Search results for "Toxicant"
showing 10 items of 24 documents
Autophagy as a defense strategy against stress: focus on Paracentrotus lividus sea urchin embryos exposed to cadmium
2015
Autophagy is used by organisms as a defense strategy to face environmental stress. This mechanism has been described as one of the most important intracellular pathways responsible for the degradation and recycling of proteins and organelles. It can act as a cell survival mechanism if the cellular damage is not too extensive or as a cell death mechanism if the damage/stress is irreversible; in the latter case, it can operate as an independent pathway or together with the apoptotic one. In this review, we discuss the autophagic process activated in several aquatic organisms exposed to different types of environmental stressors, focusing on the sea urchin embryo, a suitable system recently in…
Environmental epigenetics in zebrafish
2017
Abstract It is widely accepted that the epigenome can act as the link between environmental cues, both external and internal, to the organism and phenotype by converting the environmental stimuli to phenotypic responses through changes in gene transcription outcomes. Environmental stress endured by individual organisms can also enforce epigenetic variations in offspring that had never experienced it directly, which is termed transgenerational inheritance. To date, research in the environmental epigenetics discipline has used a wide range of both model and non-model organisms to elucidate the various epigenetic mechanisms underlying the adaptive response to environmental stimuli. In this rev…
Determination of haemoglobin adducts of acrylamide and glycidamide in smoking and non-smoking persons of the general population
2005
Acrylamide (AA) is a food-borne toxicant suspected to be carcinogenic to humans. It is formed in the heating process of starch-containing food. Currently, there is a great discussion about the possible human health risks connected with the dietary uptake of acrylamide. Haemoglobin adducts of acrylamide and its oxidative metabolite glycidamide are both markers of biochemical effect. However, because glycidamide has a higher carcinogenic potency than acrylamide itself, the glycidamide adduct might mirror the genotoxicity better than acrylamide adducts. In order to gain more information about the human metabolism of acrylamide, we investigated a small group of persons for the effective interna…
Aryl hydrocarbon receptor activation by cAMP vs. dioxin: divergent signaling pathways.
2005
Even before the first vertebrates appeared on our planet, the aryl hydrocarbon receptor ( AHR ) gene was present to carry out one or more critical life functions. The vertebrate AHR then evolved to take on functions of detecting and responding to certain classes of environmental toxicants. These environmental pollutants include polycyclic aromatic hydrocarbons (e.g., benzo[ a ]pyrene), polyhalogenated hydrocarbons, dibenzofurans, and the most potent small-molecular-weight toxicant known, 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD or dioxin). After binding of these ligands, the activated AHR translocates rapidly from the cytosol to the nucleus, where it forms a heterodimer with aryl hydroc…
Effect of the lipid regulator Gemfibrozil in the Cladocera Daphnia magna at different temperatures.
2016
ABSTRACTIn the present study, an ecotoxicological approach to the evaluation of Gemfibrozil (GEM) as an emerging organic pollutant was done. In order to assess its toxicity, tests were conducted using the cladocera Daphnia magna. Experiments were carried out at 22°C and 28°C. EC50, feeding behavior, and chronic toxicity tests (21 days) were evaluated in D. magna exposed to GEM as well as cholesterol levels at 21-day chronic exposure. D. magna GEM EC50 values (24 h) in our experimental conditions were 148.75 and 116.24 mg L−1 at 22°C and 28°C, respectively. Test concentrations of 0.1, 0.5, 1.0, 5.0 and 7.5 mg L−1 were selected for subacute and chronic experiments. Subacute short-term test (f…
Acute, chronic and sublethal effects of the herbicide propanil on Daphnia magna.
2003
Acute and chronic toxicity tests with propanil were conducted on Daphnia magna. The 24 and 48 h LC50 were 43.74 and 5.01 mg/l respectively. Chronic toxicity tests were carried out using sublethal propanil concentrations (0.07, 0.10, 0.21 and 0.55 mg/l) during 21 days. The effect of propanil on survival, reproduction and growth of D. magna organisms was monitored. The parameters used to evaluate herbicide effect on reproduction were: mean total young ones 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 determined after 21 days of exposure to the herbicide. Reproducti…
Thiobencarb-Induced Changes in Acetylcholinesterase Activity of the Fish Anguilla anguilla
2002
Abstract European eels (Anguilla anguilla) were exposed to sublethal thiobencarb concentrations in a continuous flow-through system for 4 days. Brain, muscle, and gill acetylcholinesterase (AChE) activities were evaluated after 2, 12, 24, 48, 72, and 96 h herbicide exposure. Thiobencarb induced significant inhibitory effects on the total and specific AChE activity of A. anguilla, ranging from >30–40% inhibition in eel brain and gills to >50% inhibition in muscle tissue 2 h after the initial exposure. In a second experiment, eels were exposed to thiobencarb for 96 h and then allowed a period of recovery in pesticide-free water. Following 1 week of recovery, the AChE activity of affected eels…
Eel ATPase activity as biomarker of thiobencarb exposure
2003
Abstract European eels ( Anguilla anguilla ) were exposed to a sublethal thiobencarb concentration of 0.22 mg/L in a flow-through system for 96 h. Mg 2+ and Na + –K + adenosine triphosphatase (ATPase) activities were evaluated in gill and muscle tissues at 2, 12, 24, 48, 72, and 96 h of thiobencarb exposure. Gill ATPase activities were rapidly inhibited from 2 h of contact onward. Highest inhibition was registered for Na + , K + -ATPase (85%) from 2 to 12 h. Both Mg 2+ and total ATPase were inhibited (>73%) during the first hours of toxicant exposure. At the end of the exposure period (96 h) ATPase activities were still different from those of the controls (>50%). Significant inhibition was…
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…