Format

Send to:

Choose Destination
See comment in PubMed Commons below
Front Microbiol. 2014 Jan 13;4:417. doi: 10.3389/fmicb.2013.00417. eCollection 2014.

Phages of non-dairy lactococci: isolation and characterization of ΦL47, a phage infecting the grass isolate Lactococcus lactis ssp. cremoris DPC6860.

Author information

  • 1Department of Food Biosciences, Teagasc Food Research Centre Fermoy, Ireland ; Department of Microbiology, University College Cork Co. Cork, Ireland.
  • 2Department of Food Biosciences, Teagasc Food Research Centre Fermoy, Ireland.
  • 3Department of Microbiology and Biotechnology, Max Rubner-Institut, Federal Research Institute of Nutrition and Food Kiel, Germany.
  • 4Department of Biological Sciences, Cork Institute of Technology Co. Cork, Ireland.
  • 5Department of Microbiology, University College Cork Co. Cork, Ireland.

Abstract

Lactococci isolated from non-dairy sources have been found to possess enhanced metabolic activity when compared to dairy strains. These capabilities may be harnessed through the use of these strains as starter or adjunct cultures to produce more diverse flavor profiles in cheese and other dairy products. To understand the interactions between these organisms and the phages that infect them, a number of phages were isolated against lactococcal strains of non-dairy origin. One such phage, ΦL47, was isolated from a sewage sample using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. Visualization of phage virions by transmission electron microscopy established that this phage belongs to the family Siphoviridae and possesses a long tail fiber, previously unseen in dairy lactococcal phages. Determination of the lytic spectrum revealed a broader than expected host range, with ΦL47 capable of infecting 4 industrial dairy strains, including ML8, HP and 310, and 3 additional non-dairy isolates. Whole genome sequencing of ΦL47 revealed a dsDNA genome of 128, 546 bp, making it the largest sequenced lactococcal phage to date. In total, 190 open reading frames (ORFs) were identified, and comparative analysis revealed that the predicted products of 117 of these ORFs shared greater than 50% amino acid identity with those of L. lactis phage Φ949, a phage isolated from cheese whey. Despite their different ecological niches, the genomic content and organization of ΦL47 and Φ949 are quite similar, with both containing 4 gene clusters oriented in different transcriptional directions. Other features that distinguish ΦL47 from Φ949 and other lactococcal phages, in addition to the presence of the tail fiber and the genome length, include a low GC content (32.5%) and a high number of predicted tRNA genes (8). Comparative genome analysis supports the conclusion that ΦL47 is a new member of the 949 lactococcal phage group which currently includes the dairy Φ949.

KEYWORDS:

Lactococcus lactis; genome; non-dairy; phage; tail fiber

PMID:
24454309
[PubMed]
PMCID:
PMC3888941
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Frontiers Media SA Icon for PubMed Central
    Loading ...
    Write to the Help Desk