title: The quorum-sensing molecule E,E-farnesol--its variable secretion and its impact on the growth and metabolism of Candida species.
abstract: Diseases caused by Candida species are an increasing problem. Candida species are associated with high overall mortality, due to a variety of virulence factors such as the yeast-to-hyphal switch and proteolytic enzymes. The phenomenon of microbial communication known as quorum sensing also seems to play an important role. The main characteristics of the quorum-sensing molecule E,E-farnesol are well known for C. albicans. The present study focused on two questions. One of them concerned the secretion of E,E-farnesol by C. albicans and involved a close examination of the effect of the medium (serum) and the origin of the isolates used. The second one dealt with the activity of E,E-farnesol in non-C. albicans species, such as C. tropicalis and C. parapsilosis, e.g. its impact on biofilm formation and growth. Under serum conditions, C. albicans produced up to 58% more E,E-farnesol at 37 degrees C than at 30 degrees C. The growth of all isolates was reduced and delayed by the administration of E,E-farnesol. Of all Candida species, C. tropicalis isolates were most strongly affected by the addition of E,E-farnesol. Biofilm formation on polystyrene was affected by E,E-farnesol treatment in all non-C. albicans species and C. albicans. E,E-farnesol exerts its main effect by altering the metabolic activity and growth inhibition of treated Candida species. The results obtained indicate that the presence of E,E-farnesol in the environment not only regulates the morphology of the Candida species but also affects its fitness. In this regard, the secretion of E,E-farnesol might provide an advantage for members of the microbial community.
authors.affiliation: Charité-Universitätsmedizin Berlin, Medical Department, Division of Oncology and Haematology, CCM, Berlin, Germany. kai.weber@charite.de
authors.forename: K
authors.initials: K
authors.lastname: Weber
authors.forename: B
authors.initials: B
authors.lastname: Schulz
authors.forename: M
authors.initials: M
authors.lastname: Ruhnke
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D002175:Candida / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D002177:Candidiasis / Q000382:microbiology; D003470:Culture Media / Q000737:chemistry; D005204:Farnesol / Q000378:metabolism*; D006801:Humans; D053038:Quorum Sensing; D044967:Serum / Q000382:microbiology; D013696:Temperature
chemical_list: D003470:Culture Media; D005204:Farnesol