Characterization of a new virulent phage ϕMC1 specific to Microbulbifer strain CMC-5

Abstract

Microbulbifer strain CMC-5, isolated from decomposing seaweeds degrades agar, alginate, carrageenan, chitin, carboxymethyl cellulose and xylan. Using bacterial strain CMC-5 as host, a novel virulent phage, designated ϕMC1 was isolated from the coast of Goa, India. Although ϕMC1 demonstrated cross infectivity with type species of Microbulbifer such as M. agarolyticus JAMBA3T and M. celer KCTC 12973T, it did not infect M. mangrovi KCTC 23483T, M. salipalidus JCM 11542T, M. elongatus DSM 6810T and M. hydrolyticus IRE-31T. The one step growth experiment of ϕMC1 infecting bacterial strain CMC-5 at a multiplicity of infection of 0.1, revealed a latent period of 60 min and a burst size of 180. TEM analysis of ϕMC1 indicated it to be a tailless phage with an icosahedral head having a diameter of 60 ± 1.42 nm. The ds DNA of ϕMC1 was restricted by EcoRI, HindIII and SmaI whereas HaeIII, BamHI, PstI, NotI did not cleave the DNA. The molecular size of ϕMC1 DNA was analyzed by restriction digestion as well as pulsed field gel electrophoresis and was estimated at 48.5 kb. The phage infectivity was adversely affected by organic solvents demonstrating the presence of a lipid membrane. The inhibition of ϕMC1 infectivity by EDTA was abolished by addition of Ca and Mg salts.