Virus-like particles in three species of phytoplankton from San Juan Island, Washington

Abstract

Virus-like particles occurring in Hymenomonas carterae (Haptophyceae), Micromonas pusilla (Prasinophyceae) and Cryptomonas sp. (Cryptophyceae) are reported. The particles found in H. carterae were intranuclear, while those of M. pusilla were located in the cytoplasm. Cryptomonas sp. possessed two types of virus-like particles within a single cell, one type was intranuclear, hexagonal in cross-section and similar to that found in H. carterae and M. pusilla, and the second type was stalked and possessed a swollen head region which contained the nuclear material. These stalked particles were located in membrane-bound vesicles. The possible relationship between these two types of particles is discussed.