Toxic pollutants are metabolic poisons that can seriously injure or destroy the photosynthetic organisms upon which the food chain depends. Since microalgae play a key role in marine ecosystems, marine microalgae are proposed as excellent bio-indicators of pollution due to their high sensitivity, which can give warning of the toxic effects of chemicals sooner than any other species. The aim of this work concentrated on the effect of different concentrations of the antifouling biocide (Irgarol 1051) on growth and chlorophylls content (as an essential metabolite) of the two marine unicellular green algae Chlorella salina and Dunaliella bardawil that usually used in fish feeding. The growth of the wall-less Dunaliella bardawil was more sensitive to Irgarol 1051 than the walled cells Chlorella salina, although the concentrations used were greatly different. The product of photosynthesis in the two algal species greatly affected since in the presence of Irgarol 1051, a serious destructive effect was observed. The cell wall appeared to play a significant role in protecting the organism against toxicity of the antifouling agent either by adsorption or degradation. The strength of toxicity depends mainly on the concentration of the antifouling agent, the length of culturing period and the type of organism tested.
To better understand the toxicity of an antifouling booster biocide Irgarol-1051 degradation product M2 3-4-tert-butylamino-6-methylthiol-s-triazin-2-ylamino pro-pionaldehyde this study utilized a DNA microarray technique to explore the genotoxicity of M2. The Affymetrix Inc. rat genome 230 2.0 GeneChip was employed to examine alterations in gene regulation in rat hepatoma cells exposed to 30 μmol/L of M2 for 96 h.The results showed that 38 genes were significantly p＆lt;0.002 5 altered by M2 at two-fold changes in all the four possible control/exposure comparisons. Accn5 was the only well described gene consistently being suppressed which likely altered the epithelial sodium channel ENaC .10 and 82 annotated genes were up-and down-regulated in at least one of the control/exposure comparisons respectively. The induced genes were mainly involved in the nucleus belonging to the cellular component. The largest categories of suppression concerned G-protein coupled receptor protein signaling pathways belonging to the biological process and integral to membranes belonging to the cellular component.
