Characterization of Phage Receptors in Lactic Acid Bacteria

BRIGGILER MARCÓ, M.; REINHEIMER, J.; QUIBERONI, A.

FOOD QUALITY: CONTROL, ANALYSIS AND CONSUMER CONCERNS

Nova Science Publishers, Inc.

Lugar: Hauppauge, New York; Año: 2011; p. 431 - 442

Lactic acid bacteria (LAB) are widely used in food fermentation processes. The LAB starters are primarily used because of their capability to produce lactic acid from lactose, thus carrying out the fermentation process. Also, the decrease of pH is a requirement for the safety of products. Moreover, LAB are involved in the production of aroma compounds contributing with the sensorial characteristics of the products.Amongst the great diversity of LAB genera and species, Lactobacillus plantarum has the advantage of being able to grow in a wide variety of food matrix, thus acting as starter in several fermented products. Also, probiotic properties have been reported for Lactobacillus plantarum strains. Therefore, it could be used as starter/probiotic culture in the production of functional foods. However, it activity could be severely affected by bacteriophage attacks.Phage infection of bacterial cells is the main cause of reduction in acid production or complete starter failure, which generates serious economic losses and might result  in low quality and/or unsafe foods. The first step in the bacteriophage lytic cycle takes place when the phage particle adsorbs to the host cell surface. This interaction is highly specific and dependent on the presence of specific recognition sites called receptors. A successful attachment may then be followed by the injection of the phage nucleic acid into the cell, its intracellular replication and release of phage progeny. The study of the first step in the infection cycle of bacteriophages (adsorption) and, specifically, the characterization of phage receptors are very valuable to develop appropriate and alternative defence tools against their attacks.Whole bacterial cells or purified cell walls are used to carry out characterization of phage receptors. Enzymatic and chemical treatments can be performed on purified cell walls to determine the nature of receptor components. Moreover, if phage receptors are carbohydrates in nature, phage inhibition by several saccharides or desorption and competition assays can be applied to determine the compounds involved.In this chapter, several methodologies to determine the nature of phage receptors are reviewed. Particularly, data obtained on the strain Lactobacillus plantarum ATCC 8014 and using these methodologies are detailed and compared with those reported previously for other LAB.