The use of the oxidative stress responses as biomarkers in Nile tilapia (Oreochromis niloticus) exposed to in vivo cadmium contamination

Water contaminants have a high potential risk for the health of populations. Protection from toxic effects of environmental water pollutants primarily involves considering the mechanism of low level toxicity and likely biological effects in organisms who live in these polluted waters. The biomarkers assessment of oxidative stress and metabolic alterations to cadmium exposure were evaluated in Nile tilapia, Oreochromis niloticus. The fish were exposed to 0.35, 0.75, 1.5, and 3.0 mg/l concentrations of Cd2+ (CdCl2) in water for 60 days. Fish that survived cadmium exposure showed a metabolic shift and a compensatory development for maintenance of the body weight gain. We observed a decreased glycogen content and decreased glucose uptake in white muscle. Lactate dehydrogenase (LDH) and creatine phosphokinase (CK) activities were also decreased, indicating that the glycolytic capacity was decreased in this tissue. No alterations were observed in total protein content in white muscle due to cadmium exposure suggesting a metabolic shift of carbohydrate metabolism to maintenance of the muscle protein reserve. There was an increase in glucose uptake, CK increased activity, and a clear increase of LDH activity in red muscle of fish with cadmium exposure. Since no alterations were observed in lipoperoxide concentration, while antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were changed in the liver and the red and white muscle of fish with cadmium exposure, we can conclude that oxygen free radicals are produced as a mediator of cadmium toxicity. Resistance development is related with increased activities of antioxidant enzymes, which were important in the protection against cadmium damage, inhibiting lipoperoxide formation. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Seasonal metabolic depression, substrate utilisation and changes in scaling patterns during the first year cycle of tegu lizards (Tupinambis merianae)

The tegus increase in body mass after hatching until early autumn, when the energy intake becomes gradually reduced. Resting rates of oxygen consumption in winter drop to 20% of the values in the active season (Vo(2)=0.0636 ml g(-1) h(-1)) and are nearly temperature insensitive over the range of 17-25degreesC (Q(10)=1.55). During dormancy, plasma glucose levels are 60% lower than those in active animals, while total protein, total lipids and beta-hydroxybutyrate are elevated by 24%, 43% and 113%, respectively. In addition, a significant depletion of liver carbohydrate (50%) and of fat deposited in the visceral fat bodies (24%) and in the tail (25%) and a slight loss of skeletal muscle protein (14%) were measured halfway through the inactive period. Otherwise, glycogen content is increased 4-fold in the brain and 2.3-fold in the heart of dormant lizards, declining by the onset of arousal. During early arousal, the young tegus are still anorexic, although Vo(2) is significantly greater than winter rates. The fat deposits analysed are further reduced (62% and 45%, respectively) and there is a large decrease in tail muscle protein (50%) together with a significant increase in glycogen (2-3-fold) and an increase in plasma glucose (40%), which suggests a role for gluconeogenesis as a supplementary energy source in arousing animals. No change is detectable in citrate synthase activity, but beta-hydroxyacyl CoA dehydrogenase activities are strongly affected by season, reaching a Mold and 5-fold increase in the liver tissue of winter and arousing animals, respectively, and becoming reduced by half in skeletal muscle and heart of winter animals compared with late fall or spring active individuals. From hatching to late autumn, the increase of the fat body mass relatively to body mass is disproportionate (b=1.44), and the mass exponent changes significantly to close to 1.0 during the fasting period. The concomitant shift in the Vo(2) mass exponent in early autumn (b=0.75) to values significantly greater than 1.0 in late autumn and during winter dormancy indicates an allometric effect on the degree of metabolic depression related to the size of the fat stores and suggests greater energy conservation in the smaller young.

Efeitos da correção da acidose metabólica com bicarbonato de sódio sobre o catabolismo protéico na insuficiência renal crônica

A desnutrição protéico-energética constitui problema comum aos pacientes com insuficiência renal crônica, influenciando diretamente na sua morbi-mortalidade. A acidose metabólica tem papel no catabolismo protéico, ativando a via proteolítica proteasoma-ubiquitina, dependente de adenosina trifosfato, e conjuntamente com glicocorticóides induz uma maior atividade na desidrogenase que degrada os aminoácidos de cadeia ramificada. Esta revisão teve como objetivo descrever o mecanismo pelo qual a acidose metabólica nos pacientes com insuficiência renal crônica promove o catabolismo protéico, favorecendo assim a desnutrição, bem como avaliar os efeitos do uso de bicarbonato de sódio na correção da acidose e conseqüentemente redução do catabolismo protéico. Pesquisas mostram melhora da acidose pelo uso de bicarbonato de sódio e conseqüente redução do catabolismo protéico na insuficiência renal crônica, podendo ser esta uma conduta promissora na atenuação da desnutrição nestes pacientes.

FUNCTIONAL ALPHA-TROPOMYOSIN PRODUCED IN ESCHERICHIA-COLI - A DIPEPTIDE EXTENSION CAN SUBSTITUTE THE AMINO-TERMINAL ACETYL GROUP

Unlike the muscle protein, alpha-tropomyosin expressed in Escherichia coli does not bind actin, does not exhibit head-to-tail polymerization, and does not inhibit actomyosin ATPase activity in the absence of troponin. The only chemical difference between recombinant and muscle tropomyosins is that the first methionine is not acetylated in the recombinant protein (Hitchcock-DeGregori, S. E., and Heald, R. W. (1987) J. Biol. Chem. 262, 9730-9735). We expressed three fusion tropomyosins in E. coli with 2, 3, and 17 amino acids fused to its amino terminus. Ah three fusions restored actin binding, head-to-tail polymerization, and the capacity to inhibit the actomyosin ATPase to these unacetylated tropomyosins. Unlike larger fusions, the small fusions of 2 and 3 amino acids do not interfere with regulatory function. Therefore the presence of a fused dipeptide at the amino terminus of unacetylated tropomyosin is sufficient to replace the function of the N-acetyl group present in muscle tropomyosin. A structural interpretation for the function of the acetyl group, based on our results and the coiled coil structure of tropomyosin, is presented.

Effects of leucine supplemented diet on intestinal absorption in tumor bearing pregnant rats

Background: It is known that amino acid oxidation is increased in tumor-bearing rat muscles and that leucine is an important ketogenic amino acid that provides energy to the skeletal muscle.Methods: To evaluate the effects of a leucine supplemented diet on the intestinal absorption alterations produced by Walker 256, growing pregnant rats were distributed into six groups. Three pregnant groups received a normal protein diet (18% protein):pregnant (N), tumor-bearing (WN), pair-fed rats (Np). Three other pregnant groups were fed a diet supplemented with 3% leucine (15% protein plus 3% leucine):leucine (L), tumor-bearing (WL) and pair-fed with leucine (Lp). Non pregnant rats (C), which received a normal protein diet, were used as a control group. After 20 days, the animals were submitted to intestinal perfusion to measure leucine, methionine and glucose absorption.Results: Tumor-bearing pregnant rats showed impairment in food intake, body weight gain and muscle protein content, which were less accentuated in WL than in WN rats. These metabolic changes led to reduction in both fetal and tumor development. Leucine absorption slightly increased in WN group. In spite of having a significant decrease in leucine and methionine absorption compared to L, the WL group has shown a higher absorption rate of methionine than WN group, probably due to the ingestion of the leucine supplemented diet inducing this amino acid uptake. Glucose absorption was reduced in both tumor-bearing groups.Conclusions: Leucine supplementation during pregnancy in tumor-bearing rats promoted high leucine absorption, increasing the availability of the amino acid for neoplasic cells and, mainly, for fetus and host utilization. This may have contributed to the better preservation of body weight gain, food intake and muscle protein observed in the supplemented rats in relation to the non-supplemented ones.

Reação metabólica à infecção no hospedeiro.

At the site of local reaction to infection the interleukin-1 (1L-1) is released signaling to distant tissues the presence of infection and attempting to strengthen the host's defenses and inhibit the bacterial growth. This phenomenon is accompanied by anorexia and fever. The muscle-protein breakdown is sustained and the released amino acids are taken up by the liver and other RE structures where they are used as substrates for energy and for synthesis of defense-related proteins. The metabolic adaptations to sepsis include hyperthermia, increased synthesis of hepatic globulins, development of granulopoiesis and neutrophilia and redistribution of serum iron and trace minerals.

O uso das pregas cutâneas e da circunferência muscular do braço no diagnóstico de desnutrição energético-protéica em pacientes adultos: estudo crítico.

The use of anthropometric measurements of triceps (TSF) and subscapular skinfolds (SSF) and mid-upper arm muscle circumference (MAMC) was examined as far as the diagnosis of energy-protein malnutrition (EPM) is concerned. The study was undertaken in five groups of patients (n = 231): arterial hypertension (AH, n = 63), chronic obstructive pulmonary disease (COPD, n = 17), hemodialyzed chronic renal failure (CRF, n = 19), critically ill patients with an acute event (CA, n = 42) and critically ill patients with chronic diseases (CCD, n = 90). The results were compared to those obtained in a group of healthy individuals (control group, n = 102). The control group and the group of patients were allocated in subgroups according to sex and age (less than 50 and more than 50 years). It was expected that significant differences would be found for the anthropometric values between the control subgroups and the COPD, the CRF and the CCD subgroups of patients. For the skinfold thicknesses (TSF and SSF), significant differences were found between CRF, CCD subgroups and the control subgroups under fifty years of age; however, the differences were not significant when the subgroups over fifty were analyzed. Concerning the MAMC, significant differences were found: 1 degree) between the CRF subgroups (males and females) and the control subgroups under fifty years of age; 2 degrees) between the CCD male subgroups (younger and older subgroups) and the respective control subgroups and 3 degrees) between the COPD and the control subgroups.(ABSTRACT TRUNCATED AT 250 WORDS)

Efeitos do tratamento oral com sulfato de vanadila em ratos diabeticos jovens

This work intends to evaluate the effects of oral vanadyl treatment (VOSO 4, 1 mg/mL) in young streptozotocin-diabetic rats during 19 and 29 days. In several times of treatment the rats were monitored to determine body weight, food and water intakes, glycemia, and the urinary excretion of glucose and urea. The animals were killed in the 19(th) and 29(th) days, and the glycemia level was determined again, as well as the weight of pancreas, muscles (Soleus and Extensor digitorum longus - EDL) and adipose tissues (epididymal and retroperitoneal). The results showed that the treatment of young diabetic rats with VOSO 4 promotes the reduction of hyperglycemia (p < 0.01), food (p < 0.01) and water intakes (p < 0.05) and body weight (p < 0.05). Neither the tissues and pancreas weights nor the urinary urea level of the treatment group varied in comparison to the control group. In conclusion, the vanadyl treatment in the studied period is able to reduce the main metabolic alterations often found in diabetes. These data are very useful and important for the future experiments to verify the effects of vanadyl sulfate on muscle protein metabolism in diabetic rats.

Efeitos do treinamento físico prévio sobre a severidade do diabetes induzido por dose única de aloxana em ratos

Pós-graduação em Ciências da Motricidade - IBRC

Spirulina e exercício na recuperação de ratos submetidos à desnutrição protéica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diferentes protocolos de treinamento na prevenção do Diabetes mellitus em ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Proteínas do soro de queijo: hidrólise e formulação de suplemento alimentar para ratos Wistar

Pós-graduação em Alimentos e Nutrição - FCFAR

Metabolic and Behavior Changes in Surubim Acutely Exposed to a Glyphosate-Based Herbicide

This study examined the effect of glyphosate-based herbicide (Roundup Original), the major herbicide used in soybean crops in Mato Grosso state, at concentrations of 0, 2.25, 4.5, 7.5, and 15 mg L-1 on metabolic and behavior parameters of the hybrid fish surubim in an acute exposure lasting 96 h. Glycogen content, glucose, lactate, and protein levels were measured in different tissues. Plasma levels of cholesterol, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were also determined. Ventilatory frequency (VF) and swimming activity (SA) were considered behavior parameters. Results showed that herbicide exposure decreased plasma glucose levels and increased it in surubim liver. Lactate increased in both plasma and liver but decreased in muscle. Protein levels decreased in plasma and muscle but increased in liver. After herbicide exposure, liver and muscle glycogen was decreased. Cholesterol levels decreased in plasma at all concentrations tested. Plasma ALT increased, and no alterations were recorded for AST levels. VF increased after glyphosate exposure (5 min) and decreased after 96 h. SA showed differences among all groups (5 min). At the end of 96 h, SA was altered by the 7.5 mg L-1 concentration. Fish used anaerobic glycolysis as indicated by generally decreased glycogen levels and decreased lactate levels in muscle but increased ones in plasma and liver. We suggest that the studied parameters could be used as indicators of herbicide toxicity in surubim and may provide extremely important information for understanding the biology of the animal and its responsiveness to external stimuli (stressors).

Métodos analíticos para a identificação de espécies animais

The food industry has been rapidly modernized, and with this the disposal and the consumption of industrialized food has been increasing continually. These products lose their original morphological characteristics, requiring fast and reliable tests that could help to identify the species in question, as most fraudulent behavior in the milk and dairy industry (meat and fish) is carried out where there is partial or total exchange of the original material for other with less value at market. Nowadays there is a lot of techniques that can be used for the identification of animal species, based on muscle protein, or DNA analysis. In the case of protein based analysis, we can mention several types of electrophoresis and immunologic methods, as ELISA. In the case of DNA based methods, we have several assays that use the amplification of DNA fragments, known as PCR, as proof. All these techniques have advantages and disadvantages that can be affected by factors- the sample condition, or the degree of relation between the species in question. Because of this, it’s necessary that a continuous study looking for the improvement of the available techniques, making sure that the confirmation of food authenticity is in place. This is to ensure the true product value, to comply with labeling regulationand and protect the consumer of frauds

Condição corporal e jejum sobre o metabolismo energético e crescimento de juvenis de pacu

Pós-graduação em Zootecnia - FCAV