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Host modification and restriction with a mycobacteriophage isolated from a pseudolysogenic Mycobacterium chelonei
Abstract:
A pseudolysogenic Mycobacterium chelonei and its phage phi630 are described. Phage phi630 is the first mycobacteriophate reported to be resistant to the nonpolar solvents chloroform, dioxan and diethyl ether. The phage had a latent period of 75 min, a rise period of 90 min and a burst size of 5I. Evidence is presented for host modification and restriction. Phage phi630A, grown on host strain M. chelonei F-630 Rg, plated on the alternative host M. smegmatis ATCC607 with an efficiency of plating (e.o.p.) of 10(-5). Phage phi630B, grown on host M. smegmatis, plated with an e.o.p. of 10(-5) on the alternative host F-630 Rg. Phages phi630A and phi630B absorbed equally well on their alternative hosts and on their indicator host strains. The progeny of plaques from initial platings on the alternative host, when grown in the alternative host, exhibited a marked reduction in e.o.p. on their original host.
Insights
This study describes a novel phage, phi630, from Mycobacterium chelonei, notable for its resistance to common solvents. Evidence suggests this phage exhibits host modification and restriction, impacting its infectivity across different bacterial strains.
Area of Science:
- Microbiology
- Virology
- Bacteriology
Background:
- Pseudolysogeny involving Mycobacterium chelonei and its phage phi630 is detailed.
- Phage phi630 is identified as the first mycobacteriophage demonstrating resistance to nonpolar solvents like chloroform, dioxan, and diethyl ether.
Purpose of the Study:
- To characterize the novel mycobacteriophage phi630.
- To investigate the host modification and restriction phenomena associated with phage phi630.
- To assess the phage's lytic cycle parameters and solvent resistance.
Main Methods:
- Characterization of phage phi630's latent period, rise period, and burst size.
- Testing phage phi630's resistance to nonpolar solvents (chloroform, dioxan, diethyl ether).
- Evaluation of phage-host interactions, including adsorption and efficiency of plating (e.o.p.) on different Mycobacterium strains (M. chelonei and M. smegmatis).
Main Results:
- Phage phi630 exhibited a latent period of 75 min, a rise period of 90 min, and a burst size of 51.
- Phage phi630 demonstrated resistance to chloroform, dioxan, and diethyl ether.
- Evidence of host modification and restriction was observed, with significant reductions in e.o.p. when phages were propagated on alternative hosts.
Conclusions:
- Phage phi630 represents a unique mycobacteriophage due to its solvent resistance.
- The study provides evidence for host-specific modification and restriction mechanisms in phage phi630 infections of Mycobacterium species.
- Further research into phi630 could offer insights into phage-host interactions and potential applications in controlling mycobacterial infections.