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971.
Bicego KC Barros RC Branco LG 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,147(3):616-639
Few environmental factors have a larger influence on animal energetics than temperature, a fact that makes thermoregulation a very important process for survival. In general, endothermic species, i.e., mammals and birds, maintain a constant body temperature (Tb) in fluctuating environmental temperatures using autonomic and behavioural mechanisms. Most of the knowledge on thermoregulatory physiology has emerged from studies using mammalian species, particularly rats. However, studies with all vertebrate groups are essential for a more complete understanding of the mechanisms involved in the regulation of Tb. Ectothermic vertebrates-fish, amphibians and reptiles-thermoregulate essentially by behavioural mechanisms. With few exceptions, both endotherms and ectotherms develop fever (a regulated increase in Tb) in response to exogenous pyrogens, and regulated hypothermia (anapyrexia) in response to hypoxia. This review focuses on the mechanisms, particularly neuromediators and regions in the central nervous system, involved in thermoregulation in vertebrates, in conditions of euthermia, fever and anapyrexia. 相似文献
972.
Protoplasma - There is very scanty information concerning the floral nectary structure and nectar secretion in Prunus laurocerasus L. Therefore, the aim of the study was to determine the... 相似文献
973.
Antonina V. Pustovidko Tatiana I. Rokitskaya Inna I. Severina Ruben A. Simonyan Tatiana A. Trendeleva Konstantin G. Lyamzaev Yuri N. Antonenko Anton G. Rogov Renata A. Zvyagilskaya Vladimir P. Skulachev Boris V. Chernyak 《Mitochondrion》2013,13(5):520-525
Previously it has been shown by our group that berberine and palmatine, penetrating cations of plant origin, when conjugated with plastoquinone (SkQBerb and SkQPalm), can accumulate in isolated mitochondria or in mitochondria of living cells and effectively protect them from oxidative damage. In the present work, we demonstrate that SkQBerb, SkQPalm, and their analogs lacking the plastoquinone moiety (C10Berb and C10Palm) operate as mitochondria-targeted compounds facilitating protonophorous effect of free fatty acids. These compounds induce proton transport mediated by small concentrations of added fatty acids both in planar and liposomal model lipid membranes. In mitochondria, such an effect can be carried out by endogenous fatty acids and the adenine nucleotide translocase. 相似文献
974.
975.
Teresa Cristina Leandro de Jesus Renata Rosito Tonelli Sheila C. Nardelli Leonardo da Silva Augusto Maria Cristina M. Motta Wendell Girard-Dias Kildare Miranda Paul Ulrich Veronica Jimenez Antonio Barquilla Miguel Navarro Roberto Docampo Sergio Schenkman 《The Journal of biological chemistry》2010,285(31):24131-24140
Target of rapamycin (TOR) kinases are highly conserved protein kinases that integrate signals from nutrients and growth factors to coordinate cell growth and cell cycle progression. It has been previously described that two TOR kinases control cell growth in the protozoan parasite Trypanosoma brucei, the causative agent of African trypanosomiasis. Here we studied an unusual TOR-like protein named TbTOR-like 1 containing a PDZ domain and found exclusively in kinetoplastids. TbTOR-like 1 localizes to unique cytosolic granules. After hyperosmotic stress, the localization of the protein shifts to the cell periphery, different from other organelle markers. Ablation of TbTOR-like 1 causes a progressive inhibition of cell proliferation, producing parasites accumulating in the S/G2 phase of the cell cycle. TbTOR-like 1 knocked down cells have an increased area occupied by acidic vacuoles, known as acidocalcisomes, and are enriched in polyphosphate and pyrophosphate. These results suggest that TbTOR-like 1 might be involved in the control of acidocalcisome and polyphosphate metabolism in T. brucei. 相似文献
976.
Oxidation of tyrosine moieties by radicals involved in lipid peroxidation is of current interest; while a rate constant has been reported for reaction of lipid peroxyl radicals with a tyrosine model, little is known about the reaction between tyrosine and alkoxyl radicals (also intermediates in the lipid peroxidation chain reaction). In this study, the reaction between a model alkoxyl radical, the tert-butoxyl radical and tyrosine was followed using steady-state and pulse radiolysis. Acetone, a product of the β-fragmentation of the tert-butoxyl radical, was measured; the yield was reduced by the presence of tyrosine in a concentration- and pH-dependent manner. From these data, a rate constant for the reaction between tert-butoxyl and tyrosine was estimated as 6 ± 1 × 10(7) M(-1) s(-1) at pH 10. Tyrosine phenoxyl radicals were also monitored directly by kinetic spectrophotometry following generation of tert-butoxyl radicals by pulse radiolysis of solutions containing tyrosine. From the yield of tyrosyl radicals (measured before they decayed) as a function of tyrosine concentration, a rate constant for the reaction between tert-butoxyl and tyrosine was estimated as 7 ± 3 × 10(7) M(-1) s(-1) at pH 10 (the reaction was not observable at pH 7). We conclude that reaction involves oxidation of tyrosine phenolate rather than undissociated phenol; since the pK(a) of phenolic hydroxyl dissociation in tyrosine is ≈ 10.3, this infers a much lower rate constant, about 3 × 10(5) M(-1) s(-1), for the reaction between this alkoxyl radical and tyrosine at pH 7.4. 相似文献
977.
Andrea Comba Luciana L. Almada Ezequiel J. Tolosa Eriko Iguchi David L. Marks Marianela Vara Messler Renata Silva Maite G. Fernandez-Barrena Elisa Enriquez-Hesles Anne L. Vrabel Bruno Botta Lucia Di Marcotulio Volker Ellenrieder Aldo R. Eynard Maria E. Pasqualini Martin E. Fernandez-Zapico 《The Journal of biological chemistry》2016,291(4):1933-1947
978.
Małgorzata M. Posmyk Renata Kontek Krystyna M. Janas 《Acta Physiologiae Plantarum》2008,30(4):481-491
Natural phenolic compounds (phenolic acids, flavonoids, tannins, lignans) present in food of plant origin are in the focus
of interest due to their prevalence, properties and biological activity. The aim of the presented work was to investigate
antioxidant and antigenotoxic effects of the anthocyanin-rich extract from red cabbage leaves (Brassica oleracea rubrum) on the changes induced by toxic Cu2+ concentrations. MeOH extract from red cabbage containing anthocyanin (ATH) and phenolic acid derivatives exhibited strong
antioxidant properties. Cu2+ decreased mitotic index (MI) and inhibited proliferative activity of Vicia faba root meristematic cells. The morphology of mitotic chromosomes was changed; “erosion” and pulverization might result from
Cu2+ high-cytotoxicity. Numerous micronuclei, chromatid bridges and lagging/lost chromosomes were found in the meristematic cells
of V. faba, which indicate the clastogenic effect of Cu2+. The application of the ATH-rich extract lowered the number of disturbances induced by Cu2+. The positive role of the ATH-rich red cabbage extract will be discussed. 相似文献
979.
Ozga M Dolot R Janicka M Kaczmarek R Krakowiak A 《The Journal of biological chemistry》2010,285(52):40809-40818
Nucleoside 5′-O-phosphorothioates are formed in vivo as primary products of hydrolysis of oligo(nucleoside phosphorothioate)s (PS-oligos) that are applied as antisense therapeutic molecules. The biodistribution of PS-oligos and their pharmacokinetics have been widely reported, but little is known about their subsequent decay inside the organism. We suggest that the enzyme responsible for nucleoside 5′-O-monophosphorothioate ((d)NMPS) metabolism could be histidine triad nucleotide-binding protein 1 (Hint-1), a phosphoramidase belonging to the histidine triad (HIT) superfamily that is present in all forms of life. An additional, but usually ignored, activity of Hint-1 is its ability to catalyze the conversion of adenosine 5′-O-monophosphorothioate (AMPS) to 5′-O-monophosphate (AMP). By mutagenetic and biochemical studies, we defined the active site of Hint-1 and the kinetic parameters of the desulfuration reaction (P-S bond cleavage). Additionally, crystallographic analysis (resolution from 1.08 to 1.37 Å) of three engineered cysteine mutants showed the high similarity of their structures, which were not very different from the structure of WT Hint-1. Moreover, we found that not only AMPS but also other ribonucleoside and 2′-deoxyribonucleoside phosphorothioates are desulfurated by Hint-1 at the following relative rates: GMPS > AMPS > dGMPS ≥ CMPS > UMPS > dAMPS ≫ dCMPS > TMPS, and during the reaction, hydrogen sulfide, which is thought to be the third gaseous mediator, was released. 相似文献
980.
Danielle Berger Evaldo Toniolo Kubaski Thiago Sequinel Renata Martins da Silva Sergio Mazurek Tebcherani José Arana Varela 《Luminescence》2013,28(6):942-947
ZnO thin films were prepared by the polymeric precursor method. The films were deposited on silicon substrates using the spin‐coating technique, and were annealed at 330 °C for 32 h under pressure‐assisted thermal annealing and under ambient pressure. Their structural and optical properties were characterized, and the phases formed were identified by X‐ray diffraction. No secondary phase was detected. The ZnO thin films were also characterized by field‐emission scanning electron microscopy, Fourier transform infrared spectroscopy, photoluminescence and ultraviolet emission intensity measurements. The effect of pressure on these thin films modifies the active defects that cause the recombination of deep level states located inside the band gap that emit yellow–green (575 nm) and orange (645 nm) photoluminescence. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献