Characterization of damage on Listeria innocua surviving to pulsed light: Effect on growth, DNA and proteome

• Published in: International journal of food microbiology 2018-11, Vol.284, p.63-72
• Main Authors: Aguirre, Juan Salvador, García de Fernando, Gonzalo, Hierro, Eva, Hospital, Xavier F., Espinosa, Irene, Fernández, Manuela
• Format: Article
• Language: English
• Subjects: Cell culture; Culture media; Cyclobutane; Cyclobutane pyrimidine dimers; Damage assessment; Deoxyribonucleic acid; Dimers; DNA; Fatty acids; Flagellin; Fluence; Glucose metabolism; Growth rate; Lag phase; Light; Light effects; Listeria; Listeria innocua; Metabolism; Microscopy; Nucleotides; Parameters; Proteins; Proteomes; Proteomics; Pulsed light
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2018.07.002

The effect of pulsed light treatment on the lag phase and the maximum specific growth rate of Listeria innocua was determined in culture media at 7 °C. Fluences of 0.175, 0.350 and 0.525 J/cm2 were tested. The lag phase of the survivors increased as fluence did, showing significant differences for all the doses; an 8.7-fold increase was observed at 0.525 J/cm2. Pulsed light decreased the maximum specific growth rate by 38% at the same fluence. Both parameters were also determined by time-lapse microscopy at 25 °C in survivors to 0.525 J/cm2, with an increase of 13-fold of the lag phase and a 45% decrease of the maximum specific growth rate. The higher the fluence, the higher the variability of both parameters was. To characterize pulsed light damage on L. innocua, the formation of dimers on DNA was assessed, and a proteomic study was undertaken. In cells treated with 0.525 J/cm2, cyclobutane pyrimidine dimers and pyrimidine (6–4) pyrimidone photoproducts were detected at 5:1 ratio. Pulsed light induced the expression of three proteins, among them the general stress protein Ctc. Furthermore, treated cells showed an up-regulation of proteins related to metabolism of nucleotides and fatty acids, as well as with translation processes, whereas flagellin and some glucose metabolism proteins were down-regulated. Differences in the proteome of the survivors could contribute to explain the mechanisms of adaptation of L. innocua after pulsed light treatment. •Growth rate and proteome of Listeria innocua survivors to PL were analyzed.•PL decreased maximum specific growth rate and increased lag phase of the survivors.•The growth parameters of PL survivors showed higher variability at higher fluences.•The formation of dimers after PL treatment was confirmed.•PL changed the cytosolic proteins of Listeria innocua survivors.