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Several Physiological Processes (several + physiological_process)
Selected AbstractsDisruption of insulin pathways alters trehalose level and abolishes sexual dimorphism in locomotor activity in DrosophilaDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2006Yesser Hadj Belgacem Abstract Insulin signaling pathways are implicated in several physiological processes in invertebrates, including the control of growth and life span; the latter of these has also been correlated with juvenile hormone (JH) deficiency. In turn, JH levels have been correlated with sex-specific differences in locomotor activity. Here, the involvement of the insulin signaling pathway in sex-specific differences in locomotor activity was investigated in Drosophila. Ablation of insulin-producing neurons in the adult pars-intercerebralis was found to increase trehalosemia and to abolish sexual dimorphism relevant to locomotion. Conversely, hyper-insulinemia induced by insulin injection or by over-expression of an insulin-like peptide decreases trehalosemia but does not affect locomotive behavior. Moreover, we also show that in the head of adult flies, the insulin receptor (InR) is expressed only in the fat body surrounding the brain. While both male and female InR mutants are hyper-trehalosemic, they exhibit similar patterns of locomotor activity. Our results indicate that first, insulin controls trehalosemia in adults, and second, like JH, it controls sex-specific differences in the locomotor activity of adult Drosophila in a manner independent of its effect on trehalose metabolism. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Plant,Water Relations of Kidney Bean Plants Treated with NaCl and Foliarly Applied GlycinebetaineJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2002C. M. L. Lopez Salinity is at present one of the most serious environmental problems influencing crop growth. It has been extensively demonstrated that salinity affects several physiological processes in the plant, including the plant,water relations of most salt-sensitive crops species. In this study, the effects of salinity on the plant,water relations of kidney bean (Phaseolus vulgaris L.) and the possibility that foliarly applied glycinebetaine improves these water relations are examined. Kidney bean plants were grown in a greenhouse and treated with 0, 30, 50 and 100 mM NaCl, combined with 0, 10 and 30 mM glycinebetaine in foliar applications. Increased salinity levels decreased stomatal conductance, photosynthetic rate, transpiration and leaf relative water content in the 30, 50 and 100 mM treatments relative to the control treatment. Glycinebetaine applications of 10 mM increased stomatal conductance at 50 mM NaCl, ameliorating significantly the effect of salinity on water relations through increases in the leaf relative water content. At 100 mM NaCl, 30 mM glycinebetaine applications in particular contributed to osmotic stress, and had an adverse effect on plants. Our experiment suggests that glycinebetaine can be used as an alternative treatment to reduce the effects of salt stress on the water relations of salt-sensitive plants, but only to limited salinity levels. Furthermore, the improvement in the water status of kidney beans was dose dependent, suggesting that the concentration of glycinebetaine essential for the survival of salt-sensitive plants is species specific and must be determined individually for each plant species. Pflanzen,Wasser-Beziehungen von NaCl-behandelten und mit Glycinbetain besprühten Blättern von Gartenbohnenpflanzen Versalzung ist zur Zeit eine der am meisten wirksamen Umweltprobleme im Hinblick auf das Wachstum von Kulturpflanzen. Es hat umfangreiche Untersuchungen gegeben, die Versalzungswirkungen in ihrem Einfluss auf zahlreiche physiologische Vorgänge in der Pflanze zu untersuchen; hierbei wurden auch die Pflanzen,Wasser-Beziehungen von hochsalzempfindlichen Pflanzenarten berück-sichtigt. In dieser Untersuchung wurden die Einflüsse der Versalzung auf die Pflanzen,Wasser-Beziehungen bei Buschbohnen (Phaseolus vulgaris L.) und die Möglichkeit über Blattbesprühungen mit Glycinbetain die Wasser-Beziehungen zu verbessern, untersucht. Die Buschbohnen wurden im Gewächshaus angezogen und mit 0, 30, 50 mM NaCl in Kombination mit 0, 10, 30 mM Glycinbetain Blattbehandlungen angezogen. Eine Erhöhung der Versalzung führte zu einer Abnahme der stomatären Konduktanz, der Photosyntheserate, der Transpiration und des relativen Blattwassergehaltes bei den Behandlungen mit 30, 50 und 100 mM im Vergleich zur Kontrolle. Glysinbetainanwendungen von 10mM erhöhten die stomatäre Konduktanz bei 50 mM NaCl und verbesserten signifikant den ungünstigen Einfluss der Versalzung auf die Wasser-Beziehungen über eine Erhöhung des relativen Blattwassergehaltes. Verwendung von 100 mM NaCl und 30 mM GB trug zu dem osmotischen Streß durch Versalzung bei und hatten einen ungünstigen Einfluss auf die Pflanzen. Unser Experiment weist darauf hin, dass Glycinbetain eine alternative Möglichkeit ist, um die Einflüsse des Salzstresses auf die Wasser-Beziehungen von salzempfindlichen Pflanzen abzuschwächen; es bestehen aber Begrenzungen bezüglich des Versalzungsgrades, bei denen eine günstige Wirkung nachgewiesen werden kann. Ausserdem ist die Verbesserung im Wasserzustand der Buschbohnen von der Anwendungsstärke abhängig, so dass die Konzentration von GB wesentlich für das Überleben der salzempfindlichen Pflanzenart spezifisch ist und für jede Pflanzenart untersucht werden. [source] Effects of Elevated CO2 on Growth, Carbon Assimilation, Photosynthate Accumulation and Related Enzymes in Rice Leaves during Sink-Source TransitionJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 6 2008Jun-Ying Li Abstract To study the effects of growing rice (Oryza sativa L.) leaves under the treatment of the short-term elevated CO2 during the period of sink-source transition, several physiological processes such as dynamic changes in photosynthesis, photosynthate accumulation, enzyme activities (sucrose phosphate synthase (SPS), and sucrose synthase (SS)), and their specific gene (sps1 and RSus1) expressions in both mature and developing leaf were measured. Rice seedlings with fully expanded sixth leaf (marked as the source leaf, L6) were kept in elevated (700 ,mol/mol) and ambient (350 mol/L) CO2 until the 7th leaf (marked as the sink leaf, L7) fully expanded. The results demonstrated that elevated CO2 significantly increased the rate of leaf elongation and biomass accumulation of L7 during the treatment without affecting the growth of L6. However, in both developing and mature leaves, net photosynthetic assimilation rate (A), all kinds of photosynthate contents such as starch, sucrose and hexose, activities of SPS and SS and transcript levels of sps1 and RSus1 were significantly increased under elevated CO2 condition. Results suggested that the elevated CO2 had facilitated photosynthate assimilation, and increased photosynthate supplies from the source leaf to the sink leaf, which accelerated the growth and sink-source transition in new developing sink leaves. The mechanisms of SPS regulation by the elevated CO2 was also discussed. [source] Chromogranins as regulators of exocytosisJOURNAL OF NEUROCHEMISTRY, Issue 2 2010Ricardo Borges J. Neurochem. (2010) 114, 335,343. Abstract Chromogranins (Cgs) constitute the main protein component in the vesicular matrix of large dense core vesicles (LDCV). These acidic proteins have been implicated in several physiological processes such as vesicle sorting, the generation of bioactive peptides and the accumulation of soluble species inside LDCV. This latter feature of Cgs accounts for the ability of vesicles to concentrate catecholamines and Ca2+. Indeed, the low affinity and high capacity of Cgs to bind solutes at the low pH of the LDCV lumen seems to be behind the delay in the neurotransmitter exit towards the extracellular milieu after vesicle fusion. The availability of new mouse strains lacking Cgs in combination with the arrival of several techniques for the direct monitoring of exocytosis (like amperometry, patch-amperometry and intracellular electrochemistry), have helped advance our understanding of how these granins concentrate catecholamines and Ca2+ in LDCV, and how they influence the kinetics of exocytosis. In this review, we will discuss the roles of Cgs A and B in maintaining the intravesicular environment of secretory vesicles and in exocytosis, bringing together the most recent findings from adrenal chromaffin cells. [source] | ||||||||||