Phosphate Uptake in an Obligately Marine Fungus II. Role of Culture Conditions, Energy Sources, and Inhibitors

Abstract

Phosphate uptake in the obligately marine fungus, Thraustochytrium roseum, is maximal at pH 7.5 to 7.8, is dependent on temperature, and varies with phosphate concentration. Pyruvate and succinate stimulate phosphate uptake, although they do not increase respiration. The uncoupling agents, 2,4-dinitrophenol and dicoumerol, inhibit phosphate uptake but stimulate oxygen consumption only in the presence of NaCl. Oligomycin inhibits both processes. Among the inhibitors of protein synthesis, chloramphenicol reduces phosphate uptake without affecting respiration. Puromycin is unique in that it greatly enhances phosphate uptake and abolished the lag period associated with this phenomenon. It does not affect respiration. Most fungi isolated from the sea are fortuitous invaders endowed with a broad salinity tolerance which permits them to adapt to a variety of other habitats (28). In contrast, phycomycetes re

Kinetic characterization of the two phosphate uptake systems in the fungus Neurospora crassa

“…There are conflicting reports regarding the number and the kinetic properties of the uptake systems of the yeast Saccharomyces cerevisiae (2,3,8,15). The differences may be due, in part, to differences in the culture conditions before assay, since, in studies with other fungi, phosphate uptake ability has been found to be increased after growth in low-phosphate media (4,27,28). The most extensive study of phosphate uptake by a filamentous fungus has been carried out recently with Neurospora crassa (18)(19)(20).…”

How Do Fungi Survive in the Sea and Respond to Climate Change?

“…In contrast to the mycelial fungi discussed above, there is evidence that zoosporic genera in the Thraustochytriales require sodium chloride for growth. Siegenthaler et al [ 77 , 78 ] suggested that phosphate uptake in Thraustochytrium roseum required sodium chloride. Also, they demonstrated that the presence of the amino acid proline in their cells, as well as high levels of inorganic ions which contribute to the solute potential of the cells.…”