title: Phospholipase B enzyme expression is not associated with other virulence attributes in Candida albicans isolates from patients with human immunodeficiency virus infection.
abstract: The extracellular phospholipases of Candida albicans are considered to play a significant role in the pathogenesis of human infections. Therefore 30 clinical isolates of C. albicans from human immunodeficiency virus (HIV)-infected individuals were screened for phospholipase production in vitro (using an egg-yolk-agar medium). Two groups of six isolates with positive (group A) or deficient (group B) phospholipase activity were then analysed for phospholipase B1 (PLB1) gene expression both in egg-yolk-agar and yeast extract/peptone/dextrose (YPD) broth media. A total of four virulence attributes of these two groups were in turn characterized, namely their germ-tube formation, cell-surface-hydrophobicity (CSH), adhesion to buccal epithelial cells (ABEC) and haemolysin production, and these factors were subsequently correlated with PLB1 expression. In the phospholipase-producing isolates (group A) a positive correlation was demonstrated between phospholipase production and the degree of PLB1 expression in YPD medium (r = 0.96, P < 0.01). No such association was observed in group A isolates for PLB1 expression in egg-yolk-agar medium. Further, PLB1 expression in egg-yolk agar was less than that in YPD medium, although a positive correlation was seen between the expression levels on regression analysis (r = 0.86, P = 0.026). Surprisingly, however, no significant associations were observed in either growth media between PLB1 expression and any of the four pathogenic attributes examined (P < 0.001). A significant correlation was seen between CSH and ABEC (r = 0.74) in group A isolates. The phospholipase-deficient group B, however, demonstrated a significant correlation between the latter parameters (r = +0.50) and also between germ-tube formation and ABEC (r = -0.59), and germ-tube formation and haemolysin production (r = +0.31). It appears that in oral C. albicans isolates in HIV infection there may be no significant association between the degree of PLB1 expression and other widely recognized major virulence attributes.
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: Y H
authors.initials: YH
authors.lastname: Samaranayake
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: R S
authors.initials: RS
authors.lastname: Dassanayake
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: J Ams
authors.initials: JA
authors.lastname: Jayatilake
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: B Pk
authors.initials: BP
authors.lastname: Cheung
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: J Yy
authors.initials: JY
authors.lastname: Yau
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: K Ws
authors.initials: KW
authors.lastname: Yeung
authors.affiliation: Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong 2Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka 3Department of Microbiology, Faculty of Dentistry University of Peradeniya, Sri Lanka.
authors.forename: L P
authors.initials: LP
authors.lastname: Samaranayake
mesh_terms: D001422:Bacterial Adhesion; D002176:Candida albicans / Q000378:metabolism* / Q000472:pathogenicity; D002177:Candidiasis / Q000150:complications*; D003470:Culture Media; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology; D005656:Fungal Proteins / Q000378:metabolism*; D015658:HIV Infections / Q000150:complications*; D006460:Hemolysin Proteins / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008245:Lysophospholipase / Q000378:metabolism*; D009055:Mouth / Q000378:metabolism / Q000382:microbiology; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D006460:Hemolysin Proteins; C490271:PLB1 protein, Candida albicans; D037521:Virulence Factors; D008245:Lysophospholipase