Caractérisation des particules virales planctoniques dans un lac du Massif Central français : Aspects méthodologiques et premiers résultats

Abstract

In this short communication, we describe a simple method to ultracentrifuge and concentrate planktonic virus-like particles, for their examination with a transmission electron microscope. A description of different morphotypes of particles clearly assimilable to viruses is made in plankton samples from the euphotic layer of a eutrophic lake (Lake Aydat), during its spring and summer development. The particles possess a tail and a 6-sided icosahedral capsid-head, with dimensions similar to those of phages already described in marine systems. The diversity of viral forms and their abundance (10 fold higher than that of bacteria) in Lake Aydat, suggests a significant role in controlling bacterial number in lakes.