排序方式: 共有30条查询结果,搜索用时 15 毫秒
1.
2.
Processing of viral envelope glycoprotein by the endomannosidase pathway: evaluation of host cell specificity 总被引:4,自引:2,他引:2
Endo-alpha-D-mannosidase is an enzyme involved in N-linked oligosaccharide
processing which through its capacity to cleave the internal linkage
between the glucose-substituted mannose and the remainder of the
polymannose carbohydrate unit can provide an alternate pathway for
achieving deglucosylation and thereby make possible the continued formation
of complex oligosaccharides during a glucosidase blockade. In view of the
important role which has been attributed to glucose on nascent
glycoproteins as a regulator of a number of biological events, we chose to
further define the in vivo action of endomannosidase by focusing on the
well characterized VSV envelope glycoprotein (G protein) which can be
formed by the large array of cell lines susceptible to infection by this
pathogen. Through an assessment of the extent to which the G protein was
converted to an endo-beta-N- acetylglucosaminidase (endo H)-resistant form
during a castanospermine imposed glucosidase blockade, we found that
utilization of the endomannosidase-mediated deglucosylation route was
clearly host cell specific, ranging from greater than 90% in HepG2 and PtK1
cells to complete absence in CHO, MDCK, and MDBK cells, with intermediate
values in BHK, BW5147.3, LLC-PK1, BRL, and NRK cell lines. In some of the
latter group the electrophoretic pattern after endo H treatment suggested
that only one of the two N-linked oligosaccharides of the G protein was
processed by endomannosidase. In the presence of the specific
endomannosidase inhibitor, Glcalpha1-->3(1- deoxy)mannojirimycin, the
conversion of the G protein into an endo H- resistant form was completely
arrested. While the lack of G protein processing by CHO cells was
consistent with the absence of in vitro measured endomannosidase activity
in this cell line, the failure of MDBK and MDCK cells to convert the G
protein into an endo H-resistant form was surprising since these cell lines
have substantial levels of the enzyme. Similarly, we observed that
influenza virus hemagglutinin was not processed in castanospermine-treated
MDCK cells. Our findings suggest that studies which rely on glucosidase
inhibition to explore the function of glucose in controlling such critical
biological phenomena as intracellular movement or quality control should be
carried out in cell lines in which the glycoprotein under study is not a
substrate for endomannosidase action.
相似文献
3.
Background
Although cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the severity of disease is highly variable indicating the influence of modifier genes. The intestines of Cftr deficient mice (CF mice: Cftr tm1Unc ) are prone to obstruction by excessive mucus accumulation and are used as a model of meconium ileus and distal intestinal obstruction syndrome. This phenotype is strongly dependent on the genetic background of the mice. On the C57Bl/6 background, the majority of CF mice cannot survive on solid mouse chow, have inflammation of the small intestine, and are about 30% smaller than wild type littermates. In this work potential modifier loci of the CF intestinal phenotype were identified.Results
CF mice on a mixed genetic background (95% C57Bl/6 and 5% 129Sv) were compared to CF mice congenic on the C57Bl/6 background for several parameters of the intestinal CF phenotype. CF mice on the mixed background exhibit significantly greater survival when fed dry mouse chow, have reduced intestinal inflammation as measured by quantitative RT-PCR for marker genes, have near normal body weight gain, and have reduced mucus accumulation in the intestinal crypts. There was an indication of a gender effect for body weight gain: males did not show a significant improvement at 4 weeks of age, but were of normal weight at 8 weeks, while females showed improvement at both 4 and 8 weeks. By a preliminary genome-wide PCR allele scanning, three regions were found to be potentially associated with the milder phenotype. One on chr.1, defined by marker D1Mit36, one on chr. 9 defined by marker D9Mit90, and one on chr. 10, defined by marker D10Mit14.Conclusion
Potential modifier regions were found that have a positive impact on the inflammatory phenotype of the CF mouse small intestine and animal survival. Identification of polymorphisms in specific genes in these regions should provide important new information about genetic modifiers of the CF intestinal phenotype. 相似文献4.
Phylogeny of the M superhaplogroup inferred from complete mitochondrial genome sequence of Indian specific lineages 下载免费PDF全文
Revathi Rajkumar Jheelam Banerjee Hima Bindu Gunturi R Trivedi VK Kashyap 《Genome biology》2004,6(2):P3
Background
Phylogenetic analysis of human complete mitochondrial DNA sequences has largely contributed to resolving phylogenies and antiquity of different lineages belonging to the majorhaplogroups L, N and M (East-Asian lineages). In the absence of whole mtDNA sequence information of M lineages reported in India that exhibits highest diversity within the sub-continent, the present study was undertaken to provide a detailed analysis of this haplogroup to precisely characterize the lineages and unravel their intricate phylogeny. 相似文献5.
A Puri R Sethi B Singh SK Dwivedi VS Narain RK Saran VK Puri 《Indian pacing and electrophysiology journal》2009,9(3):186-189
A 25-year-old previously asymptomatic pregnant woman at 36 weeks'' gestation was noticed to have repetitive monomorphic ventricular tachycardia. A dilated left ventricle with moderately reduced systolic function was found on echocardiographic examination. This is a very rare presentation of peripartum cardiomyopathy (PPCMP) presenting with repetitive monomorphic ventricular tachycardia. 相似文献
6.
A Rajor R Sharma VK Sood Dr V Ramamurthy 《Journal of industrial microbiology & biotechnology》1996,16(4):237-240
Sawdust, a bulky waste generated by wood processing industries, has very few profitable and ecofriendly uses and poses a problem of proper disposal. Treatment with the fungusVolvariella volvaceae and a dilute solution of urea converted sawdust from a phytoinhibitory material to a phytostimulatory soil conditioner. In different types of soils, the soil conditioner increased the moisture retention and facilitated the cohesive interaction of particles. Analyses of the major biopolymers of sawdust after fungal treatment indicated that levels of cellulose, hemicellulose and lignin decreased; however, these changes did not account for the plant growth stimulatory property attained by this material. 相似文献
7.
N E Kushlinski? V G Degtiar' T V Babkina Iu N Solov'ev M D Aliev N N Trapeznikov 《Uspekhi fiziologicheskikh nauk》1999,30(3):14-22
The paper provides data of comparative assessment of activity of the key enzymes in metabolism of androgens in various morphological variants of sarcomas and benign bone tumors in 46 patients within the age range from 15 to 61, which were under treatment in the ORC named after N. N. Blokhin, RAMS, from 1996 to 1997. On the basis on publications and our own research results we can suggest that malignant human bone tumors of various histogenesis are subject to metabolic processes of testosterone (T), the principal androgen regulator in the bone tissue, as well as formation in bones of 5 alpha-dihydrotestosterone (DHT). One cannot exclude a possibility that metabolism of androgen in bone tissues is directed towards formation of other androgens (in addition to DHT), which may participate in the bone tissue regulation, for instance, 3 alpha- and 3 beta-diols; specific activity of the latter has recently been intensively scrutinized. One can expect that further research shall disclose the clinical significance of metabolism of androgens and of individual androgens in human bone formations. 相似文献
8.
Trapeznikov AV Korzhavin AV Nikolkin VN Trapeznikova VN Migunov VI 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2006,46(5):590-595
The radioecological research of Irtysh-river and Ob-river was held. The content of 137Cs in Irtysh water was compounded 0.62-1.23 Bq/m3, in Ob-- 0.24-0.27 Bq/m3, and the one of 90Sr in Irtysh-- 10-20 Bq/m3, and in Ob-- 5-10 Bq/m3, that is much lower than the permissible sanitary-hygienic norms for the population. The 137Cs stores density on Irtysh-river input lease was compounded 2.7 kBq/m2, is almost in 11 times slashed downstream and is peer 245 kBq/m2 before the Irtysh-river lockin. The 90Sr stores density also was slashed in surveyed leases with 212 down to 106 Bq/m2. Two variants of integrated stores of 137Cs and of 90Sr in flood of the Irtysh-river was held. The balance calculation of annual radionuclides sinks confirms the dominant amount of 137Cs and of 90Sr in downstream Ob-river leases acts now on the Ob's sleeve, instead of from the Irtysh-river as it was supposed earlier. The 137Cs medial annual inflow from the Ob's sleeve almost is in 2 times, and the 90Sr inflow is in 2.3 times more, than are acts from Irtysh-river sleeve. 相似文献
9.
10.