Past Issue

In the present investigation, cadmium, copper, lead and zinc induced biochemical changes were studied in post larval stages of Penaeus monodon under long term chronic test (30 days). The total protein content, level of lipid peroxidation, reduced glutathione and the activity of catalase, glutathione S-transferase and acetylcholinesterase in the tissues of Penaeus monodon decreased with the increase in concentrations of heavy metal concentrations used in the long term chronic test for 30 days.

Metals are biologically important. If the threshold concentration of the metal increases in the environment, they may interfere with the metabolic activity of organisms. In the presenting study, an attempt was made to investigate the effect on nickel on oxidative stress and antioxidant enzymes in the liver tissue of Cirrhinus mrigala.

The acute toxicity and bioaccumulation of cadmium, copper, lead and zinc to Penaeus monodon (Tiger prawn) was evaluated in static tests. Each test lasted up to 4 d and LC50 values were also calculated. The toxicity of each metal increased with exposure time for cadmium, copper, lead and zinc. The 96 hours LC50 values for cadmium, copper, lead and zinc were 1.72, 0.66, 0.41, 2.36 mg/l. Lead was toxic metal to P.monodon than zinc followed by cadmium and copper tested. The order of toxicity was Pb>Cu>Cd>Zn.

Chloramphenicol is a powerful antibiotic and is mostly used for curing both gram –negative and gram positive diseases. Ceric ammonium sulphate (CAS), a versatile oxidizing agent has been employed in acetic acid – water 40% (v/v) medium to oxidize the alcoholic groups present in chloramphenicol. This investigation has been carried out to evaluate the kinetic parameters such as rate with respect to each reactant and rate constant and thermodynamic parameters like Energy of activation(Ea), Enthalpy of activation(∆H#) and Entropy of activation(∆S#).

Ceric ammonium sulphate (CAS) is well known to oxidize carbon compounds in various acid media via the formation of 1:1 cerium (IV) – substrate complex which undergoes dissociation unimolecularly in the rate determining step. In the present work, the structure reactivity correlation in oxidation reaction of chloramphenicol, a powerful antibiotic has been ascertained using ceric ammonium sulphate as a versatile oxidizing agent in acetic acid – water 50% (v/v) media.