Physicochemical Analysis of Outer Membrane Vesicles Isolated from Escherichia coli Harboring the Pks Genes

Abstract

Almost all gram‐negative bacteria secrete sphere‐like proteoliposomes named outer membrane vesicles (OMVs). These vesicles provide the bacteria a vehicle for the secretion of outer membrane molecules and periplasmic content. The pks island is a gene cluster present in some strains of bacteria in the human gut microbiota, which has been correlated with the development of colorectal cancer due to the promotion of tumor growth, DNA damage and toxicity in transiently infected eukaryotic cells. The pks island genes encode a sequence of enzymes for the biosynthesis of a compound that we hypothesize is transported from the bacteria to cells by OMVs. The main objective of this investigation is to analyze physically OMVs isolated from E. coli strains harboring and lacking the pks island genes. To achieve this objective, OMVs were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and dynamic light scattering (DLS) to assess any morphological differences between them. Results show that pks+ E. coli strains produce more vesicles than the pks− strain. As expected, vesicle diameters are around 50 – 280 nm. The OMVs from pks+ and pks− strains have similar diameter distribution between them, but markedly different compared against the lab strain DH10B. We conclude that the presence of pks island is associated with events in the production of OMVs but not with the structure and length of them.Support or Funding InformationRISE Program Grant #5R25GM061151‐16This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.