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61.
62.
Marie-Jeanne Holveck Katharina Riebel 《Proceedings. Biological sciences / The Royal Society》2010,277(1678):153-160
Mate choice studies routinely assume female preferences for indicators of high quality in males but rarely consider developmental causes of within-population variation in mating preferences. By contrast, recent mate choice models assume that costs and benefits of searching or competing for high-quality males depend on females'' phenotypic quality. A prediction following from these models is that manipulation of female quality should alter her choosiness or even the direction of her mating preferences. We here provide (to our knowledge) the first example where an experimental manipulation of female quality induced a mating preference for low-quality males. Zebra finches (Taeniopygia guttata) reared in small or large experimental broods became high- or low-quality adults, respectively. Only high-quality females preferred high-quality males'' mate-advertising songs, while all low-quality females preferred low-quality males'' song. Subsequent breeding trials confirmed this pattern: latency until egg laying was shortest in quality-matched pairs, indicating that quality-matched birds were accepted faster as partners. Females produced larger eggs when mated with high-quality males, regardless of their own quality, indicating consensus regarding male quality despite the expression of different choices. Our results demonstrate the importance of considering the development of mating preferences to understand their within-population variation and environmentally induced change. 相似文献
63.
Julien Lefèvre Philippe Savarin Pierre Gans Lo?c Hamon Marie-Jeanne Clément Marie-Odile David Christophe Bosc Annie Andrieux Patrick A. Curmi 《The Journal of biological chemistry》2013,288(34):24910-24922
Microtubules are highly dynamic αβ-tubulin polymers. In vitro and in living cells, microtubules are most often cold- and nocodazole-sensitive. When present, the MAP6/STOP family of proteins protects microtubules from cold- and nocodazole-induced depolymerization but the molecular and structure determinants by which these proteins stabilize microtubules remain under debate. We show here that a short protein fragment from MAP6-N, which encompasses its Mn1 and Mn2 modules (MAP6(90–177)), recapitulates the function of the full-length MAP6-N protein toward microtubules, i.e. its ability to stabilize microtubules in vitro and in cultured cells in ice-cold conditions or in the presence of nocodazole. We further show for the first time, using biochemical assays and NMR spectroscopy, that these effects result from the binding of MAP6(90–177) to microtubules with a 1:1 MAP6(90–177):tubulin heterodimer stoichiometry. NMR data demonstrate that the binding of MAP6(90–177) to microtubules involve its two Mn modules but that a single one is also able to interact with microtubules in a closely similar manner. This suggests that the Mn modules represent each a full microtubule binding domain and that MAP6 proteins may stabilize microtubules by bridging tubulin heterodimers from adjacent protofilaments or within a protofilament. Finally, we demonstrate that Ca2+-calmodulin competes with microtubules for MAP6(90–177) binding and that the binding mode of MAP6(90–177) to microtubules and Ca2+-calmodulin involves a common stretch of amino acid residues on the MAP6(90–177) side. This result accounts for the regulation of microtubule stability in cold condition by Ca2+-calmodulin. 相似文献
64.
Dianne L Perrot-Minnot MJ Bauer A Gaillard M Léger E Rigaud T 《Evolution; international journal of organic evolution》2011,65(9):2692-2698
Many trophically transmitted parasites with complex life cycles manipulate their intermediate host behavior in ways facilitating their transmission to final host by predation. This facilitation generally results from lowering host's antipredatory defenses when the parasite is infective to the final host. However, a recent theoretical model predicts that an optimal parasitic strategy would be to protect the intermediate host from predation when noninfective, before switching to facilitation when the infective stage is reached. We tested this hypothesis in the fish acanthocephalan parasite Pomphorhynchus laevis using the amphipod Gammarus pulex as intermediate host. Gammarids parasitized by noninfective stage of P. laevis (acanthella) hid significantly more under refuges than uninfected ones. In addition, acanthella-infected gammarids were less predated upon by trout than uninfected ones. As predicted, a switch toward decreased antipredatory behavior of G. pulex and enhanced vulnerability to predation was found when P. laevis reached the stage infective to its final host. The parasites appear to be able to exploit plasticity in host antipredatory responses, and shift the host optimal response toward their own optimal balance. 相似文献
65.
Drosophila melanogaster adapt their food consumption to their internal needs and avoid ingesting noxious molecules. Defects in the genes involved in these decisions induce behavioral alterations that are usually screened by monitoring flies feeding in 2-choice or in no-choice situations. Here, we introduce a new behavioral test in which groups of flies are given access to 6 capillary feeders (MultiCAFE) containing fructose mixed with a serial dilution of a test substance. Using quinine, we first showed that fly density, distance between capillaries, and order of presentation have a minor impact on the discrimination performances of the flies. Fly discrimination was also only marginally affected by the type of test (no-choice, binary, or multiple-choice). Interestingly, the feeding reduction was well correlated with a reduction of the firing elicited by the mixture in sugar-sensitive gustatory receptor neurons, suggesting that several mechanisms concur to allow flies to make their choices. In addition to quinine, flies exhibited marked dose-dependent aversions to the consumption of berberine, caffeine, lobeline, nicotine, papaverine, strychnine, and theophylline, which all taste bitter to humans. Thus, despite of the multiplicity of choices available, flies consistently avoid alkaloids mixed with a sugar solution, and their choices are strongly dependent on their taste system. The MultiCAFE assay represents an interesting alternative to other feeding tests, in that it allows monitoring of the absolute consumption while also requiring less flies and time to run than other assays. 相似文献
66.
Marie-Laure Hourdou Colette Duez Bernard Joris Marie-Jeanne Vacheron Micheline Guinand Georges Michel Jean-Marie Ghuysen 《FEMS microbiology letters》1992,91(2):165-170
The gene encoding the Bacillus sphaericus gamma-D-glutamyl-L-diamino acid endopeptidase II, a cytoplasmic enzyme involved in cell sporulation [1], contains the information for a 271-amino acid protein devoid of a signal peptide. The endopeptidase lacks sequence relatedness with other proteins of known primary structure except that its C-terminal region has significant similarity with the C-terminal region of the 54-kDa P54 protein of Enterococcus faecium, of unknown function [2]. 相似文献
67.
Zahur Zaman Marie-Jeanne Heynen Robrecht L. Verwilghen 《Biochimica et Biophysica Acta (BBA)/General Subjects》1980,632(4):553-561
Mechanism of transferrin iron uptake by rat reticulocytes was studied using 59Fe- and 125I-labelled rat transferrin. Whereas more than 80% of the reticulocyte-bound 59Fe was located in the cytoplasmic fraction, only 25–30% of 125I-labelled transferrin was found inside the cells. As shown by the presence of acetylcholine esterase, 10–15% of the cytoplasmic 125I-labelled transferrin might have been derived from the contamination of this fraction by the plasma membrane fragments. Electron microscopic autoradiography indicated 26% of the cell-bound 125I-labelled transferrin to be inside the reticulocytes. Both the electron microscopic and biochemical studies showed that the rat reticulocytes endocytosed their plasma membrane independently of transferrin. Sepharose-linked transferrin was found to be capable of delivering 59Fe to the reticulocytes. Our results suggest that penetration of the cell membrane by transferrin is not necessary for the delivery of iron and that, although it might make a contribution to the cellular iron uptake, internalization of transferrin reflects endocytotic activity of the reticulocyte cell membrane. 相似文献
68.
Optimisation of the post-validation process: the report and recommendations of ECVAM Workshop 67 总被引:1,自引:0,他引:1
69.
Diana J Persat F Staquet MJ Assossou O Ferrandiz J Gariazzo MJ Peyron F Picot S Schmitt D Vincent C 《FEMS immunology and medical microbiology》2004,42(3):321-331
Migration and maturation of human dendritic cells derived from CD34+ progenitor cells (DC) infected by Toxoplasma gondii were studied in an in vitro model. We demonstrated that infection with virulent type I strains RH and ENT or type II low virulent strains PRU and CAL induced DC migration towards MIP-3beta. However, type II strains induced a higher percentage of migrating cells than that induced by type I strains or positive controls (chemical allergen or lipopolysaccharides). Type II strains produced soluble factors responsible of the high migration whereas heat killed tachyzoites did not induced a migration higher than positive controls. We also demonstrated that infection by virulent strains and not by type II stains or heat killed tachyzoites triggers DC maturation. A soluble factor released by type II strains was responsible of the absence of DC maturation. Taken together, these results demonstrated that the interference of T. gondii in the behaviour of DC functions is related to the strain types and can be supported by secretion of soluble factors by the parasite. 相似文献
70.
Godefroy S Corvaia N Schmitt D Aubry JP Bonnefoy JY Jeannin P Staquet MJ 《European journal of cell biology》2003,82(4):193-200
Outer membrane protein (Omp)A is highly represented and conserved in the Enterobacteriaceae family. Using a recombinant OmpA from Klebsiella pneumoniae (kpOmpA), we have analysed the interaction between this bacterial cell wall protein and human Langerhans cells (LC), the antigen-presenting cells of the epidermis and mucosa. We showed that biotinylated kpOmpA binds to human LC freshly isolated from epidermis. kpOmpA up-regulated MHC class II, CD86 and CCR7 expression, enhanced migration in response to macrophage inflammatory protein-3beta (MIP-3beta) through a reconstituted basement membrane mimicking the prerequisite passage through the dermal-epidermal basement membrane on the way to lymph nodes. The allostimulatory function of kpOmpA-treated LC was more potent than that of untreated cells. Even though the proportion of LC which binds kpOmpA was shown to vary between individuals, our data indicate that kpOmpA binds to and activates LC, and suggest that recognition of OmpA by LC may be an initiating event in the antibacterial host response. 相似文献