Inhibition of thimet oligopeptidase by siRNA alters specific intracellular peptides and potentiates isoproterenol signal transduction

Mammalian cells have a large number of intracellular peptides that are generated by extralysosomal proteases. In this study, the enzymatic activity of thimet oligopeptidase (EP24.15) was inhibited in human embryonic kidney (HEK) 293 cells using a specific siRNA sequence. The semi-quantitative intracellular peptidome analyses of siRNA-transfected HEK293 cells shows that the levels of specific intracellular peptides are either increased or decreased upon EP24.15 inhibition. Decreased expression of EP24.15 was sufficient to potentiate luciferase gene reporter activation by isoproterenol (1-10 mu M). The protein kinase A inhibitor KT5720 (1 mu M) reduced the positive effect of the EP24.15 siRNA on isoproterenol signaling. Thus, EP24.15 inhibition by siRNA modulates the levels of specific intracellular peptides and isoproterenol signal transduction. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Nutritional composition of rice bran submitted to different stabilization procedures

In order to inactivate enzymatic deterioration, whole rice bran samples were subjected to two stabilization methods. Changes in nutritional value in terms of, concerning chemical composition, minerals and fatty acid content, were evaluated to supplement existing data and promote the utilization of rice bran in the human diet. The following homemade heat treatments were applied: roasting on a conventional stove or heating in a microwave oven. Based on the results, the different heating methods affected sample composition, since the levels of some nutrients of treated samples showed significant changes (p<0.05) compared to corresponding raw samples. The rice bran treated on a conventional stove produced products with lower moisture (5.14±0.10 g/100 g) and nutrients such as sodium 11.8%; palmitic acid 9.9% and stearic acid 8.1%. The microwave oven procedure resulted in better nutrient preservation, with slightly higher moisture content (6.28±0.10 g/100 g), and appears to be a practical and rapid tool for home heat stabilization of rice bran.