Decoding contact-dependent communication and coordination in bacteria

解码细菌中依赖接触的通讯和协调

• 批准号: RGPIN-2016-06637
• 负责人: Islam, Salim
• 金额: $ 2.26万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654335
• 关键词: Decoding; contact; dependent; communication; coordination

The long-held notion of bacteria as “bags of enzymes” has undergone a paradigm shift in the past several years, with many eukaryotic traits now also identified in bacteria. One such trait is multicellularity (through differentiated cell fates), as exemplified by the Gram-negative social bacterium Myxococcus xanthus; upon starvation, swarms induce formation of spore-filled fruiting bodies by certain cells, exploration of the local environment by others, and programmed cell death by yet a third subpopulation to provide nutrients for cannibalistic feeding, all without conventional quorum sensing systems. Individual M. xanthus cells moving on hard surfaces leave behind slime polysaccharide trails, which can be followed by subsequent cells and swarms. Slime trails also contain outer-membrane vesicles/tubes left behind by previously-transited cells. However, the role of cell-surface factors in the discrimination of material from “self” vs. “non-self” sources has also never been characterized. As such, numerous questions remain as to how bacteria can communicate and coordinate their actions across an entire population simply through contact with self-generated signals and each other to effect multicellular behaviour.***This research program aims to determine the mechanisms and roles of bacterial surface dynamics in the coordination of bacterial population behaviour. Specifically, we will examine the basis by which subsequent “chase” cells preferentially follow previously-deposited slime trails from “seed” cells, and whether or not the uptake of outer-membrane debris from kin cells in these trails affects this outcome. Complementarily, we will elucidate the process by which slime is produced as well as the chemical properties of the polysaccharide that contribute to its adhesiveness. As outer-membrane debris is prevalent in slime trails, we will also characterize the events responsible for this dynamic deposition of surface material, including the structural factors of the membrane itself that may predispose it to such phenomena. Finally, we will identify the surface-associated bacterial factors responsible for distinguishing kin cells from those that are not related. We will address these questions through the use of multidisciplinary and cutting-edge microfluidics, click chemistry, structural biology, and high-throughput screening techniques, yielding unprecedented insights into the mechanisms and roles of outer-membrane dynamics in bacteria. The long-term vision for this research program is to develop a comprehensive understanding of the interplay between bacterial components that are crucial for contact-mediated communication and fundamental behavioral coordination; this will revolutionize our understanding of bacterial survival and persistence in niches as diverse as soils and rivers, to the gastrointestinal tract and its associated microbiota.**

细菌作为“酶袋”的长期概念在过去几年中经历了范式转变，现在在细菌中也发现了许多真核生物的特征。 一个这样的特性是多细胞性（通过分化的细胞命运），如革兰氏阴性社会细菌黄色粘球菌（Myxococcus xanthus）;在饥饿时，群体诱导某些细胞形成充满孢子的子实体，其他细胞探索当地环境，第三个亚群的程序性细胞死亡为同类相食提供营养，所有这些都没有传统的群体感应系统。 个体M.在坚硬表面上移动的黄藻细胞会留下粘液多糖的痕迹，随后的细胞和群会跟随这些痕迹。 粘液痕迹还包含由先前转移的细胞留下的外膜囊泡/管。然而，细胞表面因子在区分“自我”与“非自我”来源的材料中的作用也从未被描述过。 因此，许多问题仍然存在，即细菌如何通过自我产生的信号和相互接触来影响多细胞行为，从而在整个种群中沟通和协调它们的行动。该研究计划旨在确定细菌表面动力学在细菌群体行为协调中的机制和作用。 具体来说，我们将研究的基础上，随后的“追逐”细胞优先遵循先前沉积的粘液痕迹从“种子”细胞，以及是否从这些痕迹中的亲属细胞的外膜碎片的吸收影响这一结果。 作为补充，我们将阐明粘液产生的过程以及有助于其分解的多糖的化学性质。 由于外膜碎片是普遍存在于粘液痕迹，我们还将表征事件负责这种动态沉积的表面材料，包括膜本身的结构因素，可能使其易受这种现象。最后，我们将确定负责区分亲属细胞与无关细胞的表面相关细菌因子。 我们将通过使用多学科和尖端的微流体，点击化学，结构生物学和高通量筛选技术来解决这些问题，从而对细菌外膜动力学的机制和作用产生前所未有的见解。 这项研究计划的长期愿景是全面了解细菌成分之间的相互作用，这些成分对接触介导的通信和基本行为协调至关重要;这将彻底改变我们对细菌生存和持久性的理解土壤和河流等不同的利基，胃肠道及其相关的微生物群。