New modes of bacteriophage spread discovered

Bacteriophages (phages) are probably the most abundant entities in nature, often exceeding bacterial densities by an order of magnitude. As viral predators of bacteria, phages have a major impact on bacterial communities by reducing some bacteria and enabling others to flourish. Phages also occasionally package host DNA and deliver it to other bacteria, in a process known as horizontal gene transfer (HGT).The biology of phage infection has been extensively studied since the beginning of the 20th century. However, the fate of phages in complex bacterial communities resembling their natural ecosystem has not been studied at the cellular level. To investigate the biology of phage infection in complex bacterial communities, researchers followed phage dynamics in communities harboring phage-resistant (R) and phage-sensitive (S) bacteria, a common scenario in nature.In a research published recently in Cell, Prof. Sigal Ben-Yehuda and members of her research group, led by the PhD student Elhanan Tzipilevich, provided the first demonstration of a mechanism by which bacteria entirely resistant to a given phage become susceptible to it upon co-incubation with sensitive bacteria.The research shows how phage-sensitive bacteria harboring phage receptor can deliver the receptor to nearby phage-resistant cells that lack the phage receptor, via a molecular transfer they call ""acquisition of sensitivity"" (ASEN). This process involves a molecular exchange driven by membrane vesicles (MVs), in which phage-resistant cells transiently gain phage attachment molecules released from neighboring phage-sensitive cells. By exploiting this novel delivery system, phages can invade bacteria lacking their receptor.This mechanism enables phages to expand their host range and deliver DNA into new species, thus facilitating the attachment of phages to non-host species, providing an as-yet unexplored route for horizontal gene transfer (HGT)To view thefull article at Cell