고추냉이 추출물에 노출된 Bacillus cereus MK-11의 생리 및 세포반응

Abstract

The purpose of this study was to investigate the physiological and cellular responses of Bacillus cereus MK- 11 exposed to wasabi extracts. Initially, MK-11 isolated from commercial ssam-jang was examined for morphological and physiological characteristics. The BIOLOG system and 16S rRNA sequencing analysis were performed to identify the strain. It was assigned and designated as B. cereus MK-11. The phylogenetic tree of B. cereus MK-11 was plotted based on 16S rRNA sequence comparisons. Wasabi extracts showed a dose-dependent antibacterial effect on B. cereus MK-11, while MK-11 treated using 2 mg/mL wasabi extracts completely inhibited growth within 24 h of incubation. The amount of alginate produced by the exposure of wasabi extracts decreased with increasing concentrations of the extracts, and increased with exposure time. The stress shock proteins (e.g., DnaK and GroEL), which may contribute to enhancing the cellular resistance to the cytotoxic effect of wasabi extracts, decreased in proportion to the concentrations of wasabi extracts used for this study. The SEM analysis showed the presence of major structural change in the envelope, as well as a preponderance of irregular rod forms with wrinkled surfaces in cells treated with sublethal concentrations of wasabi extracts. In conclusion, it will be a crucial clue to understanding the cytotoxic mechanisms of Bacillus cereus exposed to wasabi extracts.