|Physiological and cytological responses of the marine diatom Skeletonema costatum to 2,4-dichlorophenol|
Yang, S.; Wu, R.S.S.; Kong, R.Y.C. (2002). Physiological and cytological responses of the marine diatom Skeletonema costatum to 2,4-dichlorophenol. Aquat. Toxicol. 60(1-2): 33-41
In: Aquatic Toxicology. Elsevier Science: Tokyo; New York; London; Amsterdam. ISSN 0166-445X, more
Diatoms; Energy budget; Pigments; Skeletonema costatum (Greville) Cleve, 1873 [WoRMS]; ANW, USA, Maine [Marine Regions]; Marine
|Authors|| || Top |
- Yang, S.
- Wu, R.S.S.
- Kong, R.Y.C.
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-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-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-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-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.