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Genetically modified microbes
- 2. Introduction Recombinant DNAtechnology uses genetic engineering to introduce genes into microorganisms & other cells Then help produce metabolites of commercial or medical importance such as insulin,vitamin,aminoacids or enzymes. Most reason to prefer microbes because microorganisms grow rapidly & in most cases are easy to cultivate. Using microorganisms is much environmentally friendly than conventional chemical synthetic method; they use less energy & use renewable resources.
- 3. Today, geneticallymodified microorganisms (GMMs) have found applications in human health, agriculture, and bioremediation and in industries such as food, paper, and textiles. genetic engineering offers sufficient supplies of desired products, cheaper product production, and safe handling of otherwise dangerous agents.
- 4. Molecular tools forgenetic engineering of microorganisms To manipulate microorganisms for the expression of desired traits 1.Gene transfer method to deliver the selected genes into desired hosts. 2.Cloning vector 3.Promoters to control the expression of desired genes 4.Selectable marker genes to identify recombinant microorganisms
- 5. 1.Gene transfer method Transformation In this process uptake of plasmid DNA by recipient microorganisms is accomplished when they are in a physiological stage of competence. Electroporation Alternative method to transform DNA in to microorganisms. This method originally used to transform eukaryotic cells. High voltage pulses make recipient cells electrocompetant. Transient pores are formed in the cell membrane as a result of an electroshock, there by allowing DNA uptake
- 6. Conjugation This methodinvolves a donor strain that contains both the gene of interest & the origin of transfer (Ori T) on a plasmid & the gene encoding transfer function. The contact between donor & recipient DNA transform occurs. Vectors Cloning vectors to carry out genetic modifications depend upon choice of the gene transfer
- 7. Promoters Promoter isa segment of DNA that regulates the expression of the gene under its control 1.Constitutive promoters : continuously active 2.Inducible promoters : activate only certain condition – presence of inducer Selectable marker genes Which often encodes proteins conferring resistance to antibiotics for identifying transformants.
- 8. Strategies for geneticengineering of microorganisms 1. Disruption or complete removal of undesired genes or their pathways 2. Over expression of target gene high expression its an drawbacks, it leads to segregation of desirable genes & loss of desired traits. 3. Improving protein production properties.
- 9. Approaches to enhancingproduct yield Overcoming rate –limiting steps Eliminating feedback regulation Manipulating regulatory genes
- 10. Applications of GMMsderived products 1. Human health * Recombinant therapeutics proteins 1.Human insulin - Herbert Boyer 1978 -1st recombinant therapeutic protein approved by the FDA in 1982.was produced by genetically engineered E.coli containing human insulin genes 2.Human growth hormone (hGH) approved by FDA in 1985.was produced by modified E.coli strain containing native human growth hormone gene.
- 11. * Recombinant vaccines 1.Saccharomycescerevisiae common baker’s yeast produce Hepatitis B virus against vaccine based on the hepatitis B surface antigen. Trade name Engerix-B
- 12. Animal health 1.Recombinant vaccines toeradicate Rabies - antirabies ϒ globulin treatment Textile industry α-amylase of Bacillus stearothermophilus Amylases have been used for many years to remove starch sizes from fabrics, known as desizing. Originally, amylases from plant or animal sources were used. Later, they were replaced by amylases of bacterial origin.
- 13. Agriculture Nitrogen fixinggenes nif L & nif A can be inserted inti Rhizobium meliloti strain of bacteria ,there by increase the amount of nitrogen fixed by these bacteria Indigo a commercially blue pigment that is used to dye both cotton & & wool, was originally isolated from plants.-------- rec E.coli bacteria with plasmid NAH7 is used for producing indigo by biotechnological method.
- 14. Insecticidal Toxin genefrom Bacillus thuringensis israelensis is inserted into Synechocystis & Synecho coccus spp ( photosynthetic cyanobacteria that are food source of the mosquito larvae) Caucobacter crescentus an aquatic bacterium The insecticidal protein is highly toxic when ingested by mosquito larvae
- 15. Bioremediation Using microbesto clean up pollution Genetically engineered bacteria capable of cleaning oil spills. Oil contain four main group of Hydrocarbons present in oil (Xylenes,naphthalenes,octanes,camphor) The oil eating super bug was developed at Generic Electric in 1975 by Ananda mohan chakrabarty 1980 he received a patent on a genetically modified Pseudomonas putida bacterium that would eat up oil spills. He was the first person to win patent on a living organism
- 17. Pseudomonas putidacontain 1.OCT plasmid degrading octane, hexane & decane 2.XYL plasmid degrading xylene & toluene 3.CAM plasmid degrading camphor 4.NAH plasmid degrading naphthalene. Henry samueli ( school of engineering & applied science) produce genetically modified microorganism E.coli biofuel synthesizer
- 18. Food production Cheesemaking to produce chymosin Rhizomucormiebi Endothia parasitica Rhizopus pusillus Aspergillus niger , Kluyveromyces lactis,E.coli ----- rec chymosin developed in 1981 approved in 1988.90% of cheese prepared by these genetically modified bacteria.
- 19. Commonly used microbes Streptomyces Yeast Bacillus Corynebacterium E.coli Lactic acid bacteria Pseudomonas Aspergillus
- 20. Reference – Biotechnology microbiologyimmunology A T Thomas,P Cyril,Boby jose – Manjusha publication – Genetically Modified Microorganisms Development and Applications -Lei Han
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