Candida Research Today is a free monthly online journal that collates and summarizes the latest research about Candida, including details on thrush infections, yeast, diet, treatment, symptoms.

An internal polarity landmark is important for externally induced hyphal behaviors in Candida albicans.

Brand A, Vacharaksa A, Bendel C, Norton J, Haynes P, Henry-Stanley M, Wells C, Ross K, Gow NA, Gale CA

Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom.

Directional growth is a function of polarized cells such as neurites, pollen tubes, and fungal hyphae. Correct orientation of the extending cell tip depends on signaling pathways and effectors that mediate asymmetric responses to specific environmental cues. In the hyphal form of the eukaryotic fungal pathogen Candida albicans, these responses include thigmotropism and galvanotropism (hyphal turning in response to changes in substrate topography and imposed electrical fields, respectively) and penetration into semisolid substrates. During vegetative growth in C. albicans, as in the model yeast Saccharomyces cerevisiae, the Ras-like GTPase Rsr1 mediates internal cellular cues to position new buds in a prespecified pattern on the mother cell cortex. Here, we demonstrate that Rsr1 is also important for hyphal tip orientation in response to the external environmental cues that induce thigmotropic and galvanotropic growth. In addition, Rsr1 is involved in hyphal interactions with epithelial cells in vitro and its deletion diminishes the hyphal invasion of kidney tissue during systemic infection. Thus, Rsr1, an internal polarity landmark in yeast, is also involved in polarized growth responses to asymmetric environmental signals, a paradigm that is different from that described for the homologous protein in S. cerevisiae. Rsr1 may thereby contribute to the pathogenesis of C. albicans infections by influencing hyphal tip responses triggered by interaction with host tissues.

Published 8 April 2008 in Eukaryot Cell, 7(4): 712-20.
Full-text of this article is available online (may require subscription).

Articles on Candida published 8 April 2008:

Carnitine-dependent transport of acetyl coenzyme A in Candida albicans is essential for growth on nonfermentable carbon sources and contributes to biofilm formation.   Eukaryot Cell, 7(4): 610-8.

In eukaryotes, acetyl coenzyme A (acetyl-CoA) produced during peroxisomal fatty acid beta-oxidation needs to be transported to mitochondria for further metabolism. Two parallel pathways for acetyl-CoA transport have been identified in Saccharomyces cerevisiae; one is dependent on peroxisomal citrate synthase (Cit), while the other requires peroxisomal and mitochondrial carnitine acetyltransferase (Cat) activities. Here we show that the human fungal pathogen Candida albicans lacks peroxisomal ... [Abstract] [Full-text]

Articles on Candida published 4 April 2008:

Survey of vaginal-flora Candida species isolates from women of different age groups by use of species-specific PCR detection.   J Clin Microbiol, 46(4): 1501-3.

A retrospective survey of 93,775 samples testing positive in Candida species-specific PCR tests performed on cervicovaginal swabs over a 4-year period demonstrated consistent yearly distributions of Candida albicans (89%), C. glabrata (7.9%), C. parapsilosis (1.7%), and C. tropicalis (1.4%). However, the species distributions among different age groups revealed increases in the percentages of non-albicans species with increases in age. [Abstract] [Full-text]

Rapid and accurate identification of Candida albicans isolates by use of PNA FISHFlow.   J Clin Microbiol, 46(4): 1537-40.

We developed the simple, rapid (1 h), and accurate PNA FISH(Flow) method for the identification of Candida albicans. The method exploits unique in solution in situ hybridization conditions under which the cells are simultaneously fixed and hybridized. This method facilitates the accurate identification of clinical yeast isolates using two scoring techniques: flow cytometry and fluorescence microscopy. [Abstract] [Full-text]

Articles on Candida published 2 April 2008:

Fluconazole prophylaxis in extremely low birth weight neonates reduces invasive candidiasis mortality rates without emergence of fluconazole-resistant Candida species.   Pediatrics, 121(4): 703-10.

OBJECTIVE: We evaluated the impact of fluconazole prophylaxis for extremely low birth weight infants on invasive candidiasis incidence, invasive candidiasis-related mortality rates, and fluconazole susceptibility of Candida isolates. METHODS: Extremely low birth weight infants <5 days of age, except those with liver dysfunction, were eligible for fluconazole prophylaxis. NICU infants (all birth weights) with invasive candidiasis between April 2002 and March 2006 were compared with those with ... [Abstract] [Full-text]

Articles on Candida published 25 March 2008:

D-Erythroascorbic acid activates cyanide-resistant respiration in Candida albicans.   Biochem Biophys Res Commun, 369(2): 401-6.

Higher plants, protists and fungi possess cyanide-resistant respiratory pathway, which is mediated by alternative oxidase (AOX). The activity of AOX has been found to be dependent on several regulatory mechanisms including gene expression and posttranslational regulation. In the present study, we report that the presence of cyanide in culture medium remarkably retarded the growth of alo1/alo1 mutant of Candida albicans, which lacks d-arabinono-1,4-lactone oxidase (ALO) that catalyzes the final ... [Abstract] [Full-text]

Articles on Candida published 20 March 2008:

Genotypic analysis of Candida albicans isolates obtained from removable prosthesis wearers.   Lett Appl Microbiol, 46(4): 445-9.

AIMS: To assess of the genotypic diversity of Candida albicans isolated from removable prosthesis wearers, with and without denture-related stomatitis (DRS). The occurrence of different genotypes in pathological and control cases was investigated. METHODS AND RESULTS: One hundred and sixty-four isolates of C. albicans obtained from different oral cavity locations were compared by randomly amplified polymorphic DNA (RAPD). The coherence of this analysis was confirmed by genotyping a selected ... [Abstract] [Full-text]

Articles on Candida published 19 March 2008:

Combined inactivation of the Candida albicans GPR1 and TPS2 genes results in avirulence in a mouse model for systemic infection.   Infect Immun, 76(4): 1686-94.

Inhibition of the biosynthesis of trehalose, a well-known stress protectant in pathogens, is an interesting approach for antifungal or antibacterial therapy. Deletion of TPS2, encoding trehalose-6-phosphate (T6P) phosphatase, results in strongly reduced virulence of Candida albicans due to accumulation of T6P instead of trehalose in response to stress. To further aggravate the deregulation in the pathogen, we have additionally deleted the GPR1 gene, encoding the nutrient receptor that activates ... [Abstract] [Full-text]

Efficacy of a new formulation of amphotericin B in a murine model of disseminated infection by Candida glabrata.   J Antimicrob Chemother, 61(4): 880-3.

OBJECTIVES: Amphotericin B poly-aggregates are a new formulation of amphotericin B, which can be obtained cheaply. In this study, we tested the efficacy of this new formulation for treating a disseminated infection by Candida glabrata in a murine model. METHODS: Mice were rendered neutropenic by intraperitoneal cyclophosphamide and intravenous 5-fluorouracil administration and infected intravenously with 2 x 10(8) cfu of C. glabrata. The efficacy of the new formulation of amphotericin B was ... [Abstract] [Full-text]

© 2004-2008 Candida Research Today. All Rights Reserved.