ULTRASTRUCTURAL EXAMINATION OF VIRUS-LIKE PARTICLES IN A MARINE RHIZOPOD (SARCODINA, PROTISTA)

Recent research indicates that bacteriophages are abundant and important for controlling populations in prokaryote microbial communities. The number and role of viruses in eukaryotic microbial communities is less well known. This report demonstrates the presence of polyhedral virus-like particles infecting a free-living, marine rhizopod. The virus-like particle appears to cause cell damage and possibly death. It is able to replicate within the protist and may be able to spread to other members of the population. A survey of the literature indicates that viruses and virus-like particles are present in other protists, perhaps more commonly than usually reported. If viruses are widely dispersed in eukaryote microbial populations, they could contribute significantly to cycling in aquatic food webs and have implications for gene transfer between marine organisms.