To reveal the intraspecific evolution of Leptospirillum ferriphilum isolates which thrived in industrial bioleaching ecosystems and acid mine drainages,genome sequences of L.ferriphilum YSK,L.ferriphilum DX and L.ferr...To reveal the intraspecific evolution of Leptospirillum ferriphilum isolates which thrived in industrial bioleaching ecosystems and acid mine drainages,genome sequences of L.ferriphilum YSK,L.ferriphilum DX and L.ferriphilum ZJ were determined to compare with complete genome of L.ferriphilum ML-04.The genome comparisons reveal that extensive intraspecific variation occurs in their genomes,and that the loss and insertion of novel gene blocks of probable phage origin may mostly contribute to heterogeneity of gene content among L.ferriphilum genomes.Surprisingly,a nif gene cluster is identified in L.ferriphilum YSK and L.ferriphilum ZJ genomes.Intensive analysis and further experiments indicate that the nif gene cluster in L.ferriphilum YSK inherits from ancestor rather than lateral gene transfer.Overall,results suggest that the population of L.ferriphilum undergoes frequent genetic recombination,resulting in many closely related genome types in recent evolution.The combinatorial processes profoundly shape their physiologies and provide the basis for adaptation to different niches.展开更多
为了解引起2017年10月甘肃省兰州市一起疱疹性咽峡炎(Herpangina,HA)暴发疫情的致病病原体及其病原学特征,对采集的患儿的37份咽拭子样本开展病毒分离培养,然后对分离到的毒株采取一代测序获取VP1区全长核苷酸序列,根据分子定型的方法...为了解引起2017年10月甘肃省兰州市一起疱疹性咽峡炎(Herpangina,HA)暴发疫情的致病病原体及其病原学特征,对采集的患儿的37份咽拭子样本开展病毒分离培养,然后对分离到的毒株采取一代测序获取VP1区全长核苷酸序列,根据分子定型的方法进行肠道病毒型别鉴定。根据VP1区核苷酸差异选择3个毒株进行二代测序,获取全基因组序列。使用MEGA软件(版本号11.0)进行病毒的核苷酸,氨基酸相似性分析,VP1区的氨基酸突变位点分析,并构建系统发育树,使用Simplot(版本号3.5.1)软件进行病毒重组分析。本次疫情中分离到的毒株鉴定为柯萨奇病毒A2型(Coxsackievirus A 2, CV-A2),分子分型显示属于D基因型,且VP1区第102位氨基酸发生了丙氨酸到甘氨酸(A102G)的突变,与省内2014-2015年分离到的两株CV-A2毒株在该位置的突变不同。重组分析发现,病毒在P2区和P3区发生了以CV-A4为主的重组事件。本次疫情的致病病原体CV-A2存在着VP1区氨基酸A102G的特征性变异及P2区和P3区的重组,需要加强对肠道病毒的变异和重组的监测和研究,以提升预警能力。展开更多
猪繁殖和呼吸综合征(porcine reproductive and respiratory syndrome,PRRS)是一种发病迅速、高度传染的病毒性传染病。自20世纪90年代在我国发现以后,逐渐广泛流行,不同毒株也相继分离报道。21世纪初的高致病性变异毒株的出现,更是席...猪繁殖和呼吸综合征(porcine reproductive and respiratory syndrome,PRRS)是一种发病迅速、高度传染的病毒性传染病。自20世纪90年代在我国发现以后,逐渐广泛流行,不同毒株也相继分离报道。21世纪初的高致病性变异毒株的出现,更是席卷全国各地。各个品种,不同年龄,不同用途的猪只均可感染。随后毒株NADC30-like的出现,增加了猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的多样性。并且PRRSV高基因性的突变和不同毒株间相互重组导致新的变异毒株频繁出现。现有商用疫苗不能提供足够的保护力,给养猪业造成了巨大的损失。因此针对我国的猪繁殖和呼吸综合征流行现状进行综述,为进一步做好该病的防控提供参考。展开更多
Major histocompatibility complex （MHC） is a family of highly polymorphic genes activating adaptive immunity in vertebrates. However, the underlying mecha- nism of MHC evolution is still not fully understood. In this...Major histocompatibility complex （MHC） is a family of highly polymorphic genes activating adaptive immunity in vertebrates. However, the underlying mecha- nism of MHC evolution is still not fully understood. In this study, we investigated genetic variation of three classical MHC class I genes in the giant panda （Ailuropoda mela- noleuca） and tested for selection effect and recombination event across exonic and intronic sequences to understand maintenance mechanism of polymorphism at Aime-MHC class I genes. In total, we isolated 21 MHC class I haplotypes （exon 2-intron 2-exon 3） from 46 captive giant pandas, of which eight were for Aime-C, seven for Aime-I and six for Aime-L; however, we only identified six unique sequences from these haplotypes. The subsequent maximum-likeli- hood and Chi-square analyses both detected evidence of recombination acting on the 21 haplotypes. These results indicate that the giant panda still retains a relatively high adaptive variation at Aime-MHC-I genes, and that the intronic segments have been homogenized along evolu- tionary time by recombination and subsequent genetic drift.We calculated nucleotide substitution rates of the antigen- binding regions （exons 2 and 3） and the noncoding intron 2, and found two pieces of evidence supporting the presence of balancing selection in the giant panda： an excess of nonsynonymous over synonymous substitutions at the antigen-binding sites, and an obviously higher synonymous substitutions in the exons than nucleotide substitutions in the intron. Thus, this study reveals that balancing selection and recombination together shape the diversity pattern at Aime- MHC-I loci of the giant panda.展开更多
基金Project(2018YFC1801804)supported by the National Key R&D Program of ChinaProjects(2016JJ3146,2017JJ3160)supported by the Natural Science Foundation of Hunan Province,China。
文摘To reveal the intraspecific evolution of Leptospirillum ferriphilum isolates which thrived in industrial bioleaching ecosystems and acid mine drainages,genome sequences of L.ferriphilum YSK,L.ferriphilum DX and L.ferriphilum ZJ were determined to compare with complete genome of L.ferriphilum ML-04.The genome comparisons reveal that extensive intraspecific variation occurs in their genomes,and that the loss and insertion of novel gene blocks of probable phage origin may mostly contribute to heterogeneity of gene content among L.ferriphilum genomes.Surprisingly,a nif gene cluster is identified in L.ferriphilum YSK and L.ferriphilum ZJ genomes.Intensive analysis and further experiments indicate that the nif gene cluster in L.ferriphilum YSK inherits from ancestor rather than lateral gene transfer.Overall,results suggest that the population of L.ferriphilum undergoes frequent genetic recombination,resulting in many closely related genome types in recent evolution.The combinatorial processes profoundly shape their physiologies and provide the basis for adaptation to different niches.
文摘为了解引起2017年10月甘肃省兰州市一起疱疹性咽峡炎(Herpangina,HA)暴发疫情的致病病原体及其病原学特征,对采集的患儿的37份咽拭子样本开展病毒分离培养,然后对分离到的毒株采取一代测序获取VP1区全长核苷酸序列,根据分子定型的方法进行肠道病毒型别鉴定。根据VP1区核苷酸差异选择3个毒株进行二代测序,获取全基因组序列。使用MEGA软件(版本号11.0)进行病毒的核苷酸,氨基酸相似性分析,VP1区的氨基酸突变位点分析,并构建系统发育树,使用Simplot(版本号3.5.1)软件进行病毒重组分析。本次疫情中分离到的毒株鉴定为柯萨奇病毒A2型(Coxsackievirus A 2, CV-A2),分子分型显示属于D基因型,且VP1区第102位氨基酸发生了丙氨酸到甘氨酸(A102G)的突变,与省内2014-2015年分离到的两株CV-A2毒株在该位置的突变不同。重组分析发现,病毒在P2区和P3区发生了以CV-A4为主的重组事件。本次疫情的致病病原体CV-A2存在着VP1区氨基酸A102G的特征性变异及P2区和P3区的重组,需要加强对肠道病毒的变异和重组的监测和研究,以提升预警能力。
文摘猪繁殖和呼吸综合征(porcine reproductive and respiratory syndrome,PRRS)是一种发病迅速、高度传染的病毒性传染病。自20世纪90年代在我国发现以后,逐渐广泛流行,不同毒株也相继分离报道。21世纪初的高致病性变异毒株的出现,更是席卷全国各地。各个品种,不同年龄,不同用途的猪只均可感染。随后毒株NADC30-like的出现,增加了猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的多样性。并且PRRSV高基因性的突变和不同毒株间相互重组导致新的变异毒株频繁出现。现有商用疫苗不能提供足够的保护力,给养猪业造成了巨大的损失。因此针对我国的猪繁殖和呼吸综合征流行现状进行综述,为进一步做好该病的防控提供参考。
基金supported by a special grant(SG1411)for the giant panda from the State Forestry Administration of China
文摘Major histocompatibility complex （MHC） is a family of highly polymorphic genes activating adaptive immunity in vertebrates. However, the underlying mecha- nism of MHC evolution is still not fully understood. In this study, we investigated genetic variation of three classical MHC class I genes in the giant panda （Ailuropoda mela- noleuca） and tested for selection effect and recombination event across exonic and intronic sequences to understand maintenance mechanism of polymorphism at Aime-MHC class I genes. In total, we isolated 21 MHC class I haplotypes （exon 2-intron 2-exon 3） from 46 captive giant pandas, of which eight were for Aime-C, seven for Aime-I and six for Aime-L; however, we only identified six unique sequences from these haplotypes. The subsequent maximum-likeli- hood and Chi-square analyses both detected evidence of recombination acting on the 21 haplotypes. These results indicate that the giant panda still retains a relatively high adaptive variation at Aime-MHC-I genes, and that the intronic segments have been homogenized along evolu- tionary time by recombination and subsequent genetic drift.We calculated nucleotide substitution rates of the antigen- binding regions （exons 2 and 3） and the noncoding intron 2, and found two pieces of evidence supporting the presence of balancing selection in the giant panda： an excess of nonsynonymous over synonymous substitutions at the antigen-binding sites, and an obviously higher synonymous substitutions in the exons than nucleotide substitutions in the intron. Thus, this study reveals that balancing selection and recombination together shape the diversity pattern at Aime- MHC-I loci of the giant panda.
