The predatory behavior of Myxococcus xanthus has attracted extensive attention due to its unique social traits and inherent biological activities. In addition to group hunting, individual M. xanthus cells are able to kill and lyse prey cells; however, there is little understanding of the dynamics of solitary predation. In this study, by employing a bacterial tracking technique, we investigated M. xanthus predatory dynamics on Escherichia coli at the single-cell level. The killing and lysis of E. coli by a single M. xanthus cell was monitored in real time by microscopic observation, and the plasmolysis of prey cells was identified at a relatively early stage of solitary predation. After quantitative characterization of their solitary predatory behavior, M. xanthus cells were found to respond more dramatically to direct contact with live E. coli cells than heat-killed or UV-killed cells, showing slower predator motion and faster lysing of prey. Among the three contact-dependent killing modes classified according to the major subareas of M. xanthus cells in contact with prey, leading pole contact was observed most. After killing the prey, approximately 72% of M. xanthus cells were found to leave without thorough degradation of the lysed prey, and this postresidence behavior is described as a lysis-leave pattern, indicating that solitary predation has low efficiency in terms of prey-cell consumption. Our results provide a detailed description of the single-cell level dynamics of M. xanthus solitary predation from both prey and predator perspectives.

IMPORTANCE Bacterial predation plays multiple essential roles in bacterial selection and mortality within microbial ecosystems. In addition to its ecological and evolutionary importance, many potential applications of bacterial predation have been proposed. The myxobacterium Myxococcus xanthus is a well-known predatory member of the soil microbial community. Its predation is commonly considered a collective behavior comparable to a wolf pack attack; however, individual M. xanthus cells are also able to competently lead to the lysis of a prey cell. Using a bacterial tracking technique, we are able to observe and analyze solitary predation by M. xanthus on Escherichia coli at the single-cell level and reveal the dynamics of both predator and prey during the process. The present study will not only provide a comprehensive understanding of M. xanthus solitary predation but also help to explain why M. xanthus often displays multicellular characteristic predatory behaviors in nature, while a single cell is capable of predation.

由于其独特的社会特征和固有的生物活性，其致死性行为引起了广泛的关注。除了集体狩猎外，单个的M. xanthus细胞还能够杀死和溶解猎物细胞。但是，对孤立捕食的动力学知之甚少。在这项研究中，通过采用细菌跟踪技术，我们在单细胞水平上调查了黄腐分支杆菌在大肠杆菌上的掠食动力学。单株黄腐杆菌杀死并裂解大肠杆菌通过显微镜观察实时监测monitored鱼细胞，并在相对较早的孤立捕食阶段鉴定出cells肉的胞质溶解。在定量表征其单独的掠食行为后，与热灭活或被紫外线杀死的细胞相比，黄腐杆菌对直接接触活的大肠杆菌细胞的反应要大得多，表现出较慢的食肉动物运动和较快的猎物裂解。在按与猎物接触的黄麻线虫细胞的主要子区域分类的三种接触依赖性杀伤模式中，观察到引导杆接触最多。杀死猎物后，大约有X.hu. xanthus的72％发现细胞离开后，裂解的猎物没有完全降解，这种居留后行为被描述为裂解-离开模式，表明就捕食细胞的消耗而言，单独的捕食效率较低。我们的结果从猎物和捕食者的角度提供了详细的描述黄单胞菌孤立捕食的单细胞水平动力学。

重要信息细菌捕食在微生物生态系统内的细菌选择和死亡率中起着多种重要作用。除了其生态和进化重要性外，还提出了细菌捕食的许多潜在应用。粘菌黄霉（Myxococcus xanthus）是土壤微生物群落的众所周知的掠食性成员。它的掠食通常被认为是与狼群攻击相当的集体行为。然而，单独的黄腐支原体细胞也能够有效地导致猎物细胞的裂解。使用细菌跟踪技术，我们能够观察和分析黄腐分支杆菌在大肠杆菌上的孤立捕食行为在单细胞水平上揭示了捕食者和猎物在此过程中的动态。本研究将不仅提供对黄单胞菌单独捕食的全面理解，而且还将有助于解释为什么黄单胞菌在自然界中经常表现出多细胞特征性的捕食行为，而单个细胞却具有捕食能力。