Hepatic gluconeogenesis in rats trained to eat a single meal daily. Role of eating periodicity and the amount of food ingested in the last meal

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biosynthetic origins of the isoprene units of 4-nerolidylcatechol in Potomorphe umbellata

The biosynthetic origins of the isoprene units of 4-nerolidylcatechol (1), the major constituent of Potomorphe umbellata, have been studied through feeding experiments with [14C]- and [13C]-glucose, and with precursors of the mevalonic acid and triose/pyruvate pathways, namely, [2- 14C]-mevalonolactone and [U-14C]-glyceraldehyde-3- phosphate, respectively. The pattern of incorporation of label from [1- 13C]-glucose into 1 was determined by quantitative 13C NMR spectroscopy. The labelling pattern revealed that the additive was specifically incorporated, and that the isoprene units of the sesquiterpenoid moiety of 4-nerolidylcatechol were derived from both the mevalonic acid and the triose/pyruvate pathways. The results indicate that both plastidic and cytoplasmic pathways are able to provide isopentenyl diphosphate units for the biosynthesis of 1. ©2005 Sociedade Brasileira de Química.

Biosynthetic origin of the isoprene units in chromenes of Piper aduncum (Piperaceae)

Metabolic studies involving the incorporation of [1-13C]-D- glucose into intact leaves of Piper aduncum (Piperaceae) have indicated that both the mevalonate (MVA) and the pyruvate-triose (MEP) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8- (3′-methyl-2′-butenyl)-2H-1-chromene-6-carboxylate (2). The pattern of incorporation of label from [1-13C]-D-glucose into these chromenes was determined by quantitative 13C NMR spectroscopy. The results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/ or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space. ©2007 Sociedade Brasileira de Química.

Autoimmunity does not contribute to the highly prevalent glucose metabolism disturbances in a Japanese Brazilian population

The Japanese Brazilian population has one of the highest prevalences of diabetes worldwide. Despite being non-obese according to standard definitions, their body fat distribution is typically central. We investigated whether a subset of these subjects had autoantibodies that would suggest a slowly progressive form of type 1 diabetes. A total of 721 Japanese Brazilians (386 men) in the 30- to 60-year age group underwent clinical examination and laboratory procedures, including a 75-g oral glucose tolerance test and determinations of serum autoantibodies. Antibodies to glutamic acid decarboxylase (GADab) were determined by radioimmunoassay and to thyroglobulin (TGab) and thyroperoxidase (TPOab) by flow-cytometry assays. Mean body mass index was 25.2 ± 3.8 kg/m2, but waist circumference was elevated according to the Asian standards. Diabetes, impaired glucose tolerance, and impaired fasting glycemia were found in 31%, 22%, and 22%, respectively, and 53% of the subjects had metabolic syndrome. Glutamic acid decarboxylase (GADab) was positive in 4.72%, TGab in 9.6%, and TPOab in 10% of the whole sample. When participants were stratified according to the presence of thyroid antibodies, similar frequencies of GADab were found in positive and negative groups. The prevalence rates of glucose metabolism disturbances did not differ between GADab positive and negative groups. Our data did not support the view that autoimmune injury could contribute to the high prevalence of diabetes seen in Japanese Brazilians, and the presence of co-morbidities included in the spectrum of metabolic syndrome favors the classification as type 2 diabetes.

Production and partial characterization of keratinase produced by a microorganism isolated from poultry processing plant wastewater

A Streptomyces was isolated from poultry plant wastewater, showed high keratinolytic activity when cultured on feather meal medium. Optimum keratinolytic activity was observed at 40°C and pH 8.0. The enzyme also showed to be stable between 40 and 60°C. The keratinolytic activity was not inhibited by EDTA, DMSO and Tween 80. On the other hand, CaCl2, ZnCl2, and BaCl2 slightly inhibited the keratinolytic activity. The Streptomyces isolated might be useful in leather, keratin waste treatment, animal feeding industry, and also cosmetic industry. © 2008 Academic Journals.

Infantile epileptic encephalopathy with hypsarrhythmia (infantile spasms/west syndrome) and immunity

West syndrome is a severe epilepsy, occurring in infancy, that comprises epileptic seizures known as spasms, in clusters, and a unique EEG pattern, hypsarrhythmia, with psychomotor regression. Maturation of the brain is a crucial component. The onset is within the first year of life, before 12 months of age. Patients are classified as cryptogenic (10 to 20%), when there are no known or diagnosed previous cerebral insults, and symptomatic (80 to 90%), when associated with pre-existing cerebral damages. The time interval from a brain insult to infantile spasms onset ranged from 6 weeks to 11 months. West syndrome has a time-limited natural evolutive course, usually disappearing by 3 or 4 years of age. In 62% of patients, there are transitions to another age-related epileptic encephalopathies, the Lennox-Gastaut Syndrome and severe epilepsy with multiple independent foci. Spontaneous remission and remission after viral infections may occur. Therapy with ACTH and corticosteroids are the most effective. Reports about intravenous immunoglobulins action deserve attention. There is also immune dysfunction, characterized mainly by anergy, impaired cell-mediated immunity, presence of immature thymocytes in peripheral blood, functional impairment of T lymphocytes induced by plasma inhibitory factors, and altered levels of immunoglobulins. Changes in B lymphocytes frequencies and increased levels of activated B cells have been reported. Sensitized lymphocytes to brain extract were also described. Infectious diseases are frequent and may, sometimes, cause fatal outcomes. Increase of pro-inflamatory cytokines in serum and cerebrospinal fluid of epileptic patients were reported. Association with specific HLA antigens was described by several authors (HLA-DR7, HLA-A7, HLA-DRw52, and HLA-DR5). Auto-antibodies to brain antigens, of several natures (N-methyl-d-aspartate glutamate receptor, gangliosides, brain tissue extract, synaptic membrane, and others), were described in epileptic patients and in epileptic syndromes. Experimental epilepsy studies with anti-brain antibodies demonstrated that epileptiform discharges can be obtained, producing hyperexcitability leading to epilepsy. We speculate that in genetically prone individuals, previous cerebral lesions may sensitize immune system and trigger an autoimmune disease. Antibody to brain antigens may be responsible for impairment of T cell function, due to plasma inhibitory effect and also cause epilepsy in immature brains. © 2008 Bentham Science Publishers Ltd.

Glucocorticoids in vivo induce both insulin hypersecretion and enhanced glucose sensitivity of stimulus-secretion coupling in isolated rat islets

Although glucocorticoids are widely used as antiinflammatory agents in clinical therapies, they may cause serious side effects that include insulin resistance and hyperinsulinemia. To study the potential functional adaptations of the islet of Langerhans to in vivo glucocorticoid treatment, adult Wistar rats received dexamethasone (DEX) for 5 consecutive days, whereas controls (CTL) received only saline. The analysis of insulin release in freshly isolated islets showed an enhanced secretion in response to glucose in DEX-treated rats. The study of Ca2 2+ signals by fluorescence microscopy also demonstrated a higher response to glucose in islets from DEX-treated animals. However, no differences in Ca2 2+signals were found between both groups with tolbutamide or KCl, indicating that the alterations were probably related to metabolism. Thus, mitochondrial function was explored by monitoring oxidation of nicotinamide dinucleotide phosphate autofluorescence and mitochondrial membrane potential. Both parameters revealed a higher response to glucose in islets from DEX-treated rats. The mRNA and protein content of glucose transporter-2, glucokinase, and pyruvate kinase was similar in both groups, indicating that changes in these proteins were probably not involved in the increased mitochondrial function. Additionally,weexplored the status of Ca2 2+-dependent signaling kinases. Unlike calmodulin kinase II, we found an augmented phosphorylation level of protein kinase Cα as well as an increased response of the phospholipase C/inositol 1,4,5-triphosphate pathway in DEX-treated rats. Finally, an increased number of docked secretory granules were observed in the β-cells of DEX animals using transmission electron microscopy. Thus, these results demonstrate that islets from glucocorticoid-treated rats develop several adaptations that lead to an enhanced stimulus-secretion coupling and secretory capacity. Copyright © 2010 by The Endocrine Society.

Thiamin Requirement of Nile Tilapia, Oreochromis niloticus

Juvenile Nile tilapia, Oreochromis niloticus, were fed to apparent satiation twice daily with purified diets containing 0, 1.0, 2.0, 4.0, 8.0, and 16.0 mg/kg and 0, 2.0, 4.0, 8.0, 16.0, and 32.0 mg/kg of thiamin in separate 14- and 8-wk trials (Experiments 1 and 2, respectively). Fish fed the diet devoid of thiamin developed neurological disorders, anorexia, reduced growth, and feed efficiency and increased mortality (Experiment 2 only) within 4-6 and 8-10 wk for Experiments 2 and 1, respectively. Low red blood cell count (RBC) and hematocrit (Ht) were observed in fish fed the thiamin-deficient diet. Serum pyruvate was elevated in fish fed the thiamin unsupplemented diet. Serum lactate was not affected by dietary thiamin levels. Whole body protein was unaffected by dietary levels of thiamin. Body moisture and ash increased whereas body lipid decreased in fish fed the thiamin unsupplemented diets. None of these abnormalities were observed in fish fed the thiamin-supplemented diets. Using the response curves determined by PROC NLMIXED to estimate dietary thiamin levels required for various response variables, a dietary thiamin level of 3.5 mg/kg diet was adequate for optimum growth, feed intake and efficiency, survival, prevention of neurological symptoms, and maintaining normal levels of RBC, Ht, serum pyruvate, and proximate body composition. © 2011.

Low dose of dichloroacetate infusion reduces blood lactate after submaximal exercise in horses

The acute administration of an indirect activator of the enzyme pyruvate dehydroge-nase (PDH) in human athletes causes a reduction in blood lactate level during and after exercise. A single IV dose (2.5m.kg-1) of dichloroacetate (DCA) was administered before a submaximal incremental exercise test (IET) with five velocity steps, from 5.0 m.s-1 for 1 min to 6.0, 6.5, 7.0 and 7.5m.s-1 every 30s in four untrained mares. The blood collections were done in the period after exercise, at times 1, 3, 5, 10, 15 and 20 min. Blood lactate and glucose (mM) were determined electro-enzymatically utilizing a YSI 2300 automated analyzer. There was a 15.3% decrease in mean total blood lactate determined from the values obtained at all assessment times in both trials after the exercise. There was a decrease in blood lactate 1, 3, 5, 10, 15 and 20 min after exercise for the mares that received prior DCA treatment, with respective mean values of 6.31±0.90 vs 5.81±0.50, 6.45±1.19 vs 5.58±1.06, 6.07±1.56 vs 5.26±1.12, 4.88±1.61 vs 3.95±1.00, 3.66±1.41 vs 2.86±0.75 and 2.75±0.51 vs 2.04±0.30. There was no difference in glucose concentrations. By means of linear regression analysis, V140, V160, V180 and V200 were determined (velocity at which the rate heart is 140, 160, 180, and 200 beats/minute, respectively). The velocities related to heart rate did not differ, indicating that there was no ergogenic effect, but prior administration of a relatively low dose of DCA in mares reduced lactatemia after an IET.

Combined effects of age and diet-induced obesity on biochemical parameters and cardiac energy metabolism in rats

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

Caracterização estrutural de polissacarídeos produzidos por bactérias dos gêneros Rhizobium e Mesorhizobium

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo de parâmetros de fermentação na produção de biopolímeros por bactérias isoladas do solo e caracterização química dos grupamentos acetila e piruvato nos biopolímeros obtidos

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Influência da oxidação de glicose sobre a função miocárdica de ratos obesos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo de isoenzimas de metabolismo de carboidratos e clonagem e expressão da enolase de Xylella fastidiosa

Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

Maturação in vitro de oócitos ovinos com o uso da roscovitina e ciclohexemida

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