Present address: Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, NH 03755, USA.
A Pseudomonas aeruginosa quorum-sensing molecule influences Candida albicans morphology
Article first published online: 15 OCT 2004
Volume 54, Issue 5, pages 1212–1223, December 2004
How to Cite
Hogan, D. A., Vik, Å. and Kolter, R. (2004), A Pseudomonas aeruginosa quorum-sensing molecule influences Candida albicans morphology. Molecular Microbiology, 54: 1212–1223. doi: 10.1111/j.1365-2958.2004.04349.x
- Issue published online: 15 OCT 2004
- Article first published online: 15 OCT 2004
- Accepted 11 August, 2004.
Candida albicans is an opportunistic pathogen that is commonly found as a member of the human microflora. The ability of C. albicans to alter its cellular morphology has been associated with its virulence; yeast cells are more prevalent in commensal interactions whereas filamentous cells appear important in opportunistic infections. C. albicans encounters a multitude of other microbial species in the host environment and it is likely that they impact the C. albicans transition between virulent and non-virulent states. Here, we report that C. albicans morphology is significantly affected by the presence of Pseudomonas aeruginosa, another opportunistic pathogen. In a screen using a C. albicans HWP1–lacZ strain to indicate regions of filamentous growth, we identified P. aeruginosa mutants incapable of inhibiting C. albicans filamentation. Through these studies, we found that 3-oxo-C12 homoserine lactone, a cell–cell signalling molecule produced by P. aeruginosa, was sufficient to inhibit C. albicans filamentation without affecting fungal growth rates. Both microscopic analysis and real-time reverse transcription polymerase chain reaction analysis of morphology-specific markers confirmed that filamentation was suppressed by 200 µM 3-oxo-C12 homoserine lactone. Structurally related compounds with a 12-carbon chain length, e.g. C12-acyl homoserine lactone and dodecanol also affected C. albicans filamentation at similar concentrations. In contrast, other acylated homoserine lactones of different chain lengths did not affect fungal morphology. The activity of 3OC12HSL is compared with that of farnesol, a C. albicans-produced molecule also with a C12-backbone. The effects that bacteria have on the morphology of C. albicans represents one of the ways by which bacteria can influence the behaviour of fungal cells.