ABSTRACT
The ecological significance of virus has been focused in relation to the relative high numbers of viruses or virus-like particles (VLPs) found in aquatic ecosystems. New methods for direct count of viral particles and indirect estimation of viral total count combined with the rapid decay of free viruses have shown that bacterial communities are strongly influenced by viruses. This chapter describes the method used for total virus counts in transmission electron microscopy (TEM). The main advantage of the method is the ability to obtain total counts of viral particles. It is also possible to count the fractions of bacteria which contain mature viral particles, and to make estimates of burst sizes from cells in lysis. Total counts and size distribution of bacteria and flagellates can be estimated from similar preparations as used for virus total counts.
