García-Sánchez Susana, Aubert Sylvie, Iraqui Ismaïl, Janbon Guilhem, Ghigo Jean-Marc, d'Enfert Christophe
Biologie et Pathogénicité Fongiques, Institut Pasteur, 75015 Paris, France.
Eukaryot Cell. 2004 Apr;3(2):536-45. doi: 10.1128/EC.3.2.536-545.2004.
Like many bacteria, yeast species can form biofilms on several surfaces. Candida albicans colonizes the surfaces of catheters, prostheses, and epithelia, forming biofilms that are extremely resistant to antifungal drugs. We have used transcript profiling to investigate the specific properties of C. albicans biofilms. Biofilm and planktonic cultures produced under different conditions of nutrient flow, aerobiosis, or glucose concentration were compared by overall gene expression correlation. Correlation was much higher between biofilms than planktonic populations irrespective of the growth conditions, indicating that biofilm populations formed in different environments display very similar and specific transcript profiles. A first cluster of 325 differentially expressed genes was identified. In agreement with the overrepresentation of amino acid biosynthesis genes in this cluster, Gcn4p, a regulator of amino acid metabolism, was shown to be required for normal biofilm growth. To identify biofilm-related genes that are independent of mycelial development, we studied the transcriptome of biofilms produced by a wild-type, hypha-producing strain and a cph1/cph1 efg1/efg1 strain defective for hypha production. This analysis identified a cluster of 317 genes expressed independently of hypha formation, whereas 86 genes were dependent on mycelial development. Both sets revealed the activation of the sulfur-amino acid biosynthesis pathway as a feature of C. albicans biofilms.
与许多细菌一样，酵母菌种也能在多种表面形成生物膜。白色念珠菌可在导管、假体和上皮表面定殖，形成对抗真菌药物极具抗性的生物膜。我们利用转录谱分析来研究白色念珠菌生物膜的特定特性。通过整体基因表达相关性比较了在不同营养流、需氧状态或葡萄糖浓度条件下产生的生物膜和浮游培养物。无论生长条件如何，生物膜之间的相关性都远高于浮游群体，这表明在不同环境中形成的生物膜群体表现出非常相似且特定的转录谱。鉴定出了一组325个差异表达基因。与该簇中氨基酸生物合成基因的过度表达一致，氨基酸代谢调节因子Gcn4p被证明是生物膜正常生长所必需的。为了鉴定与菌丝体发育无关的生物膜相关基因，我们研究了野生型产菌丝菌株和产菌丝缺陷的cph1/cph1 efg1/efg1菌株产生的生物膜的转录组。该分析鉴定出一组317个独立于菌丝体形成表达的基因，而86个基因依赖于菌丝体发育。两组结果均显示硫氨基酸生物合成途径的激活是白色念珠菌生物膜的一个特征。
