## 3 Results
### Sensitivities to Different UV Wavelengths  
To investigate relative sensitivities to different wavelengths of UV irradiation, the six mutants selected were irradiated with UVA, UVB, or UVC, and the survival ratios were measured. All of the six mutants were more sensitive to the lethal impact of UVA irradiation than the WT; their sensitivities to UVB and UVC could not be distinguished from those of the WT (Figure 3). From these results, we conclude that the UV sensitivities of the mutants _VP0097_, _VP3069_, _VP0136_, _VP0315_, _VP3075_, and _VP0140_ might be restricted to UVA-associated wavelengths. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Genes** & **Orthologous Genes** & **Product** & **Functional Classification** \\ \hline VP3075 & \(\mathrm{atpB}\) & ATP synthase \(\mathrm{F_{0}F_{1}}\) subunit alpha & Oxidative phosphorylation \\ VP3069 & \(\mathrm{atpD}\) & ATP synthase \(\mathrm{F_{0}F_{1}}\) subunit beta & F-type \(\mathrm{H^{+}}\)-transporting ATPase \\ VP0136 & \(\mathrm{ggpG}\) & general secretion pathway protein G & Bacterial secretion system \\ VP0140 & \(\mathrm{ggpK}\) & general secretion pathway protein K & Type II secretion system \\ VP0097 & \(\mathrm{ubiB}\) & \(\mathrm{ubiquinone biosynthesis protein}\) & Ubiquitin and other \\ VP0315 & \(\mathrm{ubiX}\) & 3-polyphenyl-4-hydroxybenzoate & Terpenoid-quinone biosynthesis \\  & & carboxy-lyase UbiX & \\ \hline \hline \end{tabular} Note: ATP, adenosine triphosphate.  
\end{table} 
Table 3: Putative product and functional classification of the Ez-Tn5 DHFR-1-inserted genes in highly UVA-sensitive mutants. Figure 2: Map of _Vibrio parahaemolyticus_ genes associated with the highly UVA-sensitive mutants. Arrows indicate open reading frames of _V. parahaemolyticus_ genes. Arrow heads and gray arrows indicate mutant genes associated with high UVA sensitivity; the white arrows denote other genes with Ez-Tn5 DHFR-1-insertions. Evaluation of Intracellular ATP Concentration and Sensitivity to UVA Irradiation in Strains with Mutations in F\({}_{0}\)F\({}_{1}\)-Type ATP Synthase Genes  
To investigate the relationship between sensitivity to UVA and mutations in genes encoding F\({}_{0}\)F\({}_{1}\)-type ATP synthase, we measured the intracellular ATP concentrations in the mutants _VP3069_ and _VP3075_. Intracellular ATP concentrations were significantly lower in both _VP3069_ and _VP3075_ mutants than in the WT (Figure 4a,b). The gene complementation of _VP3069_ (_VP3069_/_VP3069_) or _VP3075_ (_PVP3075_/_VP3075_) restored the intracellular ATP concentrations and decreased UVA sensitivity, although not to the same extent as observed in the WT (Figure 4a). To determine the relationship between the intracellular ATP concentration and UVA sensitivity, both mutant strains were treated with L-serine (Supplementary Material Figure S2) [23]. The 20 mM L-serine treatment increased the intracellular ATP concentrations and decreased the UVA sensitivities in both _VP3069_ and _VP3075_ (Figure 4b,d). These results suggested that intracellular ATP concentrations regulated by F\({}_{0}\)F\({}_{1}\)-type ATP synthase might be associated with sensitivity to UVA. Figure 3: Sensitivities of six _V. parahaemolyticus_ mutants to different wavelengths of UV light. (**a**) Responses to UVA-LED irradiation at 126 kJ/m\({}^{2}\), (**b**) responses to UVB at 0.27 kJ/m\({}^{2}\), (**c**) responses to UVC at 0.063 kJ/m\({}^{2}\). The sensitivities to UV irradiation were presented as a logarithmic (log\({}_{10}\)) analysis of the survival ratio as described in the materials and methods. The detailed emission spectra of UVA-LED, UVB, and UVC are shown in Supplementary Material Figure S1. Values shown are means \(\pm\) SD; n = 3–6, where n = number of independent replicates. * \(p<0.05\) or ** \(p<0.01\) versus WT.