A. Bhagyalakshmi

Subacute stress induced by sumithion on certain biochemical parameters in Oziotelphusa senex senex, the fresh-water rice field crab

Healthy crabs (Oziotelphusa senex senex) were exposed to 3 concentrations of sumithion, with a control group over a 30-day period. The glycogen content of the hepatopancreas was depleted on acute exposure but was elevated after acclimatization. The glycogen phosphorylase activity was elevated on acute exposure, whereas phosphorylase activity decreased after acclimatization. The increase in phosphorylase activity and the decrease in glycogen content indicated increased glycogenolysis at tissue level after acute exposure but on acclimatization the tissue glycogenolysis appeared to be suppressed. Sumithion was found to decrease the activity levels of SDH and MDH and to elevate LDH. The increase in LDH and the decrease in SDH and MDH in the hepatopancreas indicated the development of anaerobic conditions at tissue level in the stressed crabs. In general, acclimatization to a toxic solution seems to result in the elevation of the synthetic phase of carbohydrate metabolism.

Chronic sumithion toxicity: Effect on carbohydrate metabolism in crab muscle

Chronic sumithion toxicity in experimental crabs was induced by exposing them for 15 and 30 days to 0.04 ppm sumithion solution. The enzymes concerned with glycogenolytic metabolism (phosphorylase), glycolytic metabolism (aldolase), aerobic metabolism [succinate dehydrogenase (SDH), malate dehydrogenase (MDH)], anaerobic metabolism, lactate dehydrogenase (LDH) and alanine amino transaminase (AIAT)], were assayed in the muscle of control and experimental crabs. Glycogen, pyruvic acid, lactic acid were also estimated in the muscle of both control and experimental crabs. The muscle tissue of chronic sumithion-exposed crab exhibited suppressed glycogenolysis and glycolysis with an onset of gluconeogenesis. In general, chronic sumithion exposure seems to result in an elevation of the synthetic phase of muscle carbohydrate metabolism.

Changes in hemolymph glucose, hepatopancreas glycogen, total carbohydrates, phosphorylase and amino transferases of sumithion-stressed freshwater rice-field crab (Oziotelphusa senex senex)

Adult crabs were exposed to 3 concentrations of sumithion with a control group over a 20-day period. Hemolymph glucose levels were monitored in each group over the course of the experiment. The group demonstrating the most acute and sustained hyperglycemia (2 ppm sumithion) was then analyzed, as also the controls for changes in hepatopancreas glycogen, total carbohydrates, phosphorylase and aminotransferases. Significant (P less than 0.001) depressions in hepatopancreas glycogen and total carbohydrates and elevations of phosphorylase and transaminases were observed in sumithion-stressed crabs when compared with controls. These changes are discussed with respect to gluconeogenesis and possible influences of hyperglycemic hormone, which is released into hemolymph of stressed crab.

Muscle nitrogen metabolism of freshwater crab, Oziotelphusa senex senex fabricius, during acute and chronic sumithion intoxication

Muscle nitrogen metabolism was studied in the crab, Oziotelphusa senex senex Fabricius, following acute (1 day) and chronic (20 days) exposure to 0.1 ppm sumithion solution. Proteolysis in the muscle tissue in acute exposure was increased after exposure for 24 h. The muscle tissue of chronically exposed crabs seemed to develop a more efficient mechanism for the detoxication of ammonia compared with that of acutely exposed crabs. The survival of crabs after chronic sumithion intoxication has been attributed to adaptive changes involving protein synthesis and the metabolism of ammonia.

In vivo sub-acute physiological stress induced by sumithion on carbohydrate metabolism in hepatopancreas of Oziotelphusa senex senex Fabricius

Abstract The in vivo effect of sumithion (fenitrothion; dimethyl- O -(3-methyl-4-nitrophenyl)-phosphorothioate) on carbohydrate metabolism in the hepatopancreas of Oziotelphusa senex senex Fabricius has been studied at a sub-acute level (1/10 of 24 h LC 50 ; i.e. 0.04 ppm) after 15 and 30 days of exposure. The hepatopancreatic tissue of sumithion-exposed crabs exhibited reduced glycolysis with an increase in gluconeogenesis.

In vivo sub-acute physiological stress induced by Sumithion on some aspects of oxidative metabolism in the fresh water crab

Specimens of fresh water crab, Oziotelphusa senex senex were exposed to sub-lethal concentration (25 % of LC50/48 hr) of Sumithion for 7 days. Sumithion was found to inhibit the activity levels of acetylcholinesterase, succinate dehydrogenase,isocitrate dehydrogenase and pyruvate dehydrogenase, activate lactate dehydrogenase and cause accumulation of acetylcholine in the hepatopancreas and muscle. The increase in lactate dehydrogenase and the decrease in succinate, isocitrate and pyruvate dehydrogenases in these tissues indicate the development of anaerobic conditions and is interpreted as a functional adaptation to pesticide induced metabolic stress.

Hyperglycemic activity of crab and scorpion hormones in grasshopper (Poecilocerus pictus)

Hyperglycemic hormones obtained from crab and scorpion both cause significant, dose-dependent elevations of hemolymph sugars in the grasshopperPoecilocerus pictus. These results suggest a highly conservative evolution of some mandibulate arthropod neuro-hormones.

Effect of sumithion on ovarian growth of a fresh water rice field crab (Oziotelphusa senex senex fabricius)

Sumithion exposure resulted in a decrease in the ovarian growth of the intact female crab, Oziotelphusa senex senex Fabricius apparently by the release of the gonad-inhibiting hormone (GIH).

Effect of sublethal concentrations of sumithion on limb regeneration of fresh water field crab Oziotelphusa senex senex.

The initiation and progress of regeneration following the removal of the left 4th walking leg were altered in the crab (Oziotelphusa senex senex) by exposure to sumithion. Depending on the concentration used, sumithion caused a complete inhibition of regeneration, a delay of initiation of limb bud development or a reduction of limb bud growth rate. Crustacean limb regenration can also be used as a sensitive bioassay for studying the effects of environmental pollutants.

Sumithion-induced hyperglycemia in the freshwater rice field crab Oziotelphusa senex senex Fabricius.

Sumithion produced a significant (P < 0.001) increase in the hemolymph sugar level of the intact crab, Oziotelphusa senex senex Fabricius apparently by triggering release of the hyperglycemic hormone (HGH).