检索结果-南通市图书馆

Characterization of a novel toxin-antitoxin module, VapBC, encoded by Leptospira interrogans chromosome

Cell Research 2004年第3期14卷 208-216页

作者： Yi Xuan ZHANG, Xiao Kui GUO, Chuan WU, Bo BI, Shuang Xi REN, Chun Fu WU, Guo Ping ZHAO Pharmaceutical Department, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe District, Shenyang 110016, China. Research Center of Biotechnology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 500 Caobao Road, Shanghai 200233, China. Department of Microbiology and Parasitology, Shanghai Second Medical University, 280 Chongqingnan Road, Shanghai 200025, China. Chinese National Human Genome Center at Shanghai (CHGCS), 250 Bibo Road, ZhangJiang High Tech Park, Shanghai, 201203, China. Pharmaceutical Department Shenyang Pharmaceutical University 103 Wenhua Road Shenhe District Shenyang China Research Center of Biotechnology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai China Department of Microbiology and Parasitology Shanghai Second Medical University Shanghai China Chinese National Human Genome Center at Shanghai (CHGCS) 250 Bibo Road ZhangJiang High Tech Park Shanghai China

Comparative genomic analysis of the coding sequences （CDSs） of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid sequences and operon organizations. Expression of single vapC gene in Escherichia coli resulted in inhibition of bacterial growth, whereas co-expression of vapBC restored the growth effectively. This phenotype is typical for three other characterized toxin-antitoxin systems of bacteria, i.e., mazEF[1], relBE[2] and chpIK[3]. The VapC proteins of bacteria and a thermophilic archeae, Solfolobus tokodaii, form a structurally distinguished group of toxin different from the other known toxins of bacteria. Phylogenetic analysis of both toxins and antitoxins of all categories indicated that although toxins were evolved from divergent sources and may or may not follow their speciation.paths （as indicated by their 16s RNA sequences）, co-evolution with their antitoxins was obvious.

关键词： Leptospria toxin-antitoxin system VapBC co-evolution speciation.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The evolution of aposematism is accompanied by increased diversification

引用

Integrative Zoology 2008年第3期3卷 149-156页

作者： Kara PRZECZEK Carla MUELLER Steven M.VAMOSI Department of Biological Sciences University of CalgaryCalgaryCanada

Although the use of distinct colors to indicate unprofitability to predators(i.***.aposematism)is commonly thought of as an adaptation,our knowledge of its macroevolutionary effects is limited.Because aposematism is expected to decrease attacks by predators,we hypothesized that aposematic lineages should be larger on average than their non-aposematic sister groups because of the decreased probability of extinction and/or increased probability of speciation.i.***.increased diversification).The results of our sister-group analysis are consistent with the hypothesis that the evolution of aposematism is accompanied by increased diversification of lineages,with the aposematic focal group having more species in 11 of 14 pairs of sister groups.Despite the apparent advantages of reduced predation risk on diversification rates,the evolution of aposematism is relatively rare and reversions to a cryptic state are not uncommon.In addition to the difficulties in evolving a trait that initially decreases the survivorship of prey among naïve predators,we discuss other factors that may limit the apparent prevalence and success of aposematism.It is hoped that the results of our analysis will encourage further analyses of the phylogenetic relationships among aposematic groups and their relatives,and of the evolutionary time scales over which the benefits of aposematism are the greatest to lineages with this condition.

关键词： aposematism diversification predation sister-group comparisons speciation.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

An integrated assessment of a group with complex systematics: the Iberomaghrebian lizard genus Podarcis (Squamata, Lacertidae)

引用

Integrative Zoology 2008年第4期3卷 247-266页

作者： Miguel A.CARRETERO CIBIO Reseach Center in Biodiversity and Genetic ResourcesCampus Agrário de Vair鉶4485-661VairaoPortugal

A critical review of the evolutionary biology of Iberian and North African lizard members of the genus Podarcis(Lacertidae)based on phylogeny,phylogeography,morphometrics,behavior,ecology and physiology is presented.The Iberomaghrebian region is inhabited by at least 12 different evolutionary lineages that group into a monophyl-etic clade(except Podarcis muralis).In contrast to the current taxonomy,the saxicolous‘Podarcis hispanica’is paraphyletic with respect to Podarcis bocagei and Podarcis carbonelli,two currently recognized species.Nodes in the phylogenetic tree are deep,resulting from old divergences,clearly preceding the Pleistocene.Nevertheless,more recent range changes as a result of glaciations are also evident.The most plausible evolutionary scenario for this group indicates both vicariant and dispersal events.Although parapatry between lineages is the rule,sympatry and even syntopy are frequent,but usually between ground-dwelling and saxicolous forms.Contacts between forms with similar habitat use are rare and local.Morphological distinctiveness between lineages has been demonstrated,indicating historical constraints.However,other characters have repeatedly evolved under similar environmental pressures independently of the evolutionary lineage.Strong sexual dimorphism derives from sexual selection and is attained before sexual maturity,although developmental restrictions exist.Variation between popu-lations is also important and derives from local variation in both natural(habitat,climate)and sexual(density)selective pressures.Evidence for short-term changes has already been found,particularly in insular populations.Reproductive isolation between syntopic forms and partner recognition are based on male–male competition and on visual and chemical recognition of females by conspecific males.Despite this ancient diversification,most forms maintain a degree of reproductive compatibility.Hybridisation may occur,but is limited,and there is evidence of selection against hybrids.The ecological analysis present

关键词： Morphometrics Mediterranean basin phylogeny Podarcis reproductive isolation speciation.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：