东太平洋海洋微生物种群多样性初步研究   总被引：3，自引：0，他引：3  

李明  叶德赞  黄翔玲 《海洋湖沼通报》2008,(2):75-81

以东太平洋海洋微生物群落为研究对象,用稀释平板分离法,从海水中分离得到67株细菌。在形态观察的基础上选取48株进行培养,然后进行16S rDNA基因扩增,并用限制性内切酶RsaI和MspI对PCR产物进行ARDRA(Amplified rDNA restriction analysis)多态性分析,共得到10种不同的操作分类单元(Operational Taxonomic Unit,OTU)。其中OTU4和OTU10所包含的菌株分别占总分离物的35.4%和18.8%,为优势分离菌。优势分离菌的ERIC-PCR基因组指纹图分析表明,前者的17株分离物共有10种不同的指纹图类型,而后者的9株分离物有3种。结果显示,东太平洋海域的海水和底质沉积物具有明显的微生物种群多样性特征。  相似文献   

Combined effects of heavy metal and polycyclic aromatic hydrocarbon on soil microorganism communities   总被引：2，自引：0，他引：2  

Linkui Cao  Guoqing Shen  Yitong Lu 《Environmental Geology》2008,54(7):1531-1536

Soil contaminated sites contain a variety of pollutants, especially heavy metals and polycyclic aromatic hydrocarbons (PAHs). Interactions between heavy metals have been relatively well studied, but little is known about interactions between heavy metals and PAHs. The combined effect of heavy metals and PAHs on soil microorganism was studied in laboratory conditions and evaluated by random denaturing gradient gel electrophoresis. We extracted DNA directly from contaminated soils and then amplified the V3 sequences of the 16S rDNA. The results showed that with different culture time, the gene diversity of the single and combined contaminated soil differed as well. After 15 days of culture, the microorganisms were stimulated and accommodated. After 45 days of cultivation, the quantities of the soil microorganisms were affected. It is concluded that some of the microorganisms utilize phenanthrene as important carbon resources. Microorganisms directly isolated from soil could reflect the diversity of soil microorganism and population distribution conditions.  相似文献   

鲍类微生物性疾病研究进展   总被引：4，自引：0，他引：4  

王瑞旋  徐力文  冯娟  王江勇 《海洋湖沼通报》2006,90(2):117-124

鲍类微生物性病害包括病毒性疾病、原核生物样疾病、细菌性疾病及真菌性疾病。本文就鲍类微生物病害的病原学、致病机制、组织病理学和流行病学等方面的进展,以及相关的诊断防治研究情况进行概述,以期为今后鲍类的病害防治研究提供依据。  相似文献   

海洋微生物活性物质的研究进展   总被引：2，自引：0，他引：2  

刘晶晶  陈全震  曾江宁  高爱根  廖一波 《海洋学研究》2007,25(1):55-65

海洋微生物由于其特殊的生存环境,往往能产生结构新颖、功能多样的活性物质,海洋微生物作为活性物质的新来源,正日益受到人们的关注。综述了近几年海洋微生物产生的抗肿瘤、抗心血管病、免疫调节剂、抗生素等生物活性物质的开发利用现状及相关的研究技术和方法,展示出海洋微生物活性物质巨大的开发利用前景。  相似文献   

A Study in Ultra-Ecology: Microorganisms on the Seagrass Posidonia oceanica (L.) DELILE     

Rudolf  Novak 《Marine Ecology》1984,5(2):143-190

Abstract. Microbial colonization on the leaves of a shoot of the mediterranean seagrass Posidonia oceanica (L.) DELILE was studied using Scanning Electron Microscopy. Methods of field ecology such as transect, random plot and stratified sampling survey were applied to the microbial niveau to gain both qualitative and quantitative information on the microbial assemblage. While macro-epiphytic growth was significantly greater on the outer leaf sides, microbial colonization density was significantly higher on the inner leaf sides, both on leaf surface and epiphyte surface. Diatoms colonized the surface of incrusting algae and epiphytic animals in significantly lower numbers than the Posidonia leaf surface and were absent on erect epiphytic algae. Bacterial densities on epiphyte surfaces even exceeded values of the corresponding leaf surfaces on algal thalli near the leaf tips and on old leaves. Diatoms reach highest mean density on mature leaves and close to the leaf tips, while bacteria reach their greatest density on the oldest leaf and closer to the leaf base. Diatom density in general increases with exposure time of plant surface, while greatest bacterial density was observed at 7–10 weeks exposure. Basal leaf parts on younger leaves were dominated by rod-shaped bacteria, while distal leaf parts and old leaves were dominated by small coccoid bacteria. Surfaces of epiphytic algae were always distinctly dominated by small coccoid bacteria, and edges of thalli attracted high microbial densities. Microbial biomass (calculated from cell volumes using standard conversion factors) amounts to 2.3 g dry weight m-² in the Posidonia stand where the shoot was sampled. The observed patterns of epiphytic colonization are interpreted as the result of a complex, dynamically changing system of interactions both within the epiphytic community and between the epiphytic community, the host plant, and it's environment. A model of the organization of the epiphytic community on Posidonia leaves is presented. “Ultra-ecology” is a term introduced to denote a type of SEM research in the micro-environment which is analogous to in situ investigation in “macroscopic” ecological work.  相似文献   

羟基对赤潮生物的光合色素作用实验     

白希尧  白敏菂  杨波  张芝涛 《海洋科学》2006,30(11):5-8

羟基药剂具有氧化力极强、杀灭微生物的生化反应速度极快的特性。在容积1.8m3的水槽里进行了羟基对微藻的光合色素影响的中宇宙规模实验。羟基质量浓度达到0.55mg/L时,微生物的叶绿素a、b含量均低于检测方法的最低限值,其衰减率为100%,类胡萝卜素衰减率为92.3%,脱镁叶绿素增加了15.05倍。实验数据表明,羟基药剂将是治理赤潮的绿色有效方法。  相似文献   

Seasonal distribution of bacteria in salt marsh sediments in North Carolina     

Parke A. Rublee 《Estuarine, Coastal and Shelf Science》1982,15(1):67-74

The number and size of bacteria at four depths (0–1, 5–6, 10–11 and 20–21 cm) in a North Carolina salt marsh were minotored by direct counts for 13 months. The number of bacteria reached a maximum of about 1·4 × 10¹⁰ cells cm^?3 at the sediment surface in October, corresponding to the period of Spartina alterniflora die-back. Cell numbers were lowest and most consistent throughout the year at the 20 cm depth of sediment. Cell volumes averaged 0·2 μm³ at the marsh surface and decreased with depth. Mean standing crop of bacteria to a depth of 20 cm of sediment was about 14 g bacterial carbon m^?2. In surface sediments bacteria contribute up to 15% and algae up to 10% of total living microbial biomass as estimated by adenosine triphosphate (ATP). Bacteria were the major biomass component at sediment depths of 5, 10 and 20 cm. At all depths the microbial community contributes < 4% total organic carbon and < 8% of total nitrogen.  相似文献   

Degradation Kinetics of Petroleum Contaminants in Soft-Water Systems     

ZHENGXilai WANGBingchen LIYuying XIAWenxiang 《《地质学报》英文版》2004,78(3):825-828

On the basis of site investigation and sample collection of petroleum contaminants in the soil-water-crop system in the Shenyang-Fushun sewage irrigation area, the physical-chemical-biological compositions of the unsaturated zone is analyzed systematically in this paper. At the same time, the degradation kinetics of residual and aqueous oils is determined through biodegradation tests. The studies show that dominant microorganisms have been formed in the soils after long-term sewage irrigation. The microorganisms mainly include bacteria, and a few of fungus and actinomycetes.After a 110-days‘ biodegradation test, the degradation rate of residual oil is 9.74%--10.63%, while the degradation rate of aqueous oil reaches 62.43 %. This indicates that the degradation rate of low-carbon aqueous oil is higher than that of highcarbon residual oil. In addition, although microbial degradation of petroleum contaminants in soils is suitable to the firstorder kinetics equation, the half-lives of aqueous oil, No. 20 heavy diesel and residual oil in the surface soils (L2-1, S1-1 and X1-1) are 1732 h, 3465 h and 17325 h, respectively.  相似文献   

Ancient wet aeolian environments on Earth: clues to presence of fossil/live microorganisms on Mars     

William C Mahaney  Michael W Milner  David Malloch  Victor R Baker  Trent M Hare 《Icarus》2004,171(1):39-53

Ancient wet aeolian (wet-sabkha) environments on Earth, represented in the Entrada and Navajo sandstones of Utah, contain pipe structures considered to be the product of gas/water release under pressure. The sediments originally had considerable porosity allowing the ingress of living plant structures, microorganisms, clay minerals, and fine-grained primary minerals of silt and sand size from the surface downward in the sedimentary column. Host rock material is of a similar size and porosity and presumably the downward migration of fine-grained material would have been possible prior to lithogenesis and final cementation. Recent field emission scanning electron microscopy (FESEM) and EDS (energy-dispersive spectrometry) examination of sands from fluidized pipes in the Early Jurassic Navajo Sandstone reveal the presence of fossil forms resembling fungal filaments, some bearing hyphopodium-like structures similar to those produced by modern tropical leaf parasites. The tropical origin of the fungi is consistent with the paleogeography of the sandstone, which was deposited in a tropical arid environment. These fossil fungi are silicized, with minor amounts of CaCO₃ and Fe, and in some cases a Si/Al ratio similar to smectite. They exist as pseudomorphs, totally depleted in nitrogen, adhering to the surfaces of fine-grained sands, principally quartz and orthoclase. Similar wet aeolian paleoenvironments are suspected for Mars, especially following catastrophic sediment-charged floods of enormous magnitudes that are believed to have contributed to rapid formation of large water bodies in the northern plains, ranging from lakes to oceans. These events are suspected to have contributed to a high frequency of constructional landforms (also known as pseudocraters) related to trapped volatiles and water-enriched sediment underneath a thick blanket of materials that were subsequently released to the martian surface, forming piping structures at the near surface and constructional landforms at the surface. This constructional process on Mars may help unravel the complex history of some of the piping structures observed on Earth; on Earth, evidence for the constructional landforms has been all but erased and the near-surface piping structures exposed through millions of years of differential erosion and topographic inversion now occur as high-standing promontories. If the features on both Earth and Mars formed by similar processes, especially involving water and other volatiles, and since the piping structures of Earth provided suitable environments for life to thrive in, the martian features in the northern plains should be considered as prime targets for physico/mineral/chemical/microbiological analyses once the astrobiological exploration of the red planet begins in earnest.  相似文献   

Desert Potholes: Ephemeral Aquatic Microsystems   总被引：1，自引：0，他引：1  

Marjorie?A.?ChanEmail author  Katrina?Moser  Jim?M.?Davis  Gordon?Southam  Kebbi?Hughes  Tim?Graham 《Aquatic Geochemistry》2005,11(3):279-302

An enigma of the Colorado Plateau high desert is the “pothole”, which ranges from shallow ephemeral puddles to deeply carved pools. The existence of prokaryotic to eukaryotic organisms within these pools is largely controlled by the presence of collected rainwater. Multivariate statistical analysis of physical and chemical limnologic data variables measured from potholes indicates spatial and temporal variations, particularly in water depth, manganese, iron, nitrate and sulfate concentrations and salinity. Variation in water depth and salinity are likely related to the amount of time since the last precipitation, whereas the other variables may be related to redox potential. The spatial and temporal variations in water chemistry affect the distribution of organisms, which must adapt to daily and seasonal extremes of fluctuating temperature (0–60 °C), pH changes of as much as 5 units over 12 days, and desiccation. For example, many species become dormant when potholes dry, in order to endure intense heat, UV radiation, desiccation and freezing, only to flourish again upon rehydration. But the pothole organisms also have a profound impact on the potholes. Through photosynthesis and respiration, pothole organisms affect redox potential, and indirectly alter the water chemistry. Laboratory examination of dried biofilm from the potholes revealed that within 2 weeks of hydration, the surface of the desiccated, black biofilm became green from cyanobacterial growth, which supported significant growth in heterotrophic bacterial populations. This complex biofilm is persumably responsible for dissolving the cement between the sandstone grains, allowing the potholes to enlarge, and for sealing the potholes, enabling them to retain water longer than the surrounding sandstone. Despite the remarkable ability of life in potholes to persist, desert potholes may be extremely sensitive to anthropogenic effects. The unique limnology and ecology of Utah potholes holds great scientific value for understanding water–rock–biological interactions with possible applications to life on other planetary bodies.  相似文献