Laboratory of Food Hygienic Chemistry, Department of Food Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
Laboratory of Food Hygienic Chemistry, Department of Food Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
Appl Environ Microbiol. 2020 Aug 3;86(16). doi: 10.1128/AEM.00935-20.
YafQ is an endoribonuclease toxin that degrades target gene transcripts such as that of , a gene encoding tryptophanase to synthesize indole from tryptophan. DinJ is the cognate antitoxin of YafQ, and the YafQ-DinJ system was reported to regulate persister formation by controlling indole production in In this study, we investigated the role of YafQ-DinJ, indole production, and persister population in bacterial heat tolerance. (Δ), (Δ), and (Δ) single-gene knockout mutants showed approximately 10-fold higher heat tolerance than wild-type (WT) BW25113. Persister fractions of all mutants were slightly larger than that of the WT. Interestingly, these persister cells showed an approximately 100-fold higher heat tolerance than normal cells, but there was no difference among the persister cells of all mutants and the WT in terms of heat tolerance. Indole and its derivatives promoted a drastic reduction of bacterial heat tolerance by just 10 min of pretreatment, which is not sufficient to affect persister formation before heat treatment. Surprisingly, indole and its derivatives also reduced the heat tolerance of persister cells. Among the tested derivatives, 5-iodoindole exhibited the strongest effect on both normal and persister cells. Our study demonstrated that a small persister population exhibits significantly higher heat tolerance than normal cells and that this small fraction contributes to the heat tolerance of the total bacterial population. This study also demonstrated that indole, known to inhibit persister formation, and its derivatives are very promising candidates to reduce the heat tolerance of not only normal bacterial cells but also persister cells.
YafQ 是一种内切核酸酶毒素，可降解靶基因转录本，如编码色氨酸酶的 基因，从而将色氨酸转化为吲哚。DinJ 是 YafQ 的同源解毒蛋白，据报道，YafQ-DinJ 系统通过控制吲哚的产生来调节持续存在体的形成。在本研究中，我们研究了 YafQ-DinJ、吲哚产生和持续存在体群体在细菌耐热性中的作用。 (Δ)、 (Δ)和 (Δ)单基因敲除突变体比野生型 (WT) BW25113 的耐热性高约 10 倍。所有突变体的持续存在体分数略大于 WT。有趣的是，这些持续存在体细胞的耐热性比正常细胞高约 100 倍，但在耐热性方面，所有突变体的持续存在体细胞与 WT 之间没有差异。吲哚及其衍生物仅预处理 10 分钟就大大降低了细菌的耐热性，这不足以影响热处理前的持续存在体形成。令人惊讶的是，吲哚及其衍生物也降低了持续存在体细胞的耐热性。在所测试的衍生物中，5-碘吲哚对正常细胞和持续存在体细胞都表现出最强的影响。我们的研究表明，一小部分持续存在体表现出比正常细胞更高的耐热性，并且这一小部分有助于总细菌群体的耐热性。本研究还表明，吲哚，已知抑制持续存在体形成，及其衍生物是非常有前途的候选物，不仅可以降低正常细菌细胞的耐热性，还可以降低持续存在体细胞的耐热性。
