Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
Curr Microbiol. 2012 Dec;65(6):719-25. doi: 10.1007/s00284-012-0225-1. Epub 2012 Sep 11.
Genus Deinococcus is characterized by an increased resistance toward reactive oxygen species (ROS). The chromosome of five strains belonging to this genus has been sequenced and the presence of a luxS-like gene was deduced from their genome sequences. The aim of this study was to assess if a complete QS circuit is present in Deinococcus sp. and if this QS is associated with ROS. Primers for searching luxS-like gene and the putative receptor gene, namely ai2R, were designed. AI-2 signal production was evaluated by luminescence analysis using Vibrio harveyi BB170 as reporter strain. AI-2 signal was also evaluated by competitive assays using cinnamaldehyde, ascorbic acid, and 3-mercaptopropionic acid as interfering molecules. Potassium tellurite and metronidazole were used as oxidative stressors. A luxS-like gene as well as an ai2R gene was detected in strain UDEC-P1 by PCR. Cell-free supernatant of strain UDEC-P1 culture induced luminescence in V. harveyi BB170, and this property was inhibited with the three interfering molecules. The oxidative stressors metronidazole and potassium tellurite decreased Deinococcus sp. viability, but increased luminescence of the reporter strain. The results demonstrate that both a functional luxS-like gene and a putative receptor for AI-2 signal are present in Deinococcus sp. strain UDEC-P1. This finding also suggests that a complete QS circuit is present in this genus, which could be related to oxidative stress.
属的特征在于对活性氧（ROS）的抵抗力增加。该属的五个菌株的染色体已被测序，并从它们的基因组序列中推断出存在 luxS 样基因。本研究旨在评估 Deinococcus sp. 中是否存在完整的 QS 回路，以及这种 QS 是否与 ROS 相关。设计了用于搜索 luxS 样基因和假定受体基因 ai2R 的引物。使用 Vibrio harveyi BB170 作为报告菌株通过发光分析评估 AI-2 信号的产生。还使用肉桂醛、抗坏血酸和 3-巯基丙酸作为干扰分子通过竞争测定法评估 AI-2 信号。使用亚碲酸钾和甲硝唑作为氧化应激剂。通过 PCR 在菌株 UDEC-P1 中检测到 luxS 样基因和 ai2R 基因。菌株 UDEC-P1 培养物的无细胞上清液在 V. harveyi BB170 中诱导发光，并且该特性被三种干扰分子抑制。氧化应激剂甲硝唑和亚碲酸钾降低了 Deinococcus sp. 的活力，但增加了报告菌株的发光。结果表明，在 Deinococcus sp. 菌株 UDEC-P1 中存在功能齐全的 luxS 样基因和 AI-2 信号的假定受体。这一发现还表明，该属中存在完整的 QS 回路，这可能与氧化应激有关。
