A sterol glucoside was detected in both myxoamoeboid and plasmodial stages of mating-less mutant,
Colonia strain of
Physarum polycephalum. The isolated substance was characterized and identified as poriferasterol mono-glucoside, which was recently detected in the plasmodia but not in the myxoamoebae of wild-type
Physarum polycephalum.1) The endogenous activity of UDP-glucose: poriferasterol glucosyltransferase, which transfers glucose moiety from sugar nucleotide to poriferasterol and synthesizes poriferasterol monoglucoside, was found in both myxoamoebae and plasmodia of
Colonia strain. This enzyme as well as poriferasterol monoglucoside was detected in the wild-type plasmodia but not in the wild-type myxoamoebae. In wild-type
Physarum, the enzyme was expressed in the process of differentiation from myxoamoebae to plasmodia.2) To clarify the biological roles of poriferasterol monoglucoside in the membrane function, comparative studies of some physiological characteristics were performed. The mutant myxoamoebae showed 5-times higher uptake of D-glucose than wild-type myxoamoebae.
Colonia myxoamoebae could grow in the glucose-based nutrient medium, but in this medium, wild-type myxoamoebae could hardly survive.
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