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91.
Background
The genetic architecture of a quantitative trait influences the phenotypic response to natural or artificial selection. One of the main objectives of genetic mapping studies is to identify the genetic factors underlying complex traits and understand how they contribute to phenotypic expression. Presently, we are good at identifying and locating individual loci with large effects, but there is a void in describing more complex genetic architectures. Although large networks of connected genes have been reported, there is an almost complete lack of information on how polymorphisms in these networks contribute to phenotypic variation and change. To date, most of our understanding comes from theoretical, model-based studies, and it remains difficult to assess how realistic their conclusions are as they lack empirical support. 相似文献92.
Khayath N Vicogne J Ahier A BenYounes A Konrad C Trolet J Viscogliosi E Brehm K Dissous C 《The FEBS journal》2007,274(3):659-676
Insulin signalling is a very ancient and well conserved pathway in metazoan cells, dependent on insulin receptors (IR) which are transmembrane proteins with tyrosine kinase activity. A unique IR is usually present in invertebrates whereas two IR members are found with different functions in vertebrates. This work demonstrates the existence of two distinct IR homologs (SmIR-1 and SmIR-2) in the parasite trematode Schistosoma mansoni. These two receptors display differences in several structural motifs essential for signalling and are differentially expressed in parasite tissues, suggesting that they could have distinct functions. The gene organization of SmIR-1 and SmIR-2 is similar to that of the human IR and to that of the IR homolog from Echinococcus multilocularis (EmIR), another parasitic platyhelminth. SmIR-1 and SmIR-2 were shown to interact with human pro-insulin but not with pro-insulin-like growth factor-1 in two-hybrid assays. Phylogenetic results indicated that SmIR-2 and EmIR might be functional orthologs whereas SmIR-1 would have emerged to fulfil specific functions in schistosomes. 相似文献
93.
Mechanisms of leukemogenesis induced by bovine leukemia virus: prospects for novel anti-retroviral therapies in human 总被引:1,自引:0,他引:1
Nicolas Gillet Arnaud Florins Mathieu Boxus Catherine Burteau Annamaria Nigro Fabian Vandermeers Hervé Balon Amel-Baya Bouzar Julien Defoiche Arsène Burny Michal Reichert Richard Kettmann Luc Willems 《Retrovirology》2007,4(1):1-32
In 1871, the observation of yellowish nodules in the enlarged spleen of a cow was considered to be the first reported case of bovine leukemia. The etiological agent of this lymphoproliferative disease, bovine leukemia virus (BLV), belongs to the deltaretrovirus genus which also includes the related human T-lymphotropic virus type 1 (HTLV-1). This review summarizes current knowledge of this viral system, which is important as a model for leukemogenesis. Recently, the BLV model has also cast light onto novel prospects for therapies of HTLV induced diseases, for which no satisfactory treatment exists so far. 相似文献
94.
Brandler S Lucas-Hourani M Moris A Frenkiel MP Combredet C Février M Bedouelle H Schwartz O Desprès P Tangy F 《PLoS neglected tropical diseases》2007,1(3):e96
Dengue disease is an increasing global health problem that threatens one-third of the world's population. Despite decades of efforts, no licensed vaccine against dengue is available. With the aim to develop an affordable vaccine that could be used in young populations living in tropical areas, we evaluated a new strategy based on the expression of a minimal dengue antigen by a vector derived from pediatric live-attenuated Schwarz measles vaccine (MV). As a proof-of-concept, we inserted into the MV vector a sequence encoding a minimal combined dengue antigen composed of the envelope domain III (EDIII) fused to the ectodomain of the membrane protein (ectoM) from DV serotype-1. Immunization of mice susceptible to MV resulted in a long-term production of DV1 serotype-specific neutralizing antibodies. The presence of ectoM was critical to the immunogenicity of inserted EDIII. The adjuvant capacity of ectoM correlated with its ability to promote the maturation of dendritic cells and the secretion of proinflammatory and antiviral cytokines and chemokines involved in adaptive immunity. The protective efficacy of this vaccine should be studied in non-human primates. A combined measles-dengue vaccine might provide a one-shot approach to immunize children against both diseases where they co-exist. 相似文献
95.
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97.
Chêne A Donati D Guerreiro-Cacais AO Levitsky V Chen Q Falk KI Orem J Kironde F Wahlgren M Bejarano MT 《PLoS pathogens》2007,3(6):e80
Although malaria and Epstein-Barr (EBV) infection are recognized cofactors in the genesis of endemic Burkitt lymphoma (BL), their relative contribution is not understood. BL, the most common paediatric cancer in equatorial Africa, is a high-grade B cell lymphoma characterized by c-myc translocation. EBV is a ubiquitous B lymphotropic virus that persists in a latent state after primary infection, and in Africa, most children have sero-converted by 3 y of age. Malaria infection profoundly affects the B cell compartment, inducing polyclonal activation and hyper-gammaglobulinemia. We recently identified the cystein-rich inter-domain region 1alpha (CIDR1alpha) of the Plasmodium falciparum membrane protein 1 as a polyclonal B cell activator that preferentially activates the memory compartment, where EBV is known to persist. Here, we have addressed the mechanisms of interaction between CIDR1alpha and EBV in the context of B cells. We show that CIDR1alpha binds to the EBV-positive B cell line Akata and increases the number of cells switching to the viral lytic cycle as measured by green fluorescent protein (GFP) expression driven by a lytic promoter. The virus production in CIDR1alpha-exposed cultures was directly proportional to the number of GFP-positive Akata cells (lytic EBV) and to the increased expression of the EBV lytic promoter BZLF1. Furthermore, CIDR1alpha stimulated the production of EBV in peripheral blood mononuclear cells derived from healthy donors and children with BL. Our results suggest that P. falciparum antigens such as CIDR1alpha can directly induce EBV reactivation during malaria infection that may increase the risk of BL development for children living in malaria-endemic areas. To our knowledge, this is the first report to show that a microbial protein can drive a latently infected B cell into EBV replication. 相似文献
98.
Assessing whether trait variations among individuals are consistent over time and among environmental conditions is crucial to understand evolutionary responses to new selective pressures such as climate change. According to the universal thermal dependence hypothesis, thermal sensitivity of metabolic rate should not vary strongly and consistently among organisms, implying limited evolutionary response for metabolic traits under climate change. However, this hypothesis has been rarely tested at an individual level, leaving a gap in our understanding of climate change impacts on metabolic responses and their potential evolution. Using the amphipod Gammarus fossarum, we investigated the variability and repeatability of individual metabolic thermal reaction norms over time. We found large variations in both the thermal sensitivity (i.e. slope) and expression level (i.e. intercept) of individual metabolic reaction norms. Moreover, differences among individuals were consistent over time, and therefore repeatable. Inter‐individual variations in body mass resulted in a high repeatability of metabolic expression level but had no significant effect on the repeatability of thermal sensitivity. Overall, our results highlight that inter‐individual variability and repeatability of thermal reaction norms can be substantial. We conclude that these consistent differences among individuals should not be overlooked when apprehending the ecological and evolutionary effects of climate change. 相似文献
99.
Length–weight relationship of thirteen demersal fishes from the tropical Brazilian continental shelf
Leandro N. Eduardo Thierry Frdou Alex S. Lira Lucas V. S. Silva Beatrice P. Ferreira Arnaud Bertrand Frdric Mnard Flvia Lucena-Frdou 《Zeitschrift fur angewandte Ichthyologie》2019,35(2):590-593
This study provides the length‐weight relationship (LWR) for 13 demersal fish species belonging to 11 families and 8 orders. Data were collected in the northeast Brazilian continental shelf during two scientific surveys (2015 and 2017) using a bottom trawl net (side length of body mesh: 40 mm, side length of cod‐end mesh: 25 mm) at 35 stations between 15 and 60 m of depth. We provide novel LWRs for four species and expand the size range of 9 relationships previously established. 相似文献
100.
Arnaud Di Franco Denis Baurain Gernot Glckner Michael Melkonian Herv Philippe 《Molecular biology and evolution》2022,39(1)
It is commonly assumed that increasing the number of characters has the potential to resolve evolutionary radiations. Here, we studied photosynthetic stramenopiles (Ochrophyta) using alignments of heterogeneous origin mitochondrion, plastid, and nucleus. Surprisingly while statistical support for the relationships between the six major Ochrophyta lineages increases when comparing the mitochondrion (6,762 sites) and plastid (21,692 sites) trees, it decreases in the nuclear (209,105 sites) tree. Statistical support is not simply related to the data set size but also to the quantity of phylogenetic signal available at each position and our ability to extract it. Here, we show that this ability for current phylogenetic methods is limited, because conflicting results were obtained when varying taxon sampling. Even though the use of a better fitting model improved signal extraction and reduced the observed conflicts, the plastid data set provided higher statistical support for the ochrophyte radiation than the larger nucleus data set. We propose that the higher support observed in the plastid tree is due to an acceleration of the evolutionary rate in one short deep internal branch, implying that more phylogenetic signal per position is available to resolve the Ochrophyta radiation in the plastid than in the nuclear data set. Our work therefore suggests that, in order to resolve radiations, beyond the obvious use of data sets with more positions, we need to continue developing models of sequence evolution that better extract the phylogenetic signal and design methods to search for genes/characters that contain more signal specifically for short internal branches. 相似文献