Impact of the cell life-cycle on bacteriophage T4 infection

Abstract

Synchronized Escherichia coli cultures were infected with bacteriophage T4 at discrete points in the cell growth cycle. The cell cycle had a significant impact on the outcome of infection. Cell burst size was smallest for newly formed cells and increased dramatically as these progressed in the cell cycle. The largest burst sizes were achieved when infecting cells immediately prior to cell division. When cells were infected during cell division, the burst size was reduced back to its initial value. Interestingly, lysis time was longest for young cells, reached a minimum at the same point that burst size reached its maximum value, and then increased at the commencement of cell division. Consequently, phage productivity in cells about to undergo cell division was almost three times greater than the productivity of young, newly formed cells. The availability of intracellular resources is believed to be the major driving force behind phage productivity during infection. Indeed, intracellular RNA contents at the time of infection were found to correlate strongly with phage productivity. There was no significant relationship between cell DNA levels and phage productivity. Finally, burst size experiments suggested that the cell cycle also influenced the likelihood of a phage to undergo productive infection.

Dynamic marine viral infections and major contribution to photosynthetic processes shown by spatiotemporal picoplankton metatranscriptomes

“…Another theory on the timing of infection by cyanomyoviruses is that late infection coincides with the S/G2 phases in the host cell cycle, in which the host genome was already replicated but the cell hasn't divided yet, the logic being that there would be double the amount of nucleotides available for synthesis of phage genomes 63 . This is indeed the case in the T4 phage of Escherichia coli 64 . Evidence from cultures 65,66 and from environmental samples 67 indicate that for at least some strains of Prochlorococcus the host cells divide at dawn, which would imply that the bulk of phage transcription occurs during the night, and may also explain why we were unable to assemble cyanomyovirus genomes from our metatranscriptomes.…”

Regulation of infection efficiency in a globally abundant marine Bacteriodetes virus

“…In contrast, the lack of model systems to study inefficient infections (e.g., those with lower fraction of infected/lysed cells and long latent periods) is problematic, as natural ecosystems are dynamic and environmental conditions impact host diversity, density and/or physiology, as well as the efficiency of phage–host interactions (You et al , 2002; Abedon et al , 2003; Shao and Wang, 2008; Stocker, 2012; Mojica and Brussaard, 2014; Storms et al , 2014; Zeglin, 2015). To date, work on infection efficiencies is mostly theoretical (Abedon et al , 2001; You et al , 2002; Bragg and Chisholm, 2008) and there is a need for new phage—host model systems, particularly those displaying inefficient infections and that are relevant in nature.…”

Diel Infection of Cyanobacteria by Cyanophages

“…Studies on phages infecting Escherichia coli showed that the largest burst size was achieved after the completion of host DNA replication and immediately prior to cell division (Starka, 1962;Storms et al, 2014). This is likely due to the increased availability of intracellular resources for the formation of phage progeny (Storms et al, 2014).…”

“…This is likely due to the increased availability of intracellular resources for the formation of phage progeny (Storms et al, 2014). Under light-dark cycles, S. elongatus PCC 7942 cells divide mainly during the daytime and stop dividing early at night (Mori et al, 1996).…”