title: Characterization of three Lactobacillus delbrueckii subsp. bulgaricus phages and the physicochemical analysis of phage adsorption.
abstract: OBJECTIVE
  Three indigenous Lactobacillus delbrueckii subsp. bulgaricus bacteriophages and their adsorption process were characterized.
  
  
  RESULTS
  Phages belonged to Bradley's group B or the Siphoviridae family (morphotype B1). They showed low burst size and short latent periods. A remarkably high sensitivity to pH was also demonstrated. Indigenous phage genomes were linear and double-stranded DNA molecules of approx. 31-34 kbp, with distinctive restriction patterns. Only one phage genome appeared to contain cohesive ends. Calcium ions did not influence phage adsorption, but it was necessary to accelerate cell lysis and improve plaque formation. The adsorption kinetics were similar on viable and nonviable cells, and the adsorption rates were high between 0 and 50 degrees C. SDS and proteinase K treatments did not influence the phage adsorption but mutanolysin and TCA reduced it appreciably. No significant inhibitory effect on phage adsorption was observed for the saccharides tested. This study also revealed the irreversibility of phage adsorption to their hosts.
  
  
  CONCLUSIONS
  The study increases the knowledge on phages of thermophilic lactic acid bacteria.
authors.affiliation: Programa de Lactología Industrial, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santa Fe, Argentina. aquibe@fiqus.unl.edu.ar
authors.forename: A
authors.initials: A
authors.lastname: Quiberoni
authors.forename: D
authors.initials: D
authors.lastname: Guglielmotti
authors.forename: A
authors.initials: A
authors.lastname: Binetti
authors.forename: J
authors.initials: J
authors.lastname: Reinheimer
mesh_terms: D000327:Adsorption; D001435:Bacteriophages / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D002118:Calcium / Q000378:metabolism; D002473:Cell Wall / Q000502:physiology; D003470:Culture Media; D004279:DNA, Viral / Q000032:analysis; D005516:Food Microbiology; D005944:Glucosamine / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000821:virology*; D008854:Microscopy, Electron; D012266:Ribose / Q000378:metabolism; D017906:Siphoviridae / Q000302:isolation & purification / Q000502:physiology; D013696:Temperature; D015014:Yogurt / Q000821:virology
chemical_list: D003470:Culture Media; D004279:DNA, Viral; D006601:Hexoses; D012266:Ribose; D005944:Glucosamine; D002118:Calcium