Research group for Physiology and Applications of Microorganisms (PHAM group), GREENLAB, Center for Life Science Research (CELIFE), Faculty of Biology, University of Science - Vietnam National University in Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam.
Cell Therapy Department, Hi-Tech Center, Vinmec International General Hospital Joint Stock Company, Times City, 458 Minh Khai, Hai Ba Trung, Hanoi, Vietnam.
Sci Rep. 2022 Sep 8;12(1):15203. doi: 10.1038/s41598-022-19424-w.
Quorum sensing is the process by which microbial cells sense and respond to the co-presence of others in their surrounding, through the detection of their autoinducers associated with gene expression regulation and thereby controlling many physiological processes, such as biofilm formation and/or bioluminescence, etc. In Vibrio bacteria, where quorum sensing is relatively well understood with three commonly known autoinducers (HAI-1, AI-2 and CAI-1), both intra-species and inter-species cell-cell communications occur but no inter-Vibrio-species quorum sensing inhibition has been reported. In this study, by screening bacterial isolated from soil and mud samples in a northern province in Vietnam, we discovered a strain that reduced more than 75% of the bioluminescence of a Vibrio harveyi, with evidence showing that such an inhibition might be associated with quorum sensing inhibition. The strain, designated as XTS1.2.9, was identified to be a Vibrio parahaemolyticus bacterium based on its morphological, physiological, biochemical and phylogenetic characteristics. We also tested XTS1.2.9 for its bioluminescence inhibition against different mutants lacking different quorum sensing autoinducers by using plate assays. The results showed that XTS1.2.9 inhibited the bioluminescence of the mutants having sensor 1, especially the one detecting CAI-1, and lacking sensor for AI-2; while it did not inhibit the mutants having only sensor for AI-2 and lacking sensor 1. Therefore, we propose an intra-genus quorum sensing inhibition mechanism involving CAI-1 to explain for such interactions between Vibrio parahaemolyticus and Vibrio harveyi. This phenomenon is reported for the first time and may have certain scientific and application implications.
群体感应是微生物细胞通过检测与其基因表达调控相关的自动诱导物来感知和响应周围其他细胞共存的过程，从而控制许多生理过程，如生物膜形成和/或生物发光等。在弧菌中，群体感应相对较好理解，有三种常见的自动诱导物（HAI-1、AI-2 和 CAI-1），既有种内细胞间通讯，也有种间细胞间通讯，但没有报道过弧菌间的群体感应抑制。在这项研究中，我们通过筛选越南北部省份土壤和泥浆样本中分离出的细菌，发现了一种能够降低哈维弧菌生物发光超过 75%的菌株，有证据表明这种抑制可能与群体感应抑制有关。该菌株被命名为 XTS1.2.9，根据其形态、生理、生化和系统发育特征，被鉴定为副溶血弧菌。我们还通过平板试验测试了 XTS1.2.9 对不同缺乏不同群体感应自动诱导物突变体的生物发光抑制作用。结果表明，XTS1.2.9 抑制了具有传感器 1 的突变体的生物发光，特别是检测 CAI-1 的突变体，而缺乏 AI-2 的传感器；而对仅具有 AI-2 的传感器且缺乏传感器 1 的突变体则没有抑制作用。因此，我们提出了一种涉及 CAI-1 的属内群体感应抑制机制来解释副溶血弧菌和哈维弧菌之间的这种相互作用。这种现象是首次报道的，可能具有一定的科学和应用意义。
