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31.
Ahmed Chadli Jean-Pierre LeCaer Dominique Bladier Raymonde Joubert-Caron Michel Caron 《Journal of neurochemistry》1997,68(4):1640-1647
Abstract: Our previous studies have characterized an endogenous lectin from human brain identified as galectin-1. A soluble ligand of galectin-1 was purified from human brain by affinity chromatography and preparative electrophoresis. The purified ligand (termed HBGp82, for human brain galectin-1-binding polypeptide of 82,000 daltons) has an apparent molecular mass of 82 kDa and is glycosylated by N -linked biantennary complex structures. HBGp82 was partially characterized by microsequencing of peptide fragments. Similar peptides were found in a heat shock of protein of 90,000 daltons, hsp90. However, comparison of apparent molecular weights and matrix-assisted laser desorption mass spectrometry clearly showed that HBGp82 differs to some degree from hsp90. 相似文献
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Wolfgang Schepp Siegfried Ernst Miederer Hans-Jörg Ruoff 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1984,804(2):192-199
Human gastric mucosal cells were isolated from the resected fundic mucosa of peptic ulcer patients. The intracellular content and secretion of intrinsic factor were estimated by binding to cyano[57Co]cobalamin. The content was maximal in the enriched parietal cell fraction which also displayed the highest H+ production as measured by amino[14C]pyrine uptake. Secretagogues evoked full response after 15 min of incubation: pentagastrin (181% of basal secretion), carbachol (208%), histamine (250%) and dibutyryl cyclic adenosine monophosphate (304%). The phosphodiesterase inhibitor isobutylmethylxanthine was slightly more effective even than dibutyryl cAMP. The response to histamine was abolished by ranitidine, indicating activation of adenylate cyclase via histamine H2 receptors, but remained unaffected by atropine, which in turn blocked the carbachol effect, whereas ranitidine was ineffective. The mean formation rate was 8.4 fmol intrinsic factor/106 cells per h under basal conditions and 14.3 fmol in response to histamine. 相似文献
35.
PHI--a new brain-gut peptide 总被引:3,自引:0,他引:3
K Tatemoto 《Peptides》1984,5(2):151-154
The detection of the C-terminal amide structure in porcine intestinal extracts has led to the discovery of a 27 amino acid residue peptide designated PHI (PHI-27, peptide HI). The peptide was found to have structural homologies to vasoactive intestinal peptide (VIP) and growth hormone-releasing factor (GRF). Subsequent studies have revealed that PHI exhibits a variety of biological activities which resemble those of VIP. Moreover, it was found that the peptide is able to inhibit the binding of VIP to its receptors, and to stimulate cyclic AMP production. PHI is present in both brain and gut in high concentrations and probably acts as a neurotransmitter or neuromodulator rather than a hormone. A comparison of the amino acid sequences of porcine, human and bovine PHI indicated that human PHI differs from the porcine peptide in two positions (12 and 27), and bovine PHI differs in one position (10). The amino acid sequence (deduced from the cDNA sequence) of the VIP precursor recently obtained from human neuroblastoma cells also contains an identical sequence to the newly-isolated human PHI from human colonic extracts. PHI has thus been shown to be co-synthesized with VIP in the same precursor molecule. 相似文献
36.
Molecular genetic and phenotypic alteration of Escherichia coli in natural water microcosms containing toxic chemicals 总被引:2,自引:0,他引:2
Abstract Microcosms of sterile Chesapeake Bay water were used to study effects of sub-lethal concentrations (1 μl/l) of nitrobenzene, m -cresol, and dibutyl phthalate on Escherichia coli H10407. E. coli remained viable during the 19-day test period in estuarine water, both in the presence and absence of the chemicals, long after it became non-culturable. Analysis of membrane proteins revealed changes in the protein composition. Carbohydrate and amino acid utilization was affected by these changes. Plasmids in E. coli H10407 could not be detected following microcosm exposure. When the cells were transferred to rich medium without toxic chemicals, growth resumed and plasmid bands were again detectable. 相似文献
37.
H. Meijer C.A. Bruggeman P.H.J. Dormans C.P.A. van Boven 《FEMS microbiology letters》1984,25(2-3):283-287
Abstract A cytosol deoxyguanosine kinase (dGK) is induced in either growing or human cytomegalovirus (HCMV, AD169)-infected human fibroblasts (HEF). Data obtained from polyacrylamide gel electrophoresis, heat inactivation and phosphorylation kinetic experiments proved that these dGKs are identical, but completely differ from HCMV-induced thymidine kinase (TK) or deoxycytidine kinase (dCK). In contrast to TK or dCK, only dGK interacts with Acyclovir ( K i = 590 μ M). It is suggested that dGK is an important enzyme determining the antiviral activity of Acyclovir. 相似文献
38.
M. E. Wolf P. A. LeWitt M. J. Bannon L. J. Dragovic G. Kapatos 《Journal of neurochemistry》1991,56(4):1191-1200
This study examined the effect of aging on the relative number of dopamine (DA) nerve terminals in human caudate nucleus, their content of tyrosine hydroxylase (TH) protein, and the relative abundance of TH monomers with different molecular weights. Preliminary studies on brain tissue cryopreservation, performed with rat striatum, indicated that intact synaptosomes can be prepared from fresh tissue slowly frozen in 0.32 M sucrose with 5% dimethyl sulfoxide and then thawed rapidly prior to synaptosome preparation. Synaptosomes were prepared in this manner from postmortem caudate nucleus tissue obtained from normal humans 1 month to 63 years of age. To determine the relative number of DA nerve terminals for each individual, dopaminergic synaptosomes were selectively labeled with a monoclonal antibody to TH and quantified by fluorescence-activated cell sorting. To determine the relative amount of TH protein for each individual, the concentration of TH protein in the same synaptosomal preparations was determined using immunoblots. Our results suggest that caudate TH levels plateau soon after birth and tend to remain relatively stable during aging, since no changes in either the relative number of TH-containing nerve terminals or the concentration of TH protein were found in subjects 15-63 years of age. In light of previous studies showing an age-related loss of DA cell bodies, these findings suggest that remaining DA neurons compensate to maintain caudate levels of TH protein and TH-containing nerve terminals. Immunoblot studies identified three forms of TH monomer (60.6, 61.7, and 65.1 kDa), indicating that mRNAs coding for high molecular mass forms of TH may be actively translated in human brain. No age-related differences in the relative abundance of these forms were found. 相似文献
39.
Edward G. Shaskan Bruce J. Brew Marc Rosenblum Randall M. Thompson Richard W. Price 《Journal of neurochemistry》1992,59(4):1541-1546
Postmortem levels of native neopterin (D-erythro-neopterin) were measured in cerebral cortical samples from 44 human immunodeficiency virus type 1-infected and eight uninfected, nonneurological control patients. Cerebral cortical gray and white matter neopterin levels for the controls ranged from 0.5 to 7.2 pmol/mg of protein in contrast to neopterin levels in brains of the virus-infected patients, which frequently were more than threefold and occasionally more than 30-fold higher than mean control levels. Cortical neopterin levels did not correlate with severity of the acquired immunodeficiency syndrome dementia complex, but subcortical levels correlated with the presence of active human immunodeficiency virus type 1 infection, as reflected by pathological evidence of multinucleated giant cell encephalitis. Evidence of opportunistic cytomegalovirus infections in approximately 25% of the human immunodeficiency virus type 1-infected patients was associated with enhanced levels of neopterin in frontal cortex. 相似文献
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