Virus a la sauce Yo-Pro: Microwave-enhanced staining for counting viruses by epifluorescence microscopy

Abstract

A recently developed method for enumerating aquatic viruses (Yo-Pro stained) was modified to reduce staining time and allow counting of fixed samples. Marine and freshwater virus samples to be enumerated were stained with the cyanine-based dye Yo-Pro-1 by using microwave irradiation, which reduced incubation time from 48 h to 4 min. The modified method and the original protocol yielded similar viral estimates. Easier sample handling and the addition of fixed-sample capability should allow epifluorescence counting of viruses to become a routine part of field studies of viral ecology.