Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
University of the Chinese Academy of Sciences, Beijing, 100039, China.
Appl Microbiol Biotechnol. 2018 Dec;102(24):10691-10702. doi: 10.1007/s00253-018-9424-4. Epub 2018 Oct 25.
Lysinibacillus sphaericus has great application potential not only in the biocontrol of mosquitoes but also in the bioremediation of toxic metals. Phages contribute to the genetic diversity and niche adaptation of bacteria, playing essential roles in their life cycle, but may also cause economic damage for industrially important bacteria through phage contamination during fermentation. In this study, the L. sphaericus phage vB_LspM-01, which belongs to the Myoviridae family, was isolated and characterized. Results showed that vB_LspM-01 could specifically infect most tested L. sphaericus isolates but was not active against isolates belonging to other species. Furthermore, phage-born endolysin exhibited a broader antimicrobial spectrum than the host range of the phage. The vB_LspM-01 genome had no obvious similarity with that of its host, and ca. 22.6% of putative ORFs could not get a match with the public databases. Phylogenic analysis based on the putative terminase large subunit showed high similarity with the phages identified with pac-type headful packaging. The vB_LspM-01 encoding genes were only detected in a tiny percentage of L. sphaericus C3-41 individual cells in the wild population, whereas they showed much higher frequency in the resistant population grown within the plaques; however, the phage genes could not be stably inherited during host cell division. Additionally, the vB_LspM-01 encoding genes were only detected in the host population during the logarithmic growth phase. The mitomycin C induction helped the propagation and lysogeny-lysis switch of vB_LspM-01. The study demonstrated that vB_LspM-01 can be present in a pseudolysogenic state in L. sphaericus C3-41 populations.
球形芽孢杆菌具有巨大的应用潜力，不仅在蚊虫的生物防治方面，而且在有毒金属的生物修复方面。噬菌体有助于细菌的遗传多样性和生态位适应，在它们的生命周期中发挥着重要作用，但在发酵过程中噬菌体污染也可能对工业上重要的细菌造成经济损失。在这项研究中，分离并表征了属于肌病毒科的球形芽孢杆菌噬菌体 vB_LspM-01。结果表明，vB_LspM-01 可以特异性感染大多数测试的球形芽孢杆菌分离株，但对属于其他物种的分离株没有活性。此外，噬菌体产生的溶菌酶表现出比噬菌体宿主范围更广泛的抗菌谱。vB_LspM-01 基因组与宿主没有明显的相似性，大约 22.6%的假定 ORFs 与公共数据库没有匹配。基于假定终止酶大亚基的系统发育分析显示与 pac 型头部满载包装的噬菌体高度相似。vB_LspM-01 编码基因仅在野生种群中的球形芽孢杆菌 C3-41 单个细胞中以极小的比例检测到，而在斑块中生长的抗性种群中则显示出更高的频率；然而，噬菌体基因在宿主细胞分裂过程中不能稳定遗传。此外，vB_LspM-01 编码基因仅在宿主对数生长期中检测到。丝裂霉素 C 的诱导有助于 vB_LspM-01 的增殖和溶原性裂解转换。研究表明，vB_LspM-01 可以在球形芽孢杆菌 C3-41 种群中以伪溶原状态存在。
