Differential increase in cytoplasmic pH at bud and germ tube formation in Candida albicans: studies of a nongerminative variant

1994 ◽  
Vol 40 (9) ◽  
pp. 720-723 ◽  
Author(s):  
Simminder Kaur ◽  
Prashant Mishra
Keyword(s):  
Candida Albicans ◽  
Cell Differentiation ◽  
Germ Tube ◽  
Tube Formation ◽  
Morphological Transition ◽  
Cytoplasmic Ph ◽  
Wild Type ◽  
Bud Formation ◽  
Differential Increase ◽  
Intracellular Alkalinization

The changes in cytoplasmic pH (pHi) accompanying the morphological transition of Candida albicans were studied using a nongerminative variant. A transient cytoplasmic alkalinization at the time of evagination was observed in both the variant and its parent. Under zinc-deficient conditions the wild-type cells that formed buds at pH 4.5 and mycelia at pH 6.5 showed an increase in pHi of 0.58 and 0.12 pH units, respectively. Under similar conditions the pHi of the nongerminative variant that formed buds at both pH 4.5 and 6.5 increased by 0.66 and 0.40 pH units, respectively, suggesting that a greater magnitude of increase in pHi at the time of evagination is probably needed for bud formation. These results provide evidence for a correlation between intracellular alkalinization and time of cell differentiation in C. albicans.Key words: C. albicans, cytoplasmic pH, morphogenesis, nongerminative variant.

ALS3 and ALS8 represent a single locus that encodes a Candida albicans adhesin; functional comparisons between Als3p and Als1p

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2415-2428 ◽  
Author(s):  
Xiaomin Zhao ◽  
Soon-Hwan Oh ◽  
Georgina Cheng ◽  
Clayton B. Green ◽  
Jennifer A. Nuessen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Germ Tube ◽  
Fluorescent Protein ◽  
Mutational Analysis ◽  
Oral Candidiasis ◽  
Tube Formation ◽  
Single Locus ◽  
Wild Type ◽  
Mutant Strains ◽  
Encoded Proteins

The ALS (agglutinin-like sequence) gene family of Candida albicans encodes eight cell-surface glycoproteins, some of which are involved in adherence to host surfaces. A mutational analysis of each ALS gene is currently being performed to deduce the functions of the encoded proteins and to better understand the role of these proteins in C. albicans biology and pathogenesis. This paper describes construction of an als3/als3 mutant and comparison of its phenotype to an als1/als1 strain. Efforts to disrupt ALS3 indicated that the gene could be deleted in two transformation steps, suggesting that the gene is encoded by a single locus and that the ALS3-like locus, ALS8, does not exist. Strains lacking ALS3 or ALS1 did not exhibit a defect in germ tube formation when grown in RPMI 1640 medium, but the als1/als1 mutant formed significantly fewer germ tubes in Lee medium. Analysis of ALS3 and ALS1 promoter activity using green fluorescent protein (GFP) reporter strains and flow cytometry showed that when cells are placed into medium that promotes germ tube formation, ALS1 is transcribed prior to ALS3. Comparison of the mutant strains in adhesion assays showed that the als3/als3 strain was defective in adhesion to both human umbilical vein endothelial cells (HUVEC) and buccal epithelial cells (BEC), but not to fibronectin-coated plastic plates. In contrast, the als1/als1 strain showed decreased adherence to HUVEC, but adherence to BEC and fibronectin were the same as wild-type controls. Inoculation of the buccal reconstituted human epithelium (RHE) model of oral candidiasis with the mutant strains showed nearly a total lack of adhesion and epithelial destruction by the als3/als3 mutant while the als1/als1 strain showed only a slightly reduced degree of epithelial destruction compared to the wild-type control. Adhesion data presented here suggest that, in the assays performed, loss of Als3p affects C. albicans adhesion more than loss of Als1p. Collectively, these results demonstrate functional similarities and differences between Als1p and Als3p, and suggest the potential for more complex interrelationships between the ALS genes and their encoded proteins.

A putative dual-specific protein phosphatase encoded by YVH1 controls growth, filamentation and virulence in Candida albicans

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2223-2232 ◽  
Author(s):  
Nozomu Hanaoka ◽  
Takashi Umeyama ◽  
Keigo Ueno ◽  
Kenji Ueda ◽  
Teruhiko Beppu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Candida Albicans ◽  
Cell Cycle Progression ◽  
Germ Tube ◽  
Hyphal Growth ◽  
Tube Formation ◽  
Yeast Cells ◽  
Nucleotide Polymorphisms ◽  
Wild Type ◽  
Cycle Progression

In response to stimulants, such as serum, the yeast cells of the opportunistic fungal pathogen Candida albicans form germ tubes, which develop into hyphae. Yvh1p, one of the 29 protein phosphatases encoded in the C. albicans genome, has 45 % identity with the dual-specific phosphatase Yvh1p of the model yeast Saccharomyces cerevisiae. In this study, Yvh1p expression was not observed during the initial step of germ tube formation, although Yvh1p was expressed constitutively in cell cycle progression of yeast or hyphal cells. In an attempt to analyse the function of Yvh1p phosphatase, the complete ORFs of both alleles were deleted by replacement with hph200–URA3–hph200 and ARG4. Although YVH1 has nine single-nucleotide polymorphisms in its coding sequence, both YVH1 alleles were able to complement the YVH1 gene disruptant. The vegetative growth of Δyvh1 was significantly slower than the wild-type. The hyphal growth of Δyvh1 on agar, or in a liquid medium, was also slower than the wild-type because of the delay in nuclear division and septum formation, although germ tube formation was similar between the wild-type and the disruptant. Despite the slow hyphal growth, the expression of several hypha-specific genes in Δyvh1 was not delayed or repressed compared with that of the wild-type. Infection studies using mouse models revealed that the virulence of Δyvh1 was less than that of the wild-type. Thus, YVH1 contributes to normal vegetative yeast or hyphal cell cycle progression and pathogenicity, but not to germ tube formation.

scholarly journals Arginine-Induced Germ Tube Formation in Candida albicans Is Essential for Escape from Murine Macrophage Line RAW 264.7

2009 ◽  
Vol 77 (4) ◽  
pp. 1596-1605 ◽  
Author(s):  
Suman Ghosh ◽  
Dhammika H. M. L. P. Navarathna ◽  
David D. Roberts ◽  
Jake T. Cooper ◽  
Audrey L. Atkin ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Pathogen ◽  
Germ Tube ◽  
Tube Formation ◽  
Raw 264.7 ◽  
Dependent Manner ◽  
Wild Type ◽  
Normal Flora ◽  
Opportunistic Fungal Pathogen ◽  
Germ Tubes

ABSTRACT The opportunistic fungal pathogen Candida albicans is a part of the normal flora but it also causes systemic candidiasis if it reaches the bloodstream. Upon being phagocytized by macrophages, an important component of innate immunity, C. albicans rapidly upregulates a set of arginine biosynthetic genes. Arginine, urea, and CO2 induced hyphae in a density-dependent manner in wild-type, cph1/cph1, and rim101/rim101 strains but not in efg1/efg1 or cph1/cph1 efg1/efg1 strains. Arginase (Car1p) converts arginine to urea, which in turn is degraded by urea amidolyase (Dur1,2p) to produce CO2, a signal for hyphal switching. We used a dur1,2/dur1,2 mutant (KWN6) and the complemented strain, KWN8 (dur1,2/dur1,2::DUR1,2/DUR1,2) to study germ tube formation. KWN6 could not make germ tubes in the presence of arginine or urea but did in the presence of 5% CO2, which bypasses Dur1,2p. We also tested the effect of arginine on the interaction between the macrophage line RAW 264.7 and several strains of C. albicans. Arginine activated an Efg1p-dependent yeast-to-hypha switch, enabling wild-type C. albicans and KWN8 to escape from macrophages within 6 h, whereas KWN6 was defective in this regard. Additionally, two mutants that cannot synthesize arginine, BWP17 and SN152, were defective in making hyphae inside the macrophages, whereas the corresponding arginine prototrophs, DAY286 and SN87, formed germ tubes and escaped from macrophages. Therefore, metabolism of arginine by C. albicans controls hyphal switching and provides an important mechanism for escaping host defense.

scholarly journals CAP1, an Adenylate Cyclase-Associated Protein Gene, Regulates Bud-Hypha Transitions, Filamentous Growth, and Cyclic AMP Levels and Is Required for Virulence of Candida albicans

2001 ◽  
Vol 183 (10) ◽  
pp. 3211-3223 ◽  
Author(s):  
Yong-Sun Bahn ◽  
Paula Sundstrom
Keyword(s):  
Candida Albicans ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Germ Tube ◽  
Filamentous Growth ◽  
Tube Formation ◽  
Camp Signaling ◽  
Solid Media ◽  
Opportunistic Fungal Pathogen ◽  
Camp Levels

ABSTRACT In response to a wide variety of environmental stimuli, the opportunistic fungal pathogen Candida albicans exits the budding cycle, producing germ tubes and hyphae concomitant with expression of virulence genes, such as that encoding hyphal wall protein 1 (HWP1). Biochemical studies implicate cyclic AMP (cAMP) increases in promoting bud-hypha transitions, but genetic evidence relating genes that control cAMP levels to bud-hypha transitions has not been reported. Adenylate cyclase-associated proteins (CAPs) of nonpathogenic fungi interact with Ras and adenylate cyclase to increase cAMP levels under specific environmental conditions. To initiate studies on the relationship between cAMP signaling and bud-hypha transitions in C. albicans, we identified, cloned, characterized, and disrupted the C. albicans CAP1 gene. C. albicans strains with inactivated CAP1 budded in conditions that led to germ tube formation in isogenic strains withCAP1. The addition of 10 mM cAMP and dibutyryl cAMP promoted bud-hypha transitions and filamentous growth in thecap1/cap1 mutant in liquid and solid media, respectively, showing clearly that cAMP promotes hypha formation in C. albicans. Increases in cytoplasmic cAMP preceding germ tube emergence in strains having CAP1 were markedly diminished in the budding cap1/cap1 mutant. C. albicans strains with deletions of both alleles ofCAP1 were avirulent in a mouse model of systemic candidiasis. The avirulence of a germ tube-deficientcap1/cap1 mutant coupled with the role of Cap1 in regulating cAMP levels shows that the Cap1-mediated cAMP signaling pathway is required for bud-hypha transitions, filamentous growth, and the pathogenesis of candidiasis.

Candida albicans growth and germ tube formation can be inhibited by simple diphenyl diselenides [(PhSe)2, (MeOPhSe)2, (p-Cl-PhSe)2, (F3CPhSe)2] and diphenyl ditelluride

Mycoses ◽  
2010 ◽  
Vol 54 (6) ◽  
pp. 506-513 ◽  
Author(s):  
Isabela Bueno Rosseti ◽  
Caroline Wagner ◽  
Roselei Fachinetto ◽  
Paulo Taube Junior ◽  
Maricilia Silva Costa
Keyword(s):  
Candida Albicans ◽  
Germ Tube ◽  
Tube Formation ◽  
Diphenyl Ditelluride

Farnesol restores wild-type colony morphology to 96% of Candida albicans colony morphology variants recovered following treatment with mutagens

Genome ◽  
2006 ◽  
Vol 49 (4) ◽  
pp. 346-353 ◽  
Author(s):  
Ellen C Jensen ◽  
Jacob M Hornby ◽  
Nicole E Pagliaccetti ◽  
Chuleeon M Wolter ◽  
Kenneth W Nickerson ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Environmental Conditions ◽  
Budding Yeast ◽  
Colony Morphology ◽  
Morphological Transition ◽  
Strongly Correlated ◽  
Wild Type ◽  
Hyphal Morphology

Candida albicans is a diploid fungus that undergoes a morphological transition between budding yeast, hyphal, and pseudohyphal forms. The morphological transition is strongly correlated with virulence and is regulated in part by quorum sensing. Candida albicans produces and secretes farnesol that regulates the yeast to mycelia morphological transition. Mutants that fail to synthesize or respond to farnesol could be locked in the filamentous mode. To test this hypothesis, a collection of C. albicans mutants were isolated that have altered colony morphologies indicative of the presence of hyphal cells under environmental conditions where C. albicans normally grows only as yeasts. All mutants were characterized for their ability to respond to farnesol. Of these, 95.9% fully or partially reverted to wild-type morphology on yeast malt (YM) agar plates supplemented with farnesol. All mutants that respond to farnesol regained their hyphal morphology when restreaked on YM plates without farnesol. The observation that farnesol remedial mutants are so common (95.9%) relative to mutants that fail to respond to farnesol (4.1%) suggests that farnesol activates and (or) induces a pathway that can override many of the morphogenesis defects in these mutants. Additionally, 9 mutants chosen at random were screened for farnesol production. Two mutants failed to produce detectable levels of farnesol.Key words: farnesol-remedial mutants, farnesol-sensing mutants, farnesol-synthesis mutants, quorum sensing, Candida albicans, morphological transition.

scholarly journals Satureja khuzistanica Jamzad essential oil and its anti-candidal activities against clinical isolates of Candida albicans isolated from women with candidiasis

Infectio ◽  
2018 ◽  
Vol 23 (1) ◽  
pp. 16 ◽  
Author(s):  
Mohaddese Mahboubi ◽  
Bahareh Attaran
Keyword(s):  
Candida Albicans ◽  
Essential Oil ◽  
Germ Tube ◽  
Folk Medicine ◽  
Tube Formation ◽  
Clinical Isolates ◽  
Analgesic Agent ◽  
Aerial Parts ◽  
Main Component ◽  
Cytoplasmic Structures

Satureja khuzistanica Jamzad is known as antiseptic and analgesic agent in folk medicine. The aim of this investigation was to evaluate the anti-candidal activity of S. khuzistanica aerial parts essential oil against clinical isolates of Candida albicans, which were isolated from women with chronic recurrent candidiasis. For this purpose, the chemical composition of hydro-distilled essential oil was determined by GC and GC-MS analysis. Then, the anti-candidal activity of essential oil and its main component (carvacrol) were determined. Carvacrol (94.1%) was the main component of essential oil, followed by β-bisabolene, p-cymene and γ-terpinene. S. khuzistanica essential oil had strong anti-candidal activity against clinical isolates of C. albicans via inhibition of germ tube formation and induction the huge punctures in the cytoplasmic structures. The cell membranes were intact in presence of essential oil or carvacrol. S. khuzistanica essential oil as the main source of carvacrol can be used for treatment of C. albicans related infections.

scholarly journals Enzymes of N-Acetylglucosamine Metabolism during Germ-tube Formation in Candida albicans

Microbiology ◽  
1982 ◽  
Vol 128 (10) ◽  
pp. 2319-2326 ◽  
Author(s):  
P. Gopal ◽  
P. A. Sullivan ◽  
M. G. Shepherd
Keyword(s):  
Candida Albicans ◽  
Germ Tube ◽  
Tube Formation
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