Changes in thymidine incorporation by larvae of the American oyster Crassotrea virgim/ca (gmelin) after challenge by two species of yeast (Candida)

Larval cultures of the American oyster Crassostrea virginica were challenged with the yeasts Candida albicans (Robin) and C. tropicalis (Castellani). After 48 hr, microscopic examination revealed abnormal shell development and reduced size for the oyster larvae. The results from autoradiographical studies using 3H leucine indicate that C. albicans and C. tropicalis were ingested by the larvae. Oyster injury caused by the experimental yeasts was determined by measuring 3H thymidine incorporation. During an 8-hr incubation, larvae challenged with various numbers of yeast cells exhibited a 16 to 78% decrease of3H thymidine incorporation compared to unchallenged control oysters. This test provides a simple and rapid measurement of metabolic injury.