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Fucoidan, a mixture of sulfated fucose-containing polysaccharides, was prepared from the algal bodies of Cladosiphon okamuranus (class Phaeophyceae, order Chordariales, family Chordariaceae) with a yield of 2.0% of the wet weight of the alga. To obtain enzymes that digest the fucoidan, we screened bacteria in the gut contents of the sea cucumber Stichopus japonicus for their ability to decrease the fucoidan in their culture media, and successfully isolated one bacterial strain that could decrease it. The bacterial strain was gram-negative and possessed menaquinone 7 as the predominant respiratory quinone, and the GC content of its genomic DNA was 52%. The results of the phylogenetic analysis of its 16S ribosomal DNA sequence indicated that the bacterial strain was a member of the division Verrucomicrobia. However, as the bacterial strain is phylogenetically and phenotypically distinct from verrucomicrobial species described previously, the strain was assumed to be a new member of the division Verrucomicrobia. When the bacterial strain was cultivated in an algal fucoidan-containing medium, the strain decreased fucoidan from C. okamuranus (44%), Nemacystus decipiens (19%), Laminaria japonica (31%), Kjellmaniella crassifolia (23%), sporophyl of Undaria pinnatifida (22%), Fucus vesiculosus (42%), and Ascophyllum nodosum (61%). 相似文献
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Environmental factors influencing the distribution of rRNA from Verrucomicrobia in soil 总被引:4,自引:0,他引:4
The Verrucomicrobia constitute a newly discovered division of the Bacteria identified as a numerically abundant component of soil microbial communities in numerous sites around the world. The relative abundance of rRNA from Verrucomicrobia was investigated in the soil to examine the influence of specific environmental factors on the distribution of Verrucomicrobia and to better understand the distribution of this group in terrestrial ecosystems. The abundance of the verrucomicrobial rRNA was determined by using a novel oligonucleotide probe that is specific for verrucomicrobial 16S rRNA. The abundance of verrucomicrobial 16S rRNA in soil microbial communities was determined in relation to plant community composition and soil management history over a period of 2 years. Additional samples were analyzed to determine if verrucomicrobial rRNA relative abundance changes in relation to either soil depth or soil moisture content. The Verrucomicrobia composed 1.9+/-0.2% of the microbial community rRNA present in the 85 soil samples examined. The distribution of verrucomicrobial rRNA in the soil reveals that Verrucomicrobia are significantly affected by environmental characteristics that change in relation to time, soil history, and soil depth, and reveals that a statistically significant amount of the variation in verrucomicrobial rRNA abundance can be explained by changes in soil moisture content. 相似文献
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Ulisses Nunes da Rocha Leo van Overbeek & Jan Dirk van Elsas 《FEMS microbiology ecology》2009,69(3):313-328
The rhizosphere environment selects a particular microbial community that arises from the one present in bulk soil due to the release of particular compounds in exudates and different opportunities for microbial colonization. During plant–microorganism coevolution, microbial functions supporting plant health and productivity have developed, of which most are described in cultured plant-associated bacteria. This review discusses the state of the art concerning the ecology of the hitherto-uncultured bacteria of the rhizosphere environment, focusing on Acidobacteria, Verrucomicrobia and Planctomycetes . Furthermore, a strategy is proposed to recover bacterial isolates from these taxa from the rhizosphere environment. 相似文献
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Anna Kielak Jorge L.M. Rodrigues Eiko E. Kuramae Patrick S.G. Chain Johannes A. van Veen & George A. Kowalchuk 《FEMS microbiology ecology》2010,71(1):23-33
The bacterial phylum Verrucomicrobia has a widespread distribution, and is known to be one of the most common and diverse phyla in soil habitats. However, members of this phylum have typically been recalcitrant to cultivation methods, hampering the study of this presumably important bacterial group. In this study, we examine the phylogenetic diversity of the Verrucomicrobia in a former agricultural field and gain access to genomic information via a metagenomic approach. We examined Verrucomicrobia -like 16S rRNA gene sequences recovered from general bacterial and phylum-specific libraries, revealing a dominance of subdivisions 1 and 2. A PCR-based screening method was developed to identify inserts containing verrucomicrobial 16S rRNA genes within a large-insert metagenomic library, and on screening of 28 800 clones, four fosmids were identified as containing verrucomicrobial genomic DNA. Full-length sequencing of fosmid inserts and gene annotation identified a total of 98 ORFs, representing a range of functions. No conservation of gene order was observed adjacent to the ribosomal operons. Fosmid inserts were further analyzed for tetranucleotide frequencies to identify remnants of past horizontal gene transfer events. The metagenomic approach utilized proved to be suitable for the recovery of verrucomicrobial genomic DNA, thereby providing a window into the genomes of members of this important, yet poorly characterized, bacterial phylum. 相似文献
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腹泻是制约梅花鹿(Cervus nippon)养殖发展的主要因素之一,通常与肠道菌群失衡有关,而健康与腹泻梅花鹿个体菌群组成变化尚不清楚。为探究健康与腹泻梅花鹿肠道菌群差异,分析梅花鹿腹泻原因,以圈养雄性梅花鹿为实验对象,采集正常及腹泻梅花鹿粪便共18份,通过16S rRNA基因测序进行比较分析。研究结果表明,腹泻组菌群丰度及多样性较健康组均有所下降。在门至属水平,腹泻组理研菌科(Rikenellaceae)、克里斯滕森菌科(Christensenellaceae)等有益菌丰度下降,Treponema_2菌属等促炎菌丰度上升。此外,瘤胃球菌科UCG-014菌属(Ruminococcaceae_UCG-014)和理研菌科RC9菌属(Rikenellaceae_RC9_gut_group)在健康组中显著富集;疣微菌门(Verrucomicrobia)、拟普雷沃氏菌属(Alloprevotella)、阿克曼氏菌属(Akkermansia)在腹泻组显著富集。腹泻梅花鹿与健康梅花鹿粪便菌群组成和多样性存在显著差异,疣微菌门丰度升高可能是导致梅花鹿腹泻的一个原因。 相似文献
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