Isolation and characterization of a novel indigenous intestinal N4-related coliphage vB_EcoP_G7C

Abstract

Lytic coliphage vB_EcoP_G7C and several other highly related isolates were obtained repeatedly from the samples of horse feces held in the same stable thus representing a component of the normal indigenous intestinal communities in this population of animals. The genome of G7C consists of 71,759 bp with terminal repeats of about 1160 bp, yielding approximately 73 kbp packed DNA size. Seventy-eight potential open reading frames, most of them unique to N4-like viruses, were identified and annotated. The overall layout of functional gene groups was close to that of the original N4 phage, with some important changes in late gene area including new tail fiber proteins containing hydrolytic domains. Structural proteome analysis confirmed all the predicted subunits of the viral particle. Unlike N4 itself, phage G7C did not exhibit a lysis-inhibited phenotype.

Variations in O-Antigen Biosynthesis and O-Acetylation Associated with Altered Phage Sensitivity in Escherichia coli 4s

“…Therefore, sensitivity to these phages depends on O-antigen synthesis, whereas O-antigen O-acetylation is not involved. The same sensitivity pattern of the 4sI and 4sR mutants was observed for phage Alt63, which is closely related to G7C but has a different allele for the host recognition protein gp63.1 (14). It is noteworthy that this phage showed a significantly reduced efficiency of plating on a wild-type 4s lawn but that mutants of Alt63 that are able to grow on both wild-type strain 4s and the 4sI mutants were obtained (N. S. Prokhorov, unpublished data).…”

“…This appears to be the case for phages G7C, phiKT, LC30/70, and Alt63, studied in this work, of which only G7C requires O-antigen O-acetylation (Table 3). The involvement of specific O-antigen recognition in infection processes can account for the extremely narrow host range of bacteriophage G7C (14).…”

“…In addition to G7C, E. coli 4s was used as a host for the isolation and propagation of several other G7C-related phages (14; A. K. Golomidova, unpublished data). Currently, E. coli 4s remains the only known host for bacteriophage G7C, but despite the extremely narrow host range, G7C-related phages persisted in the same horse population for several years (14). The mechanisms that help G7C avoid extinction despite the small fraction of the total E. coli population that is suitable for its growth are poorly understood (9).…”

“…They are linked to the bulk of the virion via the small N-terminal domain of gp66, which is the only part of the two proteins that is homologous to the N4 protein. An enzymatic (lipase or esterase) activity has been predicted for gp63.1, and it was shown previously that the recombinant protein is able to bind transitionally to the cell surface of G7C-sensitive E. coli strain 4s and to modify it to prevent further binding of the protein or G7C particles (14). These data suggest that the LPS may comprise at least one of the G7C primary receptors, and a deterioration of the complex LPS biosynthesis pathway can result in phage sensitivity alterations.…”

Complete Genome Sequence of the Bacteriophages ECBP1 and ECBP2 Isolated from Two Different Escherichia coli Strains

“…The genome sequences of two bacteriophages had low similarity to each other and showed highly conserved synteny with Escherichia phage vB_EcoP_G7C (9) and Enterobacteria phage phiEco32 (12) for ECBP1 and ECBP2, respectively. The complete genomes of ECBP1 and ECBP2 can provide for understanding the interaction between bacteriophage and E. coli and contribute to the development of the biological control of pathogen.…”