Filter-feeder macroinvertebrates as key players in culturable bacteria biodiversity control: a case of study with Sabella spallanzanii (Polychaeta: Sabellidae)

The present study investigates the effect of the filtering activity of Sabella spallanzanii on the culturable heterotrophic bacterial community through the comparison of the bacterial diversity in transplanted polychaetes and the surrounding seawater. For isolation of culturable heterotrophic bacteria, seawater samples as well as polychaete homogenates were plated in triplicates onto Bacto Marine Agar 2216 (Difco). All the colonies grown were isolated, subcultured and identified by several morphological, biochemical and cultural methods. Some bacterial genera showed higher average abundances in polychaetes than in seawater (i.e. Lucibacterium and Photobacterium). Aeromonas represented a conspicuous component of the bacterial community both in S. spallanzanii and seawater. The presence of Cytophaga and Pseudomonas was also relevant in the examined seawater samples. The selective concentrations of some bacterial genera inside S. spallanzanii either by grazing on bacteria or their capability as bacterial reservoirs, provides evidence for the role of macrobenthic invertebrates as key determinants for microbial diversity.     

Microbial pollution indicators and culturable heterotrophic bacteria in a Mediterranean area (Southern Adriatic Sea Italian coasts)

In the present study we evaluated the degree of microbial water pollution along the coast line between Brindisi and Santa Maria di Leuca (Southern Adriatic Sea) as well as the culturable heterotrophic bacteria abundances and biodiversity in relation to the microbiological quality of the water. A total of 3773 colonies were isolated, subcultured and identified by several morphological, cultural and biochemical methods including the standardized API 20 E and API 20 NE tests. Along the examined coastal tract the microbial pollution indicators were always below the tolerance limits for bathing waters defined by the CEE directive, suggesting a good sanitary quality. Concerning culturable heterotrophic bacteria, different temporal density trends were observed in the four sites in relation to their geographical position. A positive relationship between the bacterial abundances and the temperature was observed in S. Cataldo and Otranto. The culturable bacterial community was mainly composed of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae family represented a conspicuous component of the bacterial community too. Bacilli were predominant among the Gram-positive bacteria. Of interest is the isolation of yeasts (2% at the surface and 1% at the bottom) taking into account their capability of biodegradation of various materials. Because of the low level of microbial pollution recorded, our results are indicative of the natural variation and diversity of the culturable bacterial community in such an oligotrophic ecosystem and could represent a good point of comparison with other ecosystems as well as a baseline for long term studies aimed to evaluate the effects of environmental fluctuations and human impacts on this aspect of biodiversity in coastal areas.     

Bacterial accumulation by Branchiomma luctuosum (Annelida: Polychaeta): a tool for biomonitoring marine systems and restoring polluted waters

In this study, we examined the bacterial accumulation in the filter feeder polychaete Branchiomma luctuosumGrube (Sabellidae). Analyses were performed on worm homogenates from 'unstarved' and 'starved' individuals, and seawater from the same sampling site (Gulf of Taranto, Western Mediterranean, Italy). Densities of culturable heterotrophic bacteria (22 degrees C), total culturable bacteria at 37 degrees C and halophilic vibrios at 22 and 35 degrees C were measured on Marine Agar 2216, Plate Count Agar and thiosulphate-citrate-bile-salt-agar (TCBS) plus 2% NaCl, respectively. Total and faecal coliforms as well as faecal streptococci were determined by the Most Probable Number method. Results showed that B. luctuosum is able to accumulate all the considered six microbiological groups with a higher efficiency for autochthonous bacteria. The analysis also indicated that bacterial groups differ in their resistance to digestion by B. luctuosum. Our data suggest the potential role of B. luctuosum as an useful bioindicator to assess low levels of microbiological water pollution as well as bioremediator of microbial polluted waters.     

北黄海微表层细菌丰度与可培养细菌群落结构分析

为分析海洋微表层这一特殊生境中的细菌类群,于2010—2011年4个航次对北黄海微表层和次表层海水中的总菌丰度、可培养细菌丰度和群落结构进行了分析。采用流式细胞仪测定总菌丰度,平板计数法测定可培养细菌丰度,PCR-16SrDNA分析可培养细菌的群落结构。结果表明,调查海域微表层海水总菌均值为1.76×106 cell/mL,次表层海水总菌均值为1.07×106 cell/mL。可培养细菌丰度范围是1.00×102~1.70×106 CFU/mL,微表层和次表层可培养细菌所占总菌数量的百分比分别为13.05%和0.45%。微表层对总菌的富集因子(EF)均值为2.02,可培养细菌的EF均值为74.16。PCR-16SrDNA序列分析结果表明,该海域可培养细菌分属变形菌门(Proteobacteria)(94.34%)、厚壁菌门(Firmicutes)(1.89%)、拟杆菌门(Bacteroidetes)(1.89%)和放线菌门(Actinobacteria)(1.89%)4个类群。本研究初步发现,微表层对细菌具有较强的聚集作用,尤其对可培养细菌聚集作用更为明显。微表层中可培养细菌的群落结构与次表层有所不同,其种类丰富,来源和功能多样。由此可见,微表层独特的生境成就了其独特的微生物类群,其生态功能有待于进一步研究。     

南极罗斯海区域可培养微生物分离鉴定及产低温酶能力初步筛选

为了利用南极微生物资源、探索南极罗斯海区域可培养微生物多样性,利用传统平板培养法对中国第33次南极科学考察采自南极罗斯海6个站位的海洋沉积物样品进行了细菌、真菌的分离培养。经细菌16S rRNA、真菌ITS基因序列检测及系统发育分析,共获得5个属的36株细菌和6个属的29株真菌。其中嗜冷杆菌属为优势细菌类群,枝孢属为优势真菌类群。该结果表明南极罗斯海区域具有丰富的微生物多样性。细菌API 20 NE生理生化及真菌产胞外酶活性实验显示,分离得到的细菌和真菌绝大多数都有低温酶活性。研究结果为南极罗斯海区域可培养微生物的多样性认识和低温酶产生菌资源获取与开发利用提供了支撑。     

南极菲尔德斯半岛可培养土壤微生物多样性及理化性质鉴定

为了探索南极可培养土壤微生物的多样性,本研究对中国第31次南极科学考察采集自南极菲尔德斯半岛的5份土壤样品进行了细菌、真菌的分离培养。选择形态差异较大的细菌和真菌进行了16S rDNA和ITS鉴定及系统发育分析。最终共鉴定得到20个属的33株细菌和6个属的8株真菌,其中8株细菌,10株真菌序列相似性较低,可能是新种。该结果表明南极菲尔德斯半岛地区具有丰富的微生物多样性,其中假单胞菌属的细菌居多。对分离得到的细菌和真菌分别进行理化性质和胞外酶活性鉴定,实验结果显示,分离获得的细菌和真菌绝大多数可产生水解酶类并同化多种碳源。初步认定这些微生物在参与南极物质代谢、适应南极极端环境方面发挥作用。本研究丰富了对南极菲尔德斯半岛可培养土壤微生物多样性的认识,并筛选获得了一些产低温酶特性的菌株,这为极地微生物资源的利用研究奠定了基础。     

渤海沉积物中细菌群落结构和基因丰度的空间分布特征

This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.     

Heterotrophic bacteria in the northern Adriatic Sea: seasonal changes and ectoenzyme profile

A seasonal study of the quantitative and qualitative distribution of heterotrophic bacterial community was carried out in the Adriatic Sea between April 1995 and January 1996, in order to evaluate its spatial and temporal variability and metabolic potential in the degradation processes of organic matter. The culturable bacteria (CFU) ranged between 0.1 and 22% of total bacterioplankton with a maximum percentage in surface samples of coastal zones. Their distribution was generally affected by the prevailing hydrological conditions. At the coastal stations about 44-75% of CFU variance could be explained by river runoff. The changes in the composition of heterotrophic bacterial community showed a seasonal succession of main bacterial groups, with a prevalence of Gram negative, non fermenting bacteria in the cold period (April-January) and an increase of Vibrionaccae and pigmented bacteria in summer. The seasonal variations were more important at the stations influenced by rivers than offshore. The bacterial community showed a greater versatility for organic polymers hydrolysis in the offshore station than in the coastal areas. Over 60% of all isolated heterotrophic bacteria expressed peptidase, lipase and phosphatase ectoenzymes activities, in all seasons and showed an increasing trend in warm period (in July October). The alpha- and beta-glucosidase potentials of bacteria were lower (20% on average) and showed different pattern during the year. These results suggest different role of the bacterial community in the decomposition of organic matter in the Adriatic Sea. Since only 20% of bacterial strains expressed glucosidase activity, carbohydrate-rich polymers such as mucilage might accumulate.     

Phylogenetic diversity of planktonic bacteria in the Chukchi Borderland region in summer

Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their diversity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization (FISH) showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic (AAP) bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria (Alpha, Beta and Gamma subclasses), Bacteroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone libraries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro-teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea.     

Heterotrophic bacteria community and pollution indicators of mussel--farm impact in the Gulf of Gaeta (Tyrrhenian Sea).

Field studies were carried out to determine and compare the impact of organic loads due to the biodeposition of a mussel farm on the water quality and sediment in a coastal area of the Tyrrhenian Sea (Western Mediterranean). A total of five environmental and five microbial parameters were examined from March, 1997 to February, 1998 on a monthly basis at three stations: the first was located under the mussel farm, the second located at about 40 m away from the mussel farm, while the third designed as a control was at about 1-km. No clear changes in the physical characteristics of the water masses were observed, comparing the three sampling sites and the water column generally showed homogeneous conditions (in terms of temperature and salinity). Changes in density of aerobic heterotrophic bacteria, Escherichia coli and Enterococci in the water column are apparently independent from changes in environmental parameters. At all stations a constant significant correlation between temperature and presumptive Vibrio parahaemolyticus was reported suggesting that this abiotic factor exerted a major control on this bacterial group and its distribution in the water column is not related to the biodeposition of the mussel farm. The major impact identified was on the sediment where variations in bacterial abundance was observed. In the Mussel station sediment enrichment of organic compounds, and the consequent modification of the characteristics of the benthic environment, determined an increase in aerobic heterotrophic bacteria, and particularly of vibrios density (on average about 60%), suggesting that these bacteria are good indicators of organic enrichment.     

北极海洋沉积物中可培养细菌及其多样性分析

利用Zobell 2216E培养基和涂布平板法对北极海洋沉积物中可培养细菌进行分离纯化,并利用16SrRNA基因进行分子鉴定与系统发育分析。根据菌落形态学特征,从59个站点的沉积物样品中共分离纯化获得570株细菌;基于16SrRNA基因的分子鉴定与系统发育分析表明,分离到的可培养细菌分别属于细菌域的4个门,5个纲,12个目,23个科,47个属,102个种,其中γ-Proteobactria占绝大多数;有14株菌株与模式菌株的16SrRNA基因序列相似性小于97%,为6个潜在的新种。北极海域的海洋沉积物中存在着丰富的微生物种质资源,为开发新型生物活性物质和特殊功能基因打下了基础。     

Heterotrophic bacteria of the Dapeng Bay in the South China Sea: community structure, abundance, and the relationships of culturablity with environmental factors

The community composition,abundance and culturablity of heterotrophic bacterioplankton in the Dapeng Bay of the South China Sea were investigated by morphological method,bacterial cultivation and biochemical methods over an annual cycle.Aeromonas and Pseudomonas were the predominant genera among the Gram-negative bacteria.The bacterioplankton abundance fluctuated from 2.07×10 8 to 2.44×10 9 cells/dm 3 ,and culturable bacteria abundance ranged between 0.1×10 6 and 16.07×10 6 CFU/dm 3 .The Culturablity of heterotrophic bacteria ranged between 0.01% and 1.31%.The relationship between bacterial culturablity and the environmental factors was also studied in different sites of the Dapeng Bay.Throughout the bay,a significantly positive relationship was evidenced between bacterial culturability and temperature,meanswhile bacterial culturability was significantly inversely related with salinity.The positive relationship was shown at the central bay while a negative relationship was observed at the bay mouth and there was no significant correlation at top bay between bacterial culturablity and chlorophyll a of sea water.A positive relationship was found between culturability and DIN all the bay,but DIP showed a significantly negative relationship with bacterial culturability only at the mouth of the bay.     

南海深海氮循环微生物的原位培养与多样性分析

借助自主研发的深海水体原位定植培养系统,在南海3 300 m的深海水体中进行了氮循环微生物的原位培养.通过向富集仓中投加缓释肥(铵盐、硝酸盐和尿素)进行了为期17个月的原位富集.结合高通量测序技术和分离培养的方法,对深海原位富集物及实验室二次富集物进行了微生物多样性分析. 16S rRNA基因高通量测序结果表明,在南海原位富集样品中,细菌以变形菌门丰度最高,富集仓内脱脂棉附着介质和仓内水样中的最优势属分别为希瓦氏菌属(Shewanella)和科韦尔氏菌属(Colwellia);古菌以奇古菌门为主,其中氨氧化古菌(AOA)所占比例很高.通过平板培养分离到17株细菌,主要包括盐单胞菌属(Halomonas)、海杆菌属(Marinobacter)和亚硫酸盐杆菌属(Sulfitobacter)等.通过不同起始氮源(氨氮、硝酸盐、亚硝酸盐)和培养温度(28℃和10℃),对原位富集样品进行实验室二次富集,获得了5个富集菌群.分析发现,它们均具有较好的脱氮效果,可以产生N_2O或N_2;这些菌群均以盐单胞菌属占绝对优势,其次为海源菌属(Idiomarina)或海杆菌属,其中盐单胞菌和海源菌成功获得分离.单菌功能验证表明,分离获得的盐单胞菌具有好氧反硝化能力,其在原位环境下反硝化活性尚有待确认.     

南海沉积物细菌胞外蛋白酶在家族水平上的多样性

海洋产蛋白酶细菌及其分泌的胞外蛋白酶在降解有机氮以推动海洋氮循环进行方面发挥着重要作用,但目前对这二者多样性的认识非常有限。本研究自南海沉积物中筛选得到90株产蛋白酶细菌,并通过N-端氨基酸序列,分析了其胞外蛋白酶在家族水平上的多样性。16S rRNA基因序列分析的结果表明,筛选的产蛋白酶细菌均属于Gammaproteobacteria纲,且大多数属于Alteromonadales目和Vibrionales目的不同属。对其中14株菌株的14个胞外蛋白酶的N-端氨基酸序列分析表明,所有这些蛋白酶属于金属蛋白酶的M4家族或丝氨酸蛋白酶的S8家族。本研究提供了海洋沉积物产蛋白酶细菌在类群及其胞外蛋白酶在类型上的新细节,这将有助于全面了解微生物酶促降解海洋沉积物有机氮的过程和机理。     

海南红树林根系土壤中可培养细菌的多样性分析

为研究海南红树林根系土壤细菌多样性,充分发掘中国红树林特有微生物资源,作者于2012年12月份从10份采集于海南北港岛红树林根系淤泥样品中分离可培养海洋细菌,并基于16S rRNA基因序列分析的方法对样品中的细菌多样性进行研究。共分离得到122株海洋细菌,经并菌后选取其中的70株代表性菌株测序,结果发现它们分为4个类群:变形菌门(主要为γ-变形菌纲)(Proteobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和放线菌门(Actinobacteria),分别占66%,19%,11%和4%。共代表30个属47个种,其中有9个潜在新种和2个潜在新属。本研究结果表明,北港岛红树林中存在着丰富的细菌多样性,很多类群可能是红树林特有细菌物种。     

黄海西北近岸沉积物中细菌群落空间分布特征

采用16S rDNA文库和变性梯度凝胶电泳(DGGE)技术,对黄海西北部3个近岸站位沉积物中细菌群落多样性及空间分布特征进行了调查和解析。对表层沉积物16S rDNA序列统计表明,各站位细菌群落多样性很高,γ-和δ-变形菌纲分别占克隆序列总数的20%~32%,是沉积物中的绝对优势类群。DGGE图谱分析表明,同一站位中不同深度的细菌群落结构相似性较高,而不同站位间群落结构相差较远。研究表明在黄海西北近岸沉积物中细菌群落多样性较高,优势类群明显,在较小尺度范围内群落结构的垂直变化不明显。     

广西茅尾海红树林土壤放线菌多样性及功能酶活性研究

研究广西茅尾海红树林自然保护区内红树林土壤中可培养放线菌的多样性,挖掘具有高产多种功能酶活性的放线菌类群.应用可培养技术和基于16S rRNA基因序列的系统发育分析研究红树林土壤中可培养放线菌的多样性;并以10种酶活底物为指示物,结合点植法和透明圈法对可培养的放线菌进行功能酶活性筛选.结果显示,从红树林土壤中共分离到4...     

Particulate materials and microbial assemblages around the Izena black smoking vent in the Okinawa trough

The plume of particulate DNA (0.7–1g/l) was extended from a black smoker vent (c.a. 1340 m depth) to the west-southwest directions in the Izena bottom-water region. High concentrations of particulate materials (70–110 g C/l; 300–570 g S/l) were also detected in the bottom-waters. Microscopic observation showed that the bottom-waters were rich in alcian blue-stainable large amorphous particles which contained coccoid and rod-shaped microbial cells mostly smaller than 1m. These microbial matrix compounds appeared to contribute to low P-DNA/P-C ratio (0.011±0.008;n=27) in the vent environment. Sulfur was detected in various kinds of particles in the waters, while the content varied with calcium. Microbial population in the P-DNA plume water was in the order of 10⁵ cells/ml and the most (>99.9%) were non-culturable. The composition of culturable heterotrophs differed between the bottom-waters and surface sediments surrounding the vent; contributions of low temperature (4°C)-culturable bacteria and manganese-oxidizing bacteria to the total heterotrophs were higher in the sediments than in the waters. In contrast, percentages of orange-pigmented heterotrophs and microorganisms capable of growing in thiosulfate- and ammonia-based media to the total heterotrophs were higher in the waters than in the sediments. These results suggest that the culturable bacterial community in the bottom-waters was nutritionally versatile. Izena hydrothermal activities seemed to have a great influence in concentrations and compositions of particulate mateirals and in biomass and compositions of microbial community in the vicinity of this aphotic deep-sea environment.     

海洋新菌的分类与鉴定方法

细菌的分类鉴定与细菌的研究和应用有着同等重要的地位。目前从自然界中可以培养的细菌总量不到1%,大多数海洋细菌的分类鉴定仍需建立在纯培养基础上。本文对目前可培养海洋细菌的分类鉴定方法做了系统的综述,详述了系统发生树的构建,汇总了生理生化分类特征,概述了主要的遗传学分析方法,包括16S rDNA序列分析,G+C含量测定,DNA-DNA杂交,MLST(多位点序列分型,Multi Locus Sequence Typing)以及核酸指纹图谱等,并指出每种方法适用的范围以及应用时需要注意的事项。另外,本文还提出了新菌分类鉴定的一般步骤。文章最后对目前海洋细菌分类鉴定的发展趋势进行了总结和展望。     

印度洋深海沉积物样品纯培养细菌的分离鉴定

为探索印度洋深海沉积物中纯培养细菌的多样性,本文对采自印度洋12个沉积物样品进行细菌纯培养分离,共获得343株细菌.所有细菌采用16S?rRNA基因进行比对分析,鉴定为4个门:厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和拟杆菌门(Bacteroi...