Papers in the Biological Sciences


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Microbiology Resource Announcements



Copyright © 2022 Gunathilake et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.


Phage SN1 infects Sphaerotilus natans and Pseudomonas aeruginosa strains. Its genome consists of 61,858 bp (64.3% GC) and 89 genes, including 32 with predicted functions. SN1 genome is very similar to Pseudomonas phage M6, which contains hypermodified thymidines. Genome analyses revealed similar base-modifying genes as those found in M6.

Phage SN1 was isolated in 1979 from activated sludge samples obtained from a wastewater treatment plant (Lincoln, Nebraska, USA) using S. natans ATCC 13338 as the host (1, 2). An early study showed that the siphophage SN1 has unusual bases in its genome as confirmed by cellulose thin-layer chromatography (1). Its genomic DNA also showed resistance to type II restriction endonucleases (2). Host range studies indicate that phage SN1 can also infect Pseudomonas aeruginosa strains PAO33 and OT684 (2). Here, phage SN1 was amplified with its host S. natans ATCC 13338 in nutrient broth (3 g/L beef extract, 5 g/L peptone) and agitated at 30°C (2). Cell debris were removed by filtration (0.45 mm) and filtrates were stored at 4°C until use. Phage SN1 also infected P. aeruginosa PAO1 (HER1153) in TSB/TSA medium at 30°C using both plaque assays and lysis of liquid cultures. Species identification of the above two host strains was confirmed by 16S sequencing.