Laboratory of Molecular Microbiology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
FEMS Microbiol Lett. 2009 Oct;299(1):110-9. doi: 10.1111/j.1574-6968.2009.01742.x. Epub 2009 Jul 31.
Hemolysin II (HlyII) is a pore-forming toxin of the opportunistic pathogen Bacillus cereus. Despite our understanding of the mechanism of HlyII cytotoxicity in vitro, many of its characteristics, including potential target cells, conditions of its action and expression, are not known. Here we report that the expression of hlyII in Bacillus subtilis renders the bacteria hemolytic and is able to kill the crustacean Daphnia magna. The hemolytic activity of hlyII-encoded B. subtilis strains in culture media is positively correlated with virulence in D. magna. Fluorescence microscopy reveals postinfection changes in the mitochondrial potential of intestinal tissue, suggesting that the formation of ionic pores leads to cell death. In the presence of the transcriptional regulator HlyIIR, HlyII expression decreases 200-fold, and B. subtilis expressing both hlyII and hlyIIR remains hemolytic, but not pathogenic to the crustacean.
溶血素 II（HlyII）是机会性病原体蜡样芽胞杆菌的一种形成孔的毒素。尽管我们了解了 HlyII 在体外的细胞毒性机制，但它的许多特性，包括潜在的靶细胞、作用和表达条件，尚不清楚。在这里，我们报告说，hlyII 在枯草芽孢杆菌中的表达使细菌具有溶血活性，并能够杀死甲壳类动物大型溞。在培养基中编码 hlyII 的枯草芽孢杆菌菌株的溶血活性与在大型溞中的毒力呈正相关。荧光显微镜显示感染后肠道组织中线粒体电势的变化，表明离子孔的形成导致细胞死亡。在转录调节因子 HlyIIR 的存在下，hlyII 的表达降低了 200 倍，并且表达 hlyII 和 hlyIIR 的枯草芽孢杆菌仍然具有溶血活性，但对甲壳类动物没有致病性。
