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991.
Britas Klemens Eriksson Tjisse van der Heide Johan van de Koppel Theunis Piersma Henk W. van der Veer Han Olff 《Ecosystems》2010,13(5):752-764
Shallow soft-sediment systems are mostly dominated by species that, by strongly affecting sediment dynamics, modify their
local environment. Such ecosystem engineering species can have either sediment-stabilizing or sediment-destabilizing effects
on tidal flats. They interplay with abiotic forcing conditions (wind, tide, nutrient inputs) in driving the community structure
and generating spatial heterogeneity, determining the composition of different communities of associated species, and thereby
affecting the channelling of energy through different compartments in the food web. This suggests that, depending on local
species composition, tidal flats may have conspicuously different geomorphology and biological functions under similar external
conditions. Here we use a historical reconstruction of benthic production in the Wadden Sea to construct a framework for the
relationships between human impacts, ecosystem engineering and sediment dynamics. We propose that increased sediment disturbances
by human exploitation interfere with biological controls of sediment dynamics, and thereby have shifted the dominant compartments
of both primary and secondary production in the Wadden Sea, transforming the intertidal from an internally regulated and spatially
heterogeneous, to an externally regulated and spatially homogenous system. This framework contributes to the general understanding
of the interaction between biological and environmental control of ecosystem functioning, and suggests a general framework
for predicting effects of human impacts on soft-bottom ecosystems. 相似文献
992.
993.
The bacterial genus Collimonas: mycophagy,weathering and other adaptive solutions to life in oligotrophic soil environments 总被引:1,自引:0,他引:1
This minireview provides a synopsis of past and present research on the biology and ecology of members of the bacterial genus Collimonas. From the distribution, abundance and functional behaviours of these so‐called collimonads emerges a general picture of bacterial adaptation to low‐nutrient soil environments. Among these adaptations is the ability to extract nutrients from living fungi (mycophagy) and from rocks and minerals (weathering). This unique combination of properties will be discussed in the context of other interactions that collimonads have with their biotic and abiotic surroundings, such as the ability to inhibit fungal growth (fungistasis), protect plant roots from fungal disease (biocontrol), and degrade natural polymers and synthetic pollutants (biodegradation). Future research on Collimonas is expected to take advantage of the genomic tools and resources that are becoming available to uncover and describe the genes and gene functions that distinguish this group of bacteria and are the basis for its phenotypes. Potential applications of collimonads include the control of unwanted fungi, for example in agriculture, their use as biological indicators of soil quality and fertility, and as a source of bioactive compounds. 相似文献
994.
Background
It is widely accepted that orthologous genes between species are conserved at the sequence level and perform similar functions in different organisms. However, the level of conservation of gene expression patterns of the orthologous genes in different species has been unclear. To address the issue, we compared gene expression of orthologous genes based on 2,557 human and 1,267 mouse samples with high quality gene expression data, selected from experiments stored in the public microarray repository ArrayExpress. 相似文献995.
Johan Grunewald Boel Brynedal Pernilla Darlington Magnus Nisell Kerstin Cederlund Jan Hillert Anders Eklund 《Respiratory research》2010,11(1):25
Background
A strong genetic influence by the MHC class II region has been reported in sarcoidosis, however in many studies with different results. This may possibly be caused by actual differences between distinct ethnic groups, too small sample sizes, or because of lack of accurate clinical subgrouping.Subjects and methods
In this study we HLA typed a large patient population (n = 754) recruited from one single centre. Patients were sub-grouped into those with Löfgren''s syndrome (LS) (n = 302) and those without (non-Löfgren''s) (n = 452), and the majority of them were clinically classified into those with recovery within two years (resolving) and those with signs of disease for more than two years (non-resolving). PCR was used for determination of HLA-DRB1 alleles. Swedish healthy blood donors (n = 1366) served as controls.Results
There was a dramatic difference in the distribution of HLA alleles in LS compared to non-LS patients (p = 4 × 10-36). Most notably, DRB1*01, DRB1*03 and DRB1*14, clearly differed in LS and non-LS patients. In relation to disease course, DRB1*07, DRB1*14 and DRB1*15 generally associated with, while DRB1*01 and DRB1*03 protected against, a non-resolving disease. Interestingly, the clinical influence of DRB1*03 (good prognosis) dominated over that of DRB1*15 (bad prognosis).Conclusions
We found several significant differences between LS and non-LS patients and we therefore suggest that genetic association studies in sarcoidosis should include a careful clinical characterisation and sub-grouping of patients, in order to reveal true genetic associations. This may be particularly accurate to do in the heterogeneous non-LS group of patients. 相似文献996.
997.
Shi Yu Tillmann Falck Anneleen Daemen Leon-Charles Tranchevent Johan AK Suykens Bart De Moor Yves Moreau 《BMC bioinformatics》2010,11(1):309
Background
This paper introduces the notion of optimizing different norms in the dual problem of support vector machines with multiple kernels. The selection of norms yields different extensions of multiple kernel learning (MKL) such as L ∞, L 1, and L 2 MKL. In particular, L 2 MKL is a novel method that leads to non-sparse optimal kernel coefficients, which is different from the sparse kernel coefficients optimized by the existing L ∞ MKL method. In real biomedical applications, L 2 MKL may have more advantages over sparse integration method for thoroughly combining complementary information in heterogeneous data sources. 相似文献998.
Garcia Collazo AM Koehler KF Garg N Färnegårdh M Husman B Ye L Ljunggren J Mellström K Sandberg J Grynfarb M Ahola H Malm J 《Bioorganic & medicinal chemistry letters》2006,16(5):1240-1244
Based on the examination of the crystal structure of rat TRbeta complexed with 3,5,3'-triiodo-l-thyronine (2) a novel TRbeta-selective indole derivative 6b was prepared and tested in vitro. This compound was found to be 14 times selective for TRbeta over TRalpha in binding and its beta-selectivity could be rationalized through the comparison of the X-ray crystallographic structures of 6b complexed with TRalpha and TRbeta. 相似文献
999.
Frédérick R Charlier C Robert S Wouters J Masereel B Pochet L 《Bioorganic & medicinal chemistry letters》2006,16(7):2017-2021
The synthesis of novel coumarins bearing on the lateral side chain in the 3-position an amine or a guanidine group is described. In vitro evaluation highlighted 14d which possesses a meta aniline side chain as a very potent THR inhibitor. Surprisingly, the introduction of a guanidine moiety always led to a decrease in THR inhibiting properties. We, thus, used docking experiments to rationalize the SAR in the series. This study showed the crucial role of a conserved water molecule in the specificity pocket of THR during docking simulation in order to explain the inactivity of guanidine derivatives. 相似文献
1000.
Michaux C Muccioli GG Lambert DM Wouters J 《Bioorganic & medicinal chemistry letters》2006,16(18):4772-4776
Substituted (thio)hydantoins (2-thioxoimidazolidinones and imidazolidinediones) were reported as new potential reversible inhibitors of fatty acid amide hydrolase (FAAH). Their binding mode to FAAH was explored to rationalize their activity and give idea to design highly active inhibitors. Starting from the crystal structure of one of these molecules, docking studies provide us with rational basis for the design of new inhibitors within the thiohydantoin family. 相似文献