基于18S-ITS1-5.8S序列的吉富罗非鱼群体遗传多样性分析

运用PCR技术扩增吉富罗非鱼选育群体第20和21世代18S-ITS1-5.8S序列,分析二序列的遗传变异。结果表明,18S-ITS1-5.8S序列中,18S、内转录间隔区(ITS)1和5.8S序列分别为156、483~540、64 bp,主要变异位点位于ITS1中;基于ITS1序列的第20代吉富罗非鱼(17尾)群体内遗传距离为0.001,保守位点530个,变异位点10个,单倍型4个,单倍型多样性为0.331±0.143,核苷酸多样性为0.002,平均核苷酸差异为1.279;基于ITS1的第21代吉富罗非鱼(42尾)群体内遗传距离为0.015,6个个体存在严重碱基缺失现象,保守位点492个,变异位点49个,单倍型12个,单倍型多样性为0.638±0.083,核苷酸多样性为0.014,平均核苷酸差异为6.945。ITS序列在该两吉富罗非鱼群体中变异较小,基于ITS1序列分析的两代群体遗传多样性水平较低。

基于核糖体RNA ITS1-5.8S-ITS2基因序列的十二指肠钩虫分子系统发育分析

目的通过克隆十二指肠钩虫的ITS1-5.8S-ITS2,初步分析钩口属的系统发育,构建基于ITS1、ITS2的圆线目线虫的系统进化树,为进一步研究其遗传进化关系奠定基础。方法从厦门海沧东孚镇收集标本,分离,形态鉴定为十二指肠钩虫,分别克隆了供试钩虫的ITS1-5.8S-ITS2序列,经NCBI网站的BLAST比对以及基于ITS1和ITS2序列的钩口属的系统发育分析。结果供试钩虫的ITS1、5.8S和ITS2序列,它们的长度分别为366bp、153bp和221bp,登陆http://www.ncbi.nlm.nih.gov进行BLAST,在数据库中没有与之相匹配的序列,将获得的序列作为新的序列上传至GenBank中进行注册,各序列的GenBank登录号分别为:5.8SrRNA基因:EU344796、ITS1-5.8S-ITS2:EU344797。结论从系统进化树中,本实验的供试十二指肠钩虫均与GenBank中已公布的十二指肠钩口线虫自然聚类在一起。

Genetic Variation among Fragmented Populations of Atriplex halimus L. Using Start Codon Targeted (SCoT) and ITS1-5.8S-ITS2 Region Markers

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.

On four closely related hypotrichous ciliates(Protozoa,Ciliophora,Spirotrichea):molecular characters,interspecific relationships and phylogeny defined with multigene sequence information

In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha sp.,and A.manca,were compared and analyzed using ITS2 secondary structures,ITS1-5.8S-ITS2 region and SSrRNA gene sequences.The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced,and they shared sequence identities ranging from 68.0% to 90.1%,while two populations of Anteholosticha sp.differed in three nucleotides（sequence identity 99.8%）.There were several minor differences among ITS2 secondary structures of these species,while two populations of Anteholosticha sp.had the identical secondary structure.Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms（Neighbor-Joining,Maximum Parsimony and Bayesian） revealed similar topologies.The results show that：（1） Holosticha bradburyae and H.diademata firmly clustered together with strong bootstrap supports,forming a sister clade with Anteholosticha sp.,（2） Anteholosticha appeared to be a paraphyletic assemblage,in which the morphotype A.manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp.Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha,nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.

沙棘果酒专用酵母菌的分子生物学鉴定及其应用研究

目前工业上尚无酿造沙棘果酒的专用酵母菌,因此,筛选出适合酿造沙棘果酒的优良酵母菌尤为必要。利用ITS1-5.8S-ITS2 rDNA序列分析及构建系统发育树对自选酵母菌Y23进行分子生物学鉴定。结果表明,克隆的自选酵母菌Y23的5.8S-ITS rDNA序列(GenBank接受号:FJ793809)全长874bp。自选酵母菌Y23与Saccharomyces cerevisiae CB S423T(AM262829)的遗传距离最近,两者之间的同源性为100%,因此,鉴定酵母菌Y23为酵母属(Sacchar omyces)酿酒酵母(Sacchar omyces cerevisiae)。通过响应面分析法研究初始糖度、发酵温度、接种量对自选酵母菌Y23酿造沙棘果酒品质的影响,得出沙棘果酒质量与影响因素间的回归模型,并根据模型进行工艺参数优化。结果表明,接种量对沙棘果酒质量的影响极显著(P<0.01)。利用自选酵母菌Y23酿造沙棘果酒的最佳工艺参数是:初始糖度19.9%、发酵温度25.4℃、接种量10.3%。

两株盐生海芦笋内生真菌的分离与鉴定

对分离自江苏盐城大丰港盐碱地野生海芦笋的两株嗜盐内生真菌进行分离鉴定,提取基因组DNA后分别对18S rDNA和rDNA ITS1-5.8S-ITS4区域进行PCR扩增,基因测序并进行同源性分析,构建进化树并进行系统发育分析,结合形态学观察,将该两株菌分别鉴定为维管束茎点霉(Phoma tracheiphila)与镰刀菌属(Fusarium sp.)。

一株产阿魏酸酯酶青霉菌株的筛选、鉴定及生长特征

从腐烂的木质纤维中筛选了一株产阿魏酸酯酶的菌株HDFE1,根据其形态特征、rDNAITS1-5.8S-ITS2序列及系统发育分析,鉴定菌株HDFE1为青霉属的橘青霉(Penicillium citrinum Thom)。菌株HDFE1最适生长温度为30°C,最适生长pH为6.0。该菌株在30°C、pH6.0、200r/min培养60h时,阿魏酸酯酶酶活力为最高,达20.75U/L。