Histopathological and ultrastructural characteristics of myeloid leukosis in broiler chicken

Caracterizaram-se a linhagem e o grau de diferenciação das células neoplásicas no estudo histopatológico e ultraestrutural da leucose mielóide. Histologicamente as células neoplásicas apresentaram pleomorfismo, núcleos ovais, nucléolos proeminentes, cromatina distribuída de maneira irregular, figuras de mitose atípicas e moderada quantidade de citoplasma contendo granulações eosinofílicas esféricas. Essas características indicam a linhagem mielóide. Ultraestruturalmente evidenciaram-se células com núcleo oval, volumoso, eletrodenso, com predomínio de eucromatina e citoplasma com numerosos grânulos esféricos, eletrodensos e homogêneos, indicando mielócitos com diferenciação para eosinófilos. Constatou-se também a presença de partículas virais tipo-C no espaço intercelular dos túbulos renais, no interior de vesículas intracitoplasmáticas dos mielócitos imaturos presentes na medula óssea e ovário, e PCR positivo para ALV-J.

Extensive polymorphism and chromosomal characteristics of ribosomal DNA in the characid fish Triportheus venezuelensis (Characiformes, Characidae)

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

Growth responses and photosynthetic characteristics of wild and phycoerythrin-deficient strains of Hypnea musciformis (Rhodophyta)

The phycoerythrin-deficient strain (green phenotype) of Hypnea musciformis (Rhodophyta) originated from a green branch, which had arisen as a spontaneous mutation in a wild plant (brown phenotype) collected from the Brazilian coast. The present study describes the growth responses to irradiance, photoperiod and temperature variations, pigment contents, and photosynthetic characteristics of the brown and green strains of H. musciformis. The results showed that growth rates increased as a function of irradiance (up to 40 mu mol photons m(-2) s(-1)) but, with further increase in irradiance (from 40 to 120 mu mol photons m(-2) s(-1)), became light-saturated and remained almost unchanged. The highest growth rates of the brown and green strains were observed in temperatures of 20-25 degrees C under long (14:10 h LD) and short (10:14 h LD) photoperiods. The brown strain had higher growth rates than the green strain in the short photoperiod, which could be related to the high concentrations of phycobiliproteins. Phycoerythrin was not detected in the green strain. The brown strain had higher concentrations of allophycocyanin and phycoerythrin in the short photoperiod while the green strain had higher concentrations of phycocyanin. The brown strain presented higher photosynthetic efficiency (alpha), and lower saturation parameter (I-k) and compensation irradiance (I-c) than the green strain. The brown strain exhibited the characteristics of shade-adapted plants, and its higher value of photosynthetic efficiency could be attributed to the higher phycoerythrin concentrations. Results of the present study indicate that both colour strains of H. musciformis could be selected for aquaculture, since growth rates were similar (although in different optimal light conditions), as the green strain seems to be adapted to higher light levels than the brown strain. Furthermore, these colour strains could be a useful experimental system to understand the regulation of biochemical processes of photosynthesis and metabolism of light-harvesting pigments in red algae.

Effect of In concentration in the starting solution on the structural and electrical properties of ZnO films prepared by the pyrosol process at 450 degrees C

Undoped and indium-doped Zinc oxide (ZnO) solid films were deposited by the pyrosol process at 450 degrees C on glass substrates From solutions where In/Zn ratio was 2, 5, and 10 at.%. Electrical measurements performed at room temperature show that the addition of indium changes the resistance of the films. The resistivities of doped films are less than non-doped ZnO films by one to two orders of magnitude depending on the dopant concentration in the solution. Preferential orientation of the films with the c-axis perpendicular to the substrate was detected by X-ray diffraction and polarized extended X-ray absorption fine structures measurements at the Zn K edge. This orientation depends on the indium concentration in the starting solution. The most textured films were obtained for solutions where In/Zn ratio was 2 and 5 at.%. When In/Zn = 10 at.%, the films had a nearly random orientation of crystallites. Evidence of the incorporation of indium in the ZnO lattice was obtained from extended X-ray absorption fine structures at the In and Zn K edges. The structural analysis of the least resistive film (Zn/In = 5 at.%) shows that In substitutes Zn in the wurtzite structure. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Chemical Composition and fermentative characteristics of Elephant grass (Pennisetum purpureum Schum.) silages added of increasing levels of mango (Mangifera indica L.) byproducts

Aiming at evaluating the use of those byproducts on ruminant feeding an experiment has been carried out in the Forage Research department (www.npf.ufc.br), in order to evaluate the effects of addition of increasing levels of mango processing byproducts (MB) in Elephant grass silages. Twenty experimental silos made of PVC pipe (100 x 340 mm), in a completely randomized design with 5 levels of addition (0; 5; 10; 15; and 20%) of MB and 4 replications. Upon 32 days of ensilage, samples were collected for determination of levels of dry Matter (DM), crude protein (CP), ethereal extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicelluloses (HC), ammonia nitrogen (N-NH3), and pH values. Data were evaluated by analyses of variance and regression analyses using the F test at the 5% level. The levels of DM and CP increased of 0.50 and 0.03 percentage units, respectively, for every 1% of MB added. The levels of NDF and ADF decreased of 0.51 and 0.24 percentage units, respectively, for every 1% of MB added. The levels of N-NH3 decreased from 4 to 23 percentage units while pH values remained constant (p>0.05), with average values of 3.29. Addition of 20% of MB improved silages chemical composition by promoting an increase in the levels of MS and reduction in the levels of fiber.

GROWTH AND FERMENTATION CHARACTERISTICS OF NEW SELECTED STRAINS OF SACCHAROMYCES AT HIGH-TEMPERATURES AND HIGH CELL DENSITIES

Maintenance of high cell viability was the main characteristic of our new strains of thermotolerant Saccharomyces. Total sugar conversion to ethanol was observed for sugarcane juice fermentation at 38-40-degrees-C in less than 10 h and without continuous aeration of the culture. Invertase activity differed among the selected strains and increased during fermentation but was not dependent on cell viability. Invertase activity of the cells and optimum temperature for growth, as well as velocity of ethanol formation, were dependent on medium composition and the type of strain used. At high sugarcane syrup concentrations, the best temperature for ethanol formation by strain 781 was 35-degrees-C. Distinct differences among the velocities of ethanol production using selected strains were also observed in sugarcane syrup at 35-38-degrees-C.

Structural and physicochemical characteristics of lintnerized native and sour cassava starches

The comprehension of the structure of starch granules is important for the understanding of its physicochemical properties. Native and sour cassava starches after being analyzed with respect to their pasting properties and baking expansion capacity, were treated with 2.2 N HCl at 38 degreesC for a maximum of nine days. The starch granules remaining after lintnerization were analyzed for amylose content and intrinsic viscosity, by X-ray diffraction, scanning electron microscopy and chromatographic analysis. The results indicated that the acid hydrolysis on all starches occurred in two steps. The first one, with high hydrolysis rate, was characterized by a quick degradation of the amorphous part of the granules whereas the second step, with lower hydrolysis rate, was characterized by a higher resistance of the organized areas of the granules to acid treatment. Most of the amylose chains were found in the amorphous areas of starch granules only a small percentage was involved in the crystalline regions. The microscopic and chromatographic analysis demonstrated that the acid hydrolysis was not able to disrupt the entire granular crystalline structure. Fermented starch showed amylose and/or amylopectin chain fractions resistant to pullulanase, probably due to structural alterations during fermentation.

Effect of niobia on the crystal structure and dielectric characteristics of Pb(Zr0.45Ti0.55)O-3 prepared from polymeric precursor

The influence of niobia addition on the phase formation and dielectric properties of Pb(Zr0.45Ti0.55)O-3 powder prepared from polymeric precursor was analyzed. The weight fraction and unit-cell volume of the tetragonal phase decreased, and the mass fraction of the rhombohedral phase increased, with increasing niobia concentration. The rhombohedral unit-cell volume increased up to 5 mol% of added Nb and then decreased. Small amounts of pyrochlore and tetragonal zirconia phases were observed in PZT powder with more than 10 mol% Nb. These results were interpreted as an indication that the Nb ion was substituted for the zirconium ion in the tetragonal phase. For sintered PZT samples at 1100 degrees C, no free-zirconia phase was observed. The dielectric constant increased with the niobia addition up to 5 mol% and decreased for higher concentrations. The Curie temperature decreased with niobia addition up to 10 mol% before the formation of pyrochlore phase. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Some structural and physicochemical characteristics of tuber and root starches

Starches from six different species (cassava, arrowroot, sweet potato, yam, canna and ginger) were isolated and some structural and physicochemical characteristics analysed and correlated. Phosphorous and amylose contents were determined using a colorimetric method and measuring iodine affinity, respectively. Molecular weight distributions of starches were analysed by Sepharose CL 2B. Granular shape and size distribution were performed using an image analyser system attached to a light microscope. Swelling power was determined at 60, 70, 80 and 90 degrees C. Pasting and thermal properties were measured using a rapid viscoanalyser, and a differential scanning calorimeter, respectively. Phosphorous content varied from 0.007 to 0.031% for cassava and canna starches, respectively. Yam, canna and ginger starches displayed higher amylose contents (32.6, 31.7 and 26.5%, respectively) than cassava, arrowroot and sweet potato starches (19.8, 20.8 and 22.6%, respectively). These last three starches displayed amylose molecules of higher molecular weight than those shown for yam, canna and ginger starches. Canna starch showed higher proportions of longer branch chains of amylopectin than others starches. The size and shape of granules were quite variable among all starches and the average size of granules varied from 13.9 to 42.3 mu m for sweet potato and canna, respectively. Swelling power, pasting, and thermal properties were affected by structural characteristics of the starches.

Effects of biofertilizer rates on the structural, morphogenetic and productive characteristics of Piata grass

The objective of this study was to investigate the influence of different levels of biofertilizers from cattle and swine manure on the structural, morphogenetic and productive characteristics of Brachiaria brizantha cv. Piata. The experiment was arranged in a completely randomized factorial design with split plots. The plots were defined by eight treatments: two biofertilizers (cattle and swine), four levels (0, 100, 200 and 300 kg N.ha(-1)) and subplots by four different cutting periods. The cutting for plant uniformity was performed at 45 days after sowing at 15 cm above the soil surface. The biofertilizeres were applied in a single level, after the cutting of plants, in rates of 0, 0.23 and 0.19, 0.45 and 0.38, 0.68 and 0.57 liters pot(-1) for the biofertilizers from cattle and swine manure, respectively. These rates were also equivalent to levels of 0, 100, 200 and 300 kg N.ha(-1). There was no significant difference between the types of biofertilizers as there was no interaction between them and the different levels, hence both biofertilizers could be applied without any loss of nutrient intake by the plants used in this experiment. There was a significant difference between the production of green and dry matter, the leaf appearance rate, phyllochron, leaf and pseudostem elongation rates, number of green leaves, final leaf length, number and weight of tillers, according to the increase of nitrogen rates, following linear prediction model. Effect of the cutting periods was also observed, once the plants harvested during the summer presented greater performance of structural and morphogenetic characteristics.

Predicting body and carcass characteristics of 2 broiler chicken strains using support vector regression and neural network models

As a new modeling method, support vector regression (SVR) has been regarded as the state-of-the-art technique for regression and approximation. In this study, the SVR models had been introduced and developed to predict body and carcass-related characteristics of 2 strains of broiler chicken. To evaluate the prediction ability of SVR models, we compared their performance with that of neural network (NN) models. Evaluation of the prediction accuracy of models was based on the R-2, MS error, and bias. The variables of interest as model output were BW, empty BW, carcass, breast, drumstick, thigh, and wing weight in 2 strains of Ross and Cobb chickens based on intake dietary nutrients, including ME (kcal/bird per week), CP, TSAA, and Lys, all as grams per bird per week. A data set composed of 64 measurements taken from each strain were used for this analysis, where 44 data lines were used for model training, whereas the remaining 20 lines were used to test the created models. The results of this study revealed that it is possible to satisfactorily estimate the BW and carcass parts of the broiler chickens via their dietary nutrient intake. Through statistical criteria used to evaluate the performance of the SVR and NN models, the overall results demonstrate that the discussed models can be effective for accurate prediction of the body and carcass-related characteristics investigated here. However, the SVR method achieved better accuracy and generalization than the NN method. This indicates that the new data mining technique (SVR model) can be used as an alternative modeling tool for NN models. However, further reevaluation of this algorithm in the future is suggested.