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31.
Markus Lindholm 《Evolutionary biology》2014,41(3):503-507
The essay discusses whether biotic and abiotic environments differ in their ability to speed up or slow down morphological change and the generation of new lineages. Examples from the class Branchiopoda show that morphological conservatism is associated with enemy free space in species-poor habitats dominated by abiotic factors, while Red Queen mechanisms are predominant in larger systems with complex biotic interactions. Splitting of Branchiopod main lineages is associated with increased fish predation during the Devonian. The order Cladocera adapted and remained in larger aquatic systems, and subsequently generated a variety of new families, genera and species. The order Anostraca, on the other hand, maintained its ancestral morphology and survived only as “living fossils” in isolated ponds of harsh habitats. Despite their archaic morphology, however, they possess highly sophisticated adaptations to local physicochemical properties of their extreme environment. Hence, although morphologically conservative and possessing traits typical for “living fossils”, anostracan physiological abilities are closely adapted to the challenging and variable physicochemical conditions of ponds and ephemeral pools. 相似文献
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Adrian C. Traeger Nicholas Henschke Markus Hübscher Christopher M. Williams Steven J. Kamper Christopher G. Maher G. Lorimer Moseley James H. McAuley 《PLoS medicine》2016,13(5)
BackgroundLow back pain (LBP) is a major health problem. Globally it is responsible for the most years lived with disability. The most problematic type of LBP is chronic LBP (pain lasting longer than 3 mo); it has a poor prognosis and is costly, and interventions are only moderately effective. Targeting interventions according to risk profile is a promising approach to prevent the onset of chronic LBP. Developing accurate prognostic models is the first step. No validated prognostic models are available to accurately predict the onset of chronic LBP. The primary aim of this study was to develop and validate a prognostic model to estimate the risk of chronic LBP.ConclusionsBased on its performance in these cohorts, this five-item prognostic model for patients with acute LBP may be a useful tool for estimating risk of chronic LBP. Further validation is required to determine whether screening with this model leads to a net reduction in unnecessary interventions provided to low-risk patients. 相似文献
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Mirjam Frischknecht Vidhya Jagannathan Philippe Plattet Markus Neuditschko Heidi Signer-Hasler Iris Bachmann Alicja Pacholewska Cord Dr?gemüller Elisabeth Dietschi Christine Flury Stefan Rieder Tosso Leeb 《PloS one》2015,10(10)
The identification of quantitative trait loci (QTL) such as height and their underlying causative variants is still challenging and often requires large sample sizes. In humans hundreds of loci with small effects control the heritable portion of height variability. In domestic animals, typically only a few loci with comparatively large effects explain a major fraction of the heritability. We investigated height at withers in Shetland ponies and mapped a QTL to ECA 6 by genome-wide association (GWAS) using a small cohort of only 48 animals and the Illumina equine SNP70 BeadChip. Fine-mapping revealed a shared haplotype block of 793 kb in small Shetland ponies. The HMGA2 gene, known to be associated with height in horses and many other species, was located in the associated haplotype. After closing a gap in the equine reference genome we identified a non-synonymous variant in the first exon of HMGA2 in small Shetland ponies. The variant was predicted to affect the functionally important first AT-hook DNA binding domain of the HMGA2 protein (c.83G>A; p.G28E). We assessed the functional impact and found impaired DNA binding of a peptide with the mutant sequence in an electrophoretic mobility shift assay. This suggests that the HMGA2 variant also affects DNA binding in vivo and thus leads to reduced growth and a smaller stature in Shetland ponies. The identified HMGA2 variant also segregates in several other pony breeds but was not found in regular-sized horse breeds. We therefore conclude that we identified a quantitative trait nucleotide for height in horses. 相似文献
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The inactivation of Bacillus subtilis spores during long-term exposure (up to several months) to extreme dryness (especially vacuum) is strain-dependent, through only to a small degree. During a first phase (lasting about four days) monolayers of spores lose about 20% of their viability, regardless of the strain studied. During this phase loss in viability can be equally attributed both to damages of hydrophobic structures (membranes and proteins) and DNA. During a second phase lasting for the remaining time of experimental observation (weeks, months and years) the loss in viability is slowed. A viability of 55% to 75% (depending on the strain) is attained after a total exposure of 36 days. The loss in viability during the second phase can be correlated with the occurrence of DNA double strand breaks. Also covalent DNA-protein cross-links are formed by vacuum exposure. If the protein moiety of these cross-links is degraded by proteinase K-treatment in vitro additional DNA double strand breaks result. The data are also discussed with respect to survival on Mars and in near Earth orbits. 相似文献
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Schuster Martina Tewary Gargi Bao Xuanwen Subedi Prabal Hauck Stefanie M. Olsen Ann Karin Eide Dag Markus Trott Klaus Rüdiger Götz Sebastian Atkinson Michael J. Rosemann Michael 《Radiation and environmental biophysics》2021,60(4):689-689
Radiation and Environmental Biophysics - 相似文献