| Autor: |
Ortiz BJ; Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States., Boursier ME; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Barrett KL; Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States., Manson DE; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Amador-Noguez D; Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States., Abbott NL; Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States., Blackwell HE; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Lynn DM; Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States.; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States. |
| Abstrakt: |
We report aqueous emulsions of thermotropic liquid crystals (LCs) that can intercept and report on the presence of N -acyl-l-homoserine lactones (AHLs), a class of amphiphiles used by pathogenic bacteria to regulate quorum sensing (QS), monitor population densities, and initiate group activities, including biofilm formation and virulence factor production. The concentration of AHL required to promote "bipolar" to "radial" transitions in micrometer-scale droplets of the nematic LC 4'-pentyl-cyanobiphenyl (5CB) decreases with increasing carbon number in the acyl tail, reaching a threshold concentration of 7.1 μM for 3-oxo-C12-AHL, a native QS signal in the pathogen Pseudomonas aeruginosa . The LC droplets in these emulsions also respond to biologically relevant concentrations of the biosurfactant rhamnolipid, a virulence factor produced by communities of P. aeruginosa under the control of QS. Systematic studies using bacterial mutants support the conclusion that these emulsions respond selectively to the production of rhamnolipid and AHLs and not to other products produced by bacteria at lower (subquorate) population densities. Finally, these emulsions remain configurationally stable in growth media, enabling them to be deployed either in bacterial supernatants or in situ in bacterial cultures to eavesdrop on QS and report on changes in bacterial group behavior that can be detected in real time using polarized light. Our results provide new tools to detect and report on bacterial QS and virulence and a materials platform for the rapid and in situ monitoring of bacterial communication and resulting group behaviors in bacterial communities. |
