182 research outputs found

    Acute low-intensity cycling with blood-flow restriction has no effect on metabolic signaling in human skeletal muscle compared to traditional exercise

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    Purpose Autophagy is an intracellular degradative system sensitive to hypoxia and exercise-induced perturbations to cellular bioenergetics. We determined the effects of low-intensity endurance-based exercise performed with blood-flow restriction (BFR) on cell signaling adaptive responses regulating autophagy and substrate metabolism in human skeletal muscle. Methods In a randomized cross-over design, nine young, healthy but physically inactive males completed three experimental trials separated by 1 week of recovery consisting of either a resistance exercise bout (REX: 4 × 10 leg press repetitions, 70% 1-RM), endurance exercise (END: 30 min cycling, 70% VO2peak), or low-intensity cycling with BFR (15 min, 40% VO2peak). A resting muscle biopsy was obtained from the vastus lateralis 2 weeks prior to the first exercise trial and 3 h after each exercise bout. Results END increased ULK1Ser757 phosphorylation above rest and BFR (~37 to 51%, P < 0.05). Following REX, there were significant elevations compared to rest (~348%) and BFR (~973%) for p38γ MAPKThr180/Tyr182 phosphorylation (P < 0.05). Parkin content was lower following BFR cycling compared to REX (~20%, P < 0.05). There were no exercise-induced changes in select markers of autophagy following BFR. Genes implicated in substrate metabolism (HK2 and PDK4) were increased above rest (~143 to 338%) and BFR cycling (~212 to 517%) with END (P < 0.001). Conclusion A single bout of low-intensity cycling with BFR is insufficient to induce intracellular “stress” responses (e.g., high rates of substrate turnover and local hypoxia) necessary to activate skeletal muscle autophagy signaling

    Desenhos de estruturas químicas correlacionam-se com propriedades biológicas: MIA-QSAR

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    Descriptors in multivariate image analysis applied to quantitative structure-activity relationship (MIA-QSAR) are pixels of bidimensional images of chemical structures (drawings), which were used to model the trichomonicidal activities of a series of benzimidazole derivatives. The MIA-QSAR model showed good predictive ability, with r², q² and r val. ext.² of 0.853, 0.519 and 0.778, respectively, which are comparable to the best values obtained by CoMFA e CoMSIA for the same series. A MIA-based analysis was also performed by using images of alphabetic letters with the corresponding numeric ordering as dependent variables, but no correlation was found, supporting that MIA-QSAR is not arbitrary

    Can Euseius alatus DeLeon (Acari: Phytoseiidae) prey on Aceria guerreronis Keifer (Acari: Eriophyidae) in coconut palm?

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    Ácaros do gênero Euseius são geralmente considerados especialistas na alimentação de pólen. Euseius alatus DeLeon é uma das seis espécies de ácaros fitoseídeos mais comumente encontrados em plantas de coqueiro no Nordeste do Brasil, associado com Aceria guerreronis Keifer. Apesar de a morfologia de E. alatus não favorecer a exploração da área meristemática do fruto habitada por A. guerreronis, o predador pode ter algum papel no controle do eriofídeo durante o processo de dispersão. O objetivo deste trabalho foi avaliar o desenvolvimento e a reprodução de E. alatus nas seguintes dietas: A. guerreronis, pólen de Ricinus communis (Euphorbiaceae); e Tetranychus urticae Koch (Tetranychidae) + pólen de R. communis + mel a 10 %. Euseius alatus desenvolveu-se mais rapidamente e ovipositou mais quando alimentada em dieta composta por T. urticae + pólen + mel. Contudo, os parâmetros da tabela de vida foram muito semelhantes em todas as dietas, sugerindo que E. alatus pode contribuir na redução da população de A. guerreronis no campo.Mites of the genus Euseius are generally considered specialist as pollen feeders. Euseius alatus DeLeon is one of the six species of phytoseiid mites most commonly found on coconut plants in northeast Brazil associated with Aceria guerreronis Keifer. Although the morphology of E. alatus does not favor the exploitation of the meristematic area of the fruit inhabited by A. guerreronis, the predator may have some role in the control of this eriophyid during the dispersion process. The objective of this work was to evaluate the development and reproduction of E. alatus on the following diets: A. guerreronis, Ricinus communis pollen (Euphorbiaceae), and Tetranychus urticae Koch (Tetranychidae) + R. communis pollen + honey solution 10%. Euseius alatus developed slightly faster and had slightly higher oviposition rate when feeding on the diet composed of T. urticae + pollen + honey. However, life table parameters were very similar on all diets, suggesting that E. alatus may contribute in reducing the population of A. guerreronis in the field.CNPqUniversidade Federal Rural de Pernambuc

    Copper(ii) Nitroaromatic Schiff Base Complexes: Synthesis, Biological Activity And Their Interaction With Dna And Albumins

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Copper(II) complexes of the Schiff base ligands 2-((5-nitrofuran-2-yl)methyleneamino)phenol (HL1) and 2-(4-nitrobenzylideneamino)phenol (HL2) were prepared and characterized using physicochemical and spectroscopic techniques. In these complexes the Schiff base ligands acted as a bidentate donor bound to Cu2+ through the oxygen and nitrogen atoms in the deprotonated form. The electron paramagnetic resonance spectra, carried out on [CuCl(L1)(phen)]center dot 0.5H(2)O and [CuCl(L2)(phen)]center dot 2H(2)O complexes, showed the presence of only mononuclear forms. The Cu2+ complexes and ligands were evaluated for their in vitro trypanocidal activity. The complex [CuCl(L1)(phen)]center dot 0.5H(2)O was more active than the free Schiff base and also presented a superior effect to benznidazole, the reference drug. The antiproliferative activity of the Schiff bases and Cu2+ complexes were evaluated for their effect on seven tumor cell lines and showed a cytostatic and in some cases a cytotoxic effect. These compounds also presented binding properties to deoxyribonucleic acid (DNA) and moderate ability to quench the intrinsic fluorescence of albumins.2818797Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)FIOCRUZConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Schiff bases: A short review of their antimicrobial activities

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    AbstractSchiff bases are aldehyde- or ketone-like compounds in which the carbonyl group is replaced by an imine or azomethine group. They are widely used for industrial purposes and also exhibit a broad range of biological activities. This short review compiles examples of the most promising antimalarial, antibacterial, antifungal, and antiviral Schiff bases. An overview of synthetic methodologies used for the preparation of Schiff bases is also described

    Enzymatic synthesis of sugar esters and their potential as surface-active stabilizers of coconut milk emulsions

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    Sugar esters are compounds with surfactant properties (biosurfactants), i.e., capable of reducing the surface tension and promote the emulsification of immiscible liquids. On the other hand, as with all emulsions, coconut milk is not physically stable and is prone to phase separation. Therefore, the aim of this work was to evaluate the synthesis of fructose, sucrose and lactose esters from the corresponding sugars using Candida antarctica type B lipase immobilized in two different supports, namely acrylic resin and chitosan, and evaluate its application in the stabilization of coconut milk emulsions. The enzyme immobilized on chitosan showed the highest yield of lactose ester production (84.1%). Additionally, the production of fructose ester was found to be higher for the enzyme immobilized on the acrylic resin support (74.3%) as compared with the one immobilized on chitosan (70.1%). The same trend was observed for the sucrose ester, although with lower percentage yields. Sugar esters were then added to samples of fresh coconut milk and characterized according to their surface tension, emulsification index and particle size distribution. Although the microscopic analysis showed similar results for all sugar esters, results indicated lactose ester as the best biosurfactant, with a surface tension of 38.0 N/m and an emulsification index of 54.1%, when used in a ratio of 1:10 (biosurfactant: coconut milk, v/v) for 48 hour experiments.The authors acknowledge the AlBan Programme (European Union Programme of High Level Scholarships for Latin America) for financial support of N. Lopes through the research grant E07D401544BR. Furthermore, the authors acknowledge the Chemical Engineering Department e Federal University of Ceara (Campus of Pici - Brazil) and Biotechnology Laboratory - Federal University of Ceara for enabling the use of their laboratory facilities

    Attenuated PGC-1 alpha Isoforms following Endurance Exercise with Blood Flow Restriction

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    Introduction: Exercise performed with blood flow restriction simultaneously enhances the acute responses to both myogenic and mitochondrial pathways with roles in training adaptation. We investigated isoform-specific gene expression of the peroxisome proliferator-activated receptor gamma (PPARG) coactivator 1 and selected target genes and proteins regulating skeletal muscle training adaptation. Methods: 9 healthy, untrained males participated in a randomized, counter-balanced, cross-over design in which each subject completed a bout of low-intensity endurance exercise performed with blood flow restriction (15 min cycling at 40% of VO2peak, BFR-EE), endurance exercise (30 min cycling at 70% of VO2peak, EE) or resistance exercise (4 x 10 repetitions of leg press at 70% of 1-repetition maximum, RE) separated by at least one week recovery. A single resting muscle biopsy (vastus lateralis) was obtained two weeks before the first exercise trial (rest) and 3 h after each boat. Results: Total PGC-1α mRNA abundance, along with all four isoforms, increased above rest with EE only (P<0.05) being higher than BFR-EE (P<0.05). PGC-1α1, 2 and 4 were higher after EE compared to RE (P<0.05). EE also increased VEGF, Hif-1α and MuRF-1 mRNA abundance above rest (P<0.05) while COXIV mRNA expression increased with EE compared to BFR-EE (P<0.05). Conclusion: The attenuated expression of all four PGC- 1α isoforms when endurance exercise is performed with blood flow restriction suggests this type of exercise provides an insufficient stimulus to activate the signaling pathways governing mitochondrial and angiogenesis responses observed with moderate- to high intensity endurance exercise

    Effect of chronic treatment with Rosiglitazone on Leydig cell steroidogenesis in rats: In vivo and ex vivo studies

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    <p>Abstract</p> <p>Background</p> <p>The present study was designed to examine the effect of chronic treatment with rosiglitazone - thiazolidinedione used in the treatment of type 2 diabetes mellitus for its insulin sensitizing effects - on the Leydig cell steroidogenic capacity and expression of the steroidogenic acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc) in normal adult rats.</p> <p>Methods</p> <p>Twelve adult male Wistar rats were treated with rosiglitazone (5 mg/kg) administered by gavage for 15 days. Twelve control animals were treated with the vehicle. The ability of rosiglitazone to directly affect the production of testosterone by Leydig cells <it>ex vivo </it>was evaluated using isolated Leydig cells from rosiglitazone-treated rats. Testosterone production was induced either by activators of the cAMP/PKA pathway (hCG and dbcAMP) or substrates of steroidogenesis [22(R)-hydroxy-cholesterol (22(R)-OH-C), which is a substrate for the P450scc enzyme, and pregnenolone, which is the product of the P450scc-catalyzed step]. Testosterone in plasma and in incubation medium was measured by radioimmunoassay. The StAR and P450scc expression was detected by immunocytochemistry.</p> <p>Results</p> <p>The levels of total circulating testosterone were not altered by rosiglitazone treatment. A decrease in basal or induced testosterone production occurred in the Leydig cells of rosiglitazone-treated rats. The ultrastructural and immunocytochemical analysis of Leydig cells from rosiglitazone-treated rats revealed cells with characteristics of increased activity as well as increased StAR and P450scc expression, which are key proteins in androgen biosynthesis. However, a number of rosiglitazone-treated cells exhibited significant mitochondrial damage.</p> <p>Conclusion</p> <p>The results revealed that the Leydig cells from rosiglitazone-treated rats showed significant reduction in testosterone production under basal, hCG/dbcAMP- or 22 (R)-OH-C/pregnenolone-induced conditions, although increased labeling of StAR and P450scc was detected in these cells by immunocytochemistry. The ultrastructural study suggested that the lower levels of testosterone produced by these cells could be due to mitochondrial damage induced by rosiglitazone.</p

    1H low- and high-field NMR study of the effects of plasma treatment on the oil and water fractions in crude heavy oil

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    AbstractThe chemical and physical properties of a Brazilian heavy oil submitted to plasma treatment were investigated by 1H low- and high-field nuclear magnetic resonance (NMR) combined to the characterization of rheological properties, thermogravimetry and measurement of basic sediments and water (BSW) content. The crude oil was treated in a dielectric barrier discharge plasma reactor, using natural gas, CO2 or H2 as working gas. The results indicated a large drop in the water content of the plasma-treated samples as compared to the crude oil, giving rise to a reduction in the viscosity. No significant chemical change was produced in the oil portion itself, as observed by 1H NMR. The water contents determined by 1H low-field NMR analyses agreed well with those obtained by BSW, indicating the low-field NMR methods as a useful tool for following the effects of plasma treatments on heavy oils, allowing the separation of the effects caused on the water and oil fractions
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