Lactobacillus fermentum KLB12의 열 스트레스 내성 증진에 대한 연구

초록

Lactobacilli have been considered to play important roles in the health of human vagina. They secrete inhibitory substances to prevent vaginal infection by pathogenic organisms. In a previous study, we have isolated several lactobacilli from Korean woman and one of them (KLB12) was selected for further study and indentified as Lactobacillus fermentum by sequence analysis of 16S rRNA gene. In this study, we found that heat stress at 60℃ for 20∼30 min reduced the viable cell population of KLB12 by 106∼109. However, adaptation of KLB12 cells at 52℃ made them more thermotolerant upon exposure to 60℃. For pharmaceutical formulation, the spray-drying process is required where stress such as high temperature is routinely applied. Formulated L. fermentum KLB12 can be used for ecological treatment of bacterial vaginosis. The level of thermal protection in RSM (reconstituted skim milk) by adaptation in acid (pH 5), cold (4℃), ethanol (3%), NaCl (0.3 M) was also examined. Although not as efficient as the homologous stress, adaptations in both cold and NaCl gave considerable cross protection against heat stress. When chloramphenicol was added during heat adaptation, adaptation effect was abolished. This confirms that de novo protein synthesis is necessary during the adaptation process. Important changes in proteome during heat adaptation will be examined with two-dimensional gel electrophoresis.