Understanding the Development of Environmental Resistance Among Microbes: A Review          下载免费PDF全文

Jatin Srivastava  Harish Chandra  Nandita Singh  Swinder J. S. Kalra 《洁净——土壤、空气、水》2016,44(7):901-908

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饲料中添加益生菌对凡纳滨对虾(Litopenaeus vannamei)非特异免疫基因表达量和抗病力的影响   总被引：2，自引：0，他引：2  

孙艳  刘飞  宋晓玲  麦康森  李玉宏  黄倢 《海洋与湖沼》2012,43(4):845-851

采用实时荧光定量PCR方法,进行肠道复合益生菌对凡纳滨对虾相关免疫基因表达量的研究。通过感染实验,分析饲料中添加益生菌对凡纳滨对虾病毒感染能力的影响。结果表明,Real-time PCR揭示在投喂期间饲料中添加芽孢杆菌/溶藻弧菌组的对虾血淋巴细胞中的proPO、SOD和LZM的相对表达量均显著高于对照组(P<0.05);感染WSSV后,对芽孢杆菌/溶藻弧菌组凡纳滨对虾血淋巴7个采样时间点的proPO、SOD、LZM的表达进行Real-time PCR分析,检测表明WSSV刺激24h后,对虾血淋巴中的proPO、SOD和LZM的表达呈现显著性上调,且分别在48h、96h、96h达到最大值。累积死亡率结果证实饲料中添加益生菌均可提高其对虾抗WSSV感染的能力,尤其以坚强芽孢杆菌活菌与溶藻弧菌活菌配合使用效果更佳。  相似文献   

Seasonal patterns of benthic arthropods in a subtropical Andean basin     

Leticia M. Mesa  Hugo R. Fernández  María V. Manzo 《Limnologica》2009,39(2):152-162

We studied the seasonal variation of arthropod assemblages and the response to high discharge events in a subtropical Andean basin. Using abundance of common taxa and taxon richness of each sampled site, we examined the temporal variation of arthropods and related these changes with 12 environmental variables. Seasonal patterns of benthic arthropods were confirmed by uni- and multivariate techniques. Benthic abundance and taxon richness peaked on autumn-winter months, and declined abruptly on the month of peak discharge (summer season). Distinct taxonomic groups were dominant in each season influenced by discharge and seven chemical variables.Assemblage resistance to disturbance by spates was low. Rapid recovery of benthic arthropods after floods reflected high resilience of the system. The dominance of groups of short life cycles such as Ephemeroptera played an important role in this process.  相似文献   

The metabolic and fitness costs associated with metal resistance in Nereis diversicolor     

Chris Pook  Ceri Lewis  Tamara Galloway 《Marine pollution bulletin》2009,58(7):1063-1071

The population of Nereis diversicolor inhabiting the upper reaches of Restronguet Creek, Cornwall, UK is highly resistant to acute zinc and copper toxicity. Here we employ bioenergetic accounting and fecundity counts to demonstrate the energetic costs associated with this phenomenon in terms of the worms’ allocation of metabolic resources and reproductive output [P_r]. Metal-resistant animals exhibited a scope for growth that was 46-62% less than that of animals from two non-resistant reference populations, corresponding to a mean metabolic cost of 1.31 mJ h⁻¹ mg DW⁻¹. The resistant population also contained 13% less lipid than animals from the reference populations and 73-81% less carbohydrates. Consequently, mass-specific fecundity was reduced in resistant animals by 39-45%, although material investment in individual gametes did not appear to vary. This demonstrates fitness costs associated with metal resistance in this ecologically important polychaete and adds to our understanding of phenotypic trade-offs associated with resistance.  相似文献   

Flow-induced vegetation uprooting in a meandering bend:Experimental investigation     

Donatella Termini  Alice Di Leonardo 《国际泥沙研究》2022,37(3):399-410

Vegetation uprooting is a complex process which depends on many interrelated factors. In this paper,attention is focused on the flow-induced uprooting in river bends, where the flow characteristics vary as effected by the channel’s curvature and its continuous changing in the downstream direction. Results are presented by an experimental work done in a high-amplitude meandering flume with mature herbaceous vegetation on the bed. In the first part of the paper, the variation along the bend of the...  相似文献   

“The sea is our bread”: Interrupting green neoliberalism in Mexico     

《Marine Policy》2017

This article analyzes how the intensification of neoliberal policies and the use of privatization to govern access to the ocean and its resources are producing the conditions for the dispossession of Indigenous fishing customary rights as well as resistance practices that interrupt neoliberal policies. This article highlights the role of actors beyond the state in producing the specific junctures at which the vocation of the Indigenous peoples in the Tehuantepec Isthmus in the state of Oaxaca, Mexico, is changed to become a “center of sustainable development.”  相似文献   

基于电容率法的矿藏勘探新方法研究     

刘红岐  邓友明  夏宏泉  邱春宁  刘诗琼  唐洪  蒋成思 《地球科学进展》2009,24(9):1051-1056

重点介绍了NaC l溶液的电容随着溶液矿化度、测量极板之间的距离以及测量频率的变化规律。结果表明,在直接测量电容的情况下,NaC l溶液的电容随着极板距离的增加按负平方关系减小;随着溶液浓度的增加按平方关系增加;随着频率的增加按负幂指数规律减小。通过和NaC l溶液电阻的对比发现,同样的条件下,电容的变化率比电阻明显,这将有助于地层流体的识别,尤其是目前大量存在的水淹油气层、低阻油气层和薄油层。基于以上结论,提出了第二介电常数的概念,第二介电常数不同于传统介电常数的关键之处在于:第二介电常数是直接测量介质的介电特性,而不是将其置于极板之间进行测量。还指出,在进行交流电测井时,地层的电容信号也同样能反映出地层及其孔隙流体的特征,在此基础上提出了电容率法测井的想法,即在测量地层电阻率的同时,还要进行电容率的测量,来反映地层及其孔隙流体电容率的信息。此外,还提出了两电极法进行地面电容率勘探的设想,这种方法不仅能够用于找油找气,还可以探测金属矿藏。  相似文献   

Wind Profile Diagnosis from Surface Routine Meteorological Data Over a Coastal Area     

Maria Tombrou  Dimitra Founda 《Boundary-Layer Meteorology》1998,87(2):217-231

A simple algorithm is proposed in order to transform routine surface wind speed observations near the coast to a wind at the height of the equilibrium planetary boundary layer as well as to any other height over a relatively flat coastal region. The model is based on the well known internal boundary layer (IBL) concept, Monin-Obukhov similarity theory and the resistance law, and describes the effects of the roughness transition from sea to land as well as the effect of stability on the shape of the profiles and the IBL growth. The required input weather data are no more than surface wind speed, air temperature and total cloud cover. Satisfactory agreement was found between measurements at Hellinikon airport and estimations made with the scheme. The introduction of a transition layer above the IBL did not improve the agreement to any significant extent. Mean values of the estimated wind differed by less than 1 m s ^-1 from the observed ones, a difference within the accuracy of the reported rawinsonde values. The rms error varied in the range of 17–22% of the observed average value, giving the best agreement under unstable conditions. The correlation coefficient between the observed and the estimated values of the wind, at the height of the equilibrium planetary boundary layer, ranged between 0.74 and 0.90.  相似文献   

“Twenty years is yesterday”: Science, multinational mining, and the political ecology of trust in New Caledonia     

Leah S. Horowitz 《Geoforum》2010,41(4):617-626

To date, the scholarly literature has insufficiently investigated the micropolitical ecology of trust, the ways that different interests and expectations within a community can differentially mediate trust relationships between members of that community and an exogenous institution. This study explores the complexities of, and intra-community disagreements about, Kanak villagers’ decisions about whether to trust information provided by, or seemingly in support of, a multinational mining project in southern New Caledonia (South Pacific). An indigenous protest group challenged the company’s claims that the construction and operation of a refinery would have no harmful effects on local ecosystems. The company construed this opposition as stemming from fear based in ignorance, to which the solution lay in the provision of technical information. However, villagers disagreed as to whether this information was reliable. Meanwhile, many project employees joined the protest group. I argue that this seeming irony may be explained by examining the role of affiliation - defined here as a sense of solidarity with a group, and the desire to maintain that relationship - in establishing trust. Culturally-informed expectations of long-term social relationships and the reciprocal power these entailed, and concerns about long-term economic security, played a large role in determining which affiliations people chose to privilege, which in turn influenced which “scientific” information they chose to trust. Ultimately, I argue for the usefulness of a deeper understanding of relationships between trust, affiliation, and expectations of long-term social and economic relations in analyzing lay persons’ evaluations of science.  相似文献   

What is social sustainability? A clarification of concepts     

Suzanne Vallance  Harvey C. Perkins 《Geoforum》2011,42(3):342-348

Though the concept of sustainable development originally included a clear social mandate, for two decades this human dimension has been neglected amidst abbreviated references to sustainability that have focused on bio-physical environmental issues, or been subsumed within a discourse that conflated ‘development’ and ‘economic growth’. The widespread failure of this approach to generate meaningful change has led to renewed interest in the concept of ‘social sustainability’ and aspects thereof. A review of the literature suggests, however, that it is a concept in chaos, and we argue that this severely compromises its importance and utility. The purpose of this paper is to examine this diverse literature so as to clarify what might be meant by the term social sustainability and highlight different ways in which it contributes to sustainable development more generally. We present a threefold schema comprising: (a) ‘development sustainability’ addressing basic needs, the creation of social capital, justice and so on; (b) ‘bridge sustainability’ concerning changes in behaviour so as to achieve bio-physical environmental goals and; (c) ‘maintenance sustainability’ referring to the preservation - or what can be sustained - of socio-cultural characteristics in the face of change, and the ways in which people actively embrace or resist those changes. We use this tripartite of social sustainabilities to explore ways in which contradictions and complements between them impede or promote sustainable development, and draw upon housing in urban areas as a means of explicating these ideas.  相似文献