Ascorbic acid potentiates photodynamic inactivation mediated by octyl gallate and blue light for rapid eradication of planktonic bacteria and biofilms.

This study reported for the first time that Ascorbic acid (AA) could appreciably boost the efficiency of Octyl gallate (OG)-mediated photodynamic inactivation (PDI) on Escherichia coli and Staphylococcus aureus in planktonic and biofilm states. The combination of OG (0.075 mM) and AA (200 mM) with 420 nm blue light (212 mW/cm2) led to a >6 Log killing within only 5 min for E. coli and S. aureus and rapid eradication of biofilms. The mechanism of action appears to be the generation of highly toxic hydroxyl radicals (•OH) via photochemical pathways. OG was exposed to BL irradiation to generate various reactive oxygen radicals (ROS) and the addition of AA could transform singlet oxygen (1O2) into hydrogen peroxide (H2O2), which could further react with AA to generate enormous •OH. These ROS jeopardized bacteria and biofilms by nonspecifically attacking various biomacromolecules. Overall, this PDI strategy provides a powerful microbiological decontamination modality to guarantee safe food products.

A comprehensive evaluation of circ_0065214/ miR-188-3p/GPNMB axis in breast cancer.

CircRNAs are involved in multiple aspects during carcinogenesis, including tumorigenesis, vascularization, apoptosis and others. Exploring the role of circRNAs in breast cancer (BC) enables us to understand the development mechanism of BC more comprehensively. Here, we screened out and verified an up-regulated circRNA in BC from GEO data. Quantitative Real-time PCR (qRT-PCR) showed that circ_0065214 had a high expression level in BC patients. Besides, circ_0065214 had good diagnostic value in BC serum, and the area under the diagnostic curve, sensitivity and specificity were 0.78, 0.63 and 0.85, respectively. The combined application of circ_0065214 with CEA and CA-153 can further improve the diagnostic efficiency. The knockdown of circ_0065214 in vivo and in vitro inhibited the proliferation, migration and invasion of BC, but promoted autophagy. At last, dual-luciferase reporter assay and rescue assays revealed that circ_0065214 acted as a decoy to adsorb miR-188-3p, and then relieved the repressive effect of miR-188-3p on its target GPNMB. Our results demonstrated that circ_0065214 regulated the expression of GPNMB by competitively binding to miR-188-3p, thus promoting the proliferation, migration and invasion of breast cancer cells and inhibiting autophagy. These findings provided an original therapeutic strategy for BC.

Ultraefficient OG-Mediated Photodynamic Inactivation Mechanism for Ablation of Bacteria and Biofilms in Water Augmented by Potassium Iodide under Blue Light Irradiation.

While photodynamic inactivation (PDI) has emerged as a novel sterilization strategy for drinking water treatment that recently attracted tremendous attention, its efficiency needs to be further improved. In this study, we aimed to clarify the ultraefficient mechanism by which potassium iodide (KI) potentiates octyl gallate (OG)-mediated PDI against bacteria and biofilms in water. When OG (0.15 mM) and bacteria were exposed to blue light (BL, 420 nm, 210 mW/cm2), complete sterilization (>7.5 Log cfu/mL of killing) was achieved by the addition of KI (250 mM) within only 5 min (63.9 J/cm2). In addition, at lower doses of OG (0.1 mM) with KI (100 mM), the biofilm was completely eradicated within 10 min (127.8 J/cm2). The KI-potentiated mechanism involves in situ rapid photogeneration of a multitude of reactive oxygen species, especially hydroxyl radicals (•OH), reactive iodine species, and new photocytocidal substances (quinone) by multiple photochemical pathways, which led to the destruction of cell membranes and membrane proteins, the cleavage of genomic DNA and extracellular DNA within biofilms, and the degradation of QS signaling molecules. This multitarget synergistic strategy provided new insights into the development of an environmentally friendly, safe, and ultraefficient photodynamic drinking water sterilization technology.