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1.
综合养殖池塘中三角帆蚌和鱼类肠道细菌的组成   总被引:1,自引:0,他引:1  
采用 PCR-DGGE (PCR-denaturing gradient gel electrophoresis)方法研究了综合养殖池塘中三角帆蚌(Hyriopsis cumingii)、草鱼(Ctenopharyngodon idella)、鳊(Parabramis pekinensis)、银鲫(Carassius auratus gibelio)、青鱼(Mylopharyngodon piceus)和鳙(Aristichthys nobilis)的肠道细菌组成,并分析了水体中的浮游细菌对鱼、蚌肠道细菌的影响。研究结果表明,三角帆蚌和混养鱼类肠道细菌属于厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、疣微菌门(Verrucomicrobia)、蓝细菌(Cyanobacteria)、梭杆菌门(Fusobacteria)。其中,三角帆蚌肠道优势菌群为不动杆菌属(Acinetobacter)、志贺氏菌属(Shigella)和分枝杆菌属(Mycobacterium),草鱼肠道优势菌群为梭菌属(Clostridium),鳊肠道优势菌群为梭菌属和假单胞菌属(Pseudomonas),银鲫肠道优势菌群为不动杆菌属和志贺氏菌属,青鱼肠道优势菌群为梭菌属和不动杆菌属,鳙肠道优势菌群为不动杆菌属和弧菌属(Vibrio)。三角帆蚌与银鲫肠道细菌谱带相似性较高,草鱼与鳊肠道细菌谱带相似性较高,表明鱼类肠道细菌组成特点与食性存在一定的关系。水体浮游细菌优势菌群为类芽孢杆菌属(Paenibacillus)。三角帆蚌及鱼类肠道细菌群落与水体浮游细菌群落组成相似性较低,表明水体浮游细菌对三角帆蚌和鱼类肠道细菌优势菌群的影响有限。  相似文献   

2.
采用16S rRNA高通量测序,系统研究了光唇鱼(Acrossocheilus fasciatus)仔鱼、稚鱼和幼鱼肠道菌群组成及与同时期养殖水体细菌群落的相关性。研究结果表明,光唇鱼仔鱼、稚鱼和幼鱼的肠道菌群中Chao1指数和Shannon指数均没有显著变化(P>0.05);而随着光唇鱼幼体的发育,养殖水体中Chao1指数和Shannon指数呈现显著下降趋势(P<0.05)。光唇鱼仔鱼和稚鱼肠道菌群中的优势菌门由变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)组成,而同时期养殖水体中优势菌门为变形菌门;光唇鱼幼鱼肠道菌群中的优势菌门为梭杆菌门(Fusobacteria)和变形菌门,同时期养殖水体中优势菌门由变形菌门、拟杆菌门和梭杆菌门组成。线性回归分析结果显示,随光唇鱼幼体发育,在光唇鱼肠道菌群中变形菌门、厚壁菌门和梭杆菌门相对丰度的时序变化趋势与其在养殖水体中相同。在属水平上,光唇鱼仔鱼、稚鱼肠道菌群中优势菌属均为醋酸杆菌属(Acetobacter),而幼鱼肠道菌群中优势菌属为鲸杆菌属(Cetobacte...  相似文献   

3.
野生动物的肠道微生物组成受食物资源和遗传属性的影响较大, 为了解北京地区小型猫科动物肠道菌群组成特点及其影响因素, 本研究通过扩增细菌16S rRNA的V3‒V4高变区进行高通量测序, 对云蒙山、云峰山、松山、百花山4个区域的豹猫(Prionailurus bengalensis)亚种群进行肠道菌群组成分析。结果表明, 在门水平上, 豹猫的肠道优势菌群主要由厚壁菌门(相对多度52.40%)、变形菌门(25.18%)、放线菌门(9.07%)、拟杆菌门(8.17%)和梭杆菌门(4.74%)组成。在属水平上, 相对多度最高的前5个属为假单胞菌属(Pseudomonas, 13.37%)、布劳特氏菌属(Blautia, 11.20%)、梭菌属(Clostridium_sensu_stricto_1, 9.10%)、消化梭菌属(Peptoclostridium, 8.62%)、乳杆菌属(Lactobacillus, 6.08%), 共约占总多度的50%。各区域豹猫亚种群的肠道菌群β多样性不存在显著差异, 松山区域的ACE指数和Chao 1指数与云蒙山和云峰山存在显著差异。鉴于松山亚种群的遗传结构与其他区域有所不同, 而4个区域的气候类型和豹猫食物构成相似性高, 推测该亚种群的肠道菌群主要受遗传结构分化的影响, 对此还需进一步研究。  相似文献   

4.
目的通过检测干燥综合征(Sj9gren′s syndrome,SS)患者粪便标本的微生物种群分布及外周血Treg细胞绝对计数,分析SS患者肠道菌群变化状态及其与Treg细胞的相关性,为临床诊疗提供新思路。方法通过采用Illumina HiSeq 2500高通量测序平台对29例干燥综合征患者粪便标本中的16S rRNA V3区进行定性分析,与83例健康人粪便标本中菌群的多样性与丰富度统计数据进行比较,分析SS患者中差异性菌群丰富度及其与Treg细胞绝对计数的关系。结果两组研究对象性别、年龄比较差异均无统计学意义(P0.05)。与健康人对比,SS患者粪便菌群中细菌多样性低于健康对照组(P0.05),肠道菌群丰富度在门(Phylum)水平上厚壁菌门(Firmicutes)细菌数量较正常对照组减少(P0.05),变形菌门(Proteobacteria)和放线菌门(Actinobacteria)较健康对照组明显增加(均P0.05)。在科(Family)水平上链球菌科(Streptococcaceae)、肠杆菌科(Enterobacteriales)和乳杆菌科(Lactobacillaceae)细菌数量较正常对照组明显升高(均P0.05),普雷沃菌科(Prevotellaceae)和Paraprevotellaceae较对照组明显减少(均P0.05)。在属(Genus)水平上Blautia、颤螺旋菌属(Oscillospira)、链球菌属(Streptococcus)和韦荣球菌属(Veillonella)细菌数量较正常对照组明显升高(均P0.05),而Roseburia、粪杆菌属(Faecalibacterium)和普氏菌属(Prevotella)较正常对照组明显减少(均P0.05)。其中,SS患者粪便中韦荣球菌属的百分比与其外周血Treg细胞绝对计数呈显著负相关(P0.05)。结论 SS患者肠道微生态环境中细菌群落的多样性和均衡性与正常人群存在明显差异,且韦荣球菌属水平的升高与外周血Treg细胞绝对计数呈显著负相关,肠道菌群紊乱或许参与了SS的发病过程。  相似文献   

5.
【目的】为研究137Cs辐照前后橘小实蝇雄虫肠道菌群多样性和丰度的变化及其肠道菌群在不同分类阶元上的显著差异物种。【方法】本研究利用IlluminaHiSeq高通量测序技术对辐照组和对照组共6个样品进行测序分析。【结果】变形菌门和厚壁菌门分别以60.38%、24.33%的比例作为橘小实蝇肠道中的优势菌门和次优势菌门,肠杆菌科和肠球菌科分别以60.38%和15.69%作为优势菌科和次优势菌科。米勒氏菌属(Moellerella)、摩根氏菌属(Morganella)、Cosenzaea属、链球菌科未知属和酸热菌属(Acidothermus)是组间显著差异的菌属。【结论】本研究发现橘小实蝇在辐照后的肠道菌群多样性和丰度均有显著性降低,并在目至属等3个分类阶元上找到辐照后具有显著差异的物种,为后期利用差异菌群来改善辐照对橘小实蝇的消极影响及修复辐照损伤提供理论基础。  相似文献   

6.
目的为了解湿疹患儿肠道菌群的结构与湿疹之间的关系,通过对湿疹患儿和健康儿童粪便样本细菌总DNA提取,利用高通量测序技术,比较健康儿童和湿疹患儿肠道菌群的异同。方法 10例年龄在2个月~2岁婴幼儿由皮肤科门诊确诊为湿疹伴有过敏性疾病家族史作为研究对象,年龄和性别相当健康儿童10例作为对照,分别收集其粪便标本并提取所有样本中细菌的总DNA,对16SrRNA基因进行高通量测序,获得两组的肠道菌群结构数据并进行菌群差异性分析。结果通过Roche 454高通量测序,两组肠道微生物菌群多样性指数比较差异无统计学意义。两组主要由Firmicutes(厚壁菌门)、Bacteroidetes(拟杆菌门)、Proteobacteria(变形菌门)和Actinobacteria(放线菌门)4个门组成;两组在门水平上进行菌群结构比较,差异无统计学意义。两组样本在属水平上共获得200个不同属的细菌,其中Bacillus(芽孢杆菌属)、Bilophila(噬胆菌属)、Christensenella(纺锤状细菌属)、Coprobacillus、Eikenella(艾肯菌属)、Enterobacter(肠杆菌属)、Eubacterium(真杆菌属)、Lactococcus(乳球菌属)、Megamonas(巨单胞菌属)、Leuconostoc(明串珠菌属)、Morganella(摩根菌属)、Rhizobacter(根杆菌属)、Proteus(变形菌属)、Sutterella(萨特菌属)、Veillonella(韦荣球菌属)、Akkermansia、Anaeroglobus、Anaerotruncus、Butyricicoccus、Epulopiscium、Gordonibacter、Lachnospiraceae uncultured、Robinsoniella和Varibaculum共24个属在两组间差异具有统计学意义。结论湿疹患儿肠道菌群与健康儿童相比,菌群多样性指数(Shannon指数和Simpson指数)未见明显差异,但在菌群结构上发生了一些变化,某些特别的细菌菌属存在显著性差异。  相似文献   

7.
肠道菌群在维持宿主免疫和消化系统功能方面发挥着重要作用,肠道菌群的多样性和丰富度是衡量宿主健康状况的重要生理指标。性激素对动物生长发育发挥重要作用,但其对肠道菌群构成影响的相关实验研究相对较少。本研究以模式生物小鼠(Mus musculus)为对象,探究性激素的变化对小鼠肠道菌群构成的影响。采用外科手术方式建立小鼠去势模型,通过16S r RNA高通量测序技术,研究性激素对小鼠肠道菌群构成的影响。研究结果表明,雌性小鼠和雄性小鼠去势后,性激素水平显著下降。肠道菌群在门水平上,正常小鼠和去势小鼠肠道细菌群落均由拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、埃普西隆杆菌门(Epsilonbacteraeota)、髌骨细菌门(Patescibacteria)、放线菌门(Actinobacteria)、软壁菌门(Tenericutes)、脱铁杆菌门(Deferribacteres)、酸杆菌门(Acidobacteria)和蓝藻细菌门(Cyanobacteria)组成,主要菌群为厚壁菌门和拟杆菌门物种,两门占物种相对丰度百分比...  相似文献   

8.
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   

9.
淡水螺是水生态系统中重要的生物类群,也是多种寄生虫的中间宿主。肠道菌群在动物能量代谢和抵抗病原体方面起着重要作用。本文分析了耳萝卜螺Radix auricularia和三旋卷丽螺Planorbella trivolvis肠道菌群的多样性。结果表明:在门水平上,耳萝卜螺有23个菌门,以变形菌门 (Proteobacteria,33.63%)、蓝细菌门(Cyanobateria,15.33%)、绿弯菌门 (Chloroflexi,13.95%) 和放线菌门 (Actinobacteria,12.99%)为主;三旋卷丽螺有13个菌门,以变形菌门 (54.88%)、拟杆菌门 (Bacteroidetes,28.49%) 和放线菌门 (7.65%) 为主。属水平上,耳萝卜螺有厚皮藻属Pleurocapsa、硫网菌属Thiodictyon、纤毛菌属Leptotrichia及类诺卡氏菌属Nocardioides等445个属;三旋卷丽螺有Cloacibacterium、OM60NOR5_clade、假单胞菌属Pseudomonas及红杆菌属Rhodobacter等238个属。有93个菌属为两种螺的共有核心菌群 (所有样本中都存在),其中27个菌属丰度大于0.5%。两种螺肠道菌群结构差异显著 (P=0.027)。PICRUSt功能预测分析表明,两种螺肠道菌群KEGG功能组成相似,氨基酸代谢、碳水化合物代谢及膜转运丰度较大。综上,两种草食性淡水螺肠道菌群多样性较高且差异显著,但有数量较多的共有核心菌群。  相似文献   

10.
美洲大蠊Periplaneta americana既是卫生害虫,也是重要的药用昆虫。许多研究表明,其肠道菌群种类和数量与宿主健康密切相关。本实验利用16S r RNA高通量测序技术分析了人工饲养的美洲大蠊成虫肠道菌群。结果得到有效序列67 492条,归类为581个操作分类单元,注释到21门79目193属。厚壁菌门Firmicutes(56.96%)和拟杆菌门Bacteroidetes(33.13%)为美洲大蠊成虫肠道的优势菌门。葡萄球菌属Staphylococcus(16.59%)、芽孢杆菌属Bacillus(13.26%)和副杆菌属Parabacteroides(10.26%)为美洲大蠊成虫肠道的优势菌属。研究结果为进一步探讨美洲大蠊肠道菌群多样性以及与宿主之间的关系打下了基础。  相似文献   

11.
肠道微生物组被誉为动物的“第二套基因组”,与动物的个体发育、营养获取、生理功能、免疫调节等重要活动密切相关。非人灵长类在生态位、社会结构、地理分布以及进化上与人类相近,开展其肠道微生物研究不仅有助于了解灵长类的生态、保护和进化,而且对深入了解肠道微生物在人类进化中所发挥的作用也具有重要的参考价值。本文总结了影响非人灵长类肠道微生物变化的因素,包括系统发育、觅食、栖息地破碎化、年龄和性别、圈养方式以及社群生活,并探讨了肠道微生物研究在非人灵长类生态、行为、保护以及适应性进化方面的应用。未来,非人灵长类肠道微生物研究将为灵长类生态、进化和人类健康的研究提供新的视角,为灵长类的保护提供新的理论基础和研究方法。  相似文献   

12.
Changes in agricultural land-use of saltmarshes along the German North Sea coast have favoured the succession of the marsh grass Elytrigia atherica over the long-established Spartina anglica. Consequently, E. atherica represents a potential food source of increasing importance for plant-feeding soil detritivores. Considering the importance of this ecological guild for decomposition processes and nutrient cycling, we focussed on two sympatric saltmarsh soil macrodetritivores and their associated gut microbiota to investigate how the digestive processes of these species may be affected by changing plant food sources. Using genetic fingerprints of partial 16S rRNA gene sequences, we analysed composition and diversity of the bacterial gut community in a diplopod and an amphipod crustacean in relation to different feeding regimes representing the natural vegetation changes. Effects of syntopy on the host-specific gut microbiota were also taken into account by feeding the two detritivore species either independently or on the same plant sample. Bacterial community composition was influenced by both the host species and the available plant food sources, but the latter had a stronger effect on microbial community structure. Furthermore, bacterial diversity was highest after feeding on a mixture of both plant species, regardless of the host species. The gut microbiota of these two detritivores can thus be expected to change along with the on-going succession at the plant community level in this environment. Cloning and sequencing of bacterial 16S rRNA gene fragments further indicated a host-related effect since the two detritivores differed in terms of predominant bacterial taxa: diplopods harboured mainly representatives of the phyla Bacteroidetes and Gammaproteobacteria. In contrast, the genus Vibrio was found for the amphipod host across all feeding conditions.  相似文献   

13.
After birth, mammals acquire a community of bacteria in their gastro-intestinal tract, which harvests energy and provides nutrients for the host. Comparative studies of numerous terrestrial mammal hosts have identified host phylogeny, diet and gut morphology as primary drivers of the gut bacterial community composition. To date, marine mammals have been excluded from these comparative studies, yet they represent distinct examples of evolutionary history, diet and lifestyle traits. To provide an updated understanding of the gut bacterial community of mammals, we compared bacterial 16S rRNA gene sequence data generated from faecal material of 151 marine and terrestrial mammal hosts. This included 42 hosts from a marine habitat. When compared to terrestrial mammals, marine mammals clustered separately and displayed a significantly greater average relative abundance of the phylum Fusobacteria. The marine carnivores (Antarctic and Arctic seals) and the marine herbivore (dugong) possessed significantly richer gut bacterial community than terrestrial carnivores and terrestrial herbivores, respectively. This suggests that evolutionary history and dietary items specific to the marine environment may have resulted in a gut bacterial community distinct to that identified in terrestrial mammals. Finally we hypothesize that reduced marine trophic webs, whereby marine carnivores (and herbivores) feed directly on lower trophic levels, may expose this group to high levels of secondary metabolites and influence gut microbial community richness.  相似文献   

14.
The human colonic microbiota degrades dietary substrates that are indigestible in the upper GIT (gastrointestinal tract), releasing bacterial metabolites, some of which are important for gut health. Advances in molecular biology techniques have facilitated detailed analyses of the composition of the bacterial community resident in the lower GIT. Such analyses have indicated that more than 500 different bacterial species colonize an individual, and that, although there is much functional consistency in the resident bacterial groups, there is considerable inter-individual variation at the species/strain level. The bacterial community develops during early childhood until it reaches an adult-like composition. Whereas colonization and host factors influence the species composition, dietary factors also have an important impact, with specific bacterial groups changing in response to specific dietary interventions. Since bacterial species have different metabolic activities, specific diets have various consequences for health, dependent on the effect exerted on the bacterial population.  相似文献   

15.
Many insects contain diverse gut microbial communities. While several studies have focused on a single or small group of species, comparative studies of phylogenetically diverse hosts can illuminate general patterns of host–microbiota associations. In this study, we tested the hypotheses that (i) host diet and (ii) host taxonomy structure intestinal bacterial community composition among insects. We used published 16S rRNA gene sequence data for 58 insect species in addition to four beetle species sampled from the Sevilleta National Wildlife Refuge to test these hypotheses. Overall, gut bacterial species richness in these insects was low. Decaying wood xylophagous insects harboured the richest bacterial gut flora (102.8 species level operational taxonomic units (OTUs)/sample ± 71.7, 11.8 ± 5.9 phylogenetic diversity (PD)/sample), while bees and wasps harboured the least rich bacterial communities (11.0 species level OTUs/sample ± 5.4, 2.6 ± 0.8 PD/sample). We found evidence to support our hypotheses that host diet and taxonomy structure insect gut bacterial communities (P < 0.001 for both). However, while host taxonomy was important in hymenopteran and termite gut community structure, diet was an important community structuring factor particularly for insect hosts that ingest lignocellulose‐derived substances. Our analysis provides a baseline comparison of insect gut bacterial communities from which to test further hypotheses concerning proximate and ultimate causes of these associations.  相似文献   

16.
The gut microorganisms in some animals are reported to include a core microbiota of consistently associated bacteria that is ecologically distinctive and may have coevolved with the host. The core microbiota is promoted by positive interactions among bacteria, favoring shared persistence; its retention over evolutionary timescales is evident as congruence between host phylogeny and bacterial community composition. This study applied multiple analyses to investigate variation in the composition of gut microbiota in drosophilid flies. First, the prevalence of five previously described gut bacteria (Acetobacter and Lactobacillus species) in individual flies of 21 strains (10 Drosophila species) were determined. Most bacteria were not present in all individuals of most strains, and bacterial species pairs co-occurred in individual flies less frequently than predicted by chance, contrary to expectations of a core microbiota. A complementary pyrosequencing analysis of 16S rRNA gene amplicons from the gut microbiota of 11 Drosophila species identified 209 bacterial operational taxonomic units (OTUs), with near-saturating sampling of sequences, but none of the OTUs was common to all host species. Furthermore, in both of two independent sets of Drosophila species, the gut bacterial community composition was not congruent with host phylogeny. The final analysis identified no common OTUs across three wild and four laboratory samples of D. melanogaster. Our results yielded no consistent evidence for a core microbiota in Drosophila. We conclude that the taxonomic composition of gut microbiota varies widely within and among Drosophila populations and species. This is reminiscent of the patterns of bacterial composition in guts of some other animals, including humans.  相似文献   

17.
赵帅  周娜  赵振勇  张科  吴国华  田长彦 《微生物学报》2016,56(10):1583-1594
【目的】揭示同一盐渍环境中不同种盐生植物根部内生细菌群落多样性特征和分布规律,结合根际土壤理化因子探讨其对内生细菌群落结构的影响。【方法】通过罗氏454高通量测序获得内生细菌16S r RNA片段,然后进行生物信息分析。【结果】研究的16种盐生植物其内生细菌群落主要由Proteobacteria、Tenericutes、Actinobacteria和Firmicutes 4个门的细菌组成。从植物"种"的水平来看,不同种盐生植物内生细菌群落存在差异;从植物"属"的水平来看,同一属的盐生植物内生细菌相似;从植物"科"的水平来看,藜科盐生植物内生细菌以Actinobacteria和Proteobacteria门为主;蒺藜科盐生植物内生细菌以Proteobacteria门为主;柽柳科盐生植物内生细菌以Tenericutes门为主;白花丹科盐生植物内生细菌以Proteobacteria、Fimicutes和Actinobacteria门为主。根际土壤中Cl~–含量对盐生植物内生细菌群落变化具有显著影响;而Cl~–、Mg~(2+)和总氮组成的集合与内生细菌群落结构相关性最高。【结论】盐生植物内生细菌多样性丰富。在同一盐渍生境中,盐生植物内生细菌群落分布呈现宿主的种属特异性,根际土壤中Cl~–是影响其内生细菌群落变化的主要驱动因素之一。  相似文献   

18.

Background

The human gastrointestinal tract is inhabited by a very diverse symbiotic microbiota, the composition of which depends on host genetics and the environment. Several studies suggested that the host genetics may influence the composition of gut microbiota but no genes involved in host control were proposed. We investigated the effects of the wild type and mutated alleles of the gene, which encodes the protein called pyrin, one of the regulators of innate immunity, on the composition of gut commensal bacteria. Mutations in MEFV lead to the autoinflammatory disorder, familial Mediterranean fever (FMF, MIM249100), which is characterized by recurrent self-resolving attacks of fever and polyserositis, with no clinical signs of disease in remission.

Methodology/Principal Findings

A total of 19 FMF patients and eight healthy individuals were genotyped for mutations in the MEFV gene and gut bacterial diversity was assessed by sequencing 16S rRNA gene libraries and FISH analysis. These analyses demonstrated significant changes in bacterial community structure in FMF characterized by depletion of total numbers of bacteria, loss of diversity, and major shifts in bacterial populations within the Bacteroidetes, Firmicutes and Proteobacteria phyla in attack. In remission with no clinical signs of disease, bacterial diversity values were comparable with control but still, the bacterial composition was substantially deviant from the norm. Discriminant function analyses of gut bacterial diversity revealed highly specific, well-separated and distinct grouping, which depended on the allele carrier status of the host.

Conclusions/Significance

This is the first report that clearly establishes the link between the host genotype and the corresponding shifts in the gut microbiota (the latter confirmed by two independent techniques). It suggests that the host genetics is a key factor in host-microbe interaction determining a specific profile of commensal microbiota in the human gut.  相似文献   

19.
The mammalian gastrointestinal tract harbors a diverse and complex resident bacterial community, which interacts with the host in many beneficial processes required for optimal host health. We are studying the importance of bacterial cell-cell communication mediated by the interspecies quorum-sensing signal autoinducer-2 (AI-2) in the beneficial properties of the gut microbiota. Our recent work provided the first evidence that AI-2 produced by Escherichia coli can influence the species composition of this community in the mouse gut. We showed that, under conditions of microbiota imbalances induced by antibiotic treatments, E. coli, which increases intestinal AI-2 levels, not only had an effect on the overall structure of the microbiota community, but specifically favored the expansion of the Firmicutes phylum. Because the Firmicutes are very important for many gut functions and were the group of bacteria most severely affected by antibiotic treatment with streptomycin, we are addressing the possibility that AI-2 can influence the balance of the major bacterial groups in the gut and promote recovery of gut homeostasis. Overall, we want to understand how bacterial chemical signaling shapes the multi-species bacterial communities in the mammalian gut and how these communities affect host physiology.  相似文献   

20.
The gut microbiota of mammals underpins the metabolic capacity and health of the host. Our understanding of what influences the composition of this community has been limited primarily to evidence from captive and terrestrial mammals. Therefore, the gut microbiota of southern elephant seals, Mirounga leonina, and leopard seals, Hydrurga leptonyx, inhabiting Antarctica were compared with captive leopard seals. Each seal exhibited a gut microbiota dominated by four phyla: Firmicutes (41.5 ± 4.0%), Fusobacteria (25.6 ± 3.9%), Proteobacteria (17.0 ± 3.2%) and Bacteroidetes (14.1 ± 1.7%). Species, age, sex and captivity were strong drivers of the composition of the gut microbiota, which can be attributed to differences in diet, gut length and physiology and social interactions. Differences in particular prey items consumed by seal species could contribute to the observed differences in the gut microbiota. The longer gut of the southern elephant seal provides a habitat reduced in available oxygen and more suitable to members of the phyla Bacteroidetes compared with other hosts. Among wild seals, 16 ‘core’ bacterial community members were present in the gut of at least 50% of individuals. As identified between southern elephant seal mother–pup pairs, ‘core’ members are passed on via vertical transmission from a young age and persist through to adulthood. Our study suggests that these hosts have co‐evolved with their gut microbiota and core members may provide some benefit to the host, such as developing the immune system. Further evidence of their strong evolutionary history is provided with the presence of 18 shared ‘core’ members in the gut microbiota of related seals living in the Arctic. The influence of diet and other factors, particularly in captivity, influences the composition of the community considerably. This study suggests that the gut microbiota has co‐evolved with wild mammals as is evident in the shared presence of ‘core’ members.  相似文献   

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