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61.
62.
Auto, a surface associated autolysin of Listeria monocytogenes required for entry into eukaryotic cells and virulence 总被引:3,自引:0,他引:3
Listeria monocytogenes is an opportunistic food-borne human and animal pathogen. Several surface proteins expressed by this intracellular pathogen are critical for the infectious process. By in silico analysis we compared the surface protein repertories of L. monocytogenes and of the non-pathogenic species Listeria innocua and identified a gene encoding a surface protein of L. monocytogenes absent in L. innocua. This gene that we named aut encodes a protein (Auto) of 572 amino acids containing a signal sequence, a N-terminal autolysin domain and a C-terminal cell wall-anchoring domain made up of four GW modules. We show here that the aut gene is expressed independently of the virulence gene regulator PrfA and encodes a surface protein with an autolytic activity. We provide evidence that Auto is required for entry of L. monocytogenes into cultured non-phagocytic eukaryotic cells. The low invasiveness of an aut deletion mutant correlates with its reduced virulence following intravenous inoculation of mice and oral infection of guinea pigs. During infection, the autolytic activity of Auto may also be critical. Auto appears thus as a novel type of L. monocytogenes virulence factor. 相似文献
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A unified framework to model the potential and realized distributions of invasive species within the invaded range 下载免费PDF全文
Tarek Hattab Carol X. Garzón‐López Michael Ewald Sandra Skowronek Raf Aerts Hélène Horen Boris Brasseur Emilie Gallet‐Moron Fabien Spicher Guillaume Decocq Hannes Feilhauer Olivier Honnay Pieter Kempeneers Sebastian Schmidtlein Ben Somers Ruben Van De Kerchove Duccio Rocchini Jonathan Lenoir 《Diversity & distributions》2017,23(7):806-819
65.
Mercedes Bustamante Carmenza Robledo‐Abad Richard Harper Cheikh Mbow Nijavalli H. Ravindranat Frank Sperling Helmut Haberl Alexandre de Siqueira Pinto Pete Smith 《Global Change Biology》2014,20(10):3270-3290
The agriculture, forestry and other land use (AFOLU) sector is responsible for approximately 25% of anthropogenic GHG emissions mainly from deforestation and agricultural emissions from livestock, soil and nutrient management. Mitigation from the sector is thus extremely important in meeting emission reduction targets. The sector offers a variety of cost‐competitive mitigation options with most analyses indicating a decline in emissions largely due to decreasing deforestation rates. Sustainability criteria are needed to guide development and implementation of AFOLU mitigation measures with particular focus on multifunctional systems that allow the delivery of multiple services from land. It is striking that almost all of the positive and negative impacts, opportunities and barriers are context specific, precluding generic statements about which AFOLU mitigation measures have the greatest promise at a global scale. This finding underlines the importance of considering each mitigation strategy on a case‐by‐case basis, systemic effects when implementing mitigation options on the national scale, and suggests that policies need to be flexible enough to allow such assessments. National and international agricultural and forest (climate) policies have the potential to alter the opportunity costs of specific land uses in ways that increase opportunities or barriers for attaining climate change mitigation goals. Policies governing practices in agriculture and in forest conservation and management need to account for both effective mitigation and adaptation and can help to orient practices in agriculture and in forestry towards global sharing of innovative technologies for the efficient use of land resources. Different policy instruments, especially economic incentives and regulatory approaches, are currently being applied however, for its successful implementation it is critical to understand how land‐use decisions are made and how new social, political and economic forces in the future will influence this process. 相似文献
66.
Olivier Beauchard Quiterie Duron Thierry Oberdorff Sébastien Brosse 《Global Ecology and Biogeography》2011,20(3):407-414
Aim We tested whether coarse‐grained occurrence data can be used to detect climatic niche shifts between native and non‐native ranges for a set of widely introduced freshwater fishes. Location World‐wide. Methods We used a global database of freshwater fish occurrences at the river basin scale to identify native and non‐native ranges for 18 of the most widely introduced fish species. We also examined climatic conditions within each river basin using fine‐grained climate data. We combined this information to test whether climatic niche shifts have occurred between native and non‐native ranges. We defined climatic niche shifts as instances where the ranges of a climatic variable within native and non‐native basins exhibit zero overlap. Results We detected at least one climatic niche shift for each of the 18 studied species. However, we did not detect common patterns in the thermal preference or biogeographic origin of the non‐native fish, hence suggesting a species‐specific response. Main conclusions Coarse‐grained occurrence data can be used to detect climatic niche shifts. They also enable the identification of the species experiencing niche shifts, although the mechanisms responsible for these shifts (e.g. local adaptation, dispersal limitation or physiological constraints) have yet to be determined. Furthermore, the coarse‐grained approach, which highlights regions where climatic niche shifts have occurred, can be used to select specific river basins for more detailed, fine‐grained studies. 相似文献
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Mouaadh Abdelkarim Sandrine Caron Christian Duhem Janne Prawitt Julie Dumont Anthony Lucas Emmanuel Bouchaert Olivier Briand John Brozek Folkert Kuipers Catherine Fievet Bertrand Cariou Bart Staels 《The Journal of biological chemistry》2010,285(47):36759-36767
The bile acid receptor farnesoid X receptor (FXR) is expressed in adipose tissue, but its function remains poorly defined. Peroxisome proliferator-activated receptor-γ (PPARγ) is a master regulator of adipocyte differentiation and function. The aim of this study was to analyze the role of FXR in adipocyte function and to assess whether it modulates PPARγ action. Therefore, we tested the responsiveness of FXR-deficient mice (FXR−/−) and cells to the PPARγ activator rosiglitazone. Our results show that genetically obese FXR−/−/ob/ob mice displayed a resistance to rosiglitazone treatment. In vitro, rosiglitazone treatment did not induce normal adipocyte differentiation and lipid droplet formation in FXR−/− mouse embryonic fibroblasts (MEFs) and preadipocytes. Moreover, FXR−/− MEFs displayed both an increased lipolysis and a decreased de novo lipogenesis, resulting in reduced intracellular triglyceride content, even upon PPARγ activation. Retroviral-mediated FXR re-expression in FXR−/− MEFs restored the induction of adipogenic marker genes during rosiglitazone-forced adipocyte differentiation. The expression of Wnt/β-catenin pathway and target genes was increased in FXR−/− adipose tissue and MEFs. Moreover, the expression of several endogenous inhibitors of this pathway was decreased early during the adipocyte differentiation of FXR−/− MEFs. These findings demonstrate that FXR regulates adipocyte differentiation and function by regulating two counteracting pathways of adipocyte differentiation, the PPARγ and Wnt/β-catenin pathways. 相似文献
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Marine actinomycetes as a source of novel secondary metabolites 总被引:6,自引:4,他引:6
Fiedler HP Bruntner C Bull AT Ward AC Goodfellow M Potterat O Puder C Mihm G 《Antonie van Leeuwenhoek》2005,87(1):37-42
A set of 600 actinomycetes strains which were isolated from marine sediments from various sites in the Pacific and Atlantic Oceans were screened for the production of bioactive secondary metabolites. Marine streptomycete strains were found to be producers of well known chemically diverse antibiotics isolated from terrestrial streptomycetes, as in the case of marine Micromonospora strains. New marine members of the rare genus Verrucosispora seem to be a promising source for novel bioactive secondary metabolites as shown in the case of the abyssomicin producing strain AB-18-032. 相似文献