Chunnam Techno University is a private technical university in South Korea. Its campus is located in Gokseong County, South Jeolla province. The current president is Cho Sung Soo (조성수)..
While cinnamon essential oil (CEO) is increasingly recognized as a potent natural antimicrobial, its precise multi-target mechanisms against the destructive agricultural pathogen Xanthomonas euvesicatoria remain unclear. This study comprehensively elucidated the physiological, biochemical, and transcriptomic responses of X. euvesicatoria 173 to CEO-induced stress. We investigated its antibacterial efficacy and specific modes of action using microdilution assays, scanning electron microscopy, biochemical viability tracking, and RNAseq. CEO exhibited robust dose-dependent antibacterial activity, with a minimum inhibitory concentration of 400 mg/L and a half-maximal effective concentration (EC50) of 164 mg/L. Analyses revealed that CEO severely compromised cell membrane integrity, leading to a rapid 100-fold increased hypersensitivity to osmotic stress and significant suppression of biofilm formation. Furthermore, sub-lethal CEO exposure induced a severe energy crisis by disrupting membrane-dependent ATP synthesis—measured as a significant reduction in F1F0-ATPase activity—and caused abnormal cellular elongation, indicating cell division arrest. These distinct phenotypes were supported by comparative transcriptomics at the sub-lethal EC50 dose, which revealed 209 highly significant differentially expressed genes (|log2FC| > 3.321). CEO massively downregulated genes associated with the electron transport chain and core energy metabolism (nuo, ndh, cyd, and cyo operons), the ftsZ divisome network, and biofilm-associated type IV pilus and chemotaxis. Conversely, oxidative stress defense genes (kat and ahpD) were upregulated. In conclusion, CEO exerts its bactericidal activity through a synergistic, multi-target action—simultaneously dismantling membrane energetics, inducing severe metabolic suppression, and repressing vital developmental architectures. These findings highlight the significant potential of CEO as a sustainable, resistance-breaking biopesticide for crop protection.
Molybdenum carbide (MoC) thin films were deposited by dual-target magnetron co-sputtering and investigated as platinum-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The effects of Mo target power and film thickness on structural evolution, electrical transport properties, and photovoltaic performance were systematically examined. Raman analysis revealed progressive modifications in the carbon bonding structure, accompanied by variations in the G-band position and an overall reduction in the ID/IG ratio. These structural changes were correlated with increased hardness, reduced electrical resistivity, and decreased surface wettability, indicating improved structural integrity and electrical transport characteristics of the MoC films. The optimized films exhibited a resistivity as low as 2.04 mΩ·cm and improved charge-transport behavior. DSSCs employing the optimized MoC CEs achieved a maximum power conversion efficiency of 4.13%. The photovoltaic performance trends were consistent with the evolution of the electrical transport properties of the MoC thin films, suggesting a close relationship between electrode structure, charge transport, and device operation. The results demonstrate that sputtered MoC thin films are promising functional materials for Pt-free DSSC CEs and provide insight into structure–transport–performance correlations relevant to sustainable photovoltaic energy-conversion systems.
