Characterization of phage receptors in lactic acid bacteria

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

Food Quality: Control, Analysis and Consumer Concerns

NOVA Publishers

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

Lactic acid bacteria (LAB) are widely used in food fermentation processes. The LABstarters 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 forthe  safety  of  products.  Moreover,  LAB  are  involved  in  the  production  of  aromacompounds contributing with the sensorial characteristics of the products.  Amongst the great diversity of LAB genera and species, Lactobacillus plantarum hasthe advantage of being able to grow in a wide variety of food matrix, thus acting as starterin  several  fermented  products.  Also,  probiotic  properties  have  been  reported  forLactobacillus plantarum strains. Therefore, it could be used as starter/probiotic culture inthe  production  of  functional  foods. However,  it  activity  could  be  severely  affected  bybacteriophage 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  particleadsorbs  to  the host cell surface. This interaction  is highly specific and dependent on  thepresence of specific recognition sites called receptors. A successful attachment may thenbe  followed  by  the  injection  of  the  phage  nucleic  acid  into  the  cell,  its  intracellularreplication and release of phage progeny. The study of the first step in the infection cycleof bacteriophages  (adsorption)  and, specifically,  the characterization of phage  receptorsare  very  valuable  to  develop  appropriate  and  alternative  defence  tools  against  theirattacks. Whole bacterial cells or purified cell walls are used  to carry out characterization ofphage  receptors. Enzymatic  and  chemical  treatments  can be performed on purified  cellwalls  to determine  the nature of  receptor components. Moreover,  if phage  receptors arecarbohydrates  in  nature,  phage  inhibition  by  several  saccharides  or  desorption  andcompetition assays can be applied to determine the compounds involved.In this chapter, several methodologies to determine the nature of phage receptors arereviewed. Particularly, data obtained on  the strain Lactobacillus plantarum ATCC 8014and using these methodologies are detailed and compared with those reported previouslyfor other LAB.