Microscale mda assay kit

Malondialdehyde (MDA) was determined by the microscale MDA assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China) according to a previously described protocol (Kim et al., 2020 (link)). L. monocytogenes cells were collected by centrifugation at 6,000 rpm for 10 min (10⁶ CFU/ml) and then washed twice with PBS (0.1 M, pH 7.4). Cells treated with different concentrations of moringin (0, 1/2 MIC, 1 MIC, and 2 MIC) were resuspended in PBS and sonicated on ice. The remaining debris was removed by centrifugation at 15,000 rpm at 4°C for 10 min. The supernatant was taken for MDA measurement according to the MDA assay kit’s instructions. The protein content was measured using a total protein quantitative assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China), using bovine serum albumin as the standard.

Algal cells were collected by centrifugation (8000 rpm, 10 min) and resuspended with PBS (0.01 M, pH = 7.4). The algal cells were washed twice with PBS and then homogenized by sonication in an ice bath for 5 min. The homogenate was centrifuged, and the supernatant was collected for further analysis. Proteins were detected using the Coomassie bright blue G-250 method [37 (link)]. The molecular indicator of lipid peroxidation, malondialdehyde (MDA), was evaluated using a microscale MDA assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China) according to the manufacturer’s protocol. The catalase (CAT) activity was measured using a CAT assay kit (Nanjing Jiancheng Bioengineering Institute, China). All biomarker concentrations were normalized to their protein content separately.

Algal cells were collected by centrifugation (8000 rpm, 10 min), and then resuspended in a phosphate buffer(0.01 M, pH = 7.4). To avoid potential interference of PS-NPs, the algal cells were properly washed with phosphate buffer and then were homogenized by sonication in an ice bath for 5 min. The homogenate was centrifuged and the supernatant was collected for further analysis. The proteins were detected by Coomassie bright blue G-250 method [44 (link)]. ROS was measured by conversion of nonfluorescent 2′7′-dichlorofluorescin diacetate (DCFDA) to the higher fluorescent compound dichlorofluorescein (DCF) as described by Wang and Joseph [45 (link)]. Fluorescence intensities were measured by SpectraMax M5 Microplate Reader (Molecular Devices, USA) under the condition of 488 nm excitation and 530 nm emission wavelengths. Malondialdehyde (MDA), a molecular indicator of lipid peroxidation [22 (link)], was evaluated using a microscale MDA assay kit (Nanjing jiancheng Bioengineering Institute, Nanjing, China) according to the manufacturer’s protocol. Catalase (CAT) activity was also measured using a CAT assay kit (Nanjing jiancheng Bioengineering Institute, Nanjing, China). All biomarker concentrations were normalized to their protein content, respectively. Each experiment was conducted with three replicates.