Pecharki D, Petersen F C, Scheie A Aa
Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.
Oral Microbiol Immunol. 2008 Feb;23(1):79-83. doi: 10.1111/j.1399-302X.2007.00395.x.
BACKGROUND/AIMS: Autoinducer-2 (AI-2) is used by several bacteria in quorum-sensing signaling and is a product of LuxS. The aim was to investigate the effect of LuxS mutation on expression of Streptococcus intermedius virulence factors.
S. intermedius mutants were constructed by insertion inactivation or gene deletion. Real time RT-PCR was used to assess transcription of pas, ily and hyl. Hyaluronidase and intermedilysin activities were measured biochemically.
The results indicated that disruption of luxS in S. intermedius may affect hyaluronidase and intermedilysin gene expressions. No difference in antigen I/II expression was observed. Biochemical methods showed a five-fold decrease in hemolytic activity of the luxS mutant; however, secreted hyaluronidase activity was unaffected. The AI-2 precursor 4,5-dihydroxy-2,3-pentanedione complemented lack of AI-2 production by the mutant thus restoring hemolytic activity.
We suggest that AI-2 communication is involved in intermedilysin expression.
背景/目的：自诱导物-2（AI-2）被多种细菌用于群体感应信号传导，是LuxS的产物。目的是研究LuxS突变对中间链球菌毒力因子表达的影响。
通过插入失活或基因缺失构建中间链球菌突变体。采用实时逆转录聚合酶链反应（RT-PCR）评估pas、ily和hyl的转录情况。通过生化方法测定透明质酸酶和中间溶血素的活性。
结果表明，中间链球菌中luxS的破坏可能影响透明质酸酶和中间溶血素基因的表达。未观察到抗原I/II表达的差异。生化方法显示，luxS突变体的溶血活性降低了五倍；然而，分泌的透明质酸酶活性未受影响。AI-2前体4,5-二羟基-2,3-戊二酮补充了突变体缺乏的AI-2产生，从而恢复了溶血活性。
我们认为AI-2通讯参与了中间溶血素的表达。
