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Protein Synthesis Inhibition (protein + synthesis_inhibition)
Selected AbstractsHistone H1 and MAP Kinase Activities in Bovine Oocytes following Protein Synthesis InhibitionREPRODUCTION IN DOMESTIC ANIMALS, Issue 3-4 2001B Meinecke In vitro nuclear maturation is associated with known activity profiles of the M-phase promoting factor (MPF) and the mitogen-activated protein (MAP) kinases, which are two key regulators of mitotic and meiotic cell cycles. Initiation of meiotic resumption in vitro can be prevented by cycloheximide treatment and after removal of the inhibitor germinal vesicle breakdown takes place nearly twice as fast as in untreated controls. In this study experiments were conducted in order to examine the chromosome condensation status and the dynamics of MPF and MAP kinase activities after cycloheximide treatment (10 ,g/ml) of cumulus-enclosed oocytes for 17 and 24 h, respectively, and subsequent culture in inhibitor-free medium for various times. Bovine oocytes displayed variations in the degree of chromosome condensation at the end of the inhibitor treatment phase. Following removal of the inhibitor germinal vesicle breakdown occurred after 4,5 h of subsequent culture in inhibitor-free medium. MPF and MAP kinase exhibited low activities during the first 1,3 h following cycloheximide treatment. Increasing levels of enzyme activities were detected 4,7 h following cycloheximide treatment for 17 and 24 h, respectively, and subsequent culture in inhibitor-free medium. The patterns of enzyme activities corresponded with the accelerated nuclear maturation process. It can be concluded that cycloheximide treatment does not lead to a more synchronous course of nuclear maturation and that the activities of both, MPF and MAP kinase are initiated at least 2,5 h earlier in comparison with untreated oocytes. [source] Protein synthesis inhibition before or after stress exposure results in divergent endocrine and BDNF responses disassociated from behavioral responsesDEPRESSION AND ANXIETY, Issue 5 2008Nitsan Kozlovsky Ph.D. Abstract This study aimed to assess the effects of anisomycin, a protein synthesis inhibitor, on behavioral responses, brain-derived neurotrophic factor (BDNF) and TrkB mRNA levels, and circulating corticosterone in rats,when administered before or after initial exposure to a predator scent stress stimulus. Magnitude of changes in prevalence of anxiety-like behaviors on the elevated plus-maze and exaggerated startle reaction as well as corticosterone levels and mRNA BDNF and TrkB were compared in rats exposed to predator stress, microinjected with anisomycin before or after stress exposure. Administration of anisomycin before or after stress exposure reduced anxiety-like behavior in the elevated plus-maze and reduced the mean startle amplitude 7 days postexposure. Although the behavioral responses were similar when anisomycin was microinjected before or after stress exposure, the levels of mRNAs for BDNF and TrkB, which play a role in modulation of synaptic plasticity and the consolidation process, showed varying responses. Depression and Anxiety 0:1,11, 2007. © 2007 Wiley-Liss, Inc. [source] 2-Deoxyglucose and NMDA inhibit protein synthesis in neurons and regulate phosphorylation of elongation factor-2 by distinct mechanismsJOURNAL OF NEUROCHEMISTRY, Issue 3 2006M. Maus Abstract Cerebral ischaemia is associated with brain damage and inhibition of neuronal protein synthesis. A deficit in neuronal metabolism and altered excitatory amino acid release may both contribute to those phenomena. In the present study, we demonstrate that both NMDA and metabolic impairment by 2-deoxyglucose or inhibitors of mitochondrial respiration inhibit protein synthesis in cortical neurons through the phosphorylation of eukaryotic elongation factor (eEF-2), without any change in phosphorylation of initiation factor eIF-2,. eEF-2 kinase may be activated both by Ca2+ -independent AMP kinase or by an increase in cytosolic Ca2+. Although NMDA decreases ATP levels in neurons, only the effects of 2-deoxyglucose on protein synthesis and phosphorylation of elongation factor eEF-2 were reversed by Na+ pyruvate. Protein synthesis inhibition by 2-deoxyglucose was not as a result of a secondary release of glutamate from cortical neurons as it was not prevented by the NMDA receptor antagonist 5-methyl-10,11-dihydro-5H-dibenzo-(a,d)-cyclohepten-5,10-imine hydrogen maleate (MK 801), nor to an increase in cytosolic-free Ca2+. Conversely, 2-deoxyglucose likely activates eEF-2 kinase through a process involving phosphorylation by AMP kinase. In conclusion, we provide evidence that protein synthesis can be inhibited by NMDA and metabolic deprivation by two distinct mechanisms involving, respectively, Ca2+ -dependent and Ca2+ -independent eEF-2 phosphorylation. [source] Effects of locomotor stimulation and protein synthesis inhibition on circadian rhythms in size changes of L1 and L2 interneurons in the fly's visual systemDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2007Elzbieta Kula Abstract Axons of monopolar cell interneurons L1 and L2 in the first optic lobe (lamina) of the fly Musca domestica undergo cyclical changes in diameter. These axons swell during the day and shrink during the night. In addition, the axons' size depends on light conditions since they are largest in continuous light (LL), somewhat smaller under day/night (LD) conditions, and smallest under constant darkness (DD). In this study we found that sizes of both cells can further increase in free flying flies under LD conditions, while the visual stimulation alone does not have significant effect on the cross-sectional area of L1 and L2 axons. The stimulation of free flying had no effect on L1 and L2 sizes if it was performed at the beginning of subjective day in LL or DD. Our results indicate that a maximal increase in size of L1 and L2 is observed when stimulation of free flying is synchronized with a fly' daily peak of activity. We also found that protein synthesis is needed to increase size of monopolar cell axons during the day when they normally swell. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007. [source] From learning to forgetting: Behavioral, circuitry, and molecular properties define the different functional states of the recognition memory traceHIPPOCAMPUS, Issue 5 2010Rocío Romero-Granados Abstract Neuropsychological analyses of amnesic patients, as well as lesion experiments, indicate that the temporal lobe is essential for the encoding, storage, and expression of object recognition memory (ORM). However, temporal lobe structures directly involved in the consolidation and reconsolidation of these memories are not yet well-defined. We report here that systemic administration of a protein synthesis inhibitor before or up to 4 h after training or reactivation sessions impairs consolidation and reconsolidation of ORM, without affecting short-term memory. We have also observed that ORM reconsolidation is sensitive to protein synthesis inhibition, independently of the ORM trace age. Using bdnf and egr-1 gene expression analysis, we defined temporal lobe areas related to consolidation and reconsolidation of ORM. Training and reactivation 21 days after ORM acquisition sessions provoked changes in bdnf mRNA in somatosensory, perirhinal, and hippocampal cortices. Reactivation 2 days after the training session elicited changes in bdnf and egr-1 mRNA in entorhinal and prefrontal cortices, while reactivation 9 days post-training provoked an increase in egr-1 transcription in somatosensory and entorhinal cortices. The differences in activated circuits and in the capacity to recall the memory trace after 9 or 21 days post-training suggest that memory trace suffers functional changes in this period of time. All these results indicate that the functional state of the recognition memory trace, from acquisition to forgetting, can be specifically defined by behavioral, circuitry, and molecular properties. © 2009 Wiley-Liss, Inc. [source] The Role of Cytokines in Regulating Protein Metabolism and Muscle FunctionNUTRITION REVIEWS, Issue 2 2002Elena Zoico M.D. Multiple lines of evidence suggest that cytokines influence different physiologic functions of skeletal muscle cells, including anabolic and catabolic processes and programmed cell death. Cytokines play an important role not only in muscle homeostasis, therefore, but also in the pathogenesis of different relevant clinical conditions characterized by alterations in protein metabolism. Recently discovered cytokines, such as ciliary neurotrophic factor and growth/differentiation factor-8, as well as the more studied tumor necrosis factor-,, interleukin-1, interleukin-6, and the interferons, have been implicated in the regulation of muscle protein turnover. Their postreceptor signaling pathways, proteolytic systems, and the mechanisms of protein synthesis inhibition involved in different catabolic conditions have been partially clarified. Moreover, recent studies have shown that cytokines can directly influence skeletal muscle contractility independent of changes in muscle protein content. Even though several gaps remain in our understanding, these observations may be useful in the development of strategies to control protein metabolism and muscle function in different clinical conditions. [source] | |||||||||||||