Efeito da intensidade do exercício sobre a oxidação de carboidratos e gorduras durante a recuperação pós-exercício em diabéticos tipo 2 / Effects of exercise intensity in fat and carbohydrate oxidation during post-exercise recovery in type 2 diabetes

Indivíduos com diabetes tipo 2 apresentam alterações na utilização de substratos energéticos em repouso e durante o exercício, como capacidade reduzida de utilização de carboidratos e síntese de glicogênio muscular, acentuando a hiperglicemia e a resistência à insulina. Estudos têm demonstrado que o exercício pode ser efetivo no controle e tratamento do diabetes tipo 2, porém o efeito de diferentes intensidades de exercício sobre a contribuição de carboidratos e gorduras durante a recuperação ainda não foi elucidado. Participaram do estudo 20 indivíduos sedentários, divididos em 2 grupos, sendo 9 diabéticos tipo 2 (DB) (2 mulheres) e 11 não diabéticos (ND) (2 mulheres), os quais foram submetidos a 3 sessões experimentais: Teste incremental máximo (TI), seguido de sessão de exercício submáximo realizado a 90% da carga do limiar de lactato (90%LL) e sessão controle (C) sem a realização de exercício, estas duas últimas em ordem randomizada. Em todas as sessões experimentais, os participantes permaneceram em repouso durante 20 min antes do inicio das sessões, bem como por 135 minutos durante o período de recuperação pós-exercício ou controle para a mensuração das variáveis ventilatórias, sendo que aos 45 minutos de recuperação uma solução de carboidrato (CHO) foi administrada. Ambos os grupos apresentaram elevada oxidação de carboidratos durante as sessões de exercício máximo (TI) e submáximo (90%LL) quando comparado aos valores de repouso (p<0,05). A oxidação de gorduras ficou elevada durante o período de recuperação do TI em ambos os grupos (p<0,05), contudo, no grupo DB, essa alteração se prolongou por um maior período de recuperação. Por outro lado, durante a recuperação do exercício submáximo, somente o grupo ND apresentou oxidação de gordura elevada após 60 min de recuperação...

Individuals with type 2 diabetes (DB) have changes in energy substrate utilization at rest and during exercise, with less use of carbohydrate and muscle glycogen synthesis, emphasizing the hyperglycemia and insulin resistance. Exercise can help control and treatment of type 2 diabetes, but effect of different exercise intensities on the carbohydrates and fats contribution during recovery has not yet been elucidated. Participated in the study 20 sedentary individuals, 9 individuals (2 women) with type 2 diabetes (DB) and 11 (2 women) without diabetes (ND), underwent three experimental sessions (SE): maximal incremental test (IT); submaximal exercise, 90% of the load of the lactate threshold (90% LL) and control (Cont) or without exercise (the latter two session in randomized order). In all the SE, the participants were at rest (pre-exercise) for 20 minutes and 135 minutes during the post-exercise for measurement of ventilatory variables, and the 45-minute of recovery the volunteers were given a carbohydrate solution was given. The results showed that both groups had high carbohydrate oxidation during exercise of high and moderate intensity compared with rest (p <0.05). The fat oxidation was higher during the recovery of IT in both groups (p <0.05), and longer in the DB. On the other hand, during recovery from moderate exercise, only ND had higher fat oxidation after 60 min of recovery...

Characterization of the interdependency between residues that bind the substrate in a â-glycosidase

The manner by which effects of simultaneous mutations combine to change enzymatic activity is not easily predictable because these effects are not always additive in a linear manner. Hence, the characterization of the effects of simultaneous mutations of amino acid residues that bind the substrate can make a significant contribution to the understanding of the substrate specificity of enzymes. In the â-glycosidase from Spodoptera frugiperda (Sfâgly), both residues Q39 and E451 interact with the substrate and this is essential for defining substrate specificity. Double mutants of Sfâgly (A451E39, S451E39 and S451N39) were prepared by site-directed mutagenesis, expressed in bacteria and purified using affinity chromatography. These enzymes were characterized using p-nitrophenyl â-galactoside and p-nitrophenyl â-fucoside as substrates. The k cat/Km ratio for single and double mutants of Sfâgly containing site-directed mutations at positions Q39 and E451 was used to demonstrate that the effect on the free energy of ES‡ (enzyme-transition state complex) of the double mutations (∆∆G‡xy) is not the sum of the effects resulting from the single mutations (∆∆G‡x and ∆∆G‡y). This difference in ∆∆G‡ indicates that the effects of the single mutations partially overlap. Hence, this common effect counts only once in ∆∆G‡xy. Crystallographic data on â-glycosidases reveal the presence of a bidentate hydrogen bond involving residues Q39 and E451 and the same hydroxyl group of the substrate. Therefore, both thermodynamic and crystallographic data suggest that residues Q39 and E451 exert a mutual influence on their respective interactions with the substrate.

Studies on the anti bacterial and HPFC activity of a phenyl propanoid glycoside

Trans - p -methoxy cinnamic acid is a primary metabolite of Shikimate pathway while acteoside is a natural product of Syringa vulgaris. Both compounds have shown various pharmacological activities. In present paper antimicrobial effect of acteoside and trans - p - methoxy Cinnamic acid was studied and effect on haemolytic plaque forming cells [HPFC] was also evaluated. Significant results were obtained concerning antibacterial activity of trans - p - methoxy cinnamic acid

Alpha-galactoside-binding isolectins from wild jack fruit seed (Artocarpus hirsuta): purification and properties.

Five isolectins with marked specificity for alpha-linked galactose were purified from the wild jack (Artocarpus hirsuta) seeds by affinity chromatography on cross-linked guar gum. They were composed of a glycosylated subunit A (Mr = 16 kDa) and a nonglycosylated subunit B (Mr = 11 kDa) in noncovalent association. The isolectins which eluted as a single peak of Mr 45 kDa on gel filtration in Biogel P-100 and in a TSK G-3000 SW high pressure column, were resolved into five peaks on electrophoresis at pH 4.5. Sodium dodecyl sulphate polyacrylamide gel electrophoreogram of the major isolectin band suggested that the isolectins may be the five possible tetrameric combinations of A and B subunits. The combined isolectins bound only two molecules of 4-methyl umbelliferyl alpha-D-galactoside with a binding constant of 4.75 x 10(4) M-1. The pH optimum of sugar binding was 7.0. The isolectins specifically bound to human IgG and IgA but not to IgM.