Effect of Osmotic Shock on Some Intracellular Solutes in Two Filamentous Fungi

Abstract

SUMMARY: Hypoosmotic and hyperosmotic shock experiments confirmed the importance for osmoregulation in Penicillium chrysogenum and Chrysosporium fastidium of glycerol and the osmoticum used in the medium. Growth ceased following both types of shock treatment for a time, depending on the magnitude of the shock and the species. Regrowth following hypoosmotic shock took place some distance behind burst tips. Following hyperosmotic shock, growth was initiated by branching at the apex, but if the magnitude of the shock was greater than 10 MPa, it did not occur in either species although osmotic adjustment was observed. Shock experiments did not implicate the higher polyols in osmotic adjustment. Hypoosmotic shock to C. fastidium resulted in a rapid loss of all internal solutes, while decrease in glycerol in P. chrysogenum following this treatment was more gradual. Transfer of C. fastidium, a species which does not grow on media of high salt concentration, to isoosmotic KCl did not result in loss of turgor although growth was inhibited. Glucose was lost from the hyphae but K+ and Cl- were taken up.