Isolation and characterization of a moderately halophilic Marinobacter phage-host system from the Arabian Sea

• Published in: Environmental monitoring and assessment Vol. 192; no. 3; p. 199
• Main Authors: Aparna, Sreekumar, Parvathi, Ammini, Kaniyassery, Arya
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-03-2020; Springer Nature B.V
• Subjects: Adsorption; Aquatic habitats; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Bacteriophages; Base Composition; Burst size; Cell culture; DNA, Bacterial; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring; Environmental science; Fatty Acids; Genomes; Growth rate; Host range; Hydrocarbon-degrading bacteria; Hydrocarbons; Influence; Latent period; Marinobacter; Microbiological strains; Monitoring/Environmental Analysis; Morphology; Oceans; Phages; Phylogenetics; Phylogeny; Plaques; Radiation; RNA, Ribosomal, 16S; rRNA 16S; Salinity; Sequence Analysis, DNA; Sodium chloride; Surface water; Viruses; Arabian Sea; Marine virus; Burst size; Nitrate; Latent period; Phage-host interactions
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-020-8166-9

Marinobacter
is an ecologically important genus of Gammaproteobacteria found in diverse marine habitats, many species of which are capable of degrading hydrocarbons. In this study, we isolated a
Marinobacter
phage-host system from the surface waters of the Arabian Sea using enrichment culture methods, studied their growth characteristics and investigated the effect of salinity and nitrate concentrations on phage-host interactions. The bacterial isolate had maximum identity to
Marinobacter salsuginis
based on 16S rRNA similarities and was termed as
Marinobacter
sp., strain D1S9. It could tolerate up to 14% of NaCl with maximum growth at 11% NaCl. The host grew optimally between 35 and 40 °C and at pH 8. It had a generation time of 3.7 h with a mean growth rate of 0.27 h
−1
. The phage infected the host forming clear, round plaques of 1–2 mm diameter. It had a narrow host range restricted to the strain
Marinobacter
D1S9. The latent period and burst size of the phage were estimated to be 30 min and 106 phages per infected cell, respectively. The phage had an adsorption rate of 3.4 × 10
−8
 ml min
−1
and retained 40.4% of its adsorption efficiency at 16% NaCl with a maximum at 4% NaCl (76.1%). Inorganic nitrate was found to have a direct role in controlling host growth and phage burst size.