Leibovitz s l 15 medium

U2OS cells used in the initial experiments to determine overall cellular effects of the toxins (Fig. 1 and movie S1) were cultured in Dulbecco’s modified Eagle’s medium (Corning, Corning, NY) supplemented with 1% penicillin-streptomycin (Cytiva/HyClone, Marlborough, MA) and 10% fetal bovine serum (Corning) at 37°C with 5% CO₂ in a humidified incubator. The identity and purity of the U2OS cells were verified by short tandem repeat profiling (amelogenin + nine loci) at the Genomics Shared Resource (Ohio State University Comprehensive Cancer Center, Columbus, OH). XTC cells (a gift from N. Watanabe), which were used for comparison of cellular effects (figs. S1, S3, A and B, and S7), for actin free barbed-end distribution analysis (Fig. 6), and for all single-molecule live-cell experiments, were cultured in 70% Leibovitz’s L-15 medium (HiMedia, Chester, PA) supplemented with 1% penicillin-streptomycin and 10% fetal bovine serum at 23°C without CO₂ equilibration. Both cell lines were mycoplasma negative as determined by polymerase chain reaction (PCR) tests.

Calendula officinalis oil was purchased from AOS Products Private Ltd., Ghaziabad, India. A CuraSpon CS-950 sponge was supplied by CuraMedical B.V., Assendelft, The Netherlands. Ethanol and potassium dihydrogen orthophosphate were purchased from Finar Limited, Ahmedabad, India. Sodium hydroxide pellets were obtained from HiMedia Laboratories Pvt. Ltd., Mumbai, India. Gingival tissue from patients undergoing gingivectomy was used with prior consent to obtain human gingival fibroblast cell lines (hGf). The tissues were anonymized before they were sent for cell culture. These were maintained at the Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India. Dulbecco’s Modified Eagle Medium (DMEM), Leibovitz’s L15 Medium, fetal bovine serum (FBS), and trypsin were obtained from HiMedia Laboratories Pvt. Ltd., Bombay, India. Dimethyl sulfoxide, EDTA, and Ethanol were purchased from Sigma-Aldrich Corporation, St. Louis, MO, USA. All the reagents that were used in the study were of analytical grade.