一个野生质粒赋予的抗生素多抗性的遗传分析与鉴定

一株分离自椰子果面的、在LA培养基上产紫色水不溶性色素的野生细菌对安苄青霉素、卡那霉素、潮霉素表现出强烈的抗性。质粒与总DNA的比较分析表明该野生细菌极可能携带一个具有抗生素多抗性的质粒。差异表达显示该质粒能够为抗生素强烈地诱导表达。该质粒的RFLP分析证明这株野生细菌多抗药性确实来自质粒，且该多抗质粒有7个EcoRI酶切位点和5个HindⅢ酶切位点。该质粒电转化大肠杆菌(E．coli)JM109获得9株对安苄青霉素、卡那霉素、潮霉素皆有抗性的转化子，并从转化子中抽提到该抗性质粒，这就更进一步证明该野生细菌对抗生素的多抗性确实来自同一个质粒。

GENETIC IDENTIFICATION AND ANALYSIS OF MULTI-RESISTANCE OF ANTIBIOTIC CONFERRED BY A PLASMID ISOLATED FROM FIELD BATERIA

A strain of bacterium isolated from coconuts, with wet and round phenotype in LA medium, producing purple pigment insoluble in water, shows strong antibiotic resistance to ampicillin, kanamycin and hygromycin. Comparative analysis of plasmid extraction and total DNA extraction testifies the bacterium harbors a putative plasmid with different resistant genes producing multi-resistance of antibiotic in its cytoplasm. Differential expression test proves the plasmid can be induced intensively. Analysis of restriction fragment length polymorphism (RFLP) of EcoR I and Hind III reveals the plasmid contains 7 and 5 restriction sites respectively hypothesizing it is a linear plasmid. Electroporation transformation of competent cell of the strain JM109 of E. coli which does not grow on the LA medium containing any antibiotic, mediated by the plasmid isolated from the bacterium, producing 9 transformants in which the plasmid can be recovered, growing on the selective medium with ampicillin,kanamycin and hygromycin furtherly shows that the multi-resistance of antibiotic is conferred by the plasmid.