Environmentally stress-inducible MazEF suicide module in the biofilm-forming organism streptococcus mutans

生物膜形成生物变形链球菌中环境应激诱导的 MazEF 自杀模块

• 批准号: 355968-2009
• 负责人: Levesque, Céline
• 金额: $ 1.82万
• 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: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=459670
• 关键词: Environmentally; stress; inducible; MazEF; suicide

Microbiologists have traditionally focused on free-floating bacteria growing in lab cultures; yet they have recently come to realize that in the natural world more than 99% of all bacteria live in biofilm communities. As a result, biofilms research is now one of the hottest topics in microbiology. Biofilms are ubiquitous and can developed on virtually every natural and man-made surface. The cost to society associated with biofilms (e.g. equipment damage, product contamination) is estimated to range in the billions of dollars annually. Biofilms represent a protected mode of growth that allow cells to survive a wide range of environmental challenges. A number of factors have been considered to be responsible for this renowned tenacity of biofilms. Recently, it has been proposed that a genetically determined process of bacterial suicide can occur as a feature of the dynamics of some bacterial populations that encounter stresses. Most bacterial chromosomes contain a number of suicide or toxin genes that induce cell growth arrest or death. This research proposal raises the hypothesis that bacteria tightly regulate the expression of their suicide systems to foster survival of their progeny in the biofilm. By regulating their suicide systems under various stresses, a subpopulation of cells in the community dies to permit the survival of the population as a whole (altruism). Streptococcus mutans will be used as model as this bacterium depends on a biofilm lifestyle for its survival in its natural ecosystem. The toxic activity of its toxin will be demonstrated using a protein expression system and the mechanism of action of the toxin characterized. The gene expression profiling of the suicide system after exposure to several environmental stressors will be determined. Finally, reporter systems will be constructed to study the transcriptional activities in in vivo biofilms. These results will provide knowledge of the mechanisms that determine microbial self-destruction for a better understanding of death events occurring in biofouling of any surfaces susceptible to microbial contamination. From an applied perspective, the results of this study may lead to the development of novel strategies to control and exploit the biofilm phenomenon in industry and environment technology.

微生物学家传统上关注在实验室培养物中生长的自由漂浮细菌;但他们最近意识到，在自然界中，超过99%的细菌生活在生物膜群落中。因此，生物膜研究现在成为微生物学中最热门的话题之一。生物膜无处不在，几乎可以在每一个自然和人造表面上形成。与生物膜相关的社会成本（例如设备损坏、产品污染）估计每年在数十亿美元的范围内。生物膜代表了一种受保护的生长模式，使细胞能够在广泛的环境挑战中生存。许多因素被认为是造成这种著名的生物膜韧性的原因。最近，有人提出，基因决定的细菌自杀过程可以作为某些细菌种群遇到压力时的动力学特征而发生。大多数细菌染色体含有大量自杀或毒素基因，这些基因可诱导细胞生长停滞或死亡。这项研究提出了一个假设，即细菌严格调节其自杀系统的表达，以促进其后代在生物膜中的生存。通过在各种压力下调节它们的自杀系统，群落中的细胞亚群死亡，以允许整个种群的生存（利他主义）。变形链球菌将用作模型，因为这种细菌依赖于生物膜生活方式在其自然生态系统中生存。其毒素的毒性活性将使用蛋白质表达系统和毒素的作用机制来证明。将确定暴露于几种环境应激物后自杀系统的基因表达谱。最后，构建报告基因系统，研究其在生物膜中的转录活性。这些结果将提供知识的机制，确定微生物的自我毁灭，更好地了解死亡事件中发生的任何表面易受微生物污染的生物污损。从应用的角度来看，本研究的结果可能会导致新的策略，以控制和利用生物膜现象在工业和环境技术的发展。