• 한국미생물·생명공학회지
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• 제18권3호
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• pp.215-220
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• 1990

L.casei YIT 9018균주에 N-methyl-N'-nitro-N-nitrosoguanidine을 처리하여 thermoinducible mutants를 분리하였고, 이 균주를 $42^{\circ}C$에서 30분 동안 열처리하여 prophage가 cured된 균주 L.casei HYM 1213과 L.casei HYM 4024를 분리하였다. Prophage cured strain L.case HYM 1213과 L.casei HYM 4024는 temperate phage $\phi$Fsw에 대해 지시균으로서 능력을 가지고 있었으며, 어떤 온도에서도 temperate phage $\phi$FSW가 검출되지 않았다. 이들의 생리적 특성을 모균주인 L.caseiYIT 9018과 비교한 결과 L.casei HYM 1213 균주는 균의 증식, pH변화, 산생성능력, 당 발효능력에서 모균주와 유사한 것으로 나타났으나, L.casei HYM 4024균주는 pH변화와 산생성능력이 모균주에 비해 미약한 것으로 나타났다. Plasmid DNA는 두 균주 모두 모균주와 동일한 size를 보여주여, prophage가 cured되었어도 plasmid DNA에는 손실을 가져오지 않았음을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.467-476
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• 1994

Lactobacillus casei HY 2782, prophage cured strain was characterized to be stable as much as L casei YIT 9018, parent strain. By southern hybridization, it was confirmed that the temperate phage was incorporated in chromosomal DNA of L. casei YIT 9018 as a prophage. It was also proved that the prophage was cured from chromosomal DNA of L casei HY 2782. The growth rate, lactic acid producing ability, carbohydrates fermentation, and enzymatic activity of L. casei HY 2782 were found to be similar to those of L. casei YIT 9018. When L casei HY 2782 was used as a host, the multiplicity of infection (M.O.I.) of the temperate phage for L. casei HY 2782 was 1.0~5.0. Restriction enzyme analysis of pLC90 plasmid from L. casei HY 2782 was shown that the size was an approximately 68.22 kb. The plasmid profiles, genomic DNA patterns, and cellular fatty acids composition of L. casei HY 2782 were similar to those of L casei YIT 9018. And the major fatty acids composition of these strains were C$_{14;0}$,C$_{16;1}$, C$_{16;0}$, C$_{18;1}$ and C$_{19;cyclo-}$ 10 sets of arbitrary primer in the PCR were screened to find differentiation against two strains of L. casei. Among them, b$_{5}-1/17-1 primer was produced an approximately 1.3 kb DNA band of only L casei YIT 9018. And b$_{5}-2/17-2 primer was produced an approximately 1.0 kb DNA band of only L casei HY 2782.

• 한국미생물·생명공학회지
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• 제19권2호
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• pp.147-152
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• 1991

In order to study effect of the phage ${\phi}$ FSV on the growth of lactic acid bacteria, Lactobacillus casei YIT 9018(wild type strain with prophage) or L. casei HYM 1213 (prophage cured strain) was infected with various concentrations of phage ${\phi}$ FSV (called Lac S21) or wild type virulent phage (called Lac J-1). When L. casei YIT 9018 was infected with Lac S21 under the concentration of $6.0{\times}10^6$ pfu/ml, the growth and lactic acid production of the strain were normal and the number of phages decreased. But L. casei HYM 1213 was susceptible to Lac S21. Regardless of the concentration of the phage infection, the number of phages increased rapidly into $10^9$ to $10^{10}$ pfu/ml at 2 day cultures and was maintained $10^7$ to $10^9$pfu/ml phage until 6 day cultures. The lactic acid production of L. casei HYM 1213 infected with Lac S21 was abnormal. Therefore, phage ${\phi}$ FSV had an evil effect on growth of L. casei HYM 1213, but not L. casei YIT 9018. On the other hand Lac J-1 caused abnormal fermentation to either L. casei YIT 9018 or L. casei HYM 1213.