The Studies On The Influencing Factors Of Dimorphism Of Candida Albicans

Objective:To research some interfering factors act on dimorphism of Candida albicans. To find key genes which control hyphal formation of Candida albicans.Methods:1,Eight strains of Candida albicans culturing from different resoures (a standard strain and strains from clinical specimens) were tested. Interfering factors, such as spores concentration, cultural temperature, media components and pH were acted on the Candida albicans. The changes of hyphal formation ratio and growth features of Candida albicans were observed.2,Three breaking fungi cell wall methods were used in the experiments: Grinded Candida albicans in -80℃or in liquid nitrogen, and acid washed glass beads. Total RNA of hyphae and yeasts were extracted by RTIzol agent, and then analyzed the quality and integrity of extracted RNA.3,Analyzed mRNA different expressions of four genes(EFG1, HWP1, HYR1 and HGC1) which related to dimophism of Candida albicans by semiquantitative reverse transcriptase polymerase reaction with an intrinsic control.4,Exposed eight strains of Candida albicans to NB-UVB in clinical dosages three times daily for 7 days. Morphological changes and hyphal formation of the fungi were observed.Results:1,Hyphae became floccus in liquid media. Conidiosporespores failed easily at pH 5.0. Big conidiospore formed at pH9.0.Neutral pH is best for hyphaeformation. Hyphae developed well in RPMI1640 medium with 10 percents of fetal bovine serum, pH at 7.0, spore concentration was 5×10~6/ml, incubated at 38℃for four to eight hours. 2,Total RNA concentrations ((?)±s, ug/ul) were extracted with different methods were 0.464±0.101 ( grinded in -80℃), 0.911±0.413( acid washed glass beads ) and 1.418±0.524(grinded in liquid nitrogen ).The integrity of RNA with last two methods are better than the first one.3,HWP1 and HGC1 were expressed in hypha and negative in yeast of Candida albicans. EFG1 and HYR1 were expressed in both forms.4,Hyphae of candia albicans were reduced and blastspores were increased which paralleled with UVB irradiation dosage. Hyphae developing were inhibited obviously when irradiation dose was over 1.5 J/cm~2.Conclusions:1,Serum, neutral pH, adequate temparature are profitable to hyphal formation.2,Grinded candia albicans in liquid nitrogen and shocked candia albicans with acid washed glass beads are good broken-wall methods for RNA extration in Candida albicans. Among these three methods, Grinded in liquid nitrogen is the best.3,Hyphae are inhibited when the doses of UVB irradiation is between 0.4 J/cm~2 and 3.0J/cm~2.4,HWP1 and HGC1 are specific genes which control hyphal formation.