Hafnia alvei H4 is a bacterium subject to regulation by a N-acyl-l-homoserine lactone (AHL)-mediated quorum sensing system and is closely related to the corruption of instant sea cucumber. Studying the effect of Hafnia alvei H4 quorum sensing regulatory genes on AHLs is necessary for the quality and preservation of instant sea cucumber. In this study, the draft genome of H. alvei H4, which comprises a single chromosome of 4,687,151 bp, was sequenced and analyzed and the types of AHLs were analyzed employing thin-layer chromatography (TLC) and high resolution triple quadrupole liquid chromatography/mass spectrometry (LC/MS). Then the wild-type strain of H. alvei H4 and the luxI/R double mutant (ΔluxIR) were compared by transcriptome sequencing (RNA-seq). The results indicate that the incomplete genome sequence revealed the presence of one quorum-sensing (QS) gene set, designated as lasI/expR. Three major AHLs, N-hexanoyl-l-homoserine lactone (C6-HSL), N-butyryl-l-homoserine lactone (C4-HSL), and N-(3-oxo-octanoyl)-l-homoserine lactone (3-oxo-C8-HSL) were found, with C6-HSL being the most abundant. C6-HSL was not detected in the culture of the luxI mutant (ΔluxI) and higher levels of C4-HSL was found in the culture of the luxR mutant (ΔluxR), which suggested that the luxR gene may have a positive effect on C4-HSL production. It was also found that AHL and QS genes are closely related in the absence of luxIR double deletion. The results of this study can further elucidate at the genetic level that luxI and luxR genes are involved in the regulation of AHL.

中文翻译：

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luxI / R基因对Hafnia alvei H4中AHL信号分子和QS调控机制的影响。

Hafnia alvei H4是受N-酰基-1-高丝氨酸内酯（AHL）介导的群体感应系统调节的细菌，与速溶海参的腐败密切相关。研究Hafnia alvei H4群体感应调控基因对AHL的影响对于即食海参的质量和保存是必要的。在这项研究中，基因组草案H.蜂房H4，其包括4687151碱基对的单染色体，进行测序和分析，并分析采用薄层色谱法（TLC）和高分辨率三重四极杆液相色谱/质谱类型信号分子的光谱法（LC / MS）。然后是H. alvei H4的野生型菌株和luxI / R双突变体（Δ通过转录组测序（RNA-seq）比较luxIR）。结果表明，不完整的基因组序列表明存在一种群体感应（QS）基因集，称为lasI / expR。三种主要的AHL，N-己酰基-1-高丝氨酸内酯（C6-HSL），N-丁酰基-1-高丝氨酸内酯（C4-HSL）和N-（3-氧代辛酰基）-1-高丝氨酸内酯（3- oxo-C8-HSL），其中C6-HSL最丰富。在luxI突变体（ΔluxR）的培养物中未检测到C6-HSL ，在luxR突变体（ΔluxR），这表明luxR基因可能对C4-HSL产生有积极作用。还发现在不存在luxIR双缺失的情况下，AHL和QS基因密切相关。这项研究的结果可以在遗传水平上进一步阐明luxI和luxR基因参与AHL的调节。