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1.
目的:为阐明微生物群落演替及功能与浸出效率之间关系奠定基础,以及如何提高黄铜矿生物浸出效率和铜回收率提供理 论依据。方法:通过连续传代培养进行驯化,使得复合菌群的矿浆浓度耐受能力达到25 %(w/v)。采用该复合菌群在25 %矿浆浓 度下浸出黄铜矿,同时利用变性梯度凝胶电泳和克隆文库技术分析浸出过程中的微生物多样性。最后,采用实时荧光定量PCR 对 浸出过程中微生物群落结构进行定量解析。结果:28天内黄铜矿浸出率能够达到95.1 %,而驯化前的浸出率只有51.5%。该复合 菌群主要由Acidithiobacillus caldus, Sulfobacillus acidophilus,和Fereoplasma theroplasma thermophilum组成,其中Acidithbacillus caldus是浸出前期和后期的优势种群,而Sulfobacillus acidophilus在浸出中期均有竞争优势, Ferroplasma thermophilum在整个浸出过程中占 据整个群落的比例均较低。结论:本研究获得的复合菌群具有较强的浸出黄铜矿能力, Acidithiobacillus caldus和Sulfobacillus acidophilus在浸出过程中起着重要的作用,pH 值和铜浸出率与群落结构相关性较高。  相似文献   
2.

Background

Host-microbe and microbe-microbe interactions are often governed by the complex exchange of metabolites. Such interactions play a key role in determining the way pathogenic and commensal species impact their host and in the assembly of complex microbial communities. Recently, several studies have demonstrated how such interactions are reflected in the organization of the metabolic networks of the interacting species, and introduced various graph theory-based methods to predict host-microbe and microbe-microbe interactions directly from network topology. Using these methods, such studies have revealed evolutionary and ecological processes that shape species interactions and community assembly, highlighting the potential of this reverse-ecology research paradigm.

Results

NetCooperate is a web-based tool and a software package for determining host-microbe and microbe-microbe cooperative potential. It specifically calculates two previously developed and validated metrics for species interaction: the Biosynthetic Support Score which quantifies the ability of a host species to supply the nutritional requirements of a parasitic or a commensal species, and the Metabolic Complementarity Index which quantifies the complementarity of a pair of microbial organisms’ niches. NetCooperate takes as input a pair of metabolic networks, and returns the pairwise metrics as well as a list of potential syntrophic metabolic compounds.

Conclusions

The Biosynthetic Support Score and Metabolic Complementarity Index provide insight into host-microbe and microbe-microbe metabolic interactions. NetCooperate determines these interaction indices from metabolic network topology, and can be used for small- or large-scale analyses. NetCooperate is provided as both a web-based tool and an open-source Python module; both are freely available online at http://elbo.gs.washington.edu/software_netcooperate.html.  相似文献   
3.
In the study of food webs, the existence and explanation of recurring patterns, such as the scale invariance of linkage density, predator–prey ratios and mean chain length, constitute long-standing issues. Our study focused on litter-associated food webs and explored the influence of detritivore and predator niche width (as δ13C range) on web topological structure. To compare patterns within and between aquatic and terrestrial ecosystems and take account of intra-habitat variability, we constructed 42 macroinvertebrate patch-scale webs in four different habitats (lake, lagoon, beech forest and cornfield), using an experimental approach with litterbags. The results suggest that although web differences exist between ecosystems, patterns are more similar within than between aquatic and terrestrial web types. In accordance with optimal foraging theory, we found that the niche width of predators and prey increased with the number of predators and prey taxa as a proportion of total taxa in the community. The tendency was more marked in terrestrial ecosystems and can be explained by a lower per capita food level than in aquatic ecosystems, particularly evident for predators. In accordance with these results, the number of links increased with the number of species but with a significantly sharper regression slope for terrestrial ecosystems. As a consequence, linkage density, which was found to be directly correlated to niche width, increased with the total number of species in terrestrial webs, whereas it did not change significantly in aquatic ones, where connectance scaled negatively with the total number of species. In both types of ecosystem, web robustness to rare species removal increased with connectance and the niche width of predators. In conclusion, although limited to litter-associated macroinvertebrate assemblages, this study highlights structural differences and similarities between aquatic and terrestrial detrital webs, providing field evidence of the central role of niche width in determining the structure of detritus-based food webs and posing foraging optimisation constraints as a general mechanistic explanation of food web complexity differences within and between ecosystem types.  相似文献   
4.
In the Chihuahuan Desert of the southwestern United States we monitored responses of both winter and summer annual plant communities to natural environmental variation and to experimental removal of seed-eating rodents and ants for 13 years. Analyses of data on population densities of the species by principal component analysis (PCA) followed by repeated measures analysis of variance (rmANOVA) on PCA scores showed that: (1) composition of both winter and summer annual communities varied substantially from year to year, presumably in response to interannual climatic variation, and (2) community composition of winter annuals was also significantly affected by the experimental manipulations of seed-eating animals, but the composition of the summer annual community showed no significant response to these experimental treatments. Canonical discriminant analysis (CDA) was then applied to the data for winter annuals to more clearly identify the responses to the different classes of experimental manipulations. This analysis showed that removing rodents or ants or both taxa caused distinctive changes in species composition. There was a tendency for large-seeded species to increase on rodent removal plots and to decrease on ant removal plots, and for small-seeded species to change in the opposite direction. In the winter annual community there was a significant time x treatment interaction: certain combinations of species that responded differently to removal of granivores also showed opposite fluctuations in response to long-term climatic variation. The large year-to-year variation in the summer annual community was closely and positively correlated across all experimental treatments. The use of multivariate analysis in conjunction with long-term monitoring and experimental manipulation shows how biotic interactions interact with variation in abiotic conditions to affect community dynamics.  相似文献   
5.
The politics of active ageing present active citizenship of the elderly as a key challenge for the coming years. Active citizenship has been defined in different ways (as complimentary in most cases), outlining an eclecticism of participatory activities that includes political engagement in a participatory and deliberative manner, as well as community and voluntary action. This term is found in different contexts such as formal politics, work, civil society, and the home. This paper, based on a systematic review, identifies the context in which this concept emerges in relation to older people and people with dementia. It also analyses the different expressions of active citizenship used, and provides key elements to be taken into account in the formulation of policies in a context of accelerated demographic ageing and where dementia is a public health priority. The notion of active citizenship in old age is a step forward from active ageing to a broader concept that integrates the principle of equality between people irrespective of gender, age and the need for support.  相似文献   
6.
As a process affecting animal communities, urbanization has been the subject of numerous studies. However, amphibians are still among the least studied vertebrate groups in urbanized landscapes. Generally, it has been found that the process of loss of amphibian diversity is nonrandom, with species from older evolutionary lines at greater risk. Regional data on amphibian assemblages in urban areas is a very useful tool for assessing how these assemblages react to changes.The aim of the present paper is to assess the diversity of amphibians in Polish cities based on data in the relevant literature, exploring different metrics (e.g., taxonomic, functional, and evolutionary diversity) calculated in amphibian species assemblages. We used data from 18 articles (including grey literature), characterized by comparable research methods and published between 1999 and 2017.Overall, amphibian species richness (ASR) amounted to an average of 9 species, ranging from 5 to 11 species per city. The higher species richness occurred in Białystok in North-west of Poland. Functional evenness (FEve), evolutionary distinctiveness (ED sum), and functional richness (FRic) were strongly positively correlated with ASR. However, ED mean was not significantly correlated with the total number of species in the community. Three taxa, the hybridogenetic water frogs Pelophylax esculentus complex, the common toad Bufo bufo, and the common frog Rana temporaria, occurred in all analyzed amphibian assemblages. Our study is one of the first attempts to compare urban amphibian assemblages, using different and complementary diversity metrics on a large spatial scale. In conclusion, we highlight that urban areas play an important role for conservation of amphibians, because they support amphibian assemblages characterized by a high level of overall diversity.  相似文献   
7.
【目的】了解大水面放养水葫芦对富营养化湖泊水体可培养细菌群落结构和多样性的影响。【方法】采用稀释平板法,分别对云南滇池紫根水葫芦放养区(ZW)、野生型普通水葫芦放养区(PW)、未放养水葫芦对照区(CK)水体中细菌进行分离,并对其16S r RNA序列进行分析。【结果】分别从ZW、PW、CK 3种水体分离得到54、49、40株菌落形态差异的细菌,Shannon-Wiener多样性指数分别为3.17、3.07、2.73,细菌数量分别为1.35×107、8.35×106、2.70×106 CFU/L。16S r RNA序列分析表明,ZW、PW、CK 3种水体可培养细菌主要包括变形菌门α亚群(Alphaproteobacteria,35.1%、32.4%和40%)、放线菌门(Actinobacteria,18.9%、32.4%和20%)、变形菌门β亚群(Betaproteobacteria,13.5%、5.9%和16.0%)、变形菌门γ亚群(Gammaproteobacteria,13.5%、14.6%和12.0%)、拟杆菌门(Bacteroidetes,13.5%、8.8%和8.0%)和厚壁菌门(Firmicutes,2.7%、5.9%和4.0%)。在属的水平上,3种水体仅有鞘氨醇盒菌属(Sphingopyxis)、红细菌属(Rhodobacter)、黄色杆菌属(Xanthobacter)、新鞘脂菌属(Novosphingobium)、鞘氨醇单胞菌属(Sphingomonas)、假单胞菌属(Pseudomonas)、微杆菌属(Microbacterium)、链霉菌属(Steptomyces)、黄杆菌属(Flavobacterium)、芽孢杆菌属(Bacillus)等10个属的细菌为共有菌属。【结论】大水面放养水葫芦提高了富营养化湖泊水体中可培养细菌的多样性,改变了细菌的群落结构。  相似文献   
8.
橘小实蝇成虫肠道可培养细菌群落结构分析   总被引:1,自引:0,他引:1  
【目的】研究橘小实蝇(Bactrocera dorsalis) 3个种群(实验室正常喂养种群、实验室无菌糖水喂养种群和野生种群)成虫肠道可培养细菌的群落结构组成。【方法】利用16S rRNA基因的聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)分析技术,结合菌落形态观察和生理生化特征鉴定细菌种类。【结果】从橘小实蝇3个种群成虫肠道600株可培养细菌得到53种不同细菌遗传型,分属于肠杆菌科(Enterobacteriaceae)、肠球菌科(Enterococcaceae)和芽孢杆菌科(Bacillaceae)等3个科。其中肠杆菌科是肠道可培养细菌最优势的细菌种类。同样以序列相似性大于97%的菌株归为相同的细菌种类为标准,找到了橘小实蝇3个种群可培养细菌的共有菌种,结合菌落形态观察和生理生化特征鉴定,确定共有菌种为肠杆菌属5株,克雷伯氏菌属2株,柠檬酸杆菌属1株,泛菌属1株,肠球菌属2株,以及芽孢杆菌属4株。【结论】通过研究橘小实蝇成虫肠道可培养细菌群落结构组成,可为探讨肠道菌群对寄主的生理功能和生态学意义奠定基础,最终为利用微生物防治此类害虫提供新思路。  相似文献   
9.
Universal taxonomic frameworks have been critical tools to structure the fields of botany, zoology, mycology, and bacteriology as well as their large research communities. Animals, plants, and fungi have relatively solid, stable morpho‐taxonomies built over the last three centuries, while bacteria have been classified for the last three decades under a coherent molecular taxonomic framework. By contrast, no such common language exists for microbial eukaryotes, even though environmental ‘‐omics’ surveys suggest that protists make up most of the organismal and genetic complexity of our planet's ecosystems! With the current deluge of eukaryotic meta‐omics data, we urgently need to build up a universal eukaryotic taxonomy bridging the protist ‐omics age to the fragile, centuries‐old body of classical knowledge that has effectively linked protist taxa to morphological, physiological, and ecological information. UniEuk is an open, inclusive, community‐based and expert‐driven international initiative to build a flexible, adaptive universal taxonomic framework for eukaryotes. It unites three complementary modules, EukRef, EukBank, and EukMap, which use phylogenetic markers, environmental metabarcoding surveys, and expert knowledge to inform the taxonomic framework. The UniEuk taxonomy is directly implemented in the European Nucleotide Archive at EMBL‐EBI, ensuring its broad use and long‐term preservation as a reference taxonomy for eukaryotes.  相似文献   
10.
横山水库浮游动物群落结构特征及水质评价   总被引:6,自引:0,他引:6  
为了解横山水库浮游动物群落结构特征及水质状况,于2012年5月(春)、7月(夏)、10月(秋)及2013年1月(冬)对该水库的浮游动物及主要水质理化指标进行了调查分析,利用生物多样性指数法和综合营养状态指数法评价其水质状况。结果共鉴定浮游动物100种(原生动物47种、轮虫36种、枝角类12种、桡足类5种)。春夏秋季种类组成主要以轮虫和原生动物为主,枝角类与桡足类种类较少;冬季各种类均很少。优势种为王氏似铃壳虫(Tintinnopsis wangi)、淡水简筒虫(Tintinnidium fluviatile)、球形沙壳虫(Difflugia globulosa)、湖生累枝虫(Epistylis lacustris)、裂痕龟纹轮虫(Anuraeopsis fissa)、针簇多肢轮虫(Polyarthra trigla)、裂足臂尾轮虫(Brachionus diversicornis)和等刺异尾轮虫(Trichocerca similis),季节更替明显。浮游动物年均丰度为1460 ind./L,变化范围17—3164 ind./L;年均生物量为1.252 mg/L,变化范围0.042—2.732 mg/L;香农多样性指数(H')、均匀度指数(J)及丰富度指数(D)年均值分别为2.06、0.68及1.30;全年综合营养状态指数值范围33.36—44.15。CCA分析表明,温度及pH等环境因子与浮游动物群落结构具有明显相关性。水质总体评价显示,横山水库水质处中污染状态、水体处中营养水平,基本符合国家Ⅱ类水的水质标准,但作为饮用水水源地,其水质还需进一步加强管理与调控。  相似文献   
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