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

Stella EJ, Franceschelli JJ, Tasselli SE, Morbidoni HR - PLoS ONE (2013)

Bottom Line: 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.In summary, we report here the isolation and preliminary characterization of mycobacteriophages that bring new information to the field.

View Article: PubMed Central - PubMed

Affiliation: Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina.

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.

Show MeSH

Related in: MedlinePlus

Phylogenetic analysis of mycobacteriophage partition proteins present in plasmids (pTAR, pTiC58, F, pRA2), non-mycobacterial bacteriophages (P1, N15, LE1) and mycobacteriophages.The neighbourjoining (NJ) tree was obtained with the MEGA5 software using an output from an alignment in ClustalW; bootstrap values from 1000 iterations are shown for ParA (A) and ParB (B) proteins.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585329&req=5

pone-0056384-g006: Phylogenetic analysis of mycobacteriophage partition proteins present in plasmids (pTAR, pTiC58, F, pRA2), non-mycobacterial bacteriophages (P1, N15, LE1) and mycobacteriophages.The neighbourjoining (NJ) tree was obtained with the MEGA5 software using an output from an alignment in ClustalW; bootstrap values from 1000 iterations are shown for ParA (A) and ParB (B) proteins.

Mentions: Our identification of several parA genes prompted the analysis of their phylogenetic link; the results located the Walker A and B boxes, necessary for ParA function, that are highly conserved in this family of proteins [38], [44] (Fig. 5). Interestingly mycobacteriophage 40AC, which lacks a parB gene but contains a parA gene, does not group with the rest of the mycobacteriophages described, suggesting that it underwent a deletion and entered a lytic way of life at a distant evolutionary point (Fig. 6A).


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

Stella EJ, Franceschelli JJ, Tasselli SE, Morbidoni HR - PLoS ONE (2013)

Phylogenetic analysis of mycobacteriophage partition proteins present in plasmids (pTAR, pTiC58, F, pRA2), non-mycobacterial bacteriophages (P1, N15, LE1) and mycobacteriophages.The neighbourjoining (NJ) tree was obtained with the MEGA5 software using an output from an alignment in ClustalW; bootstrap values from 1000 iterations are shown for ParA (A) and ParB (B) proteins.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585329&req=5

pone-0056384-g006: Phylogenetic analysis of mycobacteriophage partition proteins present in plasmids (pTAR, pTiC58, F, pRA2), non-mycobacterial bacteriophages (P1, N15, LE1) and mycobacteriophages.The neighbourjoining (NJ) tree was obtained with the MEGA5 software using an output from an alignment in ClustalW; bootstrap values from 1000 iterations are shown for ParA (A) and ParB (B) proteins.
Mentions: Our identification of several parA genes prompted the analysis of their phylogenetic link; the results located the Walker A and B boxes, necessary for ParA function, that are highly conserved in this family of proteins [38], [44] (Fig. 5). Interestingly mycobacteriophage 40AC, which lacks a parB gene but contains a parA gene, does not group with the rest of the mycobacteriophages described, suggesting that it underwent a deletion and entered a lytic way of life at a distant evolutionary point (Fig. 6A).

Bottom Line: 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.In summary, we report here the isolation and preliminary characterization of mycobacteriophages that bring new information to the field.

View Article: PubMed Central - PubMed

Affiliation: Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina.

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.

Show MeSH
Related in: MedlinePlus