研究人员发现捕食者与猎物的接触可以通过滑动运动或称之为“抓钩”的细胞外结构来建立。冷冻电子显微镜鉴定出抓钩是由IX型分泌系统底物形成的七聚体。
在捕食者与猎物建立紧密接触后，冷冻电子断层扫描和功能性检测显示，通过VI型分泌系统的穿刺介导了猎物的杀伤。
通过稳定同位素标记猎物的单细胞分析表明，捕食者吸收了猎物的成分。根据营养可用性，插入序列元件切换了粘附摄食的活性。一项海洋宏基因组时间序列研究显示了粘附摄食细菌与猎物之间的动态联系。
研究人员发现粘附摄食的机制涉及多种细胞机器，而且是保守的，并可能影响环境中的微生物种群。
据介绍，粘附摄食是丝状细菌在水生环境中依赖接触的捕食策略，其分子机制尚不清楚。
附：英文原文
Title: Mechanism of bacterial predation via ixotrophy
Author: Yun-Wei Lien, Davide Amendola, Kang Soo Lee, Nina Bartlau, Jingwei Xu, Go Furusawa, Martin F. Polz, Roman Stocker, Gregor L. Weiss, Martin Pilhofer
Issue&Volume: 2024-10-18
Abstract: Ixotrophy is a contact-dependent predatory strategy of filamentous bacteria in aquatic environments for which the molecular mechanism remains unknown. We show that predator-prey contact can be established by gliding motility or extracellular assemblages we call “grappling hooks.” Cryo–electron microscopy identified the grappling hooks as heptamers of a type IX secretion system substrate. After close predator-prey contact is established, cryo–electron tomography and functional assays showed that puncturing by a type VI secretion system mediated killing. Single-cell analyses with stable isotope–labeled prey revealed that prey components are taken up by the attacker. Depending on nutrient availability, insertion sequence elements toggle the activity of ixotrophy. A marine metagenomic time series shows coupled dynamics of ixotrophic bacteria and prey. We found that the mechanism of ixotrophy involves multiple cellular machineries, is conserved, and may shape microbial populations in the environment.
DOI: adp0614
Source: https://www.science.org/doi/10.1126/science.adp0614