Developmental studies on the Sigma and Delta-1 glutathione transferases of Lucilia cuprina

The glutathione transferases (GSTs) are a large group of enzymes having both detoxication roles and specialist metabolic functions. The present work represents an initial approach to identifying some of these roles by examining the variation of specific members of the family under differing conditions. The GSTs from Lucilia cuprina have been partially purified, members of two families being isolated, by the use of glutathione immobilised on epichlorhydrin-activated Sepharose 6B. The GSTs were separated by 2D SDS-PAGE and characterised by MALDI-TOF analysis of tryptic peptides. The mass fragments were then matched against the corresponding Drosophila melanogaster and Musca domestica sequences. GSTs were identified as coming from only the Sigma and Delta classes. The multiple Delta zones appear all to be derived from the Lucilia GSTD1 isoform. The distribution of these GST proteins has been studied during different developmental stages of the insect. Delta isoforms were present in all developmental stages of L. cuprina. The Sigma GST was not detectable in the egg, was just detectable in the larval and pupal stages and was the major GST isolated in the adult. Sigma and Delta isoforms were both found in all body segments of the insect. Both isoforms appear to undergo extensive post-translational modification. Activities of the two types of protein with model substrates have been determined.     

In vivo assessment of antidiabetic and antioxidative activity of natural phytochemical isolated from fruit-pulp of Eugenia jambolana in streptozotocin-induced diabetic rats

Objectives: Eugenia jambolana (E. jambolana) is well known for its antidiabetic potential. The aim of the present study was to investigate the antidiabetic and antioxidative effect of an active compound (FIIc) isolated from fruit-pulp of E. jambolana in streptozotocin (45?mg/kg body weight)-induced diabetic rats.

Methods: FIIc was isolated from the crude aqueous extract of fruit-pulp by ion-exchange column chromatography and high-performance column chromatography. Detailed UV, NMR, and IR spectra suggested that FIIc is α-hydroxy succinamic acid. FIIc was orally administered to diabetic rats at a dose of 10, 15, and 20?mg/kg body weight (mg/kg bwt.) to determine its effective dose. Thereafter, effective dose was administered to 8 weeks to determine its antidiabetic and antioxidative activity by estimation of glycemic index, lipid profile, key enzymes of carbohydrate metabolism, and oxidative stress parameters.

Results: Administration of 15?mg/kg dose daily for 8 weeks led to significant (P?P?Discussion: The results demonstrate that FIIc possesses significant antidiabetic and antioxidative activity.     

The glass transition temperatures of amorphous trehalose-water mixtures and the mobility of water: an experimental and in silico study

Isothermal-isobaric molecular dynamics simulations are used to calculate the specific volume of models of trehalose and three amorphous trehalose-water mixtures (2.9%, 4.5% and 5.3% (w/w) water, respectively) as a function of temperature. Plots of specific volume versus temperature exhibit a characteristic change in slope when the amorphous systems change from the glassy to the rubbery state and the intersection of the two regression lines provides an estimate of the glass transition temperature T(g). A comparison of the calculated and experimental T(g) values, as obtained from differential scanning calorimetry, shows that despite the predicted values being systematically higher (about 21-26K), the trend and the incremental differences between the T(g) values have been computed correctly: T(g)(5.3%(w/w))相似文献