Journal of Basic Microbiology 2009, 49, 579 – 583 579 © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jbm-journal.com Short Communication 2-dodecanol (decyl methyl carbinol) inhibits hyphal formation and SIR2 expression in C. albicans Crystale Siew-Ying Lim 1 , Won-Fen Wong 1, 5 , Rozita Rosli 2 , Kee-Peng Ng 3 , Heng-Fong Seow 4, 6 and Pei-Pei Chong 1 1 Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, University Putra Malaysia, Serdang, Selangor, Malaysia 2 Department of Obstetrics and Gynaecology, Faculty of Medicine & Health Sciences, University Putra Malaysia, Serdang, Selangor, Malaysia 3 Department of Microbiology, Faculty of Medicine, University Malaya, Selangor, Malaysia 4 Department of Pathology, Faculty of Medicine & Health Sciences, University Putra Malaysia, Serdang, Selangor, Malaysia 5 Department of Molecular Immunology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan 6 School of Biomedical & Health Sciences, Victoria University, St. Albans Campus, Melbourne, Australia Candida albicans is capable of undergoing yeast-hypha transition to attain pathogenicity in humans. In this study, we investigated the differential expression of CaSIR2 via quantitative real-time PCR (qPCR), during yeast-hypha transition with and without the presence of 2-do- decanol. SIR2 transcript levels were found to be significantly enhanced after hyphal induction as compared to the yeast form. This study found that 2-dodecanol is able to inhibit hyphal development and block SIR2 up-regulation, even in hyphal-inducing growth conditions. We suggest that SIR2 may be involved in Candida albicans quorum-sensing and serum-induced yeast- hyphae transition via the Ras1-cAMP-Efg1 signalling cascade. Supporting Information for this article is available from the author or on the WWW under http://www.wileyvch.de/contents/jc_2248/2009/200900035_s.pdf Keywords: Candida albicans / SIR2 gene / Quantitative real-time PCR / Gene expression / Dodecanol Received: February 04, 2009; accepted: May 21, 2009 DOI 10.1002/jobm.200900035 Introduction * Filamentation is widely believed to be necessary for C. albicans pathogenicity [1, 2]. Therefore the inhibition of filamentation may reduce the pathogenesis of sys- temic candidiasis. CaSIR2 appears to play a role in phe- notypic switching [3], and its expression was recently shown to be suppressed by fresh garlic treatment [4]. Dodecanol has been shown by Hogan et al. [5] to be simi- lar to farnesol, a C. albicans quorum-sensing molecule (QSMs), in its ability to inhibit yeast-hyphae transition. Correspondence: Pei-Pei Chong, Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, University Putra Malaysia, Serdang, Selangor, Malaysia E-mail: cpp@medic.upm.edu.my Phone: +603 8947 2302 Fax: +603 8943 6178 They also hypothesize that 12-carbon molecules are able to act as QSMs and inhibit hyphae production. In this study we describe the expression profiles of SIR2 mRNA in C. albicans during various yeast-hypha transition time-points with and without the presence of 2-dodecanol (also a 12-carbon molecule) through rela- tive quantitative real-time PCR. We hypothesize that 2-dodecanol has an effect on SIR2 expression, and that any differential expression of this gene in C. albicans would imply its involvement in quorum-sensing and hyphae development. Materials and methods Candida albicans ATCC 14053 pure yeast form cells were grown as previously described [6] with modifications, in