• YAKHAK HOEJI
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• v.40 no.1
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• pp.59-64
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• 1996

Gram-positive bacteria, Bacillus subtilis BR151 and Staphylococcus aureus RN4220 were transformed with high efficiency by electroporation. The cells were incubated until late log phase, washed three times with 10% glycerol, 1mM HEPES, 12% sucrose and resuspended to $10^{10}{\sim}10^{11}cfu/ml$, then stored at -$70^{\circ}C$. Transformation efficiency of B. subtilis BR151 was $1.03{\times}10^7cfu/{\mu}g$ with cells washed with 10% glycerol and electroporated by 15KV/cm, 0.7msec pulse with pUB110. Transformation efficiency of S. aureus RN4220 was $4{\times}10^6cfu/{\mu}g$ with cells washed with 1mM HEPES + 10% glycerol and electroporated by 15KV/cm, 2.5msec pulse. The number of total transformants was 1000 when B. subtilis BRI51 was transformed with 100ng pUB110 DNA and the number of total transformants was 9000 when S. aureus RN4220 was transformed with 10ng pUB110 DNA

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.345-348
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• 1985

Recombinant chimeric plasmid constructed with Xba I digested pUBl10 and -pE194 was transformed by polyethylene glycol induced protoplast transformation system into Bacillus subtilis BR 151 on the mannitol regeneration media, and two genes of antibiotics resistance were expressed simultaneously in the transfromant. Transformation frequency of the recombinant plasmid was 6.5 $\times$ 10$^{-5}$ on the mannitol regeneration agar plate containing neomycin and erythromycin. The replication of recombinant plasmid in the recipient cells was confirmed by the alkaline extraction method and agarose gel electrophoresis.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.297-302
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• 1985

The 7.1 Mdal Xbaf fragment of Bacillus pasteurii ATCC 11859 containing gene for urease was inserted into the Xbal site of bifunctional plasmid pGR71, and its urease gene was cloned and expressed in E. coil RRI. But the cloned gene was not expressed in Bacillus subtilis BR151 in consequence of deletion of inserted DNA fragment. The recombinant plasmid thus formed was named pGU66. The restriction map of the plasmid pGU66 was determined, and the size of the plasmid was estimated to be 12.6 Mdal by double digestion of restriction enzymes of the plasmid. The urease of the cloned strain was accumulated in periplasmic space and very similiar to that of donor strains in their enzymatic properties.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.293-299
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• 1994

Forty nine clinical isolates of S. aureus showing resistance to erythromycin(EM) were selected from 83 strains isolated recently in Korea. Fourteen strains of S. aureus showing inducible resistance to MLS antibiotics were selected by disc agar diffusion method. Colony hydridization was executed using two MLS inducible resistance genes, ermA and ermC, identified previously from S. aureus as probes. S. aureus 375 and S. aureus 507 whose genes were not homologous to those probes were finally selected. It was confirmed that the resistance genes of S. aureus 375 and S. aureus 507 had no homology with those probes in southern hybridization test using ermA, ermC and ermAM as probes. It was determined that S. aureus 375 had a plasmid whose size was about 35 kb. To know if the plasmid may have the genes related to inducible resistance to MLS antibiotics, it was attempted to transform Bacillus subtillis BR151 and S. aureus RN4220 with the plasmid isolated from S. aureus 375. It was shown that the gene related to inducible resistance to MLS antibiotics did not exist in this plasmid. These results indicate that two clinical isolates of S. aureus showing inducible resistance to MLS antibiotics have novel genes that have no homology with MLS resistance genes identified so far. It is assumed that these genes may exist in chromosomal DNA.