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81.
The role of protein in the estrogen-stimulated in vitro RNA synthesis of isolated rat uterine nucleoli 总被引:3,自引:0,他引:3
Immature rat uterine nucleoli were isolated and their ability to synthesize RNA in vitro was determined. Estradiol-17β injected intraperitoneally 2 hr prior to killing stimulated rat uterine nucleolar in vitro RNA synthesis both quantitatively and qualitatively. The intraperitoneal administration of cycloheximide as late as 10 min prior to the end of a 2-hr estrogen exposure prevented both the quantitative and qualitative changes stimulated by estrogen. The data suggest that estrogen-stimulated rat uterine nucleolar RNA synthesis requires the continuous synthesis of protein. 相似文献
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83.
Fisher SZ Tariku I Case NM Tu C Seron T Silverman DN Linser PJ McKenna R 《Biochimica et biophysica acta》2006,1764(8):1413-1419
Carbonic anhydrases (CAs) are zinc-containing metalloenzymes that catalyze the interconversion of carbon dioxide and bicarbonate. The alpha-class CAs are found predominantly in vertebrates, but they are also expressed in insects like mosquitoes. Recently, an alpha-CA from the midgut of Aedes aegypti larvae (AaCA1) was identified, cloned, and subsequently shown to share high sequence homologous to human CA I (HCA I). This paper presents the bacterial expression, purification, and kinetic characterization of the soluble CA domain of AaCA1. The data show AaCA1 is a highly active CA that displays inhibition by methazolamide and ethoxzolamide with nM affinity. Additionally, a homology model of AaCA1, based on the crystal structure of HCA I, is presented and the overall structure, active site, and surface charge properties are compared to those of HCA I and II. Measurements of catalysis show that AaCA1 is more like HCA II in terms of proton transfer, but more similar to HCA I in terms of conversion of carbon dioxide to bicarbonate, and these differences are rationalized in terms of structure. These results also indicate that amino acid differences in the active site of AaCA1 compared to human CAs could be used to design specific CA inhibitors for the management of mosquito populations. 相似文献
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Xenia Latypova Marie Vincent Alice Mollé Oluwadamilare A. Adebambo Cynthia Fourgeux Tahir N. Khan Alfonso Caro Monica Rosello Carmen Orellana Dmitriy Niyazov Damien Lederer Marie Deprez Yline Capri Peter Kannu Anne Claude Tabet Jonathan Levy Emmelien Aten Nicolette den Hollander Bertrand Isidor 《American journal of human genetics》2021,108(5):929-941
86.
Wojciech G. Lesniak Amar Jyoti Manoj K. Mishra Nicolette Louissaint Roberto Romero Diane C. Chugani Sujatha Kannan Rangaramanujam M. Kannan 《Analytical biochemistry》2013
An imbalance in tryptophan (TRP) metabolites is associated with several neurological and inflammatory disorders. Therefore, analytical methods allowing for simultaneous quantification of TRP and its major metabolites would be highly desirable, and may be valuable as potential biomarkers. We have developed a HPLC method for concurrent quantitative determination of tryptophan, serotonin, 5-hydroxyindoleacetic acid, kynurenine, and kynurenic acid in tissue and fluids. The method utilizes the intrinsic spectroscopic properties of TRP and its metabolites that enable UV absorbance and fluorescence detection by HPLC, without additional labeling. The origin of the peaks related to analytes of interest was confirmed by UV–Vis spectral patterns using a PDA detector and mass spectrometry. The developed methods were validated in rabbit fetal brain and amniotic fluid at gestational day 29. Results are in excellent agreement with those reported in the literature for the same regions. This method allows for rapid quantification of tryptophan and four of its major metabolites concurrently. A change in the relative ratios of these metabolites can provide important insights in predicting the presence and progression of neuroinflammation in disorders such as cerebral palsy, autism, multiple sclerosis, Alzheimer disease, and schizophrenia. 相似文献
87.
A new and sensitive high performance liquid chromatography (HPLC) separation procedure coupled with tandem mass spectroscopy (MS and MS(2)) detection was developed to identify for the first time the oxidation products of 5β-scymnol [(24R)-(+)-5β-cholestan-3α,7α,12α,24,26,27-hexol] catalysed by bacterial hydroxysteroid dehydrogenase (HSD) reactions in vitro. The authentic scymnol (MW 468) standard yielded a protonated molecular ion [M+H](+) at m/z 469 Da, and higher mass adduct ions attributed to [M+NH(4)](+) (m/z 486), [M+H+CH(3)OH](+) (m/z 501) and [M+H+CH(3)COOH](+) (m/z 530). (24R)-(+)-5β-Cholestan-3-one-7α,12α,24,26,27-pentol (3-oxoscymnol, m/z 467 Da, relative retention time (RRT)=0.89) was identified as the principle molecular species of scymnol in the reaction with 3α-HSD pure enzyme. [S](0.5) for the reaction of 3α-HSD with scymnol as substrate was 0.7292 mM. (24R)-(+)-5β-cholestan-7-one-3α,12α,24,26,27-pentol (7-oxoscymnol, m/z 467 Da, RRT=0.79) and (24R)-(+)-5β-cholestan-12-one-3α,7α,24,26,27-pentol (12-oxoscymnol, m/z 467 Da, RRT=0.81) were similarly identified as principle molecular species in the respective 7α-HSD and 12α-HSD reactions. Polarity of the oxoscymnol species was established as 7-oxoscymnol>12-oxoscymnol>3-oxoscymnol>scymnol (in order from most polar to least polar). Confirmation that 5β-scymnol is an oxidative substrate for steroid-metabolising enzymes was made possible by the use of sophisticated liquid chromatography-mass spectrometry (LC-MS) techniques that will likely provide the basis for further exploration of scymnol as a therapeutic compound. 相似文献
88.
When examining the structural identifiability properties of dynamic system models, some parameters can take on an infinite number of values and yet yield identical input-output data. These parameters and the model are then said to be unidentifiable. Finding identifiable combinations of parameters with which to reparameterize the model provides a means for quantitatively analyzing the model and computing solutions in terms of the combinations. In this paper, we revisit and explore the properties of an algorithm for finding identifiable parameter combinations using Gröbner Bases and prove useful theoretical properties of these parameter combinations. We prove a set of M algebraically independent identifiable parameter combinations can be found using this algorithm and that there exists a unique rational reparameterization of the input-output equations over these parameter combinations. We also demonstrate application of the procedure to a nonlinear biomodel. 相似文献
89.
Gleeson M Bishop NC Stensel DJ Lindley MR Mastana SS Nimmo MA 《Nature reviews. Immunology》2011,11(9):607-615
Regular exercise reduces the risk of chronic metabolic and cardiorespiratory diseases, in part because exercise exerts anti-inflammatory effects. However, these effects are also likely to be responsible for the suppressed immunity that makes elite athletes more susceptible to infections. The anti-inflammatory effects of regular exercise may be mediated via both a reduction in visceral fat mass (with a subsequent decreased release of adipokines) and the induction of an anti-inflammatory environment with each bout of exercise. In this Review, we focus on the known mechanisms by which exercise - both acute and chronic - exerts its anti-inflammatory effects, and we discuss the implications of these effects for the prevention and treatment of disease. 相似文献
90.
Dezzutti CS Hendrix CW Marrazzo JM Pan Z Wang L Louissaint N Kalyoussef S Torres NM Hladik F Parikh U Mellors J Hillier SL Herold BC 《PloS one》2011,6(8):e23136