Analysis of novel mycobacteriophages indicates the existence of different strategies for phage inheritance in mycobacteria

PLoS One. 2013;8(2):e56384. doi: 10.1371/journal.pone.0056384. Epub 2013 Feb 28.

Abstract

Mycobacteriophages have been essential in the development of mycobacterial genetics through their use in the construction of tools for genetic manipulation. Due to the simplicity of their isolation and variety of exploitable molecular features, we searched for and isolated 18 novel mycobacteriophages from environmental samples collected from several geographic locations. Characterization of these phages did not differ from most of the previously described ones in the predominant physical features (virion size in the 100-400 nm, genome size in the 50-70 kbp, morphological features compatible with those corresponding to the Siphoviridae family), however novel characteristics for propagation were noticed. Although all the mycobacteriophages propagated at 30°C, eight of them failed to propagate at 37°C. Since some of our phages yielded pinpoint plaques, we improved plaque detection by including sub-inhibitory concentrations of isoniazid or ampicillin-sulbactam in the culture medium. Thus, searches for novel mycobacteriophages at low temperature and in the presence of these drugs would allow for the isolation of novel members that would otherwise not be detected. Importantly, while eight phages lysogenized Mycobacterium smegmatis, four of them were also capable of lysogenizing Mycobacterium tuberculosis. Analysis of the complete genome sequence obtained for twelve mycobacteriophages (the remaining six rendered partial genomic sequences) allowed for the identification of a new singleton. Surprisingly, sequence analysis revealed the presence of parA or parA/parB genes in 7/18 phages including four that behaved as temperate in M. tuberculosis. In summary, we report here the isolation and preliminary characterization of mycobacteriophages that bring new information to the field.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Antitubercular Agents / pharmacology
  • Cations / metabolism
  • Computational Biology
  • DNA, Viral
  • Gene Order
  • Genome, Viral
  • Isoniazid / pharmacology
  • Molecular Sequence Data
  • Mycobacteriophages / classification
  • Mycobacteriophages / genetics*
  • Mycobacteriophages / isolation & purification
  • Mycobacteriophages / physiology
  • Mycobacterium / virology*
  • Phylogeny
  • Sequence Alignment
  • Viral Plaque Assay
  • Viral Proteins / chemistry
  • Viral Proteins / genetics
  • Viral Tropism
  • Virus Replication / drug effects

Substances

  • Antitubercular Agents
  • Cations
  • DNA, Viral
  • Viral Proteins
  • Isoniazid

Associated data

  • GENBANK/JX899358

Grants and funding

This work was supported by grants (PICT 02337) from the National Agency for Science and Technology Promotion (ANPCyT), Argentina, and the Bill and Melinda Gates Foundation (662 Grnad Challenges Explorations Grant OPP1045751). HRM is a career member of Consejo de Investigaciones de la Universidad Nacional de Rosario (CIUNR), EJS and JJF are Fellows of Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.