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171.
172.
Benign prostatic hyperplasia (BPH) is the most common adenoma in old men. Tomatoes are a rich source of bioactive compounds that, as well as selenium (Se), possess antioxidant and antiproliferative activity. The aim was to evaluate the therapeutic effect of Se in combination with a tomato extract in aged rats with BPH. Aged male Wistar rats were divided in the following groups (n = 10 rats/group): Control (C), BPH, BPH + Finasteride (BPH + F), BPH + Tomato Lipidic Extract (BPH + E), BPH + Selenium (BPH + S) and BPH plus E plus S (BPH + E + S). After 4 weeks of treatment, prostate weight, diuresis, antioxidants enzymes, prooxidants and inflammatory markers, growth factors and androgens were determined. BPH + E + S reduced prostate weight by 59.29% and inhibited growth by 99.35% compared to BPH + F which only decreased weight and inhibited growth by 15.31% and 57.54%, respectively. Prooxidant markers were higher with BPH + F (49.4% higher vs. BPH), but BPH + E + S decreased these markers (94.27% vs. BPH) and increased antioxidant activity. Finally, diuresis was higher with the BPH + E + S combination and markers of inflammation and growth factors were significantly lower with respect to BPH + F. Our findings provide a beneficial and protective therapeutic option of E + S directed against androgens, oxidative stress and inflammation that regulates cell proliferation in the prostate gland.  相似文献   
173.
A pair of -cyano analogues of decarboxylated S-adenosylmethionine (2a and 2b) were synthesized as potential enzyme activated, irreversible inhibitors of the[pyruvoyl enzyme S-adenosylmethionine decarboxylase (AdoMet-DC). Each of these analogues acts as an irreversible inactivator for ADoMet-DC from Escherichia coli (IC50 values of 9 and 50 μM, respectively). These analogues also inactivate human AdoMet-DC, with KI values of 246.6 and 7.2 μM, and kinact values of 0.29 and 0.03 min−1, respectively.  相似文献   
174.
The conformationally restricted S-adenosylmethionine analogue AdoMac (S-(5′-deoxy-5′-adenosyl)-1-ammonio-4-methylsulfonio-2-cyclopentene has been shown to act as an enzyme activated, irreversible inhibitor of theEscherichia coli form of the enzyme S-adenosylmethionine decarboxylase. Inactivation of the enzyme is presumably initiated by formation of an imine linkage between the inhibitor and the terminal pyruvate of the enzyme, followed by base-catalyzed elimination of methylthioadenosine and generation of a latent electrophile. Removal of the driving force for the elimination of methylthioadenosine resulted in a reversibly binding inhibitor. Thus, the thioether analogue corresponding to AdoMac, and the corresponding dihydro derivative (H2-AdoMac), reversibly inhibit the enzyme. AdoMac was resolved into its four pure diastereomeric forms, and each diastereomer was evaluated as an irreversible inhibitor of the enzyme. The KI values for the individual diastereomers range between 3.83 and 39.6 μM, with the cis-1S,4R diastereomer being the most potent inhibitor. However, the kinact values for the four diastereomers are not significantly different, suggesting that the binding of each diastereomer to the enzyme is configuration-dependent, while the subsequent inactivation likely proceeds through a single intermediate which is formed from each of the four diastereomers. Since each pure diastereomer represents a distinct conformational mimic exhibiting restricted sidechain rotation, the data suggests that these and related analogues may be useful as conformational probes for the catalytic site of AdoMet-DC.  相似文献   
175.
The soluble proteins of the eggs of the coleopteran insect Anthonomus grandis Boheman, the cotton boll weevil, consist almost entirely of two vitellin types with Mrs of 160,000 and 47,000. We sequenced their N-terminal ends and one internal cyanogen bromide fragment of the large vitellin and compared these sequences with the deduced amino acid sequence from the vitellogenin gene. The results suggest that both the boll weevil vitellin proteins are products of the proteolytic cleavage of a single precursor protein. The smaller 47,000 M vitellin protein is derived from the N-terminal portion of the precursor adjacent to an 18 amino acid signal peptide. The cleavage site between the large and small vitellins at amino acid 362 is adjacent to a pentapeptide sequence containing two pairs of arginine residues. Comparison of the boll weevil sequences with limited known sequences from the single 180,000 Mr honey bee protein show that the honey bee vitellin N-terminal exhibits sequence homology to the N-terminal of the 47,000 Mr boll weevil vitellin. Treatment of the vitellins with an N-glycosidase results in a decrease in molecular weight of both proteins, from 47,000 to 39,000 and from 160,000 to 145,000, indicating that about 10–15% of the molecular weight of each vitellin consists of N-linked carbohydrate. The molecular weight of the deglycosylated large vitellin is smaller than that predicted from the gene sequence, indicating possible further proteolytic processing at the C-terminal of that protein. © 1993 Wiley-Liss, Inc.
  • 1 This article is a US Government work and, as such, is in the public domain in the United States of America.
  •   相似文献   
    176.
    Macrophage colony stimulating factor (CSF-1) and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are potent inducers of macrophage differentiation. Both appear to modulate protein phosphorylation, at least in part, through protein kinase C (PKC) raising the question as to whether they concurrently impact on macrophage-like cells. In this regard, we utilized the CSF-1 dependent murine macrophage-like line BAC 1.25F5. CSF-1 treatment of these cells for 30 min leads to particular phosphorylation of a 165 kDa protein, the putative CSF-1 receptor, and a 210 kDa moiety. 1,25(OH)2D3 exposure for 24 h prior to addition of CSF-1 enhances phosphorylation of the 165 kDa species and, especially, the 210 kDa protein. Phosphorylation of the latter protein is 1,25(OH)2D3 dose- and time-dependent and the molecule is specifically immunoprecipitated with a rabbit polyclonal anti-talin antibody. Experiments with okadaic acid show that the enhanced phosphorylation of talin does not result from serine phosphatase inhibition. CSF-1 and 1,25(OH)2D3, alone or in combination, do not increase talin protein expression. The tyrosine kinase inhibitor, genestein, blocks 1,25(OH)2D3/CSF-1 induced phosphorylation of the putative CSF-1 receptor but has no effect on talin phosphorylation which occurs exclusively on serine. In contrast to genestein, staurosporin, an inhibitor of PKC, inhibits phosphorylation of talin. Moreover, exposure of 1,25(OH)2D3 pretreated cells to phorbol 12-myristate 13-acetate (PMA) in place of CSF-1 also prompts talin phosphorylation. Finally, 1,25(OH)2D3 enhances 3[H]PDBu binding, indicating that the steroid increases PMA receptor capacity. Thus, CSF-1 and 1,25(OH)2D3 act synergistically via PKC to phosphorylate talin, a cytoskeletal-associated protein.  相似文献   
    177.
    Predator behaviors influence, and are influenced by, prey and competitor behaviors. Jaguars (Panthera onca), pumas (Puma concolor), and ocelots (Leopardus pardalis) coexist throughout their geographic range as the three largest predators in a multi-predator community across diverse environments. This study tested for non-random segregation and overlap in the activity patterns of these felids and their shared prey in the southern buffer zone of the Calakmul Biosphere Reserve, in southern Mexico, using camera traps during February to August 2019. We detected little temporal segregation between the nocturnal activities of jaguars, pumas, and ocelots, although pumas were more active closer to dawn. Jaguars had low activity overlap with species likely to be common prey, whereas ocelots had high overlap with their potential prey. Pumas displayed finer-scale similarities in activity with species likely to be common prey. In an understudied area of conservation importance, this study shows that temporal segregation is an unlikely mechanism of coexistence. Further research should incorporate spatio-temporal avoidance and dietary differences to improve our understanding of the mechanisms that drive coexistence between generalist species in a diverse assemblage of threatened felids. Abstract in Spanish is available with online material.  相似文献   
    178.
    Native toxic shock syndrom toxin 1 (TSST-1) purified from Staphylococcus aurius has been crystallized in four different forms. The highest resolution data (2.05 Å) was collected from orthorhombic crystals belonging to the space group C2221. The unit cell dimension are a = 108.7 Å, b = 177.5 Å, c = 97.6 Å. Rotation function analysis of this from indicates that there is trimer of toxin molecules in the asymmetric unit with a local 3-fold axis parallel to the crystallographic c axis. Crystals of a double mutant of TSST-1 have been grown which has a single molecule in the asymmetric unit and diffract to 1.9 Å. The space group is P21 with unit cell parameters of a = 44.4 Å, b = 34.0 Å, c = 55.2 Å, β = 93.0°. © 1993 Wiley-Liss, Inc.  相似文献   
    179.
    In order to cope with the increasing number of publications on the separation of enantiomers by chromatography on a chiral stationary phase, the graphical molecular database CHIRBASE was created. In the present state, the database package covers information (structural, bibiographic, and chromatographic data) on liquid-, supercritical fluid-, and gas chromatography; other methods will follow. CHIRBASE, running on the MDL software Chembase®, meets the requirements of contemporary information management in the chemical and pharmaceutical industry. (Detailed information including a demo-version of each part of CHIRBASE can be obtained from the authors on request.) © 1993 Wiley-Liss, Inc.  相似文献   
    180.
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