An epifluorescent microscopy study of enzymatic hydrolysis of fluorescein diacetate associated with the ectoplasmic net elements of the protist Thraustochytrium striatum

Abstract

Thraustochytrium striatum, grown in slide culture, was examined for hydrolytic enzymatic activity using epifluorescence microscopy and fluorescin diacetate. Enzyme activity was noted in the thallus, ecoplasmic nets, and the culture medium when cells were present. Various carbon sources were used to determine the optimal nutritional conditions for enzyme production within the nets. In a seawater medium, glucose and pine pollen provided the best enzyme activity in ecotoplasmic nets, followed by glucose, then sucrose, chitin, carboxymethylcellulose, yeast extract, and yeast nitrogen base. It was concluded that the ecotoplasmic nets contained active hydrolytic enzymes which could be either excreted into the surrounding medium or remain attached to the net surface and thus serve to help degrade complex substrata.