Antibacterial properties of propolis and products containing propolis from Brazil

Crude propolis and commercial products containing propolis, such as ethanolic extracts, tablets, capsules and powders acquired in São Paulo City (Brazil) were analyzed. The resins of the solid products were extracted with ethanol and found to be present at various concentrations, independently of the propolis concentration specified on the label of the commercial products. The in vitro activity of these resins against S aureus, B cereus and B subrilis was also determined. The results showed that the antibacterial activity rather than the propolis concentration itself should be considered for quality control and that some resins are likely to display a species-specific action.

Efeitos da interação e toxicidade das proteínas Cry1 e Vip3Aa de Bacillus thuringiensis, Berliner em Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

Pós-graduação em Microbiologia Agropecuária - FCAV

Antineoplásico potencial: síntese de derivado de salicilato de octila e5-fluoruracila para tratamento do câncer de pele

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Perfil de expressão e organização genômica de micrornas músculo-específicos na tilápia-do-nilo (Oreochromis nicoticus)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Meal size and specific dynamic action in the rattlesnake Crotalus durissus (Serpentes : Viperidae)

We studied the effect of meal size on specific dynamic action (SDA) in the South American rattlesnake Crotalus durissus, by measuring oxygen consumption rates (VO2) prior to and after the ingestion of meals ranging from 10-50% of snake's body mass. Regardless of meal size, variation in VO2 with time during digestion demonstrated the same general pattern. Oxygen consumption rates peaked between 15 and 33 h post-feeding, at values 3.7-7.3 times those prior to feeding. Snakes, while digesting meals of 30% and 50% of their body mass, experienced VO2 that exceeded rates measured during forced activity. Following peaks in VO2, rates returned to prefeeding values within 62-170 h post-feeding. Post-prandial peak in VO2 and the duration of the metabolic response to feeding increased with meal size. Digestion is an energetically demanding activity for C. durissus, with an estimated cost equaling 12-18% of the ingested assimilated energy.

Protein deficiency and nutritional recovery modulate insulin secretion and the early steps of insulin action in rats

Maternal malnutrition was shown to affect early growth and leads to permanent alterations in insulin secretion and sensitivity of offspring. In addition, epidemiological studies showed an association between low birth weight and glucose intolerance in adult life. To understand these interactions better, we investigated the insulin secretion by isolated islets and the early events related to insulin action in the hind-limb muscle of adult rats fed a diet of 17% protein (control) or 6% protein [low (LP) protein] during fetal life, suckling and after weaning, and in rats receiving 6% protein during fetal life and suckling followed by a 17% protein diet after weaning (recovered). The basal and maximal insulin secretion by islets from rats fed LP diet and the basal release by islets from recovered rats were significantly lower than that of control rats. The dose-response curves to glucose of islets from LP and recovered groups were shifted to the right compared to control islets, with the half-maximal response (EC 50) occurring at 16.9 ± 1.3, 12.4 ± 0.5 and 8.4 ± 0.1 mmol/L, respectively. The levels of insulin receptor, as well as insulin receptor substrate-1 and phosphorylation and the association between insulin receptor substrate-1 and phosphatidylinositol 3-kinase were greater in rats fed a LP diet than in control rats. In recovered rats, these variables were not significantly different from those of the other two groups. These results suggest that glucose homeostasis is maintained in LP and recovered rats by an increased sensitivity to insulin as a result of alterations in the early steps of the insulin signal transduction pathway.

Ablation of the ability to control the right-to-left cardiac shunt does not affect oxygen uptake, specific dynamic action or growth in the rattlesnake Crotalus durissus

The morphologically undivided ventricle of the heart in non-crocodilian reptiles permits the mixing of oxygen-rich blood returning from the lungs and oxygen-poor blood from the systemic circulation. A possible functional significance for this intra-cardiac shunt has been debated for almost a century. Unilateral left vagotomy rendered the single effective pulmonary artery of the South American rattlesnake, Crotalus durissus, unable to adjust the magnitude of blood flow to the lung. The higher constant perfusion of the lung circulation and the incapability of adjusting the right-left shunt in left-denervated snakes persisted over time, providing a unique model for investigation of the long-term consequences of cardiac shunting in a squamate. Oxygen uptake recorded at rest and during spontaneous and forced activity was not affected by removing control of the cardiac shunt. Furthermore, metabolic rate and energetic balance during the post-prandial metabolic increment, plus the food conversion efficiency and growth rate, were all similarly unaffected. These results show that control of cardiac shunting is not associated with a clear functional advantage in adjusting metabolic rate, effectiveness of digestion or growth rates. © 2013. Published by The Company of Biologists Ltd.

Temperature and thermal regime effects on the specific dynamic action of Bothrops alternatus (Serpentes, Viperidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biochemical and biological evaluation of gyroxin isolated from Crotalus durissus terrificus venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic polymorphisms associated with steroids metabolism and insulin action in polycystic ovary syndrome

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Transcriptional Profile of Diuron-Induced Toxicity on the Urinary Bladder of Male Wistar Rats to Inform Mode of Action

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Propolis Immunomodulatory Action In Vivo on Toll-Like Receptors 2 and 4 Expression and on Pro-Inflammatory Cytokines Production in Mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endurance training improves responsiveness to insulin and modulates insulin signal transduction through the phosphatidylinositol 3-kinase/Akt-1 pathway

Background: Endurance training increases insulin-stimulated muscle glucose transport and leads to improved metabolic control in diabetic patients.Objective: To analyze the effects of endurance training on the early steps of insulin action in muscle of rats. Design: Male rats submitted to daily swimming for 6 weeks were compared with sedentary controls. At the end of the training period, anesthetized animals received an intravenous (i.v.) injection of insulin and had a fragment of their gastrocnemius muscle excised for the experiments.Methods: Associations between insulin receptor, insulin receptor substrates (IRS)-1 and -2 and phosphatidylinositol 3-kinase (PI3-kinase) were analyzed by immunoprecipitation and immunoblotting. Akt-1 serine phosphorylation and specific protein quantification were detected by immunoblotting of total extracts, and IRS-1/IRS-2-associated PI3-kinase activity were determined by thin-layer chromatography.Results: Insulin-induced phosphorylation of IRS-1 and IRS-2 increased respectively by 1.8-fold (P < 0.05) and 1.5-fold (P < 0.05), whereas their association with PI3-kinase increased by 2.3-fold (P < 0.05) and 1.9-fold (P < 0.05) in trained rats as compared with sedentary controls, respectively. The activity of PI3-kinase associated with IRS-1 and IRS-2 increased by 1.8-fold (P < 0.05) and 1.7-fold (P < 0.05) respectively, in trained rats as compared with their untrained counterparts. Serine phosphorylation of Akt-1/PKB increased 1.7-fold (P < 0.05) in trained rats in response to insulin. These findings were accompanied by increased responsiveness to insulin as demonstrated by a reduced area under the curve for insulin during an i.v. glucose tolerance test, by increased glucose disappearance rate during an insulin tolerance test, and by increased expression of glucose transporter-4.Conclusions: the increased responsiveness to insulin induced by chronic exercise in rat skeletal muscle may result, at least in part, from the modulation of the insulin signaling pathway at different molecular levels.

UMP kinase from Mycobacterium tuberculosis: Mode of action and allosteric interactions, and their likely role in pyrimidine metabolism regulation

The pyrH-encoded uridine 5′-monophosphate kinase (UMPK) is involved in both de novo and salvage synthesis of DNA and RNA precursors. Here we describe Mycobacterium tuberculosis UMPK (MtUMPK) cloning and expression in Escherichia coli. N-terminal amino acid sequencing and electrospray ionization mass spectrometry analyses confirmed the identity of homogeneous MtUMPK. MtUMPK catalyzed the phosphorylation of UMP to UDP, using ATP-Mg 2+ as phosphate donor. Size exclusion chromatography showed that the protein is a homotetramer. Kinetic studies revealed that MtUMPK exhibits cooperative kinetics towards ATP and undergoes allosteric regulation. GTP and UTP are, respectively, positive and negative effectors, maintaining the balance of purine versus pyrimidine synthesis. Initial velocity studies and substrate(s) binding measured by isothermal titration calorimetry suggested that catalysis proceeds by a sequential ordered mechanism, in which ATP binds first followed by UMP binding, and release of products is random. As MtUMPK does not resemble its eukaryotic counterparts, specific inhibitors could be designed to be tested as antitubercular agents. © 2010 Elsevier Inc. All rights reserved.

A rescaling of the phase space for Hamiltonian map: Applications on the Kepler map and mappings with diverging angles in the limit of vanishing action

A rescale of the phase space for a family of two-dimensional, nonlinear Hamiltonian mappings was made by using the location of the first invariant Kolmogorov-Arnold-Moser (KAM) curve. Average properties of the phase space are shown to be scaling invariant and with different scaling times. Specific values of the control parameters are used to recover the Kepler map and the mapping that describes a particle in a wave packet for the relativistic motion. The phase space observed shows a large chaotic sea surrounding periodic islands and limited by a set of invariant KAM curves whose position of the first of them depends on the control parameters. The transition from local to global chaos is used to estimate the position of the first invariant KAM curve, leading us to confirm that the chaotic sea is scaling invariant. The different scaling times are shown to be dependent on the initial conditions. The universality classes for the Kepler map and mappings with diverging angles in the limit of vanishing action are defined. © 2013 Published by Elsevier Inc. All rights reserved.