| Summary: | 碩士 === 東吳大學 === 微生物學系 === 91 === Abstract
In a previous work （Jiang, 1996）, the NTG mutagenesis and cell fusion techniques were used to improve the organic solvent tolerance of an cholesterol- transforming bacterium Mycobacterium sp. NRRL B-3683. Six strains M6、M6-12、M6-33、MB9-35、MB9-44 were obtained. The purpose of this research is to characterize these strains. Three conclusions were obtained :(1) All six strains showed increase in the tolerance to organic solvent DMF,especially mutant strains M6-33 and M6-35,but decrease in the minimum inhibition concentration of antibiotics There were no significant difference in the mycolic acid and fatty acid composition when bacterial cells were obtained from the stress environment., It seems that the various strains change there cell wall permeability, but the tolerance to organic solvent has no direct relationship with the mechanism of tolerance to antibiotics. (2) The MB9-15 and NB9-44 are derived strains obtained from cell fusion technique, and their morphological characteristics are similar to mycobacterial strains obtained from NTG-mutagenesis. Various physiological characterizations and molecular techniques were used to distinguish these two groups of derived strains, but there were no significant difference between mutant strains and cell-fusioned strains. (3) The taxonomic position of NRRL B-3683 used in the present study is closely related to M. neaurum by 16s rDNA sequcing、PRA assay and physiological characterization.
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