ROLE OF MARINE FUNGI IN THE BIOCHEMISTRY OF THE OCEANS. IV. GROWTH RESPONSES TO SEAWATER INORGANIC MACROCONSTITUENTS.

Sguros, Peter L. (University of Miami, Miami, Fla.), and Jacqueline Simms. Role of marine fungi in the biochemistry of the oceans. IV. Growth responses to seawater inorganic macroconstituents. J. Bacteriol. 88:346-355. 1964.-The filamentous ascomycete Halosphaeria mediosetigera and the deuteromycete Culcitalna achraspora were gravimetrically characterized by growth curves in natural and artificial seawater media. Response to growth media employing these diluents was very similar, and stationary phases of both cultures showed autolysis. The organisms grew at all concentrations of seawater, but growth maxima were observed between 20 and 60%. Neither seawater was able to reduce the requirement for yeast extract. Glass-distilled water was slightly better than artificial seawater for the survival of homogenized, washed, resting mycelia over long periods at 4 C. Regardless of suspending medium, this treatment did not appreciably alter the regenerative vigor of inocula. Qualitative and quantitative variations of artificial seawater, without rigid exclusion of inorganic traces from experimental media, demonstrated separate growth requirements for Na, K, Mg, Ca, and SO(4). Only K and Ca appeared nontoxic at seawater concentrations, however. Some evidence of Na antagonism by Mg was obtained. Responses to test ions were best observed in the absence of seawater amounts of NaCl. Reactions of these generically distinct fungi to most experimental manipulations were markedly alike. Both fungi appeared to be appropriately labeled "marine," judging by criteria currently in general use.