Polyphosphate:Potential Modulator Of Survival In Lactobacillus Acidophilus

This study aims to quantify the polyphosphate levels in Lactobacillus acidophilus and investigate its impact on the physiological functions, thereby identifying new targets for controlling cariogenic bacteria. Confocal laser scanning microscopy(CLSM)was used to observe polyphosphates of Lactobacillus acidophilus. This polymer was extracted and purified by the chloroform/phenol method. Plate counting was performed to measure colony-forming units under various conditions (normal conditions, 0.0005% H2O2, pH=4 and polyphosphate kinase inhibitor). Crystal Violet staining was used to quantify bacterial biofilm formation. live-dead cell staining was employed to assessed bacterial viability. We developed a method to extract and purify polyphosphate from Lactobacillus acidophilus and the presence of this polymer was confirmed through CLSM and energy-dispersive X-ray spectroscopy (EDS) . Our findings indicated that 1 mg/L of polyphosphates could promote the growth of Lactobacillus acidophilus and enhance its stress resistance ( 0.0005% H2O2, pH=4) and biofilm formation increased by 1.3-fold compared to the control group, while high concentrations of polyphosphate exhibited antibacterial effects, reducing bacterial viability when adding 100 mg/L of exogenous polyphosphate. In this study, a potential polyphosphate inhibitor, gallein, was identified to significantly inhibit polyphosphate aggregation and exhibit growth-suppressive effects at a concentration of 50 μM. We successfully observed and extracted polyphosphate of Lactobacillus acidophilus using CLSM and chloroform/phenol method, which is critical for survival under extreme and general environmental conditions, including biofilm-forming. These results highlight the potential complexity of polyphosphate metabolism and function in Lactobacillus acidophilus.