Analysis of Al-2/LuxS-dependent transcription in Campylobacter jejuni strain 81-176
Analysis of Al-2/LuxS-dependent transcription in Campylobacter jejuni strain 81-176
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DOI：
10.1089/fpd.2008.0106
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发表时间：
2008-08-01
影响因子：
2.8
通讯作者：
Chen, Chin-Yi
中科院分区：
文献类型：
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作者：
He, Yiping;Frye, Jonathan G.;Chen, Chin-Yi
自诱导物-2（A1 -2）是一种群体感应信号分子，在革兰氏阴性和革兰氏阳性细菌中控制响应细胞密度的多种细胞活性。Al-2的产生依赖于Al-2生物合成途径中的最后一个酶LuxS。在本研究中，我们在空肠弯曲菌菌株81-176中构建了一个luxS无效突变（Delta luxS），并显示它消除了Al-2的产生。与野生型（wt）相比，Delta luxS突变体在Mueller-Hinton（MH）肉汤中具有更长的倍增时间，并且在37 ℃下在MH软琼脂上减少了群集，而在42 ℃下的生长速率或群集不受影响。Delta luxS突变体在42 ℃下通过圆盘抑制测定对过氧化氢（H2 O2）和氢过氧化枯烯比野生型更敏感，但最小抑制浓度比较不确定。使用DNA微阵列比较了野生型和Delta luxS突变体在有和没有H2 O2处理的情况下全基因组基因表达的差异。表现出差异表达的基因（wt/Delta luxS）包括涉及AI-2合成和S-腺苷甲硫氨酸（SAM）代谢（metE、metF和pfs）、鞭毛组装/调节、应激反应（ahpC、tpx和groES）、ABC转运蛋白/外排系统的操纵子/途径，以及位于luxS下游的两个功能未知的基因（Cj 1199和Cj 1200）。ahpC（编码烷基氢过氧化物还原酶）和tpx（编码巯基过氧化物酶）的wt/Delta luxS表达比率仅在H2 O2处理下增加，这与我们的发现一致，即Delta luxS突变体比wt对氧化应激表现出更高的敏感性。我们的微阵列结果与Delta luxS突变体表型一致，并表明LuxS在SAM代谢的中心代谢中起作用，但Al-2是否作为C中真正的群体感应信号尚不确定。空肠。
Autoinducer-2 (Al-2) is a quorum-sensing signal molecule that controls a variety of cellular activities in response to cell density in both gram-negative and gram-positive bacteria. The production of Al-2 is dependent upon LuxS, the last enzyme in the Al-2 biosynthesis pathyway. For this study, we constructed a luxS null mutation (Delta luxS) in Campylobacter jejuni strain 81-176, and showe that it abolished Al-2 production. The Delta luxS mutant had a longer doubling time in Mueller-Hinton (MH) broth and reduced swarming on MH soft agar at 37 degrees C compared to the wild type (wt), whereas growth rate or swarming at 42 degrees C was not affected. The Delta luxS mutant was also more sensitive to hydrogen peroxide (H2O2) and cumene hydroperoxide than the wt by disc inhibition assays at 42 degrees C, though minimum inhibitory concentration comparisons were inconclusive. Differences in genome-wide gene expression between wt and Delta luxS mutant with and without H2O2 treatments were compared using DNA microarrays. The genes that showed differential expressions (wt/Delta luxS) include operons/pathways involved in AI-2 synthesis and S-adenosylmethionine (SAM) metabolism (metE, metF, and pfs), flagellar assembly/regulation, stress response (ahpC, tpx, and groES), ABC transporters/efflux systems, and two genes of unknown function located downstream of luxS (Cj1199 and Cj1200). The wt/Delta luxS expression ratios of ahpC (encoding alkyl hydroperoxide reductase) and tpx (encoding thiol peroxidase) were increased only with H2O2 treatment, consistent with our finding that the Delta luxS mutant exhibits higher sensitivity to oxidative stress than wt. Our microarray results agreed with the Delta luxS mutant phenotypes, and suggested that LuxS plays a role in central metabolism involving SAM metabolism, but it is uncertain whether Al-2 functions as a true quorum-sensing signal in C. jejuni.