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排序方式: 共有4797条查询结果,搜索用时 15 毫秒
991.
Francesca Moretti Phil Bergman Stacie Dodgson David Marcellin Isabelle Claerr Jonathan M Goodwin Rowena DeJesus Zhao Kang Christophe Antczak Damien Begue Debora Bonenfant Alexandra Graff Christel Genoud John S Reece‐Hoyes Carsten Russ Zinger Yang Gregory R Hoffman Matthias Mueller Leon O Murphy Ramnik J Xavier Beat Nyfeler 《EMBO reports》2018,19(9)
Autophagy maintains cellular homeostasis by targeting damaged organelles, pathogens, or misfolded protein aggregates for lysosomal degradation. The autophagic process is initiated by the formation of autophagosomes, which can selectively enclose cargo via autophagy cargo receptors. A machinery of well‐characterized autophagy‐related proteins orchestrates the biogenesis of autophagosomes; however, the origin of the required membranes is incompletely understood. Here, we have applied sensitized pooled CRISPR screens and identify the uncharacterized transmembrane protein TMEM41B as a novel regulator of autophagy. In the absence of TMEM41B, autophagosome biogenesis is stalled, LC3 accumulates at WIPI2‐ and DFCP1‐positive isolation membranes, and lysosomal flux of autophagy cargo receptors and intracellular bacteria is impaired. In addition to defective autophagy, TMEM41B knockout cells display significantly enlarged lipid droplets and reduced mobilization and β‐oxidation of fatty acids. Immunostaining and interaction proteomics data suggest that TMEM41B localizes to the endoplasmic reticulum (ER). Taken together, we propose that TMEM41B is a novel ER‐localized regulator of autophagosome biogenesis and lipid mobilization. 相似文献
992.
Abstract The structure of the secondary egg envelope of seven species of Cyprinodontidae belonging to the genus Epiplatys was observed by transmission and scanning electron microscopy. The transverse structure of the secondary envelope examined by transmission electron microscopy is a constant feature in all the species studied and represents a good criterion for identification. In contrast, the surface structure of the secondary envelope when observed by scanning electron microscopy exhibits a great diversity of form. It is possible to distinguish each of the seven different species by the pattern of ornamentation, the width of the polygons and the size of the granules comprising them on the secondary egg envelope. 相似文献
993.
High-affinity maltose/trehalose transport system in the hyperthermophilic archaeon Thermococcus litoralis. 总被引:2,自引:2,他引:0
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K B Xavier L O Martins R Peist M Kossmann W Boos H Santos 《Journal of bacteriology》1996,178(16):4773-4777
The hyperthermophilic marine archaeon Thermococcus litoralis exhibits high-affinity transport activity for maltose and trehalose at 85 degrees C. The K(m) for maltose transport was 22 nM, and that for trehalose was 17 nM. In cells that had been grown on peptone plus yeast extract, the Vmax for maltose uptake ranged from 3.2 to 7.5 nmol/min/mg of protein in different cell cultures. Cells grown in peptone without yeast extract did not show significant maltose or trehalose uptake. We found that the compound in yeast extract responsible for the induction of the maltose and trehalose transport system was trehalose. [14C]maltose uptake at 100 nM was not significantly inhibited by glucose, sucrose, or maltotriose at a 100 microM concentration but was completely inhibited by trehalose and maltose. The inhibitor constant, Ki, of trehalose for inhibiting maltose uptake was 21 nM. In contrast, the ability of maltose to inhibit the uptake of trehalose was not equally strong. With 20 nM [14C]trehalose as the substrate, a 10-fold excess of maltose was necessary to inhibit uptake to 50%. However, full inhibition was observed at 2 microM maltose. The detergent-solubilized membranes of trehalose-induced cells contained a high-affinity binding protein for maltose and trehalose, with an M(r) of 48,000, that exhibited the same substrate specificity as the transport system found in whole cells. We conclude that maltose and trehalose are transported by the same high-affinity membrane-associated system. This represents the first report on sugar transport in any hyperthermophilic archaeon. 相似文献
994.
The influence of different light qualities on the photosynthetic rate, dark respiration, intracellular carbon and nitrogen content, and accumulation of photosynthetic pigments and cell-wall polysaccharides during short-term incubation (5 h) of the red algaGelidium sesquipedale was investigated. The same photon irradiance of 50mol m–2 s–2 below the light saturation point of photosynthesis was applied in each case. Blue light stimulated photosynthesis, dark respiration and the accumulation of chlorophyll and biliproteins, phycoerythrin in particular. The accumulation of internal carbon and nitrogen was greater under blue light than under the other light qualities. In contrast, the percentage of cell-wall polysaccharides was higher in red light. The content of cell-wall polysaccharides decreased during the time of incubation in all light treatments except in red light. The action of a non-photosynthetic photoreceptor in the control of cell-wall polysaccharide synthesis is suggested because the accumulation of cell-wall polysaccharides was not correlated with net photosynthesis in contrast to what occurred with carbon, chlorophyll and phycoerythrin accumulation. 相似文献
995.
Viviane Dumur Elisabeth Trivier Bernard Puech Frédéric Peugnet Xavier Zanlonghi Jean Claude Hache André Hanauer 《Human genetics》1995,96(1):79-82
The gene involved in juvenile retinoschisis (RS) has previously been localized, by genetic linkage analyses, to Xp22.1-p22.2, between DXS274 and DXS43/ DXS207; it is closely linked to the latter markers. From our recent data, this interval represents a genetic distance of approximately 10 cM. In the present study, we have studied 14 French families with X-linked juvenile RS by using four CA polymorphisms that are closely linked to the RS locus and that have recently been included in an Xp22.1-p22.2 high-resolution map. Complete cosegregation with the disease locus was observed for three of them, DXS207, DXS418, and DXS999, which further confirms the locus homogeneity for RS and the close linkage to this region. One recombinant was found with the most proximal marker, AFM291wf5, thereby defining this marker as the new proximal boundary of the candidate region for RS. Under the assumption that DXS207 and DXS43 constitute the distal boundary, the present study further reduces the region containing the disease gene to a interval of 3–4 cM. The results reported here should facilitate the eventual cloning of the RS gene. 相似文献
996.
Fataki Bombil Jean Pierre Kints Xavier Havaux Jean Marie Scheiff Hervé Bazin Dominique Latinne 《Cancer immunology, immunotherapy : CII》1995,40(6):383-389
The transfer of human peripheral blood mononuclear cells (hu-PBMC) from adult Epstein-Barr- virus(EBV)-seropositive donors
in SCID (severe combined immunodeficiency) mice frequently leads to the development of a human B lymphoproliferative syndrome
(hu-BLPS). Therefore, as 90% of adult potential donors are EBV-seropositive, efforts have to be made to avoid the occurrence
of this B lymphoproliferative disorder. McCune et al. [Science 241:1632 (1988)] used human fetal organs for a human SCID graft.
This system does not give rise to hu-BLPS but human fetal organs are much less available than peripheral blood leucocytes.
The experiments reported in this paper show how crucial is the presence of functional T lymphocytes for a graft to take and for development of hu-BLPS in hu-PBMC-reconstituted SCID mice, since inhibition of
T lymphocyte by a rat anti-(human CD2) monoclonal antibody (LO-CD2a) during the first 10 days of the graft prevents successful
engraftment of human normal lymphocytes as well as hu-BLPS in SCID mice. The transfer of B cells alone or B cells plus monocytes
in SCID mice does not permit either long-term engraftment or development of hu-BLPS. We also demonstrate that hu-PBMC treated
with L-leucine methyl ester are less susceptible to the development of hu-BLPS after engraftment in SCID mice than are untreated
hu-PBMC. The mechanism of action of L-leucine methyl ester on these cells is discussed.
Received: 12 December 1994 / Accepted: 20 March 1995 相似文献
997.
An ultrastructural study of the manchette was carried out on 21 species belonging to the culicid genera Aedes, Anopheles, Culex and Toxorhynchites . Each genus has a characteristic morphological type of manchette. Toxorhynchites seems to have the type found in many other Diptera, while the other genera have unusual types. 相似文献
998.
999.
Endurance training affects myosin heavy chain phenotype in regenerating fast-twitch muscle 总被引:2,自引:0,他引:2
Bigard Xavier A.; Janmot Chantal; Merino Daniele; Lienhard Francoise; Guezennec Yannick C.; D'Albis Anne 《Journal of applied physiology》1996,81(6):2658-2665
Bigard, Xavier A., Chantal Janmot, Danièle Merino,Françoise Lienhard, Yannick C. Guezennec, and Anne D'Albis.Endurance training affects myosin heavy chain phenotype inregenerating fast-twitch muscle. J. Appl.Physiol. 81(6): 2658-2665, 1996.The aim of thisstudy was to analyze the effects of treadmill training (2 h/day, 5 days/wk, 30 m/min, 7% grade for 5 wk) on the expression of myosinheavy chain (MHC) isoforms during and after regeneration of afast-twitch white muscle [extensor digitorum longus (EDL)]. Male Wistar rats were randomly assigned to a sedentary(n = 10) or an endurance-trained (ET;n = 10) group. EDL muscle degeneration and regeneration were induced by two subcutaneous injections of a snaketoxin. Five days after induction of muscle injury, animals were trainedover a 5-wk period. It was verified that ~40 days after venomtreatment, central nuclei were present in the treated EDL muscles fromsedentary and ET rats. The changes in the expression of MHCs in EDLmuscles were detected by using a combination of biochemical andimmunocytochemical approaches. Compared with contralateral nondegenerated muscles, relative concentrations of types I, IIa, andIIx MHC isoforms in ET rats were greater in regenerated EDL muscles(146%, P < 0.05; 76%,P < 0.01; 87%,P < 0.01, respectively). Their elevation corresponded to a decreasein the relative concentration of type IIb MHC (36%,P < 0.01). Although type I accountedfor only 3.2% of total myosin in regenerated muscles from the ETgroup, the cytochemical analysis showed that the proportion of positive staining with the slow MHC antibody was markedly greater in regenerated muscles than in contralateral ones. Collectively, these results demonstrate that the regenerated EDL muscle is sensitive to endurance training and suggest that the training-induced shift in MHC isoforms observed in these muscles resulted from an additive effect of regeneration and repeated exercise. 相似文献
1000.
Implication of mitochondria in apoptosis 总被引:17,自引:0,他引:17
Patrice Xavier Petit Naoufal Zamzami Jean-Luc Vayssière Bernard Mignotte Guido Kroemer Maria Castedo 《Molecular and cellular biochemistry》1997,174(1-2):185-188
The induction phase of programmed cell death (PCD) or apoptosis is characterized by an extreme heterogeneity of potential PCD-triggering signal transduction pathways. During the subsequent effector phase, the numerous PCD-inducing stimuli converge into a few stereotypical pathways and cells pass a 'point of no return', thus becoming irreversibly committed to death. Evidence is accumulating that cytoplasmic structures, including mitochondria, participate in the critical effector stage and that alterations usually considered to define apoptosis, as nuclear chromatolysis and cytolysis, have to be ascribed to the late degradation phase. We and others have recently shown that nuclear features of apoptosis are preceded by alterations in mitochondrial function and structure. The importance of these alterations for the apoptotic process and also the possible link between, these observations, the permeability transition pore and the programmed cell death, are dicussed. (Mol Cell Biochem 174: 185–188, 1997) 相似文献