Calf thymus dna ct dna

CAPE (97%), CA (98%), FA (98%), EF (98%), caffeic acid methyl ester (CAME) (98%), caffeic acid ethyl ester (CAEE) (98%), calf thymus DNA (ct-DNA), ascorbic acid, and bovine serum albumin (BSA) were purchased from Sigma (St. Louis, MO, USA). Ferric chloride (≥99%), ferrous ammonium sulfate hexahydrate (≥99.5%), and trisodium citrate dihydrate (≥99.5%) were purchased from Sinopharm Chemical Reagent Co., Ltd. Calcein and Calcein-AM were purchased from MedChemExpress (MCE). 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was purchased from DOJINDO Molecular Technologies.

For the DNA binding studies, Calf-thymus DNA (CT-DNA) was purchased from Sigma Aldrich. The lyophilized CT-DNA was dissolved in 10 mM Tris-HCl, pH 7.9, mixed gently and left overnight at 4°C. Then, the concentration of CT-DNA was determined from the absorbance at 260 nm using an extinction coefficient of 6600 M^-1cm^-1. Compounds 2c, 3c, 5b, 6b, CP-31398 and doxorubicin were dissolved in DMSO to a concentration of 8.35 mM, which were then used as the stock solution for the preparation of the various concentrations (25 μM; 12,5 μM; 6 μM) in 1 mL in 10 mM Tris-HCl (pH 7.9). Afterwards, 18 μM CT-DNA was added to the prepared solutions and were incubated for 1.5 h at 37°C with occasional vortexing. Absorption spectra were measured using a Hitachi U-2900 spectrophotometer in range of 200–600 nm. All absorption spectra were imported and compared in OriginPro 8.0. Results are shown in S3 Table.

Calf thymus DNA (CT-DNA) was supplied by Sigma-Aldrich, (St. Louis, MO, USA). The stock solution of DNA was prepared by dissolving 0.25 mg of DNA in 1 mL of phosphate buffer (pH 7.4). The absorption was titrated by keeping the concentrations of CT DNA constant with varying concentrations of the tested compound—50, 40, 30, 20, and 10 µM. The absorption spectra were recorded in the wavelength range of 240–350 nm using PowerWave microplate spectrophotometer with 1-cm path length quartz cuvettes (BioTek Instruments, Winooski, Vermont, USA).

All oligonucleotides used in this study (see the Supplementary Information) were purchased from Invitrogen (China) and Sangon (China). Calf thymus DNA (ctDNA) was purchased from Sigma-Aldrich (Singapore). All the oligonucleotides and ctDNA were dissolved in relevant buffer. Their concentrations were determined from the absorbance at 260 nm, respectively on the basis of respective molar extinction coefficients using NanoDrop 1000 Spectrophotometer (Thermo Scientific, USA). To obtain G-quadruplex formation, oligonucleotides were annealed in relevant buffer containing KCl by heating to 95 °C for 5 min, followed by gradual cooling to room temperature. The oligonucleotides were engaged in G-quadruplex formation, as determined by circular dichroism (CD) measurements. Stock solutions of compounds (10 mM) were dissolved in DMSO and stored at −80 °C. Further dilutions of samples to working concentrations were made with relevant buffer immediately prior to use.

The chemicals ethyl gallate, bovine serum albumin (BSA) and Calf thymus DNA (CT-DNA) were purchased from Sigma-Aldrich Chemical Co (St Louis, MO. USA). pBR322 DNA was purchased from GENEI (Bangalore, India). Biochemical kits were obtained from Span diagnostics (Surat, Gujarat, India), and all other reagents used were of analytical grade.

Carminic acid and Al₂(SO₄)₃ (analytical standard) were purchased from Sigma-Aldrich and used as received. Calf thymus DNA (ct-DNA) and poly(dG-dC).poly(dC-dG) (pGC.pCG) were purchased from Sigma Aldrich. D-glucose (Glu) powder was purchased from ThermoFisher and used as received. Dried and grinded cochineal insects employed in the dyeing wool-cochineal process were purchased from Telasybastidores (Pertoca—Valparaíso Region, Chile). The stock solutions were prepared in ultrapure water (conductivity 18,2 µS/cm). Commercial white wool was purchased from a textile shop in Madrid, and it was used for the dying process without any treatment and used as received. Silver nitrate, trisodium citrate and absolute ethanol were purchased from Merck, while hydroxylamine hydrochloride and hydroxylamine solution (50% w/w in water) were purchased from Sigma Aldrich. The thin sheet of gold was specially prepared in the facilities at the Faculty of Physical and Mathematical Science (University of Chile) in order to perform the Raman measurements of Carminic acid and Glu. Archaeological samples correspond to the Formative Period of the Arica Culture and were provided by the Museo Chileno de Arte Precolombino in Santiago de Chile.