A 96-h exposure experiment was conducted to elucidate the toxicity responses of the marine diatom Thalassiosira pseudonana upon exposure to different temperatures and copper (Cu) concentrations. Three Cu treatments (seawater control; 200 μg/L Cu, EC50 for the yield at 25 °C; and 1000 μg/L Cu, EC50 for growth inhibition at 25 °C) were conducted against four temperatures (10 °C, 15 °C, 25 °C and 30 °C). Growth rate and photosynthetic responses showed a significant interacting thermal-chemical effect with strong synergistic responses observed at 30 °C treatments. Expression of heat shock protein (hsp) was positively modulated by increasing temperatures. Hsp 90, hsp90–2 and sit1 (related to silica shell formation) were highly expressed at 30 °C under 1000 μg/L Cu, while the genes encoding light harvesting proteins (3HfcpA and 3HfcpB) and silaffin precursor sil3 were significantly up-regulated at 15 °C under 200 μg/L Cu. Our results indicated an increase Cu toxicity to T. pseudonana under high temperature and Cu dose.
Bibliographical noteFunding Information:
This work is supported by a General Research Fund of Research Grants Council (Project number: 17305715 ) awarded to KMY Leung and two awards of the Small Project Fund from the University of Hong Kong to KMY Leung and PTY Leung, respectively. The authors thank Dr. Edward Lau for proofreading this manuscript.
© 2017 Elsevier Ltd
- Heat shock protein
- Marine diatom
- Thermal stress