Differential expression of CPH1 and EFG1 genes in planktonic and biofilm Candida albicans

Abstract

Objective To detect the expression of CPH1 and EFG1,the transcription factors,in planktonic stage and various phases during biofilm stage of Candida albicans,and to explore their roles in biofilm formation.Methods Confocal scanning laser microscope was employed for morphological examination of biofilm formation of ATCC90028,the strain for quality control,and the clinically isolated strain 14215 adhering to polyethylene film for 24 hours.The total RNA of 6 clinically isolated strains (13860,13874,14127,14371,14215 and 14533) and ATCC90028 during planktonic stage,and at early (4-hour adhesion to polyethylene film),intermediate ( 12-hour adhesion to polyethylene film) and late phase (24-hour adhesion to polyethylene film) during biofilm stage was extracted respectively.Expression of CPH1 and EFG1 genes was determined using fluorescent quantitative polymerase chain reaction.Results After the 24-hour adhesion to polyethylene films,the ATCC90028 strain appeared mostly as blastospores in a single layer while the clinically isolated strain 14215 was in the form of hypha producing a three-dimensional biofilm.Expression of CPH1 and EFG1 was down-regulated in the early,intermediate and late phases during biofilm formation,compared with planktonic stage of the ATCC90028 strain.CPH1 expression in the strain 14215 did not differ statistically between the planktonic stage and early,intermediate and late phases during biofilm formation (all P＞0.05).Contrarily,EFG1 expression was up-regulated at early and intermediate stages during biofilm formation as compared with that during planktonic stage [ (0.141 (0.029-0.212) and 0.252 (0.103-0.943) vs 0.077 (0.018-0.113),all P＜0.05].No significant change in EFG1 expression was detected at the late phase during biofilm formation [0.091 (0.024- 0.354),P＞0.05].Conclusion Transcription factor EFG1 may play a critical role in the regulation of biofilm formation in clinically isolated Candida albicans strains. Key words: Candida albicans; biofilms; CPH1; EFG1; Gene expression