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研究以草鱼(Ctenopharyngodon idellus)为实验对象, 运用厌氧培养的方法, 研究了饥饿状态下草鱼肠道黏膜固有微生物的类群及其在不同肠段的分布。实验结果显示草鱼前肠、中肠与后肠中细菌的数量分别是3.17×103、1.63×104和1.79×107 cfu/g。研究共分离到274株单菌落, 经16S rRNA鉴定, 分别属于拟杆菌属(Bacteroides spp.)、鲸杆菌属(Cetobacterium spp.)、梭形杆菌属(Fusobacterium spp.)、气单胞菌属(Aeromonas spp.)、希瓦氏菌属(Shewanella spp.)、芽孢杆菌属(Bacillus spp.)、泛菌属(Pantoea spp.)和柠檬酸杆菌属(Citrobacter spp.)8个种类, 其中专性厌氧细菌的数量占9.1%, 兼性厌氧细菌的数量占90.9%。进一步分析发现, 前肠中只分离到兼性厌氧细菌, 中肠与后肠专性厌氧细菌和兼性厌氧细菌都有分布。专性厌氧细菌Bacteroides paurosaccharolyticus和Bacteroides luti在中肠与后肠都有分布, 而Cetobacterium somerae和Fusobacterium ulcerans只在后肠有发现。兼性厌氧细菌是草鱼肠道黏膜的优势菌群, 其中嗜水气单胞菌Aeromonas hydrophila占73.7%。草鱼肠道不同部位固有厌氧微生物组成存在差异, 细菌数量也明显不同, 后肠中具有更高的细菌丰度和多样性。 相似文献
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厌氧微生物研究的新进展 总被引:4,自引:0,他引:4
厌氧微生物研究的新进展凌代文(中国科学院微生物研究所,北京100080)厌氧微生物是整个微生物世界的一个重要组成部分。厌氧微生物绝大多数为细菌,很少数是放线菌,极少数是枝原体,厌氧真菌尚见于个别的报道。厌氧微生物在自然界分布广泛。人类生活的环境和人体... 相似文献
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【背景】厌氧氨氧化过程是氮素循环过程的重要途径之一,在氮素循环中发挥重要作用。先前的研究已经证实了厌氧氨氧化细菌存在于多种生境中,但对其多样性分布还没有系统的研究。【目的】对厌氧氨氧化细菌在不同类型生境中的多样性分布规律进行深入分析,充分展示其在不同生境中的群落结构特点,并揭示多样性分布与环境因素之间的关系。【方法】在建立厌氧氨氧化细菌16S rRNA基因序列数据库的基础上,运用高通量测序技术分析其在不同生境中的多样性分布特征。【结果】厌氧氨氧化细菌在红树林、海湾和河口生境中的多样性水平较高,而污泥和红壤的多样性水平明显较低。系统发育分析表明,这些生境中的厌氧氨氧化细菌主要由Candidatus Brocadia、Ca.Scalindua和未明确分类地位的菌属组成;从河流到红树林生态系统,随着盐度的增加,厌氧氨氧化细菌的优势种属由Ca. Brocadia转变到Ca. Scalindua,相关性分析也表明了盐度是导致不同生境中厌氧氨氧化细菌群落结构差异的主要因素。【结论】不同生境中存在不同的厌氧氨氧化细菌种群结构,环境条件的差异影响了厌氧氨氧化细菌的种群分布和系统演化。 相似文献
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海洋厌氧氨氧化细菌分子生态学研究进展 总被引:4,自引:0,他引:4
厌氧氨氧化细菌是能在厌氧的条件下将氨氧化为氮气的一类细菌,这类细菌执行着以前未被人们所认知的一个独特的过程--氧氨氧化过程,据估计厌氧氨氧化过程对于海洋氮气的形成有30%~50%的贡献率;海洋厌氧氨氧化细菌能与氨氧化细菌及氨氧化古菌存在潜在的耦合作用,对于海洋氮循环复杂机制的阐述有着非常重要的意义;同时海洋厌氧氨氧化细菌独特的细胞和基因组结构,也成为了解海洋细菌进化重要的模式微生物之一.本文综述了近年来国内外厌氧氨氧化细菌分子生态学方面的进展,并结合作者的工作对未来的研究进行展望. 相似文献
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减毒鼠伤寒沙门菌由于具有肿瘤靶向性,能在肿瘤组织中复制并产生抗肿瘤效果的能力,使肿瘤治疗获得了新契机。减毒鼠伤寒沙门菌作为细菌载体使目的基因在肿瘤组织内特异表达,表现出良好治疗效果。近期研究发现,单独使用突变后的菌株A1-R在裸鼠模型上治疗乳腺癌和前列腺癌分别可达到40%和50%的治愈率;在小鼠肿瘤转移模型中也展现出良好的治疗效果。鼠伤寒沙门菌作为肿瘤治疗制剂有诱人的前景。本文就这些研究的最新进展做一综述。 相似文献
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提高抗肿瘤药物的靶向性是肿瘤治疗、降低药物副作用的重要手段。在肿瘤组织内部由于癌细胞的快速增殖致使其形成低氧区,低氧区会对多种肿瘤治疗方案产生耐受。趋磁细菌 (Magnetotactic bacteria, MTB) 是一类能在细胞内产生外包生物膜、纳米尺寸、单磁畴磁铁矿 (Fe3O4) 或硫铁矿 (Fe3S4) 晶体颗粒-磁小体的微生物的统称。在磁场的作用下,趋磁细菌可凭借鞭毛运动至厌氧区。趋磁细菌在动物体内毒性较低且生物相容性良好,其磁小体与人工合成的磁性纳米材料相比优势显著。文中在介绍趋磁细菌及其磁小体生物学特点、理化性能的基础上,综述了趋磁细菌作为载体偶联药物进入肿瘤内部,并通过感受低氧信号定位于肿瘤低氧区,以及趋磁细菌竞争肿瘤细胞铁源的研究进展,总结了磁小体运载化疗药物、抗体、DNA疫苗靶向结合肿瘤的研究进展,分析了趋磁细菌及磁小体肿瘤治疗中面临的问题,并对趋磁细菌和磁小体在肿瘤治疗中的应用进行了展望。 相似文献
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肿瘤是机体在各种致瘤因子作用下,局部组织细胞异常增生所形成的赘生物。肿瘤治疗一直是临床上的一个难题,而放疗、化疗和手术等常规的肿瘤治疗方法均具有明显的局限性。早期研究发现某些厌氧菌或兼性厌氧菌具有抗肿瘤效应,例如兼性厌氧菌鼠伤寒沙门氏菌可以通过某些机制选择性定殖于肿瘤并抑制肿瘤生长,其应用于肿瘤治疗具有许多潜在的优势。过去的一二十年里,已有不少研究者通过遗传操作减弱沙门菌毒力,提高其定殖肿瘤的靶向性,或以减毒沙门菌作为载体向肿瘤靶向递呈各种治疗分子,并在许多动物试验中观察到遗传改造沙门菌的良好抗肿瘤效应。随着沙门菌抗肿瘤研究的不断深入,应用遗传改造的沙门菌有希望成为一条更有效的肿瘤治疗途径。本文将从沙门菌的抗肿瘤机制、遗传改造的沙门菌介导肿瘤治疗的研究进展和目前研究存在的问题等方面进行综述。 相似文献
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胃癌及癌旁组织中无芽孢厌氧菌相关性的研究 总被引:1,自引:1,他引:0
在实验研究过程中发现 ,不同的消化道疾病患者 ,胃黏膜微生物群的检出率、菌种、数量均有不同 ,其中胃癌组微生物群改变最明显。为了解微生物与胃癌的相关性 ,对 5 7例胃癌患者的癌组织和癌旁组织进行了无芽孢厌氧菌的检测 ,实验结果表明 ,胃癌病变的中心部位与癌旁组织的无芽孢厌氧菌的检出情况不同。胃癌组织检出的主要为革兰氏阳性无芽孢厌氧菌 (优杆菌、丙酸杆菌、消化链球菌等 ) ,占检出菌株的 6 4 .86 %(48/74 ) ,其中硝酸盐还原实验阳性菌株为 5 9.4 6 % (44 /74 )。癌旁组织检出的主要为革兰氏阴性无芽孢厌氧菌 (类杆菌、梭杆菌、紫单胞菌、韦荣球菌 ) ,占检出细菌的 5 7.14 % (2 4 /42 ) ,硝酸盐还原实验阳性菌株为16 .6 7% (7/42 )。胃癌的病因受多种因素的影响 ,在胃癌组织中检测到无芽孢厌氧菌对胃癌的形成起到的作用 ,有待进一步研究。 相似文献
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Karakashev Dimitar Galabova Danka Simeonov Ivan 《World journal of microbiology & biotechnology》2003,19(3):233-238
A rapid qualitative test is proposed for bacterial respiratory type based on 24 h culturing of bacteria in liquid medium supplemented with a redox indicator: methylene blue or resazurin. Five reference bacterial strains with definite respiratory type as well as nine bacterial isolates from a laboratory digester for methane fermentation were used. Results obtained showed that both indicators can be used for distinction of strict aerobes from other bacterial representatives with definite respiration. In addition, the resazurin is able to differentiate strict anaerobes from microaerophiles and other anaerobes. The main advantages of the methylene blue is that it is a cheap, easily accessible dye, wide-used in microbiological practice and the results obtained with it are more stable over time. It was also noticed that the test with both indicators gave reliable results for the bacterial respiration only when an inoculum up to 48 h old was used. 相似文献
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无芽胞厌氧菌、Fas蛋白表达与胃癌相关性的研究 总被引:1,自引:0,他引:1
目的探讨无芽胞厌氧菌、Fas蛋白在胃癌及癌旁组织的表达情况及其临床意义。方法无芽胞厌氧菌的检测采用微生物分类鉴定系统中API20A测定方法,Fas蛋白的检测采用免疫组化SP法,分别检测了57例胃癌组织,57例癌旁组织,20例正常胃黏膜组织中微生物的变化及Fas蛋白表达。结果胃癌组织与癌旁组织的无芽胞厌氧菌检出情况不同。胃癌组织检出的主要为革兰阳性无芽胞厌氧菌(优杆菌、丙酸杆菌和消化链球菌等),占检出菌株的6486%(48/74),其中硝酸盐还原试验阳性菌株为5946%(44/74)。癌旁组织检出的主要为革兰阴性无芽胞厌氧菌(类杆菌、梭杆菌、紫单胞菌和韦荣球菌),占检出细菌的5714%(24/42),硝酸盐还原试验阳性菌株为1667%(7/42)。胃癌组织中Fas蛋白表达的阳性率为3509%(20/57),癌旁组织为7018%(40/57),正常胃黏膜为8500%(17/20),胃癌组织与癌旁组织、正常胃黏膜组织Fas蛋白的表达比较,差异均有非常显著性(P<001)。结论胃癌组织与癌旁组织的无芽胞厌氧菌检出情况不同。胃癌组织检出的主要为革兰阳性无芽胞厌氧菌。胃癌组织Fas蛋白水平的表达与癌旁组织、正常胃黏膜组织Fas蛋白的表达比较,差异均有非常显著性(P<001),对阐明胃癌的发生机制、预后和转移均有重要意义。 相似文献
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Tae Sik Hwang Byung Kwan Na Hung Thuan Tran Dae Hee Ahn Doo Hyun Park 《Biotechnology and Bioprocess Engineering》2008,13(6):677-682
In this study, a novel three-compartmented electrochemical bioreactor (3-CEB) was designed in an effort to overcome the disadvantages
of the two-compartmented electrochemical bioreactor (2-CEB) separated with a cation-selective membrane for enrichment of strict
anaerobes. The 3-CEB was comprised of an anode, outlet, and a cathode compartment. The outlet compartment was positioned between
the anode and cathode compartment, and it was separated with the anode side by a rubber plate and with the cathode side by
a porous glass membrane. A platinum wire bridging the anode and outlet compartment operated as a redox passage, however, through
which no material could permeate. Butyrate fermentation bacteria were enriched on the basis of the metabolite production.
Butyrate generated by strict anaerobes was significantly more abundant in the 3-CEB than in the 2-CEB. Acetic acid and lactic
acid generated by facultative anaerobes was relatively higher in the 2-CEB than in the 3-CEB. Meanwhile, butyrate was not
generated in the bioreactor utilized for the control test, to which the electrochemical potential was not charged. In a continuous
culture using the 3-CEB, the majority of the glucose was fermented to butyrate, and the acetate additionally supplied to the
bacterial culture was metabolically reduced to butyrate. More lactate than butyrate was generated from glucose in the 2-CEB. 相似文献
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Growth of a facultative anaerobe under oxygen-limiting conditions in pure culture and in co-culture with a sulfate-reducing bacterium 总被引:1,自引:0,他引:1
Abstract The occurrence and properties were studied of glucose-metabolizing bacteria present in the anaerobic sediment 5–10 cm below the surface of an estuarine tidal mud-flat. Of all these bacteria (104 – 105 per g wet sediment) 80–90% were facultatively anaerobic species. Chemostat enrichments on glucose under aerobic, oxygen-limited and alternately aerobic-anaerobic conditions also yielded cultures dominated by facultative anaerobes. One of the dominant species, tentatively identified as a Vibrio sp., was studied in more detail under oxygen-limiting conditions. Fermentative and respiratory metabolisms were found to operate simultaneously, and the ratio between the two was regulated by the extent of oxygen limitation. A small fraction of the acetate formed under such growth conditions was shown to be subsequently respired. A co-culture was established of the Vibrio sp. and a sulfate-reducing bacterium ( Desulfovibrio HL21 ) in an aerated chemostat. The importance of these observations is discussed in relation to the role of facultative anaerobes in anaerobic habitats. 相似文献
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G. Külekçi T. Bilgin S. Egilmez M. Turfaner Ö. Ang 《FEMS immunology and medical microbiology》1993,6(2-3):219-222
Abstract The aim of this study was to investigate whether black-pigmented Gram-negative anaerobes are part of the indigenous oral flora of edentulous subjects with or without dentures. Group I consisted of 11 subjects with dentures (mean age 63.6 years, range 52–75) and Group II consisted of 39 subjects with complete dentures in both jaws (mean age 59.3 years, range 37–80). Two microbial samples for microbiological examination were taken from each subject. One of them was from the dorsum of the tongue and the other was from saliva. Black-pigmented Gram-negative anaerobes > 107 cfu/ml were found in both samples. In 50 edentulous subjects, they were found more commonly from tongue (40%) than from saliva (26%). None of the subjects had Porphyromonas gingivalis . There was no statistically significant difference ( P > 0.05) between the presence of black-pigmented Gram-negative anaerobes on tongue and in saliva in the two groups. Our results suggested that high levels of black-pigmented Gram-negative anaerobes may belong to the indigenous oral flora in edentulous mouths with or without dentures. 相似文献
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Catalase and Superoxide Dismutase: Distribution, Properties, and Physiological Role in Cells of Strict Anaerobes 总被引:3,自引:0,他引:3
This review considers the distribution of the main enzymes of antioxidative defense, superoxide dismutase (SOD) and catalase, in various groups of strictly anaerobic microorganisms: bacteria of the genus Clostridium, Bacteroides, sulfate-reducing and acetogenic bacteria, methanogenic archaea, etc. Molecular and biochemical properties of purified Fe-containing SODs, cambialistic SODs, and heme catalases are presented. The physiological role and origin of the enzymes of antioxidative defense in strict anaerobes are discussed. Physiological responses (induction of SOD and catalase) to factors provoking oxidative stress in the cells of strict anaerobes able to maintain viability under aerobic conditions are also considered. 相似文献
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Dr. Yohichi Satoh 《Cell and tissue research》1988,251(1):87-93
Summary Germ-free mice were given live or heat-killed facultative anaerobes, and the ultrastructure of ileal Paneth cells was quantitatively examined with special reference to secretory granules showing a bipartite substructure (central core and peripheral halo). After administering live or heatkilled bacteria, there was a decrease in the area occupied by the cores of secretory granules in Paneth cells, and exocytosed core material was observed in the crypt lumen. There were no changes in the area occupied by the halo of secretory granules. None of the examined Paneth cells phagocytosed bacteria. It is concluded that certain bacteria may affect the secretion of antibacterial agents contained in the secretory granules of Paneth cells. 相似文献