Alterations in the hepatic enzymes following experimental lead poisoning

An investigation on the influence of lead toxicity on some of the hepatic enzymes was studied in rats both after a shorter interval of 15 d and after longer intervals of 60 and 90 d. Three different doses of lead as 5, 10, and 50 mg/kg body wt were administered orally on every alternate day. Whereas significant inhibition of succinic dehydrogenase was seen following lead poisoning, the activity acid and alkaline phosphatase increased with lead intoxication. The histoarchitecture of the liver was grossly intact. Liver accumulated less lead compared to kidney at 60 and 90 d.     

Molecular and immunological characterization of the major outer membrane proteins of Brucella

Abstract Saccharomyces cerevisiae exponentially growing in basic or 0.7 M NaCl medium were isotopically labelled with ³⁵S-methionine, followed by protein separation and quantification by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) combined with computerised image analysis. The electrophoretic separation resolved about 650 proteins of which 13 displayed significant and at least 2-fold changes in rate of synthesis during saline growth. By sequencing of 2D-PAGE resolved proteins, one of the 8 induced spot, p42.9/5.5, was shown to correspond to the full length (containing the N-terminal extension) product of the GPD 1 gene encoding the cytoplasmic glycerol 3-phosphate dehydrogenase. The expression of the TDH 3 gene, glyceraldehyde 3-phosphate dehydrogenase, and the ENO 2 gene, enolase, decreased during growth in NaCl medium, declines hypothesised to have an impact on the flux to glycerol.     

Reaction profile of the last step in cytochrome P-450 catalysis revealed by studies of model complexes

 A series of oxoiron(IV) porphyrin cation radical complexes was investigated as compound I analogs of cytochrome P-450. Both the spectroscopic features and the reactivities of the complexes in oxygen atom transfer to olefins were examined as a function of only one variable, the axial ligand trans to the oxoiron(IV) bond. The results disclosed two important kinetic steps – electron transfer from olefin to oxoiron(IV) and intramolecular electron transfer from metal to porphyrin radical – which are affected differently by the axial ligands. The large kinetic barrier of the latter step in the reaction of olefins with the perchlorato-bound oxoiron(IV) porphyrin cation radical complex enabled the trapping of a reaction intermediate in which the metal, but not the porphyrin radical, is reduced. The first electron transfer step is probably followed by σ-bond formation, which readily accounts for formation of isomerized organic products at low temperatures. It is finally postulated that part of the enhanced oxygenation activities of cytochrome P-450 monooxygenases and chloroperoxidases is due to a lowering of the energy barrier for the second electron transfer step via participation of their redox-active cysteinate ligand. Received: 16 January 1997 / Accepted: 24 May 1997     

The energetics of middle-distance running

In order to assess the relative contribution of aerobic processes to running velocity (v), 27 male athletes were selected on the basis of their middle-distance performances over 800, 1500, 3000 or 5000 m, during the 1987 track season. To be selected for study, the average running velocity (v) corresponding to their performances had to be superior to 90% of the best French v of the season. Maximum O2 consumption (VO2max) and energy cost of running (C) had been measured within the 2 months preceding the track season, which, together with oxygen consumption at rest (VO2rest) allowed us to calculate the maximal v that could be sustained under aerobic conditions: vamax = (VO2max - VO2rest) x C-1. The treadmill running v corresponding to a blood lactate of 4 mmol.l-1 (vla4), was also calculated. In the whole group, C was significantly related to height (r = -0.43; P less than 0.03). Neither C nor VO2max (with, in this case, the exception of the 3000 m athletes) were correlated to v. On the other hand, vamax was significantly correlated to v over distances longer than 800 m. These v were also correlated to vla4. However vla4 occurred at 87.5% SD 3.3% of vamax, this relationship was interpreted as being an expression of the correlation between vamax and v. Calculation of vamax provided a useful means of analysing the performances. At the level of achievement studied, v sustained over 3000 m corresponded to vamax.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Importance of Amine-degrading Enzymes on the Biogenic Amine Degradation in Fermented Foods: A review

Biogenic amines (BAs) are a class of harmful compounds often be found in high protein foods, especially naturally fermented foods. BAs derive from free amino acid decarboxylation through microbial activities and can cause toxic effects (headache, heart palpitations, vomiting) on humans, depending on individual sensitivity. Indigenous amine-degrading strains or strains producing amine-degrading enzymes (ADEs) have drawn great attention since they play an important role in affecting BA accumulation, and enzymes/genes involved in the biosynthetic mechanisms. They also help maintain the sensory quality of the final products. Besides, due to ADEs’ harmless catalytic products, they can be further utilized in fermented foods and beverages to reduce BAs. This review describes in detail the mechanisms of BAs formation, as well as the diversity of ADEs able to degrade BAs in a model or real food systems. A deeper knowledge of this issue is crucial because ADEs’ activities are often associated with strains rather than species or genera. Moreover, this information can help to improve the selection and characterization of strains for further applications as starters or bioprotective cultures, to obtain high-quality foods with reduced BAs contents.     

Membrane—vanadium interaction: A toxicokinetic evaluation

Vanadium is an important trace metal widely distributed in environment. Interaction of vanadate with skeletal muscle sarcolemma and basement membrane has been focussed. Scatchard analysis indicated the presence of more than one binding site for vanadate. Vanadate inhibits sarcolemmal and intestinal brush border membrane enzymes in a non-competitive manner. Membrane-vanadium interaction may lead to several structural and functional changes. The binding of vanadium to basement membrane may have some protective role.     

Effects Ala54Thr polymorphism of FABP2 on obesity index and biochemical variable in response to a aerobic exercise training

The purpose of the current study was to investigate whether or not the FABP2 gene polymorphism modulated obesity indices, hemodynamic factor, blood lipid factor, and insulin resistance markers through 12-week aerobic exercise training in abdominal obesity group of Korean mid-life women. A total of 243 abdominally obese subjects of Korean mid-life women voluntarily participated in aerobic exercise training program for 12 weeks. Polymerase Chain Reaction with Restriction Fragment Length Polymorphism (PCR-RFLP) assay was used to assess the FABP2 genotype of the participants (117 of AA homozygotes, 100 of AT heterozygotes, 26 of TT homozygotes). Prior to the participation of the exercise training program, baseline obesity indices, hemodynamic factor, blood lipid factor, and insulin resistance markers were measured. All the measurements were replicated following the 12-week aerobic exercise training program, and then the following results were found. After 12-week aerobic exercise training program, wild type (Ala54Ala) and mutant type (Ala54Thr+Thr54Thr) significantly decreased weight (P > .001), BMI (P > .001), %bf (P > .001), waist circumference (P > .001), WHR (P > .001), muscle mass (wild type p < .022; mutant type P > .001), RHR (P > .001), viseceral adipose area (wild type p < .005; mutant type P > .001), subcutaneous area (P > .001), insulin (wild type p < .005; mutant type P > .001) and significantly increased VO2max (P > .001). And wild type significantly decresed NEFA (P > .05), glucose (P > .05), OGTT 120min glucose (P > .05) and significantly increased HDLC (p > .005). Mutant type significantly decreased SBP (P > .001), DBP (P > .01), TC (P > .01), LPL (P > .05), LDL (P > .001), HOMA index (P > .01). The result of the present study represents that regular aerobic exercise training may beneficially prevent obesity index, blood pressure, blood lipids and insulin resistance markers independent of FABP Ala54Thr wild type and mutant type.     

A temperature‐dependent conformational change of NADH oxidase from Thermus thermophilus HB8

Using molecular dynamics simulations and steady‐state fluorescence spectroscopy, we have identified a conformational change in the active site of a thermophilic flavoenzyme, NADH oxidase from Thermus thermophilus HB8 (NOX). The enzyme's far‐UV circular dichroism spectrum, intrinsic tryptophan fluorescence, and apparent molecular weight measured by dynamic light scattering varied little between 25 and 75°C. However, the fluorescence of the tightly bound FAD cofactor increased approximately fourfold over this temperature range. This effect appears not to be due to aggregation, unfolding, cofactor dissociation, or changes in quaternary structure. We therefore attribute the change in flavin fluorescence to a temperature‐dependent conformational change involving the NOX active site. Molecular dynamics simulations and the effects of mutating aromatic residues near the flavin suggest that the change in fluorescence results from a decrease in quenching by electron transfer from tyrosine 137 to the flavin. Proteins 2012. © 2011 Wiley Periodicals, Inc.     

Hymenolepis diminuta: Action of worm RNase against RNA

Hymenolepis diminuta possesses a tegumental ribonuclease (RNase) which hydrolyzes rat liver and degraded yeast RNA. Polyacrylamide gel electrophoresis and gel chromatography of rat liver RNA after incubation with intact worms demonstrated significant hydrolysis of the high molecular weight RNA fractions (28 S and 18 S), with the appearance of fractions of intermediate molecular weight (i.e., between 18 S and 4 S), as well as ethanol-soluble fractions. Hydrolysis of degraded yeast RNA (with a molecular weight of approximately 25,000) yielded a single ethanol-precipitable hydrolysis product, as well as ethanol-soluble hydrolysis products.