Search

Cadmium (Cd) is a toxic-heavy metal that induces a wide range of behavioural, biochemical and physiological effects in aquatic organisms. Oxidative damage has been proposed as a possible mechanism involved in cadmium toxicity. The current study was carried out to evaluate the antioxidant activity of Spirulina as feed additive (1 mg/L) against the toxicity of cadmium (Cd) 0.5 mg/L in freshwater mussel Unio ravoisieri. At the end of the exposed period of 4 days, digestive gland antioxidant status Superoxide dismutase, Catalase, Glutathione-S-transferase and damage markers such as Malondialdehyde and Protein carbonyl were determined. Associations between biomarkers were assessed by a multivariate analysis technique, principal component analysis (PCA). The results of this study revealed that digestive gland antioxidant status showed a significant decrease when mussels were exposed to Cd. Superoxide dismutase, Catalase and Glutathione-S-transferase activities in the Cd + SP group were significantly higher than the Cd group (p < 0.05). Tissue levels of malondialdehyde and protein carbonyl in the Cd + SP group were significantly lower than the Cd group (P < 0.05). Our results show that the pretreatment with Spirulina protects the mussel from Cadmium-induced tissue damage by its antioxidant properties. [ABSTRACT FROM AUTHOR] more...

Biomonitoring has become a useful tool in environmental risk assessment of anthropogenic activities releasing disturbing pollutants. Permethrin, used worldwide to control a wide range of pest insects, can threaten aquatic biota, potentially useful as precocious bioindicators in ecotoxicology. This study seeks to assess the acute toxicity permethrin to the freshwater beetle, its availability in water, as well as, its uptake. The acute toxicity of permethrin to non-target species was studied under laboratory conditions to assess its effect, after the exposure 48 h, on the freshwater beetle Laccophilus minitus considering changes in some enzymatic activities; a specific biomarker of neurotoxicity (acetylcholinesterase) and a non-specific biomarker of oxidative stress (superoxide dismutase and catalase). The rates of permethrin in water and insects were determined using gas chromatography. The low measured concentration of the pesticide 0.0013 μg/L didńt modify the SOD and CAT activities in comparison with controls, only the high concentrations (0.023 and 0.18 μg/L) induced a significant increase in the enzyme activity. A similar profile was recorded for the H2O2 level. The permethrin treatment induced a drastic depletion of AChE activity. As outcomes, uptake at a low level (<6.8 ± 0.43 ng/g dry weight) showed to be the factor underlying the alterations in the beetles exposed to permethrin. Such findings provide information on the behaviour of permethrin within the environment and its biological target through its neurotoxicity and induction of oxidative stress in a freshwater beetle. [ABSTRACT FROM AUTHOR] more...

To understand acute toxicity and oxidative stress of perfluorinated compounds in the freshwater ecosystems, we exposed freshwater mussels (Unio ravoisieri) to perfluorooctane sulfonate (PFOS), over a range of concentrations from 10 to 100 mg/L, in a laboratory experiment. Lethal concentration (LC50) was of about 65.9 mg/L after 96 h of exposure. The oxidative stress was assessed in gill and digestive gland of the freshwater mussels after 7 days of exposure to different nominal PFOS concentrations (C1= 2 mg/L, C2 = 6 mg/L and C3= 10 mg/L). C1 and C2 increased significantly (p < .05) the superoxide dismutase activity in both tissues compared, while the highest C3 decreased the enzyme activity. This implements an unfavourable response that highlights the excess of reactive oxygen species produced after contamination. The Catalase activity was also increased by about 40.05% and 66.63%, respectively, in gill and digestive gland after exposure to C3. The Malondialdehyde (MDA) level was increased in both gill and digestive gland in a concentration-dependent pattern. In contrast, the contamination of U. ravoisieri by PFOS did not affect the acetylcholinesterase activity in both organs (p > .005). These results provided information on potential biomarkers that could be effectively applied for the monitoring of freshwater ecosystem using indicator species such as U. ravoisieri. [ABSTRACT FROM AUTHOR] more...