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In this experiment, effect of lead (Pb) + chromium (Cr) mixture on superoxide dismutase (SOD) in the liver of Labeo rohita at a concentration of 11.1 mgL-1 was observed. The ammonium sulphate precipitation and ion exchange chromatography techniques were successfully used to purify SOD. After purification, SOD activity of control and Pb+Cr treated fish was noted as 581.00 and 645.45 UmL-1, respectively while the specific activity was 1383.33 and 1613.62 Umg-1, respectively. The fold purification value of SOD was 2.75 and 2.45 for control and stressed fish, respectively. The recovery was calculated as 77.06 and 57.43% for control and stressed fish, respectively. The results of kinetic characterization showed that SOD form control and exposed fish had maximum activity at pH 6.5 and 7.0. Temperature also had a significant effect on activity of SOD. The SOD activity was measured maximum at 30°C for both control and Pb+Cr exposed fish. The Km value of liver SOD for control and Pb+Cr treated L. rohita was calculated as 1.48 and 0.62 mM, respectively. The value of Vmax for SOD from liver of control and Pb+Cr exposed fish was 1000 and 570 U mL-1, respectively. The enthalpy of denaturation (ΔH*) for liver SOD from control and Pb+Cr exposed L. rohita was computed as 3.492 and 2.802 KJ mol-1 at 40°C, respectively and these values were dropped off with increasing the temperature until it remains 3.251 and 2.561 KJ mol-1 at 70°C, respectively. The free energy of thermal denaturation (ΔG°) of liver SOD was slightly increased with increasing temperature until 75°C which shows its resistance against heat. The values of ΔG° was observed as 58.03 and 57.95 KJ mol-1 for control and exposed fish at 40°C, respectively while the same was increased upto 62.37 and 62.00 KJ mol-1 at 70°C, respectively. It was concluded from negative value of ΔS* (entropy of inactivation) that the SOD is stable thermodynamically. [ABSTRACT FROM AUTHOR]

The current study was conducted to determine the tolerance limits of Indian major carps viz. Catla catla, Cirrhina mrigala and Labeo rohita against pesticides mixture (Bifenthrin + Chlorpyrifos + Endosulfan) and to see it effect on antioxidant enzyme like superoxide dismutase (SOD) activity in the liver of these species. The 96-hr LC50 and lethal concentration of pesticides mixture (BIF+CPF+END) for C. catla, C. mrigala and L. rohita was determined in the static bioassay methods as 1.09, 1.81 1.63 and 1.90, 2.78, 2.30 µgL-1, respectively.C. catla exhibited higher sensitivity toward tertiary pesticides mixture followed by L. rohita and C. mrigala. The activity of SOD in the liver of all three fish species exposed to pesticides mixture was significantly (p<0.05) higher as compare to control fish. The SOD activity showed time dependent increasing trend in the liver of all three fish species. [ABSTRACT FROM AUTHOR]

Concerns regarding zinc oxide nanoparticles (ZnO-NPs) have gained much attention due to their unique properties and widespread applications in cosmetics, electronics and medicinal industry that may induce an adverse impact not only on specific ecosystem but also on human health. ZnO-NPs were synthesized by coprecipitation method and characterization was done by Scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analysis. SEM showed the hexagonal wurtzite crystal structure of particles. From XRD pattern, average particle size, lattice parameters (a and c), X-ray density and volume of unit cell of zinc oxide nanoparticles were 52.22 nm, (a =3.25 Å and c=5.21 Å), 5.0 g/cm3 and 54.82 ų, respectively. FT-IR confirmed the attached compound of synthesized nanoparticles. The acute toxicity of ZnO-NPs was determined by using fish, Labeo rohita as a genetic model during this study. The mean 96-h LC50 and lethal concentration were measured as 31.15 and 57.84 mg/L, respectively. Oxidative stress in terms of catalase, lipid peroxidation and superoxide dismutase was also determined in fish gills, muscle, liver and heart after chronic exposure of ZnO-NPs for 80 days and sampling were done on 20, 40, 60 and 80 days. Significantly decreased catalase and superoxide dismutase activity was determined in selected fish organs. However, level of lipid peroxidation was significantly increased in the fish organs as compared to control group. The overall results indicated that induced toxicity mechanism of ZnO-NPs in aquatic ecosystem was oxidative stress. [ABSTRACT FROM AUTHOR]