Long-Term Culture of Freshwater Mussel Gill Strips: Use of Serotonin to Affect Aseptic Conditions

Serotonin relaxes the musculature and increases epithelial ciliary activity in freshwater mussel gills. This results in greater than normal water flow through the labyrinth of water canals and channels of the gill. These water spaces harbor significant microbial populations that make aseptic culture of freshwater mussel gills difficult. High concentrations of antibiotics can maintain short-term cultures, but are toxic to the tissue and reduce the lifespan of the culture. Moderate levels of antibiotics used in combination with 0.1 mM serotonin during a single, short pretreatment produces aseptic cultures. These cultures can now be established routinely and are viable for over a month as assayed by gill structural integrity, trypan blue exclusion, leucine incorporation into TCA precipitable protein, and normal physiological responsiveness to serotonin re-exposure.