为了对从猫粪便样品中分离的钩虫虫卵进行种类鉴定,本研究提取该虫卵基因组DNA,根据核糖体内转录间区1(ITS1)的保守序列设计钩虫属引物,通过PCR扩增、克隆、测序、相关软件分析,建立系统进化树,从分子水平对其进行种类鉴定。结果表明扩...为了对从猫粪便样品中分离的钩虫虫卵进行种类鉴定,本研究提取该虫卵基因组DNA,根据核糖体内转录间区1(ITS1)的保守序列设计钩虫属引物,通过PCR扩增、克隆、测序、相关软件分析,建立系统进化树,从分子水平对其进行种类鉴定。结果表明扩增出404 bp DNA片段,测序结果显示该片段包括309 bp ITS1和95 bp的5.8S rDNA,与NCBI中登录的序列进行比对以及采用Clustal X和MEGA5.1软件分析确定该钩虫为锡兰钩虫。这是我国首次建立钩虫的分子鉴定方法,也是40年来再次发现猫源锡兰钩虫,为锡兰钩虫分子生物学和分子流行病学研究奠定了基础。展开更多
Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrola...Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrolases and in the biological control of plant diseases. A fundamental part of the Trichoderma antifungal system consists of a series of genes coding for a surprising variety of extracellular cell wall degrading enzymes (CWDE). Characterisation and identification of strains at the species level is the first step in utilizing the full potential of fungi in specific applications. One aim when isolating Trichoderma strains is to identify those which can be used in new agricultural and industrial applications. In the past it was not uncommon that biocontrol strains were defined as T. harzianum Rifai, due to the limited classification system of the genus Trichoderma. In recent years, several PCR-based molecular techniques have been used to detect and discriminate among microorganisms. Sequence analysis of the ITS regions of the ribosomal DNA and gene fragments as those corresponding to tef1 gene have been helpful in the neotypification, description and characterization of species in the genus Trichoderma. Another useful method for the identification of Trichoderma strains is the randomly amplified polymorphic DNA (RAPD) technique. Isozyme polymorphisms evaluation of five putative extracellular lytic enzymes loci (β-1,3-glucanase, β-1,6-glucanase, cellulase, chitinase and protease antivities) were carried out using representative strains of defined molecular groups. CWDE groupings obtained from biocontrol strains are discussed in relation to their phylogenetic location and antifungal activities. Compiling morphological, biochemical and sequence information data into a common database would provide a useful resource that could be used to accurately name new haplotypes identified in the future and correctly place them within the genus Trichoderma.展开更多
Two forms of A. halimus shrubs: erect habit (A. halimus) and bushy habit shrub (A. schweinfurthii) are used naturally isolated by a considerable distance from each other and occupy the same area. To explore the effect...Two forms of A. halimus shrubs: erect habit (A. halimus) and bushy habit shrub (A. schweinfurthii) are used naturally isolated by a considerable distance from each other and occupy the same area. To explore the effect of natural isolation on the genetic basis of the two forms, Start Codon Targeted (SCoT) and the phylogenetic relationships of A. halimus by sequencing ITS1-5.8S-ITS2 regions of the ribosomal DNA are used. Significant isolation-by-distance relationship was found (r = 0.62, P = 0.001). Soil factors did not influence molecular variations. The natural isolation of A. halimus habitats restricts gene flow among the populations and the observed high within-population genetic diversity (74.19%) in this species is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. The UPGMA analysis of the SCoT results showed that all the studied populations were divided into two discrete genetic groups with significant separation of the two forms in Burg El-Arab area (Populations 1 and 2) and insignificant separation between two forms in El-Hammam area (population 5 and 6). The sequencing of the ITS1-5.8S-ITS2 rDNA regions also showed the insignificant separation of the two A. halimus forms. We conclude that gene flow depending on habitat fragmentation was the main factor affecting the population genetic differentiation. We suggest that the two forms do not merit specific rank in presence of interference between the two forms and absence of a breeding barrier fail to separate the different populations when they become sympatric.展开更多
文摘为了对从猫粪便样品中分离的钩虫虫卵进行种类鉴定,本研究提取该虫卵基因组DNA,根据核糖体内转录间区1(ITS1)的保守序列设计钩虫属引物,通过PCR扩增、克隆、测序、相关软件分析,建立系统进化树,从分子水平对其进行种类鉴定。结果表明扩增出404 bp DNA片段,测序结果显示该片段包括309 bp ITS1和95 bp的5.8S rDNA,与NCBI中登录的序列进行比对以及采用Clustal X和MEGA5.1软件分析确定该钩虫为锡兰钩虫。这是我国首次建立钩虫的分子鉴定方法,也是40年来再次发现猫源锡兰钩虫,为锡兰钩虫分子生物学和分子流行病学研究奠定了基础。
文摘Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrolases and in the biological control of plant diseases. A fundamental part of the Trichoderma antifungal system consists of a series of genes coding for a surprising variety of extracellular cell wall degrading enzymes (CWDE). Characterisation and identification of strains at the species level is the first step in utilizing the full potential of fungi in specific applications. One aim when isolating Trichoderma strains is to identify those which can be used in new agricultural and industrial applications. In the past it was not uncommon that biocontrol strains were defined as T. harzianum Rifai, due to the limited classification system of the genus Trichoderma. In recent years, several PCR-based molecular techniques have been used to detect and discriminate among microorganisms. Sequence analysis of the ITS regions of the ribosomal DNA and gene fragments as those corresponding to tef1 gene have been helpful in the neotypification, description and characterization of species in the genus Trichoderma. Another useful method for the identification of Trichoderma strains is the randomly amplified polymorphic DNA (RAPD) technique. Isozyme polymorphisms evaluation of five putative extracellular lytic enzymes loci (β-1,3-glucanase, β-1,6-glucanase, cellulase, chitinase and protease antivities) were carried out using representative strains of defined molecular groups. CWDE groupings obtained from biocontrol strains are discussed in relation to their phylogenetic location and antifungal activities. Compiling morphological, biochemical and sequence information data into a common database would provide a useful resource that could be used to accurately name new haplotypes identified in the future and correctly place them within the genus Trichoderma.
文摘Two forms of A. halimus shrubs: erect habit (A. halimus) and bushy habit shrub (A. schweinfurthii) are used naturally isolated by a considerable distance from each other and occupy the same area. To explore the effect of natural isolation on the genetic basis of the two forms, Start Codon Targeted (SCoT) and the phylogenetic relationships of A. halimus by sequencing ITS1-5.8S-ITS2 regions of the ribosomal DNA are used. Significant isolation-by-distance relationship was found (r = 0.62, P = 0.001). Soil factors did not influence molecular variations. The natural isolation of A. halimus habitats restricts gene flow among the populations and the observed high within-population genetic diversity (74.19%) in this species is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. The UPGMA analysis of the SCoT results showed that all the studied populations were divided into two discrete genetic groups with significant separation of the two forms in Burg El-Arab area (Populations 1 and 2) and insignificant separation between two forms in El-Hammam area (population 5 and 6). The sequencing of the ITS1-5.8S-ITS2 rDNA regions also showed the insignificant separation of the two A. halimus forms. We conclude that gene flow depending on habitat fragmentation was the main factor affecting the population genetic differentiation. We suggest that the two forms do not merit specific rank in presence of interference between the two forms and absence of a breeding barrier fail to separate the different populations when they become sympatric.
基金Supported by the National Natural Science Foundation of China(31501845,31672280,31970409)Chongqing Natural Science Foundation(cstc2017jcyjAX0165 and cstc2018jcyjAX0738)+1 种基金Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2018108)Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN201900505)。
