title: Improvement of transformation and electroduction in avermectin high-producer, Streptomyces avermitilis.
abstract: Factors affecting the PEG-mediated transformation and electrotransformation of Streptomyces avermitilis protoplasts, an industrial avermectin high-producer, were evaluated. The maximum protoplast transformation efficiency under optimum conditions with PEG was 3 x 106 transformants per microg plasmid pIJ702 DNA. The efficiency of electrotransformation with the same plasmid the intact cells grown in medium with 0.5 mmol/L CaCl2, suspended in buffer with 0.5 mol/L sucrose +1 mmol/L MgCl2, and pulsed at an electric field strength of 10 kV/cm, 800 ohms, 25 microF, was of 2 x 10(3) transformants per microg DNA. When the cells were electroporated after mild lysozyme-treatment, the efficiency was up to 10(4) transformants per microg DNA. Electroporation of protoplasts and germlings had a lower efficiency (10(2) transformants per microg DNA). We report that electroporation under optimum conditions can be used for direct transfer of nonconjugative plasmid pIJ699 between two different Streptomyces species, S. avermitilis and S. lividans.
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200 032, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Gong
authors.forename: Weihong
authors.initials: W
authors.lastname: Jiang
authors.forename: Yunliu
authors.initials: Y
authors.lastname: Yang
authors.forename: Juishen
authors.initials: J
authors.lastname: Chiao
mesh_terms: D018274:Electroporation; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000378:metabolism*; D011523:Protoplasts / Q000378:metabolism; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism; D014169:Transformation, Bacterial
chemical_list: D007559:Ivermectin; C019264:avermectin