957 resultados para Conversão da lactose


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Objetivou-se neste experimento estudar o efeito do transporte de sêmen equino, entre haras, sobre a fertilidade de éguas inseminadas. Setenta e seis fêmeas da raça Mangalarga Marchador foram distribuídas, ao acaso, com número desigual de repetições, para se estudarem os efeitos do sêmen in natura, transportado ou não, e do sêmen diluído, resfriado e transportado, sobre a fertilidade de éguas e diferentes características reprodutivas. O sêmen foi diluído no diluidor lactose-gema de ovo sem glicerina. As fêmeas foram inseminadas, em dias alternados, com sêmen de apenas um garanhão, com volumes/dose inseminante variáveis dependendo do número de fêmeas a serem inseminadas por dia com determinado ejaculado. Utilizou-se para o transporte do sêmen um contêiner especialmente projetado para este fim (MSP-1). As taxas de concepção ao primeiro ciclo e totais, a eficiência de prenhez, o número de ciclos/égua, ciclos/égua gestante, ciclo/prenhez e prenhez/ciclo, o número de IA/égua, o número de IA/égua gestante e o número de IA/égua vazia não foram influenciados pelos tratamentos. O diluidor de lactose gema, modificado pela retirada do glicerol de sua formulação, constitui uma opção para a diluição do sêmen a ser resfriado e transportado. O suceso do transporte do sêmen, diluído e resfriado, a pequenas distâncias, por período de tempo curto, depende mais de um bom diluídor que de um sofisticado contêiner de transporte.

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Ingestion of transgalactosylated oligosaccharides (TOS) and other non-digestible oligosaccharides (NDOs) induces a significant increase in Bifidobacterium, Lactobacillus and some desirable species of Streptococcus populations in the gut of human and other animals (prebiotic effect). This change in the intestinal flora is responsible for several beneficial physiological effects such as a decrease of putrefactive products in the feces, lower blood cholesterol content, higher Ca2+ absorption, a smaller loss of bone tissue in ovariotomized female rats and a lower incidence of colon cancer. beta-Galactosidase from Penicillium simplicissimum, a strain isolated from soil, showed high galactosyltransferase activity when incubated with a highly concentrated lactose solution. Optimum pH and temperature ranges for hydrolytic activity were 4.0-4.6 and 55-60 degrees C, respectively, for a lactose concentration of 5.0% (w/v). Maximal galactosyltransferase activity was obtained at pH 6.5 and 50 degrees C and TOS synthesis was positively associated with lactose concentration in the reaction medium. Thus, when 50 ml of a 60% (w/v) lactose solution was incubated with 26.6 U of beta-galactosidase under the best pH and temperature conditions for transferase activity, a final product with 30.5% TOS (183 mg ml(-1)), 27.5% residual lactose and 42.0% monosaccharides was obtained. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

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Ninety-seven Mangalarga Marchador mares were allocated in a randomized experimental design, with different number of replicates per treatments. The objective of this experiment was to study the effect of raw (T3) or diluted, cooled semen transported to the breeding farms 1 (T1) and 3 (T2), on mare fertility and different aspects of reproductive efficiency. The mares were inseminated, with semen of only one stallion (Farm 2), on alternate days using different inseminating volumes, according to number of inseminated mares per day using only one ejaculate. For transportation, semen diluted in a lactose-egg yolk modified extender and the MSP-2 container were used. There was no difference among treatments in relation to conception rates of mares inseminated with raw or diluted, cooled and transported semen. Regardless of the farm, the total fertility obtained with cooled semen was 80% (52/65). The following variables were not affected by the treatments: cycles/mare, cycles/pregnant mare, cycles/pregnancy, pregnancy/cycle, number of inseminations/mare, number of inseminations/pregnant mare, number of inseminations/open mare and efficiency of pregnancy. However, the breeding farm had an effect on water and semen temperature in the container, time between collection and insemination, according to time and distance covered. Based on the results, cooling and transporting equine semen, using an extender, lactose-egg yolk without glycerine and the MSP-2 container should be recommended for short distances. The use of raw semen immediately after collection is also recommended.

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Filamentous haemagglutinin adhesin (FHA) is an important virulence factor from Bordetella pertussis related to the adhesion and spread of the bacteria through the respiratory tract. Three distinct domains have been characterized in mature FHA, and among them, the FHA(442-863) fragment was suggested to be responsible for the heparin-binding activity. In this study, we cloned the gene encoding the HEP fragment (FHA(430-873)) in a Lactobacillus casei-inducible expression vector based on the lactose operon. The recombinant bacteria, transformed with the resulting construct (L. casei-HEP), were able to express the heterologous protein depending on the sugar added to the culture. Subcutaneous inoculation of L. casei-HEP in Balb/C mice, using the cholera toxin B subunit as adjuvant, induced systemic anti-HEP antibodies that were able to inhibit in vitro erythrocyte haemagglutination induced by FHA. This is the first example of a B. pertussis antigen produced in lactic acid bacteria and opens new perspectives for alternative vaccine strategies against whooping cough.

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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.

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During 90 days 243 finishing feedlot animals from two genetic groups, were weighed every 28 days in a randomized experimental procedure in a 2 x 3 factorial arrangement, with two breeds - Nelore (Nel) and Canchim (Can) - and three treatments: water (A), cane stillage + magnesium oxide (V) and cane stillage + magnesium oxide + sodium bicarbonate (V + B). The diet for all treatments was composed of 70% of corn silage and 30% of chopped sugar cane ad libitum plus 1 kg of ground corn and 1,5 kg of soluble yeast per animal. Results showed higher weight gain (P < 0,01) of the Can group relation to those of Nel, having respectively 1,35 and 1,22 kg/head/day. Both Can and Nel groups showed higher weight gain (P <.01) when fed with V + B, with 1,44 and 1,32 kg/head/day respectively when comparing to the other diets: Can (A) = 1,30; Can (V) = 1,31; Nel (A) = 1,16 and Nel (V) = 1,20 kg/head/day. The diet using V + B has also showed a tendency (.05

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A simple, precise, rapid and low-cost potentiometric method for saccharin determination in commercial artificial sweeteners is proposed. Saccharin present in several samples of artificial sweeteners is potentiometrically titrated with silver nitrate solution using a silver wire as the indicator electrode, coupled to a titroprocessor. The best pH range was from 3.0 to 3.5 and the detection limit of sodium saccharin was 2.5 mg/ml. Substances normally found along with saccharin in several commercial artificial sweeteners such as maltodextrin, glucose, sucrose, fructose, aspartame, cyclamate, caffeine, sorbitol, lactose, nitrate, methyl- and n-propyl-p-hydroxybenzoate, benzoic, citric and ascorbic acids do not interfere even in significant amounts (e.g. 20 excess relative to saccharin). Chloride ion interferes when present in concentrations larger than 10 mg l(-1); this interference is eliminated with previous extraction of the sweetener from the aqueous medium with ethyl acetate. The results obtained by applying the proposed method compared very favorably with those given by the HPLC method recommended by the FDA. (C) 2003 Elsevier Ltd. All rights reserved.

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A simple, precise, fast and low-cost potentiometric method for alendronate determination in pharmaceutical formulations has been proposed. Alendronate present in tablets at the known concentration was potentiometrically titrated in an aqueous solution using a combined glass electrode coupled with an autotitrator. Determination limit of alendronate was 20.0 mug mL(-1). In the presence of common excipients, such as lactose, microcrystalline cellulose, glucose, croscarmellose sodium, starch, talc, magnesium stearate and titanium dioxide no interferences were observed. The method proposed was validated by determining alendronate in various dosage forms. The average RSD was 0.75%.

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The effects of extender and farms on the fertility of sixty-five Mangalarga Marchador breed mares were studied. The mares were randomly assigned to a 2 x 2 factorial experiment, with two breeding farms (H1 and H2) and two extenders (glycine-egg yolk-T1 and lactose-egg yolk modified-T2), from only one stallion, with different number of replicates. The mares were inseminated, on alternated days, with diluted, cooled, transported semen, in a special container (MSP-2). There were no differences in the conception rate at first cycle, regardless of the breeding farm or extender used. Also. there was no difference among breeding farm or extender concerning the conception rate/cycle and the following reproductive characteristics: number of cycles/pregnancy, number of inseminations/mare, inseminations/pregnant mare, inseminations/open mare, water temperature in the container, temperature of semen in the container, time between collection and insemination and efficiency of pregnancy. The use of lactose-egg yolk modified extender for the dilution, cooling and transport of stallion semen between farms is recommended. The new container MSP-2 showed to be a option for the transportation between farms, for the same purpose.

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This study was carried out to determine the best digestible energy and digestible protein ratio in feeds for Nile tilapia (Oreochromis niloticus) juveniles 30.0 +/- 4.21 g) based on digestible amino acids and the ideal protein concept). Twelve rations were formulated with protein levels 22.0; 26.0; 30.0 and 34.0% of digestible protein and levels 3,000, 3,300 and 3,600 kcal/kg digestible energy. The digestible energy/digestible protein ratio was between 8.94 and 15.19 kcal/g. Three hundred and twenty four tilapias were randomly distributed in thirty six 250 L circular tanks at a density of 9 fish/tank, a total of 12 treatments with three replications. After 60 days, there was no significant difference in weight gain, daily weight gain and feed conversion ratio among the studied treatments. A linear increase was observed in fillet yield with increasing digestible protein. With respect to feed cost/kg weight gain, the treatment with 30.0% DP and 3,000 kcal/kg DE presented low cost and better cost effectiveness index. Therefore, it was concluded that digestible energy did not influence the productive performance parameters and that effective feeds can be formulated with DP levels lower than 34% when feeding juvenile tilapias. The ration should be formulated based on the concept of ideal protein.

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The objective was to evaluate the effect of beta-lactoglobulin (beta-lg) polymorphism and seasonality on milk composition (fat, lactose, total solids, milk urea nitrogen, total protein, true protein, casein and somatic cell counts) of Holstein and Girolando cows. Milk and blood samples from 278 Holsteins cows and 156 Girolando cows were taken during two dry seasons and two rainy seasons, for milk composition analysis and to determine beta-lg genotypes, respectively. BB genotype was the most frequent for both breeds, followed by AA genotype for Holstein (BB>AA>AB) and by AB for Girolando cows (BB>AB>AA). No differences were found in milk compositional characteristics among genetic variants of beta-lg (AA, AB and BB) either between Holstein or Girolando cows. No association between milk composition and beta-lg genetic polymorphism was observed. During the dry season, independently of the breed considered, higher contents of lactose, true protein, casein and casein :true protein ratio were found.

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During the growth of Kluyveromyces marxianus var. marxianus ATCC 10022 on lactose, peaks of glucose, but not β-galactosidase activity, were detected in culture medium. Harvested and washed whole cells produced glucose and galactose from lactose, or ortho-nitro-phenol from the chromogenic substrate ortho-nitro-phenyl-β-D-galactopyranoside (ONPG), indicating that β-galactosidase is physically associated with cells. ONPG hydrolysis by whole cells presented a monophasic kinetics (Km 36.6 mM) in lactose exponential growth phase cells, but a biphasic kinetics (Km 0.2 and 36.6 mM) in stationary growth phase cells. Permeabilization with digitonin or disruption of cells from both growth phases led to monosite ONPG hydrolysis (Km 2.2 to 2.5 mM), indicating that β-galactosidase is not located in the periplasm. In addition, the energy inhibitors fluoride or arsenate, as well as the uncouplercarbonyl cyanide m-chlorophenylhydrazone (CCCP) prevented ONPG hydrolysis by whole cells. These findings indicate that energy coupled transmembrane transport is the rate-limiting step for intracellular ONPG cleavage. The taxonomic and physiologic implications of the exclusive intracellular location of β-galactosidase of K. marxianus var. marxianus ATCC 10022 are discussed. © 1996 Kluwer Academic Publishers.

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An actinomycete strain (Ar386) was isolated from the soil of the Araraquara regio, SP, Brazil. The strain, named Streptomyces jacareensis, formed irregular rayed, rugose, grayish-white mycelium with sinuous, branched hyphae carrying rare isolated spores; assimilated glucose, galactose, inositol, ribose, maltose, sucrose, melibiose and starch but not mannitol, rhamnose, arabinose, xylose, lactose and raffinose; and contained LL- diaminopimelic acid in its cell wall. An antibiotic active against Gram- positive bacteria, which was characterized as being 26-deoxylaidlomycin and which may have application against poultry coccidiosis, was isolated from cultures of the strain. This was the first isolation of this antibiotic from a microorganism of the genus Streptomyces and also the first isolation of this antibiotic in Brazil.

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The objective of this work was to evaluate the nutritive value of pigeon pea meal (PPM) with methionine substituting soybean meal (SM) in diets for 1-28 day-old broiler chicks. The experimental design was that of random blocks, in a 3 × 3 factorial scheme with three substitution levels - 15,30 and 45% - and three methionine supplementation levels in relation to the requirements, that is: 100, 66 and 33%, with four repetitions. It was found that PPM treated for 20 minutes at 100°C substituted up to 30% of the SM, even without methionine supplementation, in relation to liveweight (p<0.01), to food conversion and to the efficiency of utilization of metabolizable energy and to protein (p<0.05). At the 66% level of methionine supplementation, the same results as for these parameters were obtained at all of the levels of substitution of SM by PPM. The 30% or 45% substitution of SM protein by that of PPM affected (p<0.01) the efficiency of methionine utilization. The sulphur amino acid utilization efficiency was affected (p<0.01) beginning at 66% methionine supplementation in the diets.

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To evaluate the nutritional value of African palm kernel meal (Elaeis guineensis) on the performance of Nile tilapia (Oseochromis niloticus), five isonitrogenous (30% crude protein), isoenergetic (2,800 Kcal/kg of digestible energy), and isofibrous (10% crude fiber) diets, with increasing levels of African palm kernel meal (0, 7, 14, 21, 28 and 35%) were fed ad libitum for 18 weeks to Nile tilapia (Oreochromis niloticus) fingerlings, averaging 1.52 ± 0.04 g of body weight, housed for 120 days in 60 liter aquaria with six fingerlings. To determine the production traits, weight gain, apparent food conversion, specific growth rate, protein efficiency ratio, weight gain percentage, net protein utilization, and body composition, fish were weighted at six-week intervals. Statistical analysis of recorded data were performed through multivariate profile analysis and polynomial regression models. Results showed that feeding fingerling Nile tilapia with ratios containing up to 35% of African palm kernel meal does not affect production performance.