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21.
Positive selection and sequence rearrangements generate extensive polymorphism in the gamete recognition protein bindin 总被引:27,自引:12,他引:15
Bindin is a gamete recognition protein of sea urchins that mediates
species-specific attachment of sperm to an egg-surface receptor during
fertilization. Sequences of bindin from closely related urchins show fixed
species-specific differences. Within species, highly polymorphic bindin
alleles result from point substitution, insertion/deletion, and
recombination. Since speciation, positive selection favoring allelic
variants has generated diversity in bindin polypeptides. Intraspecific
bindin variation can be tolerated by the egg receptor, which suggests
functional parallels between this system and other flexible recognition
systems, including immune recognition. These results show that polymorphism
in mate recognition loci required for rapid evolution of sexual isolation
can arise within natural populations.
相似文献
22.
The molecular evolution of the alcohol dehydrogenase and alcohol dehydrogenase-related genes in the Drosophila melanogaster species subgroup 总被引:5,自引:0,他引:5
The DNA sequences of the Adh genes of three members of the Drosophila
melanogaster species subgroup have been determined. This completes the Adh
sequences of the eight species of this subgroup. Two species, D. yakuba and
D. teissieri, possess processed Adh pseudogenes. In all of the species of
the subgroup, a gene of unknown function, Adhr, is located about 300 bp 3'
to Adh. Although this gene is experiencing a higher rate of synonymous
substitution than Adh, it is more constrained at the amino acid level.
Phylogenetic relationships between all eight members of the melanogaster
subgroup have been analyzed using a variety of methods. All analyses
suggested that the D. yakuba and D. teissieri pseudogenes have a single
common ancestor, rather than evolving independently in each species, and
that D. melanogaster is the sister species to D. simulans, D. sechellia,
and D. mauritiana. The evolutionary relationships of the latter three
species remain equivocal.
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23.
24.
L Alonso EC Souza MV Oliveira LFE do Nascimento PMS Dantas 《Biology of sport / Institute of Sport》2014,31(4):267-270
The objective of this study was to evaluate the genetic and environmental contribution to variation in aerobic power in monozygotic (MZ) and dizygotic (DZ) twins. The sample consisted of 20 MZ individuals (12 females and 8 males) and 16 DZ individuals (12 females and 4 males), aged from 8 to 26 years, residents in Natal, Rio Grande do Norte. The twins were assessed by a multistage fitness test. The rate of heritability found for aerobic power was 77%. Based on the results, the estimated heritability was largely responsible for the differences in aerobic power. This implies that such measures are under strong genetic influence. 相似文献
25.
Background
Endothelial permeability is involved in injury, inflammation, diabetes and cancer. It is partly regulated by the thrombin-, histamine-, and VEGF-mediated myosin-light-chain (MLC) activation pathways. While these pathways have been investigated, questions such as temporal effects and the dynamics of multi-mediator regulation remain to be fully studied. Mathematical modeling of these pathways facilitates such studies. Based on the published ordinary differential equation models of the pathway components, we developed an integrated model of thrombin-, histamine-, and VEGF-mediated MLC activation pathways.Results
Our model was validated against experimental data for calcium release and thrombin-, histamine-, and VEGF-mediated MLC activation. The simulated effects of PAR-1, Rho GTPase, ROCK, VEGF and VEGFR2 over-expression on MLC activation, and the collective modulation by thrombin and histamine are consistent with experimental findings. Our model was used to predict enhanced MLC activation by CPI-17 over-expression and by synergistic action of thrombin and VEGF at low mediator levels. These may have impact in endothelial permeability and metastasis in cancer patients with blood coagulation.Conclusion
Our model was validated against a number of experimental findings and the observed synergistic effects of low concentrations of thrombin and histamine in mediating the activation of MLC. It can be used to predict the effects of altered pathway components, collective actions of multiple mediators and the potential impact to various diseases. Similar to the published models of other pathways, our model can potentially be used to identify important disease genes through sensitivity analysis of signalling components. 相似文献26.
M. P. H. van den Broek J. E. Mhlmann B. G. S. Abeln M. Liebregts V. F. van Dijk E. M. W. van de Garde 《Netherlands heart journal》2020,28(7):406-409
In the battle against the SARS-CoV‑2 pandemic, chloroquine has emerged as a new potential therapeutic option for the treatment of infected patie 相似文献
27.
Glycosphingolipid expression in pig aorta: identification of possible target antigens for human natural antibodies 总被引:4,自引:1,他引:3
Total non-acid glycosphingolipids were isolated from the aortas of more
than 80 pigs. The glycolipids were separated by HPLC, analysed by thin-
layer chromatography, and tested for reactivity with monoclonal anti- blood
group antibodies. The fractions were structurally characterized by NMR
spectroscopy and mass spectrometry. Reactivity with both anti- blood group
A and H antibodies was seen. The major glycosphingolipid constituents were
globotri- and globotetraosylceramides and blood group H
pentaglycosylceramides based on type 1 and type 2 core saccharide chains.
Globopentaosylceramides, blood group H hexaglycosylceramides based on type
4 chain, and blood group A hexaglycosylceramides based on type 1 core chain
were also present. Two structures, that may be important targets for human
antibodies initiating hyperacute rejection following pig to human
xenotransplantation, were present as minor constituents compared to the
blood group components. These were Galalpha1,3neolactotetraosylceramide and
a Galalpha1, 3Lexstructure. A Leb/Y hexaglycosylceramide was also present.
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28.
Evert van den Broek Maurits J. J. Dijkstra Oscar Krijgsman Daoud Sie Josien C. Haan Joleen J. H. Traets Mark A. van de Wiel Iris D. Nagtegaal Cornelis J. A. Punt Beatriz Carvalho Bauke Ylstra Sanne Abeln Gerrit A. Meijer Remond J. A. Fijneman 《PloS one》2015,10(9)
Background
Cancer is caused by somatic DNA alterations such as gene point mutations, DNA copy number aberrations (CNA) and structural variants (SVs). Genome-wide analyses of SVs in large sample series with well-documented clinical information are still scarce. Consequently, the impact of SVs on carcinogenesis and patient outcome remains poorly understood. This study aimed to perform a systematic analysis of genes that are affected by CNA-associated chromosomal breaks in colorectal cancer (CRC) and to determine the clinical relevance of recurrent breakpoint genes.Methods
Primary CRC samples of patients with metastatic disease from CAIRO and CAIRO2 clinical trials were previously characterized by array-comparative genomic hybridization. These data were now used to determine the prevalence of CNA-associated chromosomal breaks within genes across 352 CRC samples. In addition, mutation status of the commonly affected APC, TP53, KRAS, PIK3CA, FBXW7, SMAD4, BRAF and NRAS genes was determined for 204 CRC samples by targeted massive parallel sequencing. Clinical relevance was assessed upon stratification of patients based on gene mutations and gene breakpoints that were observed in >3% of CRC cases.Results
In total, 748 genes were identified that were recurrently affected by chromosomal breaks (FDR <0.1). MACROD2 was affected in 41% of CRC samples and another 169 genes showed breakpoints in >3% of cases, indicating that prevalence of gene breakpoints is comparable to the prevalence of well-known gene point mutations. Patient stratification based on gene breakpoints and point mutations revealed one CRC subtype with very poor prognosis.Conclusions
We conclude that CNA-associated chromosomal breaks within genes represent a highly prevalent and clinically relevant subset of SVs in CRC. 相似文献29.
The hydrophobic effect is the main driving force in protein folding. One can estimate the relative strength of this hydrophobic effect for each amino acid by mining a large set of experimentally determined protein structures. However, the hydrophobic force is known to be strongly temperature dependent. This temperature dependence is thought to explain the denaturation of proteins at low temperatures. Here we investigate if it is possible to extract this temperature dependence directly from a large set of protein structures determined at different temperatures. Using NMR structures filtered for sequence identity, we were able to extract hydrophobicity propensities for all amino acids at five different temperature ranges (spanning 265-340 K). These propensities show that the hydrophobicity becomes weaker at lower temperatures, in line with current theory. Alternatively, one can conclude that the temperature dependence of the hydrophobic effect has a measurable influence on protein structures. Moreover, this work provides a method for probing the individual temperature dependence of the different amino acid types, which is difficult to obtain by direct experiment. 相似文献
30.
Vera Abeln Eoin MacDonald-Nethercott Maria Francesca Piacentini Romain Meeusen Jens Kleinert Heiko K. Strueder Stefan Schneider 《PloS one》2015,10(5)
IntroductionMental impairments, including deterioration of mood and cognitive performance, are known to occur during isolation and space missions, but have been insufficiently investigated. Appropriate countermeasures are required, such as exercise, which is known to prevent mood disorders for prolonged space and isolation missions. Based on the interaction of brain activity, mood and cognitive performance, this study aims to investigate the effect of long-term isolation and confinement and the long-term effect of exercise on these parameters.MethodsEight male volunteers were isolated and confined for about eight month during the winter period at the Antarctic Concordia Station. Every six weeks electroencephalographic measurements were recorded under rest conditions, and cognitive tests and a mood questionnaire were executed. Based individual training logs, subjects were afterwards separated into an active (> 2500 arbitrary training units/interval) or inactive (< 2500 arbitrary training units/interval) group.ResultsA long-term effect of exercise was observed for brain activity and mood. Regularly active people showed a decreased brain activity (alpha and beta) in the course of isolation, and steady mood. Inactive people instead first increased and than remained at high brain activity accompanied with a deterioration of mood. No effect of exercise and isolation was found for cognitive performance.ConclusionThe findings point out the positive effect of regularly performed voluntary exercise, supporting subjective mental well-being of long-term isolated people. The choice to be regularly active seems to support mental health, which is not only of interest for future isolation and space missions. 相似文献