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排序方式: 共有117条查询结果,搜索用时 0 毫秒
1.
Ziegler T Matikainen S Rönkkö E Osterlund P Sillanpää M Sirén J Fagerlund R Immonen M Melén K Julkunen I 《Journal of virology》2005,79(21):13800-13805
Activation of host innate immune responses was studied in severe acute respiratory syndrome coronavirus (SCV)-infected human A549 lung epithelial cells, macrophages, and dendritic cells (DCs). In all cell types, SCV-specific subgenomic mRNAs were seen, whereas no expression of SCV proteins was found. No induction of cytokine genes (alpha interferon [IFN-alpha], IFN-beta, interleukin-28A/B [IL-28A/B], IL-29, tumor necrosis factor alpha, CCL5, or CXCL10) or IFN-alpha/beta-induced MxA gene was seen in SCV-infected A549 cells, macrophages, or DCs. SCV also failed to induce DC maturation (CD86 expression) or enhance major histocompatibility complex class II expression. Our data strongly suggest that SCV fails to activate host cell cytokine gene expression in human macrophages and DCs. 相似文献
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Frank Wätzold Melanie Mewes Rob van Apeldoorn Riku Varjopuro Tadeusz Jan Chmielewski Frank Veeneklaas Marja-Leena Kosola 《Biodiversity and Conservation》2010,19(7):2053-2069
Natura 2000 sites are expected to assure the long-term survival of Europe’s most valuable and threatened species and habitats. It follows that successful management of the sites is of great importance. Next to goal attainment, cost-effectiveness is increasingly recognised as a key requirement for gaining social and political acceptance for costly conservation measures. We identify and qualitatively examine issues of cost-effectiveness related to the design and implementation of management measures in Natura 2000 sites in Finland, Germany, the Netherlands and Poland. Given the wide variety of management design and implementation options within the four countries, our study is purely of an exploratory nature. We derive recommendations for improving the cost-effectiveness of management in Natura 2000 sites and for future research. Examples of policy recommendations include guaranteeing the availability of funds for longer periods, and ensuring the appropriate allocation of funds between the different tasks of designing and implementing management plans. Further research should examine the cost-effectiveness of controversial suggestions such as, for example, more tailored payment schemes for conservation measures that result in higher ecological outputs but are costly to administer. Moreover, more research is needed to better understand how rules for administrations, as well as rules and governance structures for tasks within administrations, should be designed. 相似文献
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Effect of polysaccharide structure on mechanical and thermal properties of galactomannan-based films
Films were prepared from guar gum and locust bean gum galactomannans. In addition, enzymatic modification was applied to guar gum to obtain structurally different galactomannans. Cohesive and flexible films were formed from galactomannans plasticized with 20-60% (w/w of polymer) glycerol or sorbitol. Galactomannans with lower galactose content (locust bean gum, modified guar gum) produced films with higher elongation at break and tensile strength. The mechanical properties of films were improved statistically significantly by decreasing the degree of polymerization of guar gum with mannanase treatments (4 h) of 2 and 10 nkat/g, whereas 50 nkat/g produced films with low elongation at break and tensile strength. Galactomannans with approximately 6 galactose units per 10 mannose backbone units resulted in films with 2 peaks in loss modulus spectra, whereas films from galactomannans with approximately 2 galactose groups per 10 mannose units behaved as a single phase in dynamic mechanical analysis. 相似文献
6.
Janne Soininen Riku Paavola Janina Kwandrans Timo Muotka 《Biodiversity and Conservation》2009,18(1):79-89
As wholesale biodiversity assessment is often impractical, the use of surrogates that reflect the assemblage structure and
diversity of other taxa has attracted increased attention. We sampled 47 boreal streams for diatoms and macroalgae and examined
their assemblage patterns along major environmental gradients. Our main intention was to examine whether diatoms might be
useful surrogates for macroalgae in boreal streams. We also assessed whether taxon richness and community composition provided
similar insights into the patterns of cross-taxon concordance. According to canonical correspondence analysis, diatom distribution
was most strongly related to water pH, conductivity, latitude and longitude, and macroalgal distribution to water pH and iron
content, latitude and bed instability. In Mantel’s test, diatoms and macroalgae showed significant cross-taxon concordance.
However, there was no significant correlation between taxon richness of the two algal groups, likely reflecting their differing
responses to environmental variables. We found evidence that although diatoms and macroalgae are partly controlled by different
environmental factors, they are segregated rather similarly along latitude and a few environmental gradients such as water
pH and iron content. We conclude that, at least at broad geographical extents and in small streams, diatoms reflect the structure
of the macroalgal community and are therefore useful surrogates for cost-effective biomonitoring of algal communities in streams. 相似文献
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J Pospísil F Kase J Vahala I Mouchová 《Comparative biochemistry and physiology. A, Comparative physiology》1984,78(4):815-821
Comparison of mean erythrocyte counts, mean haematocrit values, mean haemoglobin content and mean corpuscular volume of the red cell is presented for 21 species of antelopes (four species being excluded because of the small number of animals investigated). A direct relationship of haematocrit values and haemoglobin content and an inverse relationship of red cell counts and mean corpuscular volume of the erythrocytes were noted. The significance of an increased total surface area for oxygen exchange is discussed and values obtained in the red blood picture are compared with those of domesticated animals (cattle, goat and sheep) taken from the literature. Mean leukocyte counts were found to be in the human range with the exception of two species, but significantly lower than in domesticated artiodactylids. Problems in assessing the general health, the age, the effect of diet and of environment in captivity are discussed. Problems of methodology, especially of blood sampling, are given comparing results in manually restrained and in sedated animals. 相似文献
9.
Zhe Zhao Tapio Kesti Hasan Uurlu Andreas S. Baur Riku Fagerlund Kalle Saksela 《Traffic (Copenhagen, Denmark)》2019,20(3):202-212
When studying how HIV‐1 Nef can promote packaging of the proinflammatory transmembrane protease TACE (tumor necrosis factor‐α converting enzyme) into extracellular vesicles (EVs) we have revealed a novel tyrosine kinase‐regulated unconventional protein secretion (UPS) pathway for TACE. When TACE was expressed without its trafficking cofactor iRhom allosteric Hck activation by Nef triggered translocation of TACE into EVs. This process was insensitive to blocking of classical secretion by inhibiting endoplasmic reticulum (ER) to Golgi transport, and involved a distinct form of TACE devoid of normal glycosylation and incompletely processed for prodomain removal. Like most other examples of UPS this process was Golgi reassembly stacking protein (GRASP)‐dependent but was not associated with ER stress. These data indicate that Hck‐activated UPS provides an alternative pathway for TACE secretion that can bypass iRhom‐dependent ER to Golgi transfer, and suggest that tyrosine phosphorylation might have a more general role in regulating UPS. 相似文献
10.
Are biological classifications of headwater streams concordant across multiple taxonomic groups? 总被引:10,自引:1,他引:10
Riku Paavola Timo Muotka Risto Virtanen Jani Heino Petri Kreivi 《Freshwater Biology》2003,48(10):1912-1923
1. Studies assessing human impacts on freshwater ecosystems are typically based on a single taxonomic group, often macroinvertebrates or fish. Unfortunately, the degree to which such macroinvertebrate or fish‐based surveys can be generalised across other taxonomic groups remains largely unknown. A prerequisite for useful generalisations is that different taxonomic groups exhibit concordant patterns of community structure across sites. 2. We examined the concordance among fish, benthic macroinvertebrates and bryophytes in 32 streams in a boreal catchment in Finland. Our goal was to test how consistently different taxonomic groups classify stream sites; for example, can site groupings based on macroinvertebrates be used as a surrogate for bryophyte or fish assemblage classification? 3. Our results show that community classifications in headwater streams are not concordant across taxonomic groups, at least not at the within‐river system scale. The lack of concordance reflected the fact that all three groups responded to different environmental factors. Macroinvertebrate community structure was mainly correlated with stream size and pH, whereas bryophytes were related to water colour, nutrient content and in‐stream habitat variability. Fish community structure was best described by stream depth, substrate size and water oxygen concentration. 4. Our results suggest that great care should be taken when typologies based on benthic macroinvertebrates, or any other taxonomic group, are extrapolated to other groups in creating typologies of lotic environments. 相似文献