Antioxidant enzymes and GST activity in natural populations of Holandriana holandrii from the Bosna River

Specimens of the freshwater snail Holandriana holandrii affected by different levels of contamination were collected from 3 sites within the Bosna River Basin, i.e. Visoko, Doboj, and Modrica. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST) were investigated in order to understand their variation with respect to the pollution status of the sampling locations. The results revealed a significant increase in CAT, GPx, and GST activities in the snails collected from Modrica, suggesting that the animals at this location are exposed to a higher level of oxidative stress as compared to those from Visoko and Doboj. On the other hand, increased SOD activity measured in specimens from Visoko was indicative of the presence of increased levels of superoxide anion radical. No snails from any location were significantly exposed to organic pollution, since its concentration in the whole body homogenates was below the limit of detection. Our findings show that changes in antioxidant enzymes and GST activity can be used as parameters in environmental monitoring programs

The effects of wild-type and mutant SOD1 on smooth muscle contraction

In this work we compared the mutated liver copper zinc-containing superoxide dismutase (SOD1) protein G93A of the transgenic rat model of familial amyotrophic lateral sclerosis (FALS), to wild-type (WT) rat SOD1. We examined their enzymatic activities and effects on isometric contractions of uteri of healthy virgin rats. G93A SOD1 showed a slightly higher activity than WT SOD1 and, in contrast to WT SOD1, G93A SOD1 did not induce smooth muscle relaxation. This result indicates that effects on smooth muscles are not related to SOD1 enzyme activity and suggest that heterodimers of G93A SOD1 form an ion-conducting pore that diminishes the relaxatory effects of SOD1. We propose that this type of pathogenic feedback affects neurons in FALS

Reversible Oxidation of Myometrial Voltage-Gated Potassium Channels with Hydrogen Peroxide

The uteri, spontaneously active or Ca2+ (6 mM) induced, were allowed to equilibrate, and to inhibit voltage-gated potassium () channels 1 mM 4-amino pyridine (4-AP) was applied for 15 min before adding H2O2 .  H2O2 was added cumulatively: 2 μM, 20 μM, 200 μM, 400 μM, and 3 mM. Average time for H2O2 concentrations (2, 20, 200, and 400) μM to reach its full effect was 15 min. H2O2 3 mM had a prolonged effect and therefore was left to act for 30 min. Two-way ANOVA showed significant differences in time dependency between spontaneous and Ca2+-induced rat uteri after applying 3 mM H2O2 (type of contraction, ), but not 400 μM H2O2 (). Our results indicate that H2O2 oxidises channel intracellular thiol groups and activates the channel, inducing relaxation. Cell antioxidative defence system quickly activates glutathione peroxidase (GSHPx) defence mechanism but not catalase (CAT) defence mechanism. Intracellular redox mechanisms repair the oxidised sites and again establish deactivation of channels, recuperating contractility. In conclusion, our results demonstrate that channels can be altered in a time-dependent manner by reversible redox-dependent intracellular alterations

Does cholesterol bound to haemoglobin affect the anti-oxidant enzyme defence system in human erythrocytes?

In a previous study, it was shown that the lipid fraction, which is occasionally observed in red blood cell hemolysates, represents cholesterol (Ch) associated with phospholipid firmly bound to haemoglobin (termed Hb-Ch). The current study was conducted to investigate whether Hb-Ch could affect the primary anti-oxidant enzyme defence system in human erythrocytes. Sixty healthy volunteers were used for the current study. Group 1 consisted of 28 subjects without or with a low level of Hb-Ch. Group 2 comprised 32 subjects with a considerably higher level of Hb-Ch. The activities of erythrocyte superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, as well as the content of methaemoglobin (metHb) were measured in both groups. The results indicated that the amount ofHb-Ch neither influenced the activities of the erythrocyte anti-oxidant enzymes nor altered the level of metHb. However, a higher amount ofHb-Ch changed the correlations in the part of the anti-oxidant defence system relating to glutathione, suggesting increased peroxidative pressure from plasma lipids. Group 2 also had significantly increased concentrations of total plasma Ch and triglycerides. Together, these facts are strong indications that the anti-oxidant defence system in human erythrocytes finely retunes its composition according to plasma oxidative demands

Apple pectin-derived oligosaccharides produce carbon dioxide radical anion in Fenton reaction and prevent growth of Escherichia coli and Staphylococcus aureus

Pectin is the main soluble fiber in apples or citruses. It may be fermented by gut microbiota to metabolites showing local intestinal and systemic effects. A wide range of beneficial effects of dietary pectin includes impacts on the redox milieu and microbiota profile. We prepared pectin-derived oligosaccharides (apple (APDO) and citrus) and polygalacturonic acid-derived oligosaccharides, using alkaline hydrolysis by hydrogen peroxide, and analyzed them by Foufier Transform Infrared spectrometry. Furthermore, we analyzed the effects of pectin derived oligosaccharides on hydroxyl radical (HO center dot)-generating Fenton reaction using electron paramagnetic resonance spin-trapping spectroscopy, and the effects on the growth of Escherichia coli and Staphylococcus minus in the presence of dietary-relevant HO center dot-generating system (iron + ascorbate). The oligosaccharides react with HO center dot radical to produce carbon dioxide radical anion (CO2 center dot (-)). A comparative analysis showed that APDO has the most prominent bacteriostatic effect. This might be at least partially related to the higher capacity of APDO to produce CO2 center dot (-), which specifically targets proteins and appears to have a longer lifetime and larger diffusion radius in biological systems compared to HO center dot.The peer-reviewed version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3043