The influence of temperature and salinity on the structure and function of mitochondria in chloride cells in the skin of the larvae of the turbot (Scophthalmus maximus)

Citation

Tytler P & Ireland J (1995) The influence of temperature and salinity on the structure and function of mitochondria in chloride cells in the skin of the larvae of the turbot (Scophthalmus maximus). Journal of Thermal Biology, 20 (1-2), pp. 1-14. https://doi.org/10.1016/0306-4565%2894%2900021-A

Abstract
Six separate groups of the larvae of the turbot (Scophthalmus maximus) from the same brood stock were incubated in three salinities (24, 34 and 44 ppt) and at three temperatures (12, 15 and 17°C). Relative levels in mitochondrial protein and mitochondrial membrane potentials in the cutaneous chloride cells of these larvae were then measured by confocal microscopy, as changes in the intensity of fluorescence of the mitochondria-specific dye (DASPI) and the cationic fluorescent markers (Rhodamine 123 and TMRE). DASPI fluorescence was found to be twice as intense in cells from larvae at 17 compared to those at 12°C, indicating that a small increment in incubation temperature has a highly significant effect on mitochondrial protein content. Electron microscopy, which has revealed that the size of mitochondria and the relative area which they occupy in chloride cells is greatest in larvae incubated at the highest temperature, also tends to support this conclusion. The influence of salinity on DASPI fluorescence was found to be highly temperature dependent. At 12°C salinity had little effect, but at 17°C DASPI fluorescence was highest at 44 ppt, showing a strong salinity effect on the mitochondrial protein content in chloride cells at higher temperatures. Salinity and temperature had significant effects on the fluorescence of the cationic marker Rhodamine 123 in chloride cells, indicating adjustments in metabolic rate and implying adaptive adjustment in salt secretory activity. Furthermore estimates of mitochondrial membrane potentials were found to be significantly influenced by temperature, with the lowest values obtained in the lowest temperature. It is concluded that increase in temperature and salinity of incubation, both of which increase osmotic stress in marine fish larvae, induce adaptive changes in the mitochondria of salt-excreting cells.

Keywords
Temperature; salinity; mitochondria; confocal microscopy chloride cells; fish larvae

Journal
Journal of Thermal Biology: Volume 20, Issue 1-2