Analyzing Chemical Compound Modulators of the Vibrio Cholerae PTS and Biofilm Formation

Phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) is a multistep chemical process which regulates the intake and use of carbohydrates by bacteria. It is used for the transfer of sugars in Vibrio cholerae and requires phosphate transfer. In the absence of transported sugars, phosphate will accumulate on the protein components of the system and will indirectly analyze the PTS sugars present and metabolic state of the bacteria cell, allowing the bacteria to form biofilms. Biofilms are multi-layered communities of bacterial cells that grow attached to one another. In addition to controlling sugar uptake by bacteria, the PTS regulates several cellular functions such as chemotaxis, glycogen metabolism, catabolite repression and the aforementioned biofilm formation.

In this study, V. cholerae MO10 served as the model organism. It was grown in the absence of chemical compounds as a negative control, while an altered strain lacking PTS activity served as a positive control. A chemical screen was used to identify chemical compounds that promote the production of Vibrio cholerae biofilms. Growth kinetics was evaluated in absorbance-based microplate assays, and quantitative biofilm assays were performed in borosilicate glass tubes. All assays were monitored by spectrophotometry.

Biofilm induction was confirmed by monitoring the growth of Vibrio cholerae in the presence or absence of chemical compounds. Significant biofilm growth was seen in LB with three specific compounds, and one of the three compounds was further analyzed in Minimal Media Pyruvate. Biofilm growth was seen to be concentration dependent.

Further assays are underway to see the effect of this candidate compound on Staphylococcus aureus biofilms. Growth kinetics and quantitative biofilm assays are being performed in absorbance based microplate assays, and monitored by spectrophotometry.

These assays will determine whether or not biofilm induction occurs through interactions with the bacterial PTS. By modulating the PTS, chemical compounds that regulate biofilm formation in gram negative and gram positive bacterium will be identified and characterized. This may lead to the development of new microbial control strategies with applications in biological, medical, and pharmaceutical sciences.

Funder Acknowledgement(s): This study was supported by a grant from NSF (Research Initiation Award #1505301) awarded to Patrick Ymele-Leki PhD, Assistant Professor of Chemical Engineering, Howard University, Washington, DC 20059.