Search results for "TOXICITY"
showing 10 items of 2261 documents
Expression of xenobiotic-metabolizing enzymes in propagatable cell cultures and induction of micronuclei by 13 compounds
1990
Activities of various xenobiotic-metabolizing enzymes were determined in 18 cell lines. Activities of cytochrome P450 reductase, microsomal epoxide hydrolase and glutathione transferase were detectable in all lines. The highest values were similar to the activities found in freshly isolated rat hepatocytes. Catalase activity was also present in all 12 investigated cell lines. Activity of UDP-glucuronosyl transferase was high in some lines, but low or undetectable in others. Activity of cytosolic epoxide hydrolase was not measurable in most lines, and was low in the others. Metabolism of benzo[a]pyrene was observed in eight out of nine examined lines, no activity being found in V79 cells. V7…
Acute toxicity of toluene, hexane, xylene, and benzene to the rotifers Brachionus calyciflorus and Brachionus plicatilis.
1992
A large number of studies on the biological effects of oil pollution in the aquatic environment deal with the effects of whole crude or refined oils or their water-soluble fractions. However, low boiling, aromatic hydrocarbons, which are probably the most toxic constituents of oil, have until now not been examined in sufficient detail. Toluene, benzene and xylene, constitute a major component of various oils. They may be readily lost by weathering but are toxic in waters that are relatively stagnant and are chronically polluted. Korn et al. have stated that toluene is more toxic than many other hydrocarbons such as benzene, though the latter are more water-soluble. Report of the effects of …
Acute lethal toxicity of some pesticides toBrachionus calyciflorus andBrachionus plicatilis
1991
Due to their widespread distribution and toxic nattwe pesticides may have a serious impact on the aquatic environment and exert adverse effects on the associated organisms. Acute bioassay tests have been used to determine the actual impact of various pesticides on aquatic life. Static acute toxicity tests provide rapid and reproductible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a data base for determining relative toxicity to a variety of species.
Metallothionein in the freshwater gastropod Melanopsis dufouri chronically exposed to cadmium: A methodological approach
2010
Previous studies have demonstrated that the use of differential pulse polarography (DPP) for metallothionein (MT) determination in marine gastropod tissues, particularly the digestive gland, requires taking into account the presence of heat-stable high molecular weight compounds that exhibit polarographic signal. In the present paper, similar compounds were identified in tissues from the freshwater snail Melanopsis dufouri which also interfere with MT determination by DPP and, due to their silver binding capacity, also interfere in the silver assay for MT quantification. Ultrafiltration seems to be effective in removing these high molecular weight compounds from heat-denatured homogenate su…
Effects of Terbuthylazine on Soil Fauna and Decomposition Processes
1996
Abstract Acute lethal and sublethal effects of terbuthylazine and the commercial herbicide preparation Gardoprim [terbuthylazine is the active ingredient (a.i.)] on soil organisms (microbes, oppioid mites, two gamasid mite species, enchytraeids, and nematodes) were studied. In the humus soil terbuthylazine had no toxic effects on soil animals tested. However, the herbicide preparation had acute toxic effects on enchytraeids [no-observed-effect level (NOEL) 1.0 g a.i./m 2 ] and both gamasid mites (NOEL 2.4 and 5.0 g a.i./m 2 ). According to filter paper test, the LC 50 value for oppioid mites was 14.5 g a.i./m 2 . In the humus soil the commercial preparation caused no dose-related mortality …
Effects of the herbicides Benzoylpropethyl and flampropisopropyl on rat liver mitochondria : an alteration in membrane fluidity ?
1984
Abstract The action of the herbicides benzoylpropethyl and flampropisopropyl, and the corresponding unesterified acids was studied in rat liver mitochondria. The herbicides were found to (a) inhibit the mitochondrial electron transfer in complex III or at the level of ubiquinone (I50 of 4 nmol mg protein−1 for flampropisopropyl and 18 for benzoylpropethyl with succinate as a substrate); (b) have an additional (however less sensitive) site of inhibition near succinate dehydrogenase; and (c) interfere with energy transfer. Sensitivity was increased 2- (benzoylpropethyl) and 3.5-fold (flampropisopropyl) as the rats age increased from 12–13 weeks to 23–26 weeks. The free acids were far less eff…
Acute toxicity of some chlorinated phenolic compounds toSelenastrum capricornutum and phytoplankton
1985
Acute toxicity of several chlorinated phenolic compounds detected in waste waters of bleached pulp was determined forSelenastrum capricornutum and indigenous phytoplankton using bioassays. Five of the phenolic compounds were chlorocatechols, four were chloroguaiacols and one was chlorosyringol. The response ofSelenastrum capricornutum to chemicals was measured by cell counting and phytoplankton14C-uptake. Chlorinated catechols inhibited the growth ofSelenastrum cultures in lower concentrations than chlorinated guaiacols. The increasing number of chlorine substituents on the phenolic ring increased the toxicity of both chlorinated catechols and guaiacols. The EC50-values (0-96 hr) of the com…
Assessment of chronic effects of tebuconazole on survival, reproduction and growth of Daphnia magna after different exposure times
2015
The effect of the fungicide tebuconazole (0.41, 0.52, 0.71 and 1.14mg/L) on survival, reproduction and growth of Daphnia magna organisms was monitored using 14 and 21 days exposure tests. A third experiment was performed by exposing D. magna to the fungicide for 14 days followed by 7 days of recovery (14+7). In order to test fungicide effects on D. magna, parameters as survival, mean whole body length, mean total number of neonates per female, mean number of broods per female, mean brood size per female, time to first brood/reproduction and intrinsic rate of natural increase (r) were used. Reproduction was seriously affected by tebuconazole. All tebuconazole concentrations tested affected t…
Effects of tetradifon on Daphnia magna during chronic exposure and alterations in the toxicity to generations pre-exposed to the pesticide.
2000
Daphnia magna was exposed to some nominal sublethal tetradifon concentrations (0.10, 0.18, 0.22 and 0.44 mg/l) during 21 days. Chronic toxicity tests were carried out using neonates of F(1) first brood (F(1)-1st) and F(1) third brood (F(1)-3rd) offspring generations from parentals (F(0)) pre-exposed to the pesticide. The effect of tetradifon on survival, reproduction and growth was monitored for the selected daphnid generations. The parameters used to evaluate pesticide effect on reproduction were: mean total young per female, mean brood size, time to first reproduction, mean number broods per female and intrinsic rate of natural increase (r). Survival and growth (body length) were also det…