A new alternative local source of acetylcholinesterase (AChE) has been found to be sensitive towards several insecticides. AChE was purified from the brain tissue of Puntius javanicususing affinity chromatography (procainamide hydrochloride coupled with sephacryl 6B) with the total recovery of 40% at 8.48 purification fold. All carbamate (CB) insecticides tested at the concentration of 1 mg/L were capable of lowering AChE activity to less than 30%; Bendiocarp (18.80%), carbaryl (5.96%,), carbofuran (6.12%), methomyl (13.91%) and propoxur (15.851%). The P. javanicus AChE was found to be unaffected by several activated organophosphates (OP) such as acephate and dimethoate, while trichlorfon slightly inhibited the enzyme activity (p<0.05). Chlorpyrifos, diazinon, malathion and parathion lowered AChE activity to 43.02, 40.97, 37.11 and 46.72%, respectively. Pesticides that inhibit AChE activities more than 50% were further tested in different concentrations to determine the half maximal inhibitory concentration (IC50). Carbofuran and carbaryl showed the lowest IC50 value at 0.035 and 0.031 mg/L, respectively, as both showed no significant differences (p<0.05), followed by bendiocarp, propoxur, methomyl, malathion, diazinon, parathion and chlorpyrifos at 0.045, 0.076, 0.090, 0.063, 0.103, 0.151 and 0.202 mg/L, respectively. Based on these results, the sensitivity of AChE from brain P. javanicus brain tissue shows promise as an alternative biosensor for the detection of insecticides contamination.

The environmental toxicants such as copper are known to affect vital organ especially liver. This study examined the effects of copper sulfate (CuSO 4 ) on the liver morphological structure of P. javanicus. The untreated control, 0.1 and 0.3 mg/L CuSO 4 treated groups displayed normal polygonal structure of the hepatocyte. However, at the concentrations of 0.5, 1.0 and 5.0 mg/L CuSO 4 , the hepatostructure was significantly affected, as shown by the increasing number of dilation and congestion of sinusoids, vacuolation, macrophage activities and peliosis. The damage level and HSI value were increased while the number of hepatic nuclei per mm 2 was decreased with the increasing of copper concentration. In conclusion, this study shows that the degree of liver damage in P.javanicus is dependent to the dose exposure. � All Rights Reserved.

Due to the latest industrial development, many dangerous chemicals have been released directly or indirectly which resulted in the polluted water bodies. Water rehabilitation is an alternative way to restore the quality of water, followed by the environmental management to control the waste discharge to ensure the balance of the degradation rates or detoxifying by environmental factors. However, this process consumed a lot of time and cost. Besides, most of the metal ions, especially copper which is capable to bioaccumulate in aquatic organism and at the elevated level may cause physiological and biochemical alteration which leads to mortality. Environmental monitoring is the initial step presupposed evaluating the potential toxicity of effluent gushing at its purpose to discharge, avoiding the determining effects of contaminant in water bodies. Due to the high sensitivity of the aquatic life towards dissolving toxicant, the fish has been utilized as the biological measurement (Biomarker) to indicate the existence of toxicant exposure and/or the impact towards the evaluation of molecular, cellular to physiological level. Thus, this paper gives an overview of the manipulation of fish as a biomarker of heavy metals through behavior response, hepatocyte alteration, enzymatic reaction and proteomic studies which have proven to be very useful in the environmental pollution monitoring. � All Rights Reserved.

Molybdenum is an emerging pollutant worldwide. The objective of this study is to isolate molybdenum-reducing bacterium with the ability to grow on phenolic compounds (phenol and catechol). The screening process was carried out on a microplate. The bacterium reduced molybdenum in the form of sodium molybdate to molybdenum blue (Mo-blue). The bacterium required a narrow pH range for optimal reduction of molybdenum, i.e. Between pH 6.3 and 6.8, with temperature between 34 and 37 o C. Molybdate reduction to Mo-blue was best supported by glucose as the carbon source. However, both phenol and catechol could not support molybdate reduction. Other requirements for molybdate reduction included sodium molybdate concentrations between 15 and 30 mM, and phosphate concentration of 5.0 mM. The bacterium exhibited a Mo-blue absorption spectrum with a shoulder at 700 nm and a maximum peak near the infrared region at 865 nm. The Mo-reducing bacterium was partially identified as Enterobacter sp. Strain Saw-2. The capability of this bacterium to grow on toxic phenolic compounds and to detoxify molybdenum made it a significant agent for bioremediation.