TY - JOUR AU - HAZLINA, A.Z. AU - DEVANTHIRAN, L AU - FATIMAH, H PY - 2019/03/20 Y2 - 2024/03/29 TI - MORPHOLOGICAL CHANGES AND DNA DAMAGE IN Chlorella vulgaris (UMT-M1) INDUCED BY Hg2+ JF - Malaysian Applied Biology JA - MAB VL - 48 IS - 1 SE - Research Articles DO - UR - https://jms.mabjournal.com/index.php/mab/article/view/2286 SP - 27-33 AB - <p><span class="fontstyle0">This study reported the effects of Hg</span><sup><span class="fontstyle0">2+ </span></sup><span class="fontstyle0">on the morphology and DNA of a microalga, </span><em><span class="fontstyle2">Chlorella vulgaris </span></em><span class="fontstyle0">(UMT-M1).<br />Morphological changes and DNA damage in cells were analysed using scanning electron microscope (SEM) and Comet assay, respectively. The half maximal inhibitory concentration (i.e. IC</span><span class="fontstyle0">50 </span><span class="fontstyle0">) of Hg</span><span class="fontstyle0"><sup>2+</sup> </span><span class="fontstyle0">on the growth of </span><span class="fontstyle2"><em>C</em>. <em>vulgaris</em> </span><span class="fontstyle0">obtained from the dose-response curve was 0.72 mg/L. Under SEM, it was observed that Hg</span><sup><span class="fontstyle0">2+ </span></sup><span class="fontstyle0">treated cells become smaller in size (i.e. 2.1±0.1 µm) compared to normal cells (i.e. 3.2±0.1 µm). The morphology of cells changed from an intact microalgal cells with smooth spherical surface to a slightly roughened surface and shrivelled shape. Apoptotic bodies were also observed under 0.001, 0.01 and 0.1 mg/L of Hg</span><span class="fontstyle0">2+ </span><span class="fontstyle0">but not in 1.0 mg/L Hg</span><sup><span class="fontstyle0">2+</span></sup><span class="fontstyle0">. These results indicate that Hg</span><sup><span class="fontstyle0">2+ </span></sup><span class="fontstyle0">may induce apoptotic cell death at low concentrations but not at the highest concentration of 1.0 mg/L. The highest percentage of cells with comet level of 4 was observed in 1.0 mg/L Hg</span><sup><span class="fontstyle0">2+</span></sup><span class="fontstyle0">. However, Hg</span><sup><span class="fontstyle0">2+ </span></sup><span class="fontstyle0">is genotoxic to the microalga even at low concentration. In conclusion, Hg</span><sup><span class="fontstyle0">2+ </span></sup><span class="fontstyle0">can exert its toxic effects on </span><span class="fontstyle2"><em>C</em>. <em>vulgaris </em></span><span class="fontstyle0">by changing the microalgal morphology, damaging the microalgal DNA and inducing cell death in the microalgal cells using different pathways at different concentrations.</span></p> ER -