Middelboe, M. Marine Biological Laboratory, University of Copenhagen, middelboe@inet.zitech.dk
Hagström, Å. Kalmar University, ake.hagstrom@ng.hik.se

Effects of viruses on the temporal dynamics of four strains of pelagic marine bacteria were followed during the first 250 hours incubation in continuous cultures with artificial seawater. The relative distribution of the bacterial strains in virus-enriched cultures and in control cultures without viruses was determined by plate counts and DNA-DNA hybridization of the specific strains. The abundance of viruses was determined by plaque assay. At the end of the sampling period the bacterial assemblage in the control culture became dominated by a single, fast growing strain; E69 (>90 % of total abundance). In the virus-enriched culture viral lysis caused strong fluctuations in bacterial abundance and in the distribution of the strains relative to the control during the first 50 hours. However, after about 30 hours incubation virus-resistant strains appeared. Consequenly, after about 50 hours incubation in the virus-enriched culture, the population dynamics followed the pattern in the control culture, and the resistant strain of E69 became dominant (> 90 % of total abundance) after about 225 hours. Despite the development of resistant strains, the original, sensitive strains remained present in the culture and co-existed with the resistant strains and sustained a small production of viruses in the culture throughout the experiment.
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
Code: SS40TU1063S