紫色非硫细菌光合基因表达调控研究进展

紫色非硫细菌光合基因表达调控研究进展吴大庆,钱新民（山东大学微生物所,济南２５０１００）紫色非硫细菌ｐｕｒｐｌｅｎｏｎｓｕｌｆｕｒｂａｃｔｅｒｉａ,以下简称ＰＮＳ菌,即红螺菌科（Ｒｈｏｄｏｓｐ－ｉｒｉｌｌａｃｅａｅ）,属于光合细菌的α和β亚门,具有较...     

一株紫色非硫光合细菌净化养殖水体初步研究

选取从杭州养鱼塘水样中分离得到的1株紫色非硫光合细菌菌株HZ-1,利用它的纯培养物处理养殖水体,测定COD去除率和亚硝态氮降解率。结果表明,菌株HZ-1可以有效地分解水体中的污染物,去除水体中的COD,对养鱼塘水去除率达到20.99%;对养虾池水去除率达到了36.09%;菌株HZ-1可以有效地降低水体的亚硝态氮,对养鱼塘水亚硝态氮的降解率为41.18%,具有较好净化效果。     

阳宗海和滇池中紫色非硫细菌数量和种群结构的比较

在2002年平水期对高原湖泊阳宗海和滇池中的紫色非硫细菌(PNSB)数量和种群结构进行了比较研究。对两湖中的各因子进行t检验,发现各因子和PNSB数量都有极显著差异,富营养化湖泊滇池中的PNSB数量远远多于贫营养化湖泊阳宗海;两湖中PNSB的优势种是红假单胞菌属,也有少数的红螺菌属。两湖种群结构的区别是滇池有红微菌,而阳宗海有大量红细菌。     

净化养殖水体紫色非硫光合细菌的筛选与鉴定

本研究从杭州养鱼塘水样及底泥样品中富集分离得到三株紫色非硫光合细菌,分别命名为HZ-3,HZ-4,HZ-5。 通过比较这三株菌对鱼、虾养殖水体的净化效果,筛选出菌株HZ-5 净化能力较强 ,经过5天的处理,该菌株使养鱼塘水样的COD 降低24.87%;使养虾池塘水样的COD 降低 36.99%;使养鱼塘水样的亚硝态氮的降解率达到97.79%。对菌株HZ-5进行了形态学观察、生理生化鉴定、活细胞吸收光谱以及16S rDNA序列分析。16S rDNA序列分析结果表明该菌株与沼泽红假单胞菌的16S rDNA序列有高达99％的同源性,结合形态特征和生理生化特性以及活细胞吸收光谱特征等,将其鉴定为沼泽红假单胞菌（Rhodopseudomonas palustris）。     

内蒙古碱湖中紫色非硫光合细菌的分离和鉴定

从内蒙古碱湖水样中分离得到一株紫色非硫光合细菌,命名为JH1-6.对该菌株进行了形态学观察、生理生化鉴定、活细胞吸收光谱以及16S rDNA序列分析.16S rDNA序列分析结果表明该菌株与沼泽红假单胞菌的16S rDNA序列同源性高达99%,结合形态特征和生理生化特性以及活细胞吸收光谱特征等,确定菌株JH1- 6在分类地位上属于沼泽红假单胞菌(Rhodopseudomonas palustris).     

紫色非硫细菌质粒的制备与性质

介绍一种适于紫色非硫细菌质粒的制备方法,该法简单,易操作,质粒ＤＮＡ纯度好,收率高,通过在加富培养基上连续传代数次,质粒ＤＮＡ可自行消除。     

紫色非硫细菌的砷代谢机制

[目的]系统阐述紫色非硫细菌(PNSB)砷代谢机制和砷代谢基因簇的进化关系.[方法]通过生物信息学方法分析了PNSB砷代谢基因簇的分布、组成、排布方式.采用UV-Vis和HPLC-ICP-MS方法,研究了3个PNSB种类对砷的抗性、砷形态及价态的转化、砷在细胞中的积累和分布以及磷酸盐对As细胞毒性的影响.[结果]砷基因簇分析表明:已公布全基因组序列的17个PNSB菌株基因组中均含有以ars operon为核心的砷代谢基因簇,由1-4个操纵子组成,主要含有与细胞质砷还原和砷甲基化代谢相关的基因,但基因的组成和排列方式因种和菌株而异,尤其是arsM和两类进化来源不同的arsC.实验结果表明:光照厌氧条件下,3个PNSB种类对As(V)和As(Ⅲ)均具有抗性,As(V)和As(Ⅲ)均能进入细胞 ;在胞内As(V)能够还原为As(Ⅲ)并被排出胞外,但不能将As(Ⅲ)氧化为As(V),也未检测到甲基砷化物 ;磷酸盐浓度升高,能够抑制As(V)进入细胞,降低As(V)对细胞的毒性,而不能抑制As(Ⅲ)进入细胞.[结论]PNSB砷代谢机制主体为细胞质As(V)还原,也还有砷甲基化途径.通过对砷代谢基因簇结构多样性特点和进化方式分析,提出了与Rosen不同的ars operon进化途径.这对深入开展PNSB砷代谢和基因之间的相互作用研究奠定基础.     

紫色非硫细菌固体石蜡双层平板培养法

紫色非硫细菌是一类不产氧光合细菌,具有重要的生态学意义和应用价值。建立固体石蜡双层平板法,与传统的培养法相比较,发现该方法可以更方便、更快捷地计数和分离紫色非硫细菌。结合分子生物学技术,将该方法应用于水稻土紫色非硫细菌的研究,发现以甲酸为碳源的固体石蜡双层平板法可以很好地对环境中可培养的紫色非硫细菌多样性进行研究。该方法的建立将更有助于紫色非硫细菌的研究。     

紫色非硫细菌Rhodocista属一新分离株的鉴定及其系统学研究

从污水处理厂分离到一株紫色非硫细菌３－ｐ,该菌株具避光性,能形成孢囊,具片层状光合内膜,在波长７９８ｎｍ处的吸收峰很低,需硫胺素和维生素Ｂ１２作生长因子。该菌株可以琥珀酸为碳源,最佳生长温度为３４℃～４１℃,体内未发现Ｒ体结构,醌类的主要成分是Ｑ－９。对菌株３－ｐ的１６Ｓ ｒＲＮＡ基因的分子系统学分析结果表明,菌株３－ｐ与世纪红蒌菌（Ｒｈｏｄｏｃｉｓｔａ ｃｅｎｔｅｎａｒｉａ）关系最近,相似性为９     

产氢紫色非硫光合细菌的分离与筛选

从不同来源的样品中分离到5株紫色非硫光合细菌,从中筛选出2株产氢量较高的菌株——菌株D和菌株H。对其产氢动力学研究表明,在含有20mmol/L谷氨酸钠和50mmol/L D,L-苹果酸培养基中,两株菌可连续稳定产氢5—8d,其产氢速率分别为10.18和20.61μ/h·mg细胞干重。     

Field and Laboratory Studies on some Photosynthetic Bacteria in Aswan High Dam Lake. II. Isolation and Identification of Purple Non-sulfur Bacteria (Rhodospirillaceae)

485 isolates were recorded from different localities between summer 1984 and spring 1985. These isolates comprise five different genera with eight different species of purple non-sulfur bacteria- Rhodopseudomonas was the most common genus at all sites and was represented by three species. R. acidophila, R. blastica, R. palustris. Rhodomicrobium was the second in frequency and was represented by R. vannielli only. This species was only recorded for khor sites. Rhodocyclus was represented by two species, R. gelatinosus and R. tenuis. Rhodobacter and Rhodospirillum were represented by one species each, Rhodobacter capsulatus and Rhodospirillum rubrum. Khor sites were richer in number of isolates and genera of purple non-sulphur bacteria than the main body of AHDL. Some species were more common in winter and spring while others predominate in summer and autumn.     

Community structure of Archaea and Bacteria in a profundal lake sediment Lake Kinneret (Israel)

The microbial community structure of an anoxic profundal lake sediment, i.e., subtropical Lake Kinneret, was analysed with respect to its composition by culture-independent molecular methods including terminal restriction fragment length polymorphism (T-RFLP) analysis, comparative sequence analysis, and quantitative real-time PCR. In particular we were interested in the structure, species composition, and relative abundance of the overall microbial community in the methanogenic sediment layer (0-10 cm depth). Pairwise comparison of archaeal and bacterial 16S rRNA gene T-RFLP profiles obtained from three independent samplings indicated stability of the microbial community. The numbers of Archaea and Bacteria, quantified by real-time PCR, amounted to about 10(8) and 10(10) 16S rRNA gene copies cm(-3) sediment, respectively, suggesting that Archaea may account for only a minor fraction (approximately 1%) of the total prokaryotic community. Hydrogenotrophic Methanomicrobiales and acetoclastic Methanosaeta spp. dominated T-RFLP profiles of the archaeal community. T-RFLP profiles of the bacterial community were dominated by Deltaproteobacteria, sulphate reducers and syntrophs in particular. The second most abundant group was assigned to the Bacteroidetes-Chlorobi-group. Only one bacterial group, which was affiliated with halorespiring bacteria of subphylum II of the Chloroflexi, showed variation in abundance within the sediment samples investigated. Our study gives a comprehensive insight into the structure of the bacterial and archaeal community of a profundal lake sediment, indicating that sulphate reducers, syntrophs, bacteroidetes, halorespirers and methanogens are of particular importance in Lake Kinneret sediment.     

微生物分子生态学技术在湖泊微生物多样性研究中的应用

微生物是湖泊生物圈物质循环和能量流动的主要参与者,在湖泊的生态系统中起着重要的作用。但是,湖泊中存在着大量不可培养的细菌,利用传统的培养技术,无法对湖泊微生物的多样性进行深入而全面的研究,而不依赖培养的分子生物学技术的发展为此方面研究开辟了新的路径。微生物分子生态学作为分子生物学与微生物生态学交叉产生的学科,在研究湖泊微生物多样性方面已经得到了广泛的应用。主要综述了变性梯度凝胶电泳(PCR-DGGE)技术,末端限制性酶切片段长度多态性技术(T-RFLP),16SrDNA克隆文库技术等微生物分子生态学技术在研究湖泊微生物多样性方面的应用情况。     

Sibling species complexes in sympatric populations of Petrotilapia Trewavas (Cichlidae, Lake Malawi)

The endemic Lake Malawi cichlid, Petrotilapia tridentiger Trewavas, was found to be a complex of sibling species. The various sympatric species show considerable homogeneity in body form and dentition but are separable on the basis of differences in adult coloration, size at maturity, depth distribution, size and degree of overlap of territories, aggression and courtship. Colour is considered to be important for specific mate recognition in this genus. Examination of wild populations is a valuable, perhaps essential, adjunct to classical taxonomy when dealing with the systematics of sibling species in Lake Malawi.     

Isolation and Characterization of Organic Phosphorus-Mineralizing Bacteria in Sediment of a Chinese Large Shallow Eutrophic Lake (Lake Taihu)

The organic phosphorus mineralizing bacteria (OPB) play an important role in phosphorus cycling in lake sediment, to which less attention has been paid. Monthly sediment samples in 2009 ending in October, together with the samples from different seasons (May, July, October, and December) in 2008, were collected at 6 sites in a Chinese large shallow eutrophic lake (Lake Taihu). The sediment OPB numbers ranged from 2.2 × 10⁶ to 1.79 × 10⁸ cells g^?1 (dry weight) at different sampling sites and in different seasons, with the average being 3.88 × 10⁷ cells g^?1 (dry weight). Its number was highest at the most polluted site and peaked in spring and summer, which can be explained by the enrichment of organic matter in sediment. Furthermore, there existed a significant positive relationship between the OPB numbers and alkaline phosphatase activities in the sediment. The 6 OPB strains isolated from the sediment were distinct in terms of their colony morphology on the yolk agar, biochemical characteristics and phosphorus release abilities. According to the 16S rDNA sequences, these OPB belong to Bacillus cereus, Stenotrophomonas maltophilia, Stenotrophomonas sp., Bacillus cereus, Xanthomonas sp., Pseudomonas sp. They were distinguished from the OPB species recorded in a Chinese small shallow eutrophic lake whose sediment organic content was remarkably higher. Taken together, organic matter shaped the OPB community not only quantitatively but also qualitatively, which in concert facilitated the enzymatic hydrolysis of organic phosphorus in lake sediment.     

Analysis of Subfossil Molecular Remains of Purple Sulfur Bacteria in a Lake Sediment

Molecular remains of purple sulfur bacteria (Chromatiaceae) were detected in Holocene sediment layers of a meromictic salt lake (Mahoney Lake, British Columbia, Canada). The carotenoid okenone and bacteriophaeophytin a were present in sediments up to 11,000 years old. Okenone is specific for only a few species of Chromatiaceae, including Amoebobacter purpureus, which presently predominates in the chemocline bacterial community of the lake. With a primer set specific for Chromatiaceae in combination with denaturing gradient gel electrophoresis, 16S rRNA gene sequences of four different Chromatiaceae species were retrieved from different depths of the sediment. One of the sequences, which originated from a 9,100-year-old sample, was 99.2% identical to the 16S rRNA gene sequence of A. purpureus ML1 isolated from the chemocline. Employing primers specific for A. purpureus ML1 and dot blot hybridization of the PCR products, the detection limit for A. purpureus ML1 DNA could be lowered to 0.004% of the total community DNA. With this approach the DNA of the isolate was detected in 7 of 10 sediment layers, indicating that A. purpureus ML1 constituted at least a part of the ancient purple sulfur bacterial community. The concentrations of A. purpureus DNA and okenone in the sediment were not correlated, and the ratio of DNA to okenone was much lower in the subfossil sediment layers (2.7 · 10⁻⁶) than in intact cells (1.4). This indicates that degradation rates are significantly higher for genomic DNA than for hydrocarbon cell constituents, even under anoxic conditions and at the very high sulfide concentrations present in Mahoney Lake.     

Methanogenesis in the hypersaline Solar Lake (Sinai)

Abstract Enrichment studies on microbial mat sediments (potential stromatolites) from the hypersaline Solar Lake (Sinai) indicated high numbers of methanogenic bacteria (up to 10⁵ ml⁻¹ sediment) in spite of the high sulfate reduction rate, sulfate concentration and salinity. Among H₂/CO₂, acetate and monomethylamine, the methylated amine was the preferred substrate. The predominant species enriched was a Methanosarcina sp. The findings indicate that methanogenic bacteria play an important role in hypersaline sulfate-enriched anoxic sediments and stromatolithic microbial mats.     

Late Quaternary palaeohydrology of Lake Huinaymarca (Bolivia)

In lake Titicaca, the distribution of the modern ostracod fauna appears to be controlled by a combination of two factors: a) the equilibrium between carbonates and organic matter, b) the ionic composition of the lake water and its tributaries. Therefore, the Limnocythere-Pampacythere group generally predominates on an alkaline-carbonate lake floor. In parts of the lake receiving an NaCl input from tributaries, Cyprideis and Cyprinotus occur. These are generally absent elsewhere. The Candonopsis group is found in the deepest part of the lake.Analysis of ostracod assemblages recovered from a number of cores permitted the reconstruction of the hydrological evolution of lake Huinaymarca for the last 10000 years. This included: low water levels, variations of oxygenation related to the position of the thermocline, and interconnections between different basins of the lake.     

Description of a commercially important pelagic species of the genus Diplotaxodon (Pisces: Cichlidae) from Lake Malawi, Africa

A new species of pelagic haplochromine cichlid of the genus Diplotaxodon is described from Lake Malawi, Africa. The species, which attains a size of 14cm s. L., feeds mainly on zooplankton, shows no sexual dimorphism in size or body proportions, breeds throughout the year and lives at depths of 20 to at least 120 m. Approximately 600 tonnes of the species were caught by trawlers in 1990–1991, in the south–eastern arm of the lake alone. It appears that this species is a major component of the pelagic community, and occupies an ecological role similar to that of the clupeid Limnothrissa miodon in Lake Tanganyika.