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Morphological, host range, and genetic characterization of two coliphages
Lawrence Goodridge1, Alicia Gallaccio, Mansel W Griffiths
1Canadian Research Institute for Food Safety, Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Abstract:
Two coliphages, AR1 and LG1, were characterized based on their morphological, host range, and genetic properties. Transmission electron microscopy showed that both phages belonged to the Myoviridae; phage particles of LG1 were smaller than those of AR1 and had an isometric head 68 nm in diameter and a complex contractile tail 111 nm in length. Transmission electron micrographs of AR1 showed phage particles consisting of an elongated isometric head of 103 by 74 nm and a complex contractile tail 116 nm in length. Both phages were extensively tested on many strains of Escherichia coli and other enterobacteria. The results showed that both phages could infect many serotypes of E. coli. Among the enterobacteria, Proteus mirabilis, Shigella dysenteriae, and two Salmonella strains were lysed by the phages. The genetic material of AR1 and LG1 was characterized. Phage LG1 had a genome size of 49.5 kb compared to 150 kb for AR1. Restriction endonuclease analysis showed that several restriction enzymes could degrade DNA from both phages. The morphological, genome size, and restriction endonuclease similarities between AR1 and phage T4 were striking. Southern hybridizations showed that AR1 and T4 are genetically related. The wide host ranges of phages AR1 and LG1 suggest that they may be useful as biocontrol, therapeutic, or diagnostic agents to control and detect the prevalence of E. coli in animals and food.
Insights
Two coliphages, AR1 and LG1, were characterized for their morphology and genetics. Their wide host ranges suggest potential applications in controlling Escherichia coli in animals and food.
Area of Science:
- Microbiology
- Virology
- Genetics
Background:
- Coliphages are viruses that infect bacteria, specifically Escherichia coli.
- Understanding phage characteristics is crucial for potential applications in biotechnology and medicine.
Purpose of the Study:
- To characterize two coliphages, AR1 and LG1, based on their morphology, host range, and genetic properties.
- To assess the potential of these phages as biocontrol or diagnostic agents.
Main Methods:
- Transmission electron microscopy for morphological analysis.
- Host range testing on various Escherichia coli serotypes and other enterobacteria.
- Genome size determination and restriction endonuclease analysis.
- Southern hybridization for genetic relatedness assessment.
Main Results:
- Both AR1 and LG1 belong to the Myoviridae family, with distinct head and tail dimensions.
- Phages demonstrated broad infectivity against multiple E. coli serotypes and some other enterobacteria like Proteus mirabilis, Shigella dysenteriae, and Salmonella.
- Genome sizes were 150 kb for AR1 and 49.5 kb for LG1.
- AR1 shares genetic similarities with phage T4, indicated by restriction enzyme digestion and Southern hybridization.
Conclusions:
- AR1 and LG1 are well-characterized coliphages with significant potential for practical applications.
- Their wide host ranges suggest utility as biocontrol agents against E. coli in food and animal husbandry.
- These phages could also serve as diagnostic tools for detecting E. coli prevalence.