1株高温异养硝化细菌的分离鉴定和特性研究

从高温堆肥中分离出1株高温异养硝化细菌。菌株经革兰氏染色为阴性,无荚膜,有芽孢的杆菌。根据形态、生理特征将该菌株初步鉴定为芽孢杆菌属(Bacillus spp),经研究发现该菌株以乙酰胺为唯一碳源和氮源时,能通过氨化和硝化作用产生亚硝酸。     

Microbial aspects of atrazine biodegradation in relation to history of soil treatment

Among 15 soils with different cropping practices, seven which had an history of repeated atrazine applications showed accelerated degradation of this herbicide. By contrast, grassland or agricultural soils with no recorded atrazine application, at least for the last three years, had a low degradation potential. No direct relation was found between the rate of atrazine mineralisation and the size of the microbial biomass. In adapted soils, the amounts of extractable residues were lowered and the very high percentages of radioactivity from [ring-¹⁴C]atrazine recovered as [¹⁴C]carbon dioxide demonstrated that N-dealkylation and deamidation were the only processes for micro-organisms to derive carbon and energy for heterotrophic growth. Kinetics of microbial ¹⁴C accumulation revealed that atrazine ring carbon could be incorporated by direct oxidative condensation with structural components of the bacterial or fungal cell whereas side-chain carbon was preferentially used for biosynthesis of new protoplasmic cell material, as confirmed by the high turnover rate of radiolabelled microbial components. From the determination of the Michaelis–Menten parameters, V_m and K_m in the presence of different selective biocides, it was possible to conclude that fungi were probably less active in atrazine degradation than bacteria and that over years the microbial atrazine-degrading community showed an increased efficiency. © 1999 Society of Chemical Industry     

马里亚纳海沟表层沉积物中微生物的群落组成和功能特征

深渊是迄今人类认识最少的海洋环境之一。深渊蕴含着丰富的微生物生物量，表现出活跃的有机碳周转特征，是深海有机碳降解的“热点”区域。然而，人类对深渊微生物的物种组成和代谢潜力还知之甚少。本文通过宏基因组技术与生物信息学分析，研究马里亚纳海沟“挑战者深渊”表层沉积物（水深10,853米）中的微生物群落组成和功能特征，揭示深渊表层沉积物中微生物驱动深海生物地球化学循环的潜在机制及其相应的生态效应。研究结果表明，变形菌门（Proteobacteria）、奇古菌门（Thaumarchaeota）、拟杆菌门（Bacteroidetes）、放线菌门（Actinobacteria）和浮霉菌门（Planctomycetes）是马里亚纳海沟表层沉积物中微生物的优势类群。表层沉积物中微生物的代谢分析表明其主要营异养代谢，可以降解多种有机物，包括一些难降解有机碳化合物（如邻苯二甲酸盐或其他芳香族化合物）。这些结果说明深渊沉积物中的微生物群落具有多样化的有机碳代谢能力，可以支持其开展活跃的有机碳降解过程。除了异养代谢过程，氨氧化等自养代谢过程在本研究的深渊微生物群落中也占据着重要地位，说明自养固碳可能是深渊表层沉积物中有机碳的重要来源。     

3种水质调控方式对参池底泥异养菌和弧菌数量的比较

为探究不同水质调控方式对海参养殖池塘（以下简称参池）底泥异养菌和弧菌数量的影响，该研究选择了三3类参池，分别是自然纳潮管理方式下的海参养殖池塘（以下简称自然池塘），配备微孔曝气增氧机的海参养殖池塘（以下简称微孔曝气池塘）和配备养水机设备的海参养殖池塘（以下简称养水机池塘），对参池底泥中异养菌和弧菌数量的周年变化进行检测。结果表明，各参池中底泥异养菌数量分别为：自然池塘94400~377625 cfu/g，微孔曝气池塘62633~247309 cfu/g，养水机池塘115037~273071 cfu/g，其中自然池塘1月最高，3月最低；微孔曝气池塘5月最高，6月最低；养水机池塘4月最高，8月最低。各参池中底泥弧菌数量分别为自然池塘0~3291 cfu/g，微孔曝气池塘35~5412 cfu/g，养水机池塘0~3037 cfu/g，各参池均呈“春季高，冬季低”的变化特征。弧菌与异养菌数比值在4、5月份相对较高，在2月份较低。通过实验初步比较不同水质调控方式对参池底质微生物数量的影响，为改善参池底质及探究微生物的变化提供理论依据。3种水质调控方式对参池底泥异养菌和弧菌数量的比较