The influence of hypomagnesemia on erythrocyte antioxidant enzyme defence system in mice

The effect of magnesium deficiency on antioxidant defence system was studied in RBC of mice suffering from hypomagnesemia. The animals were kept for 8, 15 and 22 days on magnesium-deficient diet with consequent reduction of magnesium level in plasma by 38% at the first 8 days and by 64% after 22 days of experiment. The activities of the most important antioxidant enzymes, catalase, glutathione peroxidase, superoxide dismutase, glutathione reductase, glutahione S-transferase were assayed in hemolysates. The level of reduced glutathione in erythrocytes was measured as well. Apart from catalase, the activities of antioxidant enzymes were decreasing. The activity of superoxide dismutase decreased gradually during the experiment and on the 15th and 22nd day of experiment was significantly (P<0,05) lowered by 30 and 32% respectively. The catalase activity was increased on each point of the experiment with the peak value up to 149% on 15th day, and by 32% on 22nd day. Glutathione peroxidase activity was insignificantly reduced. The reduction of Glutatione reductase and Glutathione S-transferase activities by 24 and 21%, respectively, were observed after 8 days of the experiment with a further downward tendency. The reduced glutathione was significantly depleted after 8 days by 33% and was kept on that level in the course of the study. These findings support previous reports on the hypomagnesemia – induced alteration in endogenous enzyme antioxidant defences and glutathione redox cycle of mice.     

ESR evidence of superoxide radical dismutation by human ceruloplasmin

The formation of the paramagnetic complex between human ceruloplasmin and radiation produced superoxide radicals was observed by the ESR method at low temperatures. The disappearance of the complex without changes in the oxidation state of copper give the direct evidence that ceruloplasmin, the major antioxidant in serum, is able to dismutate superoxide radicals.     

Combined effect of X‐ray radiation and static magnetic fields on reactive oxygen species in rat lymphocytes in vitro

The aim of this study was to investigate the effect of static magnetic fields (SMF) on reactive oxygen species induced by X‐ray radiation. The experiments were performed on lymphocytes from male albino Wistar rats. After exposure to 3 Gy X‐ray radiation (with a dose rate of 560 mGy/min) the measurement of intracellular reactive oxygen species in lymphocytes, using a fluorescent probe, was done before exposure to the SMF, and after 15 min, 1 and 2 h of exposure to the SMF or a corresponding incubation time. For SMF exposure, 0 mT (50 µT magnetic field induction opposite to the geomagnetic field) and 5 mT fields were chosen. The trend of SMF effects for 0 mT was always opposite that of 5 mT. The first one decreased the rate of fluorescence change, while the latter one increased it. Bioelectromagnetics 34:333–336, 2013. © 2012 Wiley Periodicals, Inc.     

Application of carbon balance to submerged citric acid production by Aspergillus niger

Summary In an air-lift fermenter, the following production was obtained from 125 g sucrose in mineral medium at pH 2.5 : 15.76 g mycelium dry wt, 107.2 g citric acid anhydrous and 0.594 mol CO₂ within 138 h (run I) and 13.72 g mycelium dry wt, 114.28 g citric acid and 0.516 mol CO₂ within 144 h (run II). Initially, the carbon content of consumed sugar and products did not balance. At the end of fermentation, the carbon content of the products was 0.9%–5.5% higher than that of the consumed sugar. For the purpose of the calculations the carbon content in mycelium was accepted as 0.462.The work was a part of Project No 04.11 CPBP, topic No 2.24     

Wheat germ agglutinin binding sites on human urothelial cells of different grades of transformation

¹²⁵I-Wheat germ agglutinin (WGA) binding parameters of human urothelial cell lines of different grades of transformation (TGrll and TGrlll) were compared. The values of association constant (K_a) and the number of binding sites/cell for HCV29 (TGrll) cell line were about 3×10⁶M^–1 and over 4×10⁷, respectively. Two TGrlll cell lines, HCV29T and Hu549 revealed lower values for K_a, and considerably higher numbers of binding sites/cell (about 3×10⁸ and 2×10⁸, respectively). Binding of¹²⁵I-WGA to total cellular proteins resolved by SDS-PAGE and transferred to nitrocellulose showed multiple diffused bands in the range of 58–180 kDa. Some of these bands were characteristic for TGrll cells (124 kDa) or TGrlll cells (135 and 148 kDa).Abbreviations TGr transformation grade - WGA wheat germ agglutinin - sWGA succinylated wheat germ agglutinin - GlcNAc N-acetyl-d-glucosamine - BSA bovine serum albumin - SDS-PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis     

In vivo crosslinking of nuclear proteins to DNA by cis-diamminedichloroplatinum (II) in differentiating rat myoblasts

When cells are briefly exposed to cis-diamminedichloroplatinum (II) before lysis in high sodium dodecyl sulfate-urea solutions, the high molecular-weight nucleic acids pelleted by ultracentrifugation contain an increased level of bound proteins when compared to a similar fraction from untreated cells. Subsequent shearing of the pelleted DNA followed by treatment with DNase permits electrophoretic and immunoblot analysis of the crosslinked proteins. In the present study such experiments were carried out with reference to nuclear envelope pore complex proteins in the differentiating L8 rat skeletal muscle cells. The results show that (i) whereas the major lamin proteins crosslinked to DNA in both myoblast and myotubes, lamin B is crosslinked to a greater extent to DNA in myotubes; (ii) a 62-kDa lectin-binding glycoprotein is apparently situated differently with respect to DNA in myotube nuclei; and (iii) the crosslinking pattern of the nuclear matrix proteins to DNA is qualitatively similar in myoblast and myotubes. In addition, lamin C′, a modified form of lamin C, not observed in intact nonmuscle cells previously [[31.] J. Biol. Chem. 260, 1895–1900], exists as a native component of the nuclear lamina in rat skeletal myotubes but not in myoblasts. These results point to significant structural alterations in the proteins of the nuclear lamina-pore complex during myogenesis.     

Improvement in stability of an immobilized fungal laccase

Summary A laccase of the basidiomyceteTrametes versicolor was immobilized on porous glass beads that were activated with 3-aminopropyltriethoxysilane and glutaraldehyde. The support immobilized 100% of the enzyme, whereupon 90% of the original activity was retained. After immobilization, the enzyme was active in a wider pH and temperature range, and its heat stability and reuse were greatly improved compared to those of the free laccase. The immobilized enzyme was found reusable in treating different substrates, either recycled alone or in a sequential order.