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71.
Plant and Soil - As different plant species support different soil communities, assessment of climate change impacts on soil communities must consider how these impacts depend on the vegetation. We... 相似文献
72.
Jensen LF Hansen MM Pertoldi C Holdensgaard G Mensberg KL Loeschcke V 《Proceedings. Biological sciences / The Royal Society》2008,275(1653):2859-2868
Knowledge of local adaptation and adaptive potential of natural populations is becoming increasingly relevant due to anthropogenic changes in the environment, such as climate change. The concern is that populations will be negatively affected by increasing temperatures without the capacity to adapt. Temperature-related adaptability in traits related to phenology and early life history are expected to be particularly important in salmonid fishes. We focused on the latter and investigated whether four populations of brown trout (Salmo trutta) are locally adapted in early life-history traits. These populations spawn in rivers that experience different temperature conditions during the time of incubation of eggs and embryos. They were reared in a common-garden experiment at three different temperatures. Quantitative genetic differentiation (QST) exceeded neutral molecular differentiation (FST) for two traits, indicating local adaptation. A temperature effect was observed for three traits. However, this effect varied among populations due to locally adapted reaction norms, corresponding to the temperature regimes experienced by the populations in their native environments. Additive genetic variance and heritable variation in phenotypic plasticity suggest that although increasing temperatures are likely to affect some populations negatively, they may have the potential to adapt to changing temperature regimes. 相似文献
73.
Through lysis of bacterioplankton cells, viruses mediate an important, but poorly understood, pathway of carbon and nutrients from the particulate to the dissolved form. Via this activity, nutrient-rich cell lysates may become available to noninfected cells and support significant growth. However, the nutritional value of lysates for noninfected bacteria presumably depends on the prevailing nutrient limitation. In the present study, we examined dynamics of dissolved DNA (D-DNA) and viruses along a transect in the phosphorus (P)-limited Ore Estuary, northern Baltic Sea. We found that viruses were an important mortality factor for bacterioplankton and that their activity mediated a significant recycling of carbon and especially of P. Uptake of dissolved DNA accounted for up to 70% of the bacterioplankton P demand, and about a quarter of the D-DNA pool was supplied through viral lysis of bacterial cells. Generally, the importance of viral lysates and uptake of D-DNA was highest at the estuarine and offshore stations and was positively correlated with P limitation measured as alkaline phosphatase activity. Our results highlight the importance of viral activity for the internal recycling of principal nutrients and pinpoints D-DNA as a particularly relevant compound in microbial P dynamics. 相似文献
74.
Ilka Hoof Bjoern Peters John Sidney Lasse Eggers Pedersen Alessandro Sette Ole Lund Søren Buus Morten Nielsen 《Immunogenetics》2009,61(1):1-13
Binding of peptides to major histocompatibility complex (MHC) molecules is the single most selective step in the recognition
of pathogens by the cellular immune system. The human MHC genomic region (called HLA) is extremely polymorphic comprising
several thousand alleles, each encoding a distinct MHC molecule. The potentially unique specificity of the majority of HLA
alleles that have been identified to date remains uncharacterized. Likewise, only a limited number of chimpanzee and rhesus
macaque MHC class I molecules have been characterized experimentally. Here, we present NetMHCpan-2.0, a method that generates quantitative predictions of the affinity of any peptide–MHC class I interaction. NetMHCpan-2.0 has been trained on the hitherto largest set of quantitative MHC binding data available, covering HLA-A and HLA-B, as well
as chimpanzee, rhesus macaque, gorilla, and mouse MHC class I molecules. We show that the NetMHCpan-2.0 method can accurately predict binding to uncharacterized HLA molecules, including HLA-C and HLA-G. Moreover, NetMHCpan-2.0 is demonstrated to accurately predict peptide binding to chimpanzee and macaque MHC class I molecules. The power of NetMHCpan-2.0 to guide immunologists in interpreting cellular immune responses in large out-bred populations is demonstrated. Further,
we used NetMHCpan-2.0 to predict potential binding peptides for the pig MHC class I molecule SLA-1*0401. Ninety-three percent of the predicted
peptides were demonstrated to bind stronger than 500 nM. The high performance of NetMHCpan-2.0 for non-human primates documents the method’s ability to provide broad allelic coverage also beyond human MHC molecules.
The method is available at .
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
75.
Lasse Ruokolainen Esa Ranta Veijo Kaitala Mike S. Fowler 《Journal of theoretical biology》2009,261(3):379-387
The outcome of species interactions in a variable environment is expected to depend on how similarly different species react to variation in environmental conditions. We study community stability (evenness and species diversity) in competitive communities that are either closed or subjected to random migration, under different regimes of environmental forcing. Community members respond to environmental variation: (i) independently (IR), (ii) in a positively correlated way (CR), or (iii) hierarchically, according to niche differences (HR). Increasing the amplitude of environmental variation and environmental reddening both reduce species evenness in closed communities through a reduction in species richness and increased skew in species abundances, under all three environmental response scenarios, although autocorrelation only has a minor effect with HR. Open communities show important qualitative differences, according to changes in the correlation structure of species’ environmental responses. There is an intermediate minimum in evenness for HR communities with increasing environmental amplitude, explained by the interaction of changes in species richness and changes in the variance of within-species environmental responses across the community. Changes in autocorrelation also lead to qualitative differences between IR, CR and HR communities. Our results highlight the importance of considering mechanistically derived, hierarchical environmental correlations between species when addressing the influence of environmental variation on ecological communities, not only uniform environmental correlation across all species within a community. 相似文献
76.
Lasse N. Waehrens Christian W. Heegaard Gary E. Gilbert Jan T. Rasmussen 《The journal of histochemistry and cytochemistry》2009,57(10):907-914
Bovine lactadherin holds a stereo-specific affinity for phosphatidylserine (PS) membrane domains and binds at PS concentrations lower than the benchmark PS probe, annexin V. Accordingly, lactadherin has recognized PS exposure on preapoptotic immortalized leukemia cells at an earlier time point than has annexin V. In the present study, the cervical cancer cell line HeLa has been employed as a model system to compare the topographic distribution of PS with the two PS binding proteins as adherent cells enter the apoptotic program. HeLa cells were cultured on glass-bottom Petri dishes, and apoptosis was induced by staurosporine. Fluorescence-labeled lactadherin and/or annexin V were used to detect PS exposure by confocal microscopy. Both lactadherin and annexin V staining revealed PS localized to plasma membrane rim and blebs. In addition, lactadherin identified PS exposure on long filopodia-like extensions, whereas annexin V internalized in granule-like structures. All in all, the data further delineate the differences in PS binding patterns of lactadherin and annexin V. (J Histochem Cytochem 57:907–914, 2009) 相似文献
77.
Diversity and abundance of freshwater Actinobacteria along environmental gradients in the brackish northern Baltic Sea 总被引:1,自引:0,他引:1
Karin Holmfeldt Claudia Dziallas Josefin Titelman Kirsten Pohlmann Hans-Peter Grossart Lasse Riemann 《Environmental microbiology》2009,11(8):2042-2054
Actinobacteria are highly abundant in pelagic freshwater habitats and also occur in estuarine environments such as the Baltic Sea. Because of gradients in salinity and other environmental variables estuaries offer natural systems for examining factors that determine Actinobacteria distribution. We studied abundance and community structure of Bacteria and Actinobacteria along two transects in the northern Baltic Sea. Quantitative (CARD-FISH) and qualitative (DGGE and clone libraries) analyses of community composition were compared with environmental parameters. Actinobacteria accounted for 22–27% of all bacteria and the abundance changed with temperature. Analysis of 549 actinobacterial 16S rRNA sequences from four clone libraries revealed a dominance of the freshwater clusters ac I and ac IV, and two new subclusters ( ac I-B scB-5 and ac IV-E) were assigned. Whereas ac I was present at all stations, occurrence of ac II and ac IV differed between stations and was related to dissolved organic carbon (DOC) and chlorophyll a (Chl a ) respectively. The prevalence of the ac I-A and ac I-B subclusters changed in relation to total phosphorus (Tot-P) and Chl a respectively. Community structure of Bacteria and Actinobacteria differed between the river station and all other stations, responding to differences in DOC, Chl a and bacterial production. In contrast, the composition of active Actinobacteria (analysis based on reversely transcribed RNA) changed in relation to salinity and Tot-P. Our study suggests an important ecological role of Actinobacteria in the brackish northern Baltic Sea. It highlights the need to address dynamics at the cluster or subcluster phylogenetic levels to gain insights into the factors regulating distribution and composition of Actinobacteria in aquatic environments. 相似文献
78.
Josefin Sundin Marko Freese Lasse Marohn Tina Blancke Reinhold Hanel 《Journal of fish biology》2024,104(4):1231-1236
Juvenile specimens of the pugnose pipefish, Bryx dunckeri, were collected during a multipurpose research survey conducted within the Sargasso Sea Subtropical Convergence Zone, extending the known distribution range of this species to include open ocean areas of the Western North Atlantic. Novel spatial data are of scientific interest as information on the distribution, population structure, and population size of this species is limited. Additionally, we present detailed photographs and morphological data on the collected specimens. The results are discussed in relation to the dispersal abilities and population structure in syngnathids. 相似文献
79.
80.
Pedersen LE Harndahl M Rasmussen M Lamberth K Golde WT Lund O Nielsen M Buus S 《Immunogenetics》2011,63(12):821-834
In all vertebrate animals, CD8+ cytotoxic T lymphocytes (CTLs) are controlled by major histocompatibility complex class I (MHC-I) molecules. These are highly
polymorphic peptide receptors selecting and presenting endogenously derived epitopes to circulating CTLs. The polymorphism
of the MHC effectively individualizes the immune response of each member of the species. We have recently developed efficient
methods to generate recombinant human MHC-I (also known as human leukocyte antigen class I, HLA-I) molecules, accompanying
peptide-binding assays and predictors, and HLA tetramers for specific CTL staining and manipulation. This has enabled a complete
mapping of all HLA-I specificities (“the Human MHC Project”). Here, we demonstrate that these approaches can be applied to
other species. We systematically transferred domains of the frequently expressed swine MHC-I molecule, SLA-1*0401, onto a
HLA-I molecule (HLA-A*11:01), thereby generating recombinant human/swine chimeric MHC-I molecules as well as the intact SLA-1*0401
molecule. Biochemical peptide-binding assays and positional scanning combinatorial peptide libraries were used to analyze
the peptide-binding motifs of these molecules. A pan-specific predictor of peptide–MHC-I binding, NetMHCpan, which was originally developed to cover the binding specificities of all known HLA-I molecules, was successfully used to
predict the specificities of the SLA-1*0401 molecule as well as the porcine/human chimeric MHC-I molecules. These data indicate
that it is possible to extend the biochemical and bioinformatics tools of the Human MHC Project to other vertebrate species. 相似文献