Search results for "Lethal dose"
showing 4 items of 74 documents
The effect of two sulphur-containing pesticides, fenitrothion and endosulfan, on glutathione (GSH) content and on GSH S-transferase and gamma-glutamy…
1988
The glutathione (GSH) system of Procambarus clarkii (P.c.), the American red crayfish, is used as a marker of the effects of Fenitrothion (FT) and Endosulfan (ES), organophosphorus and organochlorinated insecticides, respectively. This system has been shown to be sensitive to different heavy metals poisoning, thus it has a double interest as marker for environmental contamination and as a potential source of xenobiotics or their metabolites to humans, since it is being fished commercially. The GSH content of the organ decreased 24 h after treatment with FT. FT promotes a 2-fold induction of GSH S-transferase (GST) activity at 6 h which is followed by a decrease of it at 24 h. The latter coi…
Effects of diazinon exposure on cholinesterase activity in different tissues of European eel (Anguilla anguilla).
1996
Cholinesterase (ChE) activity was measured in brain, plasma, and whole eye of Anguilla anguilla experimentally exposed to a sublethal concentration of 0.042 mg/liter (0.50 of the 96-hr LC50) of the organophosphorous pesticide diazinon. Whole eye was the tissue which revealed higher values of ChE activity (8.17 micromol/min/g) in nonexposed animals. Brain, plasma, and whole eye ChE activity of A. anguilla was inhibited at 6, 24, 48, 72, and 96 hr of diazinon exposure. Pesticide induced significant inhibitory effects on the ChE activity of this species ranging from >70% inhibition in brain tissue to >90% in plasma samples. Brain and plasma presented technical difficulties in their collection.…
The toxic and lethal effects of the trehalase inhibitor trehazolin in locusts are caused by hypoglycaemia
2003
SUMMARY The main blood sugar of locusts is trehalose, which is hydrolysed to two glucose units by trehalase. Homogenates of locust flight muscles are rich in trehalase activity, which is bound to membranes. A minor fraction of trehalase is in an overt form while the remainder is latent, i.e. active only after impairing membrane integrity. Trehazolin, an antibiotic pseudosaccharide,inhibits locust flight muscle trehalase with apparent Ki-and EC50 values of 10–8 mol l–1and 10–7 mol l–1, respectively. Trehazolin is insecticidal: 50 μg injected into locusts completely and selectively blocked the overt form of muscle trehalase (with little effect on latent activity) and killed 50% of the insects…
Photoinduced lethal and sublethal toxicity of retene, a polycyclic aromatic hydrocarbon derived from resin acid, to coregonid larvae
2004
A comparative investigation on the acute phototoxicity of retene to vendace (Coregonus albula) and whitefish (C. lavaretus), both having pelagial larvae in spring, was conducted. To test the concept of early warning of sublethal biomarkers in relation to lethality to posthatch stages, we examined the effects of ultraviolet-B (UV-B) and retene on the levels of cytochrome P4501A (CYP1A) and heat shock protein 70 (HSP70) by exposing the animals to elevated levels of these factors for 48 and 72 h, respectively. Whereas UV-B and retene on their own were not lethal, simultaneous retene and UV-B exposure caused very high mortality to both species. The median lethal concentration (LC50; i.e., the c…