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101.
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103.
哈尔滨西郊赤狐冬季巢区的初步研究 总被引:5,自引:2,他引:3
本文利用雪地跟踪方法对哈尔滨西郊5只赤狐在1985-1986年冬季的巢区做了观察。结果表明,5只狐对巢区内各部分使用的强度是不等的,对巢区中部的某些地块使用强度要高于对外围的使用,并具有明显的方向性。5个巢区的平均活动半径为320±68米至557±82米,面积为1.44-4.O9平方公里,线性指数为1.079至2。5只狐相邻距离约1000米。 相似文献
104.
Nonglucosylated oligosaccharides are transferred to protein in MI8-5 Chinese hamster ovary cells 总被引:3,自引:2,他引:1
A CHO mutant MI8-5 was found to synthesize Man9-GlcNAc2-P-P-dolichol rather
than Glc3Man9GlcNAc2-P-P-dolichol as the oligosaccharide-lipid intermediate
in N-glycosylation of proteins. MI8-5 cells were incubated with labeled
mevalonate, and the prenol was found to be dolichol. The mannose-labeled
oligosaccharide released from oligosaccharide-lipid of MI8-5 cells was
analyzed by HPLC and alpha-mannosidase treatment, and the data were
consistent with a structure of Man9GlcNAc2. In addition, MI8-5 cells did
not incorporate radioactivity into oligosaccharide- lipid during an
incubation with tritiated galactose, again consistent with MI8-5 cells
synthesizing an unglucosylated oligosaccharide-lipid. MI8-5 cells had
parental levels of glucosylphosphoryldolichol synthase activity. However,
in two different assays, MI8-5 cells lacked dolichol-
P-Glc:Man9GlcNAc2-P-P-dolichol glucosyltransferase activity. MI8-5 cells
were found to synthesize glucosylated oligosaccharide after they were
transfected with Saccharomyces cerevisiae ALG 6, the gene for
dolichol-P-Glc:Man9GlcNAc2-P-P-dolichol glucosyltransferase. MI8-5 cells
were found to incorporate mannose into protein 2-fold slower than parental
cells and to approximately a 2-fold lesser extent.
相似文献
105.
Beaulieu PL Bös M Bousquet Y Fazal G Gauthier J Gillard J Goulet S LaPlante S Poupart MA Lefebvre S McKercher G Pellerin C Austel V Kukolj G 《Bioorganic & medicinal chemistry letters》2004,14(1):119-124
Benzimidazole 5-carboxamide derivatives from a combinatorial screening library were discovered as specific inhibitors of the NS5B polymerase of the hepatitis C virus (HCV). Initial hit-to-lead activities taking advantage of high-throughput parallel synthetic techniques, identified a 1,2-disubstituted benzimidazole 5-carboxylic acid scaffold as the minimum core for biological activity. Potent analogues in this series inhibit the polymerase at low micromolar concentrations and provide an attractive "drug-like" lead structure for further optimization and the development of potential HCV therapeutics. 相似文献
106.
Cui J Smith RG Mount GR Lo JL Yu J Walsh TF Singh SB DeVita RJ Goulet MT Schaeffer JM Cheng K 《Molecular endocrinology (Baltimore, Md.)》2000,14(5):671-681
The dog GnRH receptor was cloned to facilitate the identification and characterization of selective nonpeptide GnRH antagonists. The dog receptor is 92% identical to the human GnRH receptor. Despite such high conservation, the quinolone-based nonpeptide GnRH antagonists were clearly differentiated by each receptor species. By contrast, peptide antagonist binding and functional activity were not differentiated by the two receptors. The basis of the differences was investigated by preparing chimeric receptors followed by site-directed mutagenesis. Remarkably, a single substitution of Phe313 to Leu313 in the dog receptor explained the major differences in binding affinities and functional activities. The single amino acid replacement of Phe313 of the human receptor with Leu313 resulted in a 160-fold decrease of binding affinity of the nonpeptide antagonist compound 1. Conversely, the replacement of Leu313 of the dog receptor with Phe313 resulted in a 360-fold increase of affinity for this compound. These results show that Phe313 of the GnRH receptor is critical for the binding of this structural class of GnRH antagonists and that the dog receptor can be "humanized" by substituting Leu for Phe. This study provides the first identification of a critical residue in the binding pocket occupied by nonpeptide GnRH antagonists and reinforces cautious extrapolation of ligand activity across highly conserved receptors. 相似文献
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Katelyn Hamilton Celine T. Goulet Emily M. Drummond Anna F. Senior Mellesa Schroder Michael G. Gardner Geoffrey M. While David G. Chapple 《Austral ecology》2021,46(1):8-19
The rapid changes in altitude, and associated habitat, of mountain ecosystems make them ideal natural laboratories for testing the effect of environmental heterogeneity on species assemblage. Our understanding of the sensitivity of Australian reptiles to elevational clines is limited. We examined lizard distribution across three elevation zones (montane, subalpine and alpine), spanning from 900 to 1840 m above sea level, in the Australian alps. We aimed to examine how elevation influences species diversity and abundance, and ectoparasite load, and whether species alter their habitat use amongst different elevational zones. Active searches were conducted across the elevation zones to identify lizard community structure (at least 16 species) across elevational zones, along with skink habitat preferences and the ectoparasite load. Skink diversity and abundance were negatively correlated with increased elevation. The alpine zone had significantly lower diversity and abundance of skinks. Habitat use differed amongst both elevations and species. Ectoparasite prevalence was also significantly diminished in the alpine zone. Ectoparasites only infected a subset of the skink community, with ectoparasite load increasing as the active season progressed. This study provides evidence of the complex interplay between elevation and species diversity, as well as the differences in ectoparasite pressure along elevational gradients in the Australian alps. 相似文献
110.
Duijnisveld BJ Bigot A Beenakker KG Portilho DM Raz V van der Heide HJ Visser CP Chaouch S Mamchaoui K Westendorp RG Mouly V Butler-Browne GS Nelissen RG Maier AB 《Arthritis research & therapy》2011,13(6):R207-10