Biomate 3

H₂O₂ in fresh leaves was analyzed using the method reported by Hu et al. (2012) (link). The absorbance was recorded at 390 nm with the spectrophotometer (Biomate 3S, Thermo). Malondialdehyde (MDA) content was quantified using the method reported by Heath and Packer (1968) (link), which is related with the level of lipid peroxidation in the leaves. The absorbance was read at 532 and 600 nm by the spectrophotometer (Biomate 3S, Thermo) with thiobarbituric acid (1%) in 20% trichloroacetic acid as control. The Proline content in leaves was quantified using the method by Bates et al. (1973) (link). The absorbance was measured spectrophotometrically (Biomate 3S, Thermo) at 520 nm and toluene was used as blank.

The isolation of total RNA from RLS₄₀ was carried out using a TRIzol reagent (Sigma-Aldrich, Darmstadt, Germany) according to the manufacturer’s protocol. Tumour pieces from the mice of the control and experimental groups were homogenised. Blood serum was prepared from the whole blood of mice via clot formation at 37 °C for 30 min and at 4 °C overnight, followed by clot discarding and centrifugation (4000 rpm, 4 °C, 20 min). Serum samples were pooled according to groups. Total RNA was extracted from the serum samples, RLS₄₀ cells and homogenates of the tumour tissue immediately using a TRIzol reagent (Sigma-Aldrich, Darmstadt, Germany) according to the manufacturer’s protocol.
RNA concentration was measured via absorbance at 260 and 280 nm using a Bio Mate 3 (Thermo Electron Corporation, Waltham, MA, USA) spectrophotometer and Qubit (Invitrogen, Carlsbad, CA, USA). The total RNA integrity and quantity were checked using Agilent 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA).

The frozen bacterial isolates (− 80 °C in glycerol) were revived by inoculating Brain Heart Infusion (BHI) agar medium and incubated at 37 °C overnight. Three to four colonies from each of the overnight cultures were suspended in separate tubes containing 1 mL of 1X Phosphate Buffered Saline (PBS) (VWR life sciences), and bacterial suspension’s absorbance at 600 nm (A600) was measured spectrophotometrically (Thermo Electron Corporation, BioMate 3, USA) (Supplementary Table S5). To determine the number of viable cells, each bacterial suspension was further serial diluted (up to 10^–6 in PBS), and 50 µL aliquots were plated on BHI agar plates to determine colony-forming units per mL (CFU/mL). Multiple bacterial suspensions were prepared to investigate the correlation between A600 and CFU/mL for each bacterial strain used in the study (Supplementary Table S5). To mimic the clinical sepsis levels, the number of viable cells in the blood-spiking bacterial inoculum was set to < 50 CFU/mL. A600 values were only used to estimate the number of cells/mL in the inoculum, and exact CFU counts were performed using plate counting as described previously (Supplementary Fig. S6).