Cadmium effects on growth and antioxidant enzymes activities in Miscanthus sinensis

Plants of Miscanthus sinensis (cv. Giganteus) were grown in hydroponics for three months in nutrient solution with 0, 2.2, 4.4 and 6.6 μM CdNO₃. Growth parameters, catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities were analysed in leaves and roots collected after 1-and 3-month exposure. Dry biomass of all miscanthus organs was affected by Cd concentration both after 1-and 3-month exposure. No visible symptoms of Cd toxicity were observed in shoots and rhizomes of plants grown in presence of Cd. In contrast, roots became shorter and thicker and the whole root system more dense and compact already after one month of treatment with 6.6 μM Cd. The lower Cd concentration increased the enzymes activities after 3 months in leaves and only after 1-month in roots, while a decrease in activity was observed at higher Cd concentrations.     

Relation between oxidative stress markers and antioxidant endogenous defences during exhaustive exercise

Hydrogen peroxide (H₂O₂) could induce oxidative damage at long distance from its generation site and it is also an important signalling molecule that induces some genes related to oxidative stress. Our objective was to study the plasma and blood cells capability to detoxify H₂O₂ after intense exercise and its correlation with oxidative damage. Blood samples were taken from nine professional cycling, participating in a mountain stage, under basal conditions and 3 h after the competition. Catalase and glutathione peroxidase activities decreased (40 and 50% respectively) in neutrophils after the cycling stage, while glutathione peroxidase increased (87%) in lymphocytes. Catalase protein levels and catalase specific activity maintained basal values after the stage in plasma. Catalase protein levels decreased (48%) in neutrophils and its specific activity increased up to plasma values after exercise. Myeloperoxidase (MPO) increased (39%) in neutrophils after the cycling stage. Exercise-induced hemolysis and lymphopenia inversely correlated with cellular markers of oxidative stress. Plasma malondialdehyde (MDA) directly correlated with neutrophil MPO activity and erythrocytes MDA. Intense exercise induces oxidative damage in blood cells as erythrocytes and lymphocytes, but not in neutrophils.     

Relation between oxidative stress markers and antioxidant endogenous defences during exhaustive exercise

Hydrogen peroxide (H₂O₂) could induce oxidative damage at long distance from its generation site and it is also an important signalling molecule that induces some genes related to oxidative stress. Our objective was to study the plasma and blood cells capability to detoxify H₂O₂ after intense exercise and its correlation with oxidative damage. Blood samples were taken from nine professional cycling, participating in a mountain stage, under basal conditions and 3 h after the competition. Catalase and glutathione peroxidase activities decreased (40 and 50% respectively) in neutrophils after the cycling stage, while glutathione peroxidase increased (87%) in lymphocytes. Catalase protein levels and catalase specific activity maintained basal values after the stage in plasma. Catalase protein levels decreased (48%) in neutrophils and its specific activity increased up to plasma values after exercise. Myeloperoxidase (MPO) increased (39%) in neutrophils after the cycling stage. Exercise-induced hemolysis and lymphopenia inversely correlated with cellular markers of oxidative stress. Plasma malondialdehyde (MDA) directly correlated with neutrophil MPO activity and erythrocytes MDA. Intense exercise induces oxidative damage in blood cells as erythrocytes and lymphocytes, but not in neutrophils.     

Phytoextraction of heavy metals by Sesuvium portulacastrum l. a salt marsh halophyte from tannery effluent

The present study investigated the sources for remediation of heavy metals and salts from tannery effluent using salt marsh halophyte Sesuvium portulacastrum. From the results observed, in tannery effluent treated soil from 1 kg dry weight of plant sample, Sesuvium portulacastrum accumulated 49.82 mg Cr, 22.10 mg Cd, 35.10 mg Cu and 70.10 mg Zn and from 1 g dry weight of the plant sample, 246.21 mg Na Cl. Cultivation of Sesuvium portulacastrum significantly reduced the EC, pH and SAR levels in tannery effluent and salt treated soil and correspondingly increased in plant sample after 125 days of cultivation. In conclusion, Sesuvium portulacastrum was an efficient in accumulating heavy metals such as Chromium, Cadmium, Copper and Zinc, sodium and chloride maximum through its leaves when compared to stem and root. The finding of these bioacccumulation studies indicates that Sesuvium portulacastrum could be used for phytoremediation of tannery effluent contaminated field.     

Decontamination of coal mine effluent generated at the Rajrappa coal mine using phytoremediation technology

Toxicity of the effluent generated at the Rajrappa coal mine complex under the Central Coalfields Limited (CCL, a subsidiary of Coal India Limited) in Jharkhand, India was investigated. The concentrations (mg L^?1) of all the toxic metals (Fe, Mn, Ni, Zn, Cu, Pb, Cr, and Cd) in the coal mine effluent were above the safe limit suggested by the Environmental Protection Agency (EPA 2003). Among these, Fe showed the highest concentration (18.21 ± 3.865), while Cr had the lowest effluent concentration (0.15 ± 0.014). Efforts were also made to detoxify the effluent using two species of aquatic macrophytes namely “‘Salvinia molesta and Pistia stratiotes.” After 10 days of phytoremediation, S. molesta removed Pb (96.96%) > Ni (97.01%) > Cu (96.77%) > Zn (96.38%) > Mn (96.22%) > Fe (94.12%) > Cr (92.85%) > Cd (80.99%), and P. stratiotes removed Pb (96.21%) > Fe (94.34%) > Ni (92.53%) > Mn (85.24%) > Zn (79.51%) > Cr (78.57%) > Cu (74.19%) > Cd (72.72%). The impact of coal mine exposure on chlorophyll content showed a significant decrease of 42.49% and 24.54% from control values in S. molesta and P. stratiotes, respectively, perhaps due to the damage inflicted by the toxic metals, leading to the decay of plant tissues.     

Biogas-plant effluent as an organic fertiliser in fish polyculture

Biogas-plant effluent collected from a KVIC model biogas-plant fed on cattle waste was utilised in fish polyculture. Biogas-plant effluent was applied at 0·15% concentration at 3-day intervals. The growth rate of Labeo rohita was 4·52 ±0 ·75 g fish⁻¹ day⁻¹, of Cirrhina mrigala 3·36 ± 0·48 g fish⁻ day⁻¹ and of Cyprinus carpio was 1·82 ± 0·41 g fish⁻¹ day⁻¹. Total fish production was 13·44 ± 0·77 kg 0·002 ha⁻¹ year⁻¹ (6653 kg ha⁻¹ year⁻¹) without any supplementary fish-feed.     

Does the grasshopper Chorthippus brunneus adapt to metal polluted habitats? A study of glutathione‐dependent enzymes in grasshopper nymphs

Glutathione contents and activity of glutathione-dependent enzymes in the body of insects inhabiting polluted areas depend on toxin kind, concentration and exposure time. Enzymatic response may be modified by gender, age, developmental stage and state of nutrition. Also, chronic exposure to metals in the environment may cause the selection of individuals resistant to some environmental toxins. To assess the degree of adaptation of Chorthippus brunneus to metal-polluted habitats, we measured glutathione contents and the activity of selected glutathione-dependent enzymes in the offspring of aging mothers which differed in time and intensity of exposure to metals in their habitats. We tested whether differences represent temporal shifts in tolerance range or were genetically preserved and inherited by future generations. We investigated insects from three populations. Two live in heavily metal-burdened areas, exposed to metals for 170 (Szopienice) or 50 years (Olkusz) and the third inhabits an unpolluted reference site (Pilica). The most important findings were age-by-site interactions for all biochemical analyses. Nymphs from Szopienice had lower glutathione contents and lower glutathione-dependent enzyme activity in comparison with nymphs from the reference site. This was especially distinct in nymphs hatched from eggs laid by young females. The offspring of aging females from Olkusz, in terms of glutathione contents and glutathione reductase activities, revealed similar patterns to those from the reference site. For the remaining parameters, enzyme activity patterns in nymphs from Olkusz were similar to those of nymphs from Szopienice.     

Effect of lead exposure on liver lipid peroxidative and antioxidant defense systems of protein-undernourished rats

The effect of the liver mitogen, lead nitrate [Pb(NO₃)₂], on protein-undernutrition-induced increased lipid peroxidation and reduced antioxidants levels was investigated in rats. Animals were divided into four groups: A, B, C, and D of five animals each. Animals in groups C and D were placed on a low-protein diet (5% casein) and animals in groups A and B were maintained on a normal diet (16% casein) for 14 wk and fed ad libitum. Animals in groups B and D were each given a single intravenous injection of Pb(NO₃)₂ (100 μmol/kg body weight) 72 h before sacrifice. The results confirm that protein undernutrition (PU) induced an increase in lipid peroxidation with concomitant reductions in catalase (CAT) activity, glutathione (GSH) level, and superoxide dismutase (SOD) activity. Lead (Pb) treatment, however, provoked increased lipid peroxidation, CAT activity, and GSH level but resulted in reduced SOD activity in both normal and PU-rats. These results suggest that Pb exacerbates liver lipid peroxidation in PU rats and suggests the involvement of free radicals in the pathogenesis of Pb poisoning. In addition, the results show that Pb affects well-fed and PU rats in similar ways but that the CAT activity of PU rats is more sensitive to the effect of Pb than that of normal rats.     

The antioxidant defense system of isolated guinea pig Leydig cells

Utilization of highly enriched preparations of steroidogenic Leydig cells have proven invaluable for studying the direct effects of various hormones and agents on Leydig cell functionin vitro. However, recent work indicates that isolated Leydig cells are often subjected to oxygen (O₂) toxicity when cultured at ambient (19%) oxygen concentrations. Because intracellular antioxidants play an important role in protecting cells against oxygen toxicity, we have investigated the intracellular antioxidant defense system of isolated Leydig cells. The cellular levels of several antioxidants including catalase, glucose-6-phosphate dehydrogenase (G-6-PDH), superoxide dismutase (SOD) of the Cu/Zn & Mn variety, glutathione peroxidase, glutathione reductase and total glutathione were quantitated using enriched populations of Leydig cells isolated from adult male guinea pig testes. Compared to whole testicular homogenates, Leydig cells contained significantly (P<0.01) less G-6-PDH, total SOD, glutathione reductase and total glutathione, but significantly (P<0.001) more glutathione peroxidase. Compared to hepatic values previously reported in the guinea pig, Leydig cells contain nearly 400 times less catalase, about 14 times less glutathione peroxidase and almost 11 times less glutathione reductase. Since G-6-PDH and glutathione reductase are both necessary to regenerate reduced gluthathione (GSH) which couples with glutathione peroxidase to breakdown hydrogen peroxide (H₂O₂) under normal conditions, it is plausible that the oxygen toxicity observed in isolated Leydig cells is due to the intracellular accumulation of H₂O₂. Using the dichlorofluorescin diacetate (DCF-DA) assay, we found that Leydig cells incubated in the presence of 19% O₂ produced significantly (P<0.001) higher levels of H₂O₂ with time in culture compared to Leydig cells maintained at 3% O₂. These results support the hypothesis that the increased susceptibility of isolated Leydig cells to oxygen toxicity may be due, in part, to decreased amounts of certain antioxidant defenses and an increased production of the reactive oxygen species H₂O₂.     

Effect of acute vs chronic H2O2-induced oxidative stress on antioxidant enzyme activities

H₂O₂ can freely crosses membranes and in the presence of Fe²⁺ (or Cu⁺) it is prone to participate in Fenton reaction. This study evaluated the concentration and time-dependent effects of H₂O₂-induced oxidative stress on MnSOD, Se:GPx and catalase and on aconitase. Acute and chronic H₂O₂ treatments were able to induce oxidative stress in HeLa cells as they significantly decreased aconitase activity and also caused a very significant decrease on antioxidant enzyme activities. The inhibition of enzyme activities was time- and concentration-dependent. Chronic treatment with 5 µM H₂O₂/h after 24 h was able to decrease all enzyme activities almost at the same level as the acute treatment. Acute and chronic treatments on antioxidant enzyme activities were prevented by cell treatment with ascorbic acid or N-acetylcysteine. These results indicate that antioxidant enzymes can also be affected by the same ROS they produce or neutralize if the time of exposure is long enough.     

Probucol treatment reverses antioxidant and functional deficit in diabetic cardiomyopathy

Earlier we reported that probucol treatment subsequent to the induction of diabetes can prevent diabetes-associated changes in myocardial antioxidants as well as function at 8 weeks. In this study, we examined the efficacy of probucol in the reversal of diabetes induced myocardial changes. Rats were made diabetic with a single injection of streptozotocin (65 mg/kg, i.v.). After 4 weeks of induction of diabetes, a group of animals was treated on alternate days with probucol (10 mg/kg i.p.), a known lipid lowering agent with antioxidant properties. At 8 weeks, there was a significant drop in the left ventricle (LVSP) and aortic systolic pressures (ASP) in the diabetic group. Hearts from these animals showed an increase in the thiobarbituric acid reacting substances (TBARS), indicating increased lipid peroxidation. This was accompanied by a decrease in the myocardial antioxidant enzymes activities, superoxide dismutase (SOD) and glutathione peroxidase (GSHPx). Myocardial catalase activity in the diabetic group was higher. In the diabetic + probucol group both LVSP and ASP showed significant recovery. This was also accompanied by an improvement in SOD and GSHPx activities and there was further increase in the catalase activity. Levels of the TBARS were decreased in this group. These data provide evidence that diabetic cardiomyopathy is associated with an antioxidant deficit which can be reversed with probucol treatment. Improved cardiac function with probucol may be due to the recovery of antioxidants in the heart.     

Erythrocyte glutathione transferase: a non-antibody biomarker for systemic sclerosis,which correlates with severity and activity of the disease

Erythrocyte glutathione transferase (e-GST) is a detoxifying enzyme hyper-expressed in nephropathic patients and used recently as a biomarker for blood toxicity. Systemic sclerosis (SSc) is characterized by endothelial dysfunction and fibrosis of the skin and internal organs. Renal involvement is frequent in SSc patients. Here we show that e-GST is hyper-expressed in SSc patients (n=102) and correlates (R²=0.49, P<0.0001) with the Medsger DSS and DAI Valentini indices that quantify the severity and activity of this disease. Interestingly, e-GST does not correlate with the impairment of kidney or other specific organs taken separately. e-GST hyper-expression seems to be linked to the presence of a factor (i.e., toxin) that triggers the autoimmune disease, and not to the damage of specific organs or to oxidative stress. e-GST may be proposed as an innovative non-antibody biomarker for SSc useful to check the progress of this disease and the efficiency of new therapeutic strategies.     

Effect of water-borne zinc on osmoregulation in the freshwater amphipod Gammarus pulex (L.) from populations that differ in their sensitivity to metal stress

1. Although there is some evidence that exposure to heavy metals can disrupt osmoregulation in crustaceans, most studies have been carried out on relatively pollution-tolerant, marine or estuarine species. Consequently the effects of water-borne zinc (Zn) on osmoregulation by the freshwater amphipod, Gammarus pulex (L.), from two populations that differ in their heavy metal sensitivity, have been compared.
2. 'Clean' site animals (Clowne, Derbyshire) exhibited a marked haemoconcentration (after 4 days at 37·0 μmol Zn l^–1, 5 days at 18·2 μmol Zn l^–1) shown by an increase in haemolymph osmotic pressure (OP_h) and [Na⁺] and [K⁺]. However, after 5 days at 37·0 μmol Zn l^–1, haemolymph of survivors exhibited an OP_h significantly less than controls. 'Contaminated' site animals showed a reduction in OP_h (but not ions) only after 5 days at 76·2 μmol Zn l^–1.
3. There were differences in the threshold and nature of osmoregulatory response to Zn between animals from 'clean' and 'contaminated' sites, but only at concentrations in excess of those (a) known to affect growth and reproduction in 'clean' site animals and (b) occurring at the 'contaminated' site. Clearly population differences in physiological capacity and tolerance do exist but their ecological significance is unclear.     

The effects of diazinon on lipid peroxidation and antioxidant enzymes in rat heart and ameliorating role of vitamin E and vitamin C

Diazinon is one of the most widely used organophosphate insecticides (OPIs) in agriculture and public health programs. Reactive oxygen species (ROS) caused by OPIs may be involved in the toxicity of various pesticides. The aim of this study was to investigate how diazinon affects lipid peroxidation (LPO) and the antioxidant defense system in vivo and the possible ameliorating role of vitamins E and C. For this purpose, experiments were done to study the effects of DI on LPO and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in adult rat heart. Experimental groups were: (1) control group, (2) diazinon treated (DI) group, (3) DI+vitamins E and C-treated (DI+Vit) group. The levels of malondialdehyde (MDA) and the activities of SOD and CAT increased significantly in the DI group compared with the control group. The activity of SOD and the levels of MDA decreased significantly in the DI+Vit group compared with the DI group. The differences between the DI+Vit and control groups according to the MDA levels and the activities of both SOD and CAT were statistically significant. These results suggest that treating rats with a single dose of diazinon increases LPO and some antioxidant enzyme activities in the rat myocardium and, in addition, that single-dose treatment with a combination of vitamins E and C after the administration of diazinon can reduce LPO caused by diazinon, though this treatment was not sufficiently effective to reduce the values to those in control group.     

Hematological effects of textile mill effluent on freshwater fish Oreochromis mossambicus (Trewaves)

O. mossambicus was exposed to sublethal concentrations of a textile mill effluent to study the hematological changes as a function of feeding/starvation, aeration/non-aeration and concentration. Increase in concentration produced a dose dependent increase in RBCs (0.87 x 10(6) to 1.63 x 10(6)/mm3), WBCs (0.070 x 10(6) to 0.520 x 10(6)/mm3), hemoglobin (3.7 to 5.6%) and hematocrit (9.0 to 12.3%) and a decrease in MCV (111.8 to 88.2 microns 3), MCHC (41.05 to 31.35%) and MCH (44.2 to 33.9 pg).     

Protective effect of glutathione and selenium against alloxan induced lipid peroxidation and loss of antioxidant enzymes in erythrocytes

Alloxan is a diabetogenic drug and is known to induce diabetes through generation of free radicals. The toxic oxygen species can be detoxified by antioxidant enzyme system and thus reduce the deleterious effect of lipid peroxidation. Erythrocytes exposed to alloxan induced lipid peroxidationin vivo as well asin vitro. Although alloxan treatment produced a deleterious effect on antioxidant enzymes, pretreatment with glutathione and selenium led to a recovery of the activities of superoxide dismutase and glutathione peroxidase. However, catalase activity increased on alloxan treatment. Alloxan reduced blood glucose level significantly within 60 min but thereafter a slow and steady rise was observed.     

Effects of mine effluent on uptake of Co,Ni, Cu,As, Zn,Cd, Cr and Pb by aquatic macrophytes

Concentrations of Ni, Co, Cu, Pb, Zn, Cd, Cr and As were determined in aquatic sediments, water and macrophytes collected from a fluvial system, contaminated by mine effluents. Myriophyllum verticillatum collected in May below the trace element point source accumulated 169 µg/g of Ni, 860 µg/g of Co, 37 µg/g of Cu, 31 µg/g of Pb, 92 µg/g of Zn, 6.9 µg/g of Cr and 1,200 µg/g of As (concentrations in dry weight). The aquatic macrophytes Nymphaea odoratae and Pontederia cordata accumulated the investigated trace elements to a much lesser extent. The concentrations of trace elements in Myriophyllum verticillatum decreased from May to August. Correlations were found between the concentrations of total Ni, Co and Cu in the bottom sediment and in the submerged macrophytes. However, there was no correlation between the amounts of these trace elements extractable by 0.5 N HCl from the sediments and the concentrations in the macrophytes.     

Effects of Cadmium on Antioxidant Enzyme Activities in Sugar Cane

Sugar cane (Saccharum officinarum L. cv. Copersucar SP80-3280) seedlings were grown in nutrient solution with varying concentrations (0, 2 and 5 mM) of cadmium chloride for 96 h. Leaves were analysed for catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD) activities. Although a clear effect of CdCl₂ on plant growth was observed, the activity of SOD was not altered significantly. However, the CAT activity decreased as the concentration of CdCl₂ increased. GR exhibits a significant increase in activity at 2 and 5 mM CdCl₂. CAT and SOD isoenzymes were further characterised by analysis in non-denaturing PAGE. Activity staining for SOD revealed up to seven isoenzymes in untreated control and 2 mM CdCl₂ treated plants, corresponding to Cu/Zn-SOD isoenzymes. At 5 mM CdCl₂, only six Cu/Zn-SOD isoenzymes were observed. No Fe-SOD and Mn-SOD isoenzymes were detected. For CAT, one band of activity was observed.     

Cytokinin-induced activity of antioxidant enzymes in transgenic Pssu-ipt tobacco during plant ontogeny

Cytokinin (CK) content and activities of several antioxidant enzymes were examined during plant ontogeny with the aim to elucidate their role in delayed senescence of transgenic Pssu-ipt tobacco. Control Nicotiana tabacum L. (cv. Petit Havana SR1) and transgenic tobacco with the ipt gene under the control of the promoter of small subunit of Rubisco (Pssu-ipt) were both grown either as grafts on control rootstocks or as rooted plants. Both control plant types showed a decline in total content of CKs with proceeding plant senescence. Contrary to this both transgenic plant types exhibited at least ten times higher content of CKs than controls and a significant increase of CK contents throughout the ontogeny with maximal values in the later stages of plant development. Significantly higher portion of O-glucosides was found in both transgenic plant types compared to control ones. In transgenic plants, zeatin and zeatin riboside were predominant type of CKs. Generally, Pssu-ipt tobacco exhibited elevated activities of antioxidant enzymes compared to control tobacco particularly in the later stages of plant development. While in control tobacco activity of glutathione reductase (GR) and superoxide dismutase (SOD) showed increasing activity up to the onset of flowering and then gradually decreased, in both transgenic types GR increased and SOD activity showed only small change throughout the plant ontogeny. Ascorbate peroxidase (APOD) was stimulated in both transgenic types. The manifold enhancement of syringaldazine and guaiacol peroxidase activities was observed in transgenic grafts throughout plant ontogeny in contrast to control and transgenic rooted plants, where the increase was found only in the late stages. Electron microscopic examination showed higher number of crystallic cores in peroxisomes and abnormal interactions among organelles in transgenic tobacco in comparison with control plant. The overproduction of cytokinins resulted in the stimulation of activities of AOE throughout the plant ontogeny of transgenic Pssu-ipt tobacco.