Design of sediment oxygen demand (SOD) 'in-situ' measuring chamber and its application in several rivers

Sediment oxygen demand is defined as the rate of dissolved oxygen removal from the water column by the decomposition of organic materials in the bottom sediments. Accurate SOD rates are important, as they will allow for more precise permits specifications and therefore the degree or level of wastewater treatment needed. The "in situ" SOD chamber designed for the study was adapted from an earlier design by the USEPA (Hatcher, 1986). Two sets of chambers of differing sizes were fabricated and used to measure the SOD levels in several rivers and a small lake. These measurements could be used for the calibration and validation water quality models. Another applied usage of the SOD chamber was for the management of aquaculture ponds. The knowledge of the SOD levels at the bottom of the aquaculture ponds will allow for a more systematic pond-cleaning schedule

SOD activity of immobilized enzyme mimicking complexes

A binuclear, imidazolato-bridged, possible superoxide dismutase-mimicking complex (Cu(II)-diethylenetriamino-μ-imidazolato-Zn(II)-tris-aminoethylamine-triperchlorate) was prepared and immobilized on silica gel or among the layers of montmorillonite. The superoxide dismutase (SOD) activity of the complex before and after immobilization was studied by a SOD assay. It was found that the SOD activity of the host-free complex decreased somewhat when montmorillonite was the host, however, using silica gel as host it increased

Functional and structural mimics of superoxide dismutase enzymes

Superoxide dismutase (SOD) enzymes form important defence line in living organisms. Through a dismutation reaction they transform the highly reactive superoxide radical ion to oxygen and hydrogen peroxide. The latter compound is further transformed by catalase or peroxidase enzymes to water and oxygen. The overall structure of the enzymes and those of the active sites are largely known, thus, it has been revealed that in eukaryotes Cu(II) and Zn(II) ions act as cofactors and they are connected with an imidazolate bridge and this structural unit is coordinated with amino acids. In prokaryotes the SOD enzymes contain Mn(II) or Fe(II) or Ni(II) in their active centres. In order to learn about the working mechanism of SOD enzymes at the molecular level various structural mimics were prepared and their structural transformations during the dismutation reaction was followed. Gathering adequate amount of information allowed the preparation of functional mimics that are not necessarily copies of the active sites of the enzymes, nevertheless, display considerable SOD activity. Both functional and structural mimics are comprehensively dealt with in this review. Although enzymes may seem to be attractive catalysts for promoting real-life reactions effectively with high selectivity, they can seldom if ever be used under industrial conditions, i.e. at high temperatures and pressures. The SOD enzymes for promoting oxygen transfer reactions are not durable enough under these conditions either. The complexes mimicking SOD activities perform better in this respect, however, their reusabilities are limited, because of separation problems. A solution can be the immobilisation of these SOD mimicking complexes on solid or semi-solid supports. Even if the activity is not better then the support-free complexes, the catalyst can be filtered at the end of the reaction and can easily be recycled. Attempts for immobilisation are also comprehensively reviewed and immobilised complexes with surprisingly high SOD activities are reported as well. Full characterisation of these materials is given and rationalisation of their exceptionally high activities is offered

Structural Evidence for a Copper-Bound Carbonate Intermediate in the Peroxidase and Dismutase Activities of Superoxide Dismutase

Copper-zinc superoxide dismutase (SOD) is of fundamental importance to our understanding of oxidative damage. Its primary function is catalysing the dismutation of superoxide to O2 and H2O2. SOD also reacts with H2O2, leading to the formation of a strong copper-bound oxidant species that can either inactivate the enzyme or oxidise other substrates. In the presence of bicarbonate (or CO2) and H2O2, this peroxidase activity is enhanced and produces the carbonate radical. This freely diffusible reactive oxygen species is proposed as the agent for oxidation of large substrates that are too bulky to enter the active site. Here, we provide direct structural evidence, from a 2.15 Å resolution crystal structure, of (bi)carbonate captured at the active site of reduced SOD, consistent with the view that a bound carbonate intermediate could be formed, producing a diffusible carbonate radical upon reoxidation of copper. The bound carbonate blocks direct access of substrates to Cu(I), suggesting that an adjunct to the accepted mechanism of SOD catalysed dismutation of superoxide operates, with Cu(I) oxidation by superoxide being driven via a proton-coupled electron transfer mechanism involving the bound carbonate rather than the solvent. Carbonate is captured in a different site when SOD is oxidised, being located in the active site channel adjacent to the catalytically important Arg143. This is the probable route of diffusion from the active site following reoxidation of the copper. In this position, the carbonate is poised for re-entry into the active site and binding to the reduced copper. © 2012 Strange et al

PENGARUH PEMBERIAN SUPLEMENTASI SUPEROXIDE DISMUTASE (SOD) TERHADAP KADAR ALBUMIN SERUM PADA LANSIA

Background: Levels of serum albumin can be used as a predictor of morbidity and mortality in the elderly. Reduced serum albumin concentration can be caused by oxidative modification due to aging or insufficient protein intake. SOD as an enzymatic antioxidant might prevent oxidative stress so that albumin modification process can be inhibited. SOD supplementation was expected to increase serum albumin levels. Aim: Analyze the effect of SOD supplementation on elderly serum albumin level. Methods: This was a true experimental study with pre and post test control group design.. The study began with 31 elderly, resides in the “Pucang Gading Social Rehabilitation Unit”. They were divided into 2 groups. The control group (15 subjects), received placebo and exercise. The treatment group (16 subjects), received 250 IU SOD/day and exercise. Both treatments were done within 8 weeks, with twice a week exercise. Before and after treatment, levels of serum albumin were measured. Data normality was tested using Saphiro-wilk test. Data was analyzed by Paired-T-test if the distribution is normal, and using Wilcoxon test if the distribution is abnormal. Results: There were increases of serum albumin levels in both groups. Statistical test results showed a significant increase of serum albumin levels in the treatment group of 0.26 ± 0.33 mg/dL with p=0,007 (p0,05). Conclusion: 250 IU SOD/day supplementation for 8 weeks increase serum albumin levels in the elderly. Keywords: Albumin, elderly, aging, SO

Is there an interplay between adherence to mediterranean diet, antioxidant status, and vascular disease in atrial fibrillation patients?

Mediterranean Diet (Med-Diet) is associated with reduced incidence of vascular events (VEs) in atrial fibrillation (AF), but the mechanism accounting for its beneficial effect is only partially known. We hypothesized that Med-Diet may reduce VEs by improving antioxidant status, as assessed by glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). We performed a prospective cohort study investigating the relationship between adherence to Med-Diet, serum baseline GPx3 and SOD activities, and the occurrence of VEs in 690 AF patients. GPx3 activity was directly associated with Med-Diet score (B = 0.192, p < 0.001) and inversely with age (B = −0.124, p = 0.001), after adjustment for potential confounders; Med-Diet weakly affected SOD levels. During a mean follow-up of 46.1 ± 28.2 months, 89 VEs were recorded; patients with VEs had lower GPx3 levels compared with those without VEs (p = 0.002); and no differences regarding SOD activity were found. Multivariable Cox regression analysis showed that age (Hazard ratio [HR]:1.065, p < 0.001), logGPx3 (above median, HR: 0.629, p < 0.05), and Med-Diet score (HR: 0.547, p < 0.05) predicted VEs. Med-Diet favorably modulates antioxidant activity of GPx3 in AF, resulting in reduced VEs rate. We hypothesize that the modulation of GPx3 levels by Med-Diet could represent an additional nutritional strategy to prevent VEs in AF patients