Isolation and characterization of marine psychrophilic phage-host systems from Arctic sea ice

Phage-host systems from extreme cold environments have rarely been surveyed. This study is concerned with the isolation and characterization of three different phage-host systems from Arctic sea ice and melt pond samples collected north-west of Svalbard (Arctic). On the basis of 16S rDNA sequences, the three bacteria] phage hosts exhibited the greatest similarity to the species Shewanella frigidimarina (96.0%), Flavobacterium hiberman (94.0%), and Colwellia psychrerythraea (98.4%), respectively. The host bacteria are psychrophilic with good growth at 0degreesC, resulting in a rapid formation of visible colonies at this temperature. The phages showed an even more pronounced adaptation to cold temperatures than the bacteria, with growth maxima below WC and good plaque formation at 0degreesC. Transmission electron microscopy (TEM) examinations revealed that the bacteriophages belonged to the tailed, double-stranded DNA phage families Siphoviridae and Myoviridae. All three phages were host-specific.