Differences in stress response after UVC or UVA irradiation in Vibrio parahaemolyticus

Abstract

The SOS response is a global regulatory network for repairing DNA damage induced by various environmental stresses such as UV irradiation. The Escherichia coli SOS response has been extensively studied. However, there are no reports on the SOS response in Vibrio parahaemolyticus. In this study, we examined the SOS response in V. parahaemolyticus and compared the differential expression of genes induced by UVC and UVA irradiation. In UVC-exposed wild-type cells, expression of several DNA repair genes was increased. However, expression of these genes was not increased in ΔrecA or lexA mutants. Cell filamentation was observed in wild-type cells, but not in ΔrecA and lexA mutant cells. Sensitivity to UVC was significantly increased in ΔrecA, lexA mutant and Δlon strains compared with wild type. In the case of UVA irradiation, LexA-controlled DNA repair genes were minimally induced and cell filamentation was not observed. Sensitivity to UVA was the same in the mutant and wild-type strains. These findings suggest that there is a RecA-LexA-mediated SOS response in V. parahaemolyticus, and that this response is important to UVC tolerance but does not contribute to UVA tolerance.

Simultaneous Irradiation with Different Wavelengths of Ultraviolet Light has Synergistic Bactericidal Effect on Vibrio parahaemolyticus

“…A lexA mutant was created by a point mutation, amino acid residue Gly89 into Asp89 in the lexA gene (vp2945). The construction of these V. parahaemolyticus mutants were reported previously . Vibrio parahaemolyticus strains were cultured in Luria‐Bertani (LB) broth (1% tryptone, 3% NaCl, 0.5% yeast extract) at 37°C for 15 h. Cells were centrifuged at 7740 × g for 3 min, washed three times with phosphate buffered saline (PBS) (140 m m NaCl, 2.5 m m KCl, 1.6 m m KH 2 PO 4 , 15 m m Na 2 HPO 4 ), and resuspended in PBS.…”

Identification of Outer Membrane Proteins Altered in Response to UVC-Radiation in Vibrio parahaemolyticus and Vibrio alginolyticus

“…This absorption creates damage in the DNA by altering the nucleotide base pairing, thereby creating new linkages between adjacent nucleotides on the same DNA strand [6]. Several investigators have determined the effects of UV radiation on the inhibition of growth [7] and damage of protein, RNA, and DNA for Vibrio [8,9]. All these effects have been related directly or indirectly to genomic damage arising out of primary photochemical changes in nucleic acids.…”

Combined treatment of UVA irradiation and antibiotics induces greater bactericidal effects on <i>Vibrio parahaemolyticus</i>

“…This is the first report on the bactericidal effects of combined UVA irradiation and antibiotic treatment. UVA irradiation indirectly leads to intracellular membrane injury and growth delay by increasing ROS (9,10,16,17). On the other hand, most clinically used antibiotics target cell wall assembly, protein synthesis, or DNA replication.…”

“…We previously established a disinfectant system using a UVA emitting LED (UVA-LED) that has the ability to inactivate pathogenic bacteria (9 -11). UVA induces cellular membrane damage and growth delay (12)(13)(14) indirectly by increasing levels of reactive oxygen species (ROS), including superoxide anion radicals (O 2 -), hydroxyl radicals (OH -), hydrogen peroxide (H2O2), and singlet oxygen ( 1 O2) (9,10,15,16). A UVA-LED sterilization system is easy to combine with other disinfection systems and is more cost effective than the usual UVC method.…”