Fastdigest green buffer 10

Agarose gel electrophoresis was performed to detect the ability of DNA degradation of strain zrk13. Briefly, the E. coli genomic DNA/RNA was extracted from overnight cultured E. coli DH5α cells with a Genomic DNA and RNA Kit (Tsingke, China) by omitting the RNA removal step. The reaction system (20 µL) contained 2 µL bacterial supernatant, 2 µL FastDigest Green Buffer (10×) (Thermo Fisher Scientific, USA) and 16 µL E. coli genomic DNA/RNA extracts (2 µg). In parallel, the medium without cells and the supernatant of a Clostridial bacterium were used as the control groups. All bacterial supernatants were obtained by centrifugation with 12,000 g for 10 min from 10-day cultures. Assays were performed at 4 °C for 6 h and 12 h, or 37 °C for 5 min, 10 min, 15 min. Finally, the existence and concentration of genomic DNA/RNA in the reaction solutions were respectively checked by 1% agarose gel electrophoresis at 180 V for 20 min and Nanordrop (IMPLEN, Gemany). The imaging of the gel was taken by the Gel Image System (Tanon 2500, China).

As described previously (5 (link)), agarose gel electrophoresis was performed to detect nucleic acid degradation by strain zrk29. The Escherichia coli genomic DNA and RNA were, respectively, extracted from E. coli DH5α (Tsingke, China) cells using the genomic DNA and RNA Extraction Kits (Tsingke, China) according to the manufacturer’s instructions. The reaction system (10 µL) for this assay contained 4 µL E. coli genomic DNA (1.5 µg), 4 µL E. coli RNA (1.0 µg), 1 µL bacterial spent culture, and 1 µL FastDigest Green Buffer (10×) (Thermo Fisher Scientific, USA). This assay used two control groups: E. coli genomic DNA and RNA degraded by the medium without cells and the culture supernatant of a Clostridia bacterium. The E. coli genomic DNA and RNA degraded by the culture supernatant of strain zrk29 were used as the experimental group. The culture supernatant was obtained by centrifugation with 12,000 × g for 10 minutes. The reactions were conducted either at 37°C for 5 , 15, and 30 minutes or at 4°C for 1, 2, and 3 hours. Finally, the presence of E. coli genomic DNA and RNA in the reaction solutions was detected using 1% agarose gel electrophoresis, run at 180 V for 15 minutes; the concentrations were measured by Nanodrop (IMPLEN, Germany), and gel images were taken using the Gel Image System (Tanon 2500, China).