in tissue samples

24. 2.1 Biotechnology in medicine 3 Monoclonal antibodies ii) For developing sensitive tests • home pregnancy tests • bind to human chorionic gonadotrophin (HCG) in urine

25. Application of monoclonal antibodies:Pregnancy testing kit

26. 2.1 Biotechnology in medicine 3 Monoclonal antibodies iii) For isolating and purifying important biological molecules • specific to the molecule of interest

27. 2.1 Biotechnology in medicine 3 Monoclonal antibodies • Drawback of monoclonal antibodies produced using B cells from mice  could stimulate an immune response in humans Results in their rapid removal from the blood, inflammatory effects, and the production of human anti-mouse antibodies

28. 2.1 Biotechnology in medicine In vitro / Recombinant Monoclonal antibodies: Made by merging mouse DNA encoding the binding portion of a monoclonal antibody with human antibody-producing DNA in living cells, and the expression of this hybrid DNA through cell culture yielded partially mouse, partially human monoclonal antibody. a human antibody with a small part of a mouse monoclonal antibody  less likely to be destroyed in the human body

29. 2.1 Biotechnology in medicine 3 Monoclonal antibodies • recombinant monoclonal antibodies • used in the treatment of some forms of cancer - linked with a toxic drug or a radioactive substance –magic bullet

30. 2.1 Biotechnology in medicine Gene therapy • to treat a disease by supplementing the defective gene with a normal gene • vectors for transferring a normal gene into a target cell e.g. harmless viruses

31. Diagram of the human chromosome set, showing the location of some genes whose mutant forms can cause hereditary diseases. Conditions that can be diagnosed using DNA analysis are indicated by a red dot. 

32. 2.1 Biotechnology in medicine Gene therapy • ex vivo(先體外後體內) gene therapy: cells are genetically modified outside the body and then put back into the patient

33. Gene therapy with a retrovirus

34. 2.1 Biotechnology in medicine Gene therapy • in vivo(體內) gene therapy: cells are genetically modified inside the body vectors with normal genes direct transfer of normal genes into cells

36. Cystic fibrosis (CF), the most common lethal, single-gene disorder affecting Northern Europeans and North Americans, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

37. 2.1 Biotechnology in medicine Gene therapy • germlinegenetherapy(種系基因治療) : corrects the genetic material of gametes or zygotes • genetic correction is inheritable • done on animals only

38. 2.1 Biotechnology in medicine Gene therapy • somatic cell gene therapy (體細胞基因治療) : corrects the genetic material of somatic cells • genetic correction is not inheritable • all human trials are of this type

39. 2.1 Biotechnology in medicine Gene therapy Potential benefits • treat genetic diseases, cancer and infectious diseases • as a preventive measure against diseases • correct a disease before it develops and help remove all the defective genes in the human population

40. 2.1 Biotechnology in medicine Gene therapy Potential hazards • viral vectors cause diseases • viral vectors cause severe immune reactions • insertion of new genes affects the expression of existing genes

41. 2.1 Biotechnology in medicine Gene therapy Potential hazards • new genes wrongly transported into non-target cells, produce too much of the missing protein or produce the protein at the wrong time

42. Risks involved in gene therapy • in an attempt experiment to treat Ornithine transcarbamylase deficiency by gene therapy, a patient died in 1999. • The patient was injected with adenovirusescarrying a corrected gene in the hope that it would manufacture the needed enzyme. • He died four days later, apparently having suffered a massive immune response triggered by the use of the viral vector used to transport the gene into his cells.

43. Risks involved in gene therapy • in an attempt experiment to treat Ornithine transcarbamylase deficiency by gene therapy, a patient died in 1999. • The patient was injected with adenovirusescarrying a corrected gene in the hope that it would manufacture the needed enzyme. • He died four days later, apparently having suffered a massive immune response triggered by the use of the viral vector used to transport the gene into his cells.

44. . Gene therapy poses many ethical and social questions • tampering with human genes mightlead to the practice of eugenics, a deliberate effort to control the genetic makeup of human populations. • The most difficult ethical question is whether we should treat human germ-line cells to correct the defect in future generations. • we will have to face the question of whether it is advisable, under any circumstances, to alter the genomes of human germ lines or embryos. Should we interfere with humanevolutionin this way?

45. 2.1 Biotechnology in medicine Stem cell therapy • unspecializedcells • unlimited mitotic cell division • can differentiate into different kinds of cells • Embryonic stem cells /Adult stem cells • Differs in their “potency”

46. totipotent, pluripotent, multipotent?

47. totipotent, pluripotent, multipotent? • Totipotentcells can form all the cell types in a body, plus the extraembryonic, or placental, cells. Embryonic cells within the first couple of cell divisions (8-cell stage) after fertilization are the only cells that are totipotent. • Pluripotentcells can give rise to all of the cell types that make up the body. e.g. embryonic stem cells (16-cell stage). • Multipotentcells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells, peripheral blood stem cells are considered multipotent.

48. 2.1 Biotechnology in medicine Stem cell therapy • embryonic stem cells • from blastocysts • can differentiate into almost any cell types • (Pluripotent)

49. After fertilization, the zygote undergoes cleavage:the first few mitotic divisions multiply the total number of cells without increasing total mass.The ball of cells that implants in the uterus is a blastocyst, and contains the inner cell mass, where embryonic stem cells can be harvested.

50. 2.1 Biotechnology in medicine Stem cell therapy • adult stem cells • from childhood or adult tissues like bone marrow, blood, skeletal muscles • can only differentiate into a limited range of cell types “Multipotent” or unipotent