CHANGES IN ULTRASONOGRAPHIC APPEARANCE OF ADRENAL GLANDS IN DOGS WITH PITUITARY-DEPENDENT HYPERADRENOCORTICISM TREATED WITH TRILOSTANE

Trilostane, a 3beta-hydroxysteroid dehydrogenase inhibitor, has been used successfully over the last few years for the treatment of canine pituitary-dependent hyperadrenocorticism. In a prospective study of 19 dogs with pituitary-dependent hyperadrenocorticism, the adrenal glands were measured before and at least 6 months after initiation of trilostane therapy. Right adrenal gland length and caudal pole thickness and left adrenal gland caudal pole thickness increased significantly (p < or = 0.05); there was no significant change in left adrenal gland length. Enlargement of adrenal glands during trilostane therapy may occur as a result of suppression of the negative feedback mechanism affecting cortisol production.     

Somaclonal variation as a tool for crop improvement

Summary Somaclonal variation is a tool that can be used by plant breeders. The review examines where this tool can be applied most effectively and the factors that limit or improve its chances of success. The main factors that influence the variation generated from tissue culture are (1) the degree of departure from organised growth, (2) the genotype, (3) growth regulators and (4) tissue source. Despite an increasing understanding of how these factors work it is still not possible to predict the outcome of a somaclonal breeding programme. New varieties have been produced by somaclonal variation, but in a large number of cases improved variants have not been selected because (1) the variation was all negative, (2) positive changes were also altered in negative ways, (3) the changes were not novel, or (4) the changes were not stable after selfing or crossing. Somaclonal variation is cheaper than other methods of genetic manipulation. At the present time, it is also more universally applicable and does not require containment procedures. It has been most successful in crops with limited genetic systems and/or narrow genetic bases, where it can provide a rapid source of variability for crop improvement.     

Implications of the number of years assessment on recommendation of common bean cultivars

In the common bean crop in Brazil, the requirement of the value for cultivation and use trials is that these experiments must be conducted over two years in three locations per region. Information in regard to the necessary number of years to ensure precision in cultivar recommendation and the influence of evaluated years in the estimation of the GE interaction are still scarce. Using grain yield of five check varieties assessed over 11 years in three sowing seasons per year, the aims of this study are as follows: to measure the relative contribution of the GE interaction, evaluating the implication of the number of years in the estimates of the GE interaction, and infer how many years are needed to ensure precision in cultivar recommendation. For instances, analysis of variance was carried out involving all environments and also combinations of years. The results showed that the GE interaction was greater than all other cross‐effects involving lines. The use of at least two years allows good coincidence in cultivar recommendation compared to the whole period. Increasing the evaluation time is a good strategy, especially when it is difficult to grow three different sowing seasons.     

Effect of some phenolic compounds and beverages on pepsin activity during simulated gastric digestion

The effect of some polyphenols (resveratrol, catechin, epigallocatechin-3-gallate, and quercetin) and beverages (red wine and green tea) on the enzymatic activity of pepsin during the digestion of three different substrates (pork meat, insoluble azocasein, and denatured hemoglobin) has been investigated. The tested polyphenols and beverages increase the initial velocity of the reaction, and the activating effect is concentration dependent. The order of effectiveness of polyphenols in increasing the initial velocity of the reaction is resveratrol > or = quercetin > epigallocatechin-3-gallate > catechin. The kinetic data obtained with soluble denatured hemoglobin show that the K(m) for the substrate is not changed, whereas the V(max) of the reaction is increased. Pepsin activity follows a simple Michaelis-Menten kinetic suggesting that k(3) is increased by polyphenols. To the authors' knowledge, the present study is the first demonstration that some polyphenols and related beverages are able to enhance the enzymatic activity of pepsin.     

Suitability of soil microbial parameters as indicators of heavy metal pollution

Several microbial parameters (microbial biomass, respiration, dehydrogenase, phosphatase, sulphatase, glucosidase, protease and urease activities) were measured in soils from five sites located in urban green areas close to roads differing in traffic density. Our aims were to evaluate the suitability of such parameters as field biomarkers of stress induced by heavy metal pollution, and to compare results obtained by single microbial parameters with results given by an index expressing the average microbial (AME) response of the microbial community. Data showed that all parameters were significantly reduced in the sites characterized by the highest load of metals in soil. Dehydrogenase, sulphatase, glucosidase activities and respiration, declined exponentially with increasing metal concentration, whereas phosphatase activity and AME decreased following a sigmoidal type relationship. In contrast, protease, urease and microbial biomass were not significantly correlated with soil metal concentration. Microbial parameters differed both in sensitivity to critical metal concentrations and in the rate of decline at increasing metal loads in soil. Due to the complex interplay of chemical, physical and biological factors which influence microbial activities and biomass, the proposed index (AME) appeared more suitable than single microbial parameters for a biomonitoring study of this type.     

Extraction of bacteria from soil: Efficiency of shaking or ultrasonication as indicated by direct counts and autoradiography

Blending, shaking with a mechanical wrist-action shaker or ultrasonication were compared for removing bacteria from a sandy soil and a silt loam soil. Bacteria were counted microscopically after staining with acridine orange. There was no significant difference in the numbers of bacteria released from the sandy soil by the different treatments but ultrasonication extracted more bacteria from the silt loam. Highest recoveries of bacteria were obtained with a combination of Tris buffer as extractant, and 25% Ringer's solution as diluent. Ultrasonication of an irradiated sandy soil containing added Bacillus cereus removed 97% of the bacteria from the sand grains, but lysed some cells. Members of the indigenous soil population were more firmly held by the soil than added bacteria. Optimum conditions for recovering soil bacteria by ultrasonication were either 10.5 μm for 30s or 5 μm for 2 min. With the natural population, the numbers of bacteria and the proportion of metabolizing bacteria increased a little after ultrasonication as shown by labelling cells with ³H-glucose and detecting uptake by autoradiography. However, three isolates of bacteria tested showed varying amounts of injury after ultrasonication, with 5 μm for 2 min causing more damage than 10.5 μm for 30s. Ultrasonication was a more efficient means of extracting the natural bacterial population of soil than shaking but the time and amplitude must be adjusted to avoid injury to cultured bacterial cells.     

Extrusion conditions affect chemical composition and in vitro digestion of select food ingredients

An experiment was conducted to determine the effects of extrusion conditions on chemical composition and in vitro hydrolytic and fermentative digestion of barley grits, cornmeal, oat bran, soybean flour, soybean hulls, and wheat bran. Extrusion conditions altered crude protein, fiber, and starch concentrations of ingredients. Organic matter disappearance (OMD) increased for extruded versus unprocessed samples of barley grits, cornmeal, and soybean flour that had been hydrolytically digested. After 8 h of fermentative digestion, OMD decreased as extrusion conditions intensified for barley grits and cornmeal but increased for oat bran, soybean hulls, and wheat bran. Total short-chain fatty acid production decreased as extrusion conditions intensified for barley grits, soybean hulls, and soybean flour. These data suggest that the effects of extrusion conditions on ingredient composition and digestion are influenced by the unique chemical characteristics of individual substrates.