Oxygen dependent pyruvate oxidase expression and production in Streptococcus sanguinis.
Oxygen dependent pyruvate oxidase expression and production in Streptococcus sanguinis.
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DOI：
10.4248/ijos11030
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发表时间：
2011-04
影响因子：
14.9
通讯作者：
Kreth J
中科院分区：
文献类型：
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作者：
Zheng LY;Itzek A;Chen ZY;Kreth J
本研究的目的是表征血链球菌（S. sanguinis）中丙酮酸氧化酶（SpxB）基因表达和蛋白产生的氧依赖性调节。SpxB负责产生抑制生长的过氧化氢（H2O2），能够拮抗致龋齿变形链球菌（S. mutans）。此外，还研究了产H2O2对产菌株的自抑制能力。采用实时荧光定量RT-PCR和荧光表达报告菌株检测spxB的表达。在SpxB的c -末端，用FLAG表位进行了蛋白丰度的研究。用拮抗平板法检测自我抑制作用。在厌氧条件下生长的细胞中，表达量和蛋白丰度下降。血链球菌对自身产生的H2O2具有抗性，而致龋齿的变形链球菌的生长受到抑制。结果表明，在最初的生物膜形成过程中，当氧可用性允许spxB的表达和产生时，血链球菌产生H2O2作为抗菌物质来抑制S. mutans等敏感生态位竞争物种。
The objective of this study was to characterize the oxygen dependent regulation of pyruvate oxidase (SpxB) gene expression and protein production in Streptococcus sanguinis (S. sanguinis). SpxB is responsible for the generation of growth-inhibiting amounts of hydrogen peroxide (H2O2) able to antagonize cariogenic Streptococcus mutans (S. mutans). Furthermore, the ecological consequence of H2O2 production was investigated in its self-inhibiting ability towards the producing strain. Expression of spxB was determined with quantitative Real-Time RT-PCR and a fluorescent expression reporter strain. Protein abundance was investigated with FLAG epitope engineered in frame on the C-terminal end of SpxB. Self inhibition was tested with an antagonism plate assay. The expression and protein abundance decreased in cells grown under anaerobic conditions. S. sanguinis was resistant against its own produced H2O2, while cariogenic S. mutans was inhibited in its growth. The results suggest that S. sanguinis produces H2O2 as antimicrobial substance to inhibit susceptible niche competing species like S. mutans during initial biofilm formation, when oxygen availability allows for spxB expression and Spx production.