First steps of bacteriophage SPP1 entry into Bacillus subtilis

Abstract

The mechanism of genome transfer from the virion to the host cytoplasm is critical to understand and control the beginning of viral infection. The initial steps of bacteriophage SPP1 infection of the Gram-positive bacterium Bacillus subtilis were monitored by following changes in permeability of the cytoplasmic membrane (CM). SPP1 leads to a distinctively faster CM depolarization than the one caused by podovirus ϕ29 or myovirus SP01 during B. subtilis infection. Depolarization requires interaction of SPP1 infective virion to its receptor protein YueB. The amplitude of depolarization depends on phage input and concentration of YueB at the cell surface. Sub-millimolar concentrations of Ca(2+) are necessary and sufficient for SPP1 reversible binding to the host envelope and thus to trigger depolarization while DNA delivery to the cytoplasm depends on millimolar concentrations of this divalent cation. A model describing the early events of bacteriophage SPP1 infection is presented.

First Insights into the Entry Process of Hyperthermophilic Archaeal Viruses

“…Upon the first encounter of a susceptible host, many bacterial viruses initially bind reversibly to the structures on the cell surface and only then commit to the infection by attaching to the cell irreversibly, a stage subsequently followed by delivery of the viral genome into the cell interior (8,21,(43)(44)(45). To test the reversibility of the SIRV2 adsorption, we investigated whether viral particles could be washed off from the host cell surface.…”

The Lactococcal Phages Tuc2009 and TP901-1 Incorporate Two Alternate Forms of Their Tail Fiber into Their Virions for Infection Specialization*

“…The Siphoviridae tail tip is a multiproteinaceous structure responsible for host recognition and the initiation of phage infection. Siphoviridae often possess a central tail fiber suspending from their tail tip known to be essential for various aspects of phage infection such as tail morphogenesis, bacterial adsorption, cell envelope penetration, and directing DNA ejection (3)(4)(5)(6)(7)(8)(9)(10)(11).…”

A non-invasive method for studying viral DNA delivery to bacteria reveals key requirements for phage SPP1 DNA entry in Bacillus subtilis cells

“…The presence of millimolar concentrations of divalent cations is an absolute requirement for SPP1 infection in standard laboratory conditions (LB medium), 10 mM Ca 2 þ yielding optimal efficiency of plating (Santos et al, 1984;Jakutytè et al, 2012). In liquid media, phage irreversible adsorption to wild type B. subtilis is progressively reduced as Ca 2 þ decreases to sub-millimolar concentrations and SPP1 DNA entry is drastically affected (Jakutytè et al, 2012).…”

“…SPP1 adsorption is facilitated when Ca 2 þ ions in the medium are increased from micro-to millimolar amounts. The latter divalent cation concentration is essential for efficient delivery of the phage DNA into B. subtilis (Jakutytè et al, 2012). SPP1 DNA was detected inside B. subtilis 3 min after phage addition and newly synthesized viral DNA 8 min post-infection (Burger and Trautner, 1978;Burger, 1980).…”