Properties of the Chlorella receptor for the virus PBCV-1

The virus PBCV-1 attached rapidly, specifically, and irreversibly to the external surface of cell walls of its host, a unicellular, eukaryotic Chlorella-like green alga. Attachment was pH and salt dependent. Each cell contained at least 5 X 10(4) PBCV-1 binding sites and Scatchard analysis indicated that each cell could adsorb 5000 PBCV-1 particles. The PBCV-1 receptor was unaffected by extraction with organic solvents, detergents, high salts, or treatment with several proteases as well as the polysaccharide degrading enzymes, cellulase and pectinase. In contrast, acid and alkali treatments of walls at high temperatures and treatment with an enzyme preparation from PBCV-1 lysates destroyed the virus receptor. We suspect that the receptor is a carbohydrate.