Sydney Natashia, Swain Martin T, So Jeffery M T, Hoiczyk Egbert, Tucker Nicholas P, Whitworth David E
Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom.
Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.
Microb Physiol. 2021;31(2):57-66. doi: 10.1159/000515546. Epub 2021 Apr 1.
Bacterial predation is a ubiquitous and fundamental biological process, which influences the community composition of microbial ecosystems. Among the best characterised bacterial predators are the myxobacteria, which include the model organism Myxococcus xanthus. Predation by M. xanthus involves the secretion of antibiotic metabolites and hydrolytic enzymes, which results in the lysis of prey organisms and release of prey nutrients into the extracellular milieu. Due to the generalist nature of this predatory mechanism, M. xanthus has a broad prey range, being able to kill and consume Gram-negative/positive bacteria and fungi. Potential prey organisms have evolved a range of behaviours which protect themselves from attack by predators. In recent years, several investigations have studied the molecular responses of a broad variety of prey organisms to M. xanthus predation. It seems that the diverse mechanisms employed by prey belong to a much smaller number of general "predation resistance" strategies. In this mini-review, we present the current state of knowledge regarding M. xanthus predation, and how prey organisms resist predation. As previous molecular studies of prey susceptibility have focussed on individual genes/metabolites, we have also undertaken a genome-wide screen for genes of Pseudomonas aeruginosa which contribute to its ability to resist predation. P. aeruginosa is a World Health Organisation priority 1 antibiotic-resistant pathogen. It is metabolically versatile and has an array of pathogenic mechanisms, leading to its prevalence as an opportunistic pathogen. Using a library of nearly 5,500 defined transposon insertion mutants, we screened for "prey genes", which when mutated allowed increased predation by a fluorescent strain of M. xanthus. A set of candidate "prey proteins" were identified, which shared common functional roles and whose nature suggested that predation resistance by P. aeruginosa requires an effective metal/oxidative stress system, an intact motility system, and mechanisms for de-toxifying antimicrobial peptides.
细菌捕食是一种普遍存在且至关重要的生物学过程，它会影响微生物生态系统的群落组成。在已得到充分研究的细菌捕食者中，粘细菌是其中一类，包括模式生物黄色粘球菌。黄色粘球菌的捕食行为涉及抗生素代谢产物和水解酶的分泌，这会导致猎物细胞裂解，并将猎物的营养物质释放到细胞外环境中。由于这种捕食机制具有通用性，黄色粘球菌具有广泛的猎物范围，能够杀死并消耗革兰氏阴性/阳性细菌以及真菌。潜在的猎物生物体已经进化出一系列行为来保护自己免受捕食者的攻击。近年来，多项研究探讨了多种猎物生物体对黄色粘球菌捕食的分子反应。似乎猎物所采用的多种机制可归为数量少得多的几种通用“抗捕食”策略。在这篇小型综述中，我们介绍了有关黄色粘球菌捕食以及猎物生物体如何抵抗捕食的当前知识状态。由于先前对猎物易感性的分子研究集中在单个基因/代谢产物上，我们还对铜绿假单胞菌中有助于其抵抗捕食能力的基因进行了全基因组筛选。铜绿假单胞菌是世界卫生组织确定的1类优先耐药病原体。它具有多种代谢功能，并拥有一系列致病机制，这使其成为一种常见的机会致病菌。我们使用一个包含近5500个确定的转座子插入突变体的文库，筛选了“猎物基因”，这些基因发生突变后会使黄色粘球菌的荧光菌株对其捕食能力增强。我们鉴定出了一组候选“猎物蛋白”，它们具有共同的功能作用，并且其性质表明铜绿假单胞菌的抗捕食需要一个有效的金属/氧化应激系统、一个完整的运动系统以及对抗菌肽进行解毒的机制。
