具有多种胞外酶的对虾肠道黏附菌的分离和鉴定     

刘慧玲  罗鹏  杨世平  李广聪  莫嘉文  王蔚 《广东海洋大学学报》2012,(3):1-5

用对虾饲料培养基从健康凡纳滨对虾肠道分离出500株黏附细菌,以产淀粉酶、脂肪酶和蛋白酶能力为指标,筛选出产该3种消化酶的细菌90株,占总菌株的18%.对其中生长较快的69株进行16S rDNA 基因测序,确定其分类地位.结果显示,69株菌分别属于不动杆菌属(Acinetobacter)、芽孢杆菌属(Bacillus)、葡萄球菌属(Staphylococcus)、假交替单胞菌属(Pseudoalteromonas)、气单胞菌属(Aeromonas)、嗜盐单胞菌属(Halomonas)、利斯顿氏菌属(Listonella)、莫拉氏菌属(Moraxella)等,其中数量最多是芽胞杆菌属,占鉴定细菌总数的53.62%,数量最少是气单胞菌属和嗜盐单胞菌属,均占鉴定细菌总数的2.90%.表明对虾肠道黏附菌群中具有较多能分泌多种消化酶的细菌,可进一步开发为促进对虾消化功能的益生菌  相似文献   

Effects of urbanization on stream hydrology and water quality: the Florida Gulf Coast     

R. Chelsea Nagy  B. Graeme Lockaby  Latif Kalin  Chris Anderson 《水文研究》2012,26(13):2019-2030

At the global scale, the population density of coastal areas is nearly three times that of inland areas, and consequently, land development represents a threat to coastal ecosystems. It is critical to understand how increasing urbanization affects coastal watersheds. To that end, the objective of this study was to examine the influence of urban development on stream water quality and hydrology in a coastal setting, a scenario that has received less attention than other physiographic regions. Stream hydrologic, physicochemical, and microbial data were collected in watersheds near Apalachicola, Florida with a range of impervious surfaces from 0 to 15%. Watersheds with greater impervious cover exhibited higher pH, specific conductance, and temperature, elevated nutrient concentrations and loads (, and total phosphorus), higher bacterial concentrations (fecal coliform and Escherichia coli), and increased maximum flow and hydrograph flashiness. Different responses to development here compared to other physiographic regions included lower total suspended solid concentrations, higher total dissolved solid concentrations, and a lack of response of base flow to increased urbanization. Additionally, Na⁺ and Cl^? concentrations were elevated to a greater extent than is often the case in non‐coastal areas. In the coming years, urban development is projected to increase substantially in coastal zones and thus there is risk of further stream degradation in coastal watersheds. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

黄海春季水华过程中微微型浮游生物的变化特点     

赵苑  赵丽  张武昌  刘诚刚  魏皓  肖天 《海洋与湖沼》2012,43(6):1030-1038

于2007年3—4月在黄海中部海域采用流式细胞术研究了春季水华过程中聚球藻、微微型真核浮游生物和异养细菌的生物量变化。聚球藻和微微真核型浮游生物的生物量与叶绿素a浓度变化基本呈现相反的趋势,在水华前期较高,水华期迅速下降,直至水华后期又有所升高。异养细菌在整个水华过程中变化较小,生物量在水华期最高,与水柱叶绿素a浓度呈极显著正相关(r=0.319,p<0.01)。水华期这三类微微型浮游生物对浮游植物总碳生物量的贡献很低。纤毛虫和鞭毛虫捕食可能是导致聚球藻和微微型真核浮游生物在水华期生物量降低的主要原因。  相似文献   

海洋细菌LP621 右旋糖苷酶分批发酵动力学研究     

葛亮  房耀维  吴文惠  王淑军  吕明生  焦豫良  刘姝 《海洋科学》2012,36(7):39-43

对海洋细菌Pseudoalteromonas tetraodonis LP621右旋糖苷酶进行了50L发酵罐分批发酵的代谢特性的研究.结果表明LP621右旋糖苷酶合成和菌体生长呈部分生长偶联型.据分批发酵试验结果采用Logistic方程、Luedeking-Piret方程建立了描述菌株生长、产酶以及葡萄糖底物消耗分批发酵动力学模型.动力学模型计算值结果与实验值拟合良好,较好反映了菌株右旋糖苷酶分批发酵过程的动力学特征.  相似文献   

环境因子对好氧不产氧光合细菌脂肪酸组成的影响     

邹丽洁  焦念志 《海洋科学》2012,36(9):9-16

对赤杆菌属(Erythrobacter)、柠檬酸微菌属(Citromicrobium)和玫瑰杆菌(Roseobacter)分支的9株好氧不产氧光合细菌(AAPB)的脂肪酸组成进行分析,并以10株非AAPB菌为参照,从脂肪酸角度考察光照、温度、营养等重要环境因子对AAPB的影响.结果显示, AAPB的脂肪酸以C18:1 w7c为主,该成分在Roseobacter分支中含量最高,不同种脂肪酸对环境因子的响应不同,低温和寡营养条件主要作用于不饱和脂肪酸(UFA);二羟基脂肪酸在寡营养和光照双重作用下有较明显的升高.此外,结合非AAPB 的比较也为 AAPB 脂肪酸研究提供了新的视角,如温度实验显示,由于不饱和脂肪酸的比例较高, AAPB 可能在寒冷海域有更好的竞争优势,而从饥饿培养试验来看, AAPB 的异养能力似乎比非AAPB更弱.  相似文献   

Influence of nitrate and dissolved organic carbon loading on the interaction of Microcystis aeruginosa and heterotrophic bacteria from hyper-eutrophic lake (Taihu Lake,China)     

《Limnologica》2015

To investigate the interaction between cyanobacteria and heterotrophic bacteria under gradients of glucose and nitrate, a cyanobacterial strain of Microcystis aeruginosa was grown in microcosms with and without a freshwater bacterial mixture, which was collected from Lake Taihu. Concentrations of glucose (1350, 975, 600, 300, 150, and 37.5 μmol C L⁻¹) and nitrate (150, 300, and 9000 μmol N L⁻¹) were used in a range of combinations giving 9 different treatments of glucose:nitrate. In the microcosm without the bacterial mixture, M. aeruginosa abundance gradually increased with days in all treatments. However, M. aeruginosa had much lower density in some treatments with the bacterial mixture. The difference in M. aeruginosa growth could be explained by competition with bacteria in the cultures in which these were added. The abundance of M. aeruginosa and bacteria when grown together was nearly equal and the number of the bacterial species was highest in the treatment with 300 μmol C L⁻¹ and 150 μmol N L⁻¹. Our results suggest that at this glucose:nitrate ratio M. aeruginosa and the bacterial mixture maintain a balance, and bacteria maintain diversity. In conclusion, we propose that dissolved organic carbon and nitrate availability fundamentally affects the structure as well as stoichiometry of pelagic associations.  相似文献   

氮素和水分添加对贝加尔针茅草原土壤氨氧化微生物群落结构的影响（英文）     

王杰  李刚  赖欣  宋晓龙  赵建宁  杨殿林 《资源与生态学报(英文版)》2015,6(1):1-11

应用PCR-DGGE技术研究了连续2年氮素、水分添加处理对贝加尔针茅草原土壤氨氧化细菌(AOB)16S r RNA基因和古菌(AOA)amo A基因遗传多样性的影响。结果表明,土壤硝化势在水分添加低氮(N30)和非水分添加高氮(N300)处理下较对照显著升高(P0.05),在水分添加高氮(N200、N300)处理下较对照急剧下降(P0.05)。不同处理下氨氧化细菌的群落结构变化较氨氧化古菌敏感,氮素添加显著改变了氨氧化微生物的群落结构,在高氮素处理下,氨氧化细菌的多样性指数有下降的趋势,而古菌的多样性则有升高的趋势,表明氨氧化古菌在高氮素下生长比较活跃。发育树分析的结果表明,非水分添加处理下,氨氧化细菌的群落由亚硝化螺菌属的Cluster 1、Cluster 3和Cluster 4组成,水分添加处理下由亚硝化螺菌属Cluster 3、Cluster 4和亚硝化单胞菌属的Cluster 6组成,而氨氧化古菌群落在水分添加处理下主要由泉古菌门的Cluster 1、Cluster 2和water lineage组成,在非水分添加处理下主要由泉古菌门的Cluster 1、Cluster 2和Cluster 5组成,两种水分输入机制下,氨氧化微生物群落的不同组成说明,水分在调节氨氧化微生物群落结构方面有重要作用。此外,氨氧化细菌群落多样性与全氮,NH4+和NO3-的含量呈显著负相关,而古菌群落与其呈显著正相关,说明氨氧化细菌与古菌对氮素和水分添加有不同的且互补的反应机制。  相似文献   

Simulation of the impacts of diagenesis or low-grade metamorphism on neutrophilic microaerobic Fe(II)-oxidizing biofilm     

LI Jun  LI YiLiang 《中国科学:地球科学(英文版)》2014,57(5):1021-1029

The microaerobic iron-oxidizing bacteria in circumneutral environment produce extracellular polymeric substances(EPS)with unique morphologic features,such as stalks or sheaths,which can be regarded as geobiological signatures.The Archean and early Palaeoproterozoic oceans were anoxic with high soluble Fe(II)that were suggested to have been oxidized through the metabolism of Fe(II)-oxidizing bacteria.The precursor of the ultrafine hematite in banded iron formation(BIF),e.g.,ferrihydrite,was suggested to be the mineral record of microbial Fe(II)-oxidation at that time.However,both the biological materials and primary iron minerals were prone to being altered by diagenetic or low-grade metamorphic processes.This makes it difficult to interpret the genesis of Precambrian BIFs.Here,we report experimental simulation on the effects of diagenesis or low-grade metamorphism on neutrophilic microaerobic Fe(II)-oxidizing bacteria and their biomass.Stalks,sheaths,and iron oxide spheroidal aggregates are partially preserved after the 100 MPa/300°C treatments,which indicates the mixed organic matters and iron oxides could survive the diagenetic or low-grade metamorphic processes.Some organic-mineral mixing structures carry information on microbial processes,though they appear similar to pseudomorphs of fossilized bacteria.  相似文献   

Effect of Chromium and Organic Acids on Microbial Growth and Exopolymeric Substance Production by Pseudomonas Bacteria          下载免费PDF全文

Nazime Mercan Dogan  Cetin Kantar  Goksel Dogan 《洁净——土壤、空气、水》2014,42(5):674-681

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Screening of PAH-degrading bacteria in a mangrove swamp using PCR-RFLP     

HuiJie Liu  CaiYun Yang  GuangHui Lin 《Marine pollution bulletin》2010,60(11):2056-2061

There are abundant PAH-degrading bacteria in mangrove sediments, and it is very important to screen the high efficiency degraders in order to perform bioremediation of PAH polluted environments. In order to obtain the more highly efficient PAH-degrading bacteria from a mangrove swamp, we first obtained 62 strains of PAH-degrading bacteria using traditional culture methods and based on their morphological characteristics. We then used the modern molecular biological technology of PCR-RFLP, in which the 16S rDNA of these strains were digested by different enzymes. Based on differences in the PCR-RFLP profiles, we obtained five strains of phenanthrene-degrading bacteria, five strains of pyrene-degrading bacteria, four strains of fluoranthene-degrading bacteria, five strains of benzo[a]pyrene-degrading bacteria and two strains of mixed PAH-degrading bacteria (including phenanthrene, pyrene, fluoranthene and benzo[a]pyrene). Finally, a total of 14 different PAH-degrading bacteria were obtained. The 16S rDNA sequences of these strains were aligned with the BLAST program on the NCBI website and it was found that they belonged to the α-proteobacteria and γ-proteobacteria, including four strains, where the similarities were no more than 97% and which were suspected therefore to be new species. This study indicated that PCR-RFLP was a very important method to screen degrading-bacteria, and also a significant molecular biological tool for the rapid classification and accurate identification of many different strains. On the other hand, it also showed that rich bacterial resources existed in mangrove areas, and that exploring and developing the functional microorganism from these mangrove areas would have wide use in the study of bioremediation of contaminated environments in the future.  相似文献