Physiological and cytological responses of the marine diatom, Skeletonema costatum, to 2,4-dichlorophenol (2,4-DCP) were investigated after exposing algal cultures to 1-6 mg l⁻¹ of 2,4-DCP for 96 h. Growth rate of the diatom was significantly reduced by 2,4-DCP at and above 3.0 mg l⁻¹ while other biological parameters such as photosynthetic and respiration rates, carotenoid and protein content, ATP level and adenylate energy charge were unaffected. Exposure to 6.0 mg l⁻¹ 2,4-DCP for 96 h resulted in the total lipid content being increased to 304%, while the RNA/DNA ratio was reduced to 31% of the control values. A parallel study by transmission electron microscopy further confirmed the increase in cellular lipid content, as evidenced by the accumulation of lipid droplets within diatom cells. A slight increase in carbohydrate (+37.8%) and decrease in chlorophyll a (-20.4%) and total chlorophyll c (-14.4%) were also found at 6.0 mg l⁻¹ 2,4-DCP. Although 2,4-DCP is known to uncouple oxidative phosphorylation, our results show that energy production was not significantly inhibited at sublethal concentrations of 2,4-DCP. The observed growth inhibition in S. costatum caused by 2,4-DCP was associated with an increase in energy storage and inhibition of protein synthesis, as indicated by a reduction in RNA/DNA ratio. Copyright © 2002 Elsevier Science B.V. All rights reserved.
CitationYang, S., Wu, R. S. S., & Kong, R. Y. C. (2002) Physiological and cytological responses of the marine diatom Skeletonema costatum to 2,4-dichlorophenol. Aquatic Toxicology, 60(1-2), 33-41. doi: 10.1016/S0166-445X(01)00258-2
- Energy charge
- Energy reserve