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排序方式: 共有127条查询结果,搜索用时 15 毫秒
1.
Sophie-Marie Aicher Felix Streicher Maxime Chazal Delphine Planas Dongsheng Luo Julian Buchrieser Monika Nemcova Veronika Seidlova Jan Zukal Jordi Serra-Cobo Dominique Pontier Bertrand Pain Gert Zimmer Olivier Schwartz Philippe Roingeard Jiri Pikula Laurent Dacheux Nolwenn Jouvenet 《Journal of virology》2022,96(14)
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Summary Polyethism is a well-known phenomenon in social insects. How this phenomenon influences interactions among individuals, the spatial distribution in the nest is, on the other hand, very rarely documented. Therefore, we conducted experiments on the ant Lasius niger to observe the influence of polyethism on aggregation, by distinguishing two groups of ants: the brood-tenders and the foragers. We show a great difference in their self aggregation level. Brood-tenders are characterized by a rapid and dense gathering in one main stable cluster while foragers gather in several small unstable clusters. We show experimentally and verify with a model that this difference in behaviour is based on a smaller probability of leaving a cluster for the brood-tenders. Aggregation in the mixed case (groups composed of brood-tenders and foragers) is very close to that of the pure forager case, showing a decrease in the level of aggregation of the brood-tenders respecting to the pure group of brood-tenders. Nevertheless, experimental results supported by the results of the model, show that ants do not change their own behaviour when the two groups are together. Therefore, the decrease of the aggregation of brood-tenders in the mixed case can be explained by a difference in the dynamics between brood-tenders and foragers.Received 9 May 2003; revised 26 August 2003; accepted 1 September 2003. 相似文献
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Parental care involves elaborate behavioural interactions between parents and their offspring, with offspring stimulating their parents via begging to provision resources. Thus, begging has direct fitness benefits as it enhances offspring growth and survival. It is nevertheless subject to a complex evolutionary trajectory, because begging may serve as a means for the offspring to manipulate parents in the context of evolutionary conflicts of interest. Furthermore, it has been hypothesized that begging is coadapted and potentially genetically correlated with parental care traits as a result of social selection. Further experiments on the causal processes that shape the evolution of begging are therefore essential. We applied bidirectional artificial selection on begging behaviour, using canaries (Serinus canaria) as a model species. We measured the response to selection, the consequences for offspring development, changes in parental care traits, here the rate of parental provisioning, as well as the effects on reproductive success. After three generations of selection, offspring differed in begging behaviour according to our artificial selection regime: nestlings of the high begging line begged significantly more than nestlings of the low begging line. Intriguingly, begging less benefitted the nestlings, as reflected by on average significantly higher growth rates, and increased reproductive success in terms of a higher number of fledglings in the low selected line. Begging could thus represent an exaggerated trait, possibly because parent–offspring conflict enhanced the selection on begging. We did not find evidence that we co‐selected on parental provisioning, which may be due to the lack of power, but may also suggest that the evolution of begging is probably not constrained by a genetic correlation between parental provisioning and offspring begging. 相似文献
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Silvain Pinaud Julien Portela David Duval Fanny C. Nowacki Marie-Aude Olive Jean-Fran?ois Allienne Richard Galinier Nolwenn M. Dheilly Sylvie Kieffer-Jaquinod Guillaume Mitta André Théron Benjamin Gourbal 《PLoS pathogens》2016,12(1)
Discoveries made over the past ten years have provided evidence that invertebrate antiparasitic responses may be primed in a sustainable manner, leading to the failure of a secondary encounter with the same pathogen. This phenomenon called “immune priming” or "innate immune memory" was mainly phenomenological. The demonstration of this process remains to be obtained and the underlying mechanisms remain to be discovered and exhaustively tested with rigorous functional and molecular methods, to eliminate all alternative explanations. In order to achieve this ambitious aim, the present study focuses on the Lophotrochozoan snail, Biomphalaria glabrata, in which innate immune memory was recently reported. We provide herein the first evidence that a shift from a cellular immune response (encapsulation) to a humoral immune response (biomphalysin) occurs during the development of innate memory. The molecular characterisation of this process in Biomphalaria/Schistosoma system was undertaken to reconcile mechanisms with phenomena, opening the way to a better comprehension of innate immune memory in invertebrates. This prompted us to revisit the artificial dichotomy between innate and memory immunity in invertebrate systems. 相似文献
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Historical records and current distribution of the little fire ant,Wasmannia auropunctata Roger (Hymenoptera: Formicidae), in Gabon 下载免费PDF全文
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The human immunodeficiency virus (HIV) type-1 viral protein U (Vpu) protein enhances the release of diverse retroviruses from human, but not monkey, cells and is thought to do so by ablating a dominant restriction to particle release. Here, we determined how Vpu expression affects the subcellular distribution of HIV-1 and murine leukemia virus (MLV) Gag proteins in human cells where Vpu is, or is not, required for efficient particle release. In HeLa cells, where Vpu enhances HIV-1 and MLV release approximately 10-fold, concentrations of HIV-1 Gag and MLV Gag fused to cyan fluorescent protein (CFP) were initially detected at the plasma membrane, but then accumulated over time in early and late endosomes. Endosomal accumulation of Gag-CFP was prevented by Vpu expression and, importantly, inhibition of plasma membrane to early endosome transport by dominant negative mutants of Rab5a, dynamin, and EPS-15. Additionally, accumulation of both HIV and MLV Gag in endosomes required a functional late-budding domain. In human HOS cells, where HIV-1 and MLV release was efficient even in the absence of Vpu, Gag proteins were localized predominantly at the plasma membrane, irrespective of Vpu expression or manipulation of endocytic transport. While these data indicated that Vpu inhibits nascent virion endocytosis, Vpu did not affect transferrin endocytosis. Moreover, inhibition of endocytosis did not restore Vpu-defective HIV-1 release in HeLa cells, but instead resulted in accumulation of mature virions that could be released from the cell surface by protease treatment. Thus, these findings suggest that a specific activity that is present in HeLa cells, but not in HOS cells, and is counteracted by Vpu, traps assembled retrovirus particles at the cell surface. This entrapment leads to subsequent endocytosis by a Rab5a- and clathrin-dependent mechanism and intracellular sequestration of virions in endosomes. 相似文献
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V.?SorokerEmail author C.?Lucas T.?Simon A.?Hefetz D.?Fresneau J.?L.?Durand 《Insectes Sociaux》2003,50(3):212-217
Summary Within and between individuals hydrocarbon (HC)-circulation was studied in Pachycondyla apicalis workers, using radioactive labeling. Newly synthesized HCs occurred both in the PPG and on the epicuticle in appreciable amounts, lesser quantities were found in the crop. The front basitarsal brush contained a greater amount of radiolabeled HCs than could be predicted from its surface area, suggesting preferential secretion to these organs. We propose that the newly synthesized HCs are secreted primarily to the front basitarsal brushes and are thereafter either distributed throughout the body surface, or cleared via the PPG and the alimentary canal.Using labeled HCs as a model, we tracked the time-dependent dispersion of cuticular lipids among 11 workers, one of which was prelabeled for 24 hours. Distribution among the recipients became progressively uniform, reaching near homogenization between 5–10 days. The mean HCs transfer of P. apicalis to the PPG was substantially lower compared to that of Camponotus fellah or Aphaenogaster senilis. In contrast, transfer to the cuticle in this species was superior. We attribute the low transfer to the PPG to the inefficacy of passive body contact characteristic of P. apicalis, as opposed to trophallaxis and/or allogrooming that typify the other two species. The higher occurrence of radiolabeled HCs in P. apicalis cuticle can be attributed to their accumulation in the basitarsal brushes. The impact of cuticular lipid transfer and formation of uniform colony odour, as opposed to the maintenance of an idiosyncratic caste-specific composition, are discussed.Received 5 September 2002; revised 17 January 2003; accepted 10 February 2003. 相似文献
10.
Transport of African swine fever virus from assembly sites to the plasma membrane is dependent on microtubules and conventional kinesin 下载免费PDF全文
African swine fever virus (ASFV) is a large DNA virus that assembles in perinuclear viral factories located close to the microtubule organizing center. In this study, we have investigated the mechanism by which ASFV reaches the cell surface from the site of assembly. Immunofluorescence microscopy revealed that at 16 h postinfection, mature virions were aligned along microtubules. Furthermore, virus movement to the cell periphery was inhibited when microtubules were depolymerized by nocodazole. In addition, ASFV infection resulted in the increased acetylation of microtubules as well as their protection against depolymerization by nocodazole. Immunofluorescence microscopy showed that conventional kinesin was recruited to virus factories and to a large fraction of virus particles in the cytoplasm. Consistent with a role for conventional kinesin during ASFV egress to the cell periphery, overexpression of the cargo-binding domain of the kinesin light chain severely inhibited the movement of particles to the plasma membrane. Based on our observations, we propose that ASFV is recognized as cargo by conventional kinesin and uses this plus-end microtubule motor to move from perinuclear assembly sites to the plasma membrane. 相似文献