Search results for "prophage"
showing 10 items of 14 documents
Extending the hosts of Tectiviridae into four additional genera of Gram-positive bacteria and more diverse Bacillus species
2017
Abstract Tectiviridae are composed of tailless bacteriophages with an icosahedral capsid and an inner membrane enclosing a double-stranded 15 kb linear DNA genome. Five of the seven previously studied Tectivirus isolates infect bacteria from Bacillus cereus sensu lato group (Betatectivirus), one distantly related member (PRD1) infect Enterobactericeae (Alpatectivirus) and one recently discovered virus infect Gluconobacter cerinus (Gammatectivirus). Here we expand the host spectrum of Betatectivirus elements to four additional genera (Streptococcus, Exiguobacterium, Clostridium and Brevibacillus) and to more distantly related Bacillus species (B. pumilus and B. flexus) by studying the genome…
Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains
2018
Phage therapy is increasingly put forward as a "new" potential tool in the fight against antibiotic resistant infections. During the "Centennial Celebration of Bacteriophage Research" conference in Tbilisi, Georgia on 26-29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as po…
The effect of a temperature-sensitive prophage on the evolution of virulence in an opportunistic bacterial pathogen
2019
AbstractViruses are key actors of ecosystems and have major impacts on global biogeochemical cycles. Prophages deserve particular attention as they are ubiquitous in bacterial genomes and can enter a lytic cycle when triggered by environmental conditions. We explored how temperature affects the interactions between prophages and other biological levels by using an opportunistic pathogen, the bacterium Serratia marcescens, that harbours several prophages and that had undergone an evolution experiment under several temperature regimes. We found that the release of one of the prophages was temperature-sensitive and malleable to evolutionary changes. We further discovered that the virulence of …
Isolation in small populations of Wayampi Amerindians promotes endemicity and homogenisation of their faecal virome, but its distribution is not enti…
2018
The isolated community of the Wayampi Amerindians has been extensively studied for the presence of beta lactamase-producing enterobacteria and their gut microbiota. However, no information about their virome was available. This study tries to establish potential associations between the virome and diverse epidemiological data, through the metagenomic study of the faecal prophages and DNA viruses from 31 samples collected in 2010. Taxonomic assignments, composition, abundance and diversity analyses were obtained to characterise the virome and were compared between groups according to several demographic, environmental and medical data. Prophages outnumbered viruses. Composition and abundance…
CALANGO: a phylogeny-aware comparative genomics tool for discovering quantitative genotype-phenotype associations across species
2023
The increasing availability of high-quality genomic, annotation and phenotypic data for different species contrasts with the lack of general software for comparative genomics that integrates these data types in a statistically sound framework in order to produce biologically meaningful knowledge. In this work, we present CALANGO (Comparative AnaLysis with ANnotation-based Genomic cOmponentes), a first-principles comparative genomics tool to search for annotation terms, such as GO terms or Pfam domain IDs, associated with a quantitative variable used to rank species data, after correcting for phylogenetic relatedness. This information can be used to annotate genomes at any level, including p…
Identification of Gip as a novel phage‐encoded gyrase inhibitor protein of Corynebacterium glutamicum
2021
By targeting key regulatory hubs of their host, bacteriophages represent a powerful source for the identification of novel antimicrobial proteins. Here, a screening of small cytoplasmic proteins encoded by the CGP3 prophage of Corynebacterium glutamicum resulted in the identification of the gyrase-inhibiting protein Cg1978, termed Gip. Pull-down assays and surface plasmon resonance revealed a direct interaction of Gip with the gyrase subunit A (GyrA). The inhibitory activity of Gip was shown to be specific to the DNA gyrase of its bacterial host C. glutamicum. Overproduction of Gip in C. glutamicum resulted in a severe growth defect as well as an induction of the SOS response. Furthermore, …
Cross-reactivity between tumor MHC class I-restricted antigens and an enterococcal bacteriophage
2020
International audience; Intestinal microbiota have been proposed to induce commensal-specific memory T cells that cross-react with tumor-associated antigens. We identified major histocompatibility complex (MHC) class I-binding epitopes in the tail length tape measure protein (TMP) of a prophage found in the genome of the bacteriophage Enterococcus hirae Mice bearing E. hirae harboring this prophage mounted a TMP-specific H-2Kb-restricted CD8+ T lymphocyte response upon immunotherapy with cyclophosphamide or anti-PD-1 antibodies. Administration of bacterial strains engineered to express the TMP epitope improved immunotherapy in mice. In renal and lung cancer patients, the presence of the ent…
Prophages and Past Prophage-Host Interactions Revealed by CRISPR Spacer Content in a Fish Pathogen
2020
The role of prophages in the evolution, diversification, or virulence of the fish pathogen Flavobacterium columnare has not been studied thus far. Here, we describe a functional spontaneously inducing prophage fF4 from the F. columnare type strain ATCC 23463, which is not detectable with commonly used prophage search methods. We show that this prophage type has a global distribution and is present in strains isolated from Finland, Thailand, Japan, and North America. The virions of fF4 are myoviruses with contractile tails and infect only bacterial strains originating from Northern Finland. The fF4 resembles transposable phages by similar genome organization and several gene orthologs. Addit…
Biogenesis and roles of Lacticaseibacillus casei BL23 membrane vesicles
2023
Gram-positive bacteria of the species Lacticaseibacillus casei (formerly known as Lactobacillus casei) are fermentative bacilli found in dairy products that are known for their anti-inflammatory properties and beneficial effects against pathogens. Like all living organisms, L. casei produces nanostructures of 20 to 400 nm in diameter bounded by a lipid membrane called membrane vesicles (MVs). MVs have been shown to contain various cellular constituents and exert multiple functions. However, despite the growing interest in Gram-positive MVs over the past 10 years, the mechanisms of biogenesis and the roles played by these vesicles remain poorly characterized. In this context, the objectives …
Identification of Gip as a novel phage-encoded gyrase inhibitor protein featuring a broad activity profile
2021
AbstractBacteriophages represent a powerful source for the identification of novel antimicrobial proteins. In this study, a screening of small cytoplasmic proteins encoded by the CGP3 prophage of Corynebacterium glutamicum, resulted in the identification of the novel gyrase-inhibiting protein Cg1978 (Gip), which shows a direct interaction with the gyrase subunit A (GyrA). In vitro supercoiling assays further suggest a stabilization of the cleavage complex by Gip. Overproduction of Gip in C. glutamicum resulted in a severe growth defect as well as an induction of the SOS response. The cells adapted to gip overexpression by increasing expression levels of gyrAB and by reducing topA expression…