Subcellular level variation in protein accumulation of the halophylic yeast Debaryomyces hansenii grown under conditions of high osmolarity.
We have analyzed electrophoretic profiles of polypeptides extracted from various cell compartments of the yeast Debaryomyces hansenii, cultured under high osmolarity and under control conditions. We tested the effect of high concentrations of solutes with an osmotic component (sorbitol), and with osmotic and ionic components combined (NaCl or KCl). Densitometric analyses of the extracted polypeptides indicated that the stressing solutes had a differential effect on the relative concentration of total proteins as well as in proteins extracted from three subcellular compartments. Sorbitol caused a significant decrease in the concentration of various polypeptides associated with the mitochondria and the cytoplasm. By contrast, sodium ions elicited marked increases in concentration in four cytoplasmic polypeptides. KCl did not have a major effect in any of the subcellular compartments. Polypeptides were grouped as having a general osmotic response, or as having a response apparently modulated by the particular ionic environment of the growth medium. In all treatments, the number of polypeptides with an increase in their relative concentration was roughly similar to the number of polypeptides with a decrease in concentration, both relative to controls. Our results agree with previous observations on the complexity of the osmoregulatory response involving proteins whose concentration depends on the solute causing the stress. The results also indicate that subcellular compartments respond differently to stressors.
Calderón-Torres
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Unidad Académica Puerto Morelos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Apartado Postal 1152, CP 77500, Cancún, Q.R., México.
Thomé
P E
PE
D003470:Culture Media; D005656:Fungal Proteins / Q000378:metabolism*; D009994:Osmolar Concentration; D011189:Potassium Chloride / Q000494:pharmacology; D004718:Saccharomycetales / Q000254:growth & development* / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013012:Sorbitol / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism*; D014882:Water-Electrolyte Balance
D003470:Culture Media; D005656:Fungal Proteins; D012965:Sodium Chloride; D013012:Sorbitol; D011189:Potassium Chloride