Bacteriocins and survival in the biofilm environment

细菌素和生物膜环境中的存活

• 批准号: RGPIN-2019-06454
• 负责人: Levesque, Celine
• 金额: $ 2.62万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738920
• 关键词: Bacteriocins; survival; biofilm; environment

Biofilms represent the predominant form of bacterial life. When presented with a surface or an interface and conditions advantageous for growth, bacteria almost always will assemble as a group of cells encapsulated within a self-produced protective extracellular matrix. Biofilms allow survival of bacteria in hostile environments, such as UV exposure, dehydration, salinity, and several disinfectants and biocidal agents. When bacteria are growing within biofilms, they secrete signaling molecules that increase in concentration as a function of cell density. In a process called quorum sensing, bacteria communicate with one another by using signaling molecules to regulate their gene expression in response to fluctuations in the cell population density. A wide array of phenotypes is controlled by quorum sensing including biofilm formation, bacteriocin production, and genetic competence for acquisition of exogenous DNA. Thus, quorum sensing allows bacteria to display a unified response that benefits the bacteria during adaptation to environment, colonization, and defense against competitors. Bacteriocins are ribosomally synthesized proteinaceous antibacterial peptides. They selectively interfere with the growth of other bacteria, and regulation of bacteriocin production plays an important role in the competitive interactions in bacterial biofilms. Extensive work done by my group showed that quorum sensing can also function as a stress-inducible system by triggering the signaling to the bacterial population to initiate an adaptive response that results in different outcomes. Biofilms are very complex and a fundamental property of bacteria is their ability to regulate cell growth when faced with a fluctuating environment. The production and secretion of bacteriocins in response to environmental stressors could confer a distinct ecological advantage to the producer in competing against other bacteria that are present in the same ecological niche or as a possible mechanism for the acquisition of DNA from other species during the genetic competence state. Using Streptococcus mutans as a model - chosen because of its relevance of a biofilm lifestyle, my overall goal is to answer the following question: Do microbial growth modulators such as bacteriocins play a role in competition, biodiversity and ecological fitness of the biofilm? Research (past and ongoing) from my lab suggests a complex interplay between quorum sensing (signal), bacteriocin activation (response), and biofilm persistence (phenotype) as a reaction to the environmental perturbations. Using state-of-the-art technology to elucidate the physiology and gene activities of biofilms, my research has the potential to contribute to the development of cost-effective biocidal strategies for the control and/or eradication of microbial biofilms.

生物膜代表细菌生命的主要形式。当存在有利于生长的表面或界面和条件时，细菌几乎总是组装成一组封装在自我产生的保护性细胞外基质内的细胞。生物膜允许细菌在恶劣的环境中存活，例如UV暴露、脱水、盐度和几种消毒剂和生物杀灭剂。当细菌在生物膜内生长时，它们分泌的信号分子浓度随着细胞密度的增加而增加。在一个被称为群体感应的过程中，细菌通过使用信号分子来调节它们的基因表达以响应细胞群体密度的波动来相互交流。群体感应控制着生物膜的形成、细菌素的产生和获取外源DNA的遗传能力。因此，群体感应允许细菌在适应环境、定殖和防御竞争对手期间显示有利于细菌的统一响应。细菌素是核糖体合成的蛋白质类抗菌肽。它们选择性地干扰其他细菌的生长，并且细菌素产生的调节在细菌生物膜中的竞争相互作用中起着重要作用。我的小组所做的大量工作表明，群体感应也可以作为一个应激诱导系统，通过触发细菌群体的信号来启动适应性反应，从而导致不同的结果。生物膜是非常复杂的，细菌的一个基本特性是它们在面对波动的环境时调节细胞生长的能力。细菌素的生产和分泌，以应对环境的压力，可以赋予一个独特的生态优势，生产者在竞争中对其他细菌，是存在于同一生态位或作为一种可能的机制，收购的DNA从其他物种在遗传能力状态。使用变形链球菌作为模型-选择它是因为它与生物膜生活方式的相关性，我的总体目标是回答以下问题：微生物生长调节剂如细菌素在生物膜的竞争，生物多样性和生态适应性中发挥作用？我实验室的研究（过去和正在进行的）表明，作为对环境扰动的反应，群体感应（信号），细菌素激活（反应）和生物膜持久性（表型）之间存在复杂的相互作用。使用最先进的技术来阐明生物膜的生理和基因活性，我的研究有可能有助于开发成本效益高的生物杀灭策略，以控制和/或根除微生物生物膜。