Abstract
Shewanella is a ubiquitous bacterial genus of aquatic ecosystems, and its bacteriophages are also isolated from aquatic environments (oceans, lakes, ice, and wastewater). In this study, the isolation and characterization of a novel virulent Shewanella phage vB_SspS_KASIA and the identification of three prophages of its host, Shewanella sp. M16, including a mitomycin-inducible Mu-like siphovirus, vB_SspS_MuM16-1, became the starting point for comparative analyses of phages infecting Shewanella spp. and the determination of their position among the known bacterial viruses. A similarity networking analysis revealed the high diversity of Shewanella phages in general, with vB_SspS_KASIA clustering exclusively with Colwellia phage 9A, with which it forms a single viral cluster composed of two separate viral subclusters. Furthermore, vB_SspS_MuM16-1 presented itself as being significantly different from the phages deposited in public databases, expanding the diversity of the known Mu-like phages and giving potential molecular markers for the identification of Mu-like prophages in bacterial genomes. Moreover, the functional analysis performed for vB_SspS_KASIA suggested that, despite the KASIA host, the M16 strain grows better in a rich medium and at 30 °C the phage replication cycle seems to be optimal in restrictive culture conditions mimicking their natural environment, the Zloty Stok gold and arsenic mine.
Highlights
Extremophile and extremotolerant organisms are found in many environments, including toxic waste, acid mine drainage, hypersaline and alkaline lakes, high pressures, polar or hot ecosystems, and arsenic-rich environments
The closest homolog of KASIA_p114 is a putative MTase of Colwellia phage 9A (YP_006489274.1; 38% identity), it is worth noting that this protein showed considerable similarity in terms of its amino acid sequence to Dam-like proteins encoded by the Escherichia viruses T4 (NP_049647.1)
As LB is a nutritionally rich medium, and because its components could potentially limit the adsorption efficiency of the phage, we studied the kinetics of KASIA adsorption to Shewanella sp
Summary
Extremophile and extremotolerant organisms are found in many environments, including toxic waste, acid mine drainage, hypersaline and alkaline lakes, high pressures, polar or hot ecosystems, and arsenic-rich environments. 100 mg/kg in soil and 10 μg/L in freshwater [10] This unique ecosystem is inhabited by various microorganisms that are capable of growing in its specific and nutrient-limited conditions, and are well adapted to elevated concentrations of As and other toxic compounds. They are organized in spatially structured complex systems—biofilms covering the corridor walls and ceiling, and mats at the bottom sediments of mine water [11,12,13]. The KASIA phage is unique, as it is the first virulent Shewanella virus isolated from microbial mats, and because it comes from an ecological niche where the parasite, together with its host, must thrive under multiple extremes.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
