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991.
Romain Fougeyrollas Klára Dolej?ová David Sillam-Dussès Virginie Roy Chantal Poteaux Robert Hanus Yves Roisin 《Proceedings. Biological sciences / The Royal Society》2015,282(1809)
Asexual queen succession (AQS), in which workers, soldiers and dispersing reproductives are produced sexually while numerous non-dispersing queens arise through thelytokous parthenogenesis, has recently been described in three species of lower termites of the genus Reticulitermes. Here, we show that AQS is not an oddity restricted to a single genus of lower termites, but a more widespread strategy occurring also in the most advanced termite group, the higher termites (Termitidae). We analysed the genetic structure in 10 colonies of the Neotropical higher termite Embiratermes neotenicus (Syntermitinae) using five newly developed polymorphic microsatellite loci. The colonies contained one primary king accompanied either by a single primary queen or by up to almost 200 neotenic queens. While the workers, the soldiers and most future dispersing reproductives were produced sexually, the non-dispersing neotenic queens originated through thelytokous parthenogenesis of the founding primary queen. Surprisingly, the mode of thelytoky observed in E. neotenicus is most probably automixis with central fusion, contrasting with the automixis with terminal fusion documented in Reticulitermes. The occurrence of AQS based on different mechanisms of ploidy restoration raises the hypothesis of an independent evolutionary origin of this unique reproductive strategy in individual lineages of lower and higher termites. 相似文献
992.
Development of two major resources for pea genomics: the GenoPea 13.2K SNP Array and a high‐density,high‐resolution consensus genetic map 下载免费PDF全文
Nadim Tayeh Christelle Aluome Matthieu Falque Françoise Jacquin Anthony Klein Aurélie Chauveau Aurélie Bérard Hervé Houtin Céline Rond Jonathan Kreplak Karen Boucherot Chantal Martin Alain Baranger Marie‐Laure Pilet‐Nayel Thomas D. Warkentin Dominique Brunel Pascal Marget Marie‐Christine Le Paslier Grégoire Aubert Judith Burstin 《The Plant journal : for cell and molecular biology》2015,84(6):1257-1273
993.
994.
RNA silencing functions as an antiviral defense through the action of DICER-like (DCL) and ARGONAUTE (AGO) proteins. In turn, plant viruses have evolved strategies to counteract this defense mechanism, including the expression of suppressors of RNA silencing. Potato virus X (PVX) does not systemically infect Arabidopsis thaliana Columbia-0, but is able to do so effectively in mutants lacking at least two of the four Arabidopsis DCL proteins. PVX can also infect Arabidopsis ago2 mutants, albeit less effectively than double DCL mutants, suggesting that additional AGO proteins may mediate anti-viral defenses. Here we show, using functional assays, that all Arabidopsis AGO proteins have the potential to target PVX lacking its viral suppressor of RNA silencing (VSR), P25, but that only AGO2 and AGO5 are able to target wild-type PVX. However, P25 directly affects only a small subset of AGO proteins, and we present evidence indicating that its protective effect is mediated by precluding AGO proteins from accessing viral RNA, as well as by directly inhibiting the RNA silencing machinery. In agreement with functional assays, we show that Potexvirus infection induces AGO5 expression and that both AGO2 and AGO5 are required for full restriction of PVX infection in systemic tissues of Arabidopsis. 相似文献
995.
Evelyne Poli Amandine Magnaudeix Chantal Damia Fabrice Lalloué Vincent Chaleix Eric Champion Vincent Sol 《Bioorganic & medicinal chemistry letters》2019,29(9):1069-1073
To bring osteoinductive properties to calcium phosphate (CaP) bioceramics, a silicon-substituted hydroxyapatite was functionalized by integrin-adhesive cyclic-pentapeptides (c-(DfKRG)). A new two-step protocol was set up to immobilize peptides at low and controlled density on the ceramic surface and limit contamination by adsorbed molecules. To this aim, a spacer bearing c-(DfKRG)-S-PEG6-NHS molecule was synthesized and bonded to an organosilane previously covalently bonded to the ceramic surface. The functionalized ceramic was tested in vitro for MC3T3-E1 murine pre-osteoblasts. CaP ceramic surface retained good biological properties thanks to low density of bonded molecules preserving part of the bioactive CaP surface free of bioorganic molecules. The final SiHA-T-PEG6-S-c-(DfKRG) was shown to increase cell density and to improve proliferation. Furthermore, the use of a strong and stable covalent bond between inorganic and organic parts prevented early burst release of the peptide and increased the persistence of its bioactivity over time. So, this CaP ceramic associating c-(DfKRG) by covalent grafting could be considered as promising new biomaterials for bone tissue engineering. 相似文献
996.
Arrigo AP Simon S Gibert B Kretz-Remy C Nivon M Czekalla A Guillet D Moulin M Diaz-Latoud C Vicart P 《FEBS letters》2007,581(19):3665-3674
Hsp27 and alphaB-crystallin are molecular chaperones that are constitutively expressed in several mammalian cells, particularly in pathological conditions. These proteins share functions as diverse as protection against toxicity mediated by aberrantly folded proteins or oxidative-inflammation conditions. In addition, these proteins share anti-apoptotic properties and are tumorigenic when expressed in cancer cells. This review summarizes the current knowledge about Hsp27 and alphaB-crystallin and the implications, either positive or deleterious, of these proteins in pathologies such as neurodegenerative diseases, myopathies, asthma, cataracts and cancers. Approaches towards therapeutic strategies aimed at modulating the expression and/or the activities of Hsp27 and alphaB-crystallin are presented. 相似文献
997.
Pseudomonas aeruginosa is a gram-negative bacterium, opportunistic pathogen, which causes severe acute or chronic infections, as is the case with cystic fibrosis patients. Chronic infections are frequently accompanied by the development of the bacterial population into a specialized community called biofilm. The pelA-G gene cluster of P. aeruginosa has been shown to be involved in pellicle production and biofilm formation. The pel genes have been proposed to contribute to the formation of the exopolysaccharide-containing pellicle. However, the function and the subcellular localization of the seven different Pel proteins are poorly understood. Based on bioinformatics analysis, we have previously considered that PelF is a putative glycosyltransferase (GT4 family), whereas PelG is a Wzx-like polysaccharide transporter from the PST family. In this study we have further characterized the PelC protein. We have shown that PelC is an outer membrane lipoprotein. The N-terminal signal peptide of the PelC lipoprotein is sufficient to target the protein into the membranes. However, by constructing various PelC hybrid proteins we also proposed that efficient and functional outer membrane insertion of PelC requires not only the signal peptide and the lipid modification, but also requires the C-terminal domain of PelC. Because the gene encoding the outer membrane lipoprotein PelC is part of a putative gene cluster involved in exopolysaccharide biogenesis, we suggest that PelC is a new member of the outer membrane auxiliary (OMA) family of lipoprotein whose Wza, involved in Escherichia coli capsular polysaccharide transport, is an archetype. 相似文献
998.
Barjot C Tournaire M Castagnino C Vigor C Vercauteren J Rossi JF 《Life sciences》2007,81(23-24):1565-1574
This study aims to evaluate and compare the antiproliferative and proapoptotic effects of resveratrol (trans-3,4',5-trihydoxystilbene) with two of its naturally occurring oligomers, epsilon-viniferin (a dimer) and miyabenol C (a trimer). Proliferation assays performed on myeloid and lymphoid cell lines show that the three compounds inhibit cell growth of all cell types tested, with miyabenol C being the most efficient (IC50 ranging from 10.8 to 29.4 muM). Further analysis performed on the multiple myeloma cell line U266 shows that all compounds modify cell cycle distribution probably via actions on different targets. Whereas cells treated with resveratrol accumulate in S phase, cells treated with epsilon-viniferin and miyabenol C accumulate in G2/M and G0/G1, respectively. Miyabenol C is also the most efficient at inducing cell death in U266 cells. All compounds induce apoptosis of U266 cells via mechanisms entirely dependent on caspase activation and associated with mitochondrial membrane potential disruption. Compounds do not act directly on the mitochondrial membrane, but could induce activation of upstream caspases such as caspase 8 and/or caspase 2, depending on the compound. In no case did upstream caspase 8 activation involve Fas/FasL interaction. Taken together, these results show that epsilon-viniferin and, more importantly, miyabenol C represent potent antitumor agents that require further investigation, either alone or in combination with resveratrol. 相似文献
999.
Mingardon F Chanal A Tardif C Bayer EA Fierobe HP 《Applied and environmental microbiology》2007,73(22):7138-7149
In this study, novel cellulosome chimeras exhibiting atypical geometries and binding modes, wherein the targeting and proximity functions were directly incorporated as integral parts of the enzyme components, were designed. Two pivotal cellulosomal enzymes (family 48 and 9 cellulases) were thus appended with an efficient cellulose-binding module (CBM) and an optional cohesin and/or dockerin. Compared to the parental enzymes, the chimeric cellulases exhibited improved activity on crystalline cellulose as opposed to their reduced activity on amorphous cellulose. Nevertheless, the various complexes assembled using these engineered enzymes were somewhat less active on crystalline cellulose than the conventional designer cellulosomes containing the parental enzymes. The diminished activity appeared to reflect the number of protein-protein interactions within a given complex, which presumably impeded the mobility of their catalytic modules. The presence of numerous CBMs in a given complex, however, also reduced their performance. Furthermore, a "covalent cellulosome" that combines in a single polypeptide chain a CBM, together with family 48 and family 9 catalytic modules, also exhibited reduced activity. This study also revealed that the cohesin-dockerin interaction may be reversible under specific conditions. Taken together, the data demonstrate that cellulosome components can be used to generate higher-order functional composites and suggest that enzyme mobility is a critical parameter for cellulosome efficiency. 相似文献
1000.