Long-term intermittent feeding, but not caloric restriction, leads to redox imbalance, insulin receptor nitration, and glucose intolerance

Calorie restriction is a dietary intervention known to improve redox state, glucose tolerance, and animal life span. Other interventions have been adopted as study models for caloric restriction, including nonsupplemented food restriction and intermittent, every-other-day feedings. We compared the short- and long-term effects of these interventions to ad libitum protocols and found that, although all restricted diets decrease body weight, intermittent feeding did not decrease intra-abdominal adiposity. Short-term calorie restriction and intermittent feeding presented similar results relative to glucose tolerance. Surprisingly, long-term intermittent feeding promoted glucose intolerance, without a loss in insulin receptor phosphorylation. Intermittent feeding substantially increased insulin receptor nitration in both intra-abdominal adipose tissue and muscle, a modification associated with receptor inactivation. All restricted diets enhanced nitric oxide synthase levels in the insulin-responsive adipose tissue and skeletal muscle. However, whereas calorie restriction improved tissue redox state, food restriction and intermittent feedings did not. In fact, long-term intermittent feeding resulted in largely enhanced tissue release of oxidants. Overall, our results show that restricted diets are significantly different in their effects on glucose tolerance and redox state when adopted long-term. Furthermore, we show that intermittent feeding can lead to oxidative insulin receptor inactivation and glucose intolerance. (C) 2011 Elsevier Inc. All rights reserved.

Tempol ameliorates murine viral encephalomyelitis by preserving the blood-brain barrier, reducing viral load, and lessening inflammation

Multiple sclerosis (MS) is a progressive inflammatory and/or demyelinating disease of the human central nervous system (CNS). Most of the knowledge about the pathogenesis of MS has been derived from murine models, such as experimental autoimmune encephalomyelitis and vital encephalomyelitis. Here, we infected female C57BL/6 mice with a neurotropic strain of the mouse hepatitis virus (MHV-59A) to evaluate whether treatment with the multifunctional antioxidant tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy) affects the ensuing encephalomyelitis. In untreated animals, neurological symptoms developed quickly: 90% of infected mice died 10 days after virus inoculation and the few survivors presented neurological deficits. Treatment with tempol (24 mg/kg, ip, two doses on the first day and daily doses for 7 days plus 2 mM tempol in the drinking water ad libitum) profoundly altered the disease outcome: neurological symptoms were attenuated, mouse survival increased up to 70%, and half of the survivors behaved as normal mice. Not Surprisingly, tempol substantially preserved the integrity of the CNS, including the blood-brain barrier. Furthermore, treatment with tempol decreased CNS vital titers, macrophage and T lymphocyte infiltration, and levels of markers of inflammation, such as expression of inducible nitric oxide synthase, transcription of tumor necrosis factor-alpha and interferon-gamma, and protein nitration. The results indicate that tempol ameliorates murine viral encephalomyelitis by altering the redox status of the infectious environment that contributes to an attenuated CNS inflammatory response. overall, our study supports the development of therapeutic strategies based on nitroxides to manage neuroinflammatory diseases, including MS. (C) 2009 Elsevier Inc. All rights reserved.

Proteomic analysis of dorsolateral prefrontal cortex indicates the involvement of cytoskeleton, oligodendrocyte, energy metabolism and new potential markers in schizophrenia

Schizophrenia is likely to be a consequence of serial alterations in a number of genes that, together with environmental factors, will lead to the establishment of the illness. The dorsolateral prefrontal cortex (Brodmann`s Area 46) is implicated in schizophrenia and executes high functions such as working memory, differentiation of conflicting thoughts, determination of right and wrong concepts, correct social behavior and personality expression. We performed a comparative proteome analysis using two-dimensional gel electrophoresis of pools from 9 schizophrenia and 7 healthy control patients` dorsolateral prefrontal cortex aiming to identify, by mass spectrometry, alterations in protein expression that could be related to the disease. In schizophrenia-derived samples, our analysis revealed 10 downregulated and 14 upregulated proteins. These included alterations previously implicated in schizophrenia, such as oligodendrocyte-related proteins (myelin basic protein and transferrin), as well as malate dehydrogenase, aconitase, ATP synthase subunits and cytoskeleton-related proteins. Also, six new putative disease markers were identified, including energy metabolism, cytoskeleton and cell signaling proteins. Our data not only reinforces the involvement of proteins previously implicated in schizophrenia, but also suggests new markers, providing further information to foster the comprehension of this important disease. (C) 2008 Elsevier Ltd. All rights reserved.

Lithium reduces Gsk3b mRNA levels: implications for Alzheimer Disease

There is evidence of increased systemic expression of active GSK3B in Alzheimer`s disease patients, which apparently is associated with the formation of senile plaques and neurofibrillary tangles. Due to its central role in the pathogenesis of AD, GSK3B is currently a promising target of the pharmaceutical industry. Whilst trials with specific GSK inhibitors in AD are under way, major attention has been focused on the neuroprotective effects of lithium. Whereas the direct and indirect inhibitory effects of lithium over GSK3 activity have been documented by several groups, its effects over Gsk3 transcription have not yet been addressed. We used quantitative PCR to evaluate the transcriptional regulation of Gsk3a and Gsk3b in lithium-treated primary cultures of rat cortical and hippocampal neurons. We found a significant and dose-dependent reduction in the expression of Gsk3b, which was specific to hippocampal cells. This same effect was further confirmed in vivo by measuring Gsk3 expression in different brain regions and in peripheral leukocytes of adult rats treated with lithium. Our studies show that LiCl can modulate Gsk3b transcription in vitro and in vivo. This observation suggest new regulatory effects of lithium over Gsk3b, contributing to the better understanding of its mechanisms of action, offering a new and complementary explanation for Gsk3b modulation and reinforcing its potential for the inhibition of key pathological pathways in Alzheimer`s disease.

Influência do sistema anteoxidante da catalase no ciclo do glioxilato durante o estabelecimento pós-germinativo de cártamo (Carthamus tinctorius L.) e de girassol (Helianthus annuus L.)

Oilseeds are a high-value natural resource, due to its use as a substitute for petroleum. However, the storage time can reduce seed viability and oil quality. Therefore, scientific efforts have been made to provide a increment of storage time, germination rates and plant establishment of high-value oilseeds. The seedling establishment depends of the plant pass over the functional transition stage, characterized by a metabolic change from heterotrophic condition to autotrophic one. The storage oil mobilization is performed by β-oxidation process and the glyoxylate cycle. Also, the functional transition involves acclimation to photosynthetic condition, which generally includes the participation of antioxidant system and the reactive oxygen species, the latter are produced in various reactions of primary and secondary metabolism. In the present study, Catalase was inhibited during the functional transition of sunflower and safflower, after were performed many analyzes to elucidate the effects caused on the SOD and APX antioxidant systems. Also, were checked the changes in expression pattern of the glyoxylate cycle enzymes markers, ICL and MLS. It was observed that after CAT inhibition, the SOD and APX antioxidant systems allow the seedling establishment. Besides, was verified that both oilseeds can be accelerate the reverse mobilization and the photosynthetic establishment when Catalase activity has dramatically decreased

Análise metagenômica da microbiota de ambientes aquáticos do estado do Rio Grande do Norte - Brasil

The screening for genes in metagenomic libraries from soil creates opportunities to explore the enormous genetic and metabolic diversity of microorganisms. Rivers are ecosystems with high biological diversity, but few were examined using the metagenomic approach. With this objective, a metagenomic library was constructed from DNA soil samples collected at three different points along the Jundiaí-river (Rio Grande do Norte-Brazil). The points sampled are from open area, rough terrain and with the direct incidence of sunlight. This library was analyzed functionally and based in sequence. For functional analysis Luria-Bertani solid medium (LB) with NaCl concentration varied from 0.17M to 0.85M was used for functional analysis. Positives clones resistant to hypersaline medium were obtained. The recombinant DNAs were extracted and transformed into Escherichia coli strain DH10B and survival curves were obtained for quantification of abiotic stress resistance. The sequences of clones were obtained and submitted to the BLASTX tool. Some clones were found to hypothetical proteins of microorganisms from both Archaea and Bacteria division. One of the clones showed a complete ORF with high similarity to glucose-6-phosphate isomerase which participates in the synthesis of glycerol pathway and serves as a compatible solute to balance the osmotic pressure inside and outside of cells. Subsequently, in order to identify genes encoding osmolytes or enzymes related halotolerance, environmental DNA samples from the river soil, from the water column of the estuary and ocean were collected and pyrosequenced. Sequences of osmolytes and enzymes of different microorganisms were obtained from the UniProt and used as RefSeqs for homology identification (TBLASTN) in metagenomic databases. The sequences were submitted to HMMER for the functional domains identification. Some enzymes were identified: alpha-trehalose-phosphate synthase, L-ectoina synthase (EctC), transaminase L-2 ,4-diaminobutyric acid (EctB), L-2 ,4-diaminobutyric acetyltransferase (EctA), L-threonine 3 dehydrogenase (sorbitol pathway), glycerol-3-phosphate dehydrogenase, inositol 3-phosphate dehydrogenase, chaperones, L-proline, glycine betaine binding ABC transporter, myo-inositol-1-phosphate synthase protein of proline simportadora / PutP sodium-and trehalose-6-phosphate phosphatase These proteins are commonly related to saline environments, however the identification of them in river environment is justified by the high salt concentration in the soil during prolonged dry seasons this river. Regarding the richness of the microbiota the river substrate has an abundance of halobacteria similar to the sea and more than the estuary. These data confirm the existence of a specialized response against salt stress by microorganisms in the environment of the Jundiaí river

Estudo de polimorfismos em genes relacionados ao metabolismo do ácido fólico e sua associação com o desenvolvimento de fendas orais não-sindrômicas

The congenital facial clefts are characterized by incomplete formation of the structures that separate the oral and nasal cavity. It is known that several environmental and genetic factors are involved in its development, among these, polymorphisms associated with folic acid metabolism have been investigated. In this sense, the objective was to observe the frequency of polymorphisms C677T and A1298C methylenetetrahydrofolate reductase gene (MTHFR), methionine synthase A2756G of (MTR), A66G of methionine synthase reductase (MTRR) A80G and the reduced folate carrier (RFC1) in patients with non-syndromic oral clefts, trying to match them with their development. Methods: We studied 140 patients with non-syndromic oral clefts and their mothers and 175 control subjects with their mothers, who underwent a questionnaire to obtain family information. Were collecting blood for DNA extraction from patients and their mothers to identify the genotypes of both by PCRRFLP, in addition to carrying out the determination of glucose, AST, ALT and serum creatinine, folic acid and vitamin B12 Serum and plasma homocysteine, and the hemogram. Results: Most patients have cleft lip and palate (55.8%), followed by isolated cleft palate (24.2%) and cleft lip (20%). Regarding gender, 62% of patients were male and 48% female and, after subdivision of the type of screwdriver according to sex was found a prevalence of males in the cracks of the type lip and palate (69 %) and lip (69.2%) and in the case of cleft palate was a female predominance (59%). The average concentration of serum folate in the group of mothers of cleft patients was significantly lower (13.8 ± 2.4 ng / mL) compared with the group of mothers of control subjects (18.8 ± 3.4 ng / mL) This was also observed for the group of cleft children as compared to controls, the dosage of folic acid had a significant difference with values of 15.6 ± 0.6 (ng / mL) and 17.9 ± 0.6 (ng / mL), respectively. For the biochemical measurements of glucose, AST, ALT and creatinine were not statistically different, nor was observed for haematological parameters performed. In assessing the frequency of polymorphisms C677T and A1298C MTHFR, A2756G MTR, MTRR A66G and A80G of the RFC1 there was no statistically significant difference in genotype distribution between cases and controls both for mothers and in the cleft. Conclusion: Although not observed association of polymorphisms with the development of cracks, the decrease in serum folate in the group of cleft patients and their mothers may reflect a disturbance in the metabolism of this metabolite, necessitating further studies such as studies methylation and expression to further elucidate the involvement of folate in the development of oral clefts

Nucleus isthmi and control of breathing in amphibians

Despite recent advances, the mechanisms of neurorespiratory control in amphibians are far from understood. One of the brainstem structures believed to play a key role in the ventilatory control of anuran amphibians is the nucleus isthmi (NI). This nucleus is a mesencephalic structure located between the roof of the midbrain and the cerebellum, which differentiates during metamorphosis; the period when pulmonary ventilation develops in bullfrogs. It has been recently suggested that the NI acts to inhibit hypoxic and hypercarbic drives in breathing by restricting increases in tidal volume. This data is similar to the influence of two pontine structures of mammals, the locus coeruleus and the nucleus raphe magnus. The putative mediators for this response are glutamate and nitric oxide. Microinjection of kynurenic acid (an ionotropic receptor antagonist of excitatory amino acids) and L-NAME (a non-selective NO synthase inhibitor) elicited increases in the ventilatory response to hypoxia and hypercarbia. This article reviews the available data on the role of the NI in the control of ventilation in amphibians. (C) 2004 Elsevier B.V. All rights reserved.

Role of brain nitric oxide in the thermoregulation of broiler chicks

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

Sucrose and nitrogen supplies regulate growth of maize kernels

The growth of maize (Zea mays L.) kernels depends on the availability of carbon (C) and nitrogen (N) assimilates supplied by the mother plant and the capacity of the kernel to use them. Our objectives were to study the effects of N and sucrose supply levels on growth and metabolism of maize kernels. Kernel explants of Pioneer 34RO6 were cultured in vitro with varying combinations of N (5 to 30 mM) and sucrose (117 to 467 mM). Maximum kernel growth was obtained with 10 mM N and 292 mM sucrose in the medium, and a deficiency of one assimilate could not be overcome by a sufficiency of the other. Increasing the N supply led to increases in the kernel sink capacity (number of cells and starch granules in the endosperm), activity of certain enzymes (soluble and bound invertases, sucrose synthase, and aspartate aminotransaminase), starch, and the levels of N compounds (total-N, soluble protein, and free amino acids), and decreased the levels of C metabolites (sucrose and reducing sugars). Conversely, increasing the sucrose supply increased the level of endosperm C metabolites, free amino acids, and ADPG-PPase and alanine transaminase activities, but decreased the activity of soluble invertase and concentrations of soluble protein and total-N. Thus, while C and N are interdependent and essential for accumulation of maximum kernel weight, they appear to regulate growth by different means. Nitrogen supply aids the establishment of kernel sink capacity, and promotes activity of enzymes relating to sucrose and nitrogen uptake, while sucrose regulates the activities df invertase and ADPG-PPase. (C) 1999 Annals of Botany Company.

The role of nitric oxide in the regulation of the systemic and pulmonary vasculature of the rattlesnake, Crotalus durissus terrificus

The functional role of nitric oxide (NO) was investigated in the systemic and pulmonary circulations of the South American rattlesnake, Crotalus durissus terrificus. Bolus, intra-arterial injections of the NO donor, sodium nitroprusside (SNP) caused a significant systemic vasodilatation resulting in a reduction in systemic resistance (Rsys). This response was accompanied by a significant decrease in systemic pressure and a rise in systemic blood flow. Pulmonary resistance (Rpul) remained constant while pulmonary pressure (Ppul) and pulmonary blood flow (Qpul) decreased. Injection of L-Arginine (L-Arg) produced a similar response to SNP in the systemic circulation, inducing an immediate systemic vasodilatation, while Rpul was unaffected. Blockade of NO synthesis via the nitric oxide synthase inhibitor, L-NAME, did not affect haemodynamic variables in the systemic circulation, indicating a small contribution of NO to the basal regulation of systemic vascular resistance. Similarly, Rpul and Qpul remained unchanged, although there was a significant rise in Ppul. Via injection of SNP, this study clearly demonstrates that NO causes a systemic vasodilatation in the rattlesnake, indicating that NO may contribute in the regulation of systemic vascular resistance. In contrast, the pulmonary vasculature seems far less responsive to NO.

Growth Regulation and Other Secondary Effects of Herbicides

As all herbicides act on pathways or processes crucial to plants, in an inhibitory or stimulatory way, low doses of any herbicide might be used to beneficially modulate plant growth, development, or composition. Glyphosate, the most used herbicide in the world, is widely applied at low rates to ripen sugarcane. Low rates of glyphosate also can stimulate plant growth (this effect is called hormesis). When applied at recommended rates for weed control, glyphosate can inhibit rust diseases in glyphosate-resistant wheat and soybean. Fluridone blocks carotenoid biosynthesis by inhibition of phytoene desaturase and is effective in reducing the production of abscisic acid in drought-stressed plants. Among the acetolactate synthase inhibitors, sulfometuron-methyl is widely used to ripen sugarcane and imidazolinones can be used to suppress turf species growth. The application of protoporphyrinogen oxidase inhibitors can trigger plant defenses against pathogens. Glufosinate, a glutamine syntherase inhibitor, is also known to improve the control of plant diseases. Auxin agonists (i.e., dicamba and 2,4-D) are effective, low-cost plant growth regulators. Currently, auxin agonists are still used in tissue cultures to induce somatic embryogenesis and to control fruit ripening, to reduce drop of fruits, to enlarge fruit size, or to extend the harvest period in citrus orchards. At low doses, triazine herbicides stimulate growth through beneficial effects on nitrogen metabolism and through auxin-like effects. Thus, sublethal doses of several herbicides have applications other than weed control.

Efeito do déficit hídrico na eficiência de herbicidas e nas características bioquímicas de picão-preto

The objective of this work was to evaluate conditions the effectiveness of acetolactate synthase (ALS) and protoporphyrinogen oxidase (PROTOX) inhibitors in the Bidens pilosa control under two water deficit conditions, as well as to determine the influence of water deficit under the contents of soluble carbohydrates and protein of weed. The experimental design was randomized completely design with the treatments, with four replications, setup in a factorial scheme 4x2, with four herbicides (fomesafen lactofen, chlorimuron-ethyl and imazethapyr), and two water conditions (-0.5 MPa and -0.01MPa). At 7, 14, 21 and 28 days after application (DAA), was assessed visually control efficiency of herbicides. For the determination of organic solutes plants were collected at 24, 48, 72 and 96 hours after application (HAA). Herbicides controlled efficiently plants of B. pilosa, except lactofen, whereas the water deficit affected the efficiency of control of all the herbicides. The soluble carbohydrate content increased with the imposition of water deficit, however, herbicides and water deficit further reduction of soluble proteins in plants of B. pilosa.

Seletividade de herbicidas aplicados em pós-emergência sobre capim-braquiária

O estudo foi conduzido com o objetivo de avaliar a seletividade de alguns herbicidas inibidores de ALS e FS II aplicados em pós-emergência em plantas de Brachiaria brizantha cv. Marandu e Brachiaria decumbens cv. Basilisk em condições de campo e seu efeito na qualidade das sementes. Os herbicidas testados (em g/ha) foram: imazethapyr a 100; chlorimuronethyl a 15; nicosulfuron a 50; bentazon a 720; e atrazine a 3.000, além de uma testemunha, sem aplicação de herbicidas. Dois experimentos em campo foram instalados em delineamento em blocos casualizados com quatro repetições e os ensaios de laboratório em delineamento inteiramente casualizado, com 16 repetições. Todos os herbicidas testados tiveram algum efeito de fitointoxicação visual aos cultivares avaliados. O nicosulfuron foi o herbicida que visualmente proporcionou os níveis mais elevados de injúrias às plantas de B. decumbens e B. brizantha. A produção de MS de B. brizantha nos estádios iniciais de crescimento foi reduzida pelos herbicidas nicosulfuron e atrazine, enquanto, em B. decumbens, apenas o herbicida nicosulfuron ocasionou redução da produção de MS. A qualidade das sementes de ambos os cultivares foi afetada pelo nicosulfuron, que induziu a dormência em sementes de B. decumbens, reduziu a porcentagem de sementes normais e, assim como o atrazine, aumentou a porcentagem de sementes mortas.

Isomaltulose production from Sucrose by Protaminobacter rubrum immobilized in calcium alginate

Different culture conditions for Protaminobacter rubrum and enzymatic reaction parameters were evaluated with the goal of improving isomaltulose production. P. rubrum was grown in a medium with 1% (w/v) cane molasses and 0.5% yeast extract and achieved a maximum cell yield Y(x/s) of 0.295 g of cells/g sucrose and a specific growth rate (mu) of 0.192 h(-1). The immobilization of P. rubrum cells was carried out with calcium alginate, glutaraldehyde and polyethyleneimine. Stabile immobilized cell pellets were obtained and used 24 times in batch processes. Enzymatic conversion was carried out at different sucrose concentrations and in pH 6 medium with 70% (w/v) sucrose at 30 degrees C an isomaltulose yield of 89-94% (w/v) was obtained. The specific activity of the P. rubrum immobilized pellets in calcium alginate at 30 degrees C ranged from 1.6 to 4.0 g isomaltulose g(-1) pellet h(-1), respectively with 70% and 65% sucrose solution, while in lower sucrose concentration had higher specific activities presumably due to substrate inhibition of the isomaltulose synthase in higher sucrose concentrations. (C) 2009 Elsevier Ltd. All rights reserved.