Isolation, growth and genome of the Rhodothermus RM378 thermophilic bacteriophage

• Published in: Extremophiles : life under extreme conditions Vol. 18; no. 2; pp. 261 - 270
• Main Authors: Hjorleifsdottir, Sigridur, Aevarsson, Arnthor, Hreggvidsson, Gudmundur O., Fridjonsson, Olafur H., Kristjansson, Jakob K.
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01-03-2014; Springer Nature B.V
• Subjects: Adaptation, Physiological; Amino Acid Sequence; Bacteria; Base Sequence; Biochemistry; Biomedical and Life Sciences; Biotechnology; Genome, Viral; Genomes; High temperature; Hot Temperature; Life Sciences; Microbial Ecology; Microbiology; Molecular Sequence Data; Morphology; Myoviridae; Myoviridae - genetics; Myoviridae - growth & development; Myoviridae - isolation & purification; Original Paper; Proteins; Rhodothermus; Rhodothermus - physiology; Rhodothermus - virology; Rhodothermus marinus; Space life sciences; Viral Proteins - chemistry; Viral Proteins - genetics; Viral Proteins - metabolism; Bacteriophage; Thermophile; RM378
• ISSN: 1431-0651; 1433-4909
• DOI: 10.1007/s00792-013-0613-x

Several bacteriophages that infect different strains of the thermophilic bacterium
Rhodothermus marinus
were isolated and their infection pattern was studied. One phage, named RM378 was cultivated and characterized. The RM378 genome was also sequenced and analyzed. The phage was grouped as a member of the Myoviridae family with A2 morphology. It had a moderately elongated head, with dimensions of 85 and 95 nm between opposite apices and a 150 nm long tail, attached with a connector to the head. RM378 showed a virulent behavior that followed a lytic cycle of infection. It routinely gave lysates with 10
11
pfu/ml, and sometimes reached titers as high as 10
13
pfu/ml. The titer remained stable up to 65 °C but the phage lost viability when incubated at higher temperatures. Heating for 30 min at 96 °C lowered the titer by 10
4
. The RM378 genome consisted of ds DNA of 129.908 bp with a GC ratio of 42.0 % and contained about 120 ORFs. A few structural proteins, such as the major head protein corresponding to the gp23 in T4, could be identified. Only 29 gene products as probable homologs to other proteins of known function could be predicted, with most showing only low similarity to known proteins in other bacteriophages. These and other studies based on sequence analysis of a large number of phage genomes showed RM378 to be distantly related to all other known T4-like phages.