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排序方式: 共有141条查询结果,搜索用时 10 毫秒
1.
Characterization of Gypsy Moth (Lymantria dispar) Nuclear Polyhedrosis Virus 总被引:1,自引:0,他引:1 下载免费PDF全文
Characterization of the proteins and nucleic acid of the gypsy moth nuclear polyhedrosis virus isolated in Ithaca, N.Y. (LdNPV-IT) is presented. A total of 29 viral structural proteins were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis when the virus was isolated in the absence of alkaline protease activity. Fourteen surface envelope viral proteins were identified by lactoperoxidase iodination. Eleven proteins were associated with nucleocapsids prepared by Nonidet P-40 detergent treatment. Distinct alterations of viral proteins were documented when virions were purified in the presence of occlusion body-associated alkaline protease(s). Restriction enzyme digests of viral DNA indicated that this isolate was composed of a large number of genetic variants. On the basis of the major molar fragments resulting from EcoRI, BamHI, BglII, and HindIII digests, the molecular weight of the LdNPV genome was approximately 88 × 106. 相似文献
2.
Short and reversible uncoupling evokes little change in the gap junctions of pancreatic acinar cells 总被引:3,自引:0,他引:3
Three different preparations of mouse pancreatic fragments where all the cells tested electrophysiologically showed (a) complete electrical coupling (control), (b) complete uncoupling (after 1-to 2-min exposure to 100% CO2), or (c) complete recoupling (1-2 min after removal of 100% CO2) were fixed, with the electrodes in situ, with 0.2% glutaraldehyde and freeze-fractured for quantitative analysis of acinar cell gap junctions. No obvious difference was observed between gap junctions of coupled and uncoupled acinar cells. However, quantitation revealed a small (2.3-5.6%) increase in particle diameter and spacing within junctions of uncoupled cells. Such increase was rapidly reversed upon cell recoupling. In all preparations, most of the gap junctions were made up of disordered arrays of particles but a few of them showed a more tight packing of their particles of which most had lost the usual globular appearance. These "amorphous" gap junctions had larger particle diameter but smaller particle spacing than the other gap junctions and these parameters were not modified during cell uncoupling. However, "amorphous" gap junctions were more frequent in the latter condition. 相似文献
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F Allagnat P Klee A K Cardozo P Meda J-A Haefliger 《Cell death and differentiation》2013,20(12):1742-1752
Cell-to-cell communication mediated by gap junctions made of Connexin36 (Cx36) contributes to pancreatic β-cell function. We have recently demonstrated that Cx36 also supports β-cell survival by a still unclear mechanism. Using specific Cx36 siRNAs or adenoviral vectors, we now show that Cx36 downregulation promotes apoptosis in INS-1E cells exposed to the pro-inflammatory cytokines (IL-1β, TNF-α and IFN-γ) involved at the onset of type 1 diabetes, whereas Cx36 overexpression protects against this effect. Cx36 overexpression also protects INS-1E cells against endoplasmic reticulum (ER) stress-mediated apoptosis, and alleviates the cytokine-induced production of reactive oxygen species, the depletion of the ER Ca2+ stores, the CHOP overexpression and the degradation of the anti-apoptotic protein Bcl-2 and Mcl-1. We further show that cytokines activate the AMP-dependent protein kinase (AMPK) in a NO-dependent and ER-stress-dependent manner and that AMPK inhibits Cx36 expression. Altogether, the data suggest that Cx36 is involved in Ca2+ homeostasis within the ER and that Cx36 expression is downregulated following ER stress and subsequent AMPK activation. As a result, cytokine-induced Cx36 downregulation elicits a positive feedback loop that amplifies ER stress and AMPK activation, leading to further Cx36 downregulation. The data reveal that Cx36 plays a central role in the oxidative stress and ER stress induced by cytokines and the subsequent regulation of AMPK activity, which in turn controls Cx36 expression and mitochondria-dependent apoptosis of insulin-producing cells. 相似文献
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Dipankar Ray Shirish Shukla Uday Sankar Allam Abigail Helman Susmita Gurjar Ramanand Linda Tran Michael Bassetti Pranathi Meda Krishnamurthy Matthew Rumschlag Michelle Paulsen Lei Sun Thomas P. Shanley Mats Ljungman Mukesh K. Nyati Ming Zhang Theodore S. Lawrence 《PloS one》2013,8(2)
The efficacy of radiation therapy for lung cancer is limited by radiation-induced lung toxicity (RILT). Although tumor necrosis factor-alpha (TNF-α) signaling plays a critical role in RILT, the molecular regulators of radiation-induced TNF-α production remain unknown. We investigated the role of a major TNF-α regulator, Tristetraprolin (TTP), in radiation-induced TNF-α production by macrophages. For in vitro studies we irradiated (4 Gy) either a mouse lung macrophage cell line, MH-S or macrophages isolated from TTP knockout mice, and studied the effects of radiation on TTP and TNF-α levels. To study the in vivo relevance, mouse lungs were irradiated with a single dose (15 Gy) and assessed at varying times for TTP alterations. Irradiation of MH-S cells caused TTP to undergo an inhibitory phosphorylation at Ser-178 and proteasome-mediated degradation, which resulted in increased TNF-α mRNA stabilization and secretion. Similarly, MH-S cells treated with TTP siRNA or macrophages isolated from ttp (−/−) mice had higher basal levels of TNF-α, which was increased minimally after irradiation. Conversely, cells overexpressing TTP mutants defective in undergoing phosphorylation released significantly lower levels of TNF-α. Inhibition of p38, a known kinase for TTP, by either siRNA or a small molecule inhibitor abrogated radiation-induced TNF-α release by MH-S cells. Lung irradiation induced TTPSer178 phosphorylation and protein degradation and a simultaneous increase in TNF-α production in C57BL/6 mice starting 24 h post-radiation. In conclusion, irradiation of lung macrophages causes TTP inactivation via p38-mediated phosphorylation and proteasome-mediated degradation, leading to TNF-α production. These findings suggest that agents capable of blocking TTP phosphorylation or stabilizing TTP after irradiation could decrease RILT. 相似文献
8.
Hammadoum A. Sango Jean Testa Nicolas Meda Benjamin Contrand Mamadou S. Traoré Pascal Staccini Emmanuel Lagarde 《PloS one》2016,11(2)
Background
Low- and middle-income countries are currently facing the massive public health challenge of road traffic injuries. The lack of effective surveillance systems hinders proper assessment of epidemiologic status and intervention priorities. The objective of our study was to estimate the mortality and morbidity attributable to road crashes in Bamako, Mali using the capture-recapture method.Methods
During the 1 January, 2012–31 April, 2012 period, we collected data on road traffic crashes from the road accident registers of the police forces of Bamako, Mali on the one hand, and from a register kept by health facilities in the same area. An automatic, then manual matching procedure was performed to find pairs of records related to the same crash victims. The number of victims and the number of fatalities were estimated by the capture-recapture method using the Chapman estimator.Results
The health facility and the police registries included 3587 and 1432 records, respectively. The matching procedure identified 603 common records, 31 of which were fatalities. The annual incidence estimate for road victims was 1038 in 100 000 and the annual incidence estimate for road fatalities was 12 in 100 000. Victims from both sources were more likely to be male, in the 15–34 age group, and almost half of all injured road users and two in three fatalities were using motorized two-wheelers. One victim out of five was a pedestrian.Conclusion
Our estimates are in line with available literature data from low-income countries. While more cases were reported by health facilities than by police forces, we believe that an effective surveillance system should not be based solely on medical reports as much would be missing as regards the crash circumstances and characteristics. 相似文献9.
Estrada A Luecke L Van Belle S Barrueta E Meda MR 《Primates; journal of primatology》2004,45(1):33-39
Surveys of populations of spider and howler monkeys were conducted at the Mayan sites of Calakmul and Yaxchilán, Mexico and Tikal, Guatemala. The forests in which these sites are found are part of the largest landmass of tropical rain forests present in Mesoamerica, encompassing about 4 million ha. Triangulation of monkey vocalization combined with ground surveys was used to determine the presence of howler and spider monkey groups. Howler monkey mean troop size at these sites varied from 6.6±2.1 individuals in Yaxchilán to 7.5±1.9 in Calakmul to 8.7±2.2 in Tikal. Density estimates varied from 12.8 individuals/km2 in Yaxchilán to 15.2 individuals/km2 in Calakmul to 17.8 individuals/km2 in Tikal. Mean spider monkey subgroup size varied from 4.7±2.6 individuals in Tikal to 5.6±3.0 individuals in Yaxchilán to 7.7±3.8 individuals in Calakmul. Spider monkey density varied from 17.0 individuals/km2 in Yaxchilán to 17.2 individuals/km2 in Calakmul to 56.4 individuals/km2 in Tikal. All sightings of both howler and spider monkeys at the three sites were in undisturbed rain forest vegetation and spider monkeys in general were more frequently sighted at higher tree heights than howlers. We discuss the value of further acquiring data on howler and spider monkey populations existing in extensive forest tracts and on the conservation value for both primate species of the forests surrounding the Mayan ruins found in this area of Mesoamerica. 相似文献
10.
Connexins 43 and 26 are differentially increased after rat bladder outlet obstruction 总被引:12,自引:0,他引:12
Haefliger JA Tissières P Tawadros T Formenton A Bény JL Nicod P Frey P Meda P 《Experimental cell research》2002,274(2):216-225