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111.
Ruggiero P Terzano R Spagnuolo M Cavalca L Colombo M Andreoni V Rao MA Perucci P Monaci E 《Journal of environmental monitoring : JEM》2011,13(1):145-156
Different soil samples characterised by a long-term Hg-pollution were studied for Hg total content, fractionation, phytotoxicity and influence on the bacterial community. Hg pollution ranged from 1 to 50 mg kg(-1) and most of it was speciated in scarcely soluble forms. In agreement with this, the biochemical quality indexes were investigated (biomass, enzyme activities) and the bacterial community (viable heterotrophic (VH) bacteria, functional diversity) apparently was not influenced by the degree of Hg pollution. In particular, the investigated soils exhibited a low percentage of Hg-resistant (Hg(R)) bacteria ranging from less than 0.001% to 0.25% of the VH and the addition of available Hg in the form of HgCl(2) induced an enrichment of resistant Hg(R) populations. The general biodiversity of the bacterial community was evaluated by denaturing gradient gel electrophoresis of DNA of Hg spiked soil microcosms and of control soils. Hg(R) bacteria capable to grow in a minimal medium containing HgCl(2) were also isolated and identified. MerA and merB gene PCR fragments were obtained from different Hg(R) strains and the range of similarities at the DNA level and at the deduced amino acid level showed that they carried mercuric reductase and lyase. Differently from bacteria, some influence of soil Hg content on seeds' germination and root elongation was observed for Lepidium sativum L. and Solanum lycopersicum L. In conclusion, most of the Hg in these long-term polluted soils was scarcely mobile and available and did not significantly influence the soil bacterial community. The risk of potential Hg remobilization over time, that could be naturally favoured by the activity of plant roots or other inorganic processes occurring in soil, can be extenuated since bacterial community was resistant and resilient to subsequent Hg stress. 相似文献
112.
高速铁路高填复合路堤边坡安全问题探讨 总被引:1,自引:0,他引:1
路基是高速铁路安全系统的关键和薄弱环节 ,建在软土上的高填路堤边坡是否稳定 ,更是直接关系到路基乃至整个高速铁路系统的安全 ,采用桩—网复合地基形式修建高路堤是一个好办法 ,这种路堤形式尚不多见。笔者结合其特点 ,从理论上提出了一种新的边坡安全实用计算方法 ;讨论了影响边坡安全的主要因素 ;验证了这一计算方法的合理性 相似文献
113.
Environmental, biological, socio-cultural and economic variations in the Himalayas have led to the evolution of diverse and unique traditional agroecosystems, crop species, and livestock, which help the traditional mountain farming societies to sustain themselves. During the recent past, as a result of rapid changes in land use caused by socio-cultural and economic changes and various environmental perturbations, the agrobiodiversity of the Central Himalayan agroecosystems has changed steadily. A recent survey conducted in 150 different villages located along an elevated transect of the Alaknanda catchment of the Central Himalaya revealed that over a period of two decades (1970–74 and 1990–94) the cultivated area under many traditional crops had declined significantly. A micro-level study carried out in 30 villages revealed that a series of changes had occurred in land use practices over a period of 25–30 years.The loss of agrobiodiversity and the changing socio-cultural and economic dimensions and their impacts on the sustainability of Himalayan agroecosystems are emerging as major causes of concern at local/regional/national scale, and appropriate options to meet these challenges are discussed in this paper. 相似文献
114.
Ravichandra P Mugeraya G Rao AG Ramakrishna M Jetty A 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(4):819-823
In the present study two strains of Thiobacillus sp were isolated from aerobic sludge of distillery and dairy effluent treatment plant using standard methods of isolation and enrichment. Experiments were conducted using isolated cultures in batch bioreactor with initial sulfide concentration of 75 and 150 mg/l. The effect of initial sulfide concentration on the activity of isolated Thiobacillus sp was studied. Sulfide oxidizing capacity was also determined at different initial sulfide concentrations. The results from the study indicate the possible isolation of Thiobacillus cultures from native source and application in the full-scale reactor 相似文献
115.
116.
细胞凋亡是调控机体发育和维护内环境稳定的重要机制。在克隆了稀有鮈鲫(Gobiocypris rarus)肝脏组织中凋亡相关的bcl-2、apaf-1、caspase-3和caspase-9基因的部分cDNA片段之后,进行了序列分析。结果表明,caspase-3和caspase-9基因片段与唐鱼(Tanichthys albonubes)相对应的核苷酸序列同源性最高,而bcl-2、apaf-1基因片段则分别与鮈鱼(Gobio gobio)和鲤鱼(Cyprinus carpio)相对应的核苷酸序列同源性最高,为99%和89%。基于稀有鮈鲫和已知物种的caspase-3基因核苷酸序列构建了系统发育树,发现稀有鮈鲫与唐鱼、斑马鱼(Danio rerio)的亲缘关系最近,而与金头鲷(Sparus aurata)、红鳍东方鲀(Takifugu rubripes)的亲缘关系较远。本研究为深入理解外源性化学物质对鱼类的毒理学机制及其生态健康风险评价提供科学数据,同时也为稀有鮈鲫在鲤科鱼类的分类及进化地位的研究提供分子水平的重要参考。 相似文献
117.
Aim of the present study was to synthesize titanium dioxide nanoparticles (YiO2 NPs) from marine actinobacteria and to develop an eco-friendly azo-dye degradation method. A total of five actinobacterial isolates were isolated from Chennai marine sediments, Tamilnadu, India and analyzed for the synthesis of TiO2 NPs using titanium hydroxide. Among these, the isolate PSV 3 showed positive results for the synthesis of TiO2 NPs, which was confirmed by UV analysis. Further characterization of the synthesized TiO2 NPs was done using XRD, AFM and FI'-IR analysis. Actinobacterial crude extract and synthesized TiO2 NPs was found efficient in degrading azo dye such as Acid Red 79 (AR-79) and Acid Red 80 (AR-80). Degradation percentage was found to be 81% for AR-79, 83% for AR-80 using actinobacterial crude extract and 84% for AR-79, 85% for AR-80 using TiO2 NPs. Immobilized actinobacterial ceils showed 88% for AR-79 and 81% for AR- 80, dye degrading capacity. Degraded components were characterized by FT-IR and GC-MS analysis. The phytotoxicity test with 500 μg/mL of untreated dye showed remarkable phenotypic as well as cellular damage to Tagetes erecta plant. Comparatively no such damage was observed on plants by degraded dye components. In biotoxicity assay, treated dyes showed less toxic effect as compared to the untreated dyes. 相似文献
118.
119.
"二噁英"是指具有相似化学结构和生物特征的一族化合物,分别属于三大类别:多氯代二苯并二噁英(PC-DDs),多氯代二苯并呋喃(PCDFs)以及多氯联苯(PCBs).PCDDs和PCDFs无商业目的性生产,而是在大量的人类活动中产生的.自然过程也可以产生PCDDs和PCDFs.在过去的十年里,环境立法机构和企业一起致力于减少二噁英的排放. 相似文献
120.
Summary This paper outlines the complexities and problems of animal husbandry in the Himalayas of India. In particular, the climatic influences of temperature, rainfall and humidity are emphasised. A wide range of possible improvements to decrease livestock malnutrition and mortality are proposed.Dr J.C. Biswas, BSc, MVSc, works in the Animal Genetics and Breeding Laboratory; Dr R. Somvanshi, MVSc, FRCVS (Sweden) is Veterinary Pathologist in charge of the Clinical Pathology and Medicine Section in Livestock Production Research and Lt.Col. Dr G.S.C. Ranga Rao, MVSc, is Veterinary Parasitologist and Joint Director. All three work at the Indian Veterinary Research Institute. 相似文献