Laboratory of Food Microbiology and Hygiene, Graduate School of Integrated Sciences for Life, Hiroshima Universitygrid.257022.0, Higashi-Hiroshima, Japan.
Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India.
Appl Environ Microbiol. 2022 Sep 13;88(17):e0104422. doi: 10.1128/aem.01044-22. Epub 2022 Aug 15.
We investigated the influence of sequence mutations on the biofilm formation of Vibrio cholerae. In this study, sequences from 85 V. cholerae strains belonging to both pandemic and nonpandemic serogroup were investigated through phylogenetic and sequence analyses. Biofilm formation assays under aerobic and anaerobic conditions were also performed. Sequence variations include single point mutations and insertions/deletions (indels) leading to either truncated or frameshifted HapR. Population structure analysis revealed two major haplogroups, and . Phylogenetic reconstruction displayed a hypothetical ancestral sequence located within the haplogroup. Higher numbers of single nucleotide polymorphisms and genetic diversity indices were observed in , while indels occurred dominantly in Aerobic conditions supported more robust biofilms compared to anaerobic conditions. Strains with frameshifted HapR produced the largest amount of biofilm under both oxygen conditions. Quantitative real-time PCR assay confirmed that strains with truncated and frameshifted HapR resulted in a nonfunctional regulator as exhibited by the significantly low gene expression. The present study shows that HapR mutations had a strong influence on biofilm formation and that sequence polymorphisms leading to the disruption of DNA-binding sites or dimerization of the HapR will result in more-robust V. cholerae biofilms. Our study revealed an ancestral sequence from a phylogenetic reconstruction that displayed the evolutionary lineage of the nonpandemic to the pandemic strains. Here, we established and as major haplogroups. The association of the O1 and O139 serogroups with the haplogroup demonstrated the distinction of in causing cholera infection. Moreover, mutations in this regulator that could lead to the disruption of transcription factor-binding sites or dimerization of the HapR can significantly affect the biofilm formation of V. cholerae. These observations on the relationship of the polymorphism and V. cholerae biofilm formation will provide additional considerations for future biofilm studies and insights into the epidemiology of the pathogen that could ultimately help in the surveillance and mitigation of future cholera disease outbreaks.
我们研究了序列突变对霍乱弧菌生物膜形成的影响。在这项研究中，通过系统发育和序列分析，对属于流行和非流行血清群的 85 株霍乱弧菌菌株的序列进行了研究。还进行了有氧和厌氧条件下生物膜形成的测定。序列变异包括单点突变和插入/缺失（indels），导致 HapR 截断或移码。群体结构分析显示存在两个主要的单倍型群，和。系统发育重建显示位于单倍型群内的假定祖先序列。在 中观察到更多的单核苷酸多态性和遗传多样性指数，而 indels 主要发生在 有氧条件下支持比厌氧条件下更健壮的生物膜。在两种氧气条件下，具有移码 HapR 的菌株产生的生物膜量最大。实时定量 PCR 检测证实，具有截断和移码 HapR 的菌株由于表现出非功能性调节剂，导致 基因表达显著降低。本研究表明，HapR 突变对生物膜形成有很强的影响，导致 DNA 结合位点破坏或 HapR 二聚化的序列多态性将导致更健壮的霍乱弧菌生物膜。我们的研究从系统发育重建中揭示了一个祖先序列，该序列显示了非流行株到流行株的进化谱系。在这里，我们确定 和 为主要的单倍型群。O1 和 O139 血清群与 单倍型群的关联表明了 在引起霍乱感染方面的区别。此外，该调节剂的突变可能导致转录因子结合位点的破坏或 HapR 的二聚化，这可能显著影响霍乱弧菌生物膜的形成。这些关于 多态性与霍乱弧菌生物膜形成之间关系的观察结果，将为未来的生物膜研究提供额外的考虑因素，并深入了解病原体的流行病学，最终有助于监测和减轻未来的霍乱疾病爆发。
