Monitoring ALS1 and ALS3 Gene Expression During In Vitro Candida albicans Biofilm Formation Under Continuous Flow Conditions
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ALS1 and ALS3 encode cell-surface associated glycoproteins that are considered to be important for Candida albicans biofilm formation. The main goal of the present study was to monitor ALS1 and ALS3 gene expression during C. albicans biofilm formation (on silicone) under continuous flow conditions, using the Centers for Disease Control biofilm reactor (CDC reactor). For ALS1, we found few changes in gene expression until later stages of biofilm formation (72 and 96 h) when this gene appeared to be downregulated relative to the gene expression level in the start culture. We observed an induction of ALS3 gene expression in the initial stages of biofilm formation (0.5, 1, and 6 h), whereas at later stages, this gene was also downregulated relative to the gene expression level in the start culture. We also found that biofilms of an als3/als3 deletion mutant contained less filaments at several time points (1, 6, 24, and 48 h), although filamentation as such was not affected in this strain. Together, our data indicate an important role for ALS3 in the early phases of biofilm formation in the CDC reactor, probably related to adhesion of filaments, while the role of ALS1 is less clear.
KeywordsCandida albicans Biofilms ALS1 ALS3 Gene expression Filamentation
We wish to thank Aaron Mitchell and Alistair Brown for providing strains and acknowledge Andrea Cochis, Hanne Thuysbaert, Sofie Vandevivere and Kim De Rijck for excellent technical assistance and Jo Vandesompele for useful advice concerning qPCR data analysis. KT and TC acknowledge the support of the Fonds voor Wetenschappelijk Onderzoek (FWO). This work was partially funded by the Belgian Federation against Cancer.
- 13.Hoyer LL, Green CB, Oh SH, Zhao X. Discovering the secrets of the Candida albicans agglutinin-like sequence (ALS) gene family—a sticky pursuit. Med Mycol. 2007;20:1–15.Google Scholar
- 18.Green CB, Zhao X, Yeater KM, Hoyer LL. Construction and real-time RT-PCR validation of Candida albicans PALS-GFP reporter strains and their use in flow cytometry analysis of ALS gene expression in budding and filamenting cells. Microbiology. 2005;151:1051–60. doi: 10.1099/mic.0.27696-0.PubMedCrossRefGoogle Scholar
- 25.Vandesompele J, De Preter K, Pattyn F, Poppe B, Van Roy N, De Paepe A, Speleman F. Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol. 2002;3:RESEARCH0034.Google Scholar
- 32.Coleman DA, Oh S, Zhao X, Hoyer LL. Dynamics of Als protein localization on the Candida albicans cell surface. In: Poster presentation on the 9th ASM conference on Candida and Candidiasis, Jersey City, New Jersey; 2008.Google Scholar