title: Expression of Lactobacillus pentosus B96 bacteriocin genes under saline stress.
abstract: This research studied the influence of sodium chloride on bacteriocin activity of table olives' strain Lactobacillus pentosus B96. The strain was cultured in MRS under different NaCl concentrations (0, 4, 6 and 8%, in w/v). In MRS, maximum bacteriocin activity was achieved 9 h later. A medium containing 4 or 6% NaCl (w/v) increased the total bioactivity of the strain and an 8% NaCl reduced it. Real-time PCR was used to monitor the genetic expression of the bacteriocin genes plnA, plnB, plnC, plnE/F, plnJ, plnK, plnN and plantaricin S. Cultured in MRS, plantaricin S reached its maximum expression during the lag phase while plnE/F expresses during the exponential phase. The presence of sodium chloride in the medium moved the maximum expression of plantaricin S to the stationary phase, independently of the concentration. 4% (w/v) of NaCl didn't affect the expression pattern of plnE/F while promotes the expression of plnN during both the lag and the exponential phases. More sodium chloride, 6% (w/v) maintained the expression of plnN in the pag phase but not in the exponential and moved plnE/F expression to the stationary phase. Plantaricin S, plnE/F and plnN over-expressed during the stationary phase in the higher sodium chloride concentration assayed, 8% (w/v). The relative expression level of plsA was 1000-fold higher than that of the plnE/F and plnN genes and even the ldhD constitutive gene used. Under our conditions, expression of plnA, plnB, plnC, plnJ and plnK genes was not observed.
authors.affiliation: Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Hurtado
authors.forename: Cristina
authors.initials: C
authors.lastname: Reguant
authors.forename: Albert
authors.initials: A
authors.lastname: Bordons
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rozès
mesh_terms: D001430:Bacteriocins / Q000235:genetics*; D007778:Lactobacillus / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological
chemical_list: D001430:Bacteriocins; D012965:Sodium Chloride