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Methods of gene transformation ~particle bombardment~ 簡維瑩 南師 自碩一 Introduction  Biodiversity Sexual reproduction  Reproductively isolated v.s gene transfer  Bacterium, plants, animals, …etc, have the same 遺傳物質—DNA & Methods of gene transformation  Foreign genes into the living cell  Biological methods  Agrobacterium,  Physical  Particle … methods bombardment  Protoplasts  Electroporation  Silicon carbide whiskers  Microinjection , ….etc. Methods of gene transformation Silicon carbide whiskers Methods of gene transformation micro_pulser electroporator Methods of gene transformation Microinjection Particle bombardment  Sanford, J.C. and co-workers (1987) Particle bombardment  Experiment  Small Ⅰ tungsten particles(average diameter 4µm)  Initial velocity of Particle leaving is about 430 m/s  Tissue : intact epidermal cells of Allium cepa (onion) Particle bombardment  Result: of the cells in a 1 cm2 of A. cepa epidermal tissue typically contain microprojectiles following bombardment.  90% Particle bombardment Relationship betwwen cell survival and the number of microprojectiles within a cell. Particle bombardment  Experiment Ⅱ  TMV(isolated from tobacco mosaic virus)  Small tungsten particles(average diameter 4µm)  A. cepa cells  Examine the bombarded cells microscopically for the presence of viral inclusion bodies(crystallized virus particles) 3 days after treatment Particle bombardment  ResultⅠ:  In the cytoplasm and vacuole of 30~40% of the cells that contained microprojectiles.  Be comparable to electroporation …etc. Particle bombardment  Experiment  Tungsten Ⅲ microprojectiles were coated with plasmid gene----p35S-CAT  A. cepa epidermal tissue  CAT assay Particle bombardment  ResultⅡ: Particle bombardment  To sum up…  Microprojectiles pierce cell walls and membranes and enter intact plant cells without killing them.  Microprojectiles were used to carry RNA or DNA into epidermal tissue of onion and these molecules were subsequently expressed genetically.  It would provide a broadly applicable transformation mechanism. Particle bombardment sourcegunpower , He , N2 …  Microprojectilestungstem or gold  Power  This process has been called  the microprojectile bombardment method,  the gene gun method, the particle  acceleration method,  biolistic process…etc. Particle gun designs Particle gun designs Particle gun designs