Differential expression of secretory aspartyl proteinase genes (SAP1-10) in oral Candida albicans isolates with distinct karyotypes.
Two karyotypes of oral Candida albicans isolates, named b and c, constituted >80% of a collection from healthy carriers (22 b and 16 c isolates) and oral candidiasis patients who were either infected (31 b and 16 c isolates) or uninfected (13 b and 38 c isolates) with human immunodeficiency virus (HIV). The prevalence of the b and c karyotypes within HIV-positive and HIV-negative patients, respectively, who were suffering from oral candidiasis (P < or = 0.0001) suggested that these two types possessed different virulence potentials. Since C. albicans proteinases (Saps) are virulence factors in oral candidiasis, we evaluated whether the b and c karyotypes secreted different levels of Saps and expressed different patterns of Sap-encoding genes (SAP1-10). We found that the mean value of Sap activity was significantly lower (P = 0.003) in the commensal type than in the infectious b karyotype, whereas Sap activity in the commensal c type was as high as that registered for the infectious c strains. Marked differences in SAP mRNA expression were observed in commensal strains under non-Sap-inducing conditions, with all SAP genes being expressed only by strains with the c karyotype; interestingly, none of the commensal b strains expressed SAP2. In addition, while all of the SAP1-10 genes were detectable under Sap-inducing conditions, the timing of their expression during growth differed significantly, with mRNAs of SAP1-10 genes detected at 8 and 24 h postinoculation in c and b commensal strains, respectively. This provides the first evidence that commensal oral C. albicans isolates with distinct karyotypes are characterized by different patterns of SAP1-10 gene expression and different levels of Sap secretion.
Dipartimento di Patologia Sperimentale, Biotecnologie Mediche, Infettivologia ed Epidemiologia, Sezione di Microbiologia e Virologia, Università di Pisa, Pisa, Italy.
Arianna
A
Tavanti
Giacomo
G
Pardini
Daniele
D
Campa
Paola
P
Davini
Antonella
A
Lupetti
Sonia
S
Senesi
D017088:AIDS-Related Opportunistic Infections / Q000382:microbiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism*; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D002180:Candidiasis, Oral / Q000382:microbiology*; D002353:Carrier State / Q000382:microbiology*; D005260:Female; D015966:Gene Expression Regulation, Fungal; D015658:HIV Infections / Q000150:complications; D006801:Humans; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014774:Virulence
D012333:RNA, Messenger; D016282:Aspartic Acid Endopeptidases; C086390:SAP1 protein, Candida albicans