Distribution of prophages in the oenococcus oeni species

Oenococcus oeni is the most exploited lactic acid bacterium in the wine industry and drives the malolactic fermentation of wines. Although prophage-like sequences have been identified in the species, many are not characterized, and a global view of their integration and distribution amongst strains is currently lacking. In this work, we analyzed the complete genomes of 231 strains for the occurrence of prophages, and analyzed their size and positions of insertion. Our data show the limited variation in the number of prophages in O. oeni genomes, and that six sites of insertion within the bacterial genome are being used for site-specific recombination. Prophage diversity patterns varied significantly for different host lineages, and environmental niches. Overall, the findings highlight the pervasive presence of prophages in the O. oeni species, their role as a major source of within-species bacterial diversity and drivers of horizontal gene transfer. Our data also have implications for enhanced understanding of the prophage recombination events which occurred during evolution of O. oeni, as well as the potential of prophages in influencing the fitness of these bacteria in their distinct niches.Evolution expérimentale en mileu extrême de la bactérie lactique Oenococcus oeni et applications à la sélection de levains malo-lactiques plus performant

Tolerance to high osmolality of the lactic acid bacterium Oenococcus oeni and identification of potential osmoprotectants.

International audienceGrowth of the lactic acid bacterium Oenococcus oeni under hyperosmotic constraint was investigated in a chemically defined medium. The bacterium could grow on media with an elevated osmolality, preferably below 1.5 Osm kg(-)(1) H(2)O. At osmolalities comprised between 0.6 and 1.5 Osm kg(-)(1) H(2)O, the growth deficit elicited by the sugars glucose and fructose was slightly more severe than with salts (NaCl or KCl). In contrast to what was observed in other lactic acid bacteria, proline, glycine betaine and related molecules were unable to relieve inhibition of growth of O. oeni under osmotic constraint. This was correlated to the absence of sequences homologous to the genes coding for glycine betaine and/or proline transporters described in Lactococcus lactis and Lactobacillus plantarum. The amino acid aspartate proved to be osmoprotective under electrolyte and non-electrolyte stress. Examination of the role of peptides during osmoregulation showed that proline- and glutamate-containing peptides were protective under salt-induced stress, and not under sugar-induced stress. Under high salt, PepQ a cytoplasmic prolidase that specifically liberated proline from di-peptides increased activity, while PepX (X-prolyl-dipeptidyl aminopeptidase) and PepI (iminopeptidase) activities were unaffected. Our data suggest that proline- and glutamate-containing peptides may contribute to the adaptation of O. oeni to high salt through their intracellular hydrolysis and/or direct accumulation

Complete genome sequence of lytic Oenococcus oeni bacteriophage OE33PA

Oenococcus oeni is the most common species of lactic acid bacteria associated with malolactic fermentation in wine. Here, we report the genome sequence of the lytic phage OE33PA (vB_OeS_OE33PA). It has a morphotype similar to that of members of the Siphoviridae family, a linear 39,866-bp double-stranded genome with cohesive ends, and 57 predicted open reading frames

“French Phage Network” Annual Conference 2018—Fourth Meeting Report

The present meeting report aims to cover the scientific activities of the 4th French Bacteriophage Network (Phages.fr) symposium which took place during 24th-25th September 2018, at the Agora du Haut-Carré in Talence (France). The hosting institute was University Bordeaux and 72 participants attended the meeting from both public and private sectors, coming from France, Belgium, Ireland, Germany, Portugal and Canada. The scientific program was structured in three themed oral sessions entitled "ecology and evolution", "bacteriophage-host molecular interaction", and "therapy and biotechnology applications" consisting of 21 oral presentations, including three keynote lectures, and a presentation of the activities of the Spanish bacteriophage network. A poster session included 22 presentations

Potential osmoprotectants for the lactic acid bacteria Pediococcus pentosaceus and Tetragenococcus halophila.

Equipe Osmorégulation chez les Bactéries (OB) devenue équipe Dualité ou Universalité de l'Adaptation Lors d'un Stress (DUALS)International audienceThe physiological responses of the lactic acid bacteria Pediococcus pentosaceus and Tetragenococcus halophila (formely known as P. halophila), subjected to osmotic stress in the presence of molecules known to act as osmoprotectants for other bacteria were studied. In a defined medium, glycine betaine, dimethylsulfonioacetate, choline, proline and L-carnitine were able to relieve inhibition of growth at 0.8 M NaCl. The five compounds were shown to efficiently compete with glycine betaine transport, suggesting the existence of common transporter(s) for these molecules. T. halophila, the most tolerant strain, exhibited a larger spectrum of compatible solutes including dimethylsulfonioacetate, dimethylsulfoniopropionate and ectoine. Preliminary data suggest that restoration of growth by ectoine under osmotic constraint seems specific to the genus Tetragenococcus

Bacteriophage GC1, a novel tectivirus infecting gluconobacter cerinus, an acetic acid bacterium associated with wine-making

The Gluconobacter phage GC1 is a novel member of the Tectiviridae family isolated from a juice sample collected during dry white wine making. The bacteriophage infects Gluconobacter cerinus, an acetic acid bacterium which represents a spoilage microorganism during wine making, mainly because it is able to produce ethyl alcohol and transform it into acetic acid. Transmission electron microscopy revealed tail-less icosahedral particles with a diameter of similar to 78 nm. The linear double-stranded DNA genome of GC1 (16,523 base pairs) contains terminal inverted repeats and carries 36 open reading frames, only a handful of which could be functionally annotated. These encode for the key proteins involved in DNA replication (protein-primed family B DNA polymerase) as well as in virion structure and assembly (major capsid protein, genome packaging ATPase (adenosine triphosphatase) and several minor capsid proteins). GC1 is the first tectivirus infecting an alphaproteobacterial host and is thus far the only temperate tectivirus of gram-negative bacteria. Based on distinctive sequence and life-style features, we propose that GC1 represents a new genus within the Tectiviridae, which we tentatively named Gammatectivirus. Furthermore, GC1 helps to bridge the gap in the sequence space between alphatectiviruses and betatectiviruses