Department of Microbiology, University College Cork, Cork, Ireland.
Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK.
Microbiology (Reading). 2010 May;156(Pt 5):1476-1486. doi: 10.1099/mic.0.037549-0. Epub 2010 Feb 11.
Signal-mediated interactions between the human opportunistic pathogens Pseudomonas aeruginosa and Candida albicans affect virulence traits in both organisms. Phenotypic studies revealed that bacterial supernatant from four P. aeruginosa strains strongly reduced the ability of C. albicans to form biofilms on silicone. This was largely a consequence of inhibition of biofilm maturation, a phenomenon also observed with supernatant prepared from non-clinical bacterial species. The effects of supernatant on biofilm formation were not mediated via interference with the yeast-hyphal morphological switch and occurred regardless of the level of homoserine lactone (HSL) produced, indicating that the effect is HSL-independent. A transcriptome analysis to dissect the effects of the P. aeruginosa supernatants on gene expression in the early stages of C. albicans biofilm formation identified 238 genes that exhibited reproducible changes in expression in response to all four supernatants. In particular, there was a strong increase in the expression of genes related to drug or toxin efflux and a decrease in expression of genes associated with adhesion and biofilm formation. Furthermore, expression of YWP1, which encodes a protein known to inhibit biofilm formation, was significantly increased. Biofilm formation is a key aspect of C. albicans infections, therefore the capacity of P. aeruginosa to antagonize this has clear biomedical implications.
人类机会性病原体铜绿假单胞菌和白色念珠菌之间的信号介导相互作用影响这两种生物体的毒力特征。表型研究表明，来自四个铜绿假单胞菌菌株的细菌上清液强烈降低了白色念珠菌在硅酮上形成生物膜的能力。这主要是由于生物膜成熟的抑制，这一现象也在非临床细菌物种制备的上清液中观察到。上清液对生物膜形成的影响不是通过干扰酵母-菌丝形态转换来介导的，并且无论产生的高丝氨酸内酯 (HSL) 水平如何，都发生这种情况，表明该效应与 HSL 无关。为了剖析铜绿假单胞菌上清液对白色念珠菌生物膜形成早期基因表达的影响，进行了转录组分析，鉴定出 238 个基因，这些基因的表达在响应所有四种上清液时表现出可重复的变化。特别是，与药物或毒素外排相关的基因的表达强烈增加，而与粘附和生物膜形成相关的基因的表达减少。此外，编码已知抑制生物膜形成的蛋白质的 YWP1 基因的表达显著增加。生物膜形成是白色念珠菌感染的一个关键方面，因此铜绿假单胞菌拮抗这种能力具有明确的生物医学意义。
