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11.
For the first time, endogenous amounts of Leu-enkephalin are measured in brain tissue with a technique preserving integrity of the entire molecular structure of the neuropeptide. Field-desorption mass spectrometry enables measurement of picomole amounts of endogenous, chemically underivatized Leu-enkephalin in canine caudate nuclei and hypothalami. The optimal sensitivity and resolution of high-performance liquid chromatography is coupled with maximal molecular specificity of field-desorption mass spectrometry to measure enkephalins in caudate nuclei and hypothalami from dog brains. This novel combination of two recent instrumental methodologies provides a firm molecular basis for calibrating the radioimmunoassay measurement of endogenous levels of biologically active brain neuropeptides. 相似文献
12.
Jerry Lee Lovelace Jozef J. Kusmierz Dominic M. Desiderio 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1991,562(1-2)
Methionine enkephalin (ME = YGGFM) was measured in five individual human post-mortem pituitaries using four different analytical methods, with the objective of comparing the molecular specificities of the methods. Radioreceptor assay (RRA) used a receptor-rich preparation from brain and [3H]etorphine as radioligand to determine ME-like receptoractivity (ME-LR). Radioimmunoassay (RIA) measured ME-like immunoreactivity (ME-LI). Pituitary samples analyzed by RRA and RIA were purified first with a high-performance liquid chromatography (HPLC) gradient on a polymer analytical column. Fast atom bombardment mass spectrometry (FAB-MS) in two different detection modes quantified ME using the protonated molecular ion MH+ of ME at 574 a.m.u. and B/E linked-field selected reaction monitoring (SRM) to monitor the specific unimolecular metastable transition that produced the unique amino acid sequence-determining tetrapeptide fragment ion YGGF+ from the MH+ precursor ion. Both FAB-MS methods used the deuterated internal standard YGG[2H5-F]M. Samples analyzed with FAB-MS were purified first with multi-dimensional reversed-phase HPLC. The first dimension was an ODS gradient, and the second dimension was a polymer isocratic elution. The following ME amounts were measured (mean ± standard error of the mean): ME-LR, 7.0 ± 1.9 μg g−1 tissue; ME-LI, 1.8 ± 0.7 μg g−1 tissue; MH+, 2.7 ± 0.6 μg g−1 tissue; SRM, 3.0 ± 0.8 μg g−1 tissue. The FAB SRM method provided the highest level of molecular specificity amount these four analytical methods used to measure picomole amounts of endogenous ME in a human pituitary. 相似文献
13.
The presence of the stud male failed to prevent implantation failure in newly inseminated females induced by administration of bromocriptine. This is in contrast with the ability of the stud male to prevent implantation failure in females induced by alien male exposure, and nutritional stress. Since bromocriptine is a potent inhibitor of hypophysial prolactin release by virtue of its stimulatory effect on hypothalamic dopaminergic activity, the results suggest that the stud male-originating luteotrophic stimulus is incapable of overriding the dopaminergic activity in bromocriptine-treated females. 相似文献
14.
Patrick Y-K Wong Kafait U. Malik Dominic M. Desiderio John C. McGiff Frank F. Sun 《Biochemical and biophysical research communications》1980,93(2):486-494
Metabolism of [9-3H]-PGI2 was studied in the isolated Tyrode's perfused rabbit liver. Five products, four radioactive and one non-radioactive, were identified in the perfusate: 19-hydroxy-6-keto-PGF1α, 6-keto-PGF1α, dinor-6-keto-PGF1α, pentanor PGF1α and a 6-keto-PGE1-like substance. The first two, 19-hydroxy-6-keto-PGF1α and 6-keto-PGF1α, represented 5% and 45% respectively, of the total radioactivity; the last two accounted for 39%. The presence of dinor and pentanor derivatives of 6-keto-PGF1α indicated that β -oxidation and oxidative-decarboxylation occurs in the liver as the major metabolic pathway of PGI2. One non-radioactive metabolite which co-migrated with authentic 6-keto-PGE1 was found to inhibit platelet aggregation, having a potency similar to authentic 6-keto-PGE1, and its effect can be eliminated by boiling and by alkali treatment. This metabolite, having similar Rf value on TLC and biological behavior as 6-keto-PGE1, may arise from oxidation of 6-keto-PGF1α via the 9-hydroxyprostaglandin dehydrogenase pathway, as suggested by recovery of tritiated water in the aqueous phase of the perfusate. This material, a potent inhibitor of platelet aggregation, may arise from PGI2 or its hydrolysis product, 6-keto-PGF1α. 相似文献
15.
Control of chromosome condensation in the sea urchin egg 总被引:3,自引:0,他引:3
16.
Vijay K. Mahajan Dominic M. Desiderio 《Biochemical and biophysical research communications》1978,82(4):1104-1110
The amino acid sequence of oligopeptides can be determined from the mass spectra of their volatile derivatives. New peptide derivatives are described which are prepared from permethylated peptides by reduction with borane-tetrahydrofuran. These derivatives have been found to be more volatile than the corresponding permethylated ones. The procedure is illustrated by application of this technique to representative oligopeptides. As little as 10–100 nmol of these peptides have been sequenced using this technique. 相似文献
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Olivo Miotto Makoto Sekihara Shin-Ichiro Tachibana Masato Yamauchi Richard D. Pearson Roberto Amato Sonia Gonalves Somya Mehra Rintis Noviyanti Jutta Marfurt Sarah Auburn Ric N. Price Ivo Mueller Mie Ikeda Toshiyuki Mori Makoto Hirai Livingstone Tavul Manuel W. Hetzel Moses Laman Alyssa E. Barry Pascal Ringwald Jun Ohashi Francis Hombhanje Dominic P. Kwiatkowski Toshihiro Mita 《PLoS pathogens》2020,16(12)
The rapid and aggressive spread of artemisinin-resistant Plasmodium falciparum carrying the C580Y mutation in the kelch13 gene is a growing threat to malaria elimination in Southeast Asia, but there is no evidence of their spread to other regions. We conducted cross-sectional surveys in 2016 and 2017 at two clinics in Wewak, Papua New Guinea (PNG) where we identified three infections caused by C580Y mutants among 239 genotyped clinical samples. One of these mutants exhibited the highest survival rate (6.8%) among all parasites surveyed in ring-stage survival assays (RSA) for artemisinin. Analyses of kelch13 flanking regions, and comparisons of deep sequencing data from 389 clinical samples from PNG, Indonesian Papua and Western Cambodia, suggested an independent origin of the Wewak C580Y mutation, showing that the mutants possess several distinctive genetic features. Identity by descent (IBD) showed that multiple portions of the mutants’ genomes share a common origin with parasites found in Indonesian Papua, comprising several mutations within genes previously associated with drug resistance, such as mdr1, ferredoxin, atg18 and pnp. These findings suggest that a P. falciparum lineage circulating on the island of New Guinea has gradually acquired a complex ensemble of variants, including kelch13 C580Y, which have affected the parasites’ drug sensitivity. This worrying development reinforces the need for increased surveillance of the evolving parasite populations on the island, to contain the spread of resistance. 相似文献