Significance of lysogeny for the metabolism of Desulfovibrio spp. strains isolated from aquatic environments of Georgia.

AIMS: Sulphate-reducing bacteria (SRB) are ecologically important group of anaerobic micro-organisms that can reduce sulphate to form hydrogen sulphide-a toxic gas causing iron corrosion on metal surfaces. In this work, SRB strains were isolated from aquatic environments in the country of Georgia to determine their lysogenicity and the role of temperate phages in host metabolism. METHODS AND RESULTS: SRB strains were isolated in samples from the Black Sea coast of Georgia. Based on their genetic, cytological and physiological properties of bacteria, 10 Georgian isolates were assigned to the genus Desulfovibrio. Temperate bacteriophages were induced from three out of ten strains by UV-exposure. Comparison of metal (Fe and Cr) reduction and utilization of various carbon sources by the wild-type (lysogenic) bacterial strains and their UV-irradiated counterparts was done. CONCLUSIONS: Temperate phage in the cells of SRB could alter significant functions of bacteria and may have a contribution in the acquisition of different traits by SRB. SIGNIFICANCE AND IMPACT OF THE STUDY: This article pointed to a significant role for temperate bacteriophages in the metabolism and metabolic potential of host strains of SRB, which were first isolated from the aquatic environment of Georgia.

Genomic characterization of three novel Basilisk-like phages infecting Bacillus anthracis.

BACKGROUND: In the present study, we sequenced the complete genomes of three novel bacteriophages v_B-Bak1, v_B-Bak6, v_B-Bak10 previously isolated from historical anthrax burial sites in the South Caucasus country of Georgia. We report here major trends in the molecular evolution of these phages, which we designate as "Basilisk-Like-Phages" (BLPs), and illustrate patterns in their evolution, genomic plasticity and core genome architecture. RESULTS: Comparative whole genome sequence analysis revealed a close evolutionary relationship between our phages and two unclassified Bacillus cereus group phages, phage Basilisk, a broad host range phage (Grose JH et al., J Vir. 2014;88(20):11846-11860) and phage PBC4, a highly host-restricted phage and close relative of Basilisk (Na H. et al. FEMS Microbiol. letters. 2016;363(12)). Genome comparisons of phages v_B-Bak1, v_B-Bak6, and v_B-Bak10 revealed significant similarity in sequence, gene content, and synteny with both Basilisk and PBC4. Transmission electron microscopy (TEM) confirmed the three phages belong to the Siphoviridae family. In contrast to the broad host range of phage Basilisk and the single-strain specificity of PBC4, our three phages displayed host specificity for Bacillus anthracis. Bacillus species including Bacillus cereus, Bacillus subtilis, Bacillus anthracoides, and Bacillus megaterium were refractory to infection. CONCLUSIONS: Data reported here provide further insight into the shared genomic architecture, host range specificity, and molecular evolution of these rare B. cereus group phages. To date, the three phages represent the only known close relatives of the Basilisk and PBC4 phages and their shared genetic attributes and unique host specificity for B. anthracis provides additional insight into candidate host range determinants.

Correction to: Genomic characterization of three novel Basilisk-like phages infecting Bacillus anthracis.

Following the publication of this article [1], the authors noted two typographical errors: one in Table 1 with regard to the location of the Basilisk Phage, which was incorrectly captured as "Kutaisis, country of Georgia Utah, USA" but should be "Utah, USA".