Insecticides induced biochemical changes in freshwater microalga Chlamydomonas mexicana

Abstract

The effect of insecticides (acephate and imidacloprid) on a freshwater microalga Chlamydomonas mexicana was investigated with respect to photosynthetic pigments, carbohydrate and protein contents, fatty acids composition and induction of stress indicators including proline, superoxide dismutase (SOD) and catalase (CAT). C. mexicana was cultivated with 1, 5, 10, 15, 20 and 25 mg L(-1) of acephate and imidacloprid. The microalga growth increased with increasing concentrations of both insecticides up to 15 mg L(-1), beyond which the growth declined compared to control condition (without insecticides). C. mexicana cultivated with 15 mg L(-1) of both insecticides for 12 days was used for further analysis. The accumulation of photosynthetic pigments (chlorophyll and carotenoids), carbohydrates and protein was decreased in the presence of both insecticides. Acephate and imidacloprid induced the activities of superoxide dismutase (SOD) and catalase (CAT) and increased the concentration of proline in the microalga, which play a defensive role against various environmental stresses. Fatty acid analysis revealed that the fraction of polyunsaturated fatty acids decreased on exposure to both insecticides. C. mexicana also promoted 25 and 21% removal of acephate and imidacloprid, respectively. The biochemical changes in C. mexicana on exposure to acephate and imidacloprid indicate that the microalga undergoes an adaptive change in response to the insecticide-induced oxidative stress.

Imidacloprid modifies the mitotic kinetics and causes both aneugenic and clastogenic effects in the macrophyte Bidens laevis L.

“…Toxicity of IMI on aquatic photosynthetic organisms has been scarcely studied. Specifically, the available information is limited to growth inhibition of the macrophyte Lemna gibba (EC 50 = 740 mg/L; Daam et al., 2013) and unicellular algae (LC 50 = 20 mg/L for Chlamydomonas mexicana and NOEC = 10 mg/L IMI for Scenedesmus subspicatus ; Kumar et al., 2015; IUPAC PPDB, 2018). Particularly, genotoxicity in photosynthetic organisms has been reported in terrestrial model species.…”

Microalgae-Enabled Wastewater Treatment: A Sustainable Strategy for Bioremediation of Pesticides

“…The side effects of bioaccumulations to the microalgal cells are countered by the production of antioxidative enzymes that can eliminate excessive ROS by scavenging these free radicals [115]. It was reported that insecticides acephate and imidacloprid with concentration of 15 mg/L induced an adaptive biochemical change in freshwater microalgae Chlamydomonas mexicana, where superoxide dismutase activity (SOD) antioxidant enzyme was significantly increased as part of the defense mechanisms [116]. The photosynthetic algae native to polar regions, Cocomyxa subellipsoidea hydrolyze and breakdown paraoxon, malathion and diazinon organophosphates through the formation of ROS have been demonstrated [117].…”

The Use of Algae and Fungi for Removal of Pharmaceuticals by Bioremediation and Biosorption Processes: A Review

“…• -superoxide radicals, OH • -hydroxyl radical, HO 2 • -perhydroxy radical, and RO • -alkoxy radicals) and nonradical forms (e.g., H 2 O 2 -hydrogen peroxide and 1 O 2 -singlet oxygen). At normal levels, these species act as essential signaling molecules to control cellular metabolism; however, at excess levels, these species can cause severe damage to cellular components and an increased rate of mutagenesis that ultimately leads to programmed cell death [167]. Such as for fungi, pollutant degradation by algae seems to involve intracellular and extracellular enzymatic systems (Figure 3).…”