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排序方式: 共有2995条查询结果,搜索用时 15 毫秒
971.
Delphine Judith Mehdi Bourai Nicolas Gangneux Mickaël Lelek Marianne Lucas‐Hourani Nadège Cayet Yves Jacob Marie‐Christine Prévost Philippe Pierre Frédéric Tangy Christophe Zimmer Pierre‐Olivier Vidalain Thérèse Couderc Marc Lecuit 《EMBO reports》2013,14(6):534-544
Chikungunya virus (CHIKV) is a recently re‐emerged arbovirus that triggers autophagy. Here, we show that CHIKV interacts with components of the autophagy machinery during its replication cycle, inducing a cytoprotective effect. The autophagy receptor p62 protects cells from death by binding ubiquitinated capsid and targeting it to autophagolysosomes. By contrast, the human autophagy receptor NDP52—but not its mouse orthologue—interacts with the non‐structural protein nsP2, thereby promoting viral replication. These results highlight the distinct roles of p62 and NDP52 in viral infection, and identify NDP52 as a cellular factor that accounts for CHIKV species specificity. 相似文献
972.
Anne Postec Marianne Quéméneur Aurélien Lecoeuvre Nicolas Chabert Manon Joseph Gaël Erauso 《Systematic and applied microbiology》2021,44(2):126175
Two novel anaerobic alkaliphilic strains, designated as LacTT and LacVT, were isolated from the Prony Bay Hydrothermal Field (PBHF, New Caledonia). Cells were motile, Gram-positive, terminal endospore-forming rods, displaying a straight to curved morphology during the exponential phase. Strains LacTT and LacVT were mesophilic (optimum 30 °C), moderately alkaliphilic (optimum pH 8.2 and 8.7, respectively) and halotolerant (optimum 2% and 2.5% NaCl, respectively). Both strains were able to ferment yeast extract, peptone and casamino acids, but only strain LacTT could use sugars (glucose, maltose and sucrose). Both strains disproportionated crotonate into acetate and butyrate. Phylogenetic analysis revealed that strains LacTT and LacVT shared 96.4% 16S rRNA gene sequence identity and were most closely related to A. peptidifermentans Z-7036, A. namsaraevii X-07-2 and A. hydrothermalis FatMR1 (95.7%–96.3%). Their genome size was of 3.29 Mb for strain LacTT and 3.06 Mb for strain LacVT with a G + C content of 36.0 and 33.9 mol%, respectively. The ANI value between both strains was 73.2 %. Finally, strains LacTT (=DSM 100337 = JCM 30643) and LacVT (=DSM 100017 = JCM 30644) are proposed as two novel species of the genus Alkaliphilus, order Clostridiales, phylum Firmicutes, Alkaliphilus serpentinus sp. nov. and Alkaliphilus pronyensis sp. nov., respectively. The genomes of the three Alkaliphilus species isolated from PBHF were consistently detected in the PBHF chimney metagenomes, although at very low abundance, but not significantly in the metagenomes of other serpentinizing systems (marine or terrestrial) worldwide, suggesting they represent indigenous members of the PBHF microbial ecosystem. 相似文献
973.
Gousy-Leblanc Marianne Yannic Glenn Therrien Jean-François Lecomte Nicolas 《Conservation Genetics》2021,22(5):685-702
Conservation Genetics - The current and rapid anthropogenic environmental changes could disproportionately impact ecosystems, particularly when they affect species with critical roles in ecosystem... 相似文献
974.
Jennyfer Levoux Alexandre Prola Peggy Lafuste Marianne Gervais Nathalie Chevallier Zeynab Koumaiha Kaouthar Kefi Laura Braud Alain Schmitt Azzedine Yacia Aurélie Schirmann Barbara Hersant Mounia Sid-Ahmed Sabrina Ben Larbi Katerina Komrskova Jakub Rohlena Frederic Relaix Jiri Neuzil Anne-Marie Rodriguez 《Cell metabolism》2021,33(3):688-690
975.
Guillaume Pierre Valérie Sopena Camille Juin Amira Mastouri Marianne Graber Thierry Maugard 《Biotechnology and Bioprocess Engineering》2011,16(5):937-945
The in vitro antimicrobial activity of the marine green algae Chaetomorpha aerea was investigated against gram-positive bacteria, gram-negative bacteria, and a fungus. The water-soluble extract of algae
was composed of a sulfated (6.3%) galactan with a molecular weight of 1.160 × 106 Da and a global composition close to commercial polysaccharides, such as dextran sulfate or fucoidan. The polysaccharide
was composed of 18% arabinose, 24% glucose, and 58% galactose. The re-suspended extracts (methanol, water) exhibited selective
antibacterial activities against 3 gram-positive bacteria including Staphylococcus aureus (ATCC 25923). Minimum inhibitory concentration and minimum bactericidal concentration tests showed that the sulfated galactan
could be a bactericidal agent for this strain (40 mg/mL). The results of this study confirmed the potential use of the green
algae Chaetomorpha aerea as a source of antibacterial compounds. 相似文献
976.
977.
van Hees H Ottenheijm C Ennen L Linkels M Dekhuijzen R Heunks L 《American journal of physiology. Lung cellular and molecular physiology》2011,301(1):L110-L116
Diaphragm muscle weakness in patients with chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and mortality. Recent studies indicate that increased contractile protein degradation by the proteasome contributes to diaphragm weakness in patients with COPD. The aim of the present study was to investigate the effect of proteasome inhibition on diaphragm function and contractile protein concentration in an animal model for COPD. Elastase-induced emphysema in hamsters was used as an animal model for COPD; normal hamsters served as controls. Animals were either treated with the proteasome inhibitor Bortezomib (iv) or its vehicle saline. Nine months after induction of emphysema, specific force-generating capacity of diaphragm bundles was measured. Proteolytic activity of the proteasome was assayed spectrofluorometrically. Protein concentrations of proteasome, myosin, and actin were measured by means of Western blotting. Proteasome activity and concentration were significantly higher in the diaphragm of emphysematous hamsters than in normal hamsters. Bortezomib treatment reduced proteasome activity in the diaphragm of emphysematous and normal hamsters. Specific force-generating capacity and myosin concentration of the diaphragm were reduced by ~25% in emphysematous hamsters compared with normal hamsters. Bortezomib treatment of emphysematous hamsters significantly increased diaphragm-specific force-generating capacity and completely restored myosin concentration. Actin concentration was not affected by emphysema, nor by bortezomib treatment. We conclude that treatment with a proteasome inhibitor improves contractile function of the diaphragm in emphysematous hamsters through restoration of myosin concentration. These findings implicate that the proteasome is a potential target of pharmacological intervention on diaphragm weakness in COPD. 相似文献
978.
Marianne Evju Rune Halvorsen Knut Rydgren Gunnar Austrheim Atle Mysterud 《Plant Ecology》2011,212(8):1299-1312
An improved understanding of population-level consequences of grazing on plants can be facilitated by an assessment of grazing
effects on all stages in the life-cycle. In this study, 6 years of demographic data for three populations of the perennial
herb Geranium sylvaticum were analysed. We examined the effects of sheep grazing (high sheep density, low sheep density and no sheep) and interannual
climatic variability on vital rates and population growth rates (λ). Grazing did not affect survival or flowering rates, but
reduced rates of growth and increased rates of clonal reproduction. At the population level, high contributions from retrogression
and clonal reproduction buffered reduced rates of growth and stasis, and no consistent differences in λ between populations
exposed to different sheep densities were found. Instead, large between-year variability in λ, independent of sheep density,
was detected, related to variation in the local summer climate. The results indicated, however, that grazing effects on λ
were more severe in unfavourable than in normal years. Our study highlights that increased clonal reproduction rates functioned
as a tolerance mechanism towards grazing in this herb, which forms a mechanism to explain how moderate population responses
to grazing in some herbs can arise. 相似文献
979.
WNT/Frizzled receptor (FZD) signaling pathways are pivotal for physiological and pathophysiological processes. In humans, the complexity of WNT/FZD signaling is based on 19 WNTs, 10 FZDs and at least two (co)receptors (LRP5/6) mediating supposably four different signaling cascades. The detailed investigation of the specific function of the different initiating components is primarily hampered by the lack of most WNT proteins in a purified form. Therefore, we constructed and examined a chimeric protein of WNT3a and FZD4 as a suitable approach to overcome this obstacle for future studies of the specificity of other WNT/FZD combinations. Furthermore, we produced four different reporter HEK 293 cell lines to quantify the induced activation of the proposed signaling cascades, the β-catenin-, the NFAT-, the AP-1- and the CRE-regulated pathways. The chimera WNT3aFZD4 efficiently induced β-catenin-mediated luciferase activity. This activity was increased 40-fold compared with basal when LRP6 was stably cotransfected, proving that the chimera WNT3aFZD4 can also interact efficiently with LRP6. Our results demonstrate that the approach of using reporter gene cell lines in combination with WNT/FZD chimeras is efficient to study the β-catenin-mediated pathway and should also allow clarifying the specificity of WNT/FZD combinations in the activation of the other pathways. 相似文献
980.
Suzanne Zuyderduyn Dennis K Ninaber Jasmijn A Schrumpf Marianne AJA van Sterkenburg Renate M Verhoosel Frans A Prins Sandra van Wetering Klaus F Rabe Pieter S Hiemstra 《Respiratory research》2011,12(1):59
The airway epithelium forms a barrier against infection but also produces antimicrobial peptides (AMPs) and other inflammatory mediators to activate the immune system. It has been shown that in allergic disorders, Th2 cytokines may hamper the antimicrobial activity of the epithelium. However, the presence of Th2 cytokines also affects the composition of the epithelial layer which may alter its function. Therefore, we investigated whether exposure of human primary bronchial epithelial cells (PBEC) to Th2 cytokines during mucociliary differentiation affects expression of the human cathelicidin antimicrobial protein (hCAP18)/LL-37 and human beta defensins (hBD), and antimicrobial activity.PBEC were cultured at an air-liquid interface (ALI) for two weeks in the presence of various concentrations of IL-4 or IL-13. Changes in differentiation and in expression of various AMPs and the antimicrobial proteinase inhibitors secretory leukocyte protease inhibitor (SLPI) and elafin were investigated as well as antimicrobial activity.IL-4 and IL-13 increased mRNA expression of hCAP18/LL-37 and hBD-2. Dot blot analysis also showed an increase in hCAP18/LL-37 protein in apical washes of IL-4-treated ALI cultures, whereas Western Blot analysis showed expression of a protein of approximately 4.5 kDa in basal medium of IL-4-treated cultures. Using sandwich ELISA we found that also hBD-2 in apical washes was increased by both IL-4 and IL-13. SLPI and elafin levels were not affected by IL-4 or IL-13 at the mRNA or protein level. Apical wash obtained from IL-4- and IL-13-treated cultures displayed increased antimicrobial activity against Pseudomonas aeruginosa compared to medium-treated cultures. In addition, differentiation in the presence of Th2 cytokines resulted in increased MUC5AC production as has been shown previously.These data suggest that prolonged exposure to Th2 cytokines during mucociliary differentiation contributes to antimicrobial defence by increasing the expression and release of selected antimicrobial peptides and mucus. 相似文献