4 6 diamidino 2 phenylindole dapi dye

Hep3B and Huh1 cells were seeded onto Poly-lysine (P4707, Millipore Sigma, Darmstadt, Germany) coated cover glasses. 1–2 days later, cells were washed with PBS three times at room temperature and then fixed with 4% paraformaldehyde Fix Solution (Cat: E672002, Sangon, Shanghai, China) for 15 min. Next, the fixed cells were permeabilized with 0.2% Triton X-100 (Cat: E-IR-R122, Elabscience Biotechnology, Wuhan, China) for 10 min at room temperature. Sections were incubated with Ki67 (Cat: 27,309–1-AP, Proteintech, Rosemont, USA) or β-catenin (Cat: #8480, CST) primary antibodies at 4ºC overnight. The next day, sections were washed using PBS for 3 × 5 min at room temperature, and then incubated with 4',6-diamidino-2-phenylindole (DAPI) dye (Cat: D1306, ThermoFisher Scientific, Waltham, MA, USA) and fluorophore-conjugated secondary antibodies at room temperature for 2 h. Images were captured by the Leica microscope.

Cells were seeded onto Poly-lysine (cat: P4707, Millipore Sigma, Darmstadt, Germany) coated cover glasses. 1–2 days later, cells were washed with PBS three times at room temperature and then fixed with 4% paraformaldehyde Fix Solution (cat: E672002, Sangon, Shanghai, China) for 15 min. Next, the fixed cells were permeabilized with 0.2% Triton X-100 (cat: E-IR-R122, Elabscience Biotechnology, Wuhan, China) for 10 min at room temperature. Sections were incubated with γH2AX (cat: ab26350, Abcam Cambridge Science Park, Cambridge, UK) primary antibodies at 4°C overnight. The next day, sections were washed using PBS for 3 × 5 min at room temperature, and then incubated with 4’,6-diamidino-2-phenylindole (DAPI) dye (cat: D1306, ThermoFisher Scientific, Waltham, MA, USA) and fluorophore-conjugated secondary antibodies at room temperature for 2 h. Images were captured by the Leica microscope.

The concentration of monochloramine in water samples was measured using a portable colorimeter (DR900, Hach, Loveland, CO, USA) with monochlor F reagent pillows. A pH meter (SK-620PH, Sato Keiryoki Mfg. Co., Tokyo, Japan) was used to measure the pH of the FS. Surface images of the FO membrane were attained using a scanning electron microscope (SEM) (Tabletop Microscope TM3030Plus, Hitachi High-Technologies, Tokyo, Japan). Bacterial counts in feed solutions were determined using a fluorescence microscope (Shibasaki, Inc., Chichibu, Japan). Each sample was first diluted 200–20,000 times using microfiltration (MF) membrane-treated pure water. Thereafter, 1 mL of the diluted sample was filtered using a track-etched polycarbonate MF membrane with a 0.2 µm pore size (Meric, Tokyo, Japan). After staining, the bacterial number deposited on 40% of the filter surface area was measured. Total bacterial counts (both viable and nonviable bacteria) were measured by staining with 4′-6-diamidino-2-phenylindole (DAPI) dye (Thermo Fisher Scientific, Waltham, MA, USA). Viable bacterial counts were calculated by deducting counts of dead (inactivated) bacteria determined by staining with 3,6-bis(dimethylamino)acridine hydrochloride solution (Dojindo Laboratories, Kumamoto, Japan) from total bacterial counts.

Paeonol (purity ≥98%) was purchased from Chengdu Pulis Biological Science and Technology Co. Ltd. (Chengdu, China). Stock solutions of paeonol were dissolved in ddH₂O at final concentrations of 5 mg ml⁻¹ and kept at −20°C. SYTO 9, FUN^® 1, Calcofluor^® White M2R stain (CWS), Film Tracer SYPRO Ruby (SYPRO Ruby), wheat germ agglutinin (WGA), propidium iodide (PI), and 4′,6-diamidino-2-phenylindole (DAPI) dye were purchased from Invitrogen (Thermo Fisher Scientific, Waltham, Massachusetts, USA). Gatifloxacin was obtained from Shanghai Yuanye Bio-Technology Co. Ltd. (Shanghai, China). Other chemicals used were of analytical grade or better.