Intracellular ATP was estimated as described (33 (link)). Briefly, 150 μl of cell cultures were aliquoted into PCR tubes, immediately heated at 80° C for 10 min, and subsequently placed on ice. At the same time, 1 ml of each of these cultures was transferred to a 1.5 ml tube and placed on ice. Using a multichannel pipette, 30–50 μl of heat-inactivated (80° C for 10 min) cells were transferred to 96-well black plates (Corning) containing 150 μl of BacTiter-Glo Microbial Cell Viability Assay Solution (Promega). Samples were mixed by pipetting, and their luminescence was measured in a Synergy H1 Reader (BioTek). Cells from the 1 ml of culture aliquots were collected by centrifugation (4° C at 14,000 rpm for 5 min), resuspended in 250 μl of 0.5% SDS, and lysed by boiling at 100° C for 10 min. The concentrations of proteins in the cell lysates were estimated using a Pierce BCA Protein Assay Kit (Thermo Fisher Scientific). Protein concentrations in these samples were used to calculate the protein amount present in the luminescence reactions. ATP levels were calculated by normalizing luminescence values of each sample by their protein content.