Enzymatic extraction of beta-glucan from oat bran cereals and oat crackers and optimization of viscosity measurement

The viscosity of the soluble fibre, β-glucan, has been shown to influence its ability to lower serum cholesterol and postprandial blood glucose levels. The impact of various amylases, proteases and lipase on the solubility and resulting viscosity of β-glucan extracted from oat bran cereals with a range of β-glucan concentrations and molecular weights was investigated. Addition of enzymes increased the final viscosity of high molecular weight β-glucan in cereals by facilitating the release of β-glucan from the food matrix. For cereals with partially depolymerized β-glucan, the addition of digestive enzymes decreased the final viscosity by eliminating the contribution of starch and protein to viscosity. Final viscosity varied depending on enzyme combinations including pancreatin, salivary and microbial α-amylases, microbial protease, porcine protease, trypsin and α-chymotrypsin. Addition of lipase did not significantly affect viscosity or solubility of β-glucan extracted from oat crackers. Addition of lichenase showed that β-glucan was the major contributor of viscosity to the system, with negligible interference from other components. The viscosity of the optimized protocol was compared to physiological results previously obtained. The viscosity of β-glucan extracted with pancreatin plus microbial α-amylase (pH 6.9) was predictive of LDL-cholesterol reduction (R² = 0.847) and glycemic response (R² = 0.883).     

Clarification of teat stenoses in cattle by ultrasound

Ultrasonography and radiography were used as an adjunct to clinical examination in the evaluation of 73 obstructed teats in 63 dairy cows. The images obtained with a 3.5 MHz and a 5 MHz linear array transducer were compared with radiographs and correlated with findings obtained at surgery. Ultrasonography and radiography allowed a correct assessment of the lesions in 68 respectively 58 teats. In five cases the obstructive lesions in the teat canal were not clearly discernible when ultrasonography was used. Radiography was the method of choice for the evaluation of the teat canal and small mucosal folds in the milk cistern. Ultrasonography was the method of choice for the detection of obstructive lesions at the base of the teat; all 14 of these cases were assessed correctly using ultrasonography versus three of 14 when radiography was used. Ultrasonography is a useful tool for the practitioner to evaluate obstructive teat lesions.     

Evidence for antibody-catalyzed ozone formation in bacterial killing and inflammation

Recently, we showed that antibodies catalyze the generation of hydrogen peroxide (H2O2) from singlet molecular oxygen (1O2*) and water. Here, we show that this process can lead to efficient killing of bacteria, regardless of the antigen specificity of the antibody. H2O2 production by antibodies alone was found to be not sufficient for bacterial killing. Our studies suggested that the antibody-catalyzed water-oxidation pathway produced an additional molecular species with a chemical signature similar to that of ozone. This species is also generated during the oxidative burst of activated human neutrophils and during inflammation. These observations suggest that alternative pathways may exist for biological killing of bacteria that are mediated by potent oxidants previously unknown to biology.     

Effect of Inoculation with Plant Growth-Promoting Bacteria on Growth and Copper Uptake by Sunflowers

The effect of plant growth-promoting bacteria inoculation on Helianthus annuus growth and copper (Cu) uptake was investigated. For this, the strains CC22, CC24, CC30, and CC33 previously isolated from heavy metal- and hydrocarbon-polluted soil were selected for study. These strains were characterized on the basis of their 16S rDNA sequences and identified as Pseudomonas putida CC22, Enterobacter sakazakii CC24, Acinetobacter sp. CC30, and Acinetobacter sp. CC33. Strains were able to synthesize indole, solubilize phosphorus, and produce siderophores in vitro, which are proper characteristics of plant growth-promoting (PGP) bacteria. Bacteria were also able to bioaccumulate Cu(II), and most of them could use aromatic hydrocarbons as a sole carbon source. Furthermore, Acinetobacter sp. CC33 exhibited the greatest extent of Cu(II) accumulation, and CC30 the widest range for degrading hydrocarbons. Acinetobacter sp. CC30 was selected for pot experiments on the basis of its plant growth-promoting properties. Inoculation with CC30 significantly increased the plant biomass (dry weight and length of root and shoot) and improved the photosynthetic pigment content in non- and Cu-contaminated soil (p < 0.05). Additionally, plant Cu uptake was improved by CC30 inoculation showing a significantly enhanced root Cu content (p < 0.05). Our findings evidenced that the strain CC30 protected the plant against the deleterious effect of Cu contamination and improved the Cu extraction by plant, hence concluding that its inoculation represents an alternative to improve phytoremediation process of heavy metals, particularly Cu, in contaminated environments.     

Glycemic Response to Extruded Oat Bran Cereals Processed to Vary in Molecular Weight

Oat β‐glucan enriched extruded cereals with molecular weights (MWs) ranging from 2,180,000 to 326,000 were produced. Test meals composed of 31 g of available carbohydrate, 8.3–8.7 grams of β‐glucan, and milk were administered to subjects and their postprandial blood glucose levels monitored for 2 hr. White bread plus milk and a control wheat bran cereal plus milk were administered, and white bread alone served as a reference food for estimation of glycemic index (GI) of the cereals, after adjusting for the effect of adding milk to white bread. Both oat bran and wheat bran cereals significantly reduced peak blood glucose rise (PBGR) and area under the curve (AUC) versus white bread alone or white bread plus milk. There was a significant inverse relationship between AUC and log₁₀[weight average MW] (r² = 0.96, P = 0.0192). There was a significant inverse relationship between PBGR and log₁₀[viscosity] of in vitro extracts from all cereals, including the wheat control (r² = 0.96, P = 0.0031). However, no significant differences in glycemic responses among the oat bran cereals were found with pairwise comparisons. All cereals were low GI (<55) and were significantly lower than white bread alone or white bread plus milk. Among the oat bran cereals, palatability was positively correlated with MW (r² = 0.98, P = 0.0110).