Influence of temperature on the properties of the xylanolytic enzymes of the thermotolerant fungus Aspergillus phoenicis

This study reports on the effects of growth temperature on the secretion and some properties of the xylanase and beta-xylosidase activities produced by a thermotolerant Aspergillus phoenicis. Marked differences were observed when the organism was grown on xylan-supplemented medium at 25 degreesC or 42 degreesC. Production of xylanolytic enzymes reached maximum levels after 72 h of growth at 42 degreesC; and levels were three- to five-fold higher than at 25 degreesC. Secretion of xylanase and beta-xylosidase was also strongly stimulated at the higher temperature. The optimal temperature was 85 degreesC for extracellular and 90 degreesC for intracellular beta-xylosidase activity, independent of the growth temperature. The optimum temperature for extracellular xylanase increased from 50 degreesC to 55 degreesC when the fungus was cultivated at 42 degreesC. At the higher temperature, the xylanolytic enzymes produced by A. phoenicis showed increased thermo stability, with changes in the profiles of pH optima. The chromatographic profiles were distinct when samples obtained from cultures grown at different temperatures were eluted from DEAE-cellulose and Biogel P-60 columns.

Efeito de diferentes relações volumoso: concentrado no consumo, digestibilidade aparente e partição da digestão da dieta de bovinos

Three steers equipped with ruminal and duodenal cannulas were fed roughage:concentrate ratios 80:20, 60:40 and 40:60 in order to study intake and apparent, rumen and post-rumen digestibilities. The roughage was ''coast cross'' (Cynodon dactylon) hay (5.67% CP and 83.30% NDF). Undigestible neutral detergent fiber (NDF) was used as dry matter (DM) flow marker. DM intake means were 77.99, 91.03 and 91.81g DM/kg BW0.75, for the 20, 40 and 60% concentrate diets, respectively. DM intake for the 20% diet was statistically (P < 0.05) different from the other two diets. Apparent digestion coefficient (%) of DM (50.48, 57.32 and 61.33), organic matter (OM) (52.03, 58.91 and 62.76) and gross energy (GE) (48.95, 56.40 and 60.00) increased significantly with the increase in concentrate ratio of the diets. For the following components the apparent digestion coefficients were not statistically different: NDF (44.54, 45.28 and 42.53), ADF (40.69 44.39 and 43.60), cellulose (51.54, 54.34 and 52.03), hemicellulose (49.63, 46.78 and 39.18) and starch (86.59, 91.89 and 93.21). DM, OM, NDF, ATF, cellulose and starch ruminal and post-ruminal digestibilities were not statistically different. But the ruminal digestibilities of hemicellulose (94.81, 90.26 and 85.99) and EG (93.85, 83.30 and 78.77) decreased significantly as the concentrate ratio of the diets increased. The post-ruminal digestibility of hemicellulose (5.19, 9.74 and 14.03%) and GE (6.12, 16.20 and 21.23%) increased as the concentrate ratio of the diets increased.

Measurements of ambient ozone using indigo blue-coated filters

Ozone monitoring techniques utilize expensive instruments that are often large and heavy. These instruments are not easy to handle in the field, and their size also limits some sampling schemes, principally for indoor ozone determination. We have developed a lightweight, inexpensive, and sensitive method that offers flexibility to undertake measurements of ambient ozone in many environments, both indoor and outdoor. The method is based on the reaction of ozone with indigo blue dye. The indigo molecule contains 1 carbon double bond (C = C) that reacts with ozone and results in nearly colorless reaction products. During sample collection, 2 cellulose filters coated with 40 mu L of 1.0 x 10(-3) M indigo blue were used. The determinations were done spectrophotometrically at 250 and 600 nm. The analytical parameters studied were sampling time and flow rate. Analytical curves were constructed with concentrations ranging from 37 to 123 parts per billion by volume (ppbv) of standard ozone, at 0.4 L/min and 15 min sampling time. The detection limits achieved were 6 and 9 ppbv, respectively, at 250 and 600 nm. Considering interferences, measurements made at 250 nm gave more reliable and specific values for ozone.

ISOLATION AND IN-VITRO HYDROLYSIS OF GLOBULIN G1 FROM LENTILS (LENS-CULINARIS, MEDIK)

The major globulin fraction from lentil seeds was investigated with respect td in vitro hydrolysis by trypsin and chymotrypsin. Globulin was isolated by a NaCl-ascorbate extraction procedure and purified by DEAE-cellulose chromatography and gelfiltration chromatography on Sepharose CL-6B. The purity and identification of the protein were performed by PAGE. The native globulin, with a molecular weight of 375 kD, was resolved by SDS-PAGE into twelve polypeptides with molecular weights ranging from 61 to 14.5 kD. Native and heated globulin GI was hydrolyzed with trypsin and chymotrypsin. SDS-PAGE indicated that native globulin was more resistant to digestion than heated protein. Amino acid analysis of the major globulin revealed that glutamic acid was present in the largest concentration, followed by aspartic acid, arginine and leucine. As is also the case for other legumin-like globulins, lentil GI was deficient in sulfur-containing amino acids.

Partial purification and some properties of a T2 ribonuclease from Aspergillus flavipes

A ribonuclease was partially purified from the culture medium of Aspergillus flavipes (IZ:1501), after 96 h of cultivation by chromatography on DEAE-cellulose and Sephadex G100 columns. The molecular weight of the RNase was estimated to be 40 kD by gel filtration using Sephadex G100, and the optimum pH and temperature were 4.0 and 50-55 degrees C, respectively. Catalytic activity was inhibited by Zn+2, Fe+3, Hg+2 and Ag+ ions. The enzyme did not show an exact base specificity and produced four kinds of 3'-nucleotides from yeast RNA.

Valor nutritivo do feno de Brachiaria decumbens Stapf cv. Basilisk submetido a tratamento com amônia anidra ou uréia

The effects of the ammoniation of Brachiaria decumbens hay was evaluated. The hay bales were distributed into a complete randomized block design, with four replications and they were submitted to the treatments: untreated or treated with anhydrous ammonia (NH3)(2,0 and 3,0% of the DM) or with urea (3,6 and 5,4% of the DM). All the hays bales remained under plastic cover for 45 days. After three days of aeration, samples were collected for the determination of the chemical composition, nitrogenous compounds fraction and the in vitro dry matter (IVDDM) and organic matter (IVDOM) digestibility. In the metabolic study, Saanen goats breed was used in a 5x5 Latin squares design, where the apparent digestibility, the voluntary intake and the nutritive value index were evaluated. The ammoniation increased the contents of the total N, N ammonia (N-NH3) and non-protein N, with high effect on the levels of 3,0% of NH3 and 5,4% of urea. There were no differences between the level of 3,0% of NH3 and 5,4% of urea for the total N, N-NH3 and NPN. However, the treatment with 3,0% of NH3 allowed a larger fixation of N in ADIN and NDIN forms. The ammoniation increased the IVDMD and IVDMO and reduced the contents of neutral detergent fiber (NDF), hemicellulose, acid detergent fiber (ADF) and lignin, but it did not alter the cellulose and gross energy contents. The ammoniation increased the DM, OM, CP, NDF, ADF, hemicellulose, cellulose and gross energy apparent digestibility and as well as the voluntary intake of DM, digestible DM, digestible OM, digestible protein, digestible energy and the nutritive value index. The ammoniation increased the hay nutritive value index, but there were no differences between the levels of NH3 and urea.

Uso de indicadores para estimar fluxos de matéria seca ileal em eqüinos fistulados

This experiment was carried out with six half-bred Bretao-Campolinacolts with ileum fistulated to evaluate the difference in the ileum dry matter flow estimated by chromic oxide, cellulose, NDF, lignin and fecal lignin through the collection of ileum samples digesta at 28 h intervals, totalizing six samples per animal, starting at 10:00 a.m. The animals were fed ad libitum with the following diets: R1: clephantgrass, R2: elephantgrass plus ground corn, and R3: elephantgrass plus ground corn plus soybean meal. The data was statistically described, based on the coefficient of variation. The values of dry matter prececal digestion coefficients were, respectively, for diets 1, 2 and 3, at six schedules, for cellulose (-16.4; 21.4 and 6.6%), NDF(-34.7; 28.8 and -12.8%), to lignin (-51.5; -5.1 and -25.7%), in two schedules for cellulose (-13.4; 25.6 and 21.5%), fecal lignin (-37.1, 16.6 and -6.4%) and chromic oxide (-219.3, 36.4 and 9.5%). The coefficients of variation were, respectively, for the diets i, 2 and 3, at six schedules, for cellulose (148.3; 107.5 and 522.7%), NDF (95.4; 80.9 and 314.3%), lignin (210.2; 752.3 and 209.6%), at two schedules for cellulose(148.5; 80.7 and 70.0%), fecal lignin, (262.4; 177.9 and 723.5%) and chromic oxide (141.1; 158.9 and 473.4%). In diet i, the ileum dry matter now were over estimated for all markers, showing that chosen collection lime to estimate the flows were not adequate. Based on the coefficient of variation of the diets 2 and 3, the cellulose at two schedules was the most marker indicator to determine the ileum dry matter flow.

BIOSENSORS FOR GLUCOSE NEEDLE-SHAPED FOR IN-VIVO MONITORING

Different procedures for obtaining a needle biosensor for the determination of glucose to be inserted subcutaneously in vivo, have been compared. Platinum wires with a diameter of 75 mum, teflon-coated were inserted in hypodermic needles and fixed with a two-component epoxy resin. Using a dip-coating procedure, several layers were deposited on electrodes. The first coating was cellulose acetate, the second was immobilized glucose oxidase (GOD) mixed with bovine serum albumin (BSA) and glutaraldheyde, the third coating was a polyurethane coating obtained with commercially available products. A large number of electrodes have been tried and statistically evaluated but they seem to be affected by poor reproducibility evidenced by a large spreading in successive calibration curves. Then, the polyurethane coating has been replaced by a thin polycarbonate membrane salinized and fixed on the tip of the needle. Reproducible results were achieved and first results of in vivo measurements on rabbits are reported.

Estudo das propriedades de troca iônica e/ou adsorção da celulose e celuloses modificadas

In this work it was studied the capacity of cellulose and chemically modified celluloses (carboxymethylcellulose, cellulose phosphate and oxicellulose) to adsorb copper(II) cations of aqueous and non aqueous solutions. The influence of the principal physical chemical parameters on the adsorption process was examined using the batch adsorption method and copper(II) perchlorate solutions, the maximum adsorption capacity determined for adsorbents were as follows (mol.g(-1)): cellulose, 0.54 . 10(-5); carboxymethylcellulose, 1.28 . 10(-4); cellulose phosphate, 1.12 . 10(-4); oxicellulose, 0.38 . 10(-4).

Peroxidase from peach fruit: Thermal stability

Peroxidase from peach fruit was purified 28.9-fold by DEAE-cellulose, Sephadex G-100 and hydroxylapatite chromatography. The purified enzyme showed only one peak of activity with an optimum pH of 5.0 and temperature of 40 degreesC. The calculated activation energy (Ea) for the reaction was 7.97 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 80 degreesC with a fast inactivation at 80 degreesC. PAGE of the inactivation course at 70 degreesC showed only one band of activity. Different sugars increased the heat stability of the activity in the following order: sucrose>lactose>glucose>fructose. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar concentrations (10 to 40%, w/w) with the Ea for inactivation increasing with sucrose concentration from 0 to 20% (w/w). After inactivation at 70 degreesC and 75 degreesC the enzyme was able to be reactivated by up to 40% of the initial activity when stared at 30 degreesC.

Purification and characterization of beta-fructosidase with inulinase activity from Aspergillus niger-245

Aspergillus niger - 245 a strain isolated from soil samples showed good beta -fructosidase activity when inoculated in medium formulated with dahlia extract tubers. The enzyme was purified by precipitation in ammonium sulphate and percolated in DEAE-Sephadex A-50 and CM-cellulose columns, witch showed a single peack in all the purification steps, maintaining the I/S ratio between 0.32 to, 0.39. Optimum pH for inulinase activity (I) was between 4.0 - 4.5 and for invertase activity (S) between 2.5 and 50. The optimum temperature was 60 degrees .C for both activities and no loss in activity was observed when it was maintained at this temperature for 30 min. The K-m value was 1.44 and 5.0 respectively, for I and S and V-m value 10.48 and 30.55 respectively. The I activity was strongly inhibited by Hg2+ and Ag+ and 2 x 10(-3) M of glucose, but not by fructose at the same concentration. The enzyme showed an exo-action mechanism acting on the inulin of different origins. In assay conditions total hydrolysis of all the frutans was obtained although it has shown larger activity on the chicory inulin than that one from artichoke Jerusalem and dahlia, in the first 30 min. The obtained results suggested that the enzyme presented good potential for industrial application in the preparing the fructose syrups.

Estádio de Desenvolvimento do Milho. 2. Efeito sobre o Consumo e a Digestibilidade da Silagem em Ovinos

Corn plants were ensiled at the milk, milk-early dough, medium dough, and semi-hard dough stages. The intake and digestibility trials showed that: a) silage DM and NFE contents increased and ADF, cellulose, and lignin contents decreased with plant maturity; b) corn plant maturity had little effect on the digestibility of the silages, but the milk and medium dough stages produced the best results; c) no consistent effect of maturity was observed in DM and CP daily intakes (mean values 41.86 and 26.77/g/kg(75), respectively). Nevertheless, daily digestible dry matter and digestible protein intakes (g/kg(75)) were higher with medium-dough grains (31.74 and 1.97g, respectively) than with the milk (23.27 and 1.45g, respectively) and the milk-early dough stages (22.60 and 1.28g, respectively). However, similar intakes were observed with the medium-dough and semi-hard dough stages. Total digestible nutrient contents of the silages were affected little by corn plant maturity. Nevertheless, statistical differences were Found between the medium dough (70.09%) and the milk-early dough stages (63.07%).

Efeitos da amonização sobre o valor nutritivo do feno de capim-braquiária

This work was conducted to determine the effects of ammoniation and supplementation on the nutritive value of signal grass (Brachiaria decumbens Stapf) hay. The hay was treated with anhydrous ammonia (3.0% DM) and introduced into the rations for sheep with 12.00% of CP, identified as T1 grass hay without NH3 + cotton seed meal; T2 = treated hay (3.0% de NH3); T3 = treated hay (3.0% de NH3) + com grain meal; T4 = hay + cotton seed meal + corn grain meal. nit: following coefficients of digestibility were determined for T1, T2, T3 e T4, respectively: DM (54.90; 55.50); 54.50; and 56.12%); NI)I: (51.36; 60.20; 55.30; and 48.35%); ADF (47.36; 58.66; 56.03; and 47.07%); hemicellulose (58.80; 63.32; 56.00; and 49.70%); cellulose (55.58; 71.80; 68.07; and 58.21%); lignin (10.10; 32.18; 31.74; and 0.72%) and protein (64.6; 59.36; 56.16; and 70. 15%). nle N balances for T1, T2, T3 and T4 were 5.69; 3.88; 3.90; and 8,82 g N/day. It was concluded that the ammoniation was equivalent to the vegetable protein supplementation in the rations. Furthermore, this treatment showed a greater potential to increase fiber digestion, particulary for ADF and cellulose.

Effect of ammoniation and moisture-content on the quality of signal grass (Brachiaria-decumbens stapf) hay

The experiment was carried out to evaluate the effects of two moisture levels (18-20% and 13-15%) and three anhydrous ammonia levels (0.0; 1.5; 3.0% of NH3) on the quality of Brachiaria decumbens Stapf hay. The hay was bailed in April and weighed and treated under plastic cover during 30 days. The hay presented a similar chemical composition when bailed with high or low moisture. The percentages of NDF (80.59; 77.61; 76.10%); hemicellulose (32.56; 29.48; 28.76%) and lignin (9.53; 8.21; 7.54% decreased and the percentages of crude protein (4.04; 11.35; 13.22%) and IVDMD (36.78; 49.72; 54.33%) increased as the NH3 level increased. The fractions ADF, cellulose, and ADIN did not change due to the ammoniation. The incidence of fungi decreased with application of NH3 being the better results obtained with the 1.5% treatments.

Determination of oligoelements in parenteral formulations by planar chromatography and spectrophotometry

The authors have studied the chromatographic behavior of parenteral preparations for pediatric use containing inorganic cations. After separation and identification by thin-layer chromatography, Mn2+, Zn2+, and Cu2+ were analyzed by a method based on reaction with an appropriate reagent and extraction with an organic solvent which yielded elution and preconcentration, resulting in an appropriate solution for colorimetric quantitation. Cr3+ cation was determined by atomic absorption spectrophotometry after appropriate chromatographic separation, using microcrystalline cellulose (adsorbent) and an acetone:water:hydrochloric acid mixture (80:5:8) as the mobile phase.