title: Phages of Lactobacillus casei/paracasei: response to environmental factors and interaction with collection and commercial strains.
abstract: OBJECTIVE
  To investigate the influence of several environmental factors on the viability and cell-adsorption for two Lactobacillus casei/paracasei bacteriophages (PL-1 and J-1).
  
  
  RESULTS
  Both phages showed a remarkably high specificity of species, sharing similar host spectra. Two phages and four sensitive strains were used to conform five phage/strain systems. Each showed a particular behaviour (burst size: ranging from 32 to 160 PFU/infective centre; burst time: 120-240 min and latent time: 5-90 min). For both phages, the viability was not significantly affected from pH 4 to 11 (room temperature) and from pH 5 to 10 (37 degrees C). Adsorption rates were not influenced by calcium ions, but decreased after the thermal inactivation of cells. Adsorption rates were high between 0 and 50 degrees C with maximum values at 30 degrees C and pH 6. System PL-1/Lact. paracasei A showed noticeable differences in comparison with the others, being times required to reach 90% of adsorption of 4 h and lower than 45 min, respectively.
  
  
  CONCLUSIONS
  The data obtained in this work demonstrated that environmental parameters can influence the viability and cell adsorption rates of Lact. casei/paracasei phages. The extent of this influence was phage dependent.
  
  
  CONCLUSIONS
  This work contributes to the enlargement of the currently scarce knowledge of phages of probiotic bacteria.
authors.affiliation: Instituto de Lactología Industrial, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina.
authors.forename: M L
authors.initials: ML
authors.lastname: Capra
authors.forename: A
authors.initials: A
authors.lastname: Quiberoni
authors.forename: J
authors.initials: J
authors.lastname: Reinheimer
mesh_terms: D000327:Adsorption; D001435:Bacteriophages / Q000254:growth & development*; D002118:Calcium / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007780:Lacticaseibacillus casei / Q000821:virology*; D008274:Magnesium / Q000378:metabolism; D011189:Potassium Chloride / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D013045:Species Specificity; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
chemical_list: D012965:Sodium Chloride; D013395:Sucrose; D011189:Potassium Chloride; D008274:Magnesium; D002118:Calcium