柴达木盆地新近纪叠层石中微生物化石组合的发现与钙化方式研究   总被引：2，自引：0，他引：2  

温志峰  刘显太  钟建华  李勇  王海侨 《地质学报》2010,84(2):263-271

在柴达木盆地西部新近纪叠层石纹层中第一次明确发现了保存完好的微生物化石,其中包括微米级别的微生物球状构造,亚微米级的生物颗粒构造以及矿化的席状和片状有机组织。结合目前国内外的研究成果可以确定暗层中微米级球状构造为类似于Coccoid的硫还原微生物,亚微米的球状颗粒一方面是叠层石微生物席胞外聚合物质(EPS)的重要组成部分,另一方面也是极端条件下微生物体脱水收缩以后的产物,而片状和席状构造则是矿化的EPS以及微生物膜。通过对亮层和暗层中生物构造、石英、石盐以及方解石矿物的分析,可以确定叠层石的形成过程分为暗层有机主动矿化和亮层无机原地沉淀,其中的暗层矿化则分为上层封闭酸性环境中的光合作用,以及下层相对封闭环境中的硫还原和EPS的降解钙化作用,上部的亮层则主要为原地沉淀无机成因并在成岩过程中受到了暗层中有机质的影响。  相似文献   

杉木林表层和底层土壤微生物生长对策的研究     

吴佳斌  陈玉平  陈碧燕  杨智杰  陈光水 《亚热带资源与环境学报》2012,7(4):78-81

底层土壤有机碳库占土壤总碳库的50％以上,但其控制机理仍不清楚．本研究以福建建瓯万木林自然保护区的杉木人工林为研究对象,采用改进的酶动力学分析方法,研究杉木林表层（0～10cm）和底层（40—60cm）土壤微生物生长对策的差异．结果显示,相对于表层土壤,底层土壤的易利用碳含量更高,表层土壤微生物更趋向于K对策,而底层土...  相似文献   

Cr(Ⅵ)抗性菌株的筛选及其Cr(Ⅵ)去除特性研究   总被引：3，自引：0，他引：3  

吴淼  汤岳琴  于萍  周元祥  吴晓磊 《岩石矿物学杂志》2009,28(6):520-526

采用微生物分离纯化方法,从制革厂含铬污泥中筛选分离Cr (Ⅵ)抗性菌株,并研究菌株对Cr(Ⅵ)的去除能力.共分离得到对50 mg/L Cr(Ⅵ)去除率大于50%的菌株20株,16S rRNA基因测序结果表明这些细菌主要属于Acinetobacter、 Microbacterium、Leucobacter、Ochrobactrum和Brachymonas属.对其中7株细菌,考察了菌株生长期、pH值和Cr(Ⅵ)浓度对菌株去除Cr(Ⅵ)效果的影响,结果表明,细胞在有较高代谢活性的条件下具较高的Cr(Ⅵ)去除能力;pH值对菌株去除Cr(Ⅵ)的能力具有显著影响,在50 mg/L Cr(Ⅵ)、pH值为7～8的条件下,Microbacterium属16号和21号菌株在36 h时对Cr (Ⅵ)的去除率达80%～95%;高浓度的Cr(Ⅵ)抑制菌株对Cr(Ⅵ)的去除能力,其中21号菌株在110 mg/L的Cr(Ⅵ)浓度下去除效果最佳,Cr(Ⅵ)去除率达80%.  相似文献   

基于低压变频电场技术对带鱼(Trichiurus lepturus)保鲜过程中微生物群落影响分析          下载免费PDF全文

史恬恬  谢超  张家玮  李远慧  朱亚猛  吴玉婷  周卓颖  虞舟 《海洋与湖沼》2022,53(1):133-140

带鱼(Trichiurus lepturus)在低温条件运输和贮藏过程中,易受微生物和内源性蛋白酶的影响而产生胺类和醛类物质导致腐败。为了研究低压变频电场对微冻带鱼在贮藏过程中的微生物群落特征,采用Miseq基因组测序技术,对贮藏至40d的舟山带鱼的微生物群落进行碱基信息测序。将产生的碱基序列通过OTU聚类、多样性分析、相关性分析等手段分析了影响带鱼保鲜效果的微生物群落组成和发育信息。在此基础上,研究了不同强度电场(0,2,2.5,3 kV/m)处理对带鱼微生物群落组成的影响。根据菌属相对丰度结果,推测希瓦氏菌属(Shewanella)、假单胞菌属(Pseudomonas)、紫色杆菌属(Janthinobacterium)是带鱼微生物腐败主要致腐菌。结果表明,40 d后,经3 kV/m处理的样品其OTU6嗜冷菌属和OTU13假单胞菌属c的相对丰度均小于1%,而且OTU7、OTU14、OTU8、OTU9等菌属未被OTU聚类。结果表明,经3kV/m电场强度的低压静电场处理的抑菌保鲜效果最好,表现为在贮藏过程中杂菌种类最少,样本微生物群落物种丰度和多样性均最低,腐败程度最低。  相似文献   

珠母贝糖胺聚糖胶囊制备与检测     

叶庆俊  范秀萍  吴红棉 《广东海洋大学学报》2008,28(3)

以马氏珠母贝糖胺聚糖粗品为主要功能成分,以β-环糊精为辅料,制成珠母贝糖胺聚糖胶囊,并进行检测。结果表明:该胶囊中水分、总糖、糖胺聚糖(GAG)和粗蛋白质量分数分别为8.85%、85.23%、3.00%和3.60%;胶囊的装量差异与崩解时限均符合质量标准;胶囊制剂中细菌总数小于1000 g-1,大肠杆菌MPN小于30 g-1,霉菌和酵母菌总数小于25 g-1,符合《保健食品通用卫生要求》规定;致病菌均未检出。  相似文献   

Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: 2. The Pit Borers   总被引：1，自引：0，他引：1  

James E.  Hook Stjepko  Golubic 《Marine Ecology》1990,11(3):239-254

Abstract. Mussel periostracum from the Florida Escarpment redox community (3266 m depth) is extensively bored by a variety of microorganisms. Four different types of pit borings were observed and characterized on the basis of SEM images of their resin casts, and/or light and TEM reconstructions: two large, open-pit borers, a "button" borer, and a cone borer. These boring patterns represent distinctive feeding "strategies". The cumulative activities of periostracum borers remove the protective organic layer from the mussel shells, exposing the mineral to cndolith attack.  相似文献   

两种水质处理方式对养虾池内弧菌数量变化的影响   总被引：3，自引：1，他引：3  

王志成  廖思明  童万平 《台湾海峡》2005,24(4):508-514

在两个对虾养殖场，采用不同的水质处理方式养殖凡纳滨对虾（Lhopenaeus vannamei，俗称南美白对虾），并对池内及其附近海域的弧菌数量、水化因子进行跟踪监测．结果表明使用有益微生物制剂处理水质的两口养殖池弧菌数量明显减少，弧菌细胞密度均值分别为535、918个／cm^3，对虾生长正常，水质稳定．另一使用消毒剂处理水质的养殖场弧菌数量较高，两口监测池的弧菌细胞密度均值分别达到373l、4182个／cm^3，且水色变化较大，对虾出现体色异常现象．  相似文献   

Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: The Scalloping Periostracum Borer     

James E.  Hook Stjepko  Golubic 《Marine Ecology》1988,9(4):347-364

Abstract. A complex and highly unusual eukaryotic microorganism was discovered to be penetrating and removing the periostracum of deep-sea mussels from the Florida Escarpment brine seeps at a depth of 3266 m. These brine seeps support a chemolithoautotrophic redox community similar to those known from Pacific hydrotherma! vents. This microorganism of unknown taxonomic affinity is filamentous and coenocytic, with a simple plasma membrane and no cell wall. It forms prostrate, radiating systems of branched tunnels, 8–15 u.m in diameter. The surface of the tunnels is sculptured by helically organized, scale-like depressions, which are left as scars in the process of periostracum removal by the organism. Periostracum is removed in discrete pieces (scallops) at the ends of the tunnels. This organism has been found at three Atlantic deep-sea redox communities, but not in similar communities of the Pacific.  相似文献   

羟基对微生物细胞的核酸、蛋白质、葡萄糖作用研究     

张芝涛  白希尧  沈欣军  胡又平 《海洋技术学报》2003,22(4):22-26

羟基自由基对细胞的三大基本分子核酸、蛋白质、葡萄糖有着强烈破坏作用。压载水中羟基的比值浓度达到0．63mg／L时，含有微生物液体中的总蛋白质含量从1．49g／100mL降到0．993g／100mL，减少了33．4％；核酸中RNA、DNA的含量分别从2．43μg／mg、0．96μg／mg分别减少到1．29μg／mg、0．19μg／mg，分别减少46．9％、80．2％；葡萄糖含量从0．246mg／100mL增加到0．492mg／100mL，增加了1倍。试验数据表明，羟基自由基氧化、分解、破坏了微生物细胞三大基本分子核酸、蛋白质、葡萄糖，这是微生物致死的主要生化原因之一。  相似文献   

Effects of hydrostatic pressure on microbial alteration of sinking fecal pellets     

Christian Tamburini  Madeleine Goutx  Catherine Guigue  Marc Garel  Dominique Lefvre  Bruno Charrire  Richard Sempr  Stphane Pepa  Michael L. Peterson  Stuart Wakeham  Cindy Lee 《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(18):1533-1546

We used a new experimental device called PASS (PArticle Sinking Simulator) during MedFlux to simulate changes in in situ hydrostatic pressure that particles experience sinking from mesopelagic to bathypelagic depths. Particles, largely fecal pellets, were collected at 200 m using a settling velocity NetTrap (SV NetTrap) in Ligurian Sea in April 2006 and incubated in high-pressure bottles (HPBs) of the PASS system under both atmospheric and continuously increasing pressure conditions, simulating the pressure change experienced at a sinking rate of 200 m d⁻¹. Chemical changes over time were evaluated by measuring particulate organic carbon (POC), carbohydrates, transparent exopolymer particles (TEP), amino acids, lipids, and chloropigments, as well as dissolved organic carbon (DOC) and dissolved carbohydrates. Microbial changes were evaluated microscopically, using diamidinophenylindole (DAPI) stain for total cell counts and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) for phylogenetic distinctions. Concentrations (normalized to POC) of particulate chloropigments, carbohydrates and TEP decreased under both sets of incubation conditions, although less under the increasing pressure regime than under atmospheric conditions. By contrast, dissolved carbohydrates (normalized to DOC) were higher after incubation and significantly higher under atmospheric conditions, suggesting they were produced at the expense of the particulate fraction. POC-normalized particulate wax/steryl esters increased only under pressure, suggesting biochemical responses of prokaryotes to the increasing pressure regime. The prokaryotic community initially consisted of 43% Bacteria, 12% Crenarchaea and 11% Euryarchaea. After incubation, Bacteria dominated (90%) the prokaryote community in all cases, with γ-Proteobacteria comprising the greatest fraction, followed by the Cytophaga–Flavobacter cluster and α-Proteobacteria group. Using the PASS system, we obtained chemical and microbial evidence that degradation by prokaryotes associated with fecal pellets sinking through mesopelagic waters is limited by the increasing pressure they experience.  相似文献