Effects of diadenylate cyclase deficiency on synthesis of extracellular polysaccharide matrix of Streptococcus mutans revisit.
Effects of diadenylate cyclase deficiency on synthesis of extracellular polysaccharide matrix of Streptococcus mutans revisit.
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DOI：
10.1111/1462-2920.13440
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发表时间：
2016-11
影响因子：
5.1
通讯作者：
X. Peng;S. Michalek;Hui Wu
中科院分区：
文献类型：
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作者：
X. Peng;S. Michalek;Hui Wu
一种新兴的第二信使c-di-AMP在细菌生理学中起着重要作用。Cheng等人报道，编码二腺苷酸环化酶（DAC）（一种产生c-di-AMP的酶）的基因的失活导致致龋细菌变形链球菌（Streptococcus mutans）的胞外多糖（EPS）合成增强（Cheng等人，2016年）。我们构建了一个类似的突变体，并观察到一个完全不同的效果，DAC缺陷导致EPS的生产减少。我们的研究提供了以下令人信服的证据：（1）我们构建的DAC突变体可以很容易地被补充以产生EPS，而来自Cheng组的突变体不能;（2）我们的突变体显示出产生EPS的关键酶-葡萄糖基转移酶（Gtfs）的规则模式，而Cheng等人报道的是不规则模式，这与他们早期的研究不一致。(3)我们证明了DAC突变体对氧化应激的反应不依赖于产生EPS的关键酶GtfB，而Cheng的报告表明，EPS的过量产生是DAC突变体适应氧化应激的反应机制。因此，Cheng等人报告的DAC和EPS之间关系的有效性需要进一步调查和澄清。
An emerging secondary messenger c-di-AMP plays an important role in bacterial physiology. It was reported by Cheng et al. that inactivation of a gene coding for diadenylate cyclase (DAC), a c-di-AMP producing enzyme, resulted in enhanced synthesis of extracellular polysaccharides (EPS) by a cariogenic bacterium, Streptococcus mutans (Cheng et al., 2016). We constructed a similar mutant and observed a completely different effect, the DAC deficiency resulted in a decrease in the production of EPS. Our studies provided the following compelling evidence, (1) the DAC mutant we constructed can be readily complemented for the production of EPS, while the mutant from the Cheng group cannot; (2) Our mutant exhibits the regular pattern of key enzymes that produce EPS, glucosyltransferases (Gtfs), while Cheng et al. reported an irregular pattern, which was inconsistent with their earlier studies. (3) We demonstrated that the response of the DAC mutant to oxidative stress is independent of GtfB, the key enzyme producing EPS, while the Cheng report suggests that overproduction of EPS is a responsive mechanism for the DAC mutant to adapt to the oxidative stress. Therefore, the validity of the relationship between DAC and EPS reported by Cheng et al. warrants further investigation and clarification.