| Many putative virulence attributes are described in C. albicans , but the relevance of several to human infections is speculative. We investigated the significance of these to humans by attempting expression analysis of organisms from vaginal washings from patients with C. albicans vaginitis, using microarray and real time PCR. Microarray analysis of clinical samples was cut short by a lack of adequate RNA. Actin primed real time PCR analyses of the RNA suggested a poor yield. However, expression information from clinical RNAs was possible with real time PCR. Due to limited RNA, only 3 virulence genes (GCA, HWP and MNTI) gave analyzable data, interpretation of which was limited due to the absence of in-vitro controls. When related to actin expression, these genes were assessed to be expressed only in some clinical samples to moderate levels suggesting that they are either not essential or only essential at particular stages of infection.; We also examined C. albicans response, in-vitro , to factors prominent in in-vivo environments, cholesterol representing systemic infections and acetic acid representing vaginal infections, in terms of virulence expression and reaction to FLZ. Despite conditions permitting limited uptake, cholesterol enhanced FLZ mediated cell inhibition, but did not demonstrate influence on virulence or ERG gene expression. But, cholesterol and FLZ together repressed CDR1 expression, possibly explaining cholesterol enhancement of FLZ inhibitory activity. Acetate rendered FLZ fungicidal, best observed under conditions mimicking the vaginal microenvironment. Expression analysis suggested a stress susceptible phenotype, perturbation of membrane transporters and or enhanced inhibition of the sterol synthetic pathway as possible mechanism for the cidal phenomenon. Virulence gene expression changes were not appreciated when analyzing gene expression influences of acetate alone. |
