title: The effect of tea tree oil and antifungal agents on a reporter for yeast cell integrity signalling.
abstract: Cell integrity in Saccharomyces cerevisiae is ensured by a rigid cell wall whose synthesis is controlled by a highly conserved MAP kinase signal transduction cascade. Stress at the cell surface is detected by a set of sensors and ultimately transmitted through this cascade to the transcription factor Rlm1, which governs expression of many genes encoding enzymes of cell wall biosynthesis. We here report on a number of versatile reporter constructs which link activation of a hybrid, Rlm1-lexA, by the MAP kinase Mpk1/Slt2 to the expression of the bacterial lacZ gene. This system was adapted to automated microwell screening and shown to be activated by a number of compounds inhibiting cell wall biosynthesis or interfering with plasma membrane function. In addition, we tested tea tree oil and two of its purified constituents (alpha-terpineol, terpinen-4-ol) for their effects on growth and on cell integrity signalling using such reporter strains. Tea tree oil was found to inhibit growth of wild-type and slg1/wsc1 mutant cells at a threshold of approximately 0.1% v/v, with the purified compounds acting already at half these concentrations. A mid2 deletion displayed hyper-resistance. Tea tree oil also induces the signalling pathway in a dose-dependent manner.
authors.affiliation: Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, Barbarastrasse 11, D-49076 Osnabrück, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Straede
authors.forename: Andy
authors.initials: A
authors.lastname: Corran
authors.forename: James
authors.initials: J
authors.lastname: Bundy
authors.forename: Jürgen J
authors.initials: JJ
authors.lastname: Heinisch
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002473:Cell Wall / Q000378:metabolism* / Q000502:physiology; D017930:Genes, Reporter / Q000187:drug effects* / Q000502:physiology; D026161:MADS Domain Proteins; D020935:MAP Kinase Signaling System; D008826:Microbial Sensitivity Tests; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020947:Tea Tree Oil / Q000737:chemistry / Q000494:pharmacology*; D013729:Terpenes / Q000737:chemistry / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D026161:MADS Domain Proteins; C095725:RLM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013729:Terpenes; D014157:Transcription Factors; C034019:terpinenol-4; D020947:Tea Tree Oil