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991.
Microorganisms are famous for adapting quickly to new environments. However, most evidence for rapid microbial adaptation comes from laboratory experiments or domesticated environments, and it is unclear how rates of adaptation scale from human‐influenced environments to the great diversity of wild microorganisms. We examined potential monthly‐scale selective pressures in the model forest yeast Saccharomyces paradoxus. Contrary to expectations of seasonal adaptation, the S. paradoxus population was stable over four seasons in the face of abiotic and biotic environmental changes. While the S. paradoxus population was diverse, including 41 unique genotypes among 192 sampled isolates, there was no correlation between S. paradoxus genotypes and seasonal environments. Consistent with observations from other S. paradoxus populations, the forest population was highly clonal and inbred. This lack of recombination, paired with population stability, implies that selection is not acting on the forest S. paradoxus population on a seasonal timescale. Saccharomyces paradoxus may instead have evolved generalism or phenotypic plasticity with regard to seasonal environmental changes long ago. Similarly, while the forest population included diversity among phenotypes related to intraspecific interference competition, there was no evidence for active coevolution among these phenotypes. At least ten percent of the forest S. paradoxus individuals produced “killer toxins,” which kill sensitive Saccharomyces cells, but the presence of a toxin‐producing isolate did not predict resistance to the toxin among nearby isolates. How forest yeasts acclimate to changing environments remains an open question, and future studies should investigate the physiological responses that allow microbial cells to cope with environmental fluctuations in their native habitats.  相似文献   
992.
牙形刺作为牙形动物的咽部进食器官,具有其独特的生物学特征。基于山东青州尧王山寒武系-奥陶系剖面产出的较丰富的牙形刺化石资料,本文讨论了牙形刺在牙形动物行使滤食等进食功能时产生的生理性磨损,与前人对石炭纪牙形刺的磨损类型的三种:破裂(指牙形刺的突出部分受外力而折断、脱离牙形刺主体的现象)、剥落(外层的生长层被剥落,而露出内层的生长层)、磨光(指牙形刺表面的纹饰在磨蚀作用下变浅或变得光滑)进行了对比,并提出一种新的磨损方式:磨花(与磨光类似,然而原有纹饰变浅或消失之后,继续磨蚀而使刺体表面变得不光滑的现象),以及磨损后修复的现象。根据磨损类型分析,将牙形动物的取食方式分为"沙粒翻找型"与"浮游捕食型"两种。为推测牙形动物的取食方式提供佐证。  相似文献   
993.
盐生荒漠净生态系统碳交换的涡度相关法和箱式法对比   总被引:1,自引:0,他引:1  
马杰  吴玉  郑新军  唐立松  王玉刚 《生态学杂志》2013,32(10):2627-2634
将叶面积指数的季节动态,与箱式法同步观测得到的同化枝净光合(呼吸)速率和土壤呼吸速率相结合,对群落碳交换进行估算,并以此验证盐生荒漠涡度相关数据的可靠性。结果表明:盐生荒漠生态系统年叶片生物量为51.30±5.56 g·m-2,其中90.45%以上来源于多枝柽柳的贡献;而整个生长季,群落叶面积指数(LAI)呈单峰形式变化,从5月30日—9月30日,LAI介于0.180.30,并在第197天达到最大值。涡度相关法和箱式法对群落碳交换的测定结果表明,群落碳交换存在显著的季节变化,并于7月中旬达到碳同化峰值,与LAI有显著的相关性(P<0.001)。对比发现,两种测量方法对群落碳交换日过程的测定结果有很好的一致性,但对夜间生态系统呼吸的测定,涡度相关法较箱式法存在略微的低估,引起这种低估的原因可能是夜间湍流较弱。  相似文献   
994.
Earth observation environmental features measured through remote sensing and models of vector mosquitoes species Aedes aegypti and Ae. albopictus provide an advancement with regards to dengue risk in urban environments of subtropical areas of Argentina. The authors aim to estimate the effect of landscape coverage and spectral indices (Normalized Difference Vegetation Index [NDVI], Normalized Difference Water Index [NDWI] and Normalized Difference Built-up Index [NDBI]) on the larvae abundance of Ae. aegypti and Ae. albopictus in Eldorado, Misiones, Argentina using remote satellite sensors. Larvae of these species were collected monthly (June 2016 to April 2018), in four environments: tire repair shops, cemeteries, dwellings and an urban natural park. The proportion of landscape coverage (water, urban areas, bare soil, low vegetation and high vegetation) was determined from the supervised classification of Sentinel-2 images and spectral indices, calculated. The authors developed spatial models of both vector species by generalized linear mixed models. The model's results showed that Ae. aegypti larvae abundance was better modelled by NDVI minimum values, NDBI maximum values and the interaction between them. For Ae. albopictus proportion of bare soil, low vegetation and the interaction between both variables explained better the abundance.  相似文献   
995.
Industrial ecology (IE) methodologies, such as input/output or material flow analysis and life cycle assessment (LCA), are often used for the environmental evaluation of circular economy strategies. Up to now, an approach that utilizes these methods in a systematic, integrated framework for a holistic assessment of a geographic region's sustainable circular economy potential has been lacking. The approach developed in this study (IE4CE approach) combines IE methodologies to determine the environmental impact mitigation potential of circular economy strategies for a defined geographic region. The approach foresees five steps. First, input/output analysis helps identify sectors with high environmental impacts. Second, a refined analysis is conducted using material flow and LCA. In step 3, circular strategies are used for scenario design and evaluated in step 4. In step 5, the assessment results are compiled and compared across sectors. The approach was applied to a case study of Switzerland, analyzing 8 sectors and more than 30 scenarios in depth. Carbon capture and storage (CCS) from waste incineration, biogas and cement production, food waste prevention in households, hospitality and production, and the increased recycling of plastics had the highest mitigation potential. Most of the scenarios do not influence each other. One exception is the CCS scenarios: waste avoidance scenarios decrease the reduction potential of CCS. A combination of scenarios from different sectors, including their impact on the CCS scenario potential, led to an environmental impact mitigation potential of 11.9 Mt CO2-eq for 2050, which equals 14% of Switzerland's current consumption-based impacts.  相似文献   
996.
Reducing food waste is essential if we want to create a more sustainable food system, which is why halving per capita food waste by 2030 has been included in the UN Sustainable Development Goals. The main aim of this paper is to demonstrate that by using digital tools to monitor food provisioning and management within canteens, it is possible to achieve a more sustainable food service management within industrial companies and to reduce the overall quantity and environmental impacts of food preparation and consumption thus achieving economic benefits. Longitudinal 2018 and 2019 data collected from the canteen of a major Italian food production company were analyzed. The results showed that the amount of food lost and wasted has decreased over time, reaping important environmental benefits and illustrating specific differences between the food lost in meal preparation and the food left on employees’ plates. It is therefore important to implement education initiatives and to use digital tools to share food-related data collected within companies among both employees and kitchen and catering staff in order to raise awareness of their behavioral strengths and weaknesses. From this perspective, new interventions at both kitchen and customer/worker levels are introduced and discussed.  相似文献   
997.
Policymaking mediates the relationships between manufacturers and consumers, thus defining the boundaries for the philosophies of production set forth by major companies. Research states that policymaking falls short in addressing the waste issues, natural resources consumption, greenhouse gas emissions, and other negative impacts posed by premature obsolescence; only recently have the “right-to-repair” guidelines demanded by environmental organizations and communities of citizens been included in policymaking. The introduction of the Index of Repairability in France as information at the point of sale aims to inform consumers and support their decision-making in purchasing more repairable products. In this paper, we consider the two Indexes of Repairability publicly available to consumers—in the French legislation and iFixit—and assess their application to smartphones from three manufacturers. The study establishes links between the scores and the industrial design features that promote or hinder repairability, service factors and information for self-repair, authorized repair, and independent repair. Data collection considers the available information for consumers and citizens by using netnography and secondary data from manufacturers, policymakers, and communities of users. Our findings suggest that higher scores that indicate easier repairability are not limited to product architectures that follow design for disassembly guidelines. Smartphones that are difficult to repair can still score high, and thus be perceived as easier to repair, if manufacturers provide high quality and affordable service. This paper discusses the results of the ongoing development of repairability scores for smartphones, thus suggesting paths for future research to improve methods and policies to support a longer lifetime of products.  相似文献   
998.
An investigation of population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) was carried out in the Chebera Churchura National Park, Ethiopia during the wet and dry seasons of 2005–2006. Sample counts of African buffaloes were carried out in an area of 1,215 km2. The estimated population of buffalo was 2,617 individuals. Males comprised 35.0%, while females 52.8% of the population. The remaining 12% of the population was young of both sexes and of all ages of unknown sex. It was difficult to categorize the young into male and female in the field, as their primary sexual characteristics were not easily visible. Male to female sex ratio was 1.00 : 1.51. Age structure was dominated by adults, which constituted 72.06% of the total population. Subadults comprised 22.02%, and young accounted for 5.9% of the population. Larger herds of up to 27 individuals were observed during the wet season and smaller herds of eight individuals during the dry season. The mean herd size during wet and dry seasons was 24.81 and 7.77, respectively. The African buffaloes were distributed in four habitat types such as grasslands, woodlands, montane forests and riverine habitat in the study area. They were observed more in the riverine vegetation types during the dry season. Relative abundance of food resources, green vegetation cover and water availability in the area were the major factors governing their distribution in the present study area. They spent a greater proportion of the time in feeding and resting/ruminating activities. On the average, 49.7% of the daytime was spent in feeding, and 38.75% of the day on resting (lying down and standing). Morning and the late afternoon activity peaks were more pronounced during the dry season than the wet season.  相似文献   
999.
A road map for molecular ecology   总被引:1,自引:0,他引:1  
The discipline of molecular ecology has undergone enormous changes since the journal bearing its name was launched approximately two decades ago. The field has seen great strides in analytical methods development, made groundbreaking discoveries and experienced a revolution in genotyping technology. Here, we provide brief perspectives on the main subdisciplines of molecular ecology, describe key questions and goals, discuss common challenges, predict future research directions and suggest research priorities for the next 20 years.  相似文献   
1000.
The widespread use of monoclonal antibodies (mAbs) as a platform for therapeutic drug development in the pharmaceutical industry has led to an increased interest in robust experimental approaches for assessment of mAb structure, stability and dynamics. The ability to enrich proteins with stable isotopes is a prerequisite for the in-depth application of many structural and biophysical methods, including nuclear magnetic resonance (NMR), small angle neutron scattering, neutron reflectometry, and quantitative mass spectrometry. While mAbs can typically be produced with very high yields using mammalian cell expression, stable isotope labeling using cell culture is expensive and often impractical. The most common and cost-efficient approach to label proteins is to express proteins in Escherichia coli grown in minimal media; however, such methods for mAbs have not been reported to date. Here we present, for the first time, the expression and purification of a stable isotope labeled mAb from a genetically engineered E. coli strain capable of forming disulfide bonds in its cytoplasm. It is shown using two-dimensional NMR spectral fingerprinting that the unlabeled mAb and the mAb singly or triply labeled with 13C, 15N, 2H are well folded, with only minor structural differences relative to the mammalian cell-produced mAb that are attributed to the lack of glycosylation in the Fc domain. This advancement of an E. coli-based mAb expression platform will facilitate the production of mAbs for in-depth structural characterization, including the high resolution investigation of mechanisms of action.  相似文献   
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