Candida albicans pathogenicity: A proteomic perspective

The limited number of treatments for oral candidiasis resulted in the emergence of azole-resistant Candida albicans strains, thus enforcing the need for novel antifungal treatments. Although histatin 5 (H5) demonstrates antifungal activity, its inhibitory effect when adhered to hydroxyapatite and Polymetylmethacrylate (PMMA) surfaces, resembling conditions of the in vivo pellicle, remains unexplored. The objective of this in vitro study was to determine whether surface-adhered H5 inhibits the colonization of C. albicans on hydroxyapatite and/or PMMA. The C. albicans assay involved developing a mono-protein pellicle (either H5 or albumin) on hydroxyapatite and PMMA discs, introducing C. albicans and counting the number of adhered cells, throughout time, using scanning electron microscopy. A negative binomial statistical model and the Tukey-Kramer test were used for statistical analysis, with p < 0.01 indicating significance. H5-coated PMMA had significantly reduced number of cells compared to albumin-coated PMMA at 30, 90 and 1440 min (p < 0.0001), with the number of cells decreasing significantly in 90 and 1440 min (p < 0.0001). Similarly, H5-coated hydroxyapatite had significantly fewer cells compared to the albumin-coated surface at 90 and 1440 min (p < 0.0001), with the number of cells decreasing significantly at 30, 90 and 1440 min (p < 0.0001). In conclusion, C. albicans colonization was most inhibited by PMMA and hydroxyapatite-adhered H5 after 1440 min, illustrating the time-dependent effect of H5. In addition, yeast cells colonized albumin-coated PMMA, while dense hyphal networks formed on albumincoated hydroxyapatite, suggesting that C. albicans morphology is influenced by the surface available for albumin adhesion.

Section: Introductionmentioning

confidence: 97%

The effect of histatin 5, adsorbed on PMMA and hydroxyapatite, on Candida albicans colonization

Vukosavljevic

Custódio

Cury

et al. 2012

“…Correct and accurate identification of the candidal species infecting an oral candidiasis patient is highly important, as different antifungal agents are effective against different candidal species (Ellepola et al , ). Furthermore, candidal infections are typically treated with azole antifungal drugs, mainly fluconazole; however, many infections are caused by non‐ albicans Candida (NAC) species that may have fluconazole resistance (Niimi et al , ). As the most conserved region in the fungal genome, the rDNA region is suitable for analysis of phylogenetic differences (Iwen et al , ), and thus is potentially useful for candidal species identification.…”

Section: Introductionmentioning

confidence: 99%

Distribution of Candida in the oral cavity and its differentiation based on the internally transcribed spacer (ITS) regions of rDNA

Zahir

Himratul-Aznita

2012

This study aimed to determine the distribution of Candida species in the oral cavity and differentiate the species based on PCR amplification, including HinfI and MspI digestion, in order to assess the effectiveness of using the rDNA region for species identification. Samples from saliva as well as palate, tongue and cheek mucosa surfaces were collected from 45 individuals, consisting of three groups: periodontal disease patients; denture-wearers; and the control group. The samples were serially diluted, spread on BHI and YPD agar plates and scored for colony-forming units (CFUs). Fifteen random candidal colonies were isolated and subjected to genomic DNA extraction, based on glass beads disruption. Four primers were used to amplify regions in the rDNA, and the ITSI-5.8S-ITSII PCR product was digested by HinfI and MspI restriction enzymes. The microbial loads on all sites of the denture-wearers were found to be significantly higher than control, while in the periodontal disease group only the microbial loads on the tongue were significantly higher than control. Meanwhile, there was no significant difference at other sites. The restriction fragment lengths of the clinical samples were compared to those of seven control species, allowing the differentiation of all seven species and the identification of 14 species from the clinical samples. The MspI restriction digest was not able to distinguish between C. albicans and C. dubliniensis, whereas the HinfI digest could not distinguish between C. tropicalis and C. parapsilosis. It was concluded that PCR-RFLP of the candidal rDNA region has potential for species identification. This study demonstrates the potential use of candidal rDNA as a means for identifying Candida species, based on genotype. The results also indicate the possibility of constructing genetic probes that target specific restriction fragments in the ITSI-5.8S-ITSII region, enabling swift and precise identification of Candida species.

“…However, genetic studies of C. albicans using S. cerevisiae homologues have some limitations. Approximately 5% of C. albicans genes analysed to date have no homology with S. cerevisiae (Niimi et al , 1999; Magee and Scherer, 1998). In addition, S. cerevisiae is essentially avirulent and does not produce a true hyphal morphology as does C. albicans (Niimi et al , 1999).…”

Section: Introductionmentioning

confidence: 99%

“…Two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE) is a useful tool for the analysis of complex mixtures of proteins. Many proteomic approaches using 2D‐PAGE have been undertaken to find proteins synthesized during C. albicans morphogenesis (Niimi et al , 1999; Pitarch et al , 1999). However, few proteins relevant to morphogenesis have been identified so far due to the limitations of 2D‐PAGE and insufficient protein data for C. albicans .…”

Section: Introductionmentioning

confidence: 99%

Identification of proteins highly expressed in the hyphae of Candida albicans by two‐dimensional electrophoresis

Yoo

Kim

Shin

et al. 2003

The increase in Candida albicans infections is caused by the increase in therapies resulting in immunocompromised patients. One factor required for C. albicans pathogenicity is the morphological transition from yeast to hypha. The protein profiles of whole extracts from yeasts and hyphae were examined using two-dimensional electrophoresis to identify the proteins related to the morphological transition. Over 900 protein spots were visualized by silver staining and 11 spots were increased more than three-fold reproducibly during hyphal differentiation. Six of the 11 spots were identified by peptide mass fingerprints, of which three represented PRA1, two PHR1 and the last TSA1. Vertical streak patterns of Pra1p and Phr1p indicated that posttranslational modifications seem to be caused by variable glycosylation. Comparative proteome analysis between the wild-type and the deletion mutants, CAMB43 ( pra1 ) and CAS10 ( phr1 ), further confirmed the identity of PRA1 and PHR1. Interestingly, Pra1p was downregulated in phr1-deleted mutants. Only PHR1 transcription was increased, indicating that PRA1 and TSA1 are controlled at the post-translational level.