349 research outputs found
STUDIES WITH DROSOPHILA MELANOGASTER: A THE EFFECT OF POLYAMINES UPON RNA SYNTHESIS B L-ORNITHINE AND S-ADENOSYL-L-METHIONINE DECARBOXYLASE C THERMOLABILITY OF RNA
Instruct. Influence. Inspire: The Blended Librarian and Schools
Blended learning is an integration of traditional and online instruction that provides educational opportunities to facilitate student achievement. An important aspect of blended learning is to ensure flexible access to library resources for both teachers and students. This presentation focuses on how Putnam County secondary school libraries provide resources and services that support blended learning. The session will emphasize methods to embed research into blended learning and will also incorporate tips, modeling and best practices that the librarians have found to be successful at various depths of integration
Acute hypoxia increases ornithine decarboxylase activity and polyamine concentrations in fetal rat brain.
Progressive Visceral Leishmaniasis Is Driven by Dominant Parasite-induced STAT6 Activation and STAT6-dependent Host Arginase 1 Expression
The clinicopathological features of the hamster model of visceral leishmaniasis (VL) closely mimic active human disease. Studies in humans and hamsters indicate that the inability to control parasite replication in VL could be related to ineffective classical macrophage activation. Therefore, we hypothesized that the pathogenesis of VL might be driven by a program of alternative macrophage activation. Indeed, the infected hamster spleen showed low NOS2 but high arg1 enzyme activity and protein and mRNA expression (p<0.001) and increased polyamine synthesis (p<0.05). Increased arginase activity was also evident in macrophages isolated from the spleens of infected hamsters (p<0.05), and arg1 expression was induced by L. donovani in primary hamster peritoneal macrophages (p<0.001) and fibroblasts (p<0.01), and in a hamster fibroblast cell line (p<0.05), without synthesis of endogenous IL-4 or IL-13 or exposure to exogenous cytokines. miRNAi-mediated selective knockdown of hamster arginase 1 (arg1) in BHK cells led to increased generation of nitric oxide and reduced parasite burden (p<0.005). Since many of the genes involved in alternative macrophage activation are regulated by Signal Transducer and Activator of Transcription-6 (STAT6), and because the parasite-induced expression of arg1 occurred in the absence of exogenous IL-4, we considered the possibility that L. donovani was directly activating STAT6. Indeed, exposure of hamster fibroblasts or macrophages to L. donovani resulted in dose-dependent STAT6 activation, even without the addition of exogenous cytokines. Knockdown of hamster STAT6 in BHK cells with miRNAi resulted in reduced arg1 mRNA expression and enhanced control of parasite replication (p<0.0001). Collectively these data indicate that L. donovani infection induces macrophage STAT6 activation and STAT6-dependent arg1 expression, which do not require but are amplified by type 2 cytokines, and which contribute to impaired control of infection
Ornithine decarboxylase and polyamine levels are reduced in CHO cells deficient in cAMP-dependent protein kinase
The induction of ornithine decarboxylase by tumor promoting phorbol ester analogues in Reuber H35 hepatoma cells
Ornithine dec arboxylaseβapparent lack of involvement in the induction of n-acetyltransferase in rat pineal gland
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