单染色体霍乱弧菌基因组学与生物学特征分析  

Genomic and biological characteristics of a Vibrio cholerae strain with chromosome fusion

作　　者：蒋羽 赵文轩 宋敬东[2] 赵硕 逄波[1] 阚飙[1] JIANG Yu;ZHAO Wenxuan;SONG Jingdong;ZHAO Shuo;PANG Bo;KAN Biao(National Institute for Communicable Disease Prevention and Control,Chinese Center for Disease Control and Prevention,State Key Laboratory of Communicable Disease Prevention and Control,Beijing 102206,China;不详)

机构地区：[1]中国疾病预防控制中心传染病预防控制所,传染病预防控制国家重点实验室,北京102206 [2]中国疾病预防控制中心病毒病预防控制所

出　　处：《中国预防医学杂志》2023年第6期587-593,共7页Chinese Preventive Medicine

基　　金：国家科技重大专项(2018ZX10714002)。

摘　　要：目的 研究1株罕见的两条染色体融合为单染色体的霍乱弧菌菌株的基因组及其生物学特征,并与典型的具有两个染色体的霍乱弧菌进行比较。方法 通过短读长和长读长测序相结合的方法测定及分析单染色体菌株VC6047的基因组特征,分析融合方式。通过透射电镜观察菌体形态,观察不同培养温度、pH值、盐浓度和M9以及LB培养基下菌株的生长状况,分析生物膜形成能力以及进入活的非可培养状态(viable but non-culturable, VBNC)的生物学特征。结果 菌株VC6047呈现典型的弧菌特征,染色体的融合位置对应于霍乱弧菌大、小染色体的att B位点(染色体附着位点),也是霍乱弧菌丝状溶源性噬菌体CTXΦ整合的位置。该菌株与第七次大流行菌株处于不同进化分支。培养18 h后,25℃LB培养基条件下以及在37℃,4.0%和5.0%盐浓度LB培养基中菌株VC6047生长高于对比菌株。菌株VC6047仍然具有生物膜形成能力,但相比较于其基因组高度同源的,仍为两个染色体的菌株,菌株VC6047进入VBNC的速率加快,冷适应能力有所降低。结论 大小染色体融合菌株仍基本保持应对优劣环境压力的能力,但发生了一些环境压力适应变化,为菌株染色体融合可能的促成压力研究和微环境适应提供了基础认识。Objective To analyze the genomic and biological characteristics of a rare Vibrio cholerae strain harboring a single chromosome formed by the natural fusion of two chromosomes and to compare with typical V.cholerae strains with two chromosomes.Methods The genomic and chromosomal fusion characteristics of a VC6047 strain with single chromosome were analyzed combining short-and long-read sequencing.Morphological characteristics of V.cholerae were observed using transmission electron microscopy.Growth status of the strain were documented under different conditions including temperature,pH,salt concentration,M9 and LB,as well as the biofilm formation capability and its biological behavior at a viable but non-culturable(VBNC)state were analyzed.Results The VC6047 strain demonstrated typical Vibrio morphology.The location of the fusion corresponded to the attB(dromosome attachment site)site at the large and small chromosomes,where the filamentous,lysogenic CTXΦbacteriophage integrated in V.cholerae.Strain VC6047 was in an independent evolutionary branch in phylogenetic tree compared to the seventh-pandemic strain.After 18 h of incubation,the growth of VC6047 cultured in LB medium at 25℃as well as in LB medium with 4.0%and 5.0%salt concentrations at 37℃was higher than the control strains.VC6047 maintained the biofilm-forming ability,while presented a reduced capacity to adopt to coldness due to an accelerated rate entering a VBNC state compared to highly homologous strains with two chromosomes.Conclusions Strains with a single chromosome resulted from natural fusion maintained the basic ability to cope with environmental stress,but not without some changes in its adaptation to environmental stress.Study on this rare strain may provide basic understanding of the possible fusiontriggering factors in environmental stresses and microenvironmental adaptation.

关 键 词：霍乱弧菌 染色体 融合 生长 attB位点 

分 类 号：R378.3[医药卫生—病原生物学]