Understanding and Exploiting Phage-Host Interactions

Abstract

Initially described a century ago by William Twort and Felix d'Herelle, bacteriophages are bacterial viruses found ubiquitously in nature, located wherever their host cells are present. Translated literally, bacteriophage (phage) means 'bacteria eater'. Phages interact and infect specific bacteria while not affecting other bacteria or cell lines of other organisms. Due to the specificity of these phage-host interactions, the relationship between phages and their host cells has been the topic of much research. The advances in phage biology research have led to the exploitation of these phage-host interactions and the application of phages in the agricultural and food industry. Phages may provide an alternative to the use of antibiotics, as it is well known that the emergence of antibiotic-resistant bacterial infections has become an epidemic in clinical settings. In agriculture, pre-harvest and/or post-harvest application of phages to crops may prevent the colonisation of bacteria that are detrimental to plant or human health. In addition, the abundance of data generated from genome sequencing has allowed the development of phage-derived bacterial detection systems of foodborne pathogens. This review aims to outline the specific interactions between phages and their host and how these interactions may be exploited and applied in the food industry.

Keywords: agriculture; bacteriophage; biosensor; detection; endolysin; food-safety; phage–host interactions; receptor binding protein.

Figure 1

Examples of phage families that are grouped on the basis of their genetic material. The current taxonomy comprises of 22 families of bacterial and archaeal families which can be sourced from the International Committee of Taxonomy of Viruses (ICTV) master list [11].

Figure 2

The lytic and lysogenic lifecycles of phages.

Figure 3

Examples of the possible host cell receptors a tailed phage generally may adsorb to on bacteria.

Figure 4

The structural components of a tailed phage depicting the location of the main components of the T4 phage.

Figure 5

The binding of phages to their host cell receptors. The red phage represents the T4 phage, the phage receptor lipopolysaccharide (LPS) (closest to the phage) and OmpC. The S16 phage is represented in purple, its receptors LPS and OmpC are also in purple. iEPS5 phage and its receptor the flagellin are represented in green and the Vi phage and its receptor sugars of the capsule are depicted in yellow.

Figure 6

The components of a biosensor, displaying the various recognition elements that may be attached to the sensors surface.