Genetic richness of vibriophages isolated in a coastal environment

Abstract

The purpose of this study was to characterize Vibrio parahaemolyticus viruses (VpVs) isolated from different environments within and adjacent to the Strait of Georgia, and to examine the relative influences of distance and environment on host-range and genetic richness. Nearly all seawater enrichment cultures (29/31) generated isolates, implying that VpVs were widespread in the virioplankton, yet at low abundances (< 1 l(-1)). Viruses were not detected in sediments (n = 99). Fourteen of the 16 viruses characterized were siphoviruses, with genome sizes ranging from approximately 45-106 kb, and half were capable of infecting other Vibrio species. The VpVs infected bacteria isolated from oysters and sediments fairly well (55% and 46% of the host-virus combinations, respectively), but were unable to infect many of the bacteria isolated from the water column (< 13% of 112 combinations). When compared with VpVs from oysters, it was clear that the major determinant of phenotypic (host-range) and genetic richness (by the DP-RAPD assay) was not geography, but the source environment from which the VpVs originated. Therefore, the VpV population within the Strait of Georgia is a highly diverse mixture of phenotypes and genotypes.

La « synergie phages-antibiotiques »

“…Heureusement, les bactéries sont aussi victimes de prédateurs naturels puisque, comme tous les autres organismes vivants, elles peuvent être infectées par des virus. Ces virus de bactéries, les bactériophages ou phages, sont très spécifiques ; ils infectent en général une seule espèce de bactérie et même souvent seulement certaines souches de l'espèce [1,2]. Presque toutes les espèces bactériennes peuvent être infectées par de nombreux phages différents.…”

Viral lysis of Phaeocystis pouchetii: Implications for algal population dynamics and heterotrophic C, N and P cycling

“…As viral lysis may influence phytoplankton population dynamics, algal resistance to viral infection could potentially be an important parameter in the selective forces that contribute to structuring phytoplankton communities. Growing evidence that viral control of bacterial hosts selects for virus-resistant bacteria under controlled conditions in culture experiments (for example, Middelboe, 2000; Middelboe et al, 2001;Mizoguci et al, 2003), have suggested that viral activity contributes to the high clonal diversity often observed in aquatic systems (for example, Comeau et al, 2006;Holmfeldt et al, 2007;Stenholm et al, 2008). Resistance to viral infection has also been demonstrated in populations of cyanobacteria.…”

Large Variabilities in Host Strain Susceptibility and Phage Host Range Govern Interactions between Lytic Marine Phages and Their Flavobacterium Hosts

“…For instance, the single-host enrichment protocol may select for phages with a narrow host range (22,64), and infection and lysis by low-virulence phages, which typically have a broad host range (22), may not be detected in plaque assays (10). However, some marine phages are known to infect different strains of the same species (12,51,64) or even different species (10)(11)(12). Hence, the specificity of phage-host interactions in marine waters needs to be better characterized and understood.…”