Complete Genome Sequence of SfII, a Serotype-Converting Bacteriophage of the Highly Prevalent Shigella flexneri Serotype 2a

George, Divya; Stephenson, David P.; Tran, Elizabeth Ngoc Hoa; Morona, Renato; Verma, Naresh K.

doi:10.1128/genomea.00626-13

Cited by 7 publications

(4 citation statements)

References 7 publications

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“…Adding an O-acetyl group to Rha I at position 2 (2-O-acetylation) confers serotypes 1b, 3a, 3b, 4b, and 7b with group factor 6 (6,18,19). Glucosylation is mediated by three genes (gtrA, gtrB, and gtr [type specific]) that are arranged in a single operon known as the gtr cluster, which is encoded by serotype conversion bacteriophages, with 6 such bacteriophages identified to date (SfI, SfIC, SfII, SfIV, SfV, and SfX) (20)(21)(22)(23)(24)(25). 2-O-Acetylation of Rha I is performed by a specific O-acetyltransferase encoded by the gene oac (18,19), which is also carried by the serotype conversion bacteriophage Sf6 (26).…”

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confidence: 99%

Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4- O -Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

et al. 2014

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confidence: 99%

Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4- O -Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

et al. 2014

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“…The [52]) and E. coli K-12 (NCBI Protein accession number P77682 [53]). Black, dark gray, and light gray indicate 100%, 80%, and 60% homology, respectively.…”

Section: Resultsmentioning

confidence: 99%

Identification of Genes Required for Glucan Exopolysaccharide Production in Lactobacillus johnsonii Suggests a Novel Biosynthesis Mechanism

Mayer

D’Amato

Colquhoun

et al. 2020

Appl Environ Microbiol

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Lactobacillus johnsonii FI9785 makes two capsular exopolysaccharides-a heteropolysaccharide (EPS2) encoded by the eps operon and a branched glucan homopolysaccharide (EPS1). The homopolysaccharide is synthesized in the absence of sucrose, and there are no typical glucansucrase genes in the genome. Quantitative proteomics was used to compare the wild type to a mutant where EPS production was reduced to attempt to identify proteins associated with EPS1 biosynthesis. A putative bactoprenol glycosyltransferase, FI9785_242 (242), was less abundant in the Δeps_cluster mutant strain than in the wild type. Nuclear magnetic resonance (NMR) analysis of isolated EPS showed that deletion of the FI9785_242 gene (242) prevented the accumulation of EPS1, without affecting EPS2 synthesis, while plasmid complementation restored EPS1 production. The deletion of 242 also produced a slow-growth phenotype, which could be rescued by complementation. 242 shows amino acid homology to bactoprenol glycosyltransferase GtrB, involved in O-antigen glycosylation, while in silico analysis of the neighboring gene 241 suggested that it encodes a putative flippase with homology to the GtrA superfamily. Deletion of 241 also prevented production of EPS1 and again caused a slow-growth phenotype, while plasmid complementation reinstated EPS1 synthesis. Both genes are highly conserved in L. johnsonii strains isolated from different environments. These results suggest that there may be a novel mechanism for homopolysaccharide synthesis in the Gram-positive L. johnsonii. IMPORTANCE Exopolysaccharides are key components of the surfaces of their bacterial producers, contributing to protection, microbial and host interactions, and even virulence. They also have significant applications in industry, and understanding their biosynthetic mechanisms may allow improved production of novel and valuable polymers. Four categories of bacterial exopolysaccharide biosynthesis have been described in detail, but novel enzymes and glycosylation mechanisms are still being described. Our findings that a putative bactoprenol glycosyltransferase and flippase are essential to homopolysaccharide biosynthesis in Lactobacillus johnsonii FI9785 indicate that there may be an alternative mechanism of glucan biosynthesis to the glucansucrase pathway. Disturbance of this synthesis leads to a slowgrowth phenotype. Further elucidation of this biosynthesis may give insight into exopolysaccharide production and its impact on the bacterial cell.

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“…Of the serotypes examined, SfIV was capable of infecting serotypes: 1a, 1b, 1c, X and Y. This suggests that, in comparison to other morphologically similar Shigella phages, SfIV has a much broader host range than SfI (infects only X and Y serotypes) [ 19 ], and SfII (infects serotypes 3a, 5a and Y), but not SfV which infects seven serotypes (1a, 1b, 2a, 2b, 3b, 4b, and Y) [ 27 ]. Surprisingly, there is very little similarity between the host range of these bacteriophages, with serotype Y being the only common serotype infected by all the four phages.…”

Section: Resultsmentioning

confidence: 99%

Isolation, characterization and comparative genomics of bacteriophage SfIV: a novel serotype converting phage from Shigella flexneri

2013

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BackgroundShigella flexneri is the major cause of shigellosis in the developing countries. The O-antigen component of the lipopolysaccharide is one of the key virulence determinants required for the pathogenesis of S. flexneri. The glucosyltransferase and/or acetyltransferase genes responsible for the modification of the O-antigen are encoded by temperate serotype converting bacteriophage present in the S. flexneri genome. Several serotype converting phages have previously been isolated and characterized, however, attempts to isolate a serotype converting phage which encodes the modification genes of serotypes 4a strain have not been successful.ResultsIn this study, a novel temperate serotype converting bacteriophage SfIV was isolated. Lysogenisation of phage SfIV converted serotype Y strain to serotype 4a. Electron microscopy indicated that SfIV belongs to Myoviridae family. The 39,758 bp genome of phage SfIV encompasses 54 open reading frames (orfs). Protein level comparison of SfIV with other serotype converting phages of S. flexneri revealed that SfIV is similar to phage SfII and SfV. The comparative analysis also revealed that SfIV phage contained five proteins which were not found in any other phages of S. flexneri. These proteins were: a tail fiber assembly protein, two hypothetical proteins with no clear function, and two other unknown proteins which were encoded by orfs present on a moron, that presumably got introduced in SfIV genome from another species via a transposon. These unique proteins of SfIV may play a role in the pathogenesis of the host.ConclusionsThis study reports the isolation and complete genome sequence analysis of bacteriophage SfIV. The SfIV phage has a host range significantly different from the other phages of Shigella. Comparative genome analysis identified several proteins unique to SfIV, which may potentially be involved in the survival and pathogenesis of its host. These findings will further our understanding on the evolution of these phages, and will also facilitate studies on development of new phage vectors and therapeutic agents to control infections caused by S. flexneri.

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Complete Genome Sequence of SfII, a Serotype-Converting Bacteriophage of the Highly Prevalent Shigella flexneri Serotype 2a

Abstract: SfII is a serotype-converting temperate bacteriophage of the highly prevalent Shigella flexneri serotype 2a. We isolated the SfII phage from a wild-type strain of S. flexneri serotype 2a. Here, we present the complete genome sequence of this phage.

Cited by 7 publications

References 7 publications

Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4- O -Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4- O -Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

Identification of Genes Required for Glucan Exopolysaccharide Production in Lactobacillus johnsonii Suggests a Novel Biosynthesis Mechanism

Isolation, characterization and comparative genomics of bacteriophage SfIV: a novel serotype converting phage from Shigella flexneri

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