Modulation of OMV Production by the Lysis Module of the DLP12 Defective Prophage of Escherichia coli K12

Abstract

Outer membrane vesicles (OMVs) are nanostructures mostly produced by blebbing of the outer membrane in Gram negative bacteria. They contain biologically active proteins and perform a variety of processes. OMV production is also a typical response to events inducing stress in the bacterial envelope. In these cases, hypervesiculation is regarded as a strategy to avoid the dangerous accumulation of undesired products within the periplasm. Several housekeeping genes influence the biogenesis of OMVs, including those correlated with peptidoglycan and cell wall dynamics. In this work, we have investigated the relationship between OMV production and the lysis module of the E. coli DLP12 cryptic prophage. This module is an operon encoding a holin, an endolysin and two spannins, and is known to be involved in cell wall maintenance. We find that deleting the lysis module increases OMV production, suggesting that during evolution this operon has been domesticated to regulate vesiculation, likely through the elimination of non-recyclable peptidoglycan fragments. We also show that the expression of the lysis module is negatively regulated by environmental stress stimuli as high osmolarity, low pH and low temperature. Our data further highlight how defective prophages finely contribute to bacterial host fitness.

Bacteriophage Lytic Enzyme P9ly as an Alternative Antibacterial Agent Against Antibiotic-Resistant Shigella dysenteriae and Staphylococcus aureus

“…In line with the virulent feature of PSD9, we did not find lysogeny module in its genome (GenBank numbers: MZ561532.1). In many cases, the lysis module of the bacteriophages is composed of several genes grouped in a single operon, and the endolysin gene often follows a holin gene in the genome ( Pasqua et al, 2021 ). Indeed, a holin gene (ORF57) could be detected in the genome of PSD9.…”

The Role of Temperate Phages in Bacterial Pathogenicity

“…The second pathway is mediated by outer membrane vesicles (OMV), which also can work with prophages [ 67 , 68 ]. OMVs are spherical, bilayer membrane structures directly derived from the outer membrane of Gram-negative bacterial cells.…”

“…OMVs are spherical, bilayer membrane structures directly derived from the outer membrane of Gram-negative bacterial cells. They contain various outer membrane proteins, periplasmic and cytoplasmic proteins, PG, LPS, DNA, RNA, and other enzymes [ 68 ]. The function of OMVs is still under investigation but they are likely to be involved in intercellular communication, DNA transfer, antibiotic resistance, and the release of virulence molecules.…”

“…Additionally, phage-induced lysis is also coordinated with OMV production. Pasqua et al observed that more OMVs were produced when the lytic genes of E. coli K12 prophage DLP12 were not expressed (under the treatments of low pH, high osmolarity, and low temperature); this may result from the accumulated proteins, PG- and LPS- fragments, necessary to be transported out of the cell [ 68 ]. However, the general role of prophages in OMV production and the OMV-associated transport of virulence molecules is still not clear.…”

Bacterial extracellular vesicles: A position paper by the microbial vesicles task force of the Chinese society for extracellular vesicles

“…Pasqua et al used the membrane proteins OmpF and OmpC to relatively quantify the OMVs of E. coli. 190 The team of Hendrix from Ghent University in Belgium combined dimensional rejection chromatography (SEC) and density gradient centrifugation (DG) to separate BEVs from plasma. BEVs were collected at the fifth layer with densities of 1.141-1.186 and then analyzed by western-blot, TEM, and NTA.…”