Contact sensing in<i>Candida albicans</i>: a possible aid to epithelial penetration

Sherwood, J.; Gow, Neil A. R.; Gooday, Graham W.; Gregory, D. W.; Marshall, D.

doi:10.1080/02681219280000621

Cited by 110 publications

(85 citation statements)

References 19 publications

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“…Although hyphal formation is not a prerequisite for pathogenicity of C. albicans, biopsies of candidal infections often reveal hyphal adherence to and penetration through epithelial tissues, indicating increased pathogenicity in comparison with ovoid yeast forms (Sweet, 1997). It seems that the hyphal penetration into tissues is enhanced by thigmotropism, i.e., contact sensing by hyphae to find intracellular junctions or microscopic breaks on mucosal surfaces (Sherwood et al, 1992;Gow et al, 1994;Sweet, 1997). One of the key virulence determinants of Candida species is their ability to produce and secrete aspartyl proteases which digest a variety of host proteins.…”

Section: Virulence Factors Of Candidamentioning

confidence: 99%

Yeasts in Apical Periodontitis

Waltimo

Şen

Meurman

et al. 2003

Critical Reviews in Oral Biology & Medicine

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Microbiological reports of apical periodontitis have revealed that yeasts can be isolated from approximately 5-20% of infected root canals. They occur either in pure cultures or together with bacteria. Almost all isolated yeasts belong to the genus Candida, and the predominant species is C. albicans. Pheno- and genotypic profiles of C. albicans isolates show heterogeneity comparable with those of isolates from other oral sites. C. albicans expresses several virulence factors that are capable of infecting the dentin-pulp complex, including dentinal tubules. This causes, consequentially, an inflammatory response around the root apex, which suggests a pathogenic role for this organism in apical periodontitis. Yeasts are particularly associated with persistent root canal infections that do not respond favorably to conservative root canal therapy. This may be due to the resistance of all oral Candida species against a commonly used topical medicament, calcium hydroxide. However, other antimicrobial agents may offer alternative therapeutic approaches and improve the treatment of these persistent cases of apical periodontitis.

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Section: Virulence Factors Of Candidamentioning

confidence: 99%

Yeasts in Apical Periodontitis

Waltimo

Şen

Meurman

et al. 2003

Critical Reviews in Oral Biology & Medicine

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“…Candida cells have an array of mechanisms (virulence factors) which enable them to colonize new environments, a process often involving tissue penetration. Polarized hyphal growth facilitates directional growth toward a different environment, and thigmotropism or contact sensing (Sherwood et al, 1992) could allow the hyphae to invade tissues. C. albicans cells also secrete a number of hydrolytic enzymes which may play a role in tissue destruction and penetration.…”

Section: Removalmentioning

confidence: 99%

Oral Colonization By Candida Albicans

Cannon

Chaffin

1999

Critical Reviews in Oral Biology & Medicine

276

193

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Candida albicans is a commensal yeast normally present in small numbers in the oral flora of a large proportion of humans. Colonization of the oral cavity by C. albicans involves the acquisition and maintenance of a stable yeast population. Micro-organisms are continually being removed from the oral cavity by host clearance mechanisms, and so, in order to survive and inhabit this eco-system, C. albicans cells have to adhere and replicate. The oral cavity presents many niches for C. albicans colonization, and the yeast is able to adhere to a plethora of ligands. These include epithelial and bacterial cell-surface molecules, extracellular matrix proteins, and dental acrylic. In addition, saliva molecules, including basic proline-rich proteins, adsorbed to many oral surfaces promote C. albicans adherence. Several adhesins present in the C. albicans cell wall have now been partially characterized. Adherence involves lectin, protein-protein, and hydrophobic interactions. As C. albicans cells evade host defenses and colonize new environments by penetrating tissues, they are exposed to new adherence receptors and respond by expressing alternative adhesins. The relatively small number of commensal Candida cells in the oral flora raises the possibility that strategies can be devised to prevent oral colonization and infection. However, the variety of oral niches and the complex adherence mechanisms of the yeast mean that such a goal will remain elusive until more is known about the contribution of each mechanism to colonization.

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“…albicans are dimorphic fungi, 3,4) and the pathogenicity of hyphal cells is stronger than that of yeast cells at the infected site. [12][13][14] The cAMP signal pathway is a regulation system of the transformation. Herrero et.…”

Section: Discussionmentioning

confidence: 99%

Hyphae Formation of Candida albicans Is Regulated by Polyamines

Ueno

Fukumatsu

Ogasawara

et al. 2004

Biological & Pharmaceutical Bulletin

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Candida albicans are opportunistic fungi which generally exist in the oral cavity, skin, vagina and intestinal organs, 1,2) and are dimorphic fungi which undergo a transition from the yeast form to the hyphal form depending on the growth conditions.3,4) They grow in yeast form at membranes and the surface of the skin, but in hyphae form at the deep-seated mycosis.Temperature, pH and Ca 2ϩ are known as external factors of the transformation.5-7) The hyphae transformation is induced by the activation of the MAP kinase and cAMP pathways, which are controlled by RAS protein. 8,9) Polyamines are synthesized from ornithine by ornithine decarboxylase (ODC) and known as inducers of adenylate cyclase. 10)In this report, we discovered that polyamines participated in the transformation of C. albicans, and the activation of adenylate cyclase was related to the transformation. MATERIALS AND METHODSOrganism and Growth Conditions C. albicans NIH A-207 strain was routinely grown in Sabouraud's medium (peptone 10 g, glucose 20 g and yeast extract 5 g, per liter). To induce hyphae formation, the cells were grown in RPMI1640 medium at 37°C.Reagents 1,4-Diamino-2-butanone (DAB) was pur-The Amount of Polyamines in C. albicans C. albicans cells (1ϫ10 5 cells/ml in RPMI1640) were incubated with DAB (0, 960 mM) in 5% CO 2 at 37°C for 1 and 3 h. Cells were washed twice with sterile water and disrupted with a Mini-Beadbeater (diameter of glass beads, 0.3 mm, Central Scientific Commerce, Inc.). Total proteins in the supernatant were analyzed at 280 nm and polyamines levels were determined using a Labosearch polyamine auto (A and T Corp.).Yeast Induction of C. albicans by Polyamine Synthesis Inhibitor C. albicans cells were adjusted to 1ϫ10 5 cells/ml in RPMI1640. DAB (0, 30, 60, 120, 240, 480, 960 mM) was added and incubated in 5% CO 2 at 37°C for 3 h. The ratio of hyphae cells was counted microscopically.Reverse Transcription-Polymerase Chain Reaction (RT-PCR) Gene arrangement participated in the hyphae formation of C. albicans referenced using the Entrez System of the National Center for Biotechnology Information (U.S.A.). PCR primers were designed using the Search Launcher in the Human Genome Sequencing Center (U.S.A.). C. albicans cells (1ϫ10 5 cells/ml in RPMI1640) were incubated with DAB (0, 960 mM) in 5% CO 2 at 37°C for 3 h. The cells were washed twice with sterile water. The cDNA library of the cells was synthesized with a Cells-tocDNA kit (Ambion Inc., U.S.A.). PCR reaction was conducted with a KOD-plus kit (Toyobo Co., Ltd.). Primers used in this assay are shown in Table 1. PCR products were analyzed using an Agilent 2100 Bioanalyzer (Agilent Technologies). The result was shown as a relative expression of mRNA compared with that of ACT1 (actin) as described by McCreach's method. 11)cAMP Concentration in C. albicans C. albicans cells (1ϫ10 5 cells/ml in RPMI1640) were incubated with DAB (0, 960 mM) in 5% CO 2 at 37°C for 3 h. Cells were washed twice with sterile water and disrupted with a Mini-Beadbeater. Total proteins in the s...

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Contact sensing inCandida albicans: a possible aid to epithelial penetration

Cited by 110 publications

References 19 publications

Yeasts in Apical Periodontitis

Yeasts in Apical Periodontitis

Oral Colonization By Candida Albicans

Hyphae Formation of Candida albicans Is Regulated by Polyamines

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