Olaquindox resistance in the coliform flora of pigs and their environment: an ecological study

Faecal samples were taken weekly from a chosen pen on each of four commercial pig farms, two of which used olaquindox as a feed additive. Coliform bacteria were isolated from the samples and the incidence and level of resistance to olaquindox and to four therapeutic antibiotics determined. The coliforms isolated were biotyped to follow the emergence of drug-resistant sub-populations. The results showed that the coliform flora was complex and that a turnover of biotypes was associated with changes in the occupancy of the pen and, possibly, diet. This turnover led to large fluctuations in both incidence and level of resistance to olaquindox and the antibiotics. Olaquindox resistance was not specifically linked with resistance to any therapeutic antibiotic, and the possible origin of olaquindox-resistant strains is discussed in relation to the biotypes.     

On organism: environment buffers and their ecological significance

We consider, from a physical perspective, the case where the interface between an organism and its environment becomes large enough that it acts as a buffer regulating their matter and energy exchanges. We illustrate the physiological and evolutionary role of buffers through the example of lungfish estivation. Then we ponder the relevance of buffers of this kind to the quest for a general definition of concepts like niche construction, the extended phenotype, and related ones, whose meaning is conveyed at present mostly through particular examples. Finally, we comment on the potential significance of buffers to organism—environment codetermination in the sense originally suggested by Lewontin.     

中国生态环境状况与生态文明建设

生态环境是人类生存和发展的主要物质来源,它承受着人类活动产生的废弃物和各种作用结果。良好的生态环境是人类发展最重要的前提,同时也是人类赖以生存、社会得以安定的基本条件。但目前全国生态环境问题日趋严峻,虽然当前环境状况在局部改善,但总体在恶化,治理速度远远赶不上破坏速度,生态环境破坏的程度在加剧,环境污染在加重,环境污染和破坏带来的危害也日趋明显,生态赤字逐渐扩大。生态文明是一种重视生态环境、重视环境保护的意识、价值观和文化,这意味着要解决当前日趋严峻的生态环境问题,进行生态文明建设是必要的。同时,我国经济的发展、科技的进步、法律法规的完善及社会环境保护意识的提高等使生态文明建设具有了可行性。因此,需要通过优化国土空间开发格局、调整能源利用结构、全面促进资源节约、加强生态文明制度建设、不断加强生态环境保护、转变经济增长方式等方面加强生态文明建设,为解决当前环境问题提供有效途径。     

土壤细菌类克隆群落及其结构的生态学特征

以16SrDNA分析方法为基础,获得来自不同土壤环境的细菌克隆群落（Cloning community),并分析了这些土壤细菌群落结构特征,在不同土壤环境中,细菌种类非常丰富,但其多样性将受到植被,土壤水分或土壤层次等因子的影响,表层土壤环境中细菌种类最丰富,多样性最高,且基因型中无明显的优势类群,不同土壤环境间细菌群落的相似性好低,表明群落结构以及空间隔离的复杂性。     

Phylogenetic diversity and ecological features in the Egyptian flora

Until fairly recently, regional-scale ecological and evolutionarypatterns have tended to be ignored as conservation efforts have been concernedwith species and their habitats. Here we compare frequencies in the Egyptianflora of particular rank sizes (order, family and genus) with patterns ofspecies abundance (classified as very rare, rare, common, or very common) and anarray of life-history attributes. The angiosperm flora of Egypt is representedby 2446 taxa (2088 species), including taxa in 10 subclasses, 51 orders, 120families, and 742 genera. A high degree of monotypism was observed: four ordersare monotypic (each existing as single species), and have very rare overallabundances; 30 families are monotypic (17 of which are very rare or rare); and 354genera are monotypic (over 70% of which are very rare or rare). Fourteenfamilies (in particular the Resedaceae and Zygophyllaceae) have at leastone-fifth of their global species represented in the Egyptian flora. Introducedspecies in general, and tree, aquatic herb and liana life forms all are especially well represented among monotypic genera. Native taxa are highlyrepresented among rare and very rare abundance classes, while introduced taxadid not differ significantly in their abundance patterns, compared to overallflora values. Few large genera (>20 spp.) occur in the flora, with mostspecies concentrated in genera containing 8–19 species per genus.Similarly, few families were highly speciose. Annual and herbaceous species weresignificantly over-represented, mainly among large, speciose genera andfamilies. However, perennials, trees, shrubs, aquatic herbs, lianas and parasiticspecies were found mainly in families and genera having very few taxa.Life-history attributes may have important implications to speciation rates.Taxonomically based results, involving abundances and life-history attributes,are discussed in the context of biodiversity and conservation.     

R factors in coliform-fecal coliform sewage flora of the prairies and Northwest Territories of Canada.

Coliform and fecal coliform populations found in the raw sewages and final sewage effluents of the prairie provinces and the Northwest Territories were examined for antibiotic resistance and the possession of R factors. It was determined that 8.91% of the total coliform and 10.80% of the fecal coliform populations carried R factors. The following numbers of combinations of R determinants were found: 39 in the Escherichia coli population, 6 in the Citrobacter population, 20 in the Enterobacter populations, 10 in the Klebsiella populations, and 11 in the Aeromonas populations. The maximum number of R determinants transferable simultaneously was seven; organisms with R factors containing determinants for chloramphenicol usually contained determinants for ampicillin. Of the coliform and fecal coliform populations, 2 to 4% were resistant to chloramphenicol in some provinces, and from 17 to 30% of the populations were resistant to three or more antibiotics. It was calculated that coliforms containing R factors in the raw sewage reached population levels of 1.5 X 10(7)/100 ml, and fecal coliforms containing R factors reached population levels of 8.6 X 10(5) ml. Final effluent discharges to the receiving environment contained R factor-containing coliform and fecal coliform populations of 3.1 X 10(4)/100 ml and 5.8 X 10(2)/100 ml, respectively. The incidence of bacteria containing R factors in sewage appears to be increasing with time, and their removal from sewage before discharge to the receiving environment is desirable. Consideration of data on bacteria with R factors should be made in future water quality deliberations and in discharge regulations.     

Horizontal transfer of a multi-drug resistance plasmid between coliform bacteria of human and bovine origin in a farm environment

Multi-drug-resistant coliform bacteria were isolated from feces of cattle exposed to antimicrobial agents and humans associated with the animals. Isolates from both cattle and humans harbored an R plasmid of 65 kb (pTMS1) that may have been transferred between them due to selective antibiotic pressure in the farm environment.     

Threatened woody flora as an ecological indicator of large herbivore introductions

Rewilding and translocations of large herbivores for conservation purposes have increased in recent times, with numerous introductions inside and outside their native range. This study aims to analyze the use of threatened plant taxa as a possible ecological indicator of large herbivore introductions. We examined the effects of a threatened large ungulate, the Barbary sheep (Ammotragus lervia), on both endangered and vulnerable woody taxa after its introduction in 1970. Contrary to our hypothesis, the herbivore impact on threatened woody species was higher than that found on widespread woody plants. The results reveal that 35.7% of the threatened species showed the highest possible level of herbivore damage in contrast to 6.5% for the widespread species. Threatened species were preferred over common plants, probably due to their greater palatability. Overall plant cover, including neighboring species, was also an important factor determining browsing damage and, thus, habitats with low ground cover should be particularly considered in conservation plans. Herbivore damage on common taxa should be taken with caution since they could mask unsustainable herbivore densities for threatened woody taxa or protected habitats. The use of threatened woody taxa through the studied ecological indicators (herbivore damage, plant preferences, habitat use and regeneration success) represented a useful tool to assess the sustainability of large herbivores introductions and to establish a priority conservation ranking for threatened plant species. These findings highlight the deleterious effects of overabundant ungulate populations regardless its origin (exotic or native) and the need of monitoring threatened woody taxa to better estimate the suitability and sustainability of large herbivore introductions.     

Characterization of the coliform and enteric bacilli in the environment of calves with colibacillosis

In the first part of the present study the coliform and enteric bacilli in the environment of calves with colibacillosis were examined. The occurrence, number, and pathogenic properties of Escherichia coli in barnyard soils were obtained from six cattle ranches. The O and K serogroups of E. coli isolates obtained from the feces of calves with colibacillosis born at these cattle ranches were determined, and their serotypes were compared with the E. coli O and K serotypes found in soils. The results showed a reservoir of potentially pathogenic E. coli in barnyard soils contaminated with bovine feces. For the second part of this study, 6 healthy calves and 51 calves with colibacillosis were studied. The numbers of total aerobic heterotrophic bacteria, total streptococci, fecal streptococci, total coliforms, and fecal coliforms in the feces of calves were determined. In addition, coliform and enteric bacilli from the feces of both healthy and diseased calves were identified, and their indole, methyl red, Voges-Proskauer, citrate (IMViC) types were described. In parallel, the IMViC types of coliform and enteric bacilli isolated from barnyard soils previously contaminated with bovine feces were compared with those isolated from uncontaminated soils. All fecal specimens were also examined for the presence of rotavirus. No significant effect on the numbers of the bacterial types was found. The results suggest that the predominant IMViC types found in the feces of calves with colibacillosis originate from the soil. From this study it is apparent that the occurrence, number, and survival of E. coli in barnyard soils is related to ranch husbandry and sanitary practices.     

武陵源风景名胜区旅游生态环境演变趋势与阈值分析

武陵源旅游业迅速发展的同时。景区生态环境质量逐年下降引起联合国教科文组织世界遗产委员会的关注：武陵源风景名胜区核心景区较突出的生态环境问题,主要表现在大气环境质量逐年降低;金鞭溪水质明显恶化;生物多样性受到威胁;景区城镇化、工商业比速度加快等。通过实地监测并全面分析武陵源风景名胜区环境演变趋势。发现住宿设施对环境的影响。比其他游乐设施更为明显,是武陵源风景名胜区旅游生态环境的关键影响因子。景区水质监测值的变化最大,表明水体是景区生态环境中最为脆弱的环境因子：随着游客的逐年增多。旅游生态环境呈现出加速恶化的趋势。通过建立基于环境脆弱因子的阈值模型,计算得出在不超出武陵源风景名胜区景区最为脆弱的环境因子——景区水质标准：总磷≤0．02(mg/L)前提下。景区上游接待区旅游生态阈值是春季宾馆可使用面积容限为29650m^2。夏季为76425m^2。秋季为13625m^2。冬季为8325m^2。不同类型的风景区。生态环境脆弱因子不同。宾馆建筑面积容限位也不同。沿着本文思路。可计算出其他类型风景区阈值。     

BASECO: a floristic and ecological database of Mediterranean French flora

The French Mediterranean zone is one of the richest of the country, with 3200 species and many endemics. Because of its interest as a synthetic tool to store and manage data, an ecological Mediterranean flora database was created. Built around five tables, BASECO allows several queries about the botanical and ecological characteristics of about 1800 plants. The database was implemented in Access, which is a relational database management system. Each species is identified by a code and is characterised by several qualitative traits relating to morphology, reproduction, life forms and biogeographical distribution, including several modalities. Each trait is informed from one or two pre-defined reference botanical handbooks as much as possible. There are many different possible uses of this database, even at a huge scale, allowing to reveal patterns hard to detect with the taxonomic approach alone.     

Characterization of the coliform and enteric bacilli in the environment of calves with colibacillosis.

In the first part of the present study the coliform and enteric bacilli in the environment of calves with colibacillosis were examined. The occurrence, number, and pathogenic properties of Escherichia coli in barnyard soils were obtained from six cattle ranches. The O and K serogroups of E. coli isolates obtained from the feces of calves with colibacillosis born at these cattle ranches were determined, and their serotypes were compared with the E. coli O and K serotypes found in soils. The results showed a reservoir of potentially pathogenic E. coli in barnyard soils contaminated with bovine feces. For the second part of this study, 6 healthy calves and 51 calves with colibacillosis were studied. The numbers of total aerobic heterotrophic bacteria, total streptococci, fecal streptococci, total coliforms, and fecal coliforms in the feces of calves were determined. In addition, coliform and enteric bacilli from the feces of both healthy and diseased calves were identified, and their indole, methyl red, Voges-Proskauer, citrate (IMViC) types were described. In parallel, the IMViC types of coliform and enteric bacilli isolated from barnyard soils previously contaminated with bovine feces were compared with those isolated from uncontaminated soils. All fecal specimens were also examined for the presence of rotavirus. No significant effect on the numbers of the bacterial types was found. The results suggest that the predominant IMViC types found in the feces of calves with colibacillosis originate from the soil. From this study it is apparent that the occurrence, number, and survival of E. coli in barnyard soils is related to ranch husbandry and sanitary practices.     

The shape of an ecological trade-off varies with environment

Central to most theories that explain the diversity of life is the concept that organisms face trade-offs. Theoretical work has shown that the precise shape of a trade-off relationship affects evolutionary predictions. One common trade-off is that between competitive ability and resistance to predators, parasitoids, pathogens or herbivores. We used a microbial experimental system to elucidate the shape of the relationship between parasitoid resistance and competitive ability. For each of 86 bacteriophage-resistant isolates of the bacterium Escherichia coli B, we measured the degree of resistance to bacteriophage T2 (a viral parasitoid) and relative competitive ability in both the resource environment in which strains were isolated and in two alternate environments. We observed that environmental change can alter trade-off shape, and that different physiological mechanisms can lead to different trade-off shapes and different sensitivities to environmental change. These results highlight the important interaction between environment and trade-off shape in affecting ecological and evolutionary dynamics.     

Kleptoparasitism in gulls Laridae at an urban and a coastal foraging environment: an assessment of ecological predictors

Capsule: Kleptoparasitism in gulls occurred at a greater rate at an urban compared with a coastal site. Population density and prey size predicted the rate of kleptoparasitism at the urban site.

Aims: To investigate and assess the ecological variables associated with kleptoparasitism among gulls at urban and rural sites.

Methods: Field observations were conducted at Brancaster (coastal rural) and Billingsgate Market (urban) to examine differences in the rate of kleptoparasitism in mixed-species flocks of gulls. Four key variables (prey size, population density, season and species) were assessed as predictors of kleptoparasitism.

Results: Generalized linear models revealed significant effects on kleptoparasitism rate of site, population density and prey size, and two-way interactions between these main terms. Population density and prey size differed significantly between sites, but population density appeared to predict the rate of kleptoparasitism.

Conclusion: Kleptoparasitism may well aid invasion and increase the range of environments a gull can tolerate by helping them meet their energy needs in novel environments where normal foraging behaviours are difficult to implement.     

湿地生态环境影响评价初步探讨

探讨了湿地生态环境影响评价的理论框架 ,指出由于湿地生态环境的特殊性 ,应将非污染型生态环境影响评价放到重要位置。应重视工程项目对湿地水文条件、植物区系、动物种群改变以及移民和诱导开发的影响分析。从湿地分类开始 ,以湿地功能为核心建立评价指标体系 ,把湿地潜在的生态环境效益和工程项目可能产生影响有机结合在一起 ,评价建设项目的急性和慢性影响 ,提出减缓影响的措施和替代方案。着眼于维持现存的生态过程和自然系统 ,保护湿地的生态效益和功能 ,为湿地可持续利用服务     

Hospital outbreak of trimethoprim resistance in pathogenic coliform bacteria.

In an investigation of outbreak of infection caused by coliform bacilli with plasmid-mediated trimethoprim (TMP) resistance many patients were found to be asymptomatic carriers of TMP-resistant coliform bacilli. Analysis of factors predisposing to rectal carriage of these organisms showed that the most important was previous treatment with co-trimoxazole, a sulphonamide, or ampicillin. The outbreak was controlled by a policy restricting the antibiotics given. Geriatric units are an important source of hospital infection. When an outbreak occurs the logical sequence of steps to be taken is to monitor cases, identify the outbreaks, analyse the causative factors, plan corrective action jointly with laboratory staff, and monitor the outcome.