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The intestinal bacteria of vertebrates form a close relationship with their host.External and internal conditions of the host,including its habitat,affect the intestinal bacterial community.Similarly,the intestinal bacterial community can,in turn,influence the host,particularly with respect to disease resistance.We compared the intestinal bacterial communities of grass carp that were collected from farm-ponds or a lake.We conducted denaturing gradient gel electrophoresis of amplified 16S rRNA genes,from which 66 different operational taxonomic units were identified.Using both the unweighted pair-group method with arithmetic means clustering and principal component analysis ordination,we found that the intestinal bacterial communities from the two groups of pond fish were clustered together and inset into the clusters of wild fish,except for DF-7,and there was no significant correlation between genetic diversity of grass carp and their intestinal bacterial communities(Mantel one-tailed test,R=0.157,P=0.175).Cetobacterium appeared more frequently in the intestine of grass carp collected from pond.A more thorough understanding of the role played by intestinal microbiota on fish health would be of considerable benefit to the aquaculture industry. 相似文献
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以三峡库区所设A、B、C、D、E、F和G等7个站点为研究区域,利用RAPD技术就其浮游生物群落遗传多样性与物种多样性的关系进行了探索性研究.共鉴定出浮游生物41种,其中藻类4种,原生动物10种,轮虫类19种,枝角类4种,桡足类4种.物种组成相似性最高的是B站和C站,最低的是A站和F站.而站点间浮游生物群落遗传距离分析表明:相距最近的是C站与D站,最远的为D站与F站.树状聚类图也显示:各站点物种组成聚为一类;而DNA多态性RAPD最先聚在一起的是B与F,它们的对应枝由A、C、D、E构成,G单独成为一枝.研究表明,所发现的物种组成与所揭示的遗传多样性并未完全吻合.这或许是物种信息的缺失(如藻类与细菌),或许是RAPD技术的缺陷,或许两者所致.因此,本研究积累了三峡库区浮游生物群落遗传多样性的一些背景资料,而要阐释浮游生物群落遗传多样性与物种多样性之间的相互关系则有赖于应用灵敏的、重复性好的,且能分别分析原核和真核生物的DNA分子标记技术. 相似文献
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以天蓝喇叭虫(Stentor coeruleus)为研究对象,探索了单细胞单基因PCR扩增及单细胞全基因组PCR扩增技术在原生动物中的应用.经过不断探索和优化条件后,试验取得了理想的结果.在40例单细胞单基因(SSU rDNA基因全序列)PCR的一次性扩增中,新鲜细胞和经过中性红染色的细胞都获得了100%的成功率,室温下酒精(95%)保存一周的细胞获得了82.5%的成功率.在单细胞全基因组PCR扩增中,采用高效高保真的phi29 DNA聚合酶结合随机引物(Random Primer)进行扩增,获得了丰富且质量较高的PCR产物.以全基因组扩增产物(稀释10倍)对四个常用的基因位点(TEF1、SSU rRNA、18S-ITS1-5.8S、a-tubulin)进行扩增,均成功获得相应的基因片断. 相似文献
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牛山湖浮游生物群落DNA指纹结构与理化因子的关系 总被引：2，自引：0，他引：2
对牛山湖5个站点的浮游生物群落DNA多态性进行了RAPD指纹和PCR-DGGE指纹分析,并探讨了其与理化因子的关系.结果如下:1)从40条随机引物中筛选出9条引物,共获得93条谱带,多态率为58%;各站点所得谱带平均为67条,其中I站最少,为61条,V站最多,为74条;2)PCR-DGGE指纹图谱共含102条谱带,其中原核生物56条,真核生物46条,谱带总数以Ⅲ站、Ⅳ站和V站较多,Ⅰ站和Ⅱ站较少;3)Ⅱ站的总磷、叶绿素、化学耗氧量、硬度及电导率最高;各站点间溶氧和pH差异较小.相似性聚类分析表明,浮游生物群落DNA指纹将5个站点划分为两支,Ⅰ站和Ⅱ站聚为一支,Ⅲ站、Ⅳ站和V站聚为另一支,理化因子将Ⅰ站、Ⅲ站、Ⅳ站和V站聚为一支,Ⅱ站单独聚为一支.研究表明牛山湖浮游生物群落DNA指纹结构与理化因子具有一定的相关性,并且与环境主要限制因子总磷的含量是密切相关的.因此,浮游生物群落级水平DNA分析能简便、准确、迅速地反映水质状况,这方面资料的积累可以为建立一种基于分子生物学简便而灵敏的水环境评价体系提供科学依据. 相似文献
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鞭毛虫的扫描电镜样品制备 总被引：3，自引：0，他引：3
针对鞭毛虫样品制备中的难点，以Bodomorpha minima，Hollande 1942为材料，对一类个体微小的异养性鞭毛虫的扫描电镜样品的制备做了初步探讨。以载玻片为载体，0．1％的多聚赖氨酸为粘附剂，2％的戊二醛为固定剂，采用临界点法干燥，获得了较为满意的扫描电镜照片。该技术可简化样品制备步骤，减少样品损失，对于其他原生动物样品和游离细胞样品扫描电镜的制备也有积极的借鉴意义。 相似文献
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The spatial distribution pattern of organisms is a basic issue in understanding the mechanisms of community assembly. Although the spatial distributions of animals and plants have been well studied, those of microorganisms are still being debated. In this study, we used a fish gut microecosystem to detect the spatial pattern of microbes, because it can provide a relatively unified and stable environment. Results suggest that the turnover of intestinal bacterial assemblages showed a weak but highly significant negative correlation between similarity and distances in the microbial community, in respect of both grass carp intestinal loci distances and the geographical distance between fish sampling sites. Our results also suggest that intestinal bacterial assemblages responded to differences within the external environment and within different parts of the fish themselves. These results show that some, or possibly all, microbes are restricted in their distribution and that environmental factors are also important influences on the structure of intestinal bacterial assemblages. The fish gut microecosystem is useful in promoting study of the spatial distribution patterns of microorganisms. 相似文献
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2010年10月-2011年9月在太湖梅梁湾围隔内研究了改性当地土壤絮凝除藻及其对水质改善的应急和长期效果,并结合室内实验研究了该技术防控底泥再悬浮和减少底泥二次污染的长效机制.现场围隔实验结果表明,改性当地土壤除藻30 min后,TN、NO3--N、NH4+-N、TP、PO34--P和Chl.a的去除率分别为66%、57%、60%、93%、92%和98%;长期监测结果表明,与对照区域相比,围隔内的TN、NH4+-N、NO3--N、TP和PO34--P在处理后11个月内的平均值分别降低了39.83%、52.30%、48.53%、18.75%和60.00%.室内再悬浮实验结果表明,改性土壤和沙子抗再悬浮能力较未改性土壤分别提高了3和5倍.室内柱培养结果表明改性土壤絮凝除藻和沙土覆盖相结合可有效提高表层沉积物-水界面的氧化还原电位和溶解氧,使沉积物向水体的TP和TN通量从源逆转成汇,PO34--P和NH4+-N通量大幅度降低.改性土壤技术在利用絮凝除藻快速改善水质后,可通过改性沙/土分层底泥调控分别达到对藻絮体再悬浮的物理控制和营养盐再释放的化学控制,通过将亚表层底泥中的藻细胞分解并被沉水植物根系吸收,可实现对底泥中水华蓝藻复苏和水体富营养化的长效生态控制. 相似文献
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Bacterioplankton play key roles in the biogeochemical cycle and in organic contaminant degradation. The species richness and abundance of bacterial subgroups are generally distinct from each other, and this is attributed to their different functions in aquatic ecosystems. The spatiotemporal variations of eight phylogenetic subgroups （Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Planctomycetes, alpha-, beta-, and gamma-Proteobacteria） derived from Donghu Lake were investigated using PCR-DGGE fingerprinting, to explore their responses to environmental factors. Results indicate that Actinobacteria and beta-Proteobacteria were the two largest bacterial subgroups detected. These two groups and Bacteroidetes showed clear seasonal patterns in composition of the operational taxonomic unit. Results also suggest that the bacterioplankton subgroups in Donghu Lake were significantly correlated with different environmental factors. In brief, the total nitrogen was one of the major factors regulating all the bacterioplankton except for Actinobacteria. However, total phosphorus, another important eutrophication factor, contributed to the two largest bacterial groups （Actinobacteria and beta-Proteobacteria）, as well as to the Cyanobacteria and Firmicutes. Therefore, the responses of bacterioplankton subgroups to environmental factors were different, and this should be attributed to the differences in the fimctions of different groups. 相似文献
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转基因鱼试验湖浮游生物群落DNA多态性与物种组成关系 总被引：2，自引：0，他引：2
采用RAPD和PCR-DGGE指纹技术对转基因鱼试验湖的浮游生物群落DNA多态性进行了研究,并探讨了DNA多态性与物种组成的关系.结果显示:(1)形态学分类共鉴定到44种/类浮游生物:其中藻类13种,原生动物11种,轮虫16种,枝角类和桡足类各2种.多甲藻(Peridinium sp.)、球形砂壳虫(Difllugia globulosa)、螺形龟甲轮虫(Keratella cochlearis)和针簇多肢轮虫(Polyarthra trigla)4个物种在各个站丰度相对较高.(2)RAPD扩增共获得128条长度在200-1200bp的谱带,多态率为61.7%,特异性谱带占总谱带的19.5%.(3)PCR-DGGE指纹分析共获得87条扩增谱带,其中原核生物谱带相对较多(50条),真核生物谱带较少(37条),多态率分别为86%和64.9%.尽管形态学鉴定和DNA指纹分析都表现出较高物种多样性,但其相似性聚类却有差别:物种组成聚类中B、C站聚为一类,D、E站聚为一类,A站独为一类;两种DNA指纹分析聚类结果显示C、D、E三站聚为一类,A、B聚为一类.综上所述,在对浮游生物群落的研究中,形态学方法与DNA指纹技术不显著对应,后者能揭示更丰富的物种多样性,但毫无疑问三种方法可以从不同方面表征群落结构.这将为进一步研究湖泊浮游生物群落结构和功能关系奠定坚实的基础. 相似文献