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Association of vinculin to the platelet cytoskeleton during thrombin-induced aggregation 总被引:4,自引:0,他引:4
Vinculin is a protein generally believed to be involved in membrane-cytoskeleton interaction, and its presence in platelets has been verified earlier. Here we show that in resting bovine platelets, vinculin is not associated with the Triton-insoluble cytoskeletal fraction but becomes incorporated into it during the thrombin-induced activation process. The incorporation starts around the same time as the release reaction and only after the shape change and the first phase of aggregation have taken place. Its time course parallels the cytoskeletal association of actin and certain other contractile proteins. Vinculin is a minor component of platelet cytoskeleton and only about 10% of the total platelet vinculin becomes incorporated into the Triton X-100 residue. 相似文献
3.
Agatha Livin‐Bazin Maxime Pineaux Mathilde Le Covec Manfred Gahr Dalila Bovet Auguste M. P. von Bayern 《Ethology : formerly Zeitschrift fur Tierpsychologie》2019,125(5):276-288
Food sharing has attracted much attention because of its apparently altruistic nature and its link to prosociality. However, food sharing has been mostly studied in a reproductive context, during courtship and parental care, where the fitness benefits are obvious. We still lack a clear understanding of the functions of food sharing outside any reproductive context and within social groups of same‐aged peers. Previous studies suggest that cofeeding, the action to let another animal feed from the same monopolizable food source, may be used to build and strengthen bonds between individuals. This may be particularly crucial in social birds forming long‐term associations between mates or siblings such as psittacids and corvids. Here, we investigated food sharing and affiliative behaviors such as allopreening in a psittacine species, namely in a group of captive juvenile cockatiels (Nymphicus hollandicus) consisting of five siblings and five unrelated birds. Our main objective was to study the developmental pattern of food sharing over time and its implication in social bonding depending on kinship, affiliation, and sex. Studying cockatiels in this context is providing many new information since most of the studies on food sharing in birds focused on corvids. We found that, contrary to jackdaws, cockatiels continued to share food with multiple individuals, although the frequency of cofeeding as well as the number of cofeeding partners decreased over time. Cockatiels shared more food with their siblings than with other conspecifics but they were not more likely to do cofeeding with birds of the opposite sex. We also found evidence that young cockatiels exchanged more food with those from whom they received food (reciprocity) and, to a lesser extent, allopreening (interchange), than from other cockatiels. Our findings suggest that in cockatiels, food sharing within social groups serves the formation (and maintenance) of affiliative bonds, especially between siblings, rather than pair bonds, but might additionally be explained by reciprocity, interchange, and harassment avoidance. 相似文献
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Regulation of vascular development by fibroblast growth factors 总被引:5,自引:0,他引:5
Fibroblast growth factors (FGFs) are potent stimulators of angiogenesis in vitro and in vivo. However, the precise role of FGFs and vascular development in normal and pathological tissue has long remained ill defined. Recently, substantial progress has been made toward a better understanding of their role. Genetic studies in mice or in culture systems indicate a role for FGFs in vessel assembly and sprouting. FGFs also stimulate blood vessel branching and lymphangiogenesis. The molecular mechanisms by which FGFs mediate angiogenesis are also better understood. Finally, the FGF/FGF-receptor system has become a focus for the development of novel therapeutic strategies for the treatment of angiogenesis-related diseases such as tissue ischemia.Work described herein from our laboratory was supported by grants from the Ligue Nationale contre le Cancer, the Association de la Recherche sur le Cancer, Rétina France, the Institut National de la Santé et de la Recherche Médicale (INSERM), and the Ministère de la Recherche 相似文献
6.
Hung CS Bouckaert J Hung D Pinkner J Widberg C DeFusco A Auguste CG Strouse R Langermann S Waksman G Hultgren SJ 《Molecular microbiology》2002,44(4):903-915
The first step in the colonization of the human urinary tract by pathogenic Escherichia coli is the mannose-sensitive binding of FimH, the adhesin present at the tip of type 1 pili, to the bladder epithelium. We elucidated crystallographically the interactions of FimH with D-mannose. The unique site binding pocket occupied by D-mannose was probed using site-directed mutagenesis. All but one of the mutants examined had greatly diminished mannose-binding activity and had also lost the ability to bind human bladder cells. The binding activity of the mono-saccharide D-mannose was delineated from this of mannotriose (Man(alpha 1-3)[Man(alpha 1-6)]Man) by generating mutants that abolished D-mannose binding but retained mannotriose binding activity. Our structure/function analysis demonstrated that the binding of the monosaccharide alpha-D-mannose is the primary bladder cell receptor for uropathogenic E. coli and that this event requires a highly conserved FimH binding pocket. The residues in the FimH mannose-binding pocket were sequenced and found to be invariant in over 200 uropathogenic strains of E. coli. Only enterohaemorrhagic E. coli (EHEC) possess a sequence variation within the mannose-binding pocket of FimH, suggesting a naturally occurring mechanism of attenuation in EHEC bacteria that would prevent them from being targeted to the urinary tract. 相似文献
7.
Taillades Jacques Beuzelin Isabelle Garrel Laurence Tabacik Vlado Bied Catherine Commeyras Auguste 《Origins of life and evolution of the biosphere》1998,28(1):61-77
Our previous kinetic and thermodynamic studies upon the reactional system HCHO/HCN/ NH3 in aqueous solutions are completed. In the assumed prebiotic conditions of the primitive earth ([HCHO] and [HCN] near 1 g L–1, T = 25 °C, pH = 8, [NH3] very low), this system leads to 99.9% of -hydroxyacetonitrile and 0.1% of -aminoacetonitrile (precursor of the -amino acid). The classical base-catalyzed hydration of nitriles, slow and not selective, can not modify significantly this proportion. On the contrary, we found two specific and efficient reactions of -aminonitriles which shift the initial equilibrium in favor of the -aminonitrile pathway. The first reaction catalyzed by formaldehyde generates -aminoamides, precursors of -aminoacids. The second reaction catalyzed by carbon dioxide affords hydantoins, precursors of N-carbamoyl--aminoacids. In the primitive hydrosphere, where the concentration in carbon dioxide was estimated to be higher than that of formaldehyde, the formation of hydantoins was consequently more efficient. The rates of hydrolysis of the -aminoacetamide and of the hydantoin at pH 8 being very similar, the synthesis of the N-carbamoyl--amino acid seems then to be the fatal issue of the HCHO/HCN/NH3 system that nature used to perform its evolution. These N-protected -amino acids offer new perspectives in prebiotic chemistry, in particular for the emergence of peptides on the prebiotic earth. 相似文献
8.
Marie Collet Isabelle Amat Sandrine Sauzet Alexandra Auguste Xavier Fauvergue Laurence Mouton Emmanuel Desouhant 《Molecular ecology》2020,29(3):596-609
Sib‐mating avoidance is a pervasive behaviour that is expected to evolve in species subject to inbreeding depression. Although laboratory studies provide elegant demonstrations, small‐scaled bioassays minimize the costs of mate finding and choice, and thus may produce spurious findings. We therefore combined laboratory experiments with field observations to examine the existence of inbreeding avoidance using the parasitoid wasp Venturia canescens. In the laboratory, our approach consisted of mate‐choice experiments to assess kin discrimination in population cages with competitive interactions. A higher mating probability after sib rejections suggested that females could discriminate their sibs; however, in contrast to previous findings, sib‐mating avoidance was not observed. To compare our laboratory results to field data, we captured 241 individuals from two populations. Females laid eggs in the lab, and 226 daughters were obtained. All individuals were genotyped at 18 microsatellite loci, which allowed inference of the genotype of each female's mate and subsequently the relatedness within each mating pair. We found that the observed rate of sib‐mating did not differ from the probability that sibs encountered one another at random in the field, which is consistent with an absence of sib‐mating avoidance. In addition, we detected a weak but significant male‐biased dispersal, which could reduce encounters between sibs. We also found weak fitness costs associated with sib‐mating. As such, the sex‐biased dispersal that we found is probably sufficient to mitigate these costs. These results imply that kin discrimination has probably evolved for purposes other than mate choice, such as superparasitism avoidance. 相似文献
9.
Genovesio A Kwon YJ Windisch MP Kim NY Choi SY Kim HC Jung S Mammano F Perrin V Boese AS Casartelli N Schwartz O Nehrbass U Emans N 《Journal of biomolecular screening》2011,16(9):945-958
Recent genome-wide RNAi screens have identified >842 human genes that affect the human immunodeficiency virus (HIV) cycle. The list of genes implicated in infection differs between screens, and there is minimal overlap. A reason for this variance is the interdependence of HIV infection and host cell function, producing a multitude of indirect or pleiotropic cellular effects affecting the viral infection during RNAi screening. To overcome this, the authors devised a 15-dimensional phenotypic profile to define the viral infection block induced by CD4 silencing in HeLa cells. They demonstrate that this phenotypic profile excludes nonspecific, RNAi-based side effects and viral replication defects mediated by silencing of housekeeping genes. To achieve statistical robustness, the authors used automatically annotated RNAi arrays for seven independent genome-wide RNAi screens. This identified 56 host genes, which reliably reproduced CD4-like phenotypes upon HIV infection. The factors include 11 known HIV interactors and 45 factors previously not associated with HIV infection. As proof of concept, the authors confirmed that silencing of PAK1, Ku70, and RNAseH2A impaired HIV replication in Jurkat cells. In summary, multidimensional, visual profiling can identify genes required for HIV infection. 相似文献
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