The cellular stress response in fish exposed to salinity fluctuations

Area of Science:

• Environmental Biology
• Aquatic Physiology
• Molecular Biology

Background:

• Salinity stress, caused by rapid or gradual environmental salt concentration changes, impacts aquatic organisms.
• Climate change is altering aquatic salinity through mechanisms like estuarine salinization and ocean surface dilution.
• Fish face physiological challenges when environmental salinity exceeds their tolerance thresholds.

Purpose of the Study:

• To review how fish utilize the conserved cellular stress response (CSR) to cope with diverse salinity stress scenarios.
• To elucidate the role of macromolecular damage as a signal for CSR induction in fish.
• To explore the divergence of CSR mechanisms between euryhaline and stenohaline fish species.

Main Methods:

• Review of existing literature on fish physiology and cellular stress responses.
• Analysis of molecular and physiological mechanisms underlying osmosensing and signal transduction in fish.
• Comparative examination of CSR in euryhaline versus stenohaline fish species.

Main Results:

• Salinity stress leads to macromolecular damage, triggering the CSR in fish.
• The CSR involves macromolecular repair, energy reallocation, cell cycle arrest, and programmed cell death.
• Osmosensing and signal transduction link environmental salinity to adaptive physiological changes.
• CSR broadens salinity tolerance in euryhaline fish but is limited in stenohaline species.

Conclusions:

• The cellular stress response (CSR) is a critical adaptive mechanism for fish facing salinity stress.
• Understanding CSR divergence is key to predicting fish vulnerability to changing hydrospheres.
• This knowledge aids in identifying physiological mechanisms of salt tolerance in fish.