Bacterial genomic dna extraction kit

The levels of 8-OHdG in the 0.25 × MIC, 0.5 × MIC, 1 × MIC, 2 × MIC, 4 × MIC, positive, and NC group were determined by the 8-OHdG ELISA kit (Jiangsu Meibiao Biotechnology Co., Ltd., Suzhou, China) [18 (link)]. The MRSA ATCC43300 was cultured at 37 °C and shaken at 180 rpm in MHB. After co-incubation for 8 h, the bacteria were collected by centrifugation (3000 rpm, 15 min, 4 °C) and lysed by ultrasonic waves (200 W, 5 min, 4 °C). The absorbance of the supernatant at 450 nm was used to measure the level of 8-OHdG. Different concentration of 8-OHdG was used to establish the standard curve, then the concentration of 8-OHdG in the sample was calculated by the standard curve.
The levels of DNA damage in the 0.25 × MIC, 0.5 × MIC, 1 × MIC, 2 × MIC, 4 × MIC, positive, and NC group were evaluated by DNA gel electrophoresis [19 (link)]. After co-incubation for 8 h, the bacteria were collected by centrifugation and lysed by the lysozyme, then the total DNA was extracted by the bacterial genomic DNA Extraction Kit (Vazyme Biotech Co., Ltd., Nanjing, China). The extracted DNA was detected by the 1% agarose gel electrophoresis and taken a photo for analysis.

The strains used in standard experiments were cultured under suitable conditions. The DNA was extracted from the bacteria using the bacterial genomic DNA extraction kit (Vazyme Biotech Co., Ltd., Nanjing, China). The concentration and purification of the DNA were examined using a Nanodrop 2000 UV spectrophotometer (Thermo Scientific, Wilmington, NC, USA). Then, the genomic DNA was stored at −20 °C.
The genomic DNA of the artificially contaminated sample was extracted according to our previously established method (CN 105400774 A). The genomic DNA was extracted from a 1000 μL sample solution, and the culture medium was removed by centrifuging the bacteria at 10,760× g for 1 min and then washed thrice with phosphate buffer solution (PBS). Ten microliters of Sodium dodecyl sulfate (SDS, 1%, w/w) were added to the bacterium precipitate and shaken in a vortex for 5 min. Then, the mixture was diluted with 490 μL of double-distilled water and stored at −20 °C.