867 resultados para biochemical ecology


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The aim of this work is to obtain, purify and characterize biochemically a peroxidase from Copaifera langsdorffii leaves (COP). COP was obtained by acetone precipitation followed by ion-exchange chromatography. Purification yielded 3.5% of peroxidase with the purification factor of 46.86. The COP optimum pH is 6.0 and the temperature is 35 ºC. COP was stable in the pH range of 4.5 to 9.3 and at temperatures below 50.0 ºC. The apparent Michaelis-Menten constants (Km) for guaiacol and H2O2 were 0.04 mM and 0.39 mM respectively. Enzyme turnover was 0.075 s-1 for guaiacol and 0.28 s-1 for hydrogen peroxide. Copaifera langsdorffii leaves showed to be a rich source of active peroxidase (COP) during the whole year. COP could replace HRP, the most used peroxidase, in analytical determinations and treatment of industrial effluents at low cost.

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Lipases are characterised mainly by catalytic versatility and application in different industrial segments. The aim of this study was to biochemically characterise a lipase from a new strain of Bacillus sp. ITP-001. The isoelectric point and molecular mass were 3.12 and 54 kDa, respectively. The optima lipase activity was 276 U g-1 at pH 7.0 and a temperature of 80 ºC, showing greater stability at pH 5.0 and 37 ºC. Enzymatic activity was stimulated by various ions and pyridine, and inhibited by Cu+ and ethanol. The values of Km and v max were 105.26 mmol and 0.116 mmol min-1 g-1, respectively determined by the Eadie-Scatchard method.

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This work presents biochemical characterization of a lipase from a new strain of Bacillus sp. ITP-001, immobilized using a sol gel process (IB). The results from the biochemical characterization of IB showed increased activity for hydrolysis, with 526.63 U g-1 at pH 5.0 and 80 ºC, and thermal stability at 37 ºC. Enzymatic activity was stimulated by ions such as EDTA, Fe+3, Mn+2, Zn+2, and Ca+2, and in various organic solvents. Kinetic parameters obtained for the IB were Km = 14.62 mM, and Vmax = 0.102 mM min-1 g-1. The results of biochemical characterization revealed the improved catalytic properties of IB.

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The first objective of this study was to find out reliable laboratory methods to predict the effect of enzymes on specific energy consumption and fiber properties of TMP pulp. The second one was to find with interactive software called “Knowledge discovery in databases” enzymes or other additives that can be used in finding a solution to reduce energy consumption of TMP pulp. The chemical composition of wood and enzymes, which have activity on main wood components were presented in the literature part of the work. The results of previous research in energy reduction of TMP process with enzymes were also highlighted. The main principles of knowledge discovery have been included in literature part too. The experimental part of the work contains the methods description in which the standard size chip, crushed chip and fiberized spruce chip (fiberized pulp) were used. Different types of enzymatic treatment with different dosages and time were tested during the experiments and showed. Pectinase, endoglucanase and mixture of enzymes were used for evaluation of method reliability. The fines content and fiber length of pulp was measured and used as evidence of enzymes' effect. The refining method with “Bauer” laboratory disc refiner was evaluated as not highly reliable. It was not able to provide high repeatability of results, because of uncontrolled feeding capacity and refining consistency. The refining method with Valley refiner did not have a lot of variables and showed stable and repeatable results in energy saving. The results of experiments showed that efficient enzymes impregnation is probably the main target with enzymes application for energy saving. During the work the fiberized pulp showed high accessibility to enzymatic treatment and liquid penetration without special impregnating equipment. The reason was that fiberized pulp has larger wood surface area and thereby the contact area between the enzymatic solution and wood is also larger. Standard size chip and crushed chip treatment without special impregnator of enzymatic solution was evaluated as not efficient and did not show visible, repeatable results in energy consumption decrease. Thereby it was concluded that using of fiberized pulp and Valley refiner for measurements of enzymes' effectiveness in SEC decrease is more suitable than normal size chip and crushed chip with “Bauer” refiner. Endoglucanase with 5 kg/t dosage showed about 20% energy consumption decrease. Mixture of enzymes with 1.5 kg/t dosage showed about 15% decrease of energy consumption during the refining. Pectinase at different dosages and treatment times did not show significant effect on energy consumption. Results of knowledge discovery in databases showed the xylanase, cellulase and pectinase blend as most promising for energy reduction in TMP process. Surfactants were determined as effective additives for energy saving with enzymes.

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The exotic tree Muntingia calabura L. (Muntingiaceae), a species native to Central America, is used as fish feed and fiber and cellulose production in Brazil. This study was carried out in urban areas and verified the reproductive biology of this plant species. Flower and fruit morphology, compatibility system, reproductive phenology, pollination and frugivore animals, and germination of disseminated seeds were recorded by standard field and laboratory procedures. This tree is self-compatible and autonomously self-pollinated, with its flowers being mainly visited by bees and its fruits consumed by birds and bats. Germination of its dispersed seeds is fast and occurs at a high rate. The results of this work suggest that M. calabura is very adaptable to cultivated areas,thus being an excellent choice for urban reforestation. However, its reproductive characteristics place this plant as an invasive species with significant potential in southeastern Brazil.

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Physiological and biochemical aspects of assai palm during seed germination and early seedling growth were investigated. Seeds collected from plants growing in flooded and upland forests were used to determine the influence of normoxic (aerobic) and anoxic (anaerobic) conditions in germination and the initial and average time of development in the roots and shoots. After 75 days, seedlings germinated under normoxia were transferred to trays and submitted to flooding. Seed reserves (lipids, proteins, soluble sugars and starch) were monitored for quiescent and germinated seeds maintained under normoxic and anoxic conditions, as well as after 5, 10 and 20 days of seedling growth. Alcohol dehydrogenase (ADH) activity was quantified in roots and leaves of seedlings without or with flooding (partial and total). Seeds were not able to germinate under anoxia. Different strategies of storage mobilization of lipids, proteins, soluble sugars and starch were observed in seeds of each environment. ADH activity was induced by anoxia, with the highest level observed in the leaves. This study showed that, under normoxic conditions, the best developmental performance of assai palm seeds, from flooded or upland forest areas, during germination was associated with primary metabolites mobilization and seedling flooding tolerance with increased ADH activity. We conclude that the assai palm is well adapted to the anoxic conditions provoked by flooding.

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Studies on the effects of temperature and time of incubation of wastewater samples for the estimation of biodegradable organic matter through the biochemical oxygen demand (BOD), that nowadays are rare, considering that the results of the classic study of STREETER & PHELPS(1925) have been accepted as standard. However, there are still questions how could be possible to reduce the incubation time; whether the coefficient of temperature (θ) varies with the temperature and with the type of wastewater and if it approaches 1.047. Aiming the elucidation of these questions, wastewater samples of dairy, swine and sewage treated in septic tanks were incubated at temperatures of 20, 30 and 35 °C, respectively for 5, 3.16 and 2.5 days. From the parameter of deoxygenation coefficient at 20 °C (k20), θ30 and θ35 were calculated. The results indicated that θ values changes with the type of wastewater, however does not vary in the temperature range between 30 and 35 °C, and that the use of 1.047 value did not implied significant differences in obtaining k in a determined T temperature. Thus, it is observed that the value of θ can be used to estimate the required incubation time of the samples at different temperatures.

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OBJECTIVE: To assess hematological and biochemical features of splenic effluent blood and their influence on the rise of hematological values after splenectomy.METHODS: we studied 20 patients undergoing surgical treatment for schistosomatic portal hypertension. We collected blood samples for CBC, coagulation, bilirubin and albumin in the splenic vein (perioperative) and peripheral blood (immediately pre and postoperative periods).RESULTS: the splenic blood showed higher values of red blood cells, hemoglobin, hematocrit, platelet count, total leukocytes, neutrophils, lymphocytes, monocytes, eosinophils and basophils, as well as reduction of laboratory coagulation parameters in relation to peripheral blood collected preoperatively. In the postoperative peripheral blood there was an increase in the overall leukocytes and in their neutrophil component, and decreased levels of basophils, eosinophils and lymphocytes. The other postoperative variables of complete blood count and coagulation tests were not different compared with the splenic blood. The albumin values were lower postoperatively when compared to preoperative and splenic blood. There were higher values of direct bilirubin in the postoperative period when compared with the preoperative and splenic blood. Postoperative indirect bilirubin was lower compared to its value in the splenic blood.CONCLUSION: hematological and biochemical values of splenic effluent blood are higher than those found in peripheral blood in the presence of schistosomal splenomegaly. However, the splenic blood effluent is not sufficient to raise the blood levels found after splenectomy.

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The Brown brocket deer (Mazama gouazoubira) is the most common free-living and captive deer in South America, especially in Brazil, and has great ecological and scientific significance. However, data on hematological and biochemical parameters in brown brocket deer are scarce. The goal of this study was to establish reference ranges for hematological and biochemical parameters of Mazama gouazoubira, comparing differences during the seasons of the year and between sex. Blood samples from ten adult healthy brown brocket deer (6 female and 4 male) were collected during daytime, monthly, during 12 months. The animals were maintained in individual stable, protected from noise and fed ad libitum with commercial ration and green fodder. For blood collection, animals were submitted to physical restrain for no longer than 2 minutes. The following parameters were determined: red blood cell count (RBC), haemoglobin concentration, packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), white blood cell count (WBC), platelet count, enzyme activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT) and serum levels of alkaline phosphatase (ALP), creatine kinase (CK), total protein (TP), albumin, cholesterol, total calcium, ionic calcium, sodium, potassium, magnesium, triglycerides, creatinine and urea. Values were compared according to season and sex. RBC count, WBC count and MCV suggested seasonal influence. Haemoglobin concentration, PCV and MCV were influenced by sex. Serum concentration of total calcium, ionic calcium, sodium, potassium and magnesium were influenced by season. Serum magnesium was also influenced by sex. The blood parameters herein reported may be useful as reference values for diagnostic and prognostic purposes in captive brown-brocket deer.

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Horses used for the game of polo experience abrupt and frequent changes in exercise intensity. To meet this variable energy demand, the horses use both aerobic and anaerobic pathways in varying proportions and intensities. In this context, there must be a balance between the formation of reactive oxygen species (ROS) and the action of antioxidants to prevent oxidative stress and its consequences. The effect of supplementation with an ADE vitamin complex on oxidative metabolism was evaluated in 18 crossbred horses randomly divided between a treated group (TG) and a control group (CG). The TG animals received the ADE vitamin complex (1mL/50 kg of body weight) by deep intramuscular injection at 30 and 15 days before the game. The CG horses received 10ml of saline by the same administration route and schedule. During the polo match, the animals played for a total of 7.5 min. Blood samples were collected on the same days as the treatments were administered, and immediately before and at 15, 90 and 180 minutes after the game. The concentrations of creatine phosphokinase (CK), lactate dehydrogenase (LDH), lactate, glucose, aspartate aminotransferase (AST), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured in the blood samples. After the game, the TG demonstrated higher levels of AST, lactate and glucose than the CG, suggesting more efficient energy use by the treated animals. The higher GSH and lower lactate levels in the TG before the game suggest the presence of a greater antioxidant supply in the treated animals. The maintenance of the MDA levels indicates that neither of the groups exhibited oxidative stress.

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Abstract: Infection with Escherichia coli (E. coli) is a common disease in poultry industry. The use of antibiotics to treat diseases is facing serious criticism and concerns. The medicinal plants may be effective alternatives because of their multiplex activities. The aim of this study was to investigate the effects of cinnamon extract on the levels of liver enzymes, tumor necrosis factor-alpha (TNF-α) and nuclear factor-kappa B (NF-κB) gene expressions in liver of broiler chickens infected with E. coli. Ninety Ross-308 broilers were divided into healthy or E. coli-infected groups, receiving normal or cinnamon extract (in concentrations of 100 or 200mg/kg of food) supplemented diets. E. coli suspension (108cfu) was injected subcutaneously after 12 days cinnamon administration. Seventy-two hours after E. coli injection, the blood samples were taken for biochemical analysis of liver enzymes in serum (spectrophotometrically), and liver tissue samples were obtained for detection of gene expression of inflammatory markers TNF-α and NF-κB, using real-time PCR. Infection with E. coli significantly increased the levels of TNF-α and NF-κB gene expressions as well as some liver enzymes including creatine-kinase (CK), lactate-dehydrogenase (LDH), alanine-transferase (ALT) and aspartate-transferase (AST) as compared with control group (P<0.05). Pre-administration of cinnamon extract in broilers diet (in both concentrations) significantly reduced the tissue levels of TNF-α and NF-κB gene expressions and enzymes CK and ALT in serum of broiler chickens inoculated with E. coli in comparison with E. coli group (P<0.05 and P<0.01). The levels of LDH and AST were significantly decreased only by 200mg/kg cinnamon extract in infected broilers. The level of alkaline-phosphatase (ALP) was not affected in any groups. Pre-administration of cinnamon extract in diets of broiler chickens inoculated with E. coli could significantly reduce the gene expression levels of pro-inflammatory mediators and liver enzymes activities, thereby protecting the liver against this pathologic condition.

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Rhynchosia capitata is becoming an increasing problem in summer crops, such as cotton, soybean, pearl millet and mungbean in many Asian countries. Laboratory and greenhouse studies have been conducted to determine the effects of several environmental factors on seed germination patterns and seedling emergence of R. capitata. We investigated whether the diverse ecological factors such as temperature, light, salinity, moisture stress, pH, and soil depth affected germination and seedling emergence of R. capitata. Germination increased as temperature increased from 25ºC and significantly reduced at 45ºC. Presence or absence of light did not influence germination. Germination of R. capitata was sensitive to increased salt and moisture stress, as well as to seed burial depth. Only 48% of seeds germinated at 150 mM salt concentration compared to 100% in control (distilled water). Similarly, 15% of seeds germinated at an osmotic potential of ‑0.8 MPa compared to 88% at ‑0.2 MPa. The optimum pH for seed germination of R. capitata was 7 (98% germination), but the seeds also germinated at lower level of pH 5 (85%) and at higher level of pH 10 (75%). In seed burial trial, maximum seedling emergence of 93% occurred at 2 cm depth, and seedling did not emerge from a depth of 12 cm. The high germination ability of R. capitata under a wide range of ecological factors suggests that this species is likely to be the one to cause more problems in a near future, if not managed appropriately.

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Asphodelus tenuifolius is becoming a more common weed in rain-fed area in Pakistan. Laboratory and greenhouse experiments were conducted to determine the effect of different environmental factors on germination and emergence of A.tenuifolius. Results showed that A.tenuifolius can tolerate a wide range of varying environmental factors. Greatest percentage of germination (80%) was recorded at 15 ºC constant temperature; however, considerable germination occurred at 20 and 25 ºC. Light for 10 h photoperiod stimulate germination of Asphodelus tenuifolius compared with complete darkness. Germination was totally inhibited at osmotic stress higher than -0.8 MPa. There was no significant difference in germination at pH 6 to 8; however, there was a slightly decrease at pH 9, compared with distilled water. Asphodelus tenuifolius was very sensitive to salinity; however, a few seeds of A.tenuifolius were able to germinate even at 150 mM NaCl concentration. Greatest emergence occurred with seed placed at soil surface and emergence decreased with increase in burial depth. No emergence occurred from 4 cm or greater. This information may aid in developing tools and strategies for management.

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Aspects of population dynamics and life history of Paepalanthus polyanthus (Bong.) Kunth, a sand dune monocarpic plant, were evaluated. A five year study was carried out on three permanent plots (5 m x 5 m) in a sand dune slack at Joaquina beach, Santa Catarina State, Brazil. From December 1986 to June 1989, the population decreased due to the death of the post reproductive plants and a low emergence of seedlings. In June 1989, a great recruitment occurred, but no plants survived. The population re-established itself by 1990-1991. The emergence and high survival of seedlings depended on periods of high pluviosity. Nevertheless, the summer flooding and episodes of drought represented key factors in mortality. The birth and mortality rates varied among the areas. It is suggested that these differences are related with depth of the ground water and with vegetation cover at each site. Paepalanthus polyanthus can reproduce in the second year of life, but few plants do this. The chances of survival and reproduction increase with the size of the basal leaf rosette. Although the production of seeds increases with size, the risk of unexpected flooding, for instance, suggest that a great delay in reproduction might not be the most favorable strategy.