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31.
Spániková A Simoncíková P Ravingerová T Pechánová O Barancík M 《Molecular and cellular biochemistry》2008,312(1-2):113-120
The aim of the present study was to characterize the effects of chronic nitric oxide synthase (NOS) inhibition on the alterations
of regulatory myocardial proteins of intracellular signaling pathways (mitogen-activated protein kinase (MAPK) and Akt kinase
cascades) and matrix metalloproteinases (MMP). Chronic NO deficiency (NOD) was induced by NG-nitro-L-arginine methyl ester (L-NAME, 40mg/kg/day, 4 weeks). Protein levels and activation of protein kinases were determined
using specific antibodies, activities of MMP were analyzed by zymography in gels containing gelatin as a substrate. The development
of NOD was associated with decreased activation of endothelial NOS (eNOS) and down-regulation of protein level of inducible
NOS (iNOS). Investigation of kinase pathways revealed that the activation of extracellular signal-regulated kinases (ERK)
and the levels of upstream activators of ERK (aFGF, H-Ras) were decreased after L-NAME treatment. Western blot analysis revealed
that chronic application of L-NAME also decreased the activation of Akt kinase as compared with control hearts. Study of MMPs
showed that in L-NAME-treated rat hearts activities of tissue MMP-2 were decreased. It is concluded that development of NOD
resulted in inhibition of ERK and Akt kinase pathways and these changes suggest the involvement of these cascades in responses
of myocardium to NOD. The results also point to the possible relationship between ERK and Akt kinase pathways and activation
of eNOS and/or MMP-2.
Anna Špániková and Petra Šimončíková have contributed equally to the study. 相似文献
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The partitioning of limited resources commonly explains how different species can coexist within the same ecological community. In this 2010 study, the diets of three coexisting freshwater fishes (Cape galaxias Galaxias zebratus, n = 27; Cape kurper Sandelia capensis, n = 60; Breede River redfin Pseudobarbus burchelli, n = 77) were characterised and compared in three headwater streams in South Africa's Cape Fold Ecoregion using gut contents and stable isotope analyses. These data were analysed to ascertain whether the three species exploit distinct trophic niches. Both approaches provided evidence that these species occupy different trophic niches, though with some overlap. However, dietary differences among sites were not consistent and were probably influenced by site-specific factors like resource availability. Pseudobarbus burchelli had a broader niche breadth at Tierkloof Stream than the other two species, but not at Waaihoek or Tierstel Streams. Our results also suggest that P. burchelli consumed a more omnivorous diet than do the other two species, whereas S. capensis occupied a higher trophic position than the other two species and consumed vertebrates. Our findings suggest that these species occupy non-equivalent feeding niches in Cape Fold Ecoregion headwater streams, and that diet partitioning might facilitate their coexistence in these systems. 相似文献
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Tischler JL Abuaita B Cuthpert SC Fage C Murphy K Saxe A Furr EB Hedrick J Meyers J Snare D Zand AR 《Journal of enzyme inhibition and medicinal chemistry》2008,23(4):549-555
Butyric acid and trichostatin A (TSA) are anti-cancer compounds that cause the upregulation of genes involved in differentiation and cell cycle regulation by inhibiting histone deacetylase (HDAC) activity. In this study we have synthesized and evaluated compounds that combine the bioavailability of short-chain fatty acids, like butyric acid, with the bidentate binding ability of TSA. A series of analogs were made to examine the effects of chain length, simple aromatic cap groups, and substituted hydroxamates on the compounds' ability to inhibit rat-liver HDAC using a fluorometric assay. In keeping with previous structure-activity relationships, the most effective inhibitors consisted of longer chains and hydroxamic acid groups. It was found that 5-phenylvaleric hydroxamic acid and 4-benzoylbutyric hydroxamic acid were the most potent inhibitors with IC50's of 5 microM and 133 microM respectively. 相似文献