Role of the Candida albicans MNN1 gene family in cell wall structure and virulence

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Bates, S.; Hall, R.A.; Cheetham, J.; Netea, M.G.; MacCallum, D.M.; Brown, A.J.; Odds, F.C.; Gow, N.A.

2013-01-01

BACKGROUND: The Candida albicans cell wall is the first point of contact with the host, and its outer surface is heavily enriched in mannoproteins modified through the addition of N- and O-mannan. Previous work, using mutants with gross defects in glycosylation, has clearly identified the importance

Cell wall carbohydrates content of pathogenic Candida albicans strain morphological forms.

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Staniszewska, Monika; Bondaryk, Małgorzata; Rabczenko, Daniel; Smoleńska-Sym, Gabriela; Kurzatkowski, Wiesław

2013-01-01

The study evaluated the cell wall carbohydrates fraction in blastoconidia grown in YEPD medium at 30 degrees C and in the conglomerate of true hyphae grown in human serum at 37 degrees C. The clinical isolate obtained from a child with widespread C. albicans infection was used in the study. The cells were broken with glass beads, centrifuged to harvest the cell wall followed by subjection to TFA hydrolysis and in the result of that released monosaccharides were detected by HPAEC-PAD. Both, serum and temperature conditions (37 degrees C) affected germination process influencing the cell wall carbohydrates content when incubation in serum was prolonged from 1 to 18 h. The mannan content of blastoconidia was almost twofold higher compared to filamentous forms (149.25 +/- 299.24 vs 77.26 +/- 122.07). The glucan content was threefold lower in blastoconidia compared to hyphae (251.86 +/- 243.44 vs 755.81 +/- 1299.30). The chitin level was fourfold lower in blastoconidia compared to filaments (23.86 +/- 54.09 vs 106.29 +/- 170.12). The reason for the differences in the carbohydrates content may be related to type of morphology induced in different environmental conditions. Among tested carbohydrates, glucan appeared to be present in appreciably larger amounts in both tested morphological fractions. The ultrastructure of the blastoconidial cell wall revealed striking differences compared to the hyphae indicating the carbohydrates content alterations for wall assembly during hyphal growth at alkaline pH and temp. 37 degrees C. The study provided evidence for the relationship between morphogenesis, cell-cell adhesion induced by serum and changes in the level of carbohydrates content.

The N-Linked Outer Chain Mannans and the Dfg5p and Dcw1p Endo-α-1,6-Mannanases Are Needed for Incorporation of Candida albicans Glycoproteins into the Cell Wall

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Ao, Jie; Chinnici, Jennifer L.; Maddi, Abhiram

2015-01-01

A biochemical pathway for the incorporation of cell wall protein into the cell wall of Neurospora crassa was recently proposed. In this pathway, the DFG-5 and DCW-1 endo-α-1,6-mannanases function to covalently cross-link cell wall protein-associated N-linked galactomannans, which are structurally related to the yeast outer chain mannans, into the cell wall glucan-chitin matrix. In this report, we demonstrate that the mannosyltransferase enzyme Och1p, which is needed for the synthesis of the N-linked outer chain mannan, is essential for the incorporation of cell wall glycoproteins into the Candida albicans cell wall. Using endoglycosidases, we show that C. albicans cell wall proteins are cross-linked into the cell wall via their N-linked outer chain mannans. We further demonstrate that the Dfg5p and Dcw1p α-1,6-mannanases are needed for the incorporation of cell wall glycoproteins into the C. albicans cell wall. Our results support the hypothesis that the Dfg5p and Dcw1p α-1,6-mannanases incorporate cell wall glycoproteins into the C. albicans cell wall by cross-linking outer chain mannans into the cell wall glucan-chitin matrix. PMID:26048011

The MP65 gene is required for cell wall integrity, adherence to epithelial cells and biofilm formation in Candida albicans

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Girolamo Antonietta

2011-05-01

Full Text Available Abstract Background The MP65 gene of Candida albicans (orf19.1779 encodes a putative β-glucanase mannoprotein of 65 kDa, which plays a main role in a host-fungus relationship, morphogenesis and pathogenicity. In this study, we performed an extensive analysis of a mp65Δ mutant to assess the role of this protein in cell wall integrity, adherence to epithelial cells and biofilm formation. Results The mp65Δ mutant showed a high sensitivity to a range of cell wall-perturbing and degrading agents, especially Congo red, which induced morphological changes such as swelling, clumping and formation of hyphae. The mp65Δ mutant showed an activation of two MAPKs (Mkc1p and Cek1p, a high level of expression of two stress-related genes (DDR48 and SOD5, and a modulated expression of β-glucan epitopes, but no gross changes in cell wall polysaccharide composition. Interestingly, the mp65Δ mutant displayed a marked reduction in adhesion to BEC and Caco-2 cells and severe defects in biofilm formation when compared to the wild type. All of the mentioned properties were totally or partially recovered in a revertant strain, demonstrating the specificity of gene deletion. Conclusions We demonstrate that the MP65 gene of Candida albicans plays a significant role in maintaining cell wall integrity, as well as in adherence to epithelia and biofilm formation, which are major virulence attributes of this fungus.

Use of green fluorescent protein fusions to analyse the N- and C-terminal signal peptides of GPI-anchored cell wall proteins in Candida albicans.

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Mao, Yuxin; Zhang, Zimei; Wong, Brian

2003-12-01

Glycophosphatidylinositol (GPI)-anchored proteins account for 26-35% of the Candida albicans cell wall. To understand the signals that regulate these proteins' cell surface localization, green fluorescent protein (GFP) was fused to the N- and C-termini of the C. albicans cell wall proteins (CWPs) Hwp1p, Als3p and Rbt5p. C. albicans expressing all three fusion proteins were fluorescent at the cell surface. GFP was released from membrane fractions by PI-PLC and from cell walls by beta-glucanase, which implied that GFP was GPI-anchored to the plasma membrane and then covalently attached to cell wall glucans. Twenty and 25 amino acids, respectively, from the N- and C-termini of Hwp1p were sufficient to target GFP to the cell surface. C-terminal substitutions that are permitted by the omega rules (G613D, G613N, G613S, G613A, G615S) did not interfere with GFP localization, whereas some non-permitted substitutions (G613E, G613Q, G613R, G613T and G615Q) caused GFP to accumulate in intracellular ER-like structures and others (G615C, G613N/G615C and G613D/G615C) did not. These results imply that (i) GFP fusions can be used to analyse the N- and C-terminal signal peptides of GPI-anchored CWPs, (ii) the omega amino acid in Hwp1p is G613, and (iii) C can function at the omega+2 position in C. albicans GPI-anchored proteins.

Cell wall damage and oxidative stress in Candida albicans ATCC10231 and Aspergillus niger caused by palladium nanoparticles.

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Athie-García, Martha Samira; Piñón-Castillo, Hilda Amelia; Muñoz-Castellanos, Laila Nayzzel; Ulloa-Ogaz, Ana Laura; Martínez-Varela, Perla Ivonne; Quintero-Ramos, Armando; Duran, Robert; Murillo-Ramirez, José Guadalupe; Orrantia-Borunda, Erasmo

2018-04-01

In this work the toxic effect of Palladium nanoparticles (PdNPs) was investigated in two eukaryotic cell models, Candida albicans and Aspergillus niger. PdNPs were synthesized by chemical reduction method, obtaining spherical NPs with a primary size ranging from 3 to 15 nm. PdNPs showed a hydrodynamic size of 1548 nm in Lee's minimum media. Minimal inhibitory concentration was determined at 200 and 250 ppm for Candida albicans and Aspergillus niger respectively, revealing a significant cell growth inhibition (ANOVA and tukey analysis, α = 0.5). Reactive Oxygen Species levels were increased in both microorganisms. Confocal, scanning and transmission electron microscopy studies revealed cell wall damage and cellular morphology changes, induced by the interaction of PdNPs, in both microorganisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Endoplasmic reticulum-derived reactive oxygen species (ROS) is involved in toxicity of cell wall stress to Candida albicans.

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Yu, Qilin; Zhang, Bing; Li, Jianrong; Zhang, Biao; Wang, Honggang; Li, Mingchun

2016-10-01

The cell wall is an important cell structure in both fungi and bacteria, and hence becomes a common antimicrobial target. The cell wall-perturbing agents disrupt synthesis and function of cell wall components, leading to cell wall stress and consequent cell death. However, little is known about the detailed mechanisms by which cell wall stress renders fungal cell death. In this study, we found that ROS scavengers drastically attenuated the antifungal effect of cell wall-perturbing agents to the model fungal pathogen Candida albicans, and these agents caused remarkable ROS accumulation and activation of oxidative stress response (OSR) in this fungus. Interestingly, cell wall stress did not cause mitochondrial dysfunction and elevation of mitochondrial superoxide levels. Furthermore, the iron chelator 2,2'-bipyridyl (BIP) and the hydroxyl radical scavengers could not attenuate cell wall stress-caused growth inhibition and ROS accumulation. However, cell wall stress up-regulated expression of unfold protein response (UPR) genes, enhanced protein secretion and promoted protein folding-related oxidation of Ero1, an important source of ROS production. These results indicated that oxidation of Ero1 in the endoplasmic reticulum (ER), rather than mitochondrial electron transport and Fenton reaction, contributed to cell wall stress-related ROS accumulation and consequent growth inhibition. Our findings uncover a novel link between cell wall integrity (CWI), ER function and ROS production in fungal cells, and shed novel light on development of strategies promoting the antifungal efficacy of cell wall-perturbing agents against fungal infections. Copyright © 2016 Elsevier Inc. All rights reserved.

The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans

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Barbara Koch

2017-12-01

Full Text Available The interactions of mitochondria with the endoplasmic reticulum (ER are crucial for maintaining proper mitochondrial morphology, function and dynamics. This enables cells to utilize their mitochondria optimally for energy production and anabolism, and it further provides for metabolic control over developmental decisions. In fungi, a key mechanism by which ER and mitochondria interact is via a membrane tether, the protein complex ERMES (ER-Mitochondria Encounter Structure. In the model yeast Saccharomyces cerevisiae, the mitochondrial GTPase Gem1 interacts with ERMES, and it has been proposed to regulate its activity. Here we report on the first characterization of Gem1 in a human fungal pathogen. We show that in Candida albicans Gem1 has a dominant role in ensuring proper mitochondrial morphology, and our data is consistent with Gem1 working with ERMES in this role. Mitochondrial respiration and steady state cellular phospholipid homeostasis are not impacted by inactivation of GEM1 in C. albicans. There are two major virulence-related consequences of disrupting mitochondrial morphology by GEM1 inactivation: C. albicans becomes hypersusceptible to cell wall stress, and is unable to grow invasively. In the gem1Δ/Δ mutant, it is specifically the invasive capacity of hyphae that is compromised, not the ability to transition from yeast to hyphal morphology, and this phenotype is shared with ERMES mutants. As a consequence of the hyphal invasion defect, the gem1Δ/Δ mutant is drastically hypovirulent in the worm infection model. Activation of the mitogen activated protein (MAP kinase Cek1 is reduced in the gem1Δ/Δ mutant, and this function could explain both the susceptibility to cell wall stress and lack of invasive growth. This result establishes a new, respiration-independent mechanism of mitochondrial control over stress signaling and hyphal functions in C. albicans. We propose that ER-mitochondria interactions and the ER

The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans.

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Koch, Barbara; Tucey, Timothy M; Lo, Tricia L; Novakovic, Stevan; Boag, Peter; Traven, Ana

2017-01-01

The interactions of mitochondria with the endoplasmic reticulum (ER) are crucial for maintaining proper mitochondrial morphology, function and dynamics. This enables cells to utilize their mitochondria optimally for energy production and anabolism, and it further provides for metabolic control over developmental decisions. In fungi, a key mechanism by which ER and mitochondria interact is via a membrane tether, the protein complex ERMES (ER-Mitochondria Encounter Structure). In the model yeast Saccharomyces cerevisiae , the mitochondrial GTPase Gem1 interacts with ERMES, and it has been proposed to regulate its activity. Here we report on the first characterization of Gem1 in a human fungal pathogen. We show that in Candida albicans Gem1 has a dominant role in ensuring proper mitochondrial morphology, and our data is consistent with Gem1 working with ERMES in this role. Mitochondrial respiration and steady state cellular phospholipid homeostasis are not impacted by inactivation of GEM1 in C. albicans . There are two major virulence-related consequences of disrupting mitochondrial morphology by GEM1 inactivation: C. albicans becomes hypersusceptible to cell wall stress, and is unable to grow invasively. In the gem1 Δ / Δ mutant, it is specifically the invasive capacity of hyphae that is compromised, not the ability to transition from yeast to hyphal morphology, and this phenotype is shared with ERMES mutants. As a consequence of the hyphal invasion defect, the gem1 Δ / Δ mutant is drastically hypovirulent in the worm infection model. Activation of the mitogen activated protein (MAP) kinase Cek1 is reduced in the gem1 Δ / Δ mutant, and this function could explain both the susceptibility to cell wall stress and lack of invasive growth. This result establishes a new, respiration-independent mechanism of mitochondrial control over stress signaling and hyphal functions in C. albicans . We propose that ER-mitochondria interactions and the ER-Mitochondria Organizing

Targeted changes of the cell wall proteome influence Candida albicans ability to form single- and multi-strain biofilms.

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Vitor Cabral

2014-12-01

Full Text Available Biofilm formation is an important virulence trait of the pathogenic yeast Candida albicans. We have combined gene overexpression, strain barcoding and microarray profiling to screen a library of 531 C. albicans conditional overexpression strains (∼10% of the genome for genes affecting biofilm development in mixed-population experiments. The overexpression of 16 genes increased strain occupancy within a multi-strain biofilm, whereas overexpression of 4 genes decreased it. The set of 16 genes was significantly enriched for those encoding predicted glycosylphosphatidylinositol (GPI-modified proteins, namely Ihd1/Pga36, Phr2, Pga15, Pga19, Pga22, Pga32, Pga37, Pga42 and Pga59; eight of which have been classified as pathogen-specific. Validation experiments using either individually- or competitively-grown overexpression strains revealed that the contribution of these genes to biofilm formation was variable and stage-specific. Deeper functional analysis of PGA59 and PGA22 at a single-cell resolution using atomic force microscopy showed that overexpression of either gene increased C. albicans ability to adhere to an abiotic substrate. However, unlike PGA59, PGA22 overexpression led to cell cluster formation that resulted in increased sensitivity to shear forces and decreased ability to form a single-strain biofilm. Within the multi-strain environment provided by the PGA22-non overexpressing cells, PGA22-overexpressing cells were protected from shear forces and fitter for biofilm development. Ultrastructural analysis, genome-wide transcript profiling and phenotypic analyses in a heterologous context suggested that PGA22 affects cell adherence through alteration of cell wall structure and/or function. Taken together, our findings reveal that several novel predicted GPI-modified proteins contribute to the cooperative behaviour between biofilm cells and are important participants during C. albicans biofilm formation. Moreover, they illustrate the power

A ReaxFF-based molecular dynamics study of the mechanisms of interactions between reactive oxygen plasma species and the Candida albicans cell wall

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Zhao, T.; Shi, L.; Zhang, Y. T.; Zou, L.; Zhang, L.

2017-10-01

Atmospheric pressure non-equilibrium plasmas have attracted significant attention and have been widely used to inactivate pathogens, yet the mechanisms underlying the interactions between plasma-generated species and bio-organisms have not been elucidated clearly. In this paper, reactive molecular dynamics simulations are employed to investigate the mechanisms of interactions between reactive oxygen plasma species (O, OH, and O2) and β-1,6-glucan (a model for the C. albicans cell wall) from a microscopic point of view. Our simulations show that O and OH species can break structurally important C-C and C-O bonds, while O2 molecules exhibit only weak, non-bonded interactions with β-1,6-glucan. Hydrogen abstraction from hydroxyl or CH groups occurs first in all bond cleavage mechanisms. This is followed by a cascade of bond cleavage and double bond formation events. These lead to the destruction of the fungal cell wall. O and OH have similar effects related to their bond cleavage mechanisms. Our simulation results provide fundamental insights into the mechanisms underlying the interactions between reactive oxygen plasma species and the fungal cell wall of C. albicans at the atomic level.

Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance.

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Ene, Iuliana V; Walker, Louise A; Schiavone, Marion; Lee, Keunsook K; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A R; Munro, Carol A; Brown, Alistair J P

2015-07-28

The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by

Antifungal Activity of Coumarin from Ageratum conyzoides L. Leaves on Candida albicans cells

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Gunawan Pamudji Widodo

2012-07-01

Full Text Available The aim of this study was to identify the antifungal activity of coumarin isolated from Ageratum conyzoides L. leaves and to observe its influence on Candida albicans cells by scanning electron microscope (SEM and transmission electron microscope (TEM. Antifungal activity testing by disk diffusion method showed coumarin was active toward pathogenic fungus, Candida albicans with the MIC value of coumarin of 125 g mL-1. The influence of this substance on C. albicans cells was observed by scanning and transmission electron microscopies. The result showed that this compound damaged the cell by pores formation on the cell wall. The death of cells occurred due to leakage and necrotic of cytoplasmic content.

The PHR Family: The Role of Extracellular Transglycosylases in Shaping Candida albicans Cells

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Laura Popolo

2017-10-01

Full Text Available Candida albicans is an opportunistic microorganism that can become a pathogen causing mild superficial mycosis or more severe invasive infections that can be life-threatening for debilitated patients. In the etiology of invasive infections, key factors are the adaptability of C. albicans to the different niches of the human body and the transition from a yeast form to hypha. Hyphal morphology confers high adhesiveness to the host cells, as well as the ability to penetrate into organs. The cell wall plays a crucial role in the morphological changes C. albicans undergoes in response to specific environmental cues. Among the different categories of enzymes involved in the formation of the fungal cell wall, the GH72 family of transglycosylases plays an important assembly role. These enzymes cut and religate β-(1,3-glucan, the major determinant of cell shape. In C. albicans, the PHR family encodes GH72 enzymes, some of which work in specific environmental conditions. In this review, we will summarize the work from the initial discovery of PHR genes to the study of the pH-dependent expression of PHR1 and PHR2, from the characterization of the gene products to the recent findings concerning the stress response generated by the lack of GH72 activity in C. albicans hyphae.

Accessibility and contribution to glucan masking of natural and genetically tagged versions of yeast wall protein 1 of Candida albicans.

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Granger, Bruce L

2018-01-01

Yeast wall protein 1 (Ywp1) is an abundant glycoprotein of the cell wall of the yeast form of Candida albicans, the most prevalent fungal pathogen of humans. Antibodies that bind to the polypeptide backbone of isolated Ywp1 show little binding to intact yeast cells, presumably because the Ywp1 epitopes are masked by the polysaccharides of the mannoproteins that form the outer layer of the cell wall. Rare cells do exhibit much greater anti-Ywp1 binding, however, and one of these was isolated and characterized. No differences were seen in its Ywp1, but it exhibited greater adhesiveness, sensitivity to wall perturbing agents, and exposure of its underlying β-1,3-glucan layer to external antibodies. The molecular basis for this greater epitope accessibility has not been determined, but has facilitated exploration of how these properties change as a function of cell growth and morphology. In addition, previously engineered strains with reduced quantities of Ywp1 in their cell walls were also found to have greater β-1,3-glucan exposure, indicating that Ywp1 itself contributes to the masking of wall epitopes, which may be important for understanding the anti-adhesive effect of Ywp1. Ectopic production of Ywp1 by hyphae, which reduces the adhesivity of these filamentous forms of C. albicans, was similarly found to reduce exposure of the β-1,3-glucan in their walls. To monitor Ywp1 in the cell wall irrespective of its accessibility, green fluorescent protein (Gfp) was genetically inserted into wall-anchored Ywp1 using a bifunctional cassette that also allowed production from a single transfection of a soluble, anchor-free version. The wall-anchored Ywp1-Gfp-Ywp1 accumulated in the wall of the yeast forms but not hyphae, and appeared to have properties similar to native Ywp1, including its adhesion-inhibiting effect. Some pseudohyphal walls also detectably accumulated this probe. Strains of C. albicans with tandem hemagglutinin (HA) epitopes inserted into wall

Accessibility and contribution to glucan masking of natural and genetically tagged versions of yeast wall protein 1 of Candida albicans.

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Bruce L Granger

Full Text Available Yeast wall protein 1 (Ywp1 is an abundant glycoprotein of the cell wall of the yeast form of Candida albicans, the most prevalent fungal pathogen of humans. Antibodies that bind to the polypeptide backbone of isolated Ywp1 show little binding to intact yeast cells, presumably because the Ywp1 epitopes are masked by the polysaccharides of the mannoproteins that form the outer layer of the cell wall. Rare cells do exhibit much greater anti-Ywp1 binding, however, and one of these was isolated and characterized. No differences were seen in its Ywp1, but it exhibited greater adhesiveness, sensitivity to wall perturbing agents, and exposure of its underlying β-1,3-glucan layer to external antibodies. The molecular basis for this greater epitope accessibility has not been determined, but has facilitated exploration of how these properties change as a function of cell growth and morphology. In addition, previously engineered strains with reduced quantities of Ywp1 in their cell walls were also found to have greater β-1,3-glucan exposure, indicating that Ywp1 itself contributes to the masking of wall epitopes, which may be important for understanding the anti-adhesive effect of Ywp1. Ectopic production of Ywp1 by hyphae, which reduces the adhesivity of these filamentous forms of C. albicans, was similarly found to reduce exposure of the β-1,3-glucan in their walls. To monitor Ywp1 in the cell wall irrespective of its accessibility, green fluorescent protein (Gfp was genetically inserted into wall-anchored Ywp1 using a bifunctional cassette that also allowed production from a single transfection of a soluble, anchor-free version. The wall-anchored Ywp1-Gfp-Ywp1 accumulated in the wall of the yeast forms but not hyphae, and appeared to have properties similar to native Ywp1, including its adhesion-inhibiting effect. Some pseudohyphal walls also detectably accumulated this probe. Strains of C. albicans with tandem hemagglutinin (HA epitopes inserted into

Niche-Specific Requirement for Hyphal Wall protein 1 in Virulence of Candida albicans

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Staab, Janet F.; Datta, Kausik; Rhee, Peter

2013-01-01

Specialized Candida albicans cell surface proteins called adhesins mediate binding of the fungus to host cells. The mammalian transglutaminase (TG) substrate and adhesin, Hyphal wall protein 1 (Hwp1), is expressed on the hyphal form of C. albicans where it mediates fungal adhesion to epithelial cells. Hwp1 is also required for biofilm formation and mating thus the protein functions in both fungal-host and self-interactions. Hwp1 is required for full virulence of C. albicans in murine models of disseminated candidiasis and of esophageal candidiasis. Previous studies correlated TG activity on the surface of oral epithelial cells, produced by epithelial TG (TG1), with tight binding of C. albicans via Hwp1 to the host cell surfaces. However, the contribution of other Tgs, specifically tissue TG (TG2), to disseminated candidiasis mediated by Hwp1 was not known. A newly created hwp1 null strain in the wild type SC5314 background was as virulent as the parental strain in C57BL/6 mice, and virulence was retained in C57BL/6 mice deleted for Tgm2 (TG2). Further, the hwp1 null strains displayed modestly reduced virulence in BALB/c mice as did strain DD27-U1, an independently created hwp1Δ/Δ in CAI4 corrected for its ura3Δ defect at the URA3 locus. Hwp1 was still needed to produce wild type biofilms, and persist on murine tongues in an oral model of oropharyngeal candidiasis consistent with previous studies by us and others. Finally, lack of Hwp1 affected the translocation of C. albicans from the mouse intestine into the bloodstream of mice. Together, Hwp1 appears to have a minor role in disseminated candidiasis, independent of tissue TG, but a key function in host- and self-association to the surface of oral mucosa. PMID:24260489

The external face of Candida albicans: A proteomic view of the cell surface and the extracellular environment.

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Gil-Bona, Ana; Amador-García, Ahinara; Gil, Concha; Monteoliva, Lucia

2018-05-30

The cell surface and secreted proteins are the initial points of contact between Candida albicans and the host. Improvements in protein extraction approaches and mass spectrometers have allowed researchers to obtain a comprehensive knowledge of these external subproteomes. In this paper, we review the published proteomic studies that have examined C. albicans extracellular proteins, including the cell surface proteins or surfome and the secreted proteins or secretome. The use of different approaches to isolate cell wall and cell surface proteins, such as fractionation approaches or cell shaving, have resulted in different outcomes. Proteins with N-terminal signal peptide, known as classically secreted proteins, and those that lack the signal peptide, known as unconventionally secreted proteins, have been consistently identified. Existing studies on C. albicans extracellular vesicles reveal that they are relevant as an unconventional pathway of protein secretion and can help explain the presence of proteins without a signal peptide, including some moonlighting proteins, in the cell wall and the extracellular environment. According to the global view presented in this review, cell wall proteins, virulence factors such as adhesins or hydrolytic enzymes, metabolic enzymes and stress related-proteins are important groups of proteins in C. albicans surfome and secretome. Candida albicans extracellular proteins are involved in biofilm formation, cell nutrient acquisition and cell wall integrity maintenance. Furthermore, these proteins include virulence factors and immunogenic proteins. This review is of outstanding interest, not only because it extends knowledge of the C. albicans surface and extracellular proteins that could be related with pathogenesis, but also because it presents insights that may facilitate the future development of new antifungal drugs and vaccines and contributes to efforts to identify new biomarkers that can be employed to diagnose candidiasis

Live Candida albicans Suppresses Production of Reactive Oxygen Species in Phagocytes▿ †

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Wellington, Melanie; Dolan, Kristy; Krysan, Damian J.

2009-01-01

Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-β-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-β-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-β-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-β-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism. PMID:18981256

Cigarette Smoke-Exposed Candida albicans Increased Chitin Production and Modulated Human Fibroblast Cell Responses

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Humidah Alanazi

2014-01-01

Full Text Available The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P<0.01 sensitive to oxidation but significantly (P<0.01 resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P<0.01 slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers.

Candida albicans Hom6 is a homoserine dehydrogenase involved in protein synthesis and cell adhesion

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Pei-Wen Tsai

2017-12-01

Full Text Available Background/Purpose: Candida albicans is a common fungal pathogen in humans. In healthy individuals, C. albicans represents a harmless commensal organism, but infections can be life threatening in immunocompromised patients. The complete genome sequence of C. albicans is extremely useful for identifying genes that may be potential drug targets and important for pathogenic virulence. However, there are still many uncharacterized genes in the Candida genome database. In this study, we investigated C. albicans Hom6, the functions of which remain undetermined experimentally. Methods: HOM6-deleted and HOM6-reintegrated mutant strains were constructed. The mutant strains were compared with wild-type in their growth in various media and enzyme activity. Effects of HOM6 deletion on translation were further investigated by cell susceptibility to hygromycin B or cycloheximide, as well as by polysome profiling, and cell adhesion to polystyrene was also determined. Results: C. albicans Hom6 exhibits homoserine dehydrogenase activity and is involved in the biosynthesis of methionine and threonine. HOM6 deletion caused translational arrest in cells grown under amino acid starvation conditions. Additionally, Hom6 protein was found in both cytosolic and cell-wall fractions of cultured cells. Furthermore, HOM6 deletion reduced C. albicans cell adhesion to polystyrene, which is a common plastic used in many medical devices. Conclusion: Given that there is no Hom6 homologue in mammalian cells, our results provided an important foundation for future development of new antifungal drugs. Keywords: Candida albicans, cell adhesion, Hom6, homoserine dehydrogenase, protein synthesis

The Cek1‑mediated MAP kinase pathway regulates exposure of α‑1,2 and β‑1,2‑mannosides in the cell wall of Candida albicans modulating immune recognition.

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Román, E; Correia, I; Salazin, A; Fradin, C; Jouault, T; Poulain, D; Liu, F-T; Pla, J

2016-07-03

The Cek1 MAP kinase (MAPK) mediates vegetative growth and cell wall biogenesis in the fungal pathogen Candida albicans. Alterations in the fungal cell wall caused by a defective Cek1‑mediated signaling pathway leads to increased β‑1,3‑glucan exposure influencing dectin‑1 fungal recognition by immune cells. We show here that cek1 cells also display an increased exposure of α‑1,2 and β‑1,2‑mannosides (α‑M and β‑M), a phenotype shared by strains defective in the activating MAPKK Hst7, suggesting a general defect in cell wall assembly. cek1 cells display walls with loosely bound material as revealed by transmission electron microscopy and are sensitive to tunicamycin, an inhibitor of N‑glycosylation. Transcriptomal analysis of tunicamycin treated cells revealed a differential pattern between cek1 and wild type cells which involved mainly cell wall and stress related genes. Mapping α‑M and β‑M epitopes in the mannoproteins of different cell wall fractions (CWMP) revealed an important shift in the molecular weight of the mannan derived from mutants defective in this MAPK pathway. We have also assessed the role of galectin‑3, a member of a β‑galactoside‑binding protein family shown to bind to and kill C. albicans through β‑M recognition, in the infection caused by cek1 mutants. Increased binding of cek1 to murine macrophages was shown to be partially blocked by lactose. Galectin-3(-/-) mice showed increased resistance to fungal infection, although galectin-3 did not account for the reduced virulence of cek1 mutants in a mouse model of systemic infection. All these data support a role for the Cek1‑mediated pathway in fungal cell wall maintenance, virulence and antifungal discovery.

Commensal Protection of Staphylococcus aureus against Antimicrobials by Candida albicans Biofilm Matrix

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Kong, Eric F.; Tsui, Christina; Kucharíková, Sona; Andes, David

2016-01-01

ABSTRACT Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections. PMID:27729510

Susceptibility of Candida albicans Isolated from Blood to Wickerhamomyces anomalous Mycocins.

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Paris, Ana Paula; Persel, Cristiane; Serafin, Cleber Fernando; de Cássia Garcia Simão, Rita; Gandra, Rinaldo Ferreira

2016-12-01

The occurrence of infections caused by Candida albicans in developed and developing countries and their resistance to some available antifungal drugs have been viewed as causing a great problem to human health worldwide. In order to find new researched molecules, there are some mycoses secreted by yeasts, especially mycocins produced by Wickerhamomyces anomalus with a broad antimicrobial spectrum of activity. Thus, this trial aimed at evaluating mycocins' activity obtained from environmental W. anomalus cell wall compared to thirty C. albicans strains isolated from blood. Mycocins were extracted from cell walls of three W. anomalus strains (WA40, WA45, and WA92). The 400 μg mL -1 concentration of WA40M1, WA45M2, and WA92M3 mycocin extracts showed the following respective activity results: 96.6, 96.6, and 90.0 % C. albicans strains. WA45M2 and WA92M3 mycocin extracts showed some activity in 3.3 % of C. albicans strains at 50 μg mL -1 concentration. Mycocins extracted from cell walls of three W. anomalus strains named as WA40, WA45, and WA92 showed antifungal activity compared to C. albicans and low degree of hemolysis.

Effect of salivary secretory IgA on the adhesion of Candida albicans to polystyrene.

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San Millán, R; Elguezabal, N; Regúlez, P; Moragues, M D; Quindós, G; Pontón, J

2000-09-01

Attachment of Candida albicans to plastic materials of dental prostheses or to salivary macromolecules adsorbed on their surface is believed to be a critical event in the development of denture stomatitis. In an earlier study, it was shown that adhesion of C. albicans to polystyrene, a model system to study the adhesion of C. albicans to plastic materials, can be partially inhibited with an mAb directed against cell wall polysaccharides of C. albicans. In the present study, the role of whole saliva in the adhesion of C. albicans to polystyrene has been investigated, and three mAbs directed against epitopes of cell wall mannoproteins have been used to mimic the inhibitory effect observed with salivary secretory IgA (sIgA) on the adhesion of C. albicans to polystyrene. In the absence of whole saliva, adherence of C. albicans 3153 increased with germination. However, the presence of whole saliva enhanced the adhesion to polystyrene of C. albicans 3153 yeast cells but decreased the adhesion of germinated cells. The enhancement of adhesion of yeast cells to polystyrene mediated by saliva was confirmed with an agerminative mutant of C. albicans 3153. The inhibition of the adhesion of C. albicans 3153 germ tubes to polystyrene was due to the salivary sIgA since sIgA-depleted saliva enhanced the adhesion of C. albicans 3153 to polystyrene. The inhibitory effect mediated by sIgA was not related to the inhibition of germination but to the blockage of adhesins expressed on the cell wall surface of the germ tubes. The three mAbs studied reduced the adhesion of C. albicans 3153 to polystyrene at levels equivalent to those for purified sIgA. The highest reduction in the adhesion was obtained with the IgA mAb N3B. The best results were obtained when the three mAbs were combined. The results suggest that whole saliva plays a different role in the adhesion of C. albicans to polystyrene depending on the morphological phase of C. albicans. These results may give new insights into the

The Sur7 Protein Regulates Plasma Membrane Organization and Prevents Intracellular Cell Wall Growth in Candida albicans

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Alvarez, Francisco J.; Douglas, Lois M.; Rosebrock, Adam; Konopka, James B.

2008-01-01

The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S. cerevisiae. The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. cerevisiae, a C. albicans sur7Δ mutant displayed defects in endocytosis and morphogenes...

Candida albicans Targets a Lipid Raft/Dectin-1 Platform to Enter Human Monocytes and Induce Antigen Specific T Cell Responses.

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Valeria de Turris

Full Text Available Several pathogens have been described to enter host cells via cholesterol-enriched membrane lipid raft microdomains. We found that disruption of lipid rafts by the cholesterol-extracting agent methyl-β-cyclodextrin or by the cholesterol-binding antifungal drug Amphotericin B strongly impairs the uptake of the fungal pathogen Candida albicans by human monocytes, suggesting a role of raft microdomains in the phagocytosis of the fungus. Time lapse confocal imaging indicated that Dectin-1, the C-type lectin receptor that recognizes Candida albicans cell wall-associated β-glucan, is recruited to lipid rafts upon Candida albicans uptake by monocytes, supporting the notion that lipid rafts act as an entry platform. Interestingly disruption of lipid raft integrity and interference with fungus uptake do not alter cytokine production by monocytes in response to Candida albicans but drastically dampen fungus specific T cell response. In conclusion, these data suggest that monocyte lipid rafts play a crucial role in the innate and adaptive immune responses to Candida albicans in humans and highlight a new and unexpected immunomodulatory function of the antifungal drug Amphotericin B.

Short peptides allowing preferential detection of Candida albicans hyphae.

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Kaba, Hani E J; Pölderl, Antonia; Bilitewski, Ursula

2015-09-01

Whereas the detection of pathogens via recognition of surface structures by specific antibodies and various types of antibody mimics is frequently described, the applicability of short linear peptides as sensor molecules or diagnostic tools is less well-known. We selected peptides which were previously reported to bind to recombinant S. cerevisiae cells, expressing members of the C. albicans Agglutinin-Like-Sequence (ALS) cell wall protein family. We slightly modified amino acid sequences to evaluate peptide sequence properties influencing binding to C. albicans cells. Among the selected peptides, decamer peptides with an "AP"-N-terminus were superior to shorter peptides. The new decamer peptide FBP4 stained viable C. albicans cells more efficiently in their mature hyphal form than in their yeast form. Moreover, it allowed distinction of C. albicans from other related Candida spp. and could thus be the basis for the development of a useful tool for the diagnosis of invasive candidiasis.

Diagnosis of invasive candidiasis by enzyme-linked immunosorbent assay using the N-terminal fragment of Candida albicans hyphal wall protein 1

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Pontón José

2007-04-01

Full Text Available Abstract Background The diagnosis of invasive candidiasis is difficult because there are no specific clinical manifestations of the disease and colonization and infection are difficult to distinguish. In the last decade, much effort has been made to develop reliable tests for rapid diagnosis of invasive candidiasis, but none of them have found widespread clinical use. Results Antibodies against a recombinant N-terminal fragment of the Candida albicans germ tube-specific antigen hyphal wall protein 1 (Hwp1 generated in Escherichia coli were detected by both immunoblotting and ELISA tests in a group of 36 hematological or Intensive Care Unit patients with invasive candidiasis and in a group of 45 control patients at high risk for the mycosis who did not have clinical or microbiological data to document invasive candidiasis. Results were compared with an immunofluorescence test to detect antibodies to C. albicans germ tubes (CAGT. The sensitivity, specificity, positive and negative predictive values of a diagnostic test based on the detection of antibodies against the N-terminal fragment of Hwp1 by immunoblotting were 27.8 %, 95.6 %, 83.3 % and 62.3 %, respectively. Detection of antibodies to the N-terminal fragment of Hwp1 by ELISA increased the sensitivity (88.9 % and the negative predictive value (90.2 % but slightly decreased the specificity (82.6 % and positive predictive values (80 %. The kinetics of antibody response to the N-terminal fragment of Hwp1 by ELISA was very similar to that observed by detecting antibodies to CAGT. Conclusion An ELISA test to detect antibodies against a recombinant N-terminal fragment of the C. albicans germ tube cell wall antigen Hwp1 allows the diagnosis of invasive candidiasis with similar results to those obtained by detecting antibodies to CAGT but without the need of treating the sera to adsorb the antibodies against the cell wall surface of the blastospore.

Candida glabrata Binding to Candida albicans Hyphae Enables Its Development in Oropharyngeal Candidiasis.

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Tati, Swetha; Davidow, Peter; McCall, Andrew; Hwang-Wong, Elizabeth; Rojas, Isolde G; Cormack, Brendan; Edgerton, Mira

2016-03-01

Pathogenic mechanisms of Candida glabrata in oral candidiasis, especially because of its inability to form hyphae, are understudied. Since both Candida albicans and C. glabrata are frequently co-isolated in oropharyngeal candidiasis (OPC), we examined their co-adhesion in vitro and observed adhesion of C. glabrata only to C. albicans hyphae microscopically. Mice were infected sublingually with C. albicans or C. glabrata individually, or with both species concurrently, to study their ability to cause OPC. Infection with C. glabrata alone resulted in negligible infection of tongues; however, colonization by C. glabrata was increased by co-infection or a pre-established infection with C. albicans. Furthermore, C. glabrata required C. albicans for colonization of tongues, since decreasing C. albicans burden with fluconazole also reduced C. glabrata. C. albicans hyphal wall adhesins Als1 and Als3 were important for in vitro adhesion of C. glabrata and to establish OPC. C. glabrata cell wall protein coding genes EPA8, EPA19, AWP2, AWP7, and CAGL0F00181 were implicated in mediating adhesion to C. albicans hyphae and remarkably, their expression was induced by incubation with germinated C. albicans. Thus, we found a near essential requirement for the presence of C. albicans for both initial colonization and establishment of OPC infection by C. glabrata.

Evaluation of Antifungal Activity and Mechanism of Action of Citral against Candida albicans

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Maria Clerya Alvino Leite

2014-01-01

Full Text Available Candida albicans is a yeast that commensally inhabits the human body and can cause opportunistic or pathogenic infections. Objective. To investigate the antifungal activity of citral against C. albicans. Methodology. The minimum inhibitory concentration (MIC and the minimum fungicidal concentration (MFC were determined by the broth microdilution techniques. We also investigated possible citral action on cell walls (0.8 M sorbitol, cell membranes (citral to ergosterol binding, the time-kill curve, and biological activity on the yeast’s morphology. Results. The MIC and MFC of citral were, respectively, 64 µg/mL and 256 µg/mL. Involvement with the cell wall and ergosterol binding were excluded as possible mechanisms of action. In the morphological interference assay, it was observed that the product inhibited pseudohyphae and chlamydoconidia formation. The MIC and the MFC of citral required only 4 hours of exposure to effectively kill 99.9% of the inoculum. Conclusion. Citral showed in vitro antifungal potential against strains of C. albicans. Citral’s mechanism of action does not involve the cell wall or ergosterol, and further study is needed to completely describe its effects before being used in the future as a component of new antifungals.

Anti-Candida albicans biofilm effect of novel heterocyclic compounds.

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Kagan, Sarah; Jabbour, Adel; Sionov, Edward; Alquntar, Abed A; Steinberg, Doron; Srebnik, Morris; Nir-Paz, Ran; Weiss, Aryeh; Polacheck, Itzhack

2014-02-01

The aims of this study were to develop new anti-biofilm drugs, examine their activity against Candida albicans biofilm and investigate their structure-activity relationship and mechanism of action. A series of thiazolidinedione and succinimide derivatives were synthesized and their ability to inhibit C. albicans biofilm formation and destroy pre-formed biofilm was tested. The biofilms' structure, metabolic activity and viability were determined by XTT assay and propidium iodide and SYTO 9 live/dead stains combined with confocal microscopic analysis. The effect of the most active compounds on cell morphology, sterol distribution and cell wall morphology and composition was then determined by specific fluorescent stains and transmission electron microscopy. Most of the compounds were active at sub-MICs. Elongation of the aliphatic side chain resulted in reduced anti-biofilm activity and the sulphur atom contributed to biofilm killing, indicating a structure-activity relationship. The compounds differed in their effects on biofilm viability, yeast-to-hyphal form transition, hyphal morphology, cell wall morphology and composition, and sterol distribution. The most effective anti-biofilm compounds were the thiazolidinedione S8H and the succinimide NA8. We developed novel anti-biofilm agents that both inhibited and destroyed C. albicans biofilm. With some further development, these agents might be suitable for therapeutic purposes.

Exposure to Candida albicans polarizes a T-cell driven arthritis model towards Th17 responses, resulting in a more destructive arthritis.

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Marijnissen, Renoud J; Koenders, Marije I; van de Veerdonk, Frank L; Dulos, John; Netea, Mihai G; Boots, Annemieke M H; Joosten, Leo A B; van den Berg, Wim B

2012-01-01

Fungal components have been shown very effective in generating Th17 responses. We investigated whether exposure to a minute amount of C. albicans in the arthritic joint altered the local cytokine environment, leading to enhanced Th17 expansion and resulting in a more destructive arthritis. Chronic SCW arthritis was induced by repeated injection with Streptococcus pyogenes (SCW) cell wall fragments into the knee joint of C57Bl/6 mice, alone or in combination with the yeast of C. albicans or Zymosan A. During the chronic phase of the arthritis, the cytokine levels, mRNA expression and histopathological analysis of the joints were performed. To investigate the phenotype of the IL-17 producing T-cells, synovial cells were isolated and analyzed by flowcytometry. Intra-articular injection of either Zymosan A or C. albicans on top of the SCW injection both resulted in enhanced joint swelling and inflammation compared to the normal SCW group. However, only the addition of C. albicans during SCW arthritis resulted in severe chondrocyte death and enhanced destruction of cartilage and bone. Additionally, exposure to C. albicans led to increased IL-17 in the arthritic joint, which was accompanied by an increased synovial mRNA expression of T-bet and RORγT. Moreover, the C. albicans-injected mice had significantly more Th17 cells in the synovium, of which a large population also produced IFN-γ. This study clearly shows that minute amounts of fungal components, like C. albicans, are very potent in interfering with the local cytokine environment in an arthritic joint, thereby polarizing arthritis towards a more destructive phenotype.

Extracellular Vesicle-Associated Transitory Cell Wall Components and Their Impact on the Interaction of Fungi with Host Cells.

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Nimrichter, Leonardo; de Souza, Marcio M; Del Poeta, Maurizio; Nosanchuk, Joshua D; Joffe, Luna; Tavares, Patricia de M; Rodrigues, Marcio L

2016-01-01

Classic cell wall components of fungi comprise the polysaccharides glucans and chitin, in association with glycoproteins and pigments. During the last decade, however, system biology approaches clearly demonstrated that the composition of fungal cell walls include atypical molecules historically associated with intracellular or membrane locations. Elucidation of mechanisms by which many fungal molecules are exported to the extracellular space suggested that these atypical components are transitorily located to the cell wall. The presence of extracellular vesicles (EVs) at the fungal cell wall and in culture supernatants of distinct pathogenic species suggested a highly functional mechanism of molecular export in these organisms. Thus, the passage of EVs through fungal cell walls suggests remarkable molecular diversity and, consequently, a potentially variable influence on the host antifungal response. On the basis of information derived from the proteomic characterization of fungal EVs from the yeasts Cryptoccocus neoformans and Candida albicans and the dimorphic fungi Histoplasma capsulatum and Paracoccidioides brasiliensis, our manuscript is focused on the clear view that the fungal cell wall is much more complex than previously thought.

Limonene inhibits Candida albicans growth by inducing apoptosis.

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Thakre, Archana; Zore, Gajanan; Kodgire, Santosh; Kazi, Rubina; Mulange, Shradha; Patil, Rajendra; Shelar, Amruta; Santhakumari, Bayitigeri; Kulkarni, Mahesh; Kharat, Kiran; Karuppayil, Sankunny Mohan

2018-07-01

Anti-Candida potential of limonene was evaluated against planktonic growth, biofilm (adhesion, development and maturation) and morphogenesis of Candida albicans in this study. Limonene is a major constituent of citrus oil and most frequently used terpene in food and beverage industry due to its pleasant fragrance, nontoxic, and is generally recognized as safe (GRAS) flavoring agent as well as treatment option in many gastrointestinal diseases.Limonene exhibited excellent anti-Candida activity and was equally effective against planktonic growth of C. albicans isolates differentially susceptible to FLC (N = 35). Limonene inhibited morphogenesis significantly at low concentration. However, it showed stage dependent activity against biofilm formation, that is, it was more effective against adhesion followed by development and maturation. Limonene also exhibited excellent synergy with FLC against planktonic and biofilm growth. SWATH-MS analysis led to identification of limonene responsive proteins that provided molecular insight of its anti-Candida activity. Proteomic analysis revealed upregulation of proteins involved in cell wall glucan synthesis (Kre6); oxidative stress (Rhr2, Adh7 and Ebp1); DNA damage stress (Mbf1 and Npl3); nucleolar stress (Rpl11, Rpl7, Rpl29, Rpl15) and down regulation of cytoskeleton organization (Crn1, Pin3, Cct8, Rbl2), and so forth, in response to limonene. Limonene mediated down regulation of Tps3 indicates activation of caspase (CaMca1) and induction of apoptosis in C. albicans. These results suggest that limonene inhibits C. albicans growth by cell wall/membrane damage induced oxidative stress that leads to DNA damage resulting into modulation of cell cycle and induction of apoptosis through nucleolar stress and metacaspase dependent pathway.

Global Transcriptome Sequencing Identifies Chlamydospore Specific Markers in Candida albicans and Candida dubliniensis

LENUS (Irish Health Repository)

Palige, Katja

2013-04-15

Candida albicans and Candida dubliniensis are pathogenic fungi that are highly related but differ in virulence and in some phenotypic traits. During in vitro growth on certain nutrient-poor media, C. albicans and C. dubliniensis are the only yeast species which are able to produce chlamydospores, large thick-walled cells of unknown function. Interestingly, only C. dubliniensis forms pseudohyphae with abundant chlamydospores when grown on Staib medium, while C. albicans grows exclusively as a budding yeast. In order to further our understanding of chlamydospore development and assembly, we compared the global transcriptional profile of both species during growth in liquid Staib medium by RNA sequencing. We also included a C. albicans mutant in our study which lacks the morphogenetic transcriptional repressor Nrg1. This strain, which is characterized by its constitutive pseudohyphal growth, specifically produces masses of chlamydospores in Staib medium, similar to C. dubliniensis. This comparative approach identified a set of putatively chlamydospore-related genes. Two of the homologous C. albicans and C. dubliniensis genes (CSP1 and CSP2) which were most strongly upregulated during chlamydospore development were analysed in more detail. By use of the green fluorescent protein as a reporter, the encoded putative cell wall related proteins were found to exclusively localize to C. albicans and C. dubliniensis chlamydospores. Our findings uncover the first chlamydospore specific markers in Candida species and provide novel insights in the complex morphogenetic development of these important fungal pathogens.

Disruption of Protein Mannosylation Affects Candida guilliermondii Cell Wall, Immune Sensing, and Virulence

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María J. Navarro-Arias

2016-12-01

Full Text Available The fungal cell wall contains glycoproteins that interact with the host immune system. In the prominent pathogenic yeast Candida albicans, Pmr1 acts as a Golgi-resident ion pump that provides cofactors to mannosyltransferases, regulating the synthesis of mannans attached to glycoproteins. To gain insight into a putative conservation of such a crucial process within opportunistic yeasts, we were particularly interested in studying the role of the PMR1 homolog in a low-virulent species that rarely causes candidiasis, Candida guilliermondii. We disrupted C. guilliermondii PMR1 and found that loss of Pmr1 affected cell growth and morphology, biofilm formation, susceptibility to cell wall perturbing agents, mannan levels, and the wall composition and organization. Despite there was a significant increment in the amount of β1,3-glucan exposed at the wall surface, this positively influenced only the ability of the mutant to stimulate IL-10 production by human monocytes, suggesting that recognition of both mannan and β1,3-glucan, is required to stimulate strong levels of pro-inflammatory cytokines. Accordingly, our results indicate C. guilliermondii sensing by monocytes was critically dependent on the recognition of N-linked mannans and β1,3-glucan, as reported in other Candida species. In addition, chemical remotion of cell wall O-linked mannans was found to positively influence the recognition of C. guilliermondii by human monocytes, suggesting that O-linked mannans mask other cell wall components from immune cells. This observation contrasts with that reported in C. albicans. Finally, mice infected with C. guilliermondii pmr1 null mutant cells had significantly lower fungal burdens compared to animals challenged with the parental strain. Accordingly, the null mutant showed inability to kill larvae in the Galleria mellonella infection model. This study thus demonstrates that mannans are relevant for the C. guilliermondii-host interaction, with

Macrophage Reporter Cell Assay for Screening Immunopharmacological Activity of Cell Wall-Active Antifungals

OpenAIRE

Lewis, Russell E.; Liao, Guangling; Young, Katherine; Douglas, Cameron; Kontoyiannis, Dimitrios P.

2014-01-01

Antifungal exposure can elicit immunological effects that contribute to activity in vivo, but this activity is rarely screened in vitro in a fashion analogous to MIC testing. We used RAW 264.7 murine macrophages that express a secreted embryonic alkaline phosphatase (SEAP) gene induced by transcriptional activation of NF-κB and activator protein 1 (AP-1) to develop a screen for immunopharmacological activity of cell wall-active antifungal agents. Isolates of Candida albicans and Aspergillus f...

Psd1 Effects on Candida albicans Planktonic Cells and Biofilms

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Sónia Gonçalves

2017-06-01

Full Text Available Candida albicans is an important human pathogen, causing opportunistic infections. The adhesion of planktonic cells to a substrate is the first step for biofilm development. The antimicrobial peptide (AMP Psd1 is a defensin isolated from Pisum sativum seeds. We tested the effects of this AMP on C. albicans biofilms and planktonic cells, comparing its activity with amphotericin B and fluconazole. Three C. albicans variants were studied, one of them a mutant deficient in glucosylceramide synthase, conferring resistance to Psd1 antifungal action. Atomic force microscopy (AFM was used to assess morphological and biomechanical changes on fungal cells. Surface alterations, with membrane disruption and leakage of cellular contents, were observed. Cytometry assays and confocal microscopy imaging showed that Psd1 causes cell death, in a time and concentration-dependent manner. These results demonstrate Psd1 pleiotropic action against a relevant fungal human pathogen, suggesting its use as natural antimycotic agent.

A multifunctional mannosyltransferase family in Candida albicans determines cell wall mannan structure and host-fungus interactions.

NARCIS (Netherlands)

Mora-Montes, H.M.; Bates, S.; Netea, M.G.; Castillo, L.; Brand, A.; Buurman, E.T.; Diaz-Jimenez, D.F.; Kullberg, B.J.; Brown, A.J.; Odds, F.C.; Gow, N.A.

2010-01-01

The cell wall proteins of fungi are modified by N- and O-linked mannosylation and phosphomannosylation, resulting in changes to the physical and immunological properties of the cell. Glycosylation of cell wall proteins involves the activities of families of endoplasmic reticulum and Golgi-located

Novel structural features in Candida albicans hyphal glucan provide a basis for differential innate immune recognition of hyphae versus yeast.

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Lowman, Douglas W; Greene, Rachel R; Bearden, Daniel W; Kruppa, Michael D; Pottier, Max; Monteiro, Mario A; Soldatov, Dmitriy V; Ensley, Harry E; Cheng, Shih-Chin; Netea, Mihai G; Williams, David L

2014-02-07

The innate immune system differentially recognizes Candida albicans yeast and hyphae. It is not clear how the innate immune system effectively discriminates between yeast and hyphal forms of C. albicans. Glucans are major components of the fungal cell wall and key fungal pathogen-associated molecular patterns. C. albicans yeast glucan has been characterized; however, little is known about glucan structure in C. albicans hyphae. Using an extraction procedure that minimizes degradation of the native structure, we extracted glucans from C. albicans hyphal cell walls. (1)H NMR data analysis revealed that, when compared with reference (1→3,1→6) β-linked glucans and C. albicans yeast glucan, hyphal glucan has a unique cyclical or "closed chain" structure that is not found in yeast glucan. GC/MS analyses showed a high abundance of 3- and 6-linked glucose units when compared with yeast β-glucan. In addition to the expected (1→3), (1→6), and 3,6 linkages, we also identified a 2,3 linkage that has not been reported previously in C. albicans. Hyphal glucan induced robust immune responses in human peripheral blood mononuclear cells and macrophages via a Dectin-1-dependent mechanism. In contrast, C. albicans yeast glucan was a much less potent stimulus. We also demonstrated the capacity of C. albicans hyphal glucan, but not yeast glucan, to induce IL-1β processing and secretion. This finding provides important evidence for understanding the immune discrimination between colonization and invasion at the mucosal level. When taken together, these data provide a structural basis for differential innate immune recognition of C. albicans yeast versus hyphae.

Spaceflight enhances cell aggregation and random budding in Candida albicans.

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Aurélie Crabbé

Full Text Available This study presents the first global transcriptional profiling and phenotypic characterization of the major human opportunistic fungal pathogen, Candida albicans, grown in spaceflight conditions. Microarray analysis revealed that C. albicans subjected to short-term spaceflight culture differentially regulated 452 genes compared to synchronous ground controls, which represented 8.3% of the analyzed ORFs. Spaceflight-cultured C. albicans-induced genes involved in cell aggregation (similar to flocculation, which was validated by microscopic and flow cytometry analysis. We also observed enhanced random budding of spaceflight-cultured cells as opposed to bipolar budding patterns for ground samples, in accordance with the gene expression data. Furthermore, genes involved in antifungal agent and stress resistance were differentially regulated in spaceflight, including induction of ABC transporters and members of the major facilitator family, downregulation of ergosterol-encoding genes, and upregulation of genes involved in oxidative stress resistance. Finally, downregulation of genes involved in actin cytoskeleton was observed. Interestingly, the transcriptional regulator Cap1 and over 30% of the Cap1 regulon was differentially expressed in spaceflight-cultured C. albicans. A potential role for Cap1 in the spaceflight response of C. albicans is suggested, as this regulator is involved in random budding, cell aggregation, and oxidative stress resistance; all related to observed spaceflight-associated changes of C. albicans. While culture of C. albicans in microgravity potentiates a global change in gene expression that could induce a virulence-related phenotype, no increased virulence in a murine intraperitoneal (i.p. infection model was observed under the conditions of this study. Collectively, our data represent an important basis for the assessment of the risk that commensal flora could play during human spaceflight missions. Furthermore, since the

Selection of aptamers for Candida albicans by cell-SELEX; Selecao de aptameros para Candida albicans por cell-SELEX

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Miranda, Alessandra Nunes Duarte

2017-07-01

The growing concern with invasive fungal infections, responsible for an alarming mortality rate of immunosuppressed patients and in Intensive Care Units, evidences the need for a fast and specific method for the Candida albicans detection, since this species is identified as one of the main causes of septicemia. Commonly, it is a challenge for clinicians to determine the primary infection foci, the dissemination degree, or whether the site of a particular surgery is involved. Although scintigraphic imaging represents a promising tool for infectious foci detection, it still lacks a methodology for C. albicans diagnosis due to the absence of specific radiotracers for this microorganism. Aptamers are molecules that have almost ideal properties for use as diagnostic radiopharmaceuticals, such as high specificity for their molecular targets, lack of immunogenicity and toxicity, high tissue penetration and rapid blood clearance. Aptamers can also be labeled with different radionuclides. This work aims to obtain aptamers for specific binding to C. albicans cells for future application as a radiopharmaceutical. It was used a variation of the SELEX (Systematic Evolution of Ligands by EXponential Enrichment) technique, termed cell-SELEX, in which cells are the targets for selection. A selection protocol was standardized using a random library of single-stranded oligonucleotides, each containing two fixed regions flanking a sequence of 40 random nucleotides. This library was incubated with C. albicans cells in the presence of competitors. Then, the binding sequences were separated by centrifugation, resuspended and amplified by PCR. The amplification was confirmed by agarose gel electrophoresis. After that, the ligands were purified to obtain a new pool of ssDNA, from which a new incubation was carried out. The selection parameters were gradually modified in order to increase stringency. This cycle was repeated 12 times to allow the selection of sequences with the maximum

Hsp90 orchestrates transcriptional regulation by Hsf1 and cell wall remodelling by MAPK signalling during thermal adaptation in a pathogenic yeast.

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Michelle D Leach

2012-12-01

Full Text Available Thermal adaptation is essential in all organisms. In yeasts, the heat shock response is commanded by the heat shock transcription factor Hsf1. Here we have integrated unbiased genetic screens with directed molecular dissection to demonstrate that multiple signalling cascades contribute to thermal adaptation in the pathogenic yeast Candida albicans. We show that the molecular chaperone heat shock protein 90 (Hsp90 interacts with and down-regulates Hsf1 thereby modulating short term thermal adaptation. In the longer term, thermal adaptation depends on key MAP kinase signalling pathways that are associated with cell wall remodelling: the Hog1, Mkc1 and Cek1 pathways. We demonstrate that these pathways are differentially activated and display cross talk during heat shock. As a result ambient temperature significantly affects the resistance of C. albicans cells to cell wall stresses (Calcofluor White and Congo Red, but not osmotic stress (NaCl. We also show that the inactivation of MAP kinase signalling disrupts this cross talk between thermal and cell wall adaptation. Critically, Hsp90 coordinates this cross talk. Genetic and pharmacological inhibition of Hsp90 disrupts the Hsf1-Hsp90 regulatory circuit thereby disturbing HSP gene regulation and reducing the resistance of C. albicans to proteotoxic stresses. Hsp90 depletion also affects cell wall biogenesis by impairing the activation of its client proteins Mkc1 and Hog1, as well as Cek1, which we implicate as a new Hsp90 client in this study. Therefore Hsp90 modulates the short term Hsf1-mediated activation of the classic heat shock response, coordinating this response with long term thermal adaptation via Mkc1- Hog1- and Cek1-mediated cell wall remodelling.

The determination of optimal cells disintegration method of Candida albicans and Candida tropicalis fungals

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M. V. Rybalkyn

2014-08-01

Full Text Available Candidiasis is common infectious disease that affects the mucous membranes, skin, nails, hair, and internal organs. Now Ukraine has neither domestic nor registered imported vaccine against candidiasis. The development of vaccine for prevention and treatment of candidiasis is a key issue in modern medicine and pharmacy. Similar research is actively conducted in many countries of the world: Russia, USA, Japan and others. It should be noted that researchers have not yet reached a consensus view which vaccine is most effective with candidiasis. There are several types of vaccines: live, inactivated, subunit and others. In this article, we consider getting the potential subunit vaccine from Candida albicans and Candida tropicalis fungi. Subunit vaccine is composed of fragments of antigens that can provide an adequate immune response. These vaccines can be represented by particles of microbes. It is known that the main substances in cells of genus Candida fungi, which have antigenic properties, are proteins and polysaccharides. However, the question of their localization in the layers of the cell wall and cytoplasm nowadays require more detailed studies. Many researchers to highlight cytoplasm antigens and all the other layers of the cell use the following methods: grinding cells with quartz sand, destroying them in different machine disintegrating, freezing and thawing a multi others. To obtain potential subunit vaccine fungi were rejected by methods that are based on the processing of biomass fungi chemicals (extraction, hydrolysis. The aim of this work was to study experimentally the destruction method of Candida albicans and Candida tropicalis fungi. Cells of Candida albicans fungi strain CCM 335-867 and Candida tropicalis fungi strain 20336 ATTS have been separately cultured in vitro on agar Sabouraud at 25 ± 2º C for 48 hours and then washed by 10 ml of sterile 0.9% isotonic sodium chloride solution. Cell suspension of Candida albicans and

Mnn10 Maintains Pathogenicity in Candida albicans by Extending α-1,6-Mannose Backbone to Evade Host Dectin-1 Mediated Antifungal Immunity.

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Shi Qun Zhang

2016-05-01

Full Text Available The cell wall is a dynamic structure that is important for the pathogenicity of Candida albicans. Mannan, which is located in the outermost layer of the cell wall, has been shown to contribute to the pathogenesis of C. albicans, however, the molecular mechanism by which this occurs remains unclear. Here we identified a novel α-1,6-mannosyltransferase encoded by MNN10 in C. albicans. We found that Mnn10 is required for cell wall α-1,6-mannose backbone biosynthesis and polysaccharides organization. Deletion of MNN10 resulted in significant attenuation of the pathogenesis of C. albicans in a murine systemic candidiasis model. Inhibition of α-1,6-mannose backbone extension did not, however, impact the invasive ability of C. albicans in vitro. Notably, mnn10 mutant restored the invasive capacity in athymic nude mice, which further supports the notion of an enhanced host antifungal defense related to this backbone change. Mnn10 mutant induced enhanced Th1 and Th17 cell mediated antifungal immunity, and resulted in enhanced recruitment of neutrophils and monocytes for pathogen clearance in vivo. We also demonstrated that MNN10 could unmask the surface β-(1,3-glucan, a crucial pathogen-associated molecular pattern (PAMP of C. albicans recognized by host Dectin-1. Our results demonstrate that mnn10 mutant could stimulate an enhanced Dectin-1 dependent immune response of macrophages in vitro, including the activation of nuclear factor-κB, mitogen-activated protein kinase pathways, and secretion of specific cytokines such as TNF-α, IL-6, IL-1β and IL-12p40. In summary, our study indicated that α-1,6-mannose backbone is critical for the pathogenesis of C. albicans via shielding β-glucan from recognition by host Dectin-1 mediated immune recognition. Moreover, our work suggests that inhibition of α-1,6-mannose extension by Mnn10 may represent a novel modality to reduce the pathogenicity of C. albicans.

Modulation of intestinal inflammation by yeasts and cell wall extracts: strain dependence and unexpected anti-inflammatory role of glucan fractions.

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Samir Jawhara

Full Text Available Yeasts and their glycan components can have a beneficial or adverse effect on intestinal inflammation. Previous research has shown that the presence of Saccharomyces cerevisiae var. boulardii (Sb reduces intestinal inflammation and colonization by Candida albicans. The aim of this study was to identify dietary yeasts, which have comparable effects to the anti-C. albicans and anti-inflammatory properties of Sb and to assess the capabilities of yeast cell wall components to modulate intestinal inflammation. Mice received a single oral challenge of C. albicans and were then given 1.5% dextran-sulphate-sodium (DSS for 2 weeks followed by a 3-day restitution period. S. cerevisiae strains (Sb, Sc1 to Sc4, as well as mannoprotein (MP and β-glucan crude fractions prepared from Sc2 and highly purified β-glucans prepared from C. albicans were used in this curative model, starting 3 days after C. albicans challenge. Mice were assessed for the clinical, histological and inflammatory responses related to DSS administration. Strain Sc1-1 gave the same level of protection against C. albicans as Sb when assessed by mortality, clinical scores, colonization levels, reduction of TNFα and increase in IL-10 transcription. When Sc1-1 was compared with the other S. cerevisiae strains, the preparation process had a strong influence on biological activity. Interestingly, some S. cerevisiae strains dramatically increased mortality and clinical scores. Strain Sc4 and MP fraction favoured C. albicans colonization and inflammation, whereas β-glucan fraction was protective against both. Surprisingly, purified β-glucans from C. albicans had the same protective effect. Thus, some yeasts appear to be strong modulators of intestinal inflammation. These effects are dependent on the strain, species, preparation process and cell wall fraction. It was striking that β-glucan fractions or pure β-glucans from C. albicans displayed the most potent anti-inflammatory effect in the

Miltefosine inhibits Candida albicans and non-albicans Candida spp. biofilms and impairs the dispersion of infectious cells.

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Vila, Taissa; Ishida, Kelly; Seabra, Sergio Henrique; Rozental, Sonia

2016-11-01

Candida spp. can adhere to and form biofilms over different surfaces, becoming less susceptible to antifungal treatment. Resistance of biofilms to antifungal agents is multifactorial and the extracellular matrix (ECM) appears to play an important role. Among the few available antifungals for treatment of candidaemia, only the lipid formulations of amphotericin B (AmB) and the echinocandins are effective against biofilms. Our group has previously demonstrated that miltefosine has an important effect against Candida albicans biofilms. Thus, the aim of this work was to expand the analyses of the in vitro antibiofilm activity of miltefosine to non-albicans Candida spp. Miltefosine had significant antifungal activity against planktonic cells and the development of biofilms of C. albicans, Candida parapsilosis, Candida tropicalis and Candida glabrata. The activity profile in biofilms was superior to fluconazole and was similar to that of AmB and caspofungin. Biofilm-derived cells with their ECM extracted became as susceptible to miltefosine as planktonic cells, confirming the importance of the ECM in the biofilm resistant behaviour. Miltefosine also inhibited biofilm dispersion of cells at the same concentration needed to inhibit planktonic cell growth. The data obtained in this work reinforce the potent inhibitory activity of miltefosine on biofilms of the four most pathogenic Candida spp. and encourage further studies for the utilisation of this drug and/or structural analogues on biofilm-related infections. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies.

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Faria, Daniella Renata; Sakita, Karina Mayumi; Akimoto-Gunther, Luciene Setsuko; Kioshima, Érika Seki; Svidzinski, Terezinha Inez Estivalet; Bonfim-Mendonça, Patrícia de Souza

2017-08-01

The present study aimed to characterize cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies. It was evaluated 12 clinical isolates of C. albicans from vaginal samples: 4 from asymptomatic women (AS), 4 from women with a single episode of vulvovaginal candidiasis (VVC) and 4 from women with recurrent vulvovaginal candidiasis (RVVC). We evaluated the ability of C. albicans to adhere to human cervical cancer cells (SiHa), the yeast-SiHa cell interactions and cell damage. All of the clinical isolates presented a high adhesion capacity on SiHa cells. However, clinical isolates from symptomatic women (VVC and RVVC) had higher filamentation after contact (24 h) with SiHa cells and a greater capacity to cause cell damage (>80 %). Clinical isolates from symptomatic women had greater potential to invade SiHa cells, suggesting that they are more pathogenic than AS isolates.

Functional Genomic Screening Reveals Core Modulators of Echinocandin Stress Responses in Candida albicans

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Tavia Caplan

2018-05-01

Full Text Available Summary: Candida albicans is a leading cause of death due to fungal infection. Treatment of systemic candidiasis often relies on echinocandins, which disrupt cell wall synthesis. Resistance is readily acquired via mutations in the drug target gene, FKS1. Both basal tolerance and resistance to echinocandins require cellular stress responses. We performed a systematic analysis of 3,030 C. albicans mutants to define circuitry governing cellular responses to echinocandins. We identified 16 genes for which deletion or transcriptional repression enhanced echinocandin susceptibility, including components of the Pkc1-MAPK signaling cascade. We discovered that the molecular chaperone Hsp90 is required for the stability of Pkc1 and Bck1, establishing key mechanisms through which Hsp90 mediates echinocandin resistance. We also discovered that perturbation of the CCT chaperonin complex causes enhanced echinocandin sensitivity, altered cell wall architecture, and aberrant septin localization. Thus, we provide insights into the mechanisms by which cellular chaperones enable crucial responses to echinocandin-induced stress. : Caplan et al. screen 3,030 Candida albicans mutants to define circuitry governing cellular responses to echinocandins, the first-line therapy for systemic candidiasis. They reveal that the molecular chaperone Hsp90 is required for stability of Pkc1 and Bck1 and that the CCT chaperonin complex is a key modulator of echinocandin susceptibility. Keywords: fungal pathogen, Candida albicans, echinocandins, Hsp90, Pkc1, CCT complex, client protein, stress response, functional genomic screen, drug resistance

Horizontal transmission of Candida albicans and evidence of a vaccine response in mice colonized with the fungus.

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Cutler, Jim E; Corti, Miriam; Lambert, Patrick; Ferris, Michael; Xin, Hong

2011-01-01

Disseminated candidiasis is the third leading nosocomial blood stream infection in the United States and is often fatal. We previously showed that disseminated candidiasis was preventable in normal mice by immunization with either a glycopeptide or a peptide synthetic vaccine, both of which were Candida albicans cell wall derived. A weakness of these studies is that, unlike humans, mice do not have a C. albicans GI flora and they lack Candida serum antibodies. We examined the influence of C. albicans GI tract colonization and serum antibodies on mouse vaccination responses to the peptide, Fba, derived from fructose bisphosphate aldolase which has cytosolic and cell wall distributions in the fungus. We evaluated the effect of live C. albicans in drinking water and antimicrobial agents on establishment of Candida colonization of the mouse GI tract. Body mass, C. albicans in feces, and fungal-specific serum antibodies were monitored longitudinally. Unexpectedly, C. albicans colonization occurred in mice that received only antibiotics in their drinking water, provided that the mice were housed in the same room as intentionally colonized mice. The fungal strain in unintentionally colonized mice appeared identical to the strain used for intentional GI-tract colonization. This is the first report of horizontal transmission and spontaneous C. albicans colonization in mice. Importantly, many Candida-colonized mice developed serum fungal-specific antibodies. Despite the GI-tract colonization and presence of serum antibodies, the animals made antibodies in response to the Fba immunogen. This mouse model has potential for elucidating C. albicans horizontal transmission and for exploring factors that induce host defense against disseminated candidiasis. Furthermore, a combined protracted GI-tract colonization with Candida and the possibility of serum antibody responses to the presence of the fungus makes this an attractive mouse model for testing the efficacy of vaccines

Horizontal transmission of Candida albicans and evidence of a vaccine response in mice colonized with the fungus.

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Jim E Cutler

Full Text Available Disseminated candidiasis is the third leading nosocomial blood stream infection in the United States and is often fatal. We previously showed that disseminated candidiasis was preventable in normal mice by immunization with either a glycopeptide or a peptide synthetic vaccine, both of which were Candida albicans cell wall derived. A weakness of these studies is that, unlike humans, mice do not have a C. albicans GI flora and they lack Candida serum antibodies. We examined the influence of C. albicans GI tract colonization and serum antibodies on mouse vaccination responses to the peptide, Fba, derived from fructose bisphosphate aldolase which has cytosolic and cell wall distributions in the fungus. We evaluated the effect of live C. albicans in drinking water and antimicrobial agents on establishment of Candida colonization of the mouse GI tract. Body mass, C. albicans in feces, and fungal-specific serum antibodies were monitored longitudinally. Unexpectedly, C. albicans colonization occurred in mice that received only antibiotics in their drinking water, provided that the mice were housed in the same room as intentionally colonized mice. The fungal strain in unintentionally colonized mice appeared identical to the strain used for intentional GI-tract colonization. This is the first report of horizontal transmission and spontaneous C. albicans colonization in mice. Importantly, many Candida-colonized mice developed serum fungal-specific antibodies. Despite the GI-tract colonization and presence of serum antibodies, the animals made antibodies in response to the Fba immunogen. This mouse model has potential for elucidating C. albicans horizontal transmission and for exploring factors that induce host defense against disseminated candidiasis. Furthermore, a combined protracted GI-tract colonization with Candida and the possibility of serum antibody responses to the presence of the fungus makes this an attractive mouse model for testing the

Characteristics of DTH suppressor cells in mice infected with Candida albicans.

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Valdez, J C; Mesón, O E; Sirena, A; de Alderete, N G

1987-05-01

Inoculation of 10(8) C. albicans intraperitoneally into Balb/c mice at given dosage was reported to induce suppression of antigen-specific delayed-type hypersensitivity. Adoptive transfer of spleen cells into normal syngeneic mice pre-treated with Cyclophosphamide confirmed the existence of suppressor cells in mice. Such cells were sensitive to treatment with anti-theta serum and complement, non-adherent to Sephadex G-10. A pretreatment of the mice with Cyclophosphamide eliminated DTH suppression. Treatment with antimacrophage agents via intraperitoneal abrogated suppression only if being effected before inoculation of alive 10(8) Candida albicans. It is concluded that the spleen suppressor cell is a T-lymphocyte whose precursor is Cyclophosphamide-sensitive, requiring the macrophage to be induced.

Distribution of Candida albicans and non-albicans Candida species in oral candidiasis patients: Correlation between cell surface hydrophobicity and biofilm forming activities.

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Muadcheingka, Thaniya; Tantivitayakul, Pornpen

2015-06-01

The purposes of this investigation were to study the prevalence of Candida albicans and non-albicans Candida (NAC) species from oral candidiasis patients and evaluate the cell surface hydrophobicity (CSH) and biofilm forming capacity of the clinical isolates Candida species from oral cavity. This study identified a total of 250 Candida strains isolated from 207 oral candidiasis patients with PCR-RFLP technique. CSH value, total biomass of biofilm and biofilm forming ability of 117 oral Candida isolates were evaluated. C. albicans (61.6%) was still the predominant species in oral candidiasis patients with and without denture wearer, respectively, followed by C. glabrata (15.2%), C. tropicalis (10.4%), C. parapsilosis (3.2%), C. kefyr (3.6%), C. dubliniensis (2%), C. lusitaniae (2%), C. krusei (1.6%), and C. guilliermondii (0.4%). The proportion of mixed colonization with more than one Candida species was 18% from total cases. The relative CSH value and biofilm biomass of NAC species were greater than C. albicans (poral isolates NAC species had biofilm forming ability, whereas 78% of C. albicans were biofilm formers. Furthermore, the significant difference of relative CSH values between biofilm formers and non-biofilm formers was observed in the NAC species (poral cavity was gradually increasing. The possible contributing factors might be high cell surface hydrophobicity and biofilm forming ability. The relative CSH value could be a putative factor for determining biofilm formation ability of the non-albicans Candida species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthetic arylquinuclidine derivatives exhibit antifungal activity against Candida albicans, Candida tropicalis and Candida parapsilopsis

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Gilbert Ian

2011-01-01

Full Text Available Abstract Background Sterol biosynthesis is an essential pathway for fungal survival, and is the biochemical target of many antifungal agents. The antifungal drugs most widely used to treated fungal infections are compounds that inhibit cytochrome P450-dependent C14α-demethylase (CYP51, but other enzymes of this pathway, such as squalene synthase (SQS which catalyses the first committed step in sterol biosynthesis, could be viable targets. The aim of this study was to evaluate the antifungal activity of SQS inhibitors on Candida albicans, Candida tropicalis and Candida parapsilopsis strains. Methods Ten arylquinuclidines that act as SQS inhibitors were tested as antiproliferative agents against three ATCC strains and 54 clinical isolates of Candida albicans, Candida tropicalis and Candida parapsilopsis. Also, the morphological alterations induced in the yeasts by the experimental compounds were evaluated by fluorescence and transmission electron microscopy. Results The most potent arylquinuclidine derivative (3-[1'-{4'-(benzyloxy-phenyl}]-quinuclidine-2-ene (WSP1267 had a MIC50 of 2 μg/ml for all species tested and MIC90 varying from 4 μg/ml to 8 μg/ml. Ultrathin sections of C. albicans treated with 1 μg/ml of WSP1267 showed several ultrastructural alterations, including (a loss of cell wall integrity, (b detachment of the plasma membrane from the fungal cell wall, (c accumulation of small vesicles in the periplasmic region, (d presence of large electron-dense vacuoles and (e significantly increased cell size and cell wall thickness. In addition, fluorescence microscopy of cells labelled with Nile Red showed an accumulation of lipid droplets in the cytoplasm of treated yeasts. Nuclear staining with DAPI revealed the appearance of uncommon yeast buds without a nucleus or with two nuclei. Conclusion Taken together, our data demonstrate that arylquinuclidine derivatives could be useful as lead compounds for the rational synthesis of new

Soluble factors from biofilm of Candida albicans and Staphylococcus aureus promote cell death and inflammatory response.

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de Carvalho Dias, Kassia; Barbugli, Paula Aboud; de Patto, Fernanda; Lordello, Virginia Barreto; de Aquino Penteado, Letícia; Medeiros, Alexandra Ivo; Vergani, Carlos Eduardo

2017-06-30

The objective of this study was to better understand the effects of soluble factors from biofilm of single- and mixed-species Candida albicans (C. albicans) and methicillin-sensitive Staphylococcus aureus (MSSA) cultures after 36 h in culture on keratinocytes (NOK-si and HaCaT) and macrophages (J774A.1). Soluble factors from biofilms of C. albicans and MSSA were collected and incubated with keratinocytes and macrophages, which were subsequently evaluated by cell viability assays (MTT). Lactate dehydrogenase (LDH) enzyme release was measured to assess cell membrane damage to keratinocytes. Cells were analysed by brightfield microscopy after 2 and 24 h of exposure to the soluble factors from biofilm. Cell death was detected by labelling apoptotic cells with annexin V and necrotic cells with propidium iodide (PI) and was visualized via fluorescence microscopy. Soluble factors from biofilm were incubated with J774A.1 cells for 24 h; the subsequent production of NO and the cytokines IL-6 and TNF-α was measured by ELISA. The cell viability assays showed that the soluble factors of single-species C. albicans cultures were as toxic as the soluble factors from biofilm of mixed cultures, whereas the soluble factors of MSSA cultures were less toxic than those of C. albicans or mixed cultures. The soluble factors from biofilm of mixed cultures were the most toxic to the NOK-si and HaCaT cells, as confirmed by analyses of PI labelling and cell morphology. Soluble factors from biofilm of single-species MSSA and mixed-species cultures induced the production of IL-6, NO and TNF-α by J744A.1 macrophages. The production of IL-6 and NO induced by the soluble factors from biofilm of mixed cultures was lower than that induced by the soluble factors from biofilm of single-species MSSA cultures, whereas the soluble factors from biofilm of C. albicans cultures induced only low levels of NO. Soluble factors from 36-h-old biofilm of C. albicans and MSSA cultures promoted cell death and

A relay network of extracellular heme-binding proteins drives C. albicans iron acquisition from hemoglobin.

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Kuznets, Galit; Vigonsky, Elena; Weissman, Ziva; Lalli, Daniela; Gildor, Tsvia; Kauffman, Sarah J; Turano, Paola; Becker, Jeffrey; Lewinson, Oded; Kornitzer, Daniel

2014-10-01

Iron scavenging constitutes a crucial challenge for survival of pathogenic microorganisms in the iron-poor host environment. Candida albicans, like many microbial pathogens, is able to utilize iron from hemoglobin, the largest iron pool in the host's body. Rbt5 is an extracellular glycosylphosphatidylinositol (GPI)-anchored heme-binding protein of the CFEM family that facilitates heme-iron uptake by an unknown mechanism. Here, we characterize an additional C. albicans CFEM protein gene, PGA7, deletion of which elicits a more severe heme-iron utilization phenotype than deletion of RBT5. The virulence of the pga7-/- mutant is reduced in a mouse model of systemic infection, consistent with a requirement for heme-iron utilization for C. albicans pathogenicity. The Pga7 and Rbt5 proteins exhibit distinct cell wall attachment, and discrete localization within the cell envelope, with Rbt5 being more exposed than Pga7. Both proteins are shown here to efficiently extract heme from hemoglobin. Surprisingly, while Pga7 has a higher affinity for heme in vitro, we find that heme transfer can occur bi-directionally between Pga7 and Rbt5, supporting a model in which they cooperate in a heme-acquisition relay. Together, our data delineate the roles of Pga7 and Rbt5 in a cell surface protein network that transfers heme from extracellular hemoglobin to the endocytic pathway, and provide a paradigm for how receptors embedded in the cell wall matrix can mediate nutrient uptake across the fungal cell envelope.

Sequential Dysfunction and Progressive Depletion of Candida albicans-Specific CD4 T Cell Response in HIV-1 Infection

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Liu, Fengliang; Fan, Xiuzhen; Auclair, Sarah; Ferguson, Monique; Sun, Jiaren; Soong, Lynn; Hou, Wei; Redfield, Robert R.; Birx, Deborah L.; Ratto-Kim, Silvia; Robb, Merlin L.; Kim, Jerome H.; Michael, Nelson L.; Hu, Haitao

2016-01-01

Loss of immune control over opportunistic infections can occur at different stages of HIV-1 (HIV) disease, among which mucosal candidiasis caused by the fungal pathogen Candida albicans (C. albicans) is one of the early and common manifestations in HIV-infected human subjects. The underlying immunological basis is not well defined. We have previously shown that compared to cytomegalovirus (CMV)-specific CD4 cells, C. albicans-specific CD4 T cells are highly permissive to HIV in vitro. Here, based on an antiretroviral treatment (ART) naïve HIV infection cohort (RV21), we investigated longitudinally the impact of HIV on C. albicans- and CMV-specific CD4 T-cell immunity in vivo. We found a sequential dysfunction and preferential depletion for C. albicans-specific CD4 T cell response during progressive HIV infection. Compared to Th1 (IFN-γ, MIP-1β) functional subsets, the Th17 functional subsets (IL-17, IL-22) of C. albicans-specific CD4 T cells were more permissive to HIV in vitro and impaired earlier in HIV-infected subjects. Infection history analysis showed that C. albicans-specific CD4 T cells were more susceptible to HIV in vivo, harboring modestly but significantly higher levels of HIV DNA, than CMV-specific CD4 T cells. Longitudinal analysis of HIV-infected individuals with ongoing CD4 depletion demonstrated that C. albicans-specific CD4 T-cell response was preferentially and progressively depleted. Taken together, these data suggest a potential mechanism for earlier loss of immune control over mucosal candidiasis in HIV-infected patients and provide new insights into pathogen-specific immune failure in AIDS pathogenesis. PMID:27280548

Culture Supernatants of Lactobacillus gasseri and L. crispatus Inhibit Candida albicans Biofilm Formation and Adhesion to HeLa Cells.

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Matsuda, Yuko; Cho, Otomi; Sugita, Takashi; Ogishima, Daiki; Takeda, Satoru

2018-03-30

Vulvovaginal candidiasis (VVC) is a common superficial infection of the vaginal mucous membranes caused by the fungus Candida albicans. The aim of this study was to assess the mechanisms underlying the inhibitory effects of the culture supernatants of Lactobacillus gasseri and L. crispatus, the predominant microbiota in Asian healthy women, on C. albicans biofilm formation. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was also investigated. Candida albicans biofilm was formed on polystyrene flat-bottomed 96-well plates, and the inhibitory effects on the initial colonization and maturation phases were determined using the XTT reduction assay. The expression levels of biofilm formation-associated genes (HWP1, ECE1, ALS3, BCR1, EFG1, TEC1, and CPH1) were determined by reverse transcription quantitative polymerase chain reaction. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was evaluated by enumerating viable C. albicans cells. The culture supernatants of both Lactobacillus species inhibited the initial colonization and maturation of C. albicans biofilm. The expression levels of all biofilm formation-related genes were downregulated in the presence of Lactobacillus culture supernatant. The culture supernatant also inhibited C. albicans adhesion to HeLa cells. The culture supernatants of L. gasseri and L. crispatus inhibited C. albicans biofilm formation by downregulating biofilm formation-related genes and C. albicans adhesion to HeLa cells. These findings support the notion that Lactobacillus metabolites may be useful alternatives to antifungal drugs for the management of VVC.

Als3 is a Candida albicans invasin that binds to cadherins and induces endocytosis by host cells.

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Quynh T Phan

2007-03-01

Full Text Available Candida albicans is the most common cause of hematogenously disseminated and oropharyngeal candidiasis. Both of these diseases are characterized by fungal invasion of host cells. Previously, we have found that C. albicans hyphae invade endothelial cells and oral epithelial cells in vitro by inducing their own endocytosis. Therefore, we set out to identify the fungal surface protein and host cell receptors that mediate this process. We found that the C. albicans Als3 is required for the organism to be endocytosed by human umbilical vein endothelial cells and two different human oral epithelial lines. Affinity purification experiments with wild-type and an als3delta/als3delta mutant strain of C. albicans demonstrated that Als3 was required for C. albicans to bind to multiple host cell surface proteins, including N-cadherin on endothelial cells and E-cadherin on oral epithelial cells. Furthermore, latex beads coated with the recombinant N-terminal portion of Als3 were endocytosed by Chinese hamster ovary cells expressing human N-cadherin or E-cadherin, whereas control beads coated with bovine serum albumin were not. Molecular modeling of the interactions of the N-terminal region of Als3 with the ectodomains of N-cadherin and E-cadherin indicated that the binding parameters of Als3 to either cadherin are similar to those of cadherin-cadherin binding. Therefore, Als3 is a fungal invasin that mimics host cell cadherins and induces endocytosis by binding to N-cadherin on endothelial cells and E-cadherin on oral epithelial cells. These results uncover the first known fungal invasin and provide evidence that C. albicans Als3 is a molecular mimic of human cadherins.

Selection of aptamers for Candida albicans by cell-SELEX

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Miranda, Alessandra Nunes Duarte

2017-01-01

The growing concern with invasive fungal infections, responsible for an alarming mortality rate of immunosuppressed patients and in Intensive Care Units, evidences the need for a fast and specific method for the Candida albicans detection, since this species is identified as one of the main causes of septicemia. Commonly, it is a challenge for clinicians to determine the primary infection foci, the dissemination degree, or whether the site of a particular surgery is involved. Although scintigraphic imaging represents a promising tool for infectious foci detection, it still lacks a methodology for C. albicans diagnosis due to the absence of specific radiotracers for this microorganism. Aptamers are molecules that have almost ideal properties for use as diagnostic radiopharmaceuticals, such as high specificity for their molecular targets, lack of immunogenicity and toxicity, high tissue penetration and rapid blood clearance. Aptamers can also be labeled with different radionuclides. This work aims to obtain aptamers for specific binding to C. albicans cells for future application as a radiopharmaceutical. It was used a variation of the SELEX (Systematic Evolution of Ligands by EXponential Enrichment) technique, termed cell-SELEX, in which cells are the targets for selection. A selection protocol was standardized using a random library of single-stranded oligonucleotides, each containing two fixed regions flanking a sequence of 40 random nucleotides. This library was incubated with C. albicans cells in the presence of competitors. Then, the binding sequences were separated by centrifugation, resuspended and amplified by PCR. The amplification was confirmed by agarose gel electrophoresis. After that, the ligands were purified to obtain a new pool of ssDNA, from which a new incubation was carried out. The selection parameters were gradually modified in order to increase stringency. This cycle was repeated 12 times to allow the selection of sequences with the maximum

White cells facilitate opposite- and same-sex mating of opaque cells in Candida albicans.

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Li Tao

2014-10-01

Full Text Available Modes of sexual reproduction in eukaryotic organisms are extremely diverse. The human fungal pathogen Candida albicans undergoes a phenotypic switch from the white to the opaque phase in order to become mating-competent. In this study, we report that functionally- and morphologically-differentiated white and opaque cells show a coordinated behavior during mating. Although white cells are mating-incompetent, they can produce sexual pheromones when treated with pheromones of the opposite mating type or by physically interacting with opaque cells of the opposite mating type. In a co-culture system, pheromones released by white cells induce opaque cells to form mating projections, and facilitate both opposite- and same-sex mating of opaque cells. Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1 impair the promoting role of white cells (MTLa in the sexual mating of opaque cells. White and opaque cells communicate via a paracrine pheromone signaling system, creating an environment conducive to sexual mating. This coordination between the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans.

[Effects of non-saccharomyces albicans metabolic products on the proliferation of human umbilical vein endothelial cell ECV304].

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Chen, Bin; Che, Tuanjie; Bai, Decheng; He, Xiangyi

2013-04-01

To evaluate the effects of non-Saccharomyces albicans metabolic products on the cell cycle distribution and proliferation of human umbilical vein endothelial cell ECV304 cells in vitro. The parallel dilution supernatant of Saccharomyces tropicalis, Saccharomyces krusei and Saccharomyces glabrata were prepared, and 1, 4, 16-fold(s) diluted concentration and control group were set up. The line of human umbilical vein endothelial cell ECV304 was cultured in vitro and treated by non-Saccharomyces albicans supernatant. The proliferous effect of ECV304 induced by non-Saccharomyces albicans supernatant after 24, 48, 72 h was detected by the methods of MTT, and the changes of cell density and cycle after 48 h were investigated by inverted microscope and flow cytometry. At the 24th hour, all of the higher concentration (1-fold) of non-Saccharomyces albicans supernatant and the 4-folds diluted Saccharomyces krusei could promote ECV304 proliferation(P Saccharomyces albicans supernatant at 48h and 72th hour, Saccharomyces krusei supernatant and Saccharomyces glabrata supernatant significantly increased proliferation rate of ECV304, while Saccharomyces tropicalis supernatant group showed no significant change no matter which concentration was tested. At 48th hour after adding the non-Saccharomyces albicans supernatant, the ECV304 cells density treated by Saccharomyces krusei supernatant and Saccharomyces glabrata supernatant were significantly higher under the inverted microscope. The G0/G1 population of ECV304 cells decreased while cell proliferation index (PI) increased after incubated with Saccharomyces krusei supernatant and Saccharomyces glabrata supernatant for 48 hours (P Saccharomyces tropicalis group showed no significant change (P > 0.05). The metabolic products of Sacharoymces krusei and Saccharomyces glabrata could induce proliferation of ECV304 cell, which suggests non-Saccharomyces albicans should be undergone more attention clinically in detection and treatment.

Binary Interactions of Antagonistic Bacteria with Candida albicans Under Aerobic and Anaerobic Conditions.

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Benadé, Eliska; Stone, Wendy; Mouton, Marnel; Postma, Ferdinand; Wilsenach, Jac; Botha, Alfred

2016-04-01

We used both aerobic and anaerobic liquid co-cultures, prepared with Luria Bertani broth, to study the effect of bacteria on the survival of Candida albicans in the external environment, away from an animal host. The bacteria were represented by Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Clostridium, Enterobacter, Klebsiella pneumoniae, Kluyvera ascorbata and Serratia marcescens. Under aerobic conditions, the yeast's growth was inhibited in the presence of bacterial growth; however, under anaerobic conditions, yeast and bacterial growth in co-cultures was similar to that observed for pure cultures. Subsequent assays revealed that the majority of bacterial strains aerobically produced extracellular hydrolytic enzymes capable of yeast cell wall hydrolysis, including chitinases and mannan-degrading enzymes. In contrast, except for the A. hydrophila strain, these enzymes were not detected in anaerobic bacterial cultures, nor was the antimicrobial compound prodigiosin found in anaerobic cultures of S. marcescens. When we suspended C. albicans cells in crude extracellular enzyme preparations from K. pneumoniae and S. marcescens, we detected no negative effect on yeast viability. However, we found that these preparations enhance the toxicity of prodigiosin towards the yeast, especially in combination with mannan-degrading enzymes. Analyses of the chitin and mannan content of yeast cell walls revealed that less chitin was produced under anaerobic than aerobic conditions; however, the levels of mannan, known for its low permeability, remained the same. The latter phenomenon, as well as reduced production of the bacterial enzymes and prodigiosin, may contribute to anaerobic growth and survival of C. albicans in the presence of bacteria.

Purification and germination of Candida albicans and Candida dubliniensis chlamydospores cultured in liquid media

OpenAIRE

Citiulo, Francesco; Moran, Gary; COLEMAN, DAVID; SULLIVAN, DEREK

2009-01-01

PUBLISHED Candida albicans and Candida dubliniensis are the only Candida species that have been observed to produce chlamydospores. The function of these large, thick-walled cells is currently unknown. In this report we describe the production and purification of chlamydospores from these species in defined liquid media. Staining with the fluorescent dye FUN-1 indicated that chlamydospores are metabolically active cells, but that metabolic activity is undetectable in chlamydospores that...

The Discovery of a Potential Antimicrobial Agent: the Novel Compound Natural Medicinal Plant Fermentation Extracts against Candida albicans

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Song, Mingzhu; Wang, Xirui; Mao, Canquan; Yao, Wei

2018-01-01

Natural medicinal plants and their extracts are important sources of antimicrobial drug development. In this study, we reported an ancient formula of Chinese folk medicine, the compound natural medicinal plant fermentation extracts (CNMPFE) for its antimicrobial effects. The effects and mechanisms of CNMPFE on C. albicans were studied by cell damage experiments including antimicrobial kinetics, fungal growth curve, alkaline phosphatase (AKP) activity, ultraviolet absorption, electric conductivity and the evaluation of cellular ultra microstructure. The results showed that the minimal inhibitory concentration and minimum fungicidal concentration of CNMPFE against C. albicans were 75% (vol/vol) and 80% (vol/vol) respectively. The inhibition of CNMPFE for C. albicans was dose and time dependent, based on increasing of the AKP activities and the ultraviolet absorptions and the electric conductivities of the fungal solutions, it may exert its antifungal properties by disrupting the structure of cell wall and the cell membrane integrity and their permeability, subsequently resulting in cell death. Taken together, these findings suggest that CNMPFE may be a promising drug candidate for the treatment of fungal infections skin diseases.

Binding of Candida albicans to Human CEACAM1 and CEACAM6 Modulates the Inflammatory Response of Intestinal Epithelial Cells

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Esther Klaile

2017-03-01

Full Text Available Candida albicans colonizes human mucosa, including the gastrointestinal tract, as a commensal. In immunocompromised patients, C. albicans can breach the intestinal epithelial barrier and cause fatal invasive infections. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1; CD66a, CEACAM5 (CEA, and CEACAM6 (CD66c are immunomodulatory receptors expressed on human mucosa and are recruited by bacterial and viral pathogens. Here we show for the first time that a fungal pathogen (i.e., C. albicans also binds directly to the extracellular domain of human CEACAM1, CEACAM3, CEACAM5, and CEACAM6. Binding was specific for human CEACAMs and mediated by the N-terminal IgV-like domain. In enterocytic C2BBe1 cells, C. albicans caused a transient tyrosine phosphorylation of CEACAM1 and induced higher expression of membrane-bound CEACAM1 and soluble CEACAM6. Lack of the CEACAM1 receptor after short hairpin RNA (shRNA knockdown abolished CXCL8 (interleukin-8 secretion by C2BBe1 cells in response to C. albicans. In CEACAM1-competent cells, the addition of recombinant soluble CEACAM6 reduced the C. albicans-induced CXCL8 secretion.

How to prevent contamination with Candida albicans during the fabrication of transplantable oral mucosal epithelial cell sheets

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Ryo Takagi

2015-06-01

Full Text Available We have utilized patients' own oral mucosa as a cell source for the fabrication of transplantable epithelial cell sheets to treat limbal stem cell deficiency and mucosal defects after endoscopic submucosal dissection of esophageal cancer. Because there are abundant microbiotas in the human oral cavity, the oral mucosa was sterilized and 40 μg/mL gentamicin and 0.27 μg/mL amphotericin B were added to the culture medium in our protocol. Although an oral surgeon carefully checked each patient's oral cavity and although candidiasis was not observed before taking the biopsy, contamination with Candida albicans (C. albicans was detected in the conditioned medium during cell sheet fabrication. After adding 1 μg/mL amphotericin B to the transportation medium during transport from Nagasaki University Hospital to Tokyo Women's Medical University, which are 1200 km apart, no proliferation of C. albicans was observed. These results indicated that the supplementation of transportation medium with antimycotics would be useful for preventing contamination with C. albicans derived from the oral mucosa without hampering cell proliferation.

In vitro Effects of Lemongrass Extract on Candida albicans Biofilms, Human Cells Viability, and Denture Surface.

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Madeira, Petrus L B; Carvalho, Letícia T; Paschoal, Marco A B; de Sousa, Eduardo M; Moffa, Eduardo B; da Silva, Marcos A Dos Santos; Tavarez, Rudys de Jesus Rodolfo; Gonçalves, Letícia M

2016-01-01

The purpose of this study was to investigate whether immersion of a denture surface in lemongrass extract (LGE) has effects on C. albicans biofilms, human cell viability and denture surface. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) were performed for LGE against C. albicans. For biofilm analysis, discs were fabricated using a denture acrylic resin with surface roughness standardization. C. albicans biofilms were developed on saliva-coated discs, and the effects of LGE at MIC, 5XMIC, and 10XMIC were investigated during biofilm formation and after biofilm maturation. Biofilms were investigated for cell counting, metabolic activity, and microscopic analysis. The cytotoxicity of different concentrations of LGE to peripheral blood mononuclear cells (PBMC) was analyzed using MTT. The effects of LGE on acrylic resin were verified by measuring changes in roughness, color and flexural strength after 28 days of immersion. Data were analyzed by ANOVA, followed by a Tukey test at a 5% significance level. The minimal concentration of LGE required to inhibit C. albicans growth was 0.625 mg/mL, while MFC was 2.5 mg/mL. The presence of LGE during biofilm development resulted in a reduction of cell counting (p 0.05). There were no verified differences in color perception, roughness, or flexural strength after immersion in LGE at MIC compared to the control (p > 0.05). It could be concluded that immersion of the denture surface in LGE was effective in reducing C. albicans biofilms with no deleterious effects on acrylic properties at MIC. MIC was also an effective and safe concentration for use.

Dynamic, morphotype-specific Candida albicans beta-glucan exposure during infection and drug treatment.

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Robert T Wheeler

2008-12-01

Full Text Available Candida albicans, a clinically important dimorphic fungal pathogen that can evade immune attack by masking its cell wall beta-glucan from immune recognition, mutes protective host responses mediated by the Dectin-1 beta-glucan receptor on innate immune cells. Although the ability of C. albicans to switch between a yeast- or hyphal-form is a key virulence determinant, the role of each morphotype in beta-glucan masking during infection and treatment has not been addressed. Here, we show that during infection of mice, the C. albicans beta-glucan is masked initially but becomes exposed later in several organs. At all measured stages of infection, there is no difference in beta-glucan exposure between yeast-form and hyphal cells. We have previously shown that sub-inhibitory doses of the anti-fungal drug caspofungin can expose beta-glucan in vitro, suggesting that the drug may enhance immune activity during therapy. This report shows that caspofungin also mediates beta-glucan unmasking in vivo. Surprisingly, caspofungin preferentially unmasks filamentous cells, as opposed to yeast form cells, both in vivo and in vitro. The fungicidal activity of caspofungin in vitro is also filament-biased, as corroborated using yeast-locked and hyphal-locked mutants. The uncloaking of filaments is not a general effect of anti-fungal drugs, as another anti-fungal agent does not have this effect. These results highlight the advantage of studying host-pathogen interaction in vivo and suggest new avenues for drug development.

Candida albicans: The Ability to Invade Epithelial Cells and Survive under Oxidative Stress Is Unlinked to Hyphal Length

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Paloma K. Maza

2017-07-01

Full Text Available In its hyphal form, Candida albicans invades epithelial and endothelial cells by two distinct mechanisms: active penetration and induced endocytosis. The latter is dependent on a reorganization of the host cytoskeleton (actin/cortactin recruitment, whilst active penetration does not rely on the host's cellular machinery. The first obstacle for the fungus to reach deep tissues is the epithelial barrier and this interaction is crucial for commensal growth, fungal pathogenicity and host defense. This study aimed to characterize in vitro epithelial HeLa cell invasion by four different isolates of C. albicans with distinct clinical backgrounds, including a C. albicans SC5314 reference strain. All isolates invaded HeLa cells, recruited actin and cortactin, and induced the phosphorylation of both Src-family kinases (SFK and cortactin. Curiously, L3881 isolated from blood culture of a patient exhibited the highest resistance to oxidative stress, although this isolate showed reduced hyphal length and displayed the lowest cell damage and invasion rates. Collectively, these data suggest that the ability of C. albicans to invade HeLa cells, and to reach and adapt to the host's blood, including resistance to oxidative stress, may be independent of hyphal length.

PgTeL, the lectin found in Punica granatum juice, is an antifungal agent against Candida albicans and Candida krusei.

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da Silva, Pollyanna Michelle; de Moura, Maiara Celine; Gomes, Francis Soares; da Silva Trentin, Danielle; Silva de Oliveira, Ana Patrícia; de Mello, Gabriela Souto Vieira; da Rocha Pitta, Maira Galdino; de Melo Rego, Moacyr Jesus Barreto; Coelho, Luana Cassandra Breitenbach Barroso; Macedo, Alexandre José; de Figueiredo, Regina Celia Bressan Queiroz; Paiva, Patrícia Maria Guedes; Napoleão, Thiago Henrique

2018-03-01

The pomegranate (Punica granatum) sarcotesta contains a chitin-binding lectin (PgTeL) with antibacterial activity against human pathogenic species. In this work, the structural stability of PgTeL was evaluated by fluorimetric analysis and the lectin was evaluated for cytotoxicity to human peripheral blood mononuclear cells (PBMCs) and antifungal activity against Candida albicans and Candida krusei. PgTeL folding was impaired when lectin was incubated at pH≥6.0. On the other hand, the lectin did not undergo unfolding even when heated at 100°C. PgTeL (1, 10, and 100μg/mL) was not cytotoxic to PBMCs. Antifungal activity was detected for C. albicans (MIC: 25μg/mL; MFC: 50μg/mL) and C. krusei (MIC and MFC of 12.5μg/mL). Treatment of yeast cells with PgTeL resulted in decrease of intracellular ATP content even at sub-inhibitory concentrations (½MIC and ¼MIC) and induced lipid peroxidation. In addition, PgTeL damaged the integrity of fungal cell wall of both species, with more pronounced effects in C. krusei. The lectin showed significant antibiofilm activity on C. albicans at sub-inhibitory concentrations (0.195 and 0.39μg/mL). In conclusion, PgTeL is an anti-Candida agent whose action mechanism involves oxidative stress, energetic collapse, damage to the cell wall and rupture of yeast cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Therapeutic potential of thiazolidinedione-8 as an antibiofilm agent against Candida albicans.

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Mark Feldman

Full Text Available Candida albicans is known as a commensal microorganism but it is also the most common fungal pathogen in humans, causing both mucosal and systemic infections. Biofilm-associated C. albicans infections present clinically important features due to their high levels of resistance to traditional antifungal agents. Quorum sensing is closely associated with biofilm formation and increasing fungal pathogenicity. We investigated the ability of the novel bacterial quorum sensing quencher thiazolidinedione-8 (S-8 to inhibit the formation of, and eradication of mature C. albicans biofilms. In addition, the capability of S-8 to alter fungal adhesion to mammalian cells was checked. S-8 exhibited specific antibiofilm and antiadhesion activities against C. albicans, at four- to eightfold lower concentrations than the minimum inhibitory concentration (MIC. Using fluorescence microscopy, we observed that S-8 dose-dependently reduces C. albicans-GFP binding to RAW macrophages. S-8 at sub-MICs also interfered with fungal morphogenesis by inhibiting the yeast-to-hyphal form transition. In addition, the tested agent strongly affected fungal cell wall characteristics by modulating its hydrophobicity. We evaluated the molecular mode of S-8 antibiofilm and antiadhesion activities using real-time RT-PCR. The expression levels of genes associated with biofilm formation, adhesion and filamentation, HWP1, ALS3 and EAP1, respectively, were dose-dependently downregulated by S-8. Transcript levels of UME6, responsible for long-term hyphal maintenance, were also significantly decreased by the tested agent. Both signaling pathways of hyphal formation-cAMP-PKA and MAPK-were interrupted by S-8. Their upstream general regulator RAS1 was markedly suppressed by S-8. In addition, the expression levels of MAPK cascade components CST20, HST7 and CPH1 were downregulated by S-8. Finally, transcriptional repressors of filament formation, TUP1 and NRG1, were dramatically upregulated by our

Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

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Levin, David E.

2011-01-01

The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to the Rho1 GTPase, which mobilizes a physiologic response through a variety of effectors. Activation of CWI signaling regulates the production of various carbohydrate polymers of the cell wall, as well as their polarized delivery to the site of cell wall remodeling. This review article centers on CWI signaling in Saccharomyces cerevisiae through the cell cycle and in response to cell wall stress. The interface of this signaling pathway with other pathways that contribute to the maintenance of cell wall integrity is also discussed. PMID:22174182

Genetic and phenotypic intra-species variation in Candida albicans.

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Hirakawa, Matthew P; Martinez, Diego A; Sakthikumar, Sharadha; Anderson, Matthew Z; Berlin, Aaron; Gujja, Sharvari; Zeng, Qiandong; Zisson, Ethan; Wang, Joshua M; Greenberg, Joshua M; Berman, Judith; Bennett, Richard J; Cuomo, Christina A

2015-03-01

Candida albicans is a commensal fungus of the human gastrointestinal tract and a prevalent opportunistic pathogen. To examine diversity within this species, extensive genomic and phenotypic analyses were performed on 21 clinical C. albicans isolates. Genomic variation was evident in the form of polymorphisms, copy number variations, chromosomal inversions, subtelomeric hypervariation, loss of heterozygosity (LOH), and whole or partial chromosome aneuploidies. All 21 strains were diploid, although karyotypic changes were present in eight of the 21 isolates, with multiple strains being trisomic for Chromosome 4 or Chromosome 7. Aneuploid strains exhibited a general fitness defect relative to euploid strains when grown under replete conditions. All strains were also heterozygous, yet multiple, distinct LOH tracts were present in each isolate. Higher overall levels of genome heterozygosity correlated with faster growth rates, consistent with increased overall fitness. Genes with the highest rates of amino acid substitutions included many cell wall proteins, implicating fast evolving changes in cell adhesion and host interactions. One clinical isolate, P94015, presented several striking properties including a novel cellular phenotype, an inability to filament, drug resistance, and decreased virulence. Several of these properties were shown to be due to a homozygous nonsense mutation in the EFG1 gene. Furthermore, loss of EFG1 function resulted in increased fitness of P94015 in a commensal model of infection. Our analysis therefore reveals intra-species genetic and phenotypic differences in C. albicans and delineates a natural mutation that alters the balance between commensalism and pathogenicity. © 2015 Hirakawa et al.; Published by Cold Spring Harbor Laboratory Press.

Candida albicans induces Metabolic Reprogramming in human NK cells and responds to Perforin with a Zinc Depletion Response

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Daniela eHellwig

2016-05-01

Full Text Available As part of the innate immune system, natural killer (NK cells are directly involved in the response to fungal infections. Perforin has been identified as the major effector molecule acting against many fungal pathogens. While several studies have shown that perforin mediated fungicidal effects can contribute to fungal clearance, neither the activation of NK cells by fungal pathogens nor the effects of perforin on fungal cells are well understood. In a dual approach, we have studied the global gene expression pattern of primary and cytokine activated NK cells after co-incubation with C. albicans and the transcriptomic adaptation of C. albicans to perforin exposure. NK cells responded to the fungal pathogen with an up-regulation of genes involved in immune signaling and release of cytokines. Furthermore, we observed a pronounced increase of genes involved in glycolysis and glycolysis inhibitor 2-deoxy-D-glucose impaired C. albicans induced NK cell activation. This strongly indicates that metabolic adaptation is a major part of the NK cell response to C. albicans infections. In the fungal pathogen, perforin induced a strong up-regulation of several fungal genes involved in the zinc depletion response, such as PRA1 and ZRT1. These data suggest that fungal zinc homeostasis is linked to the reaction to perforin secreted by NK cells. However, deletion mutants in PRA1 and ZRT1 did not show altered susceptibility to perforin.

AFM force spectroscopy reveals how subtle structural differences affect the interaction strength between Candida albicans and DC-SIGN.

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te Riet, Joost; Reinieren-Beeren, Inge; Figdor, Carl G; Cambi, Alessandra

2015-11-01

The fungus Candida albicans is the most common cause of mycotic infections in immunocompromised hosts. Little is known about the initial interactions between Candida and immune cell receptors, such as the C-type lectin dendritic cell-specific intracellular cell adhesion molecule-3 (ICAM-3)-grabbing non-integrin (DC-SIGN), because a detailed characterization at the structural level is lacking. DC-SIGN recognizes specific Candida-associated molecular patterns, that is, mannan structures present in the cell wall of Candida. The molecular recognition mechanism is however poorly understood. We postulated that small differences in mannan-branching may result in considerable differences in the binding affinity. Here, we exploit atomic force microscope-based dynamic force spectroscopy with single Candida cells to gain better insight in the carbohydrate recognition capacity of DC-SIGN. We demonstrate that slight differences in the N-mannan structure of Candida, that is, the absence or presence of a phosphomannan side chain, results in differences in the recognition by DC-SIGN as follows: (i) it contributes to the compliance of the outer cell wall of Candida, and (ii) its presence results in a higher binding energy of 1.6 kB T. The single-bond affinity of tetrameric DC-SIGN for wild-type C. albicans is ~10.7 kB T and a dissociation constant kD of 23 μM, which is relatively strong compared with other carbohydrate-protein interactions described in the literature. In conclusion, this study shows that DC-SIGN specifically recognizes mannan patterns on C. albicans with high affinity. Knowledge on the binding pocket of DC-SIGN and its pathogenic ligands will lead to a better understanding of how fungal-associated carbohydrate structures are recognized by receptors of the immune system and can ultimately contribute to the development of new anti-fungal drugs. Copyright © 2015 John Wiley & Sons, Ltd.

Biophysical Effects of a Polymeric Biosurfactant in Candida krusei and Candida albicans Cells.

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Ferreira, Gabriella Freitas; Dos Santos Pinto, Bruna Lorrana; Souza, Eliene Batista; Viana, José Lima; Zagmignan, Adrielle; Dos Santos, Julliana Ribeiro Alves; Santos, Áquila Rodrigues Costa; Tavares, Priscila Batista; Denadai, Ângelo Márcio Leite; Monteiro, Andrea Souza

2016-12-01

This study evaluated the effects of a polymeric biosurfactant produced by Trichosporon montevideense CLOA72 in the adhesion of Candida albicans and Candida krusei cells to human buccal epithelial cells and its interference in biofilm formation by these strains. The biofilm inhibition by biosurfactant (25 mg/mL) in C. krusei and C. albicans in polystyrene was reduced up to 79.5 and 85 %, respectively. In addition, the zeta potential and hydrodynamic diameter of the yeasts altered as a function of the biosurfactant concentration added to the cell suspension. The changes in the cell surface characteristics and the interface modification can contribute to the inhibition of the initial adherence of yeasts cells to the surface. In addition, the analyses of the biofilm matrix and planktonic cell surfaces demonstrated differences in carbohydrate and protein concentrations for the two studied strains, which may contribute to the modulation of cell adhesion or consolidation of biofilms, especially in C. krusei. This study suggests a possible application of the of CLOA72 biosurfactant in inhibiting the adhesion and formation of biofilms on biological surfaces by yeasts of the Candida genus.

Lactobacillus crispatus Modulates Vaginal Epithelial Cell Innate Response to Candida albicans

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Xiao-Xi Niu

2017-01-01

Conclusions: L. crispatus can attenuate the virulence of C. albicans, modulate the secretion of cytokines and chemokines, and enhance the immune response of VK2/E6E7 cells in vitro. The vaginal mucosa has a potential function in the local immune responses against pathogens that can be promoted by L. crispatus.

Plant cell wall extensibility: connecting plant cell growth with cell wall structure, mechanics, and the action of wall-modifying enzymes

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Cosgrove, Daniel J.

2015-11-25

The advent of user-friendly instruments for measuring force/deflection curves of plant surfaces at high spatial resolution has resulted in a recent outpouring of reports of the ‘Young's modulus’ of plant cell walls. The stimulus for these mechanical measurements comes from biomechanical models of morphogenesis of meristems and other tissues, as well as single cells, in which cell wall stress feeds back to regulate microtubule organization, auxin transport, cellulose deposition, and future growth directionality. In this article I review the differences between elastic modulus and wall extensibility in the context of cell growth. Some of the inherent complexities, assumptions, and potential pitfalls in the interpretation of indentation force/deflection curves are discussed. Reported values of elastic moduli from surface indentation measurements appear to be 10- to >1000-fold smaller than realistic tensile elastic moduli in the plane of plant cell walls. Potential reasons for this disparity are discussed, but further work is needed to make sense of the huge range in reported values. The significance of wall stress relaxation for growth is reviewed and connected to recent advances and remaining enigmas in our concepts of how cellulose, hemicellulose, and pectins are assembled to make an extensible cell wall. A comparison of the loosening action of α-expansin and Cel12A endoglucanase is used to illustrate two different ways in which cell walls may be made more extensible and the divergent effects on wall mechanics.

Induction of suppressor cells in vitro by Candida albicans.

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Cuff, C F; Rogers, C M; Lamb, B J; Rogers, T J

1986-06-01

Normal splenocytes cultured with Formalin-killed Candida albicans were shown to acquire significant suppressor cell activity in a period of 3 days. These cells were found to suppress both the phytohemagglutinin-induced mitogen response as well as the anti-sheep erythrocyte antibody response. Experiments were carried out to determine the nature of the suppressor cell population. Results showed that these cells were not susceptible to treatment with anti-Thy 1 antibody and complement. Panning experiments showed that the suppressor cells were not plastic-adherent or Mac-1 antigen-positive. The suppressor cells were, however, adherent to anti-mouse immunoglobulin (F(ab')2-fragment)-coated dishes. Additional experiments showed that the suppressor cell activity was susceptible to treatment with monoclonal anti-Lyb 2.1 antibody and complement. These results suggest that the suppressor cell induced in vitro by Candida is a member of the B-lymphocyte lineage.

The MARVEL domain protein Nce102 regulates actin organization and invasive growth of Candida albicans.

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Douglas, Lois M; Wang, Hong X; Konopka, James B

2013-11-26

Invasive growth of the fungal pathogen Candida albicans into tissues promotes disseminated infections in humans. The plasma membrane is essential for pathogenesis because this important barrier mediates morphogenesis and invasive growth, as well as secretion of virulence factors, cell wall synthesis, nutrient import, and other processes. Previous studies showed that the Sur7 tetraspan protein that localizes to MCC (membrane compartment occupied by Can1)/eisosome subdomains of the plasma membrane regulates a broad range of key functions, including cell wall synthesis, morphogenesis, and resistance to copper. Therefore, a distinct tetraspan protein found in MCC/eisosomes, Nce102, was investigated. Nce102 belongs to the MARVEL domain protein family, which is implicated in regulating membrane structure and function. Deletion of NCE102 did not cause the broad defects seen in sur7Δ cells. Instead, the nce102Δ mutant displayed a unique phenotype in that it was defective in forming hyphae and invading low concentrations of agar but could invade well in higher agar concentrations. This phenotype was likely due to a defect in actin organization that was observed by phalloidin staining. In support of this, the invasive growth defect of a bni1Δ mutant that mislocalizes actin due to lack of the Bni1 formin was also reversed at high agar concentrations. This suggests that a denser matrix provides a signal that compensates for the actin defects. The nce102Δ mutant displayed decreased virulence and formed abnormal hyphae in mice. These studies identify novel ways that Nce102 and the physical environment surrounding C. albicans regulate morphogenesis and pathogenesis. The plasma membrane promotes virulence of the human fungal pathogen Candida albicans by acting as a protective barrier around the cell and mediating dynamic activities, such as morphogenesis, cell wall synthesis, secretion of virulence factors, and nutrient uptake. To better understand how the plasma membrane

The Absence of N-Acetyl-D-glucosamine Causes Attenuation of Virulence of Candida albicans upon Interaction with Vaginal Epithelial Cells In Vitro

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Máté Manczinger

2015-01-01

Full Text Available To better understand the molecular events underlying vulvovaginal candidiasis, we established an in vitro system. Immortalized vaginal epithelial cells were infected with live, yeast form C. albicans and C. albicans cultured in the same medium without vaginal epithelial cells were used as control. In both cases a yeast to hyphae transition was robustly induced. Whole transcriptome sequencing was used to identify specific gene expression changes in C. albicans. Numerous genes leading to a yeast to hyphae transition and hyphae specific genes were upregulated in the control hyphae and the hyphae in response to vaginal epithelial cells. Strikingly, the GlcNAc pathway was exclusively triggered by vaginal epithelial cells. Functional analysis in our in vitro system revealed that the GlcNAc biosynthesis is involved in the adherence to, and the ability to kill, vaginal epithelial cells in vitro, thus indicating the key role for this pathway in the virulence of C. albicans upon vulvovaginal candidiasis.

The Absence of N-Acetyl-D-glucosamine Causes Attenuation of Virulence of Candida albicans upon Interaction with Vaginal Epithelial Cells In Vitro

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Manczinger, Máté; Bocsik, Alexandra; Kocsis, Gabriella F.; Vörös, Andrea; Hegedűs, Zoltán; Marton, Annamária; Vízler, Csaba; Tubak, Vilmos; Deli, Mária; Kemény, Lajos; Nagy, István; Lakatos, Lóránt

2015-01-01

To better understand the molecular events underlying vulvovaginal candidiasis, we established an in vitro system. Immortalized vaginal epithelial cells were infected with live, yeast form C. albicans and C. albicans cultured in the same medium without vaginal epithelial cells were used as control. In both cases a yeast to hyphae transition was robustly induced. Whole transcriptome sequencing was used to identify specific gene expression changes in C. albicans. Numerous genes leading to a yeast to hyphae transition and hyphae specific genes were upregulated in the control hyphae and the hyphae in response to vaginal epithelial cells. Strikingly, the GlcNAc pathway was exclusively triggered by vaginal epithelial cells. Functional analysis in our in vitro system revealed that the GlcNAc biosynthesis is involved in the adherence to, and the ability to kill, vaginal epithelial cells in vitro, thus indicating the key role for this pathway in the virulence of C. albicans upon vulvovaginal candidiasis. PMID:26366412

Regulation of cell wall biosynthesis.

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Zhong, Ruiqin; Ye, Zheng-Hua

2007-12-01

Plant cell walls differ in their amount and composition among various cell types and even in different microdomains of the wall of a given cell. Plants must have evolved regulatory mechanisms controlling biosynthesis, targeted secretion, and assembly of wall components to achieve the heterogeneity in cell walls. A number of factors, including hormones, the cytoskeleton, glycosylphosphatidylinositol-anchored proteins, phosphoinositides, and sugar nucleotide supply, have been implicated in the regulation of cell wall biosynthesis or deposition. In the past two years, there have been important discoveries in transcriptional regulation of secondary wall biosynthesis. Several transcription factors in the NAC and MYB families have been shown to be the key switches for activation of secondary wall biosynthesis. These studies suggest a transcriptional network comprised of a hierarchy of transcription factors is involved in regulating secondary wall biosynthesis. Further investigation and integration of the regulatory players participating in the making of cell walls will certainly lead to our understanding of how wall amounts and composition are controlled in a given cell type. This may eventually allow custom design of plant cell walls on the basis of our needs.

Effect of Piper betle and Brucea javanica on the Differential Expression of Hyphal Wall Protein (HWP1) in Non-Candida albicans Candida (NCAC) Species.

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Wan Harun, Wan Himratul Aznita; Jamil, Nur Alyaa; Jamaludin, Nor Hazwani; Nordin, Mohd-Al-Faisal

2013-01-01

The study aimed to identify the HWP1 gene in non-Candida albicans Candida species and the differential expression of HWP1 following treatment with Piper betle and Brucea javanica aqueous extracts. All candidal suspensions were standardized to 1 × 10(6) cells/mL. The suspension was incubated overnight at 37 °C (C. parapsilosis, 35°C). Candidal cells were treated with each respective extract at 1, 3, and 6 mg/mL for 24 h. The total RNA was extracted and reverse transcription-polymerase chain reaction was carried out with a specific primer of HWP1. HWP1 mRNAs were only detected in C. albicans, C. parapsilosis, and C. tropicalis. Exposing the cells to the aqueous extracts has affected the expression of HWP1 transcripts. C. albicans, C. parapsilosis, and C. tropicalis have demonstrated different intensity of mRNA. Compared to P. betle, B. javanica demonstrated a higher suppression on the transcript levels of HWP1 in all samples. HWP1 was not detected in C. albicans following the treatment of B. javanica at 1 mg/mL. In contrast, C. parapsilosis and C. tropicalis were shown to have HWP1 regulation. However, the expression levels were reduced upon the addition of higher concentration of B. javanica extract. P. betle and B. javanica have potential to be developed as oral health product.

The functions of Mediator in Candida albicans support a role in shaping species-specific gene expression.

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Nathalie Uwamahoro

Full Text Available The Mediator complex is an essential co-regulator of RNA polymerase II that is conserved throughout eukaryotes. Here we present the first study of Mediator in the pathogenic fungus Candida albicans. We focused on the Middle domain subunit Med31, the Head domain subunit Med20, and Srb9/Med13 from the Kinase domain. The C. albicans Mediator shares some roles with model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, such as functions in the response to certain stresses and the role of Med31 in the expression of genes regulated by the activator Ace2. The C. albicans Mediator also has additional roles in the transcription of genes associated with virulence, for example genes related to morphogenesis and gene families enriched in pathogens, such as the ALS adhesins. Consistently, Med31, Med20, and Srb9/Med13 contribute to key virulence attributes of C. albicans, filamentation, and biofilm formation; and ALS1 is a biologically relevant target of Med31 for development of biofilms. Furthermore, Med31 affects virulence of C. albicans in the worm infection model. We present evidence that the roles of Med31 and Srb9/Med13 in the expression of the genes encoding cell wall adhesins are different between S. cerevisiae and C. albicans: they are repressors of the FLO genes in S. cerevisiae and are activators of the ALS genes in C. albicans. This suggests that Mediator subunits regulate adhesion in a distinct manner between these two distantly related fungal species.

Mechanistic insight of the photodynamic effect induced by tri- and tetra-cationic porphyrins on Candida albicans cells.

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Cormick, M Paula; Quiroga, Ezequiel D; Bertolotti, Sonia G; Alvarez, M Gabriela; Durantini, Edgardo N

2011-10-01

The photodynamic mechanism of action induced by 5-(4-trifluorophenyl)-10,15,20-tris(4-N,N,N-trimethylammoniumphenyl)porphyrin (TFAP(3+)), 5,10,15,20-tetrakis(4-N,N,N-trimethylammoniumphenyl)porphyrin (TMAP(4+)) and 5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin (TMPyP(4+)) was investigated on Candida albicans cells. These cationic porphyrins are effective photosensitizers, producing a ~5 log decrease of cell survival when the cultures are incubated with 5 μM photosensitizer and irradiated for 30 min with visible light. Studies under anoxic conditions indicated that oxygen is necessary for the mechanism of action of photodynamic inactivation of this yeast. Furthermore, photoinactivation of C. albicans cells was negligible in the presence of 100 mM azide ion, whereas the photocytotoxicity induced by these porphyrins increased in D(2)O. In contrast, the addition of 100 mM mannitol produced a negligible effect on the cellular phototoxicity. On the other hand, in vitro direct observation of singlet molecular oxygen, O(2)((1)Δ(g)) phosphorescence at 1270 nm was analyzed using C. albicans in D(2)O. A shorter lifetime of O(2)((1)Δ(g)) was found in yeast cellular suspensions. These cationic porphyrins bind strongly to C. albicans cells and the O(2)((1)Δ(g)) generated inside the cells is rapidly quenched by the biomolecules of the cellular microenvironment. Therefore, the results indicate that these cationic porphyrins appear to act as photosensitizers mainly via the intermediacy of O(2)((1)Δ(g)). This journal is © The Royal Society of Chemistry and Owner Societies 2011

Sensitivity of Candida albicans to essential oils: are they an alternative to antifungal agents?

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Bona, E; Cantamessa, S; Pavan, M; Novello, G; Massa, N; Rocchetti, A; Berta, G; Gamalero, E

2016-12-01

Candida albicans is an important opportunistic pathogen, responsible for the majority of yeast infections in humans. Essential oils, extracted from aromatic plants, are well-known antimicrobial agents, characterized by a broad spectrum of activities, including antifungal properties. The aim of this work was to assess the sensitivity of 30 different vaginal isolated strains of C. albicans to 12 essential oils, compared to the three main used drugs (clotrimazole, fluconazole and itraconazole). Thirty strains of C. albicans were isolated from vaginal swab on CHROMagar ™ Candida. The agar disc diffusion method was employed to determine the sensitivity to the essential oils. The antifungal activity of the essential oils and antifungal drugs (clotrimazole, itraconazole and fluconazole) were investigated using a microdilution method. Transmission and scanning electron microscopy analyses were performed to get a deep inside on cellular damages. Mint, basil, lavender, tea tree oil, winter savory and oregano essential oils inhibited both the growth and the activity of C. albicans more efficiently than clotrimazole. Damages induced by essential oils at the cellular level were stronger than those caused by clotrimazole. Candida albicans is more sensitive to different essential oils compared to the main used drugs. Moreover, the essential oil affected mainly the cell wall and the membranes of the yeast. The results of this work support the research for new alternatives or complementary therapies against vaginal candidiasis. © 2016 The Society for Applied Microbiology.

Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR

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Romaniuk, Joseph A. H.; Cegelski, Lynette

2015-01-01

The ability to characterize bacterial cell-wall composition and structure is crucial to understanding the function of the bacterial cell wall, determining drug modes of action and developing new-generation therapeutics. Solid-state NMR has emerged as a powerful tool to quantify chemical composition and to map cell-wall architecture in bacteria and plants, even in the context of unperturbed intact whole cells. In this review, we discuss solid-state NMR approaches to define peptidoglycan composition and to characterize the modes of action of old and new antibiotics, focusing on examples in Staphylococcus aureus. We provide perspectives regarding the selected NMR strategies as we describe the exciting and still-developing cell-wall and whole-cell NMR toolkit. We also discuss specific discoveries regarding the modes of action of vancomycin analogues, including oritavancin, and briefly address the reconsideration of the killing action of β-lactam antibiotics. In such chemical genetics approaches, there is still much to be learned from perturbations enacted by cell-wall assembly inhibitors, and solid-state NMR approaches are poised to address questions of cell-wall composition and assembly in S. aureus and other organisms. PMID:26370936

Effect of Piper betle and Brucea javanica on the Differential Expression of Hyphal Wall Protein (HWP1 in Non-Candida albicans Candida (NCAC Species

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Wan Himratul Aznita Wan Harun

2013-01-01

Full Text Available The study aimed to identify the HWP1 gene in non-Candida albicans Candida species and the differential expression of HWP1 following treatment with Piper betle and Brucea javanica aqueous extracts. All candidal suspensions were standardized to 1×106 cells/mL. The suspension was incubated overnight at 37 °C (C. parapsilosis, 35°C. Candidal cells were treated with each respective extract at 1, 3, and 6 mg/mL for 24 h. The total RNA was extracted and reverse transcription-polymerase chain reaction was carried out with a specific primer of HWP1. HWP1 mRNAs were only detected in C. albicans, C. parapsilosis, and C. tropicalis. Exposing the cells to the aqueous extracts has affected the expression of HWP1 transcripts. C. albicans, C. parapsilosis, and C. tropicalis have demonstrated different intensity of mRNA. Compared to P. betle, B. javanica demonstrated a higher suppression on the transcript levels of HWP1 in all samples. HWP1 was not detected in C. albicans following the treatment of B. javanica at 1 mg/mL. In contrast, C. parapsilosis and C. tropicalis were shown to have HWP1 regulation. However, the expression levels were reduced upon the addition of higher concentration of B. javanica extract. P. betle and B. javanica have potential to be developed as oral health product.

Human vaginal epithelial cells augment autophagy marker genes in response to Candida albicans infection.

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Shroff, Ankit; Sequeira, Roicy; Reddy, Kudumula Venkata Rami

2017-04-01

Autophagy plays an important role in clearance of intracellular pathogens. However, no information is available on its involvement in vaginal infections such as vulvo-vaginal candidiasis (VVC). VVC is intimately associated with the immune status of the human vaginal epithelial cells (VECs). The objective of our study is to decipher if autophagy process is involved during Candida albicans infection of VECs. In this study, C. albicans infection system was established using human VEC line (VK2/E6E7). Infection-induced change in the expression of autophagy markers like LC3 and LAMP-1 were analyzed by RT-PCR, q-PCR, Western blot, immunofluorescence and transmission electron microscopy (TEM) studies were carried out to ascertain the localization of autophagosomes. Multiplex ELISA was carried out to determine the cytokine profiles. Analysis of LC3 and LAMP-1 expression at mRNA and protein levels at different time points revealed up-regulation of these markers 6 hours post C. albicans infection. LC3 and LAMP-1 puncti were observed in infected VECs after 12 hours. TEM studies showed C. albicans entrapped in autophagosomes. Cytokines-TNF-α and IL-1β were up-regulated in culture supernatants of VECs at 12 hours post-infection. The results suggest that C. albicans invasion led to the activation of autophagy as a host defense mechanism of VECs. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans.

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Douglas, Lois M; Konopka, James B

2016-03-01

Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans.

Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans

Science.gov (United States)

Douglas, Lois M.; Konopka, James. B.

2017-01-01

Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans. PMID:26920878

Plant cell wall polysaccharide analysis during cell elongation

DEFF Research Database (Denmark)

Guo, Xiaoyuan

Plant cell walls are complex structures whose composition and architecture are important to various cellular activities. Plant cell elongation requires a high level of rearrangement of the cell wall polymers to enable cell expansion. However, the cell wall polysaccharides dynamics during plant cell...... elongation is poorly understood. This PhD project aims to elucidate the cell wall compositional and structural change during cell elongation by using Comprehensive Microarray Polymer Profiling (CoMPP), microscopic techniques and molecular modifications of cell wall polysaccharide. Developing cotton fibre......, pea and Arabidopsis thaliana were selected as research models to investigate different types of cell elongation, developmental elongation and tropism elongation. A set of comprehensive analysis covering 4 cotton species and 11 time points suggests that non-cellulosic polysaccharides contribute...

PKC signaling regulates drug resistance of the fungal pathogen Candida albicans via circuitry comprised of Mkc1, calcineurin, and Hsp90.

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Shantelle L LaFayette

2010-08-01

Full Text Available Fungal pathogens exploit diverse mechanisms to survive exposure to antifungal drugs. This poses concern given the limited number of clinically useful antifungals and the growing population of immunocompromised individuals vulnerable to life-threatening fungal infection. To identify molecules that abrogate resistance to the most widely deployed class of antifungals, the azoles, we conducted a screen of 1,280 pharmacologically active compounds. Three out of seven hits that abolished azole resistance of a resistant mutant of the model yeast Saccharomyces cerevisiae and a clinical isolate of the leading human fungal pathogen Candida albicans were inhibitors of protein kinase C (PKC, which regulates cell wall integrity during growth, morphogenesis, and response to cell wall stress. Pharmacological or genetic impairment of Pkc1 conferred hypersensitivity to multiple drugs that target synthesis of the key cell membrane sterol ergosterol, including azoles, allylamines, and morpholines. Pkc1 enabled survival of cell membrane stress at least in part via the mitogen activated protein kinase (MAPK cascade in both species, though through distinct downstream effectors. Strikingly, inhibition of Pkc1 phenocopied inhibition of the molecular chaperone Hsp90 or its client protein calcineurin. PKC signaling was required for calcineurin activation in response to drug exposure in S. cerevisiae. In contrast, Pkc1 and calcineurin independently regulate drug resistance via a common target in C. albicans. We identified an additional level of regulatory control in the C. albicans circuitry linking PKC signaling, Hsp90, and calcineurin as genetic reduction of Hsp90 led to depletion of the terminal MAPK, Mkc1. Deletion of C. albicans PKC1 rendered fungistatic ergosterol biosynthesis inhibitors fungicidal and attenuated virulence in a murine model of systemic candidiasis. This work establishes a new role for PKC signaling in drug resistance, novel circuitry through which

Purification and germination of Candida albicans and Candida dubliniensis chlamydospores cultured in liquid media.

LENUS (Irish Health Repository)

Citiulo, Francesco

2009-10-01

Candida albicans and Candida dubliniensis are the only Candida sp. that have been observed to produce chlamydospores. The function of these large, thick-walled cells is currently unknown. In this report, we describe the production and purification of chlamydospores from these species in defined liquid media. Staining with the fluorescent dye FUN-1 indicated that chlamydospores are metabolically active cells, but that metabolic activity is undetectable in chlamydospores that are >30 days old. However, 5-15-day-old chlamydospores could be induced to produce daughter chlamydospores, blastospores, pseudohyphae and true hyphae depending on the incubation conditions used. Chlamydospores that were preinduced to germinate were also observed to escape from murine macrophages following phagocytosis, suggesting that these structures may be viable in vivo. Mycelium-attached and purified chlamydospores rapidly lost their viability in water and when subjected to dry stress, suggesting that they are unlikely to act as long-term storage structures. Instead, our data suggest that chlamydospores represent an alternative specialized form of growth by C. albicans and C. dubliniensis.

Reconstitution of a secondary cell wall in a secondary cell wall-deficient Arabidopsis mutant.

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Sakamoto, Shingo; Mitsuda, Nobutaka

2015-02-01

The secondary cell wall constitutes a rigid frame of cells in plant tissues where rigidity is required. Deposition of the secondary cell wall in fiber cells contributes to the production of wood in woody plants. The secondary cell wall is assembled through co-operative activities of many enzymes, and their gene expression is precisely regulated by a pyramidal cascade of transcription factors. Deposition of a transmuted secondary cell wall in empty fiber cells by expressing selected gene(s) in this cascade has not been attempted previously. In this proof-of-concept study, we expressed chimeric activators of 24 transcription factors that are preferentially expressed in the stem, in empty fiber cells of the Arabidopsis nst1-1 nst3-1 double mutant, which lacks a secondary cell wall in fiber cells, under the control of the NST3 promoter. The chimeric activators of MYB46, SND2 and ANAC075, as well as NST3, reconstituted a secondary cell wall with different characteristics from those of the wild type in terms of its composition. The transgenic lines expressing the SND2 or ANAC075 chimeric activator showed increased glucose and xylose, and lower lignin content, whereas the transgenic line expressing the MYB46 chimeric activator showed increased mannose content. The expression profile of downstream genes in each transgenic line was also different from that of the wild type. This study proposed a new screening strategy to identify factors of secondary wall formation and also suggested the potential of the artificially reconstituted secondary cell walls as a novel raw material for production of bioethanol and other chemicals. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

Silver colloidal nanoparticles: antifungal effect against adhered cells and biofilms of Candida albicans and Candida glabrata.

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Monteiro, D R; Gorup, L F; Silva, S; Negri, M; de Camargo, E R; Oliveira, R; Barbosa, D B; Henriques, M

2011-08-01

The aim of this study was to evaluate the effect of silver nanoparticles (SN) against Candida albicans and Candida glabrata adhered cells and biofilms. SN (average diameter 5 nm) were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. Minimal inhibitory concentration (MIC) tests were performed for C. albicans (n = 2) and C. glabrata (n = 2) grown in suspension following the Clinical Laboratory Standards Institute microbroth dilution method. SN were applied to adhered cells (2 h) or biofilms (48 h) and after 24 h of contact their effect was assessed by enumeration of colony forming units (CFUs) and quantification of total biomass (by crystal violet staining). The MIC results showed that SN were fungicidal against all strains tested at very low concentrations (0.4-3.3 μg ml(-1)). Furthermore, SN were more effective in reducing biofilm biomass when applied to adhered cells (2 h) than to pre-formed biofilms (48 h), with the exception of C. glabrata ATCC, which in both cases showed a reduction ∼90%. Regarding cell viability, SN were highly effective on adhered C. glabrata and respective biofilms. On C. albicans the effect was not so evident but there was also a reduction in the number of viable biofilm cells. In summary, SN may have the potential to be an effective alternative to conventional antifungal agents for future therapies in Candida-associated denture stomatitis.

Streptococcus mutans Can Modulate Biofilm Formation and Attenuate the Virulence of Candida albicans

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Barbosa, Júnia Oliveira; Rossoni, Rodnei Dennis; Vilela, Simone Furgeri Godinho; de Alvarenga, Janaína Araújo; Velloso, Marisol dos Santos; Prata, Márcia Cristina de Azevedo; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos

2016-01-01

Streptococcus mutans and Candida albicans are found together in the oral biofilms on dental surfaces, but little is known about the ecological interactions between these species. Here, we studied the effects of S. mutans UA159 on the growth and pathogencity of C. albicans. Initially, the effects of S. mutans on the biofilm formation and morphogenesis of C. albicans were tested in vitro. Next, we investigate the influence of S. mutans on pathogenicity of C. albicans using in vivo host models, in which the experimental candidiasis was induced in G. mellonella larvae and analyzed by survival curves, C. albicans count in hemolymph, and quantification of hyphae in the host tissues. In all the tests, we evaluated the direct effects of S. mutans cells, as well as the indirect effects of the subproducts secreted by this microorganism using a bacterial culture filtrate. The in vitro analysis showed that S. mutans cells favored biofilm formation by C. albicans. However, a reduction in biofilm viable cells and inhibition of hyphal growth was observed when C. albicans was in contact with the S. mutans culture filtrate. In the in vivo study, injection of S. mutans cells or S. mutans culture filtrate into G. mellonella larvae infected with C. albicans increased the survival of these animals. Furthermore, a reduction in hyphal formation was observed in larval tissues when C. albicans was associated with S. mutans culture filtrate. These findings suggest that S. mutans can secrete subproducts capable to inhibit the biofilm formation, morphogenesis and pathogenicity of C. albicans, attenuating the experimental candidiasis in G. mellonella model. PMID:26934196

Effect of whey goat milk kefir on hydrophobicity of E. coli O157:H7, S. typhi bacteria and C. albicans

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Dedi Fardiaz

2012-03-01

Full Text Available The hydrophobicity of bacteria. was determined using BATH (Bacteria adhesion to hydrocarbon test. All bacteria showed that 0,9 ml n-octane exposure gave a positive response and indicating that E. coli O157:H7 was categorized as moderate hydrophobic bacteria,  while S.  typhi  and C. albicans were catagorized as  highly hydrophobic bacteria. Goat Milk Kefir increased hydrophobicity of E.  coli O157:H7 by 24.40, however, decreased hydrophobicity of S. typhi by 47.56  and C. albicans by 70.14 percent, respectively. This finding showed that one of the inhibition mechanism may be caused by  an interaction  of  organic acid and peptide  compounds with cell membrane, in which hydrophobic sites of component  modified the hydrophobicity of the bacteria cell surface. The hydrophobicity modification in bacterial  cell wall might result inhibition of adhetion bacteria at cell host. Key words : Enterophatogenic bacteria, hidrophobisitas bacteria

Association Mapping of Cell Wall Synthesis Regulatory Genes and Cell Wall Quality in Switchgrass

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Bartley, Laura [Univ. of Oklahoma, Norman, OK (United States). Dept. of Microbiology and Plant Biology; Wu, Y. [Oklahoma State Univ., Stillwater, OK (United States); Zhu, L. [Oklahoma State Univ., Stillwater, OK (United States); Brummer, E. C. [Noble Foundation, Ardmore, OK (United States); Saha, M. [Noble Foundation, Ardmore, OK (United States)

2016-05-31

Inefficient conversion of biomass to biofuels is one of the main barriers for biofuel production from such materials. Approximately half of polysaccharides in biomass remain unused by typical biochemical conversion methods. Conversion efficiency is influenced by the composition and structure of cell walls of biomass. Grasses such as wheat, maize, and rice, as well as dedicated perennial bioenergy crops, like switchgrass, make up ~55% of biomass that can be produced in the United States. Grass cell walls have a different composition and patterning compared with dicotyledonous plants, including the well-studied model plant, Arabidopsis. This project identified genetic determinants of cell wall composition in grasses using both naturally occurring genetic variation of switchgrass and gene network reconstruction and functional assays in rice. In addition, the project linked functional data in rice and other species to switchgrass improvement efforts through curation of the most abundant class of regulators in the switchgrass genome. Characterizing natural diversity of switchgrass for variation in cell wall composition and properties, also known as quality, provides an unbiased avenue for identifying biologically viable diversity in switchgrass cell walls. To characterizing natural diversity, this project generated cell wall composition and enzymatic deconstruction data for ~450 genotypes of the Switchgrass Southern Association Collection (SSAC), a diverse collection composed of 36 switchgrass accessions from the southern U.S. distribution of switchgrass. Comparing these data with other measures of cell wall quality for the same samples demonstrated the complementary nature of the diverse characterization platforms now being used for biomass characterization. Association of the composition data with ~3.2K single nucleotide variant markers identified six significant single nucleotide variant markers co-associated with digestibility and another compositional trait. These

The metabolic response of Candida albicans to farnesol under hyphae-inducing conditions.

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Han, Ting-Li; Cannon, Richard D; Villas-Bôas, Silas G

2012-12-01

Farnesol is a quorum-sensing molecule (QSM) produced, and sensed, by the polymorphic fungus, Candida albicans. This cell-to-cell communication molecule is known to suppress the hyphal formation of C. albicans at high cell density. Despite many studies investigating the signalling mechanisms by which QSMs influence the morphogenesis of C. albicans, the downstream metabolic effect of these signalling pathways in response to farnesol-mediated morphogenesis remains obscure. Here, we have used metabolomics to investigate the metabolic response of C. albicans upon exposure to farnesol under hyphae-inducing conditions. We have found a general up-regulation of central carbon metabolic pathways when hyphal formation was suppressed by farnesol evidenced by a considerably larger number of central carbon metabolic intermediates detected under this condition at an overall lower intracellular level. By combining the metabolic profiles from farnesol-exposed cells with previous metabolomics data for C. albicans undergoing morphogenesis, we have identified several metabolic pathways that are likely to be associated with the morphogenetic process of C. albicans, as well as metabolic pathways such as those involved in lipid metabolism that appeared to be specifically affected by farnesol. Therefore, our results provide important new insights into the metabolic role of farnesol in C. albicans metabolism. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Nicotine Enhances Interspecies Relationship between Streptococcus mutans and Candida albicans.

Science.gov (United States)

Liu, Shiyu; Qiu, Wei; Zhang, Keke; Zhou, Xuedong; Ren, Biao; He, Jinzhi; Xu, Xin; Cheng, Lei; Li, Mingyun

2017-01-01

Streptococcus mutans and Candida albicans are common microorganisms in the human oral cavity. The synergistic relationship between these two species has been deeply explored in many studies. In the present study, the effect of alkaloid nicotine on the interspecies between S. mutans and C. albicans is explored. We developed a dual-species biofilm model and studied biofilm biomass, biofilm structure, synthesis of extracellular polysaccharides (EPS), and expression of glucosyltransferases (Gtfs). Biofilm formation and bacterial and fungal cell numbers in dual-species biofilms increased in the presence of nicotine. More C. albicans cells were present in the dual-species biofilms in the nicotine-treated groups as determined by scanning electron microscopy. The synthesis of EPS was increased by 1 mg/ml of nicotine as detected by confocal laser scanning microscopy. The result of qRT-PCR showed gtfs expression was upregulated when 1 mg/ml of nicotine was used. We speculate that nicotine promoted the growth of S. mutans , and more S. mutans cells attracted more C. albicans cells due to the interaction between two species. Since S. mutans and C. albicans are putative pathogens for dental caries, the enhancement of the synergistic relationship by nicotine may contribute to caries development in smokers.

Saponins of Trifolium spp. Aerial Parts as Modulators of Candida Albicans Virulence Attributes

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Aleksandra Budzyńska

2014-07-01

Full Text Available The aim was to provide the insight into the biology of C. albicans influenced by undescribed yet properties of saponin-rich (80%–98% fractions (SAPFs, isolated from extracts of Trifolium alexandrinum, T. incarnatum, T. resupinatum var. resupinatum aerial parts. Their concentrations below 0.5 mg/mL were arbitrarily considered as subMICs for C. albicans ATCC 10231 and were further used. SAPFs affected yeast enzymatic activity, lowered tolerance to the oxidative stress, to the osmotic stress and to the action of the cell wall disrupting agent. In their presence, germ tubes formation was significantly and irreversibly inhibited, as well as Candida invasive capacity. The evaluation of SAPFs interactions with anti-mycotics showed synergistic activity, mainly with azoles. Fluconazole MIC was lowered—susceptible C. albicans ATCC 10231 was more susceptible, and resistant C. glabrata (clinical strain become more susceptible (eightfold. Moreover, the tested samples showed no hemolytic activity and at the concentrations up to 0.5 mg/mL did not reduce viability of fibroblasts L929. This study provided the original evidence that SAPFs of Trifolium spp. aerial part exhibit significant antimicrobial activity, by reduce the expression/quantity of important Candida virulence factors and have good potential for the development of novel antifungal products supporting classic drugs.

Comparative transcript profiling of Candida albicans and Candida dubliniensis identifies SFL2, a C. albicans gene required for virulence in a reconstituted epithelial infection model.

LENUS (Irish Health Repository)

Spiering, Martin J

2010-02-01

Candida albicans and Candida dubliniensis are closely related species displaying differences in virulence and genome content, therefore providing potential opportunities to identify novel C. albicans virulence genes. C. albicans gene arrays were used for comparative analysis of global gene expression in the two species in reconstituted human oral epithelium (RHE). C. albicans (SC5314) showed upregulation of hypha-specific and virulence genes within 30 min postinoculation, coinciding with rapid induction of filamentation and increased RHE damage. C. dubliniensis (CD36) showed no detectable upregulation of hypha-specific genes, grew as yeast, and caused limited RHE damage. Several genes absent or highly divergent in C. dubliniensis were upregulated in C. albicans. One such gene, SFL2 (orf19.3969), encoding a putative heat shock factor, was deleted in C. albicans. DeltaDeltasfl2 cells failed to filament under a range of hypha-inducing conditions and exhibited greatly reduced RHE damage, reversed by reintroduction of SFL2 into the DeltaDeltasfl2 strain. Moreover, SFL2 overexpression in C. albicans triggered hyphal morphogenesis. Although SFL2 deletion had no apparent effect on host survival in the murine model of systemic infection, DeltaDeltasfl2 strain-infected kidney tissues contained only yeast cells. These results suggest a role for SFL2 in morphogenesis and an indirect role in C. albicans pathogenesis in epithelial tissues.

Effects of 60 Cobalt ionizing radiation in morphology and metabolism of yeasts and Chlamydospore of Candida albicans

International Nuclear Information System (INIS)

Grillo, Michel R.F.; Demicheli, Marina C.; Andrade Junior, Heitor F.; Galiesteo Junior, Andres A.J.

2015-01-01

Candida albicans is a fungus responsible for 80-90% of fungal infections, as the symptoms are similar to those of systemic bacterial infections there is a difficulty for immediate diagnosis. These difficulties can lead to delays of antifungal therapy, which contributes to the high mortality rates associated with this infection. Resistance structures referred to as chlamydospores are very common in the pathogen, representing different cell types that form in response to certain genetic or environmental conditions. Recently, various antifungal agents and new therapeutic strategies have come into use, allowing the fungus to acquire a resistance to the drugs. The use of ionizing radiation has been widely employed for the production of immunogens against various parasites. In this work, we evaluate the effects of gamma radiation ( 60 Co) in yeast and chlamydospore of C. albicans with doses ranging from 320 to 10.240 Gy with Cobalt 60. Subsequently the samples were plated and after seven days, the colony forming units (CFU) told. The viability of irradiated cells were evaluated using the Janus green dye. A dose of 6000 Gy was considered ideal for the mitigation of chlamydospore and yeast. The dimorphic change mechanisms of both fungal structures were not harmed. The viability of chlamydospores remained above 70% while the yeast viability remained above 85%. By transmission electron microscopy and fluorescence microscopy may be noted cytoplasmic changes, defects in the cell wall, mitochondria, and the presence of partially preserved vesicles of both morphological forms of C. albicans. Irradiation both chlamydospore as C. albicans yeast allows the suppression of their reproduction, opening the possibility of their use in future candidate immunogens. (author)

Effects of 60 Cobalt ionizing radiation in morphology and metabolism of yeasts and Chlamydospore of Candida albicans

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Grillo, Michel R.F.; Demicheli, Marina C.; Andrade Junior, Heitor F.; Galiesteo Junior, Andres A.J., E-mail: galisteo@usp.br [Universidade de Sao Paulo (IMTSP/USP), Sao Paulo, SP (Brazil). Instituto de Medicina Tropical. Lab. de Protozoologia; Takakura, Cleusa F.H. [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Departamento de Patologia de Molestias Transmissiveis. Lab. de Patologia; Negro, Gilda M.B. del [Universidade de Sao Paulo (HCFM/USP/IMTSP/LIM-53), Sao Paulo, SP (Brazil). Hospital das Clinicas. Lab. de Micologia; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Candida albicans is a fungus responsible for 80-90% of fungal infections, as the symptoms are similar to those of systemic bacterial infections there is a difficulty for immediate diagnosis. These difficulties can lead to delays of antifungal therapy, which contributes to the high mortality rates associated with this infection. Resistance structures referred to as chlamydospores are very common in the pathogen, representing different cell types that form in response to certain genetic or environmental conditions. Recently, various antifungal agents and new therapeutic strategies have come into use, allowing the fungus to acquire a resistance to the drugs. The use of ionizing radiation has been widely employed for the production of immunogens against various parasites. In this work, we evaluate the effects of gamma radiation ({sup 60}Co) in yeast and chlamydospore of C. albicans with doses ranging from 320 to 10.240 Gy with Cobalt 60. Subsequently the samples were plated and after seven days, the colony forming units (CFU) told. The viability of irradiated cells were evaluated using the Janus green dye. A dose of 6000 Gy was considered ideal for the mitigation of chlamydospore and yeast. The dimorphic change mechanisms of both fungal structures were not harmed. The viability of chlamydospores remained above 70% while the yeast viability remained above 85%. By transmission electron microscopy and fluorescence microscopy may be noted cytoplasmic changes, defects in the cell wall, mitochondria, and the presence of partially preserved vesicles of both morphological forms of C. albicans. Irradiation both chlamydospore as C. albicans yeast allows the suppression of their reproduction, opening the possibility of their use in future candidate immunogens. (author)

The dectin-1/inflammasome pathway is responsible for the induction of protective T-helper 17 responses that discriminate between yeasts and hyphae of Candida albicans.

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Cheng, Shih-Chin; van de Veerdonk, Frank L; Lenardon, Megan; Stoffels, Monique; Plantinga, Theo; Smeekens, Sanne; Rizzetto, Lisa; Mukaremera, Liliane; Preechasuth, Kanya; Cavalieri, Duccio; Kanneganti, Thirumala Devi; van der Meer, Jos W M; Kullberg, Bart Jan; Joosten, Leo A B; Gow, Neil A R; Netea, Mihai G

2011-08-01

In the mucosa, the immune pathways discriminating between colonizing and invasive Candida, thus inducing tolerance or inflammation, are poorly understood. Th17 responses induced by Candida albicans hyphae are central for the activation of mucosal antifungal immunity. An essential step for the discrimination between yeasts and hyphae and induction of Th17 responses is the activation of the inflammasome by C. albicans hyphae and the subsequent release of active IL-1β in macrophages. Inflammasome activation in macrophages results from differences in cell-wall architecture between yeasts and hyphae and is partly mediated by the dectin-1/Syk pathway. These results define the dectin-1/inflammasome pathway as the mechanism that enables the host immune system to mount a protective Th17 response and distinguish between colonization and tissue invasion by C. albicans.

Antifungal activity of oligochitosans (short chain chitosans) against some Candida species and clinical isolates of Candida albicans: molecular weight-activity relationship.

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Kulikov, Sergey N; Lisovskaya, Svetlana A; Zelenikhin, Pavel V; Bezrodnykh, Evgeniya A; Shakirova, Diana R; Blagodatskikh, Inesa V; Tikhonov, Vladimir E

2014-03-03

A series of oligochitosans (short chain chitosans) prepared by acidic hydrolysis of chitosan and characterized by their molecular weight, polydispersity and degree of deacetylation were used to determine their anticandidal activities. This study has demonstrated that oligochitosans show a high fungistatic activity (MIC 8-512 μg/ml) against Candida species and clinical isolates of Candida albicans, which are resistant to a series of classic antibiotics. Flow cytometry analysis showed that oligochitosan possessed a high fungicidal activity as well. For the first time it was shown that even sub-MIC oligochitosan concentration suppressed the formation of C. albicans hyphal structures, cause severe cell wall alterations, and altered internal cell structure. These results indicate that oligochitosan should be considered as a possible alternative/additive to known anti-yeast agents in pharmaceutical compositions. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Disruption of Sphingolipid Biosynthesis Blocks Phagocytosis of Candida albicans.

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Fikadu G Tafesse

2015-10-01

Full Text Available The ability of phagocytes to clear pathogens is an essential attribute of the innate immune response. The role of signaling lipid molecules such as phosphoinositides is well established, but the role of membrane sphingolipids in phagocytosis is largely unknown. Using a genetic approach and small molecule inhibitors, we show that phagocytosis of Candida albicans requires an intact sphingolipid biosynthetic pathway. Blockade of serine-palmitoyltransferase (SPT and ceramide synthase-enzymes involved in sphingolipid biosynthesis- by myriocin and fumonisin B1, respectively, impaired phagocytosis by phagocytes. We used CRISPR/Cas9-mediated genome editing to generate Sptlc2-deficient DC2.4 dendritic cells, which lack serine palmitoyl transferase activity. Sptlc2-/- DC2.4 cells exhibited a stark defect in phagocytosis, were unable to bind fungal particles and failed to form a normal phagocytic cup to engulf C. albicans. Supplementing the growth media with GM1, the major ganglioside present at the cell surface, restored phagocytic activity of Sptlc2-/- DC2.4 cells. While overall membrane trafficking and endocytic pathways remained functional, Sptlc2-/- DC2.4 cells express reduced levels of the pattern recognition receptors Dectin-1 and TLR2 at the cell surface. Consistent with the in vitro data, compromised sphingolipid biosynthesis in mice sensitizes the animal to C. albicans infection. Sphingolipid biosynthesis is therefore critical for phagocytosis and in vivo clearance of C. albicans.

Induction of the immune response suppression in mice inoculated with Candida albicans.

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Valdez, J C; Mesón, D E; Sirena, A; de Petrino, S F; Eugenia, M; de Jorrat, B B; de Valdex, M G

1986-03-01

There is a controversy in respect to the immunological response (humoral or cellular) concerning the defense against Candida albicans. Candidosis would induce sub-populations of suppressor cells in the host cell-immune response. This report tries to show the effect of different doses of C. albicans (alive or heat-killed) on the expression of cell-mediated and humoral immunity. The effect upon cell immunity was determined by inoculating different lots of singeneic mice, doses of varied concentration of C. albicans and checking for delayed-type hipersensitivity (D.T.H.). D.T.H. was also controlled in syngeneic normal mice which had previously been injected with inoculated mice spleen cells. Humoral immunity was assayed by measuring the induced blastogenesis by Pokeweed Mitogen on spleen mononuclear cells with different doses of C. albicans. Results obtained show that the different doses gave origin to: Suppression of humoral and cell response (10(8) alive); Suppression of only humoral response (10(6) alive); Suppression of cell response and increase of humoral response (10(9) dead); Increase of both responses (10(8) dead).

The Candida albicans Biofilm Matrix: Composition, Structure and Function.

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Pierce, Christopher G; Vila, Taissa; Romo, Jesus A; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L

2017-03-01

A majority of infections caused by Candida albicans -the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.

Hsp90 governs echinocandin resistance in the pathogenic yeast Candida albicans via calcineurin.

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Sheena D Singh

2009-07-01

Full Text Available Candida albicans is the leading fungal pathogen of humans, causing life-threatening disease in immunocompromised individuals. Treatment of candidiasis is hampered by the limited number of antifungal drugs whose efficacy is compromised by host toxicity, fungistatic activity, and the emergence of drug resistance. We previously established that the molecular chaperone Hsp90, which regulates the form and function of diverse client proteins, potentiates resistance to the azoles in C. albicans and in the model yeast Saccharomyces cerevisiae. Genetic studies in S. cerevisiae revealed that Hsp90's role in azole resistance is to enable crucial cellular responses to the membrane stress exerted by azoles via the client protein calcineurin. Here, we demonstrate that Hsp90 governs cellular circuitry required for resistance to the only new class of antifungals to reach the clinic in decades, the echinocandins, which inhibit biosynthesis of a critical component of the fungal cell wall. Pharmacological or genetic impairment of Hsp90 function reduced tolerance of C. albicans laboratory strains and resistance of clinical isolates to the echinocandins and created a fungicidal combination. Compromising calcineurin function phenocopied compromising Hsp90 function. We established that calcineurin is an Hsp90 client protein in C. albicans: reciprocal co-immunoprecipitation validated physical interaction; Hsp90 inhibition blocked calcineurin activation; and calcineurin levels were depleted upon genetic reduction of Hsp90. The downstream effector of calcineurin, Crz1, played a partial role in mediating calcineurin-dependent stress responses activated by echinocandins. Hsp90's role in echinocandin resistance has therapeutic potential given that genetic compromise of C. albicans HSP90 expression enhanced the efficacy of an echinocandin in a murine model of disseminated candidiasis. Our results identify the first Hsp90 client protein in C. albicans, establish an entirely

A model for cell wall dissolution in mating yeast cells: polarized secretion and restricted diffusion of cell wall remodeling enzymes induces local dissolution.

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Huberman, Lori B; Murray, Andrew W

2014-01-01

Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells.

A Model for Cell Wall Dissolution in Mating Yeast Cells: Polarized Secretion and Restricted Diffusion of Cell Wall Remodeling Enzymes Induces Local Dissolution

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Huberman, Lori B.; Murray, Andrew W.

2014-01-01

Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells. PMID:25329559

Oxidative Stress Responses in the Human Fungal Pathogen, Candida albicans

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da Silva Dantas, Alessandra; Day, Alison; Ikeh, Mélanie; Kos, Iaroslava; Achan, Beatrice; Quinn, Janet

2015-01-01

Candida albicans is a major fungal pathogen of humans, causing approximately 400,000 life-threatening systemic infections world-wide each year in severely immunocompromised patients. An important fungicidal mechanism employed by innate immune cells involves the generation of toxic reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. Consequently, there is much interest in the strategies employed by C. albicans to evade the oxidative killing by macrophages and neutrophils. Our understanding of how C. albicans senses and responds to ROS has significantly increased in recent years. Key findings include the observations that hydrogen peroxide triggers the filamentation of this polymorphic fungus and that a superoxide dismutase enzyme with a novel mode of action is expressed at the cell surface of C. albicans. Furthermore, recent studies have indicated that combinations of the chemical stresses generated by phagocytes can actively prevent C. albicans oxidative stress responses through a mechanism termed the stress pathway interference. In this review, we present an up-date of our current understanding of the role and regulation of oxidative stress responses in this important human fungal pathogen. PMID:25723552

Isolation of the Cell Wall.

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Canut, Hervé; Albenne, Cécile; Jamet, Elisabeth

2017-01-01

This chapter describes a method allowing the purification of the cell wall for studying both polysaccharides and proteins. The plant primary cell wall is mainly composed of polysaccharides (90-95 % in mass) and of proteins (5-10 %). At the end of growth, specialized cells may synthesize a lignified secondary wall composed of polysaccharides (about 65 %) and lignin (about 35 %). Due to its composition, the cell wall is the cellular compartment having the highest density and this property is used for its purification. It plays critical roles during plant development and in response to environmental constraints. It is largely used in the food and textile industries as well as for the production of bioenergy. All these characteristics and uses explain why its study as a true cell compartment is of high interest. The proposed method of purification can be used for large amount of material but can also be downscaled to 500 mg of fresh material. Tools for checking the quality of the cell wall preparation, such as protein analysis and microscopy observation, are also provided.

The Role of Auxin in Cell Wall Expansion.

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Majda, Mateusz; Robert, Stéphanie

2018-03-22

Plant cells are surrounded by cell walls, which are dynamic structures displaying a strictly regulated balance between rigidity and flexibility. Walls are fairly rigid to provide support and protection, but also extensible, to allow cell growth, which is triggered by a high intracellular turgor pressure. Wall properties regulate the differential growth of the cell, resulting in a diversity of cell sizes and shapes. The plant hormone auxin is well known to stimulate cell elongation via increasing wall extensibility. Auxin participates in the regulation of cell wall properties by inducing wall loosening. Here, we review what is known on cell wall property regulation by auxin. We focus particularly on the auxin role during cell expansion linked directly to cell wall modifications. We also analyze downstream targets of transcriptional auxin signaling, which are related to the cell wall and could be linked to acid growth and the action of wall-loosening proteins. All together, this update elucidates the connection between hormonal signaling and cell wall synthesis and deposition.

The cell wall of Fusarium oxysporum

NARCIS (Netherlands)

Schoffelmeer, EAM; Klis, FM; Sietsma, JH; Cornelissen, BJC

1999-01-01

Sugar analysis of isolated cell walls from three formae speciales of Fusarium oxysporum showed that they contained not only glucose and (N-acetyl)-glucosamine, but also mannose, galactose, and uronic acids, presumably originating from cell wall glycoproteins. Cell wall glycoproteins accounted for

Characterization of the Sclerotinia sclerotiorum cell wall proteome.

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Liu, Longzhou; Free, Stephen J

2016-08-01

We used a proteomic analysis to identify cell wall proteins released from Sclerotinia sclerotiorum hyphal and sclerotial cell walls via a trifluoromethanesulfonic acid (TFMS) digestion. Cell walls from hyphae grown in Vogel's glucose medium (a synthetic medium lacking plant materials), from hyphae grown in potato dextrose broth and from sclerotia produced on potato dextrose agar were used in the analysis. Under the conditions used, TFMS digests the glycosidic linkages in the cell walls to release intact cell wall proteins. The analysis identified 24 glycosylphosphatidylinositol (GPI)-anchored cell wall proteins and 30 non-GPI-anchored cell wall proteins. We found that the cell walls contained an array of cell wall biosynthetic enzymes similar to those found in the cell walls of other fungi. When comparing the proteins in hyphal cell walls grown in potato dextrose broth with those in hyphal cell walls grown in the absence of plant material, it was found that a core group of cell wall biosynthetic proteins and some proteins associated with pathogenicity (secreted cellulases, pectin lyases, glucosidases and proteases) were expressed in both types of hyphae. The hyphae grown in potato dextrose broth contained a number of additional proteins (laccases, oxalate decarboxylase, peroxidase, polysaccharide deacetylase and several proteins unique to Sclerotinia and Botrytis) that might facilitate growth on a plant host. A comparison of the proteins in the sclerotial cell wall with the proteins in the hyphal cell wall demonstrated that sclerotia formation is not marked by a major shift in the composition of cell wall protein. We found that the S. sclerotiorum cell walls contained 11 cell wall proteins that were encoded only in Sclerotinia and Botrytis genomes. © 2015 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.

HIV-1 anti-retroviral drug effect on the C. albicans hyphal growth rate by a Bio-Cell Tracer system Efeito da droga anti-retroviral HIV-1 no crescimento de hifas de C. albicans monitoradas pelo sistema "Bio-Cell Tracer"

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Nadja Rodrigues de Melo

2006-09-01

Full Text Available Declining incidence of oropharyngeal candidosis and opportunistic infections over recent years can be attributed to the use of highly active anti-retroviral therapy (HAART. Infection with C. albicans generally involves adherence and colonization of superficial tissues. During this process, budding yeasts are able to transform to hyphae and penetrate into the deep tissue. Using the biocell tracer system, C. albicans hyphal growth was dynamically observed at the cellular level. Ritonavir was effective in the inhibition of hyphal growth with growth rate of 0.8 mum/min. This study showed the in vitro effect of HIV anti-retroviral drug on the growth rate of the C. albicans hyphae.O declínio na incidência de candidose orofaríngea e infecções oportunistas associadas a infecção pelo HIV tem sido atribuído a introdução da terapia antiretroviral combinada (HAART. Infecção por C. albicans envolve aderência e colonização da mucosa superficial. Durante este processo leveduras são capazes de transformar-se na forma de hifas e penetrar nos tecidos mais profundos. Usando o sistema "Bio-Cell Tracer", o crescimento de hifas de C. albicans foi observado dinamicamente a nível celular. Ritonavir, inibidor de protease do HIV, foi efetivo na inibição do crescimento de hifas com media de 0.8 mim/min.O presente estudo demonstrou o efeito in vitro de um agente anti-retroviral HIV sobre o crescimento de hifas de C. albicans.

Difunctional bacteriophage conjugated with photosensitizers for Candida albicans-targeting photodynamic inactivation.

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Dong, Shuai; Shi, Hongxi; Zhang, Xintong; Chen, Xi; Cao, Donghui; Mao, Chuanbin; Gao, Xiang; Wang, Li

2018-01-01

Candida albicans is the most prevalent fungal pathogen of the human microbiota, causing infections ranging from superficial infections of the skin to life-threatening systemic infections. Due to the increasing occurrence of antibiotic-resistant C. albicans strains, new approaches to control this pathogen are needed. Photodynamic inactivation is an emerging alternative to treat infections based on the interactions between visible light and photosensitisers, in which pheophorbide a (PPA) is a chlorophyll-based photosensitizer that could induce cell death after light irradiation. Due to PPA's phototoxicity and low efficiency, the main challenge is to implement photosensitizer cell targeting and attacking. In this study, PPA was conjugated with JM-phage by EDC/NHS crosslinking. UV-Vis spectra was used to determine the optimum conjugation percentages of PPA and JM-phage complex for photodynamic inactivation. After photodynamic inactivation, the efficacy of PPA-JM-phage was assessed by performing in vitro experiments, such as MTS assay, scanning electron microscopy, measurement of dysfunctional mitochondria, ROS accumulation, S cell arrest and apoptotic pathway. A single-chain variable-fragment phage (JM) with high affinity to MP65 was screened from human single-fold single-chain variable-fragment libraries and designed as a binding target for C. albicans cells. Subsequently, PPa was integrated into JM phage to generate a combined nanoscale material, which was called PPA-JM-phage. After photodynamic inactivation, the growth of C. albicans was inhibited by PPA-JM-phage and apoptosis was observed. Scanning electron microscopy analysis revealed shrinking and rupturing of C. albicans . We also found that depolarization of mitochondrial membrane potential was decreased and intracellular reactive oxygen species levels were elevated significantly in C. albicans inhibited by PPA-JM-phage. Additionally, PPA-JM-phage also lead to S-phase arrest, and metacaspase activation

Rheumatoid arthritis patients exhibit impaired Candida albicans-specific Th17 responses.

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Bishu, Shrinivas; Su, Ee Wern; Wilkerson, Erich R; Reckley, Kelly A; Jones, Donald M; McGeachy, Mandy J; Gaffen, Sarah L; Levesque, Marc C

2014-02-11

Accumulating data implicate the CD4+ T cell subset (Th17 cells) in rheumatoid arthritis (RA). IL-17 is an inflammatory cytokine that induces tumor necrosis factor (TNF)α, IL-1β and IL-6, all of which are targets of biologic therapies used to treat RA. RA patients are well documented to experience more infections than age-matched controls, and biologic therapies further increase the risk of infection. The Th17/IL-17 axis is vital for immunity to fungi, especially the commensal fungus Candida albicans. Therefore, we were prompted to examine the relationship between RA and susceptibility to C. albicans because of the increasing interest in Th17 cells and IL-17 in driving autoimmunity, and the advent of new biologics that target this pathway. We analyzed peripheral blood and saliva from 48 RA and 33 healthy control subjects. To assess C. albicans-specific Th17 responses, PBMCs were co-cultured with heat-killed C. albicans extract, and IL-17A levels in conditioned supernatants were measured by ELISA. The frequency of Th17 and Th1 cells was determined by flow cytometry. As a measure of IL-17A-mediated effector responses, we evaluated C. albicans colonization rates in the oral cavity, salivary fungicidal activity and levels of the antimicrobial peptide β-defensin 2 (BD2) in saliva. Compared to controls, PBMCs from RA subjects exhibited elevated baseline production of IL-17A (P = 0.004), although they had similar capacity to produce IL-17A in response to Th17 cell differentiating cytokines (P = 0.91). However RA PBMCs secreted less IL-17A in response to C. albicans antigens (P = 0.006). Significantly more RA patients were colonized with C. albicans in the oral cavity than healthy subjects (P = 0.02). Concomitantly, RA saliva had reduced concentrations of salivary BD2 (P = 0.02). Nonetheless, salivary fungicidal activity was preserved in RA subjects (P = 0.70). RA subjects exhibit detectable impairments in oral immune responses to C. albicans, a

A core filamentation response network in Candida albicans is restricted to eight genes.

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Ronny Martin

Full Text Available Although morphological plasticity is a central virulence trait of Candida albicans, the number of filament-associated genes and the interplay of mechanisms regulating their expression remain unknown. By correlation-based network modeling of the transcriptional response to different defined external stimuli for morphogenesis we identified a set of eight genes with highly correlated expression patterns, forming a core filamentation response. This group of genes included ALS3, ECE1, HGT2, HWP1, IHD1 and RBT1 which are known or supposed to encode for cell- wall associated proteins as well as the Rac1 guanine nucleotide exchange factor encoding gene DCK1 and the unknown function open reading frame orf19.2457. The validity of network modeling was confirmed using a dataset of advanced complexity that describes the transcriptional response of C. albicans during epithelial invasion as well as comparing our results with other previously published transcriptome studies. Although the set of core filamentation response genes was quite small, several transcriptional regulators are involved in the control of their expression, depending on the environmental condition.

Evaluation of adhesion forces of Staphylococcus aureus along the length of Candida albicans hyphae.

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Ovchinnikova, Ekaterina S; Krom, Bastiaan P; Busscher, Henk J; van der Mei, Henny C

2012-11-27

Candida albicans is a human fungal pathogen, able to cause both superficial and serious, systemic diseases and is able to switch from yeast cells to long, tube-like hyphae, depending on the prevailing environmental conditions. Both morphological forms of C. albicans are found in infected tissue, often in combination with Staphylococcus aureus. Although bacterial adhesion to the different morphologies of C. albicans has been amply studied, possible differences in staphylococcal adhesion forces along the length of C. albicans hyphae have never been determined. In this study, we aim to verify the hypothesis that the forces mediating S. aureus NCTC8325-4GFP adhesion to hyphae vary along the length of C. albicans SC5314 and MB1 hyphae, as compared with adhesion to yeast cells. C. albicans hyphae were virtually divided into a "tip" (the growing and therefore youngest part of the hyphae), a "middle" and a so-called "head" region (the yeast cell from which germination started). Adhesion forces between S. aureus NCTC8325-4GFP and the different regions of C. albicans SC5314 hyphae were measured using atomic force microscopy. Strong adhesion forces were found at the tip and middle regions of C. albicans hyphae (-4.1 nN and -4.0 nN, respectively), while much smaller adhesion forces were measured at the head region (-0.3 nN). Adhesion forces exerted by the head region were comparable with the forces arising from budding yeast cells (-0.5 nN). A similar regional dependence of the staphylococcal adhesion forces was found for the clinical isolate involved in this study, C. albicans MB1. This is the first time that differences in adhesion forces between S. aureus and different regions of C. albicans hyphae have been demonstrated on a quantitative basis, supporting the view that the head region is different from the remainder of the hyphae. Notably it can be concluded that the properties of the hyphal head region are similar to those of budding yeast cells. These novel findings

Functional duality of the cell wall.

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Latgé, Jean-Paul; Beauvais, Anne

2014-08-01

The polysaccharide cell wall is the extracellular armour of the fungal cell. Although essential in the protection of the fungal cell against aggressive external stresses, the biosynthesis of the polysaccharide core is poorly understood. For a long time it was considered that this cell wall skeleton was a fixed structure whose role was only to be sensed as non-self by the host and consequently trigger the defence response. It is now known that the cell wall polysaccharide composition and localization continuously change to adapt to their environment and that these modifications help the fungus to escape from the immune system. Moreover, cell wall polysaccharides could function as true virulence factors. Copyright © 2014 Elsevier Ltd. All rights reserved.

Diurnal Periodicity in the Supply of Cell Wall Components during Wood Cell Wall Formation

OpenAIRE

細尾, 佳宏

2012-01-01

This review summarizes recent studies on the diurnal periodicity in wood cell wall formation, with a major focus on those that we have conducted. Differences in the innermost surface of developing secondary walls of differentiating conifer tracheids can be seen from day to night Cellulose microfibrils are clearly evident during the day, and amorphous material containing abundant hemicelluloses is prevalent at night. These findings suggest a diurnal periodicity in the supply of cell wall compo...

Evaluation of cell wall preparations for proteomics: a new procedure for purifying cell walls from Arabidopsis hypocotyls

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Canut Hervé

2006-05-01

Full Text Available Abstract Background The ultimate goal of proteomic analysis of a cell compartment should be the exhaustive identification of resident proteins; excluding proteins from other cell compartments. Reaching such a goal closely depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific difficulties: (i the lack of a surrounding membrane may result in the loss of cell wall proteins (CWP during the isolation procedure, (ii polysaccharide networks of cellulose, hemicelluloses and pectins form potential traps for contaminants such as intracellular proteins. Several reported procedures to isolate cell walls for proteomic analyses led to the isolation of a high proportion (more than 50% of predicted intracellular proteins. Since isolated cell walls should hold secreted proteins, one can imagine alternative procedures to prepare cell walls containing a lower proportion of contaminant proteins. Results The rationales of several published procedures to isolate cell walls for proteomics were analyzed, with regard to the bioinformatic-predicted subcellular localization of the identified proteins. Critical steps were revealed: (i homogenization in low ionic strength acid buffer to retain CWP, (ii purification through increasing density cushions, (iii extensive washes with a low ionic strength acid buffer to retain CWP while removing as many cytosolic proteins as possible, and (iv absence of detergents. A new procedure was developed to prepare cell walls from etiolated hypocotyls of Arabidopsis thaliana. After salt extraction, a high proportion of proteins predicted to be secreted was released (73%, belonging to the same functional classes as proteins identified using previously described protocols. Finally, removal of intracellular proteins was obtained using detergents, but their amount represented less than 3% in mass of the total protein extract, based on protein quantification. Conclusion The

Secreted Aspartic Protease Cleavage of Candida albicans Msb2 Activates Cek1 MAPK Signaling Affecting Biofilm Formation and Oropharyngeal Candidiasis

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Chadha, Sonia; Tati, Swetha; Conti, Heather R.; Hube, Bernhard; Cullen, Paul J.; Edgerton, Mira

2012-01-01

Perception of external stimuli and generation of an appropriate response are crucial for host colonization by pathogens. In pathogenic fungi, mitogen activated protein kinase (MAPK) pathways regulate dimorphism, biofilm/mat formation, and virulence. Signaling mucins, characterized by a heavily glycosylated extracellular domain, a transmembrane domain, and a small cytoplasmic domain, are known to regulate various signaling pathways. In Candida albicans, the mucin Msb2 regulates the Cek1 MAPK pathway. We show here that Msb2 is localized to the yeast cell wall and is further enriched on hyphal surfaces. A msb2Δ/Δ strain formed normal hyphae but had biofilm defects. Cek1 (but not Mkc1) phosphorylation was absent in the msb2Δ/Δ mutant. The extracellular domain of Msb2 was shed in cells exposed to elevated temperature and carbon source limitation, concomitant with germination and Cek1 phosphorylation. Msb2 shedding occurred differentially in cells grown planktonically or on solid surfaces in the presence of cell wall and osmotic stressors. We further show that Msb2 shedding and Cek1 phosphorylation were inhibited by addition of Pepstatin A (PA), a selective inhibitor of aspartic proteases (Saps). Analysis of combinations of Sap protease mutants identified a sap8Δ/Δ mutant with reduced MAPK signaling along with defects in biofilm formation, thereby suggesting that Sap8 potentially serves as a major regulator of Msb2 processing. We further show that loss of either Msb2 (msb2Δ/Δ) or Sap8 (sap8Δ/Δ) resulted in higher C. albicans surface β-glucan exposure and msb2Δ/Δ showed attenuated virulence in a murine model of oral candidiasis. Thus, Sap-mediated proteolytic cleavage of Msb2 is required for activation of the Cek1 MAPK pathway in response to environmental cues including those that induce germination. Inhibition of Msb2 processing at the level of Saps may provide a means of attenuating MAPK signaling and reducing C. albicans virulence. PMID:23139737

Photodynamic inactivation of Candida albicans sensitized by tri- and tetra-cationic porphyrin derivatives.

Science.gov (United States)

Cormick, M Paula; Alvarez, M Gabriela; Rovera, Marisa; Durantini, Edgardo N

2009-04-01

The photodynamic action of 5-(4-trifluorophenyl)-10,15,20-tris(4-trimethylammoniumphenyl)porphyrin iodide (TFAP(3+)) and 5,10,15,20-tetra(4-N,N,N-trimethylammonium phenyl)porphyrin p-tosylate (TMAP(4+)) has been studied in vitro on Candida albicans. The results of these cationic porphyrins were compared with those of 5,10,15,20-tetra(4-sulphonatophenyl)porphyrin (TPPS(4-)), which characterizes an anionic sensitizer. In vitro investigations show that these cationic porphyrins are rapidly bound to C. albicans cells, reaching a value of approximately 1.4 nmol/10(6) cells, when the cellular suspensions were incubated with 5 microM sensitizer for 30 min. In contrast, TPPS(4-) is poorly uptaken by yeast cells. The fluorescence spectra of these sensitizers into the cells confirm this behaviour. The amount of porphyrin binds to cells is dependent on both sensitizer concentrations (1-5 microM) and cells densities (10(6)-10(8) cells/mL). Photosensitized inactivation of C. albicans cellular suspensions increases with sensitizer concentration, causing a approximately 5 log decrease of cell survival, when the cultures are treated with 5 microM of cationic porphyrin and irradiated for 30 min. However, the photocytotoxicity decreases with an increase in the cell density, according to its low binding to cells. Under these conditions, the photodynamic activity of TFAP(3+) is quite similar to that produced by TMAP(4+), whereas no important inactivation effect was found for TPPS(4)(-). The high photodynamic activity of cationic porphyrins was confirmed by growth delay experiments. Thus, C. albicans cell growth was not detected in the presence of 5 microM TFAP(3+). Photodynamic inactivation capacities of these sensitizers were also evaluated on C. albicans cells growing in colonies on agar surfaces. Cationic porphyrins produce a growth delay of C. albicans colonies and viability of cells was not observed after 3 h irradiation, indicating a complete inactivation of yeast cells

Arabidopsis Regenerating Protoplast: A Powerful Model System for Combining the Proteomics of Cell Wall Proteins and the Visualization of Cell Wall Dynamics

Science.gov (United States)

Yokoyama, Ryusuke; Kuki, Hiroaki; Kuroha, Takeshi; Nishitani, Kazuhiko

2016-01-01

The development of a range of sub-proteomic approaches to the plant cell wall has identified many of the cell wall proteins. However, it remains difficult to elucidate the precise biological role of each protein and the cell wall dynamics driven by their actions. The plant protoplast provides an excellent means not only for characterizing cell wall proteins, but also for visualizing the dynamics of cell wall regeneration, during which cell wall proteins are secreted. It therefore offers a unique opportunity to investigate the de novo construction process of the cell wall. This review deals with sub-proteomic approaches to the plant cell wall through the use of protoplasts, a methodology that will provide the basis for further exploration of cell wall proteins and cell wall dynamics. PMID:28248244

Cell wall heterogeneity in root development of Arabidopsis

Directory of Open Access Journals (Sweden)

Marc Somssich

2016-08-01

Full Text Available Plant cell walls provide stability and protection to plant cells. During growth and development the composition of cell walls changes, but provides enough strength to withstand the turgor of the cells. Hence, cell walls are highly flexible and diverse in nature. These characteristics are important during root growth, as plant roots consist of radial patterns of cells that have diverse functions and that are at different developmental stages along the growth axis. Young stem cell daughters undergo a series of rapid cell divisions, during which new cell walls are formed that are highly dynamic, and that support rapid anisotropic cell expansion. Once the cells have differentiated, the walls of specific cell types need to comply with and support different cell functions. For example, a newly formed root hair needs to be able to break through the surrounding soil, while endodermal cells modify their walls at distinct positions to form Casparian strips between them. Hence, the cell walls are modified and rebuilt while cells transit through different developmental stages. In addition, the cell walls of roots readjust to their environment to support growth and to maximize nutrient uptake. Many of these modifications are likely driven by different developmental and stress signalling pathways. However, our understanding of how such pathways affect cell wall modifications and what enzymes are involved remain largely unknown. In this review we aim to compile data linking cell wall content and re-modelling to developmental stages of root cells, and dissect how root cell walls respond to certain environmental changes.

Baicalin prevents Candida albicans infections via increasing its apoptosis rate

International Nuclear Information System (INIS)

Yang, Shulong; Fu, Yingyuan; Wu, Xiuzhen; Zhou, Zhixing; Xu, Jing; Zeng, Xiaoping; Kuang, Nanzhen; Zeng, Yurong

2014-01-01

Highlights: • Baicalin increases the ratio of the G0/G1 stages and C. albicans apoptosis. • Baicalin decreases the proliferation index of C. albicans. • Baicalin inhibits the biosynthesis of DNA, RNA and protein in C. albicans. • Baicalin depresses Succinate Dehydrogenase and Ca 2+ –Mg 2+ ATPase in C. albicans. • Baicalin increases the endocytic free Ca 2+ concentration in C. albicans. - Abstract: Background: These experiments were employed to explore the mechanisms underlying baicalin action on Candida albicans. Methodology and principal findings: We detected the baicalin inhibition effects on three isotope-labeled precursors of 3 H-UdR, 3 H-TdR and 3 H-leucine incorporation into C. albicans using the isotope incorporation technology. The activities of Succinate Dehydrogenase (SDH), cytochrome oxidase (CCO) and Ca 2+ –Mg 2+ ATPase, cytosolic Ca 2+ concentration, the cell cycle and apoptosis, as well as the ultrastructure of C.albicans were also tested. We found that baicalin inhibited 3 H-UdR, 3 H-TdR and 3 H-leucine incorporation into C.albicans (P < 0.005). The activities of the SDH and Ca 2+ –Mg 2+ ATPase of C.albicans in baicalin groups were lower than those in control group (P < 0.05). Ca 2+ concentrations of C. albicans in baicalin groups were much higher than those in control group (P < 0.05). The ratio of C.albicans at the G0/G1 stage increased in baicalin groups in dose dependent manner (P < 0.01). There were a significant differences in the apoptosis rate of C.albicans between baicalin and control groups (P < 0.01). After 12–48 h incubation with baicalin (1 mg/ml), C. albicans shown to be markedly damaged under transmission electron micrographs. Innovation and significance: Baicalin can increase the apoptosis rate of C. albicans. These effects of Baicalin may involved in its inhibiting the activities of the SDH and Ca 2+ –Mg 2+ ATPase, increasing cytosolic Ca 2+ content and damaging the ultrastructure of C. albicans

Central Role for Dermal Fibroblasts in Skin Model Protection against Candida albicans.

Science.gov (United States)

Kühbacher, Andreas; Henkel, Helena; Stevens, Philip; Grumaz, Christian; Finkelmeier, Doris; Burger-Kentischer, Anke; Sohn, Kai; Rupp, Steffen

2017-06-01

The fungal pathogen Candida albicans colonizes basically all human epithelial surfaces, including the skin. Under certain conditions, such as immunosuppression, invasion of the epithelia occurs. Not much is known about defense mechanisms against C. albicans in subepithelial layers such as the dermis. Using immune cell-supplemented 3D skin models we defined a new role for fibroblasts in the dermis and identified a minimal set of cell types for skin protection against C. albicans invasion. Dual RNA sequencing of individual host cell populations and C. albicans revealed that dermal invasion is directly impeded by dermal fibroblasts. They are able to integrate signals from the pathogen and CD4+ T cells and shift toward an antimicrobial phenotype with broad specificity that is dependent on Toll-like receptor 2 and interleukin 1β. These results highlight a central function of dermal fibroblasts for skin protection, opening new possibilities for treatment of infectious diseases. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Glycoprotein component of plant cell walls

International Nuclear Information System (INIS)

Cooper, J.B.; Chen, J.A.; Varner, J.E.

1984-01-01

The primary wall surrounding most dicotyledonous plant cells contains a hydroxyproline-rich glycoprotein (HRGP) component named extensin. A small group of glycopeptides solubilized from isolated cell walls by proteolysis contained a repeated pentapeptide glycosylated by tri- and tetraarabinosides linked to hydroxyproline and, by galactose, linked to serine. Recently, two complementary approaches to this problem have provided results which greatly increase the understanding of wall extensin. In this paper the authors describe what is known about the structure of soluble extensin secreted into the walls of the carrot root cells

Detecting Candida albicans in human milk.

Science.gov (United States)

Morrill, Jimi Francis; Pappagianis, Demosthenes; Heinig, M Jane; Lönnerdal, Bo; Dewey, Kathryn G

2003-01-01

Procedures for diagnosis of mammary candidosis, including laboratory confirmation, are not well defined. Lactoferrin present in human milk can inhibit growth of Candida albicans, thereby limiting the ability to detect yeast infections. The inhibitory effect of various lactoferrin concentrations on the growth of C. albicans in whole human milk was studied. The addition of iron to the milk led to a two- to threefold increase in cell counts when milk contained 3.0 mg of lactoferrin/ml and markedly reduced the likelihood of false-negative culture results. This method may provide the necessary objective support needed for diagnosis of mammary candidosis.

30 years of battling the cell wall.

Science.gov (United States)

Latgé, J P

2017-01-01

In Aspergillus fumigatus, like in other pathogenic fungi, the cell wall is essential for fungal growth as well as for resisting environmental stresses such as phagocytic killing. Most of the chemical analyses undertaken on the cell wall of A. fumigatus are focused on the mycelial cell wall because it is the vegetative stage of the fungus. However, the cell walls of the mycelium and conidium (which is the infective propagule) are different especially at the level of the surface layer, which plays a significant role in the interaction between A. fumigatus conidia and phagocytic cells of the immune system. In spite of the essential function of the cell wall in fungal life, progresses have been extremely slow in the understanding of biosynthesis as well in the identification of the key host responses against the cell wall components. A major difficulty is the fact that the composition and structural organization of the cell wall is not immutably set and is constantly reshuffled depending on the environmental conditions. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

2003 Plant Cell Walls Gordon Conference

Energy Technology Data Exchange (ETDEWEB)

Daniel J. Cosgrove

2004-09-21

This conference will address recent progress in many aspects of cell wall biology. Molecular, genetic, and genomic approaches are yielding major advances in our understanding of the composition, synthesis, and architecture of plant cell walls and their dynamics during growth, and are identifying the genes that encode the machinery needed to make their biogenesis possible. This meeting will bring together international scientists from academia, industry and government labs to share the latest breakthroughs and perspectives on polysaccharide biosynthesis, wood formation, wall modification, expansion and interaction with other organisms, and genomic & evolutionary analyses of wall-related genes, as well as to discuss recent ''nanotechnological'' advances that take wall analysis to the level of a single cell.

Beyond Candida albicans: Mechanisms of immunity to non-albicans Candida species

Science.gov (United States)

Whibley, Natasha; Gaffen, Sarah L.

2015-01-01

The fungal genus Candida encompasses numerous species that inhabit a variety of hosts, either as commensal microbes and/or pathogens. Candida species are a major cause of fungal infections, yet to date there are no vaccines against Candida or indeed any other fungal pathogen. Our knowledge of immunity to Candida mainly comes from studies on C. albicans, the most frequent species associated with disease. However, non-albicans Candida (NAC) species also cause disease and their prevalence is increasing. Although research into immunity to NAC species is still at an early stage, it is becoming apparent that immunity to C. albicans differs in important ways from non-albicans species, with important implications for treatment, therapy and predicted demographic susceptibility. This review will discuss the current understanding of immunity to NAC species in the context of immunity to C. albicans, and highlight as-yet unanswered questions. PMID:26276374

Candida krusei and Candida glabrata reduce the filamentation of Candida albicans by downregulating expression of HWP1 gene.

Science.gov (United States)

de Barros, Patrícia Pimentel; Freire, Fernanda; Rossoni, Rodnei Dennis; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

2017-07-01

Pathogenicity of Candida albicans is associated with its capacity switch from yeast-like to hyphal growth. The hyphal form is capable to penetrate the epithelial surfaces and to damage the host tissues. Therefore, many investigations have focused on mechanisms that control the morphological transitions of C. albicans. Recently, certain studies have showed that non-albicans Candida species can reduce the capacity of C. albicans to form biofilms and to develop candidiasis in animal models. Then, the objective of this study was to evaluate the effects of Candida krusei and Candida glabrata on the morphogenesis of C. albicans. Firstly, the capacity of reference and clinical strains of C. albicans in forming hyphae was tested in vitro. After that, the expression of HWP1 (hyphal wall protein 1) gene was determined by quantitative real-time PCR (polymerase chain reaction) assay. For both reference and clinical strains, a significant inhibition of the hyphae formation was observed when C. albicans was incubated in the presence of C. krusei or C. glabrata compared to the control group composed only by C. albicans. In addition, the culture mixed of C. albicans-C. krusei or C. albicans-C. glabrata reduced significantly the expression of HWP1 gene of C. albicans in relation to single cultures of this specie. In both filamentation and gene expression assays, C. krusei showed the higher inhibitory activity on the morphogenesis of C. albicans compared to C. glabrata. C. krusei and C. glabrata are capable to reduce the filamentation of C. albicans and consequently decrease the expression of the HWP1 gene.

Salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA.

Science.gov (United States)

Gao, Qiuqiang; Liou, Liang-Chun; Ren, Qun; Bao, Xiaoming; Zhang, Zhaojie

2014-03-03

The yeast cell wall plays an important role in maintaining cell morphology, cell integrity and response to environmental stresses. Here, we report that salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA (ρ 0 ). Upon salt treatment, the cell wall is thickened, broken and becomes more sensitive to the cell wall-perturbing agent sodium dodecyl sulfate (SDS). Also, SCW11 mRNA levels are elevated in ρ 0 cells. Deletion of SCW11 significantly decreases the sensitivity of ρ 0 cells to SDS after salt treatment, while overexpression of SCW11 results in higher sensitivity. In addition, salt stress in ρ 0 cells induces high levels of reactive oxygen species (ROS), which further damages the cell wall, causing cells to become more sensitive towards the cell wall-perturbing agent.

Genetic Control of Conventional and Pheromone-Stimulated Biofilm Formation in Candida albicans

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Lin, Ching-Hsuan; Kabrawala, Shail; Fox, Emily P.; Nobile, Clarissa J.; Johnson, Alexander D.; Bennett, Richard J.

2013-01-01

Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced – under a specialized set of conditions – to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such “pheromone-stimulated” biofilms with that of “conventional” C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 196 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former. PMID:23637598

Anaerobic bacteria grow within Candida albicans biofilms and induce biofilm formation in suspension cultures.

Science.gov (United States)

Fox, Emily P; Cowley, Elise S; Nobile, Clarissa J; Hartooni, Nairi; Newman, Dianne K; Johnson, Alexander D

2014-10-20

The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival. Copyright © 2014 Elsevier Ltd. All rights reserved.

Baicalin prevents Candida albicans infections via increasing its apoptosis rate

Energy Technology Data Exchange (ETDEWEB)

Yang, Shulong; Fu, Yingyuan, E-mail: yingyuanfu@126.com; Wu, Xiuzhen; Zhou, Zhixing; Xu, Jing; Zeng, Xiaoping; Kuang, Nanzhen; Zeng, Yurong

2014-08-15

Highlights: • Baicalin increases the ratio of the G0/G1 stages and C. albicans apoptosis. • Baicalin decreases the proliferation index of C. albicans. • Baicalin inhibits the biosynthesis of DNA, RNA and protein in C. albicans. • Baicalin depresses Succinate Dehydrogenase and Ca{sup 2+}–Mg{sup 2+} ATPase in C. albicans. • Baicalin increases the endocytic free Ca{sup 2+} concentration in C. albicans. - Abstract: Background: These experiments were employed to explore the mechanisms underlying baicalin action on Candida albicans. Methodology and principal findings: We detected the baicalin inhibition effects on three isotope-labeled precursors of {sup 3}H-UdR, {sup 3}H-TdR and {sup 3}H-leucine incorporation into C. albicans using the isotope incorporation technology. The activities of Succinate Dehydrogenase (SDH), cytochrome oxidase (CCO) and Ca{sup 2+}–Mg{sup 2+} ATPase, cytosolic Ca{sup 2+} concentration, the cell cycle and apoptosis, as well as the ultrastructure of C.albicans were also tested. We found that baicalin inhibited {sup 3}H-UdR, {sup 3}H-TdR and {sup 3}H-leucine incorporation into C.albicans (P < 0.005). The activities of the SDH and Ca{sup 2+}–Mg{sup 2+} ATPase of C.albicans in baicalin groups were lower than those in control group (P < 0.05). Ca{sup 2+} concentrations of C. albicans in baicalin groups were much higher than those in control group (P < 0.05). The ratio of C.albicans at the G0/G1 stage increased in baicalin groups in dose dependent manner (P < 0.01). There were a significant differences in the apoptosis rate of C.albicans between baicalin and control groups (P < 0.01). After 12–48 h incubation with baicalin (1 mg/ml), C. albicans shown to be markedly damaged under transmission electron micrographs. Innovation and significance: Baicalin can increase the apoptosis rate of C. albicans. These effects of Baicalin may involved in its inhibiting the activities of the SDH and Ca{sup 2+}–Mg{sup 2+} ATPase, increasing

The plant cell wall integrity maintenance mechanism--a case study of a cell wall plasma membrane signaling network.

Science.gov (United States)

Hamann, Thorsten

2015-04-01

Some of the most important functions of plant cell walls are protection against biotic/abiotic stress and structural support during growth and development. A prerequisite for plant cell walls to perform these functions is the ability to perceive different types of stimuli in both qualitative and quantitative manners and initiate appropriate responses. The responses in turn involve adaptive changes in cellular and cell wall metabolism leading to modifications in the structures originally required for perception. While our knowledge about the underlying plant mechanisms is limited, results from Saccharomyces cerevisiae suggest the cell wall integrity maintenance mechanism represents an excellent example to illustrate how the molecular mechanisms responsible for stimulus perception, signal transduction and integration can function. Here I will review the available knowledge about the yeast cell wall integrity maintenance system for illustration purposes, summarize the limited knowledge available about the corresponding plant mechanism and discuss the relevance of the plant cell wall integrity maintenance mechanism in biotic stress responses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Arabidopsis Regenerating Protoplast: A Powerful Model System for Combining the Proteomics of Cell Wall Proteins and the Visualization of Cell Wall Dynamics

OpenAIRE

Yokoyama, Ryusuke; Kuki, Hiroaki; Kuroha, Takeshi; Nishitani, Kazuhiko

2016-01-01

The development of a range of sub-proteomic approaches to the plant cell wall has identified many of the cell wall proteins. However, it remains difficult to elucidate the precise biological role of each protein and the cell wall dynamics driven by their actions. The plant protoplast provides an excellent means not only for characterizing cell wall proteins, but also for visualizing the dynamics of cell wall regeneration, during which cell wall proteins are secreted. It therefore offers a uni...

Investigation of Plant Cell Wall Properties: A Study of Contributions from the Nanoscale to the Macroscale Impacting Cell Wall Recalcitrance

Science.gov (United States)

Crowe, Jacob Dillon

Biochemical conversion of lignocellulosic biomass to fuel ethanol is one of a few challenging, yet opportune technologies that can reduce the consumption of petroleum-derived transportation fuels, while providing parallel reductions in greenhouse gas emissions. Biomass recalcitrance, or resistance to deconstruction, is a major technical challenge that limits effective conversion of biomass to fermentable sugars, often requiring a costly thermochemical pretreatment step to improve biomass deconstruction. Biomass recalcitrance is imparted largely by the secondary cell wall, a complex polymeric matrix of cell wall polysaccharides and aromatic heteropolymers, that provides structural stability to cells and enables plant upright growth. Polymers within the cell wall can vary both compositionally and structurally depending upon plant species and anatomical fraction, and have varied responses to thermochemical pretreatments. Cell wall properties impacting recalcitrance are still not well understood, and as a result, the goal of this dissertation is to investigate structural features of the cell wall contributing to recalcitrance (1) in diverse anatomical fractions of a single species, (2) in response to diverse pretreatments, and (3) resulting from genetic modification. In the first study, feedstock cell wall heterogeneity was investigated in anatomical (stem, leaf sheaths, and leaf blades) and internode fractions of switchgrass at varying tissue maturities. Lignin content was observed as the key contributor to recalcitrance in maturing stem tissues only, with non-cellulosic substituted glucuronoarabinoxylans and pectic polysaccharides contributing to cell wall recalcitrance in leaf sheath and leaf blades. Hydroxycinnamate (i.e., saponifiable p-coumarate and ferulate) content along with xylan and pectin extractability decreased with tissue maturity, suggesting lignification is only one component imparting maturity specific cell wall recalcitrance. In the second study

KRE5 Suppression Induces Cell Wall Stress and Alternative ER Stress Response Required for Maintaining Cell Wall Integrity in Candida glabrata

Science.gov (United States)

Sasaki, Masato; Ito, Fumie; Aoyama, Toshio; Sato-Okamoto, Michiyo; Takahashi-Nakaguchi, Azusa; Chibana, Hiroji; Shibata, Nobuyuki

2016-01-01

The maintenance of cell wall integrity in fungi is required for normal cell growth, division, hyphae formation, and antifungal tolerance. We observed that endoplasmic reticulum stress regulated cell wall integrity in Candida glabrata, which possesses uniquely evolved mechanisms for unfolded protein response mechanisms. Tetracycline-mediated suppression of KRE5, which encodes a predicted UDP-glucose:glycoprotein glucosyltransferase localized in the endoplasmic reticulum, significantly increased cell wall chitin content and decreased cell wall β-1,6-glucan content. KRE5 repression induced endoplasmic reticulum stress-related gene expression and MAP kinase pathway activation, including Slt2p and Hog1p phosphorylation, through the cell wall integrity signaling pathway. Moreover, the calcineurin pathway negatively regulated cell wall integrity, but not the reduction of β-1,6-glucan content. These results indicate that KRE5 is required for maintaining both endoplasmic reticulum homeostasis and cell wall integrity, and that the calcineurin pathway acts as a regulator of chitin-glucan balance in the cell wall and as an alternative mediator of endoplasmic reticulum stress in C. glabrata. PMID:27548283

Comparison of the adhesion ability of Candida albicans strains to ...

African Journals Online (AJOL)

The purpose of the present study is to investigate the ability of oral Candida albicans strains to adhere to Caco-2 and Hep-2 epithelial cells, to produce slime using Congo red and Safranin methods and to form a biofilm on polymethylmethacrylate. A total of 20 C. albicans strains were tested in the present work. The biofilm ...

Mechanochemical Polarization of Contiguous Cell Walls Shapes Plant Pavement Cells.

Science.gov (United States)

Majda, Mateusz; Grones, Peter; Sintorn, Ida-Maria; Vain, Thomas; Milani, Pascale; Krupinski, Pawel; Zagórska-Marek, Beata; Viotti, Corrado; Jönsson, Henrik; Mellerowicz, Ewa J; Hamant, Olivier; Robert, Stéphanie

2017-11-06

The epidermis of aerial plant organs is thought to be limiting for growth, because it acts as a continuous load-bearing layer, resisting tension. Leaf epidermis contains jigsaw puzzle piece-shaped pavement cells whose shape has been proposed to be a result of subcellular variations in expansion rate that induce local buckling events. Paradoxically, such local compressive buckling should not occur given the tensile stresses across the epidermis. Using computational modeling, we show that the simplest scenario to explain pavement cell shapes within an epidermis under tension must involve mechanical wall heterogeneities across and along the anticlinal pavement cell walls between adjacent cells. Combining genetics, atomic force microscopy, and immunolabeling, we demonstrate that contiguous cell walls indeed exhibit hybrid mechanochemical properties. Such biochemical wall heterogeneities precede wall bending. Altogether, this provides a possible mechanism for the generation of complex plant cell shapes. Copyright © 2017 Elsevier Inc. All rights reserved.

Oral candidiasis-adhesion of non-albicans Candida species

Directory of Open Access Journals (Sweden)

Bokor-Bratić Marija B.

2008-01-01

Full Text Available Oral candidiasis is an opportunistic infection caused primarily by Candida albicans. However, in recent years, species of non-albicans Candida have been implicated more frequently in mucosal infection. Candida species usually reside as commensal organisms and are part of normal oral microflora. Determining exactly how transformation from commensal to pathogen takes place and how it can be prevented is continuous challenge for clinical doctors. Candidal adherence to mucosal surfaces is considered as a critical initial step in the pathogenesis of oral candidiasis. Acrylic dentures, acting as reservoirs, play an important role in increasing the risk from Candida colonisation. Thus, this review discusses what is currently known about the adhesion of non-albicans Candida species of oral origin to buccal epithelial cells and denture acrylics.

Roles of membrane trafficking in plant cell wall dynamics

Directory of Open Access Journals (Sweden)

Kazuo eEbine

2015-10-01

Full Text Available The cell wall is one of the characteristic components of plant cells. The cell wall composition differs among cell types and is modified in response to various environmental conditions. To properly generate and modify the cell wall, many proteins are transported to the plasma membrane or extracellular space through membrane trafficking, which is one of the key protein transport mechanisms in eukaryotic cells. Given the diverse composition and functions of the cell wall in plants, the transport of the cell wall components and proteins that are involved in cell wall-related events could be specialized for each cell type, i.e., the machinery for cell wall biogenesis, modification, and maintenance could be transported via different trafficking pathways. In this review, we summarize the recent progress in the current understanding of the roles and mechanisms of membrane trafficking in plant cells and focus on the biogenesis and regulation of the cell wall.

Candida albicans survival and biofilm formation under starvation conditions.

Science.gov (United States)

Ning, Y; Hu, X; Ling, J; Du, Y; Liu, J; Liu, H; Peng, Z

2013-01-01

To investigate the survival and biofilm formation capacity of Candida albicans in starvation and under anaerobic conditions. Candida albicans growth and survival were monitored in vitro for up to 8 months. Fungal suspensions from late exponential, stationary and starvation phases were incubated on human dentine, polystyrene and glass slides. Scanning electron microscopy (SEM) was used to observe the process of biofilm formation. 2,3-bis(2-Methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide inner salt (XTT) reduction assay was performed to quantify the biofilm formation capability, and confocal laser scanning microscopy (CLSM) was used to study and make semi-quantitative comparisons of the ultrastructure of biofilms formed on human dentine. 'XTT bioactivity' and 'COMSTAT results' were analysed by two-way analysis of variance (ANOVA) and one-way ANOVA, respectively. Candida albicans survived for over six months. SEM demonstrated that starving C. albicans produced mature biofilms on different substrata. C. albicans of the same growth phase incubated on human dentine displayed significantly higher biofilm formation capability than on polystyrene or glass slides (P roughness coefficient and surface/volume ratio (P < 0.05). Candida albicans cells can survive and form biofilms in anaerobic and nutrient-limited conditions and may pose a treatment challenge. © 2012 International Endodontic Journal.

Plant cell wall signalling and receptor-like kinases.

Science.gov (United States)

Wolf, Sebastian

2017-02-15

Communication between the extracellular matrix and the cell interior is essential for all organisms as intrinsic and extrinsic cues have to be integrated to co-ordinate development, growth, and behaviour. This applies in particular to plants, the growth and shape of which is governed by deposition and remodelling of the cell wall, a rigid, yet dynamic, extracellular network. It is thus generally assumed that cell wall surveillance pathways exist to monitor the state of the wall and, if needed, elicit compensatory responses such as altered expression of cell wall remodelling and biosynthesis genes. Here, I highlight recent advances in the field of cell wall signalling in plants, with emphasis on the role of plasma membrane receptor-like kinase complexes. In addition, possible roles for cell wall-mediated signalling beyond the maintenance of cell wall integrity are discussed. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

A virtual infection model quantifies innate effector mechanisms and Candida albicans immune escape in human blood.

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Kerstin Hünniger

2014-02-01

Full Text Available Candida albicans bloodstream infection is increasingly frequent and can result in disseminated candidiasis associated with high mortality rates. To analyze the innate immune response against C. albicans, fungal cells were added to human whole-blood samples. After inoculation, C. albicans started to filament and predominantly associate with neutrophils, whereas only a minority of fungal cells became attached to monocytes. While many parameters of host-pathogen interaction were accessible to direct experimental quantification in the whole-blood infection assay, others were not. To overcome these limitations, we generated a virtual infection model that allowed detailed and quantitative predictions on the dynamics of host-pathogen interaction. Experimental time-resolved data were simulated using a state-based modeling approach combined with the Monte Carlo method of simulated annealing to obtain quantitative predictions on a priori unknown transition rates and to identify the main axis of antifungal immunity. Results clearly demonstrated a predominant role of neutrophils, mediated by phagocytosis and intracellular killing as well as the release of antifungal effector molecules upon activation, resulting in extracellular fungicidal activity. Both mechanisms together account for almost [Formula: see text] of C. albicans killing, clearly proving that beside being present in larger numbers than other leukocytes, neutrophils functionally dominate the immune response against C. albicans in human blood. A fraction of C. albicans cells escaped phagocytosis and remained extracellular and viable for up to four hours. This immune escape was independent of filamentation and fungal activity and not linked to exhaustion or inactivation of innate immune cells. The occurrence of C. albicans cells being resistant against phagocytosis may account for the high proportion of dissemination in C. albicans bloodstream infection. Taken together, iterative experiment

Differential effects of antifungal agents on expression of genes related to formation of Candida albicans biofilms.

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Chatzimoschou, Athanasios; Simitsopoulou, Maria; Antachopoulos, Charalampos; Walsh, Thomas J; Roilides, Emmanuel

2016-01-01

The purpose of this study was to analyse specific molecular mechanisms involved in the intrinsic resistance of C. albicans biofilms to antifungals. We investigated the transcriptional profile of three genes (BGL2, SUN41, ECE1) involved in Candida cell wall formation in response to voriconazole or anidulafungin after the production of intermediate and mature biofilms. C. albicans M61, a well-documented biofilm producer strain, was used for the development of intermediate (12 h and 18 h) and completely mature biofilms (48 h). After exposure of cells from each biofilm growth mode to voriconazole (128 and 512 mg l(-1)) or anidulafungin (0.25 and 1 mg l(-1)) for 12-24 h, total RNA samples extracted from biofilm cells were analysed by RT-PCR. The voriconazole and anidulafungin biofilm MIC was 512 and 0.5 mg l(-1) respectively. Anidulafungin caused significant up-regulation of SUN41 (3.7-9.3-fold) and BGL2 (2.2-2.8 fold) in intermediately mature biofilms; whereas, voriconazole increased gene expression in completely mature biofilms (SUN41 2.3-fold, BGL2 2.1-fold). Gene expression was primarily down-regulated by voriconazole in intermediately, but not completely mature biofilms. Both antifungals caused down-regulation of ECE1 in intermediately mature biofilms. © 2015 Blackwell Verlag GmbH.

Chemical analysis of isolated cell walls of Gram-positive bacteria and the determination of the cell wall to cell mass ratio.

NARCIS (Netherlands)

Wal, van der A.; Norde, W.; Bendinger, B.; Zehnder, A.J.B.; Lyklema, J.

1997-01-01

Cell walls of five Gram-positive bacterial strains, including four coryneforms and a Bacillus brevis strain were isolated and subsequently chemically analysed. The wall contribution to the total cell mass is calculated from a comparison of D-Lactate concentrations in hydrolysates of whole cells and

Fermentation of the endosperm cell walls of monocotyledon and dicotyledon plant species: The relationship between cell wall characteristics and fermentability

NARCIS (Netherlands)

Laar, van H.; Tamminga, S.; Williams, B.A.; Verstegen, M.W.A.

2000-01-01

Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of

Treatment of serum with supernatants from cultures of Candida albicans reduces its serum-dependent phagocytosis Tratamento de soro com sobrenadante de cultura de Candida albicans reduz a fagocitose soro-dependente

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Aderbal Antonio dos Santos

2002-01-01

Full Text Available Candida albicans is a potent activator of the complement system, and heat labile opsonins produced by activation of C3 (C3b and iC3b enhance phagocytosis of C. albicans mediated by complement receptors. In this study we treated mouse serum with supernatants from cultures of a protease producer strain of C. albicans and evaluated the ability of this serum to enhance phagocytosis of C. albicans. Cell-free supernatants from cultures of C. albicans were concentrated 5 fold and added to mouse serum for 30 min at 37ºC, before using this serum for opsonization of glutaraldehyde-fixed yeast cells. We observed that normal mouse serum increased about 3 fold the phagocytosis of C. albicans by mice peritoneal macrophages, whereas supernatant-treated serum did not increase phagocytosis. This effect of supernatants on serum was prevented by addition of pepstatin (5 µg/ ml; an inhibitor of C. albicans acid proteases to the medium. Serum treated with supernatants from cultures of a protease-deficient mutant of C. albicans also increased about 3 fold phagocytosis of the yeast. These results suggest that a protease produced by C. albicans causes proteolysis of serum opsonins, thereby reducing the phagocytosis of the yeast.Candida albicans é um potente ativador do sistema complemento, e opsoninas lábeis ao calor produzidas por ativação de C3 (C3b e iC3b aumentam a fagocitose de C. albicans mediada por receptores de complemento. Neste estudo, tratamos o soro de camundongo com sobrenadante de culturas de uma cepa de C. albicans produtora de proteases e avaliamos a capacidade deste soro reduzir a fagocitose de C. albicans. Sobrenadantes livres de células obtidos de cultura de C. albicans foram concentrados 5 vezes e adicionados ao soro de camundongo por 30 minutos a 37ºC, antes deste soro ser usado para opsonização de C. albicans na forma de levedura e fixadas em glutaraldeido. Nós observamos que soro normal aumentou 3 vezes a fagocitose de C. albicans por

Antibiofilm and Antihyphal Activities of Cedar Leaf Essential Oil, Camphor, and Fenchone Derivatives against Candida albicans

OpenAIRE

Manoharan, Ranjith Kumar; Lee, Jin-Hyung; Lee, Jintae

2017-01-01

Candida albicans can form biofilms composed of yeast, hyphal, and pseudohyphal elements, and C. albicans cells in the hyphal stage could be a virulence factor. The present study describes the chemical composition, antibiofilm, and antihyphal activities of cedar leaf essential oil (CLEO), which was found to possess remarkable antibiofilm activity against C. albicans but not to affect its planktonic cell growth. Nineteen components were identified in CLEO by gas chromatography/mass spectrometry...

Identification of Novel Cell Wall Components

Energy Technology Data Exchange (ETDEWEB)

Michelle Momany

2009-10-26

Our DOE Biosciences-funded work focused on the fungal cell wall and morphogenesis. We are especially interested in how new cell wall material is targeted to appropriate areas for polar (asymmetric) growth. Polar growth is the only way that filamentous fungi explore the environment to find suitable substrates to degrade. Work funded by this grant has resulted in a total of twenty peer-reviewed publications. In work funded by this grant, we identified nine Aspergillus nidulans temperature-sensitive (ts) mutants that fail to send out a germ tube and show a swollen cell phenotype at restrictive temperature, the swo mutants. In other organisms, a swollen cell phenotype is often associated with misdirected growth or weakened cell walls. Our work shows that several of the A. nidulans swo mutants have defects in the establishment and maintenance of polarity. Cloning of several swo genes by complementation also showed that secondary modification of proteins seems is important in polarity. We also investigated cell wall biosynthesis and branching based on leads in literature from other organisms and found that branching and nuclear division are tied and that the cell wall reorganizes during development. In our most recent work we have focused on gene expression during the shift from isotropic to polar growth. Surprisingly we found that genes previously thought to be involved only in spore formation are important in early vegetative growth as well.

Whole Saliva has a Dual Role on the Adherence of Candida albicans to Polymethylmetacrylate.

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Elguezabal, N; Maza, J L; Dorronsoro, S; Pontón, J

2008-01-01

Adhesion of Candida albicans to acrylic of dental prostheses or to salivary macromolecules adsorbed on their surface is believed to be a critical event in the development of denture stomatitis. In previous studies our group has shown that adhesion of C. albicans germ tubes to polystyrene is decreased by saliva whereas C. albicans yeast cells adhesion to the same material is enhanced. The results presented in this study confirm this dual role played by whole saliva, since it decreased the adhesion of germ tubes but increased the adhesion of yeast cells to polymethylmetacrylate (PMMA). These effects mediated by whole saliva do not seem to be related to an inhibition of the germination of C. albicans, since similar levels of filamentation were observed in presence and absence of saliva. These results may give new insights into the conflicting role of saliva in the adhesion of C. albicans to acrylic resins of dental prostheses.

The cell wall: a carbohydrate armour for the fungal cell.

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Latgé, Jean-Paul

2007-10-01

The cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched beta1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only beta1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.

Outside-in control -Does plant cell wall integrity regulate cell cycle progression?

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Gigli-Bisceglia, Nora; Hamann, Thorsten

2018-04-13

During recent years it has become accepted that plant cell walls are not inert objects surrounding all plant cells but are instead highly dynamic, plastic structures. They are involved in a large number of cell biological processes and contribute actively to plant growth, development and interaction with environment. Therefore, it is not surprising that cellular processes can control plant cell wall integrity while, simultaneously, cell wall integrity can influence cellular processes. In yeast and animal cells such a bi-directional relationship also exists between the yeast/animal extra-cellular matrices and the cell cycle. In yeast, the cell wall integrity maintenance mechanism and a dedicated plasmamembrane integrity checkpoint are mediating this relationship. Recent research has yielded insights into the mechanism controlling plant cell wall metabolism during cytokinesis. However, knowledge regarding putative regulatory pathways controlling adaptive modifications in plant cell cycle activity in response to changes in the state of the plant cell wall are not yet identified. In this review, we summarize similarities and differences in regulatory mechanisms coordinating extra cellular matrices and cell cycle activity in animal and yeast cells, discuss the available evidence supporting the existence of such a mechanism in plants and suggest that the plant cell wall integrity maintenance mechanism might also control cell cycle activity in plant cells. This article is protected by copyright. All rights reserved.

Candida albicans escapes from mouse neutrophils

DEFF Research Database (Denmark)

Ermert, David; Niemiec, Maria J; Röhm, Marc

2013-01-01

is the most widely used model organism. Neutrophils are essential immune cells to prevent opportunistic mycoses. To explore potential differences between the rodent infection model and the human host, we compared the interactions of C. albicans with neutrophil granulocytes from mice and humans. We revealed...

The Candida albicans stress response gene Stomatin-Like Protein 3 is implicated in ROS-induced apoptotic-like death of yeast phase cells.

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Karen A Conrad

Full Text Available The ubiquitous presence of SPFH (Stomatin, Prohibitin, Flotillin, HflK/HflC proteins in all domains of life suggests that their function would be conserved. However, SPFH functions are diverse with organism-specific attributes. SPFH proteins play critical roles in physiological processes such as mechanosensation and respiration. Here, we characterize the stomatin ORF19.7296/SLP3 in the opportunistic human pathogen Candida albicans. Consistent with the localization of stomatin proteins, a Slp3p-Yfp fusion protein formed visible puncta along the plasma membrane. We also visualized Slp3p within the vacuolar lumen. Slp3p primary sequence analyses identified four putative S-palmitoylation sites, which may facilitate membrane localization and are conserved features of stomatins. Plasma membrane insertion sequences are present in mammalian and nematode SPFH proteins, but are absent in Slp3p. Strikingly, Slp3p was present in yeast cells, but was absent in hyphal cells, thus categorizing it as a yeast-phase specific protein. Slp3p membrane fluorescence significantly increased in response to cellular stress caused by plasma membrane, cell wall, oxidative, or osmotic perturbants, implicating SLP3 as a general stress-response gene. A slp3Δ/Δ homozygous null mutant had no detected phenotype when slp3Δ/Δ mutants were grown in the presence of a variety of stress agents. Also, we did not observe a defect in ion accumulation, filamentation, endocytosis, vacuolar structure and function, cell wall structure, or cytoskeletal structure. However, SLP3 over-expression triggered apoptotic-like death following prolonged exposure to oxidative stress or when cells were induced to form hyphae. Our findings reveal the cellular localization of Slp3p, and for the first time associate Slp3p function with the oxidative stress response.

Molecular regulation of plant cell wall extensibility

Science.gov (United States)

Cosgrove, D. J.

1998-01-01

Gravity responses in plants often involve spatial and temporal changes in cell growth, which is regulated primarily by controlling the ability of the cell wall to extend. The wall is thought to be a cellulose-hemicellulose network embedded in a hydrated matrix of complex polysaccharides and a small amount of structural protein. The wall extends by a form of polymer creep, which is mediated by expansins, a novel group of wall-loosening proteins. Expansins were discovered during a molecular dissection of the "acid growth" behavior of cell walls. Expansin alters the rheology of plant walls in profound ways, yet its molecular mechanism of action is still uncertain. It lacks detectable hydrolytic activity against the major components of the wall, but it is able to disrupt noncovalent adhesion between wall polysaccharides. The discovery of a second family of expansins (beta-expansins) sheds light on the biological role of a major group of pollen allergens and implies that expansins have evolved for diverse developmental functions. Finally, the contribution of other processes to wall extensibility is briefly summarized.

Candida albicans infection in patients with oral squamous cell carcinoma

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Čanković Miloš

2010-01-01

Full Text Available Bacground/Aim. Systemic candidiasis in intensive care units remains an improtant problem due to antifungal resistance. Patients undergoing radiotherapy for head and neck cancer are at increased risk of developing oral candidiasis and they more frequent have prior fungi colonization. Due to identification of specific risk factors predisposing to fungal infection in order to threat such patients the aim of this study was to determine the presence of Candida species in patients with oral squamous cell carcinoma and compare it to the control subjects (patients with benign oral mucosal lesions. Methods. A total number of 30 consecutive oral cancer examined patients were included in this prospective study (24 men and 6 women with a mean age of 61.47 years, range 41-81 years. The control group consisted of 30 consecutive patients with histologically proven benign oral mucosal lesions (16 men and 14 women with a mean age of 54.53 years, range 16- 83 years. The samples for mycological examination were obtained by using sterile cotton swabs from the cancer lesion surface and in the patients of the control group from the benign mucosal lesion surface. Samples were inoculated in Sabouraud' dextrose agar. For identification purposes, Mackenzie germ tube test was performend on all isolates. Results. The prevalence of Candida was significantly higher in oral cancer patients than in control subjects (χ2 = 5.455, p = 0.020. Candida was found on nine of the 30 cancer surfaces; 5 (16.7% were identified as non-albicans Candida and 4 (13.3% as Candida albicans. In the control group, only Candida albicans was isolated from 2 (6.7% patients. In this study, no statistically significant differences in the presence of Candida species was found with respect to gender, age, smoking, alcohol consumption, wearing of dental protheses and the site of cancer lesion. Conclusion. The increased prevalence of yeasts on the surfaces of oral carcinoma indicates a need for their

Synthesis of plant cell wall oligosaccharides

DEFF Research Database (Denmark)

Clausen, Mads Hartvig

Plant cell walls are structurally complex and contain a large number of diverse carbohydrate polymers. These plant fibers are a highly valuable bio-resource and the focus of food, energy and health research. We are interested in studying the interplay of plant cell wall carbohydrates with proteins...... for characterizing protein-carbohydrate binding. The presentation will highlight chemical syntheses of plant cell wall oligosaccharides from the group and provide examples from studies of their interactions with proteins....... such as enzymes, cell surface lectins, and antibodies. However, detailed molecular level investigations of such interactions are hampered by the heterogeneity and diversity of the polymers of interest. To circumvent this, we target well-defined oligosaccharides with representative structures that can be used...

Microevolution of Candida albicans in macrophages restores filamentation in a nonfilamentous mutant.

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Anja Wartenberg

2014-12-01

Full Text Available Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of resistance against antifungals. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is nonfilamentous, as central signaling pathways linking environmental cues to hyphal formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. In addition, the evolved mutant exhibited hyper-virulence in a murine infection model and an altered cell wall composition compared to the cph1Δ/efg1Δ strain. Moreover, the transcriptional regulation of hyphae-associated, and other pathogenicity-related genes became re-responsive to environmental cues in the evolved strain. We went on to identify the causative missense mutation via whole genome- and transcriptome-sequencing: a single nucleotide exchange took place within SSN3 that encodes a component of the Cdk8 module of the Mediator complex, which links transcription factors with the general transcription machinery. This mutation was responsible for the reconnection of the hyphal growth program with environmental signals in the evolved strain and was sufficient to bypass Efg1/Cph1-dependent filamentation. These data demonstrate that even central transcriptional networks can be remodeled very quickly under appropriate selection pressure.

Difunctional bacteriophage conjugated with photosensitizers for Candida albicans-targeting photodynamic inactivation

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Dong S

2018-04-01

Full Text Available Shuai Dong,1,2 Hongxi Shi,1 Xintong Zhang,1,2 Xi Chen,1 Donghui Cao,2 Chuanbin Mao,3,4 Xiang Gao,1 Li Wang1 1Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, 2First Hospital of Jilin University, Changchun, Jilin, 3School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, China; 4Department of Chemistry and Biochemistry, Stephenson Life Science Research Center, University of Oklahoma, Norman, OK, USA Background: Candida albicans is the most prevalent fungal pathogen of the human microbiota, causing infections ranging from superficial infections of the skin to life-threatening systemic infections. Due to the increasing occurrence of antibiotic-resistant C. albicans strains, new approaches to control this pathogen are needed. Photodynamic inactivation is an emerging alternative to treat infections based on the interactions between visible light and photosensitisers, in which pheophorbide a (PPA is a chlorophyll-based photosensitizer that could induce cell death after light irradiation. Due to PPA’s phototoxicity and low efficiency, the main challenge is to implement photosensitizer cell targeting and attacking. Methods: In this study, PPA was conjugated with JM-phage by EDC/NHS crosslinking. UV-Vis spectra was used to determine the optimum conjugation percentages of PPA and JM-phage complex for photodynamic inactivation. After photodynamic inactivation, the efficacy of PPA-JM-phage was assessed by performing in vitro experiments, such as MTS assay, scanning electron microscopy, measurement of dysfunctional mitochondria, ROS accumulation, S cell arrest and apoptotic pathway.Results: A single-chain variable-fragment phage (JM with high affinity to MP65 was screened from human single-fold single-chain variable-fragment libraries and designed as a binding target for C. albicans cells. Subsequently, PPa was integrated into JM phage to generate

The Specific Nature of Plant Cell Wall Polysaccharides 1

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Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1967-01-01

Polysaccharide compositions of cell walls were assessed by quantitative analyses of the component sugars. Cell walls were hydrolyzed in 2 n trifluoroacetic acid and the liberated sugars reduced to their respective alditols. The alditols were acetylated and the resulting alditol acetates separated by gas chromatography. Quantitative assay of the alditol acetates was accomplished by electronically integrating the detector output of the gas chromatograph. Myo-inositol, introduced into the sample prior to hydrolysis, served as an internal standard. The cell wall polysaccharide compositions of plant varieties within a given species are essentially identical. However, differences in the sugar composition were observed in cell walls prepared from different species of the same as well as of different genera. The fact that the wall compositions of different varieties of the same species are the same indicates that the biosynthesis of cell wall polysaccharides is genetically regulated. The cell walls of various morphological parts (roots, hypocotyls, first internodes and primary leaves) of bean plants were each found to have a characteristic sugar composition. It was found that the cell wall sugar composition of suspension-cultured sycamore cells could be altered by growing the cells on different carbon sources. This demonstrates that the biosynthesis of cell wall polysaccharides can be manipulated without fatal consequences. PMID:16656594

Molecular mechanisms of action of herbal antifungal alkaloid berberine, in Candida albicans.

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Sanjiveeni Dhamgaye

Full Text Available Candida albicans causes superficial to systemic infections in immuno-compromised individuals. The concomitant use of fungistatic drugs and the lack of cidal drugs frequently result in strains that could withstand commonly used antifungals, and display multidrug resistance (MDR. In search of novel fungicidals, in this study, we have explored a plant alkaloid berberine (BER for its antifungal potential. For this, we screened an in-house transcription factor (TF mutant library of C. albicans strains towards their susceptibility to BER. Our screen of TF mutant strains identified a heat shock factor (HSF1, which has a central role in thermal adaptation, to be most responsive to BER treatment. Interestingly, HSF1 mutant was not only highly susceptible to BER but also displayed collateral susceptibility towards drugs targeting cell wall (CW and ergosterol biosynthesis. Notably, BER treatment alone could affect the CW integrity as was evident from the growth retardation of MAP kinase and calcineurin pathway null mutant strains and transmission electron microscopy. However, unlike BER, HSF1 effect on CW appeared to be independent of MAP kinase and Calcineurin pathway genes. Additionally, unlike hsf1 null strain, BER treatment of Candida cells resulted in dysfunctional mitochondria, which was evident from its slow growth in non-fermentative carbon source and poor labeling with mitochondrial membrane potential sensitive probe. This phenotype was reinforced with an enhanced ROS levels coinciding with the up-regulated oxidative stress genes in BER-treated cells. Together, our study not only describes the molecular mechanism of BER fungicidal activity but also unravels a new role of evolutionary conserved HSF1, in MDR of Candida.

Proper Sterol Distribution Is Required for Candida albicans Hyphal Formation and Virulence

OpenAIRE

McCourt, Paula; Liu, Hsing-Yin; Parker, Josie E.; Gallo-Ebert, Christina; Donigan, Melissa; Bata, Adam; Giordano, Caroline; Kelly, Steven L.; Nickels, Joseph T.

2016-01-01

Candida albicans is an opportunistic fungus responsible for the majority of systemic fungal infections. Multiple factors contribute to C. albicans pathogenicity. C. albicans strains lacking CaArv1 are avirulent. Arv1 has a conserved Arv1 homology domain (AHD) that has a zinc-binding domain containing two cysteine clusters. Here, we explored the role of the CaAHD and zinc-binding motif in CaArv1-dependent virulence. Overall, we found that the CaAHD was necessary but not sufficient for cells to...

At the border: the plasma membrane-cell wall continuum.

Science.gov (United States)

Liu, Zengyu; Persson, Staffan; Sánchez-Rodríguez, Clara

2015-03-01

Plant cells rely on their cell walls for directed growth and environmental adaptation. Synthesis and remodelling of the cell walls are membrane-related processes. During cell growth and exposure to external stimuli, there is a constant exchange of lipids, proteins, and other cell wall components between the cytosol and the plasma membrane/apoplast. This exchange of material and the localization of cell wall proteins at certain spots in the plasma membrane seem to rely on a particular membrane composition. In addition, sensors at the plasma membrane detect changes in the cell wall architecture, and activate cytoplasmic signalling schemes and ultimately cell wall remodelling. The apoplastic polysaccharide matrix is, on the other hand, crucial for preventing proteins diffusing uncontrollably in the membrane. Therefore, the cell wall-plasma membrane link is essential for plant development and responses to external stimuli. This review focuses on the relationship between the cell wall and plasma membrane, and its importance for plant tissue organization. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Toxicity of nalidixic acid on candida albicans, Saccharomyces cerevisiae, and Kluyveromyces lactis.

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Sobieski, R J; Brewer, A R

1976-03-01

The antibacterial drug nalidixic acid (Nal) can suppress the growth of Candida albicans at levels of the drug normally found in urine. Growth suppression increases as drug levels are increased, and Nal also causes a similar proportional inhibition of the synthesis of all cellular macromolecules. However, growth temperature (25 versus 37 C) and the divalent cations Mg(2+) and Mn(2+) can increase C. albicans resistance to Nal. Also, nitrogen depletion of Candida shows that Nal-treated and untreated cells exhibit no difference in leucine uptake during readaptation to nitrogen. In Nal-treated, nitrogen-starved cells, ribonucleic acid and deoxyribonucleic acid (DNA) biosynthesis are less affected than in unstarved Nal-treated cells, but of the two nucleic acids DNA synthesis is the most affected. Nal-resistant strains of C. albicans exhibit a slight toxicity for macromolecular synthesis. Nal treatment of a synchronized population of Saccharomyces cerevisiae results in an increase in the culture mean doubling time of, at most, 20%, but Nal causes the loss of synchronous cell division. With a synchronized population of Kluyveromyces lactis, Nal causes an increase in the mean doubling time of upwards of 300%, with synchrony of cell division being maintained. It is known that S. cerevisiae asynchronously synthesizes mitochondrial DNA during the cell cycle, whereas with K. lactis it is synchronous. Thus, with C. albicans Nal toxicity is dependent both on the dose and the physiological state of the cell. Furthermore, Nal inhibits growth of yeast with synchronous mitochondrial DNA synthesis more adversely than yeast with asynchronous mitochondrial DNA synthesis.

Cell wall-bound silicon optimizes ammonium uptake and metabolism in rice cells.

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Sheng, Huachun; Ma, Jie; Pu, Junbao; Wang, Lijun

2018-05-16

Turgor-driven plant cell growth depends on cell wall structure and mechanics. Strengthening of cell walls on the basis of an association and interaction with silicon (Si) could lead to improved nutrient uptake and optimized growth and metabolism in rice (Oryza sativa). However, the structural basis and physiological mechanisms of nutrient uptake and metabolism optimization under Si assistance remain obscure. Single-cell level biophysical measurements, including in situ non-invasive micro-testing (NMT) of NH4+ ion fluxes, atomic force microscopy (AFM) of cell walls, and electrolyte leakage and membrane potential, as well as whole-cell proteomics using isobaric tags for relative and absolute quantification (iTRAQ), were performed. The altered cell wall structure increases the uptake rate of the main nutrient NH4+ in Si-accumulating cells, whereas the rate is only half in Si-deprived counterparts. Rigid cell walls enhanced by a wall-bound form of Si as the structural basis stabilize cell membranes. This, in turn, optimizes nutrient uptake of the cells in the same growth phase without any requirement for up-regulation of transmembrane ammonium transporters. Optimization of cellular nutrient acquisition strategies can substantially improve performance in terms of growth, metabolism and stress resistance.

Effect of ferrocene-substituted porphyrin RL-91 on Candida albicans biofilm formation.

Science.gov (United States)

Lippert, Rainer; Vojnovic, Sandra; Mitrovic, Aleksandra; Jux, Norbert; Ivanović-Burmazović, Ivana; Vasiljevic, Branka; Stankovic, Nada

2014-08-01

Ferrocene-substituted porphyrin RL-91 exhibits antifungal activity against opportune human pathogen Candida albicans. RL-91 efficiently inhibits growth of both planktonic C. albicans cells and cells within biofilms without photoactivation. The minimal inhibitory concentration for plankton form (PMIC) was established to be 100 μg/mL and the same concentration killed 80% of sessile cells in the mature biofilm (SMIC80). Furthermore PMIC of RL-91 efficiently prevents C. albicans biofilm formation. RL-91 is cytotoxic for human fibroblasts in vitro in concentration of 10 μg/mL, however it does not cause hemolysis in concentrations of up to 50 μg/mL. These findings open possibility for application of RL-91 as an antifungal agent for external antibiofilm treatment of medical devices as well as a scaffold for further development of porphyrin based systemic antifungals. Copyright © 2014 Elsevier Ltd. All rights reserved.

On-Off Switches for Secondary Cell Wall Biosynthesis

Institute of Scientific and Technical Information of China (English)

Huan-Zhong Wang; Richard A.Dixon

2012-01-01

Secondary cell walls provide plants with rigidity and strength to support their body weight and ensure water and nutrient transport.They also provide textiles,timber,and potentially second-generation biofuels for human use.Genes responsible for synthesis of the different cell wall components,namely cellulose,hemicelluloses,and lignin,are coordinately expressed and under transcriptional regulation.In the past several years,cell wall-related NAC and MYB transcription factors have been intensively investigated in different species and shown to be master switches of secondary cell wall biosynthesis.Positive and negative regulators,which function upstream of NAC master switches,have also been identified in different plant tissues.Further elucidation of the regulatory mechanisms of cell wall synthesis will facilitate the engineering of plant feedstocks suitable for biofuel production.

Candida albicans infection of Caenorhabditis elegans induces antifungal immune defenses.

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Read Pukkila-Worley

2011-06-01

Full Text Available Candida albicans yeast cells are found in the intestine of most humans, yet this opportunist can invade host tissues and cause life-threatening infections in susceptible individuals. To better understand the host factors that underlie susceptibility to candidiasis, we developed a new model to study antifungal innate immunity. We demonstrate that the yeast form of C. albicans establishes an intestinal infection in Caenorhabditis elegans, whereas heat-killed yeast are avirulent. Genome-wide, transcription-profiling analysis of C. elegans infected with C. albicans yeast showed that exposure to C. albicans stimulated a rapid host response involving 313 genes (124 upregulated and 189 downregulated, ~1.6% of the genome many of which encode antimicrobial, secreted or detoxification proteins. Interestingly, the host genes affected by C. albicans exposure overlapped only to a small extent with the distinct transcriptional responses to the pathogenic bacteria Pseudomonas aeruginosa or Staphylococcus aureus, indicating that there is a high degree of immune specificity toward different bacterial species and C. albicans. Furthermore, genes induced by P. aeruginosa and S. aureus were strongly over-represented among the genes downregulated during C. albicans infection, suggesting that in response to fungal pathogens, nematodes selectively repress the transcription of antibacterial immune effectors. A similar phenomenon is well known in the plant immune response, but has not been described previously in metazoans. Finally, 56% of the genes induced by live C. albicans were also upregulated by heat-killed yeast. These data suggest that a large part of the transcriptional response to C. albicans is mediated through "pattern recognition," an ancient immune surveillance mechanism able to detect conserved microbial molecules (so-called pathogen-associated molecular patterns or PAMPs. This study provides new information on the evolution and regulation of the innate

A Structurally Specialized Uniform Wall Layer is Essential for Constructing Wall Ingrowth Papillae in Transfer Cells

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Xia, Xue; Zhang, Hui-Ming; Offler, Christina E.; Patrick, John W.

2017-01-01

Transfer cells are characterized by wall labyrinths with either a flange or reticulate architecture. A literature survey established that reticulate wall ingrowth papillae ubiquitously arise from a modified component of their wall labyrinth, termed the uniform wall layer; a structure absent from flange transfer cells. This finding sparked an investigation of the deposition characteristics and role of the uniform wall layer using a Vicia faba cotyledon culture system. On transfer of cotyledons to culture, their adaxial epidermal cells spontaneously trans-differentiate to a reticulate architecture comparable to their abaxial epidermal transfer cell counterparts formed in planta. Uniform wall layer construction commenced once adaxial epidermal cell expansion had ceased to overlay the original outer periclinal wall on its inner surface. In contrast to the dense ring-like lattice of cellulose microfibrils in the original primary wall, the uniform wall layer was characterized by a sparsely dispersed array of linear cellulose microfibrils. A re-modeled cortical microtubule array exerted no influence on uniform wall layer formation or on its cellulose microfibril organization. Surprisingly, formation of the uniform wall layer was not dependent upon depositing a cellulose scaffold. In contrast, uniform wall cellulose microfibrils were essential precursors for constructing wall ingrowth papillae. On converging to form wall ingrowth papillae, the cellulose microfibril diameters increased 3-fold. This event correlated with up-regulated differential, and transfer-cell specific, expression of VfCesA3B while transcript levels of other cellulose biosynthetic-related genes linked with primary wall construction were substantially down-regulated. PMID:29259611

Metabolic response of Candida albicans to phenylethyl alcohol under hyphae-inducing conditions.

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Han, Ting-Li; Tumanov, Sergey; Cannon, Richard D; Villas-Boas, Silas G

2013-01-01

Phenylethyl alcohol was one of the first quorum sensing molecules (QSMs) identified in C. albicans. This extracellular signalling molecule inhibits the hyphal formation of C. albicans at high cell density. Little is known, however, about the underlying mechanisms by which this QSM regulates the morphological switches of C. albicans. Therefore, we have applied metabolomics and isotope labelling experiments to investigate the metabolic changes that occur in C. albicans in response to phenylethyl alcohol under defined hyphae-inducing conditions. Our results showed a global upregulation of central carbon metabolism when hyphal development was suppressed by phenylethyl alcohol. By comparing the metabolic changes in response to phenylethyl alcohol to our previous metabolomic studies, we were able to short-list 7 metabolic pathways from central carbon metabolism that appear to be associated with C. albicans morphogenesis. Furthermore, isotope-labelling data showed that phenylethyl alcohol is indeed taken up and catabolised by yeast cells. Isotope-labelled carbon atoms were found in the majority of amino acids as well as in lactate and glyoxylate. However, isotope-labelled carbon atoms from phenylethyl alcohol accumulated mainly in the pyridine ring of NAD(+)/NADH and NADP(-/)NADPH molecules, showing that these nucleotides were the main products of phenylethyl alcohol catabolism. Interestingly, two metabolic pathways where these nucleotides play an important role, nitrogen metabolism and nicotinate/nicotinamide metabolism, were also short-listed through our previous metabolomics works as metabolic pathways likely to be closely associated with C. albicans morphogenesis.

Hyphal formation of Candida albicans is controlled by electron transfer system

International Nuclear Information System (INIS)

Watanabe, Toshihiko; Ogasawara, Ayako; Mikami, Takeshi; Matsumoto, Tatsuji

2006-01-01

Most Candida albicans cells cultured in RPMI1640 medium at 37 deg. C grow in hyphal form in aerobic conditions, but they grow in yeast form in anaerobic conditions. The hyphal growth of C. albicans was inhibited in glucose-deficient conditions. Malonic acid, an inhibitor of succinate dehydrogenase, enhanced the yeast proliferation of C. albicans, indicating that the hyphal-formation signal was derived from the glycolysis system and the signal was transmitted to the electron transfer system via the citric acid cycle. Thenoyl trifluoro acetone (TTFA), an inhibitor of the signal transmission between complex II and Co Q, significantly inhibited the hyphal growth of C. albicans. Antimycin, KCN, and oligomycin, inhibitors of complex III, IV, and V, respectively, did not inhibit the hyphal growth of C. albicans. The production of mRNAs for the hyphal formation signal was completely inhibited in anaerobic conditions. These results indicate that the electron transfer system functions upstream of the RAS1 signal pathway and activates the expression of the hyphal formation signal. Since the electron transfer system is inactivated in anaerobic conditions, C. albicans grew in yeast form in this condition

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

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Orlean, Peter

2012-01-01

The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of β1,3- and β1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, β1,3- and β1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. PMID:23135325

Regulation of plant cells, cell walls and development by mechanical signals

Energy Technology Data Exchange (ETDEWEB)

Meyerowitz, Elliot M. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

2016-06-14

The overall goal of the revised scope of work for the final year of funding was to characterize cell wall biosynthesis in developing cotyledons and in the shoot apical meristem of Arabidopsis thaliana, as a way of learning about developmental control of cell wall biosynthesis in plants, and interactions between cell wall biosynthesis and the microtubule cytoskeleton. The proposed work had two parts – to look at the effect of mutation in the SPIRAL2 gene on microtubule organization and reorganization, and to thoroughly characterize the glycosyltransferase genes expressed in shoot apical meristems by RNA-seq experiments, by in situ hybridization of the RNAs expressed in the meristem, and by antibody staining of the products of the glycosyltransferases in meristems. Both parts were completed; the spiral2 mutant was found to speed microtubule reorientation after ablation of adjacent cells, supporting our hypothesis that reorganization correlates with microtubule severing, the rate of which is increased by the mutation. The glycosyltransferase characterization was completed and published as Yang et al. (2016). Among the new things learned was that primary cell wall biosynthesis is strongly controlled both by cell type, and by stage of cell cycle, implying not only that different, even adjacent, cells can have different sugar linkages in their (nonshared) walls, but also that a surprisingly large proportion of glycosyltransferases is regulated in the cell cycle, and therefore that the cell cycle regulates wall maturation to a degree previously unrecognized.

The transcription factor Rap1p is required for tolerance to cell-wall perturbing agents and for cell-wall maintenance in Saccharomyces cerevisiae.

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Azad, Gajendra Kumar; Singh, Vikash; Baranwal, Shivani; Thakare, Mayur Jankiram; Tomar, Raghuvir S

2015-01-02

Yeast repressor activator protein (Rap1p) is involved in genomic stability and transcriptional regulation. We explored the function of Rap1p in yeast physiology using Rap1p truncation mutants. Our results revealed that the N-terminal truncation of Rap1p (Rap1ΔN) leads to hypersensitivity towards elevated temperature and cell-wall perturbing agents. Cell wall analysis showed an increase in the chitin and glucan content in Rap1ΔN cells as compared with wild type cells. Accordingly, mutant cells had a twofold thicker cell wall, as observed by electron microscopy. Furthermore, Rap1ΔN cells had increased levels of phosphorylated Slt2p, a MAP kinase of the cell wall integrity pathway. Mutant cells also had elevated levels of cell wall integrity response transcripts. Taken together, our findings suggest a connection between Rap1p and cell wall homeostasis. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Mechanosensation Dynamically Coordinates Polar Growth and Cell Wall Assembly to Promote Cell Survival.

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Davì, Valeria; Tanimoto, Hirokazu; Ershov, Dmitry; Haupt, Armin; De Belly, Henry; Le Borgne, Rémi; Couturier, Etienne; Boudaoud, Arezki; Minc, Nicolas

2018-04-23

How growing cells cope with size expansion while ensuring mechanical integrity is not known. In walled cells, such as those of microbes and plants, growth and viability are both supported by a thin and rigid encasing cell wall (CW). We deciphered the dynamic mechanisms controlling wall surface assembly during cell growth, using a sub-resolution microscopy approach to monitor CW thickness in live rod-shaped fission yeast cells. We found that polar cell growth yielded wall thinning and that thickness negatively influenced growth. Thickness at growing tips exhibited a fluctuating behavior with thickening phases followed by thinning phases, indicative of a delayed feedback promoting thickness homeostasis. This feedback was mediated by mechanosensing through the CW integrity pathway, which probes strain in the wall to adjust synthase localization and activity to surface growth. Mutants defective in thickness homeostasis lysed by rupturing the wall, demonstrating its pivotal role for walled cell survival. Copyright © 2018 Elsevier Inc. All rights reserved.

Candida albicans mannans mediate Streptococcus mutans exoenzyme GtfB binding to modulate cross-kingdom biofilm development in vivo.

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Hwang, Geelsu; Liu, Yuan; Kim, Dongyeop; Li, Yong; Krysan, Damian J; Koo, Hyun

2017-06-01

Candida albicans is frequently detected with heavy infection by Streptococcus mutans in plaque-biofilms from children with early-childhood caries (ECC). This cross-kingdom biofilm contains an extensive matrix of extracellular α-glucans that is produced by an exoenzyme (GtfB) secreted by S. mutans. Here, we report that mannans located on the outer surface of C. albicans cell-wall mediates GtfB binding, enhancing glucan-matrix production and modulating bacterial-fungal association within biofilms formed in vivo. Using single-molecule atomic force microscopy, we determined that GtfB binds with remarkable affinity to mannans and to the C. albicans surface, forming a highly stable and strong bond (1-2 nN). However, GtfB binding properties to C. albicans was compromised in strains defective in O-mannan (pmt4ΔΔ) or N-mannan outer chain (och1ΔΔ). In particular, the binding strength of GtfB on och1ΔΔ strain was severely disrupted (>3-fold reduction vs. parental strain). In turn, the GtfB amount on the fungal surface was significantly reduced, and the ability of C. albicans mutant strains to develop mixed-species biofilms with S. mutans was impaired. This phenotype was independent of hyphae or established fungal-biofilm regulators (EFG1, BCR1). Notably, the mechanical stability of the defective biofilms was weakened, resulting in near complete biomass removal by shear forces. In addition, these in vitro findings were confirmed in vivo using a rodent biofilm model. Specifically, we observed that C. albicans och1ΔΔ was unable to form cross-kingdom biofilms on the tooth surface of rats co-infected with S. mutans. Likewise, co-infection with S. mutans defective in GtfB was also incapable of forming mixed-species biofilms. Taken together, the data support a mechanism whereby S. mutans-secreted GtfB binds to the mannan layer of C. albicans to promote extracellular matrix formation and their co-existence within biofilms. Enhanced understanding of GtfB-Candida interactions

Antibiofilm and Antihyphal Activities of Cedar Leaf Essential Oil, Camphor, and Fenchone Derivatives against Candida albicans

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Ranjith Kumar Manoharan

2017-08-01

Full Text Available Candida albicans can form biofilms composed of yeast, hyphal, and pseudohyphal elements, and C. albicans cells in the hyphal stage could be a virulence factor. The present study describes the chemical composition, antibiofilm, and antihyphal activities of cedar leaf essential oil (CLEO, which was found to possess remarkable antibiofilm activity against C. albicans but not to affect its planktonic cell growth. Nineteen components were identified in CLEO by gas chromatography/mass spectrometry, and phenolics were the main constituents. Of these, camphor, fenchone, fenchyl alcohol, α-thujone, and borneol significantly reduced C. albicans biofilm formation. Notably, treatments with CLEO, camphor, or fenchyl alcohol at 0.01% clearly inhibited hyphal formation, and this inhibition appeared to be largely responsible for their antibiofilm effects. Transcriptomic analyses indicated that camphor and fenchyl alcohol downregulated some hypha-specific and biofilm related genes (ECE1, ECE2, RBT1, and EED1. Furthermore, camphor and fenchyl alcohol reduced C. albicans virulence in a Caenorhabditis elegans nematode model. These results demonstrate CLEO, camphor, and fenchyl alcohol might be useful for controlling C. albicans infections.

Antifungal activity of phlorotannins against dermatophytes and yeasts: approaches to the mechanism of action and influence on Candida albicans virulence factor.

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Graciliana Lopes

Full Text Available In the last few decades, fungal infections, particularly nosocomial, increased all around the world. This increment stimulated the search for new antifungal agents, especially those derived from nature. Among natural products, those from marine sources have gained prominence in the last years. Purified phlorotannins extracts from three brown seaweeds (Cystoseira nodicaulis (Withering M. Roberts, Cystoseira usneoides (Linnaeus M. Roberts and Fucus spiralis Linnaeus were screened for their antifungal activity against human pathogenic yeast and filamentous fungi. The purified phlorotannins extracts from the studied seaweeds displayed fungistatic and fungicidal activity against yeast and dermatophytes, respectively, pointing to their interest as anti-dermatophyte agent. C. albicans ATCC 10231 was the most susceptible among yeast, while Epidermophyton floccosum and Trichophyton rubrum were the most susceptible among dermatophytes. Since the antifungal mechanism constitutes an important strategy for limiting the emergence of resistance to the commercially available agents, the mechanism of action of purified phlorotannins extracts was approached. C. nodicaulis and C. usneoides seem to act by affecting the ergosterol composition of the cell membrane of yeast and dermatophyte, respectively. F. spiralis influenced the dermatophyte cell wall composition by reducing the levels of chitin. Phlorotannins also seem to affect the respiratory chain function, as all of the studied species significantly increased the activity of mitochondrial dehydrogenases and increased the incorporation of rhodamine 123 by yeast cells. Phlorotannins from F. spiralis inhibited the dimorphic transition of Candida albicans, leading to the formation of pseudohyphae with diminished capacity to adhere to epithelial cells. This finding is associated with a decrease of C. albicans virulence and capacity to invade host cells and can be potentially interesting for combined antifungal

The effect of denture adhesives on Candida albicans growth in vitro.

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Sampaio-Maia, Benedita; Figueiral, Maria Helena; Sousa-Rodrigues, Patricia; Fernandes, Maria Helena; Scully, Crispian

2012-06-01

Denture-wearing favours the growth of Candida. In view of the fact that many denture wearers regularly use adhesives to enhance denture retention, stability and function, the aim of this work was to study the effect of denture adhesives on Candida albicans growth in vitro. The denture adhesives tested were Corega(®) cream, Kukident(®) cream, Novafix(®) cream, Polident(®) cream, Protefix(®) cream, Steradent(®) cream, Aderyn(®) powder, Corega(®) ultra powder, Protefix(®) powder and Corega(®) strip. C. albicans growth curves were obtained in the presence or absence of a 1% solution of the denture adhesive diluted in Sabouraud broth. Macro- and microscopic morphological changes in C. albicans were analysed, as was microbial contamination of the denture adhesive. Most of the denture adhesives studied induced morphological changes in C. albicans cells and colonies, but only two had any significant inhibitory effect on yeast growth. Kukident(®) cream markedly inhibited C. albicans growth in a concentration-dependent way, reducing the growth rate by 95%, whereas Corega(®) cream also inhibited C. albicans growth but in a non-concentration-dependent way, reducing the growth rate by 37%. In addition, denture adhesives available as powders had detectable microbial contamination. Some commercially available denture adhesives showed microbial contamination and some had significant inhibitory effect on C. albicans growth. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

A dynamical model for plant cell wall architecture formation.

NARCIS (Netherlands)

Mulder, B.M.; Emons, A.M.C.

2001-01-01

We discuss a dynamical mathematical model to explain cell wall architecture in plant cells. The highly regular textures observed in cell walls reflect the spatial organisation of the cellulose microfibrils (CMFs), the most important structural component of cell walls. Based on a geometrical theory

Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

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Kouki eYoshida

2013-10-01

Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

Candida/Candida biofilms. First description of dual-species Candida albicans/C. rugosa biofilm.

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Martins, Carlos Henrique Gomes; Pires, Regina Helena; Cunha, Aline Oliveira; Pereira, Cristiane Aparecida Martins; Singulani, Junya de Lacorte; Abrão, Fariza; Moraes, Thais de; Mendes-Giannini, Maria José Soares

2016-04-01

Denture liners have physical properties that favour plaque accumulation and colonization by Candida species, irritating oral tissues and causing denture stomatitis. To isolate and determine the incidence of oral Candida species in dental prostheses, oral swabs were collected from the dental prostheses of 66 patients. All the strains were screened for their ability to form biofilms; both monospecies and dual-species combinations were tested. Candida albicans (63 %) was the most frequently isolated microorganism; Candida tropicalis (14 %), Candida glabrata (13 %), Candida rugosa (5 %), Candida parapsilosis (3 %), and Candida krusei (2 %) were also detected. The XTT assay showed that C. albicans SC5314 possessed a biofilm-forming ability significantly higher (p biofilm was less than the total CFU of a monospecies C. albicans biofilm. In contrast to the profuse hyphae verified in monospecies C. albicans biofilms, micrographies showed that the C. albicans/non-albicans Candida biofilms consisted of sparse yeast forms and profuse budding yeast cells that generated a network. These results suggested that C. albicans and the tested Candida species could co-exist in biofilms displaying apparent antagonism. The study provide the first description of C. albicans/C. rugosa mixed biofilm. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Branched pectic galactan in phloem-sieve-element cell walls: implications for cell mechanics

DEFF Research Database (Denmark)

Torode, Thomas A.; O'Neill, Rachel E.; Marcus, Susan E.

2017-01-01

has previously been identified in garlic bulbs in which the LM26 epitope is widespread throughout most cell walls including those of phloem cells. Garlic bulb cell wall material has been used to confirm the association of the LM26 epitope with cell wall pectic rhamnogalacturonan-I (RG...

Determination of chitin content in fungal cell wall: an alternative flow cytometric method.

Science.gov (United States)

Costa-de-Oliveira, Sofia; Silva, Ana P; Miranda, Isabel M; Salvador, Alexandre; Azevedo, Maria M; Munro, Carol A; Rodrigues, Acácio G; Pina-Vaz, Cidália

2013-03-01

The conventional methods used to evaluate chitin content in fungi, such as biochemical assessment of glucosamine release after acid hydrolysis or epifluorescence microscopy, are low throughput, laborious, time-consuming, and cannot evaluate a large number of cells. We developed a flow cytometric assay, efficient, and fast, based on Calcofluor White staining to measure chitin content in yeast cells. A staining index was defined, its value was directly related to chitin amount and taking into consideration the different levels of autofluorecence. Twenty-two Candida spp. and four Cryptococcus neoformans clinical isolates with distinct susceptibility profiles to caspofungin were evaluated. Candida albicans clinical isolate SC5314, and isogenic strains with deletions in chitin synthase 3 (chs3Δ/chs3Δ) and genes encoding predicted GlycosylPhosphatidylInositol (GPI)-anchored proteins (pga31Δ/Δ and pga62Δ/Δ), were used as controls. As expected, the wild-type strain displayed a significant higher chitin content (P relationship between chitin content and antifungal drug susceptibility phenotype was found, an association was established between the paradoxical growth effect in the presence of high caspofungin concentrations and the chitin content. This novel flow cytometry protocol revealed to be a simple and reliable assay to estimate cell wall chitin content of fungi. Copyright © 2013 International Society for Advancement of Cytometry.

Deoxyribonucleic acid-deficient strains of Candida albicans.

Science.gov (United States)

Olaiya, A F; Steed, J R; Sogin, S J

1980-03-01

We analyzed a series of germ tube-negative variants isolated from Candida albicans 3153A for deoxyribonucleic acid content. As analyzed by flow microfluorometry, the deoxyribonucleic acid level in these variant strains was 50% of that of the parental strain and equivalent to that of haploid Saccharomyces cerevisiae. This finding was confirmed by comparison of survival rates when exposed to the mutagens ultraviolet light, ethyl methane sulfonate, and methyl methane sulfonate. The diameter of the variant cells as compared to the diameter of the parental 3153A strain showed a relationship similar to that of the diameters of haploid versus diploid S. cerevisiae. These results indicate that those strains may be representative of the imperfect stage of C. albicans.

Small molecule probes for plant cell wall polysaccharide imaging

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Ian eWallace

2012-05-01

Full Text Available Plant cell walls are composed of interlinked polymer networks consisting of cellulose, hemicelluloses, pectins, proteins, and lignin. The ordered deposition of these components is a dynamic process that critically affects the development and differentiation of plant cells. However, our understanding of cell wall synthesis and remodeling, as well as the diverse cell wall architectures that result from these processes, has been limited by a lack of suitable chemical probes that are compatible with live-cell imaging. In this review, we summarize the currently available molecular toolbox of probes for cell wall polysaccharide imaging in plants, with particular emphasis on recent advances in small molecule-based fluorescent probes. We also discuss the potential for further development of small molecule probes for the analysis of cell wall architecture and dynamics.

A computational approach for inferring the cell wall properties that govern guard cell dynamics.

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Woolfenden, Hugh C; Bourdais, Gildas; Kopischke, Michaela; Miedes, Eva; Molina, Antonio; Robatzek, Silke; Morris, Richard J

2017-10-01

Guard cells dynamically adjust their shape in order to regulate photosynthetic gas exchange, respiration rates and defend against pathogen entry. Cell shape changes are determined by the interplay of cell wall material properties and turgor pressure. To investigate this relationship between turgor pressure, cell wall properties and cell shape, we focused on kidney-shaped stomata and developed a biomechanical model of a guard cell pair. Treating the cell wall as a composite of the pectin-rich cell wall matrix embedded with cellulose microfibrils, we show that strong, circumferentially oriented fibres are critical for opening. We find that the opening dynamics are dictated by the mechanical stress response of the cell wall matrix, and as the turgor rises, the pectinaceous matrix stiffens. We validate these predictions with stomatal opening experiments in selected Arabidopsis cell wall mutants. Thus, using a computational framework that combines a 3D biomechanical model with parameter optimization, we demonstrate how to exploit subtle shape changes to infer cell wall material properties. Our findings reveal that proper stomatal dynamics are built on two key properties of the cell wall, namely anisotropy in the form of hoop reinforcement and strain stiffening. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd and Society for Experimental Biology.

The role of Candida albicans homologous recombination factors Rad54 and Rdh54 in DNA damage sensitivity

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White Theodore C

2011-09-01

Full Text Available Abstract Background The fungal pathogen Candida albicans is frequently seen in immune suppressed patients, and resistance to one of the most widely used antifungals, fluconazole (FLC, can evolve rapidly. In recent years it has become clear that plasticity of the Candida albicans genome contributes to drug resistance through loss of heterozygosity (LOH at resistance genes and gross chromosomal rearrangements that amplify gene copy number of resistance associated genes. This study addresses the role of the homologous recombination factors Rad54 and Rdh54 in cell growth, DNA damage and FLC resistance in Candida albicans. Results The data presented here support a role for homologous recombination in cell growth and DNA damage sensitivity, as Candida albicans rad54Δ/rad54Δ mutants were hypersensitive to MMS and menadione, and had an aberrant cell and nuclear morphology. The Candida albicans rad54Δ/rad54Δ mutant was defective in invasion of Spider agar, presumably due to the altered cellular morphology. In contrast, mutation of the related gene RDH54 did not contribute significantly to DNA damage resistance and cell growth, and deletion of either Candida albicans RAD54 or Candida albicans RDH54 did not alter FLC susceptibility. Conclusions Together, these results support a role for homologous recombination in genome stability under nondamaging conditions. The nuclear morphology defects in the rad54Δ/rad54Δ mutants show that Rad54 performs an essential role during mitotic growth and that in its absence, cells arrest in G2. The viability of the single mutant rad54Δ/rad54Δ and the inability to construct the double mutant rad54Δ/rad54Δ rdh54Δ/rdh54Δ suggests that Rdh54 can partially compensate for Rad54 during mitotic growth.

Mechanistic aspects of the photodynamic inactivation of Candida albicans induced by cationic porphyrin derivatives.

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Quiroga, Ezequiel D; Cormick, M Paula; Pons, Patricia; Alvarez, M Gabriela; Durantini, Edgardo N

2012-12-01

Photodynamic inactivation of Candida albicans produced by 5-(4-trifluorophenyl)-10,15,20-tris(4-N,N,N-trimethylammoniumphenyl)porphyrin (TFAP(3+)), 5,10,15,20-tetrakis(4-N,N,N-trimethylammoniumphenyl)porphyrin (TMAP(4+)) and 5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin (TMPyP(4+)) was investigated to obtain insight about the mechanism of cellular damage. In solution, absorption spectroscopic studies showed that these cationic porphyrins interact strongly with calf thymus DNA. The electrophoretic analysis indicated that photocleavage of DNA induced by TFAP(3+) took place after long irradiation periods (>5 h). In contrast, TMAP(4+) produced a marked reduction in DNA band after 1 h irradiation. In C. albicans, these cationic porphyrins produced a ∼3.5 log decrease in survival when the cell suspensions (10(7) cells/mL) were incubated with 5 μM photosensitizer and irradiated for 30 min with visible light (fluence 162 J/cm(2)). After this treatment, modifications of genomic DNA isolated from C. albicans cells were not found by electrophoresis. Furthermore, transmission electron microscopy showed structural changes with appearance of low density areas into the cells and irregularities in cell barriers. However, the photodamage to the cell envelope was insufficient to cause the release of intracellular biopolymers. Therefore, modifications in the cytoplasmic biomolecules and alteration in the cell barriers could be mainly involved in C. albicans photoinactivation. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Changes in Cell Wall Polysaccharides Associated With Growth 1

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Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1968-01-01

Changes in the polysaccharide composition of Phaseolus vulgaris, P. aureus, and Zea mays cell walls were studied during the first 28 days of seedling development using a gas chromatographic method for the analysis of neutral sugars. Acid hydrolysis of cell wall material from young tissues liberates rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose which collectively can account for as much as 70% of the dry weight of the wall. Mature walls in fully expanded tissues of these same plants contain less of these constituents (10%-20% of dry wt). Gross differences are observed between developmental patterns of the cell wall in the various parts of a seedling, such as root, stem, and leaf. The general patterns of wall polysaccharide composition change, however, are similar for analogous organs among the varieties of a species. Small but significant differences in the rates of change in sugar composition were detected between varieties of the same species which exhibited different growth patterns. The cell walls of species which are further removed phylogenetically exhibit even more dissimilar developmental patterns. The results demonstrate the dynamic nature of the cell wall during growth as well as the quantitative and qualitative exactness with which the biosynthesis of plant cell walls is regulated. PMID:16656862

Cell Wall Metabolism in Response to Abiotic Stress

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Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

2015-01-01

This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

Evaluation of adhesion forces of Staphylococcus aureus along the length of Candida albicans hyphae

NARCIS (Netherlands)

Ovchinnikova, E.S.; Krom, B.P.; Busscher, H.J.; van der Mei, H.C.

2012-01-01

Background Candida albicans is a human fungal pathogen, able to cause both superficial and serious, systemic diseases and is able to switch from yeast cells to long, tube-like hyphae, depending on the prevailing environmental conditions. Both morphological forms of C. albicans are found in infected

Evaluation of adhesion forces of Staphylococcus aureus along the length of Candida albicans hyphae

NARCIS (Netherlands)

Ovchinnikova, Ekaterina S.; Krom, Bastiaan P.; Busscher, Henk J.; van der Mei, Henny C.

2012-01-01

Background: Candida albicans is a human fungal pathogen, able to cause both superficial and serious, systemic diseases and is able to switch from yeast cells to long, tube-like hyphae, depending on the prevailing environmental conditions. Both morphological forms of C. albicans are found in infected

Two endogenous proteins that induce cell wall extension in plants

Science.gov (United States)

McQueen-Mason, S.; Durachko, D. M.; Cosgrove, D. J.

1992-01-01

Plant cell enlargement is regulated by wall relaxation and yielding, which is thought to be catalyzed by elusive "wall-loosening" enzymes. By employing a reconstitution approach, we found that a crude protein extract from the cell walls of growing cucumber seedlings possessed the ability to induce the extension of isolated cell walls. This activity was restricted to the growing region of the stem and could induce the extension of isolated cell walls from various dicot stems and the leaves of amaryllidaceous monocots, but was less effective on grass coleoptile walls. Endogenous and reconstituted wall extension activities showed similar sensitivities to pH, metal ions, thiol reducing agents, proteases, and boiling in methanol or water. Sequential HPLC fractionation of the active wall extract revealed two proteins with molecular masses of 29 and 30 kD associated with the activity. Each protein, by itself, could induce wall extension without detectable hydrolytic breakdown of the wall. These proteins appear to mediate "acid growth" responses of isolated walls and may catalyze plant cell wall extension by a novel biochemical mechanism.

Altered Cell Wall Plasticity Can Restrict Plant Growth under Ammonium Nutrition.

Science.gov (United States)

Podgórska, Anna; Burian, Maria; Gieczewska, Katarzyna; Ostaszewska-Bugajska, Monika; Zebrowski, Jacek; Solecka, Danuta; Szal, Bożena

2017-01-01

Plants mainly utilize inorganic forms of nitrogen (N), such as nitrate (NO 3 - ) and ammonium (NH 4 + ). However, the composition of the N source is important, because excess of NH 4 + promotes morphological disorders. Plants cultured on NH 4 + as the sole N source exhibit serious growth inhibition, commonly referred to as "ammonium toxicity syndrome." NH 4 + -mediated suppression of growth may be attributable to both repression of cell elongation and reduction of cell division. The precondition for cell enlargement is the expansion of the cell wall, which requires the loosening of the cell wall polymers. Therefore, to understand how NH 4 + nutrition may trigger growth retardation in plants, properties of their cell walls were analyzed. We found that Arabidopsis thaliana using NH 4 + as the sole N source has smaller cells with relatively thicker cell walls. Moreover, cellulose, which is the main load-bearing polysaccharide revealed a denser assembly of microfibrils. Consequently, the leaf blade tissue showed elevated tensile strength and indicated higher cell wall stiffness. These changes might be related to changes in polysaccharide and ion content of cell walls. Further, NH 4 + toxicity was associated with altered activities of cell wall modifying proteins. The lower activity and/or expression of pectin hydrolyzing enzymes and expansins might limit cell wall expansion. Additionally, the higher activity of cell wall peroxidases can lead to higher cross-linking of cell wall polymers. Overall, the NH 4 + -mediated inhibition of growth is related to a more rigid cell wall structure, which limits expansion of cells. The changes in cell wall composition were also indicated by decreased expression of Feronia , a receptor-like kinase involved in the control of cell wall extension.

Effects of nanosecond pulsed electric fields (nsPEFs) on the human fungal pathogen Candida albicans: an in vitro study

Science.gov (United States)

Guo, Jinsong; Dang, Jie; Wang, Kaile; Zhang, Jue; Fang, Jing

2018-05-01

Candida albicans is the leading human fungal pathogen that causes many life-threatening infections. Notably, the current clinical trial data indicate that Candida species shows the emerging resistance to anti-fungal drugs. The aim of this study was to evaluate the antifungal effects of nanosecond pulsed electric fields (nsPEFs) as a novel drug-free strategy in vitro. In this study, we investigated the inactivation and permeabilization effects of C. albicans under different nsPEFs exposure conditions (100 pulses, 100 ns in duration, intensities of 20, 40 kV cm‑1). Cell death was studied by annexin-V and propidium iodide staining. The changes of intracellular Ca2+ concentration after nsPEFs treatment were observed using Fluo-4 AM. Results show that C. albicans cells and biofilms were both obviously inhibited and destroyed after nsPEFs treatment. Furthermore, C. albicans cells were significantly permeabilized after nsPEFs treatment. Additionally, nsPEFs exposure led to a large amount of DNA and protein leakage. Importantly, nsPEFs induced a field strength-dependent apoptosis in C. albicans cells. Further experiments revealed that Ca2+ involved in nsPEFs induced C. albicans apoptosis. In conclusion, this proof-of-concept study provides a potential alternative drug-free strategy for killing pathogenic Candida species.

The role of wall calcium in the extension of cell walls of soybean hypocotyls

Science.gov (United States)

Virk, S. S.; Cleland, R. E.

1990-01-01

Calcium crosslinks are load-bearing bonds in soybean (Glycine max (L.) Merr.) hypocotyl cell walls, but they are not the same load-bearing bonds that are broken during acid-mediated cell elongation. This conclusion is reached by studying the relationship between wall calcium, pH and the facilitated creep of frozen-thawed soybean hypocotyl sections. Supporting data include the following observations: 1) 2-[(2-bis-[carboxymethyl]amino-5-methylphenoxy)methyl]-6-methoxy-8-bis[car boxymethyl]aminoquinoline (Quin 2) and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) caused only limited facilitated creep as compared with acid, despite removal of comparable or larger amounts of wall calcium; 2) the pH-response curves for calcium removal and acid-facilitated creep were different; 3) reversible acid-extension occurred even after removal of almost all wall calcium with Quin 2; and 4) growth of abraded sections did not involve a proportional loss of wall calcium. Removal of wall calcium, however, increased the capacity of the walls to undergo acid-facilitated creep. These data indicate that breakage of calcium crosslinks is not a major mechanism of cell-wall loosening in soybean hypocotyl tissues.

Melanocytes and melanin represent a first line of innate immunity against Candida albicans.

Science.gov (United States)

Tapia, Cecilia V; Falconer, Maryanne; Tempio, Fabián; Falcón, Felipe; López, Mercedes; Fuentes, Marisol; Alburquenque, Claudio; Amaro, José; Bucarey, Sergio A; Di Nardo, Anna

2014-07-01

Melanocytes are dendritic cells located in the skin and mucosae that synthesize melanin. Some infections induce hypo- or hyperpigmentation, which is associated with the activation of Toll-like receptors (TLRs), especially TLR4. Candida albicans is an opportunist pathogen that can switch between blastoconidia and hyphae forms; the latter is associated with invasion. Our objectives in this study were to ascertain whether C. albicans induces pigmentation in melanocytes and whether this process is dependent on TLR activation, as well as relating this with the antifungal activity of melanin as a first line of innate immunity against fungal infections. Normal human melanocytes were stimulated with C. albicans supernatants or with crude extracts of the blastoconidia or hyphae forms, and pigmentation and TLR2/TLR4 expression were measured. Expression of the melanosomal antigens Melan-A and gp100 was examined for any correlation with increased melanin levels or antifungal activity in melanocyte lysates. Melanosomal antigens were induced earlier than cell pigmentation, and hyphae induced stronger melanization than blastoconidia. Notably, when melanocytes were stimulated with crude extracts of C. albicans, the cell surface expression of TLR2/TLR4 began at 48 h post-stimulation and peaked at 72 h. At this time, blastoconidia induced both TLR2 and TLR4 expression, whereas hyphae only induced TLR4 expression. Taken together, these results suggest that melanocytes play a key role in innate immune responses against C. albicans infections by recognizing pathogenic forms of C. albicans via TLR4, resulting in increased melanin content and inhibition of infection. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oral Immunization Against Candidiasis Using Lactobacillus casei Displaying Enolase 1 from Candida albicans

OpenAIRE

Shibasaki, Seiji; Karasaki, Miki; Tafuku, Senji; Aoki, Wataru; Sewaki, Tomomitsu; Ueda, Mitsuyoshi

2014-01-01

Abstract Candidiasis is a common fungal infection that is prevalent in immunocompromised individuals. In this study, an oral vaccine against Candida albicans was developed by using the molecular display approach. Enolase 1 protein (Eno1p) of C. albicans was expressed on the Lactobacillus casei cell surface by using poly-gamma-glutamic acid synthetase complex A from Bacillus subtilis as an anchoring protein. The Eno1p-displaying L. casei cells were used to immunize mice, which were later chall...

Whole Saliva has a Dual Role on the Adherence of Candida albicans to Polymethylmetacrylate

OpenAIRE

Elguezabal, N; Maza, J.L.; Dorronsoro, S.; Pont?n, J.

2008-01-01

Adhesion of Candida albicans to acrylic of dental prostheses or to salivary macromolecules adsorbed on their surface is believed to be a critical event in the development of denture stomatitis. In previous studies our group has shown that adhesion of C. albicans germ tubes to polystyrene is decreased by saliva whereas C. albicans yeast cells adhesion to the same material is enhanced. The results presented in this study confirm this dual role played by whole saliva, since it decreased the adhe...

Antifungal effects of undecylenic acid on the biofilm formation of Candida albicans.

Science.gov (United States)

Shi, Dongmei; Zhao, Yaxin; Yan, Hongxia; Fu, Hongjun; Shen, Yongnian; Lu, Guixia; Mei, Huan; Qiu, Ying; Li, Dongmei; Liu, Weida

2016-05-01

Undecylenic acid can effectively control skin fungal infection, but the mechanism of its fungal inhibition is unclear. Hyphal growth of Candida albicans (C. albicans) and biofilm formation have been well recognized as important virulence factors for the initiation of skin infection and late development of disseminated infection. In this study, we seek to investigate antifungal mechanisms of undecylenic acid by evaluating the virulence factors of C. albicans during biofilm formation. We found that undecylenic acid inhibits biofilm formation of C. albicans effectively with optimal concentration above 3 mM. In the presence of this compound, the morphological transition from yeast to filamentous phase is abolished ultimately when the concentration of undecylenic acid is above 4 mM. Meanwhile, the cell surface is crumpled, and cells display an atrophic appearance under scanning electron microscopy even with low concentration of drug treatment. On the other hand, the drug treatment decreases the transcriptions of hydrolytic enzymes such as secreted aspartic protease, lipase, and phospholipase. Hyphal formation related genes, like HWP1, are significantly reduced in transcriptional level in drug-treated biofilm condition as well. The down-regulated profile of these genes leads to a poorly organized biofilm in undecylenic acid treated environment.

Candida albicans orf19.3727 encodes phytase activity and is essential for human tissue damage

Science.gov (United States)

Fong, Wing-Ping; Samaranayake, Lakshman Perera

2017-01-01

Candida albicans is a clinically important human fungal pathogen. We previously identified the presence of cell-associated phytase activity in C. albicans. Here, we reveal for the first time, that orf19.3727 contributes to phytase activity in C. albicans and ultimately to its virulence potency. Compared with its wild type counterpart, disruption of C. albicans orf19.3727 led to decreased phytase activity, reduced ability to form hyphae, attenuated in vitro adhesion, and reduced ability to penetrate human epithelium, which are the major virulence attributes of this yeast. Thus, orf19.3727 of C. albicans plays a key role in fungal pathogenesis. Further, our data uncover a putative novel strategy for anti-Candidal drug design through inhibition of phytase activity of this common pathogen. PMID:29216308

Disruption of cell walls for enhanced lipid recovery

Science.gov (United States)

Knoshaug, Eric P; Donohoe, Bryon S; Gerken, Henri; Laurens, Lieve; Van Wychen, Stefanie Rose

2015-03-24

Presented herein are methods of using cell wall degrading enzymes for recovery of internal lipid bodies from biomass sources such as algae. Also provided are algal cells that express at least one exogenous gene encoding a cell wall degrading enzyme and methods for recovering lipids from the cells.

Cell Wall Composition and Candidate Biosynthesis Gene Expression During Rice Development

Energy Technology Data Exchange (ETDEWEB)

Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra; Peck, Matthew L.; Vega-Sánchez, Miguel E.; Williams, Brian; Chiniquy, Dawn M.; Saha, Prasenjit; Pattathil, Sivakumar; Conlin, Brian; Zhu, Lan; Hahn, Michael G.; Willats, William G. T.; Scheller, Henrik V.; Ronald, Pamela C.; Bartley, Laura E.

2016-08-01

Cell walls of grasses, including cereal crops and biofuel grasses, comprise the majority of plant biomass and intimately influence plant growth, development and physiology. However, the functions of many cell wall synthesis genes, and the relationships among and the functions of cell wall components remain obscure. To better understand the patterns of cell wall accumulation and identify genes that act in grass cell wall biosynthesis, we characterized 30 samples from aerial organs of rice (Oryza sativa cv. Kitaake) at 10 developmental time points, 3-100 d post-germination. Within these samples, we measured 15 cell wall chemical components, enzymatic digestibility and 18 cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had previously been identified as being highly expressed in rice. Most cell wall components vary significantly during development, and correlations among them support current understanding of cell walls. We identified 92 significant correlations between cell wall components and gene expression and establish nine strong hypotheses for genes that synthesize xylans, mixed linkage glucan and pectin components. This work provides an extensive analysis of cell wall composition throughout rice development, identifies genes likely to synthesize grass cell walls, and provides a framework for development of genetically improved grasses for use in lignocellulosic biofuel production and agriculture.

Structural Studies of Complex Carbohydrates of Plant Cell Walls

Energy Technology Data Exchange (ETDEWEB)

Darvill, Alan [Univ. of Georgia, Athens, GA (United States); Hahn, Michael G. [Univ. of Georgia, Athens, GA (United States); O' Neill, Malcolm A. [Univ. of Georgia, Athens, GA (United States); York, William S. [Univ. of Georgia, Athens, GA (United States)

2015-02-17

Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell walls and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.

Wall relaxation and the driving forces for cell expansive growth

Science.gov (United States)

Cosgrove, D. J.

1987-01-01

When water uptake by growing cells is prevented, the turgor pressure and the tensile stress in the cell wall are reduced by continued wall loosening. This process, termed in vivo stress relaxation, provides a new way to study the dynamics of wall loosening and to measure the wall yield threshold and the physiological wall extensibility. Stress relaxation experiments indicate that wall stress supplies the mechanical driving force for wall yielding. Cell expansion also requires water absorption. The driving force for water uptake during growth is created by wall relaxation, which lowers the water potential of the expanding cells. New techniques for measuring this driving force show that it is smaller than believed previously; in elongating stems it is only 0.3 to 0.5 bar. This means that the hydraulic resistance of the water transport pathway is small and that rate of cell expansion is controlled primarily by wall loosening and yielding.

Oral candidosis by Candida albicans in normal and xerostomic mice Candidose oral por Candida albicans em camundongos normais e xerostômicos

Directory of Open Access Journals (Sweden)

Marilda Aparecida Gonçalves Totti

2004-09-01

Full Text Available The aim of this study was to analyze the effect of sialoadenectomy on the development of oral candidosis after one or four inoculations of Candida albicans. Initially, a suspension containing 10(8 cells/ml of C. albicans ATCC 36801 was prepared. Seventy-eight sialoadenectomized mice and a similar amount of mice with normal salivary flow received a single inoculation of C. albicans suspension. Another group with a similar number of mice received 4 inoculations. The control group consisted of 6 sialoadenectomized mice and 6 mice with normal salivary flow that were not inoculated with C. albicans. Candidosis development was studied histologically in the tongue of the animals 1, 2, 3, 5, and 8 days after inoculation and at 15-day intervals up to 165 days. According to the results obtained, it could be concluded that sialoadenectomy and a higher frequency of yeast inoculation influenced the presence and extension of candidosis lesions.O objetivo deste estudo foi analisar o efeito da sialoadenectomia sobre o desenvolvimento da candidose oral após uma ou quatro inoculações de Candida albicans. Inicialmente, uma suspensão contendo 10(8 células/ml de C. albicans ATCC 36801 foi preparada. Setenta e oito camundongos sialoadenectomizados e mesma quantidade de camundongos com fluxo salivar normal receberam uma única inoculação de suspensão de C. albicans. Outro grupo, com o mesmo número de camundongos, recebeu 4 inoculações. O grupo controle consistiu de 6 camundongos sialoadenectomizados e 6 com fluxo salivar normal que não foram inoculados com C. albicans. O desenvolvimento de candidose foi estudado histologicamente na língua dos animais em períodos de 1, 2, 3, 5 e 8 dias após a inoculação e em intervalos de 15 dias até 165 dias. De acordo com os resultados obtidos, conclui-se que a sialoadenectomia e uma maior freqüência de inoculação influenciaram na presença e extensão das lesões de candidose.

An enzymatic approach to cell wall structure | Hungate | South ...

African Journals Online (AJOL)

Ruminococcus albus was incubated with isolated alfalfa cell wall material for 72 h in batch culture. Cellulose in the cell walls was digested to a somewhat greater extent (88%) than were the fermentable sugars of the hemicellulose fraction (62- 76%). The digestibility of the total insoluble alfalfa cell wall, including lignin but ...

Minocycline Inhibits Candida albicans Budded-to-Hyphal-Form Transition and Biofilm Formation.

Science.gov (United States)

Kurakado, Sanae; Takatori, Kazuhiko; Sugita, Takashi

2017-09-25

Candida albicans frequently causes bloodstream infections; its budded-to-hyphalform transition (BHT) and biofilm formation are major contributors to virulence. During an analysis of antibacterial compounds that inhibit C. albicans BHT, we found that the tetracycline derivative minocycline inhibited BHT and subsequent biofilm formation. Minocycline decreased expression of hypha-specific genes HWP1 and ECE1, and adhesion factor gene ALS3 of C. albicans. In addition, minocycline decreased cell surface hydrophobicity and the extracellular β-glucan level in biofilms. Minocycline has been widely used for catheter antibiotic lock therapy to prevent bacterial infection; this compound may also be prophylactically effective against Candida infection.

Risk factors for fatal candidemia caused by Candida albicans and non-albicans Candida species

Directory of Open Access Journals (Sweden)

Tang Ran-Bin

2005-04-01

Full Text Available Abstract Background Invasive fungal infections, such as candidemia, caused by Candida species have been increasing. Candidemia is not only associated with a high mortality (30% to 40% but also extends the length of hospital stay and increases the costs of medical care. Sepsis caused by Candida species is clinically indistinguishable from bacterial infections. Although, the clinical presentations of the patients with candidemia caused by Candida albicans and non-albicans Candida species (NAC are indistinguishable, the susceptibilities to antifungal agents of these species are different. In this study, we attempted to identify the risk factors for candidemia caused by C. albicans and NAC in the hope that this may guide initial empiric therapy. Methods A retrospective chart review was conducted during 1996 to 1999 at the Veterans General Hospital-Taipei. Results There were 130 fatal cases of candidemia, including 68 patients with C. albicans and 62 with NAC. Candidemia was the most likely cause of death in 55 of the 130 patients (42.3 %. There was no significant difference in the distribution of Candida species between those died of candidemia and those died of underlying conditions. Patients who had one of the following conditions were more likely to have C. albicans, age ≧ 65 years, immunosuppression accounted to prior use of steroids, leukocytosis, in the intensive care unit (ICU, and intravascular and urinary catheters. Patients who had undergone cancer chemotherapy often appeared less critically ill and were more likely to have NAC. Conclusion Clinical and epidemiological differences in the risk factors between candidemia caused by C. albicans and NAC may provide helpful clues to initiate empiric therapy for patients infected with C. albicans versus NAC.

Risk factors for fatal candidemia caused by Candida albicans and non-albicans Candida species

Science.gov (United States)

Cheng, Ming-Fang; Yang, Yun-Liang; Yao, Tzy-Jyun; Lin, Chin-Yu; Liu, Jih-Shin; Tang, Ran-Bin; Yu, Kwok-Woon; Fan, Yu-Hua; Hsieh, Kai-Sheng; Ho, Monto; Lo, Hsiu-Jung

2005-01-01

Background Invasive fungal infections, such as candidemia, caused by Candida species have been increasing. Candidemia is not only associated with a high mortality (30% to 40%) but also extends the length of hospital stay and increases the costs of medical care. Sepsis caused by Candida species is clinically indistinguishable from bacterial infections. Although, the clinical presentations of the patients with candidemia caused by Candida albicans and non-albicans Candida species (NAC) are indistinguishable, the susceptibilities to antifungal agents of these species are different. In this study, we attempted to identify the risk factors for candidemia caused by C. albicans and NAC in the hope that this may guide initial empiric therapy. Methods A retrospective chart review was conducted during 1996 to 1999 at the Veterans General Hospital-Taipei. Results There were 130 fatal cases of candidemia, including 68 patients with C. albicans and 62 with NAC. Candidemia was the most likely cause of death in 55 of the 130 patients (42.3 %). There was no significant difference in the distribution of Candida species between those died of candidemia and those died of underlying conditions. Patients who had one of the following conditions were more likely to have C. albicans, age ≧ 65 years, immunosuppression accounted to prior use of steroids, leukocytosis, in the intensive care unit (ICU), and intravascular and urinary catheters. Patients who had undergone cancer chemotherapy often appeared less critically ill and were more likely to have NAC. Conclusion Clinical and epidemiological differences in the risk factors between candidemia caused by C. albicans and NAC may provide helpful clues to initiate empiric therapy for patients infected with C. albicans versus NAC. PMID:15813977

The effect of Candida albicans on the expression levels of toll-like receptor 2 and interleukin-8 in HaCaT cells under High- and Low-glucose conditions

Directory of Open Access Journals (Sweden)

Di Wang

2018-01-01

Full Text Available Background: The diabetics are prone to skin infections, especially with Candida albicans. It is important to elucidate the different antifungal abilities of patients with hyperglycemia and healthy controls for the treatment of this condition. The toll-like receptor 2 (TLR2 and interleukin (IL-8 secreted by keratinocytes counteract C. albicans. Aim: This study aims to explore the differential expression of toll-like receptor 2 (TLR2 and interleukin (IL-8 secretion by keratinocytes between controls and diabetic patients when challenged with C. albicans. Materials and Methods: HaCaT cells were cultured in high-glucose (HG Dulbecco's modified Eagle's medium (DMEM and low-glucose (LG DMEM. Then, they were exposed to C. albicans hyphae for 24 h. The expression levels of TLR2 and IL-8 were determined at different periods in both the HG and LG groups. Real-time polymerase chain reaction analysis, western blotting, and enzyme-linked immunosorbent assays were performed in this study. The morphological changes of HaCaT cells under two different glucose concentrations were also observed. Results: We found that the expression levels of both TLR2 and IL-8 increased and then decreased in the two groups. Notably, the IL-8 levels in the LG group were higher than those in the HG group at each time point (P<0.05, and the TLR2 levels in the LG group were higher than those in the HG group at the beginning of the experiment and after 24 h of treatment with C. albicans (P<0.05. In each group, the levels of IL-8 and TLR2 at the secretion peak were significantly different from those in the initial and the last period of observation (P<0.05. The cellular morphology of HaCaT cells treated with different concentrations of glucose was also similar. However, with prolonged coculture time, cell death increased. Conclusion: These observations showed that TLR2 and IL-8 act on the keratinocytes interacting with C. albicans, and HG status might affect the function of HaCaT cells

Pea Border Cell Maturation and Release Involve Complex Cell Wall Structural Dynamics.

Science.gov (United States)

Mravec, Jozef; Guo, Xiaoyuan; Hansen, Aleksander Riise; Schückel, Julia; Kračun, Stjepan Krešimir; Mikkelsen, Maria Dalgaard; Mouille, Grégory; Johansen, Ida Elisabeth; Ulvskov, Peter; Domozych, David S; Willats, William George Tycho

2017-06-01

The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases, though, plant cells are programmed to detach, and root cap-derived border cells are examples of this. Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment. Their maturation and release is an important but poorly characterized cell separation event. To gain a deeper insight into the complex cellular dynamics underlying this process, we undertook a systematic, detailed analysis of pea ( Pisum sativum ) root tip cell walls. Our study included immunocarbohydrate microarray profiling, monosaccharide composition determination, Fourier-transformed infrared microspectroscopy, quantitative reverse transcription-PCR of cell wall biosynthetic genes, analysis of hydrolytic activities, transmission electron microscopy, and immunolocalization of cell wall components. Using this integrated glycobiology approach, we identified multiple novel modes of cell wall structural and compositional rearrangement during root cap growth and the release of border cells. Our findings provide a new level of detail about border cell maturation and enable us to develop a model of the separation process. We propose that loss of adhesion by the dissolution of homogalacturonan in the middle lamellae is augmented by an active biophysical process of cell curvature driven by the polarized distribution of xyloglucan and extensin epitopes. © 2017 American Society of Plant Biologists. All Rights Reserved.

Magnetic domain wall conduits for single cell applications

DEFF Research Database (Denmark)

Donolato, Marco; Torti, A.; Kostesha, Natalie

2011-01-01

The ability to trap, manipulate and release single cells on a surface is important both for fundamental studies of cellular processes and for the development of novel lab-on-chip miniaturized tools for biological and medical applications. In this paper we demonstrate how magnetic domain walls...... walls over 16 hours. Moreover, we demonstrate the controlled transport and release of individual yeast cells via displacement and annihilation of individual domain walls in micro- and nano-sized magnetic structures. These results pave the way to the implementation of magnetic devices based on domain...... walls technology in lab-on-chip systems devoted to accurate individual cell trapping and manipulation....

The antagonistic effect of Saccharomyces boulardii on Candida albicans filamentation, adhesion and biofilm formation.

Science.gov (United States)

Krasowska, Anna; Murzyn, Anna; Dyjankiewicz, Agnieszka; Łukaszewicz, Marcin; Dziadkowiec, Dorota

2009-12-01

The dimorphic fungus Candida albicans is a member of the normal flora residing in the intestinal tract of humans. In spite of this, under certain conditions it can induce both superficial and serious systemic diseases, as well as be the cause of gastrointestinal infections. Saccharomyces boulardii is a yeast strain that has been shown to have applications in the prevention and treatment of intestinal infections caused by bacterial pathogens. The purpose of this study was to determine whether S. boulardii affects the virulence factors of C. albicans. We demonstrate the inhibitory effect of live S. boulardii cells on the filamentation (hyphae and pseudohyphae formation) of C. albicans SC5314 strain proportional to the amount of S. boulardii added. An extract from S. boulardii culture has a similar effect. Live S. boulardii and the extract from S. boulardii culture filtrate diminish C. albicans adhesion to and subsequent biofilm formation on polystyrene surfaces under both aerobic and microaerophilic conditions. This effect is very strong and requires lower doses of S. boulardii cells or concentrations of the extract than serum-induced filamentation tests. Saccharomyces boulardii has a strong negative effect on very important virulence factors of C. albicans, i.e. the ability to form filaments and to adhere and form biofilms on plastic surfaces.

Yeast cell wall chitin reduces wine haze formation.

Science.gov (United States)

Ndlovu, Thulile; Divol, Benoit; Bauer, Florian F

2018-04-27

Protein haze formation in bottled wines is a significant concern for the global wine industry and wine clarification before bottling is therefore a common but expensive practice. Previous studies have shown that wine yeast strains can reduce haze formation through the secretion of certain mannoproteins, but it has been suggested that other yeast-dependent haze protective mechanisms exist. On the other hand, addition of chitin has been shown to reduce haze formation, likely because grape chitinases have been shown to be the major contributors to haze. In this study, Chardonnay grape must fermented by various yeast strains resulted in wines with different protein haze levels indicating differences in haze protective capacities of the strains. The cell wall chitin levels of these strains were determined, and a strong correlation between cell wall chitin levels and haze protection capability was observed. To further evaluate the mechanism of haze protection, Escherichia coli -produced GFP-tagged grape chitinase was shown to bind efficiently to yeast cell walls in a cell wall chitin concentration-dependent manner, while commercial chitinase was removed from synthetic wine in quantities also correlated with the cell wall chitin levels of the strains. Our findings suggest a new mechanism of reducing wine haze, and propose a strategy for optimizing wine yeast strains to improve wine clarification. Importance In this study, we establish a new mechanism by which wine yeast strains can impact on the protein haze formation of wines, and demonstrate that yeast cell wall chitin binds grape chitinase in a chitin-concentration dependent manner. We also show that yeast can remove this haze-forming protein from wine. Chitin has in the past been shown to efficiently reduce wine haze formation when added to the wine in high concentration as a clarifying agent. Our data suggest that the selection of yeast strains with high levels of cell wall chitin can reduce protein haze. We also

Streptococcus agalactiae Inhibits Candida albicans Hyphal Development and Diminishes Host Vaginal Mucosal TH17 Response.

Science.gov (United States)

Yu, Xiao-Yu; Fu, Fei; Kong, Wen-Na; Xuan, Qian-Kun; Wen, Dong-Hua; Chen, Xiao-Qing; He, Yong-Ming; He, Li-Hua; Guo, Jian; Zhou, Ai-Ping; Xi, Yang-Hong; Ni, Li-Jun; Yao, Yu-Feng; Wu, Wen-Juan

2018-01-01

Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans , and that EFG1 -Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae , while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1 -Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans .

Novel Aggregation Properties of Candida albicans Secreted Aspartyl Proteinase Sap6 Mediate Virulence in Oral Candidiasis.

Science.gov (United States)

Kumar, Rohitashw; Saraswat, Darpan; Tati, Swetha; Edgerton, Mira

2015-07-01

Candida albicans, a commensal fungus of the oral microbiome, causes oral candidiasis in humans with localized or systemic immune deficiencies. Secreted aspartic proteinases (Saps) are a family of 10 related proteases and are virulence factors due to their proteolytic activity, as well as their roles in adherence and colonization of host tissues. We found that mice infected sublingually with C. albicans cells overexpressing Sap6 (SAP6 OE and a Δsap8 strain) had thicker fungal plaques and more severe oral infection, while infection with the Δsap6 strain was attenuated. These hypervirulent strains had highly aggregative colony structure in vitro and higher secreted proteinase activity; however, the levels of proteinase activity of C. albicans Saps did not uniformly match their abilities to damage cultured oral epithelial cells (SCC-15 cells). Hyphal induction in cells overexpressing Sap6 (SAP6 OE and Δsap8 cells) resulted in formation of large cell-cell aggregates. These aggregates could be produced in germinated wild-type cells by addition of native or heat-inactivated Sap6. Sap6 bound only to germinated cells and increased C. albicans adhesion to oral epithelial cells. The adhesion properties of Sap6 were lost upon deletion of its integrin-binding motif (RGD) and could be inhibited by addition of RGD peptide or anti-integrin antibodies. Thus, Sap6 (but not Sap5) has an alternative novel function in cell-cell aggregation, independent of its proteinase activity, to promote infection and virulence in oral candidiasis.

Polyethylene glycol-functionalized poly (Lactic Acid-co-Glycolic Acid and graphene oxide nanoparticles induce pro-inflammatory and apoptotic responses in Candida albicans-infected vaginal epithelial cells.

Directory of Open Access Journals (Sweden)

R Doug Wagner

Full Text Available Mucous-penetrating nanoparticles consisting of poly lactic acid-co-glycolic acid (PLGA-polyethylene glycol (PEG could improve targeting of microbicidal drugs for sexually transmitted diseases by intravaginal inoculation. Nanoparticles can induce inflammatory responses, which may exacerbate the inflammation that occurs in the vaginal tracts of women with yeast infections. This study evaluated the effects of these drug-delivery nanoparticles on VK2(E6/E7 vaginal epithelial cell proinflammatory responses to Candida albicans yeast infections. Vaginal epithelial cell monolayers were infected with C. albicans and exposed to 100 μg/ml 49.5 nm PLGA-PEG nanospheres or 20 μg/ml 1.1 x 500 nm PEG-functionalized graphene oxide (GO-PEG sheets. The cells were assessed for changes in mRNA and protein expression of inflammation-related genes by RT-qPCR and physiological markers of cell stress using high content analysis and flow cytometry. C. albicans exposure suppressed apoptotic gene expression, but induced oxidative stress in the cells. The nanomaterials induced cytotoxicity and programmed cell death responses alone and with C. albicans. PLGA-PEG nanoparticles induced mRNA expression of apoptosis-related genes and induced poly (ADP-ribose polymerase (PARP cleavage, increased BAX/BCL2 ratios, and chromatin condensation indicative of apoptosis. They also induced autophagy, endoplasmic reticulum stress, and DNA damage. They caused the cells to excrete inflammatory recruitment molecules chemokine (C-X-C motif ligand 1 (CXCL1, interleukin-1α (IL1A, interleukin-1β (IL1B, calprotectin (S100A8, and tumor necrosis factor α (TNF. GO-PEG nanoparticles induced expression of necrosis-related genes and cytotoxicity. They reduced autophagy and endoplasmic reticulum stress, and apoptotic gene expression responses. The results show that stealth nanoparticle drug-delivery vehicles may cause intracellular damage to vaginal epithelial cells by several mechanisms and that

Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells

DEFF Research Database (Denmark)

Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

2015-01-01

staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall......Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective...... with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain...

Pea border cell maturation and release involve complex cell wall structural dynamics

DEFF Research Database (Denmark)

Mravec, Jozef; Guo, Xiaoyuan; Hansen, Aleksander Riise

2017-01-01

The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases though, plant cells are programmed to detach and root cap-derived border cells are examples of this....... Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment. Their maturation and release is an important but poorly characterized cell separation event. To gain a deeper insight into the complex cellular dynamics underlying this process, we...... undertook a systematic, detailed analysis of pea (Pisum sativum) root tip cell walls. Our study included immuno-carbohydrate microarray profiling, monosaccharide composition determination, Fourier-transformed infrared microspectroscopy (FT-IR), quantitative RT-PCR of cell wall biosynthetic genes, analysis...

Cell wall composition and candidate biosynthesis gene expression during rice development

DEFF Research Database (Denmark)

Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra

2016-01-01

Cell walls of grasses, including cereal crops and biofuel grasses, comprise the majority of plant biomass and intimately influence plant growth, development and physiology. However, the functions of many cell wall synthesis genes, and the relationships among and the functions of cell wall...... components remain obscure. To better understand the patterns of cell wall accumulation and identify genes that act in grass cell wall biosynthesis, we characterized 30 samples from aerial organs of rice (Oryza sativa cv. Kitaake) at 10 developmental time points, 3-100 d post-germination. Within these samples......, we measured 15 cell wall chemical components, enzymatic digestibility and 18 cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had...

Immunocytochemical characterization of the cell walls of bean cell suspensions during habituation and dehabituation to dichlobenil

DEFF Research Database (Denmark)

Garcia-Angulo, P.; Willats, W. G. T.; Encina, A. E.

2006-01-01

The effects of the cellulose inhibitor dichlobenil on the cell wall composition and structure during the habituation/dehabituation process of suspension-cultured bean cells were assessed. A range of techniques were used including cell wall fractionation, sugar analysis, immunofluorescence...... and fluorochrome labelling of resin-embedded sections, and immunodot assays (IDAs) of cell wall fractions. The cell walls from bean cell suspensions with initial levels of habituation to dichlobenil had decreased levels of cellulose, but this effect lessened with increasing numbers of subcultures. All cell walls...

Reduced Wall Acetylation Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis

DEFF Research Database (Denmark)

Manabe, Yuzuki; Verhertbruggen, Yves; Gille, Sascha

2013-01-01

The Reduced Wall Acetylation (RWA) proteins are involved in cell wall acetylation in plants. Previously, we described a single mutant, rwa2, which has about 20% lower level of O-acetylation in leaf cell walls and no obvious growth or developmental phenotype. In this study, we generated double....... The quadruple rwa mutant can be completely complemented with the RWA2 protein expressed under 35S promoter, indicating the functional redundancy of the RWA proteins. Nevertheless, the degree of acetylation of xylan, (gluco) mannan, and xyloglucan as well as overall cell wall acetylation is affected differently...... in different combinations of triple mutants, suggesting their diversity in substrate preference. The overall degree of wall acetylation in the rwa quadruple mutant was reduced by 63% compared with the wild type, and histochemical analysis of the rwa quadruple mutant stem indicates defects in cell...

The Role of Pectin Acetylation in the Organization of Plant Cell Walls

DEFF Research Database (Denmark)

Fimognari, Lorenzo

adopt defined 3D organization to allow their composition/interactions to be tweaked upon developmental need. Failure to build functional cell wall architecture will affect plant growth and resistance to stresses. In this PhD dissertation I explored the role of pectin acetylation in controlling...... wall organization, namely polysaccharides-to-polysaccharides interactions. These results suggest that cell wall acetylation is a mechanism that plants evolved to control cell wall organization. In Manuscript III, we report the characterization of Arabidopsis mutants trichome birefringence like (tbl) 10......All plant cells are surrounded by one or more cell wall layers. The cell wall serves as a stiff mechanical support while it allows cells to expand and provide a protective barrier to invading pathogens. Cell walls are dynamic structures composed of entangled cell wall polysaccharides that must...

Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells.

Science.gov (United States)

Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

2015-01-01

Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

Cell wall staining with Trypan Blue enables quantitative analysis of morphological changes in yeast cells

Directory of Open Access Journals (Sweden)

Johannes eLiesche

2015-02-01

Full Text Available Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

Al-induced root cell wall chemical components differences of wheat ...

African Journals Online (AJOL)

Root growth is different in plants with different levels of Al-tolerance under Al stress. Cell wall chemical components of root tip cell are related to root growth. The aim of this study was to explore the relationship between root growth difference and cell wall chemical components. For this purpose, the cell wall chemical ...

Interactions of Condensed Tannins with Saccharomyces cerevisiae Yeast Cells and Cell Walls: Tannin Location by Microscopy.

Science.gov (United States)

Mekoue Nguela, Julie; Vernhet, Aude; Sieczkowski, Nathalie; Brillouet, Jean-Marc

2015-09-02

Interactions between grape tannins/red wine polyphenols and yeast cells/cell walls was previously studied within the framework of red wine aging and the use of yeast-derived products as an alternative to aging on lees. Results evidenced a quite different behavior between whole cells (biomass grown to elaborate yeast-derived products, inactivated yeast, and yeast inactivated after autolysis) and yeast cell walls (obtained from mechanical disruption of the biomass). Briefly, whole cells exhibited a high capacity to irreversibly adsorb grape and wine tannins, whereas only weak interactions were observed for cell walls. This last point was quite unexpected considering the literature and called into question the real role of cell walls in yeasts' ability to fix tannins. In the present work, tannin location after interactions between grape and wine tannins and yeast cells and cell walls was studied by means of transmission electron microscopy, light epifluorescence, and confocal microscopy. Microscopy observations evidenced that if tannins interact with cell walls, and especially cell wall mannoproteins, they also diffuse freely through the walls of dead cells to interact with their plasma membrane and cytoplasmic components.

Staphylococcus aureus adherence to Candida albicans hyphae is mediated by the hyphal adhesin Als3p.

Science.gov (United States)

Peters, Brian M; Ovchinnikova, Ekaterina S; Krom, Bastiaan P; Schlecht, Lisa Marie; Zhou, Han; Hoyer, Lois L; Busscher, Henk J; van der Mei, Henny C; Jabra-Rizk, Mary Ann; Shirtliff, Mark E

2012-12-01

The bacterium Staphylococcus (St.) aureus and the opportunistic fungus Candida albicans are currently among the leading nosocomial pathogens, often co-infecting critically ill patients, with high morbidity and mortality. Previous investigations have demonstrated preferential adherence of St. aureus to C. albicans hyphae during mixed biofilm growth. In this study, we aimed to characterize the mechanism behind this observed interaction. C. albicans adhesin-deficient mutant strains were screened by microscopy to identify the specific receptor on C. albicans hyphae recognized by St. aureus. Furthermore, an immunoassay was developed to validate and quantify staphylococcal binding to fungal biofilms. The findings from these experiments implicated the C. albicans adhesin agglutinin-like sequence 3 (Als3p) in playing a major role in the adherence process. This association was quantitatively established using atomic force microscopy, in which the adhesion force between single cells of the two species was significantly reduced for a C. albicans mutant strain lacking als3. Confocal microscopy further confirmed these observations, as St. aureus overlaid with a purified recombinant Als3 N-terminal domain fragment (rAls3p) exhibited robust binding. Importantly, a strain of Saccharomyces cerevisiae heterologously expressing Als3p was utilized to further confirm this adhesin as a receptor for St. aureus. Although the parental strain does not bind bacteria, expression of Als3p on the cell surface conferred upon the yeast the ability to strongly bind St. aureus. To elucidate the implications of these in vitro findings in a clinically relevant setting, an ex vivo murine model of co-infection was designed using murine tongue explants. Fluorescent microscopic images revealed extensive hyphal penetration of the epithelium typical of C. albicans mucosal infection. Interestingly, St. aureus bacterial cells were only seen within the epithelial tissue when associated with the invasive

2D-immunoblotting analysis of Sporothrix schenckii cell wall

Directory of Open Access Journals (Sweden)

Estela Ruiz-Baca

2011-03-01

Full Text Available We utilized two-dimensional gel electrophoresis and immunoblotting (2D-immunoblotting with anti-Sporothrix schenckii antibodies to identify antigenic proteins in cell wall preparations obtained from the mycelial and yeast-like morphologies of the fungus. Results showed that a 70-kDa glycoprotein (Gp70 was the major antigen detected in the cell wall of both morphologies and that a 60-kDa glycoprotein was present only in yeast-like cells. In addition to the Gp70, the wall from filament cells showed four proteins with molecular weights of 48, 55, 66 and 67 kDa, some of which exhibited several isoforms. To our knowledge, this is the first 2D-immunoblotting analysis of the S. schenckii cell wall.

Proteomic analysis of cell walls of two developmental stages of alfalfa stems

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Julian C Verdonk

2012-12-01

Full Text Available Cell walls are important for the growth and development of all plants. They are also valuable resources for feed and fiber, and more recently as a potential feedstock for bioenergy production. Cell wall proteins comprise only a fraction of the cell wall, but play important roles in establishing the walls and in the chemical interactions (e.g. crosslinking of cell wall components. This crosslinking provides structure, but restricts digestibility of cell wall complex carbohydrates, limiting available energy in animal and bioenergy production systems. Manipulation of cell wall proteins could be a strategy to improve digestibility. An analysis of the cell wall proteome of apical alfalfa stems (less mature, more digestible and basal alfalfa stems (more mature, less digestible was conducted using a recently developed low-salt/density gradient method for the isolation of cell walls. Walls were subsequently subjected to a modified extraction utilizing EGTA to remove pectins, followed by a LiCl extraction to isolate more tightly bound proteins. Recovered proteins were identified using shotgun proteomics. We identified 272 proteins in the alfalfa stem cell wall proteome, 153 of which had not previously been identified in cell wall proteomic analyses. Nearly 70% percent of the identified proteins were predicted to be secreted, as would be expected for most cell wall proteins, an improvement over previously published studies using traditional cell wall isolation methods. A comparison of our and several other cell wall proteomic studies indicates little overlap in identified proteins among them, which may be largely due to differences in the tissues used as well as differences in experimental approach.

Mechanical properties of plant cell walls probed by relaxation spectra

DEFF Research Database (Denmark)

Hansen, Steen Laugesen; Ray, Peter Martin; Karlsson, Anders Ola

2011-01-01

Relax, that deduces relaxation spectra from appropriate rheological measurements is presented and made accessible through a Web interface. BayesRelax models the cell wall as a continuum of relaxing elements, and the ability of the method to resolve small differences in cell wall mechanical properties is demonstrated......Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild...... type. This may be due to the plant’s ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply...

Enzymatic Modification of Plant Cell Wall Polysaccharides

DEFF Research Database (Denmark)

Øbro, Jens; Hayashi, Takahisa; Mikkelsen, Jørn Dalgaard

2011-01-01

Plant cell walls are intricate structures with remarkable properties, widely used in almost every aspect of our life. Cell walls consist largely of complex polysaccharides and there is often a need for chemical and biochemical processing before industrial use. There is an increasing demand...... for sustainable processes that replace chemical treatments with white biotechnology. Plants can contribute significantly to this sustainable process by producing plant or microbialenzymes in planta that are necessary for plant cell wall modification or total degradation. This will give rise to superior food...... fibres, hydrocolloids, paper,textile, animal feeds or biofuels. Classical microbial-based fermentation systems could in the future face serious competition from plant-based expression systems for enzyme production. Plant expressed enzymes can either be targeted to specific cellular compartments...

Suppression of humoral response during the course of Candida albicans infection in mice.

Science.gov (United States)

Valdez, J C; Meson, O E; de Valdez, G A; Sirena, A

1984-10-30

This paper aims at demonstrating the non-specific immunosuppression as regards thyme-dependent antigens sheep erythrocytes (SRBC) during the course of Candida albicans systemic infection. Three lots of syngeneic/BALB/c mice, 8-12 weeks of age, were used. The first normal lot was inoculated via the intraperitoneal route with a (SRBC) suspension (4 X 10(8) cells ml) in a Hank's balanced saline solution. The primary response of antibodies formed by splenic cells was measured from 4 to 8 days after inoculation using the direct plaque forming cells technique. The second lot was infected by the same route with a suspension of Candida albicans (1 X 10(7) cells). Positive retrocultures from the blood and kidneys of these infected mice were obtained. These yeasts cultivated in a Sabouraud medium were harvested after 20 h at 37 degrees C. Following the same methodology the immune response to SRBC was determined. The serum obtained from infected mice was transferred to a third lot of mice at different intervals during the course of the infection. The immune response to SRBC was done by the direct plaque-forming cells technique. Controls were carried out using normal donors and recipients. A suppression of the immune response was obtained as from the 2nd day of inoculation up to the 28th day. It was not possible to transfer such suppression passively by means of the serum. These results suggest that the systemic infection by Candida albicans induce a non-specific immunosuppression in the organism, already demonstrated in viral infections, bacteria, protozoaria and metazoaria in mammals. In some way, this will contribute to explain the mechanisms of immune response to Candida albicans.

Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption.

Science.gov (United States)

Luo, Ying; Wang, Jianguo; Liu, Bin; Wang, Zhouli; Yuan, Yahong; Yue, Tianli

2015-01-01

The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.

An emerging role of pectic rhamnogalacturonanII for cell wall integrity

OpenAIRE

Reboul, Rebecca; Tenhaken, Raimund

2012-01-01

The plant cell wall is a complex network of different polysaccharides and glycoproteins, showing high diversity in nature. The essential components, tethering cell wall are under debate, as novel mutants challenge established models. The mutant ugd2,3 with a reduced supply of the important wall precursor UDP-glucuronic acid reveals the critical role of the pectic compound rhamnogalacturonanII for cell wall stability. This polymer seems to be more important for cell wall integrity than the pre...

Catalysts of plant cell wall loosening [version 1; referees: 2 approved

OpenAIRE

Daniel J. Cosgrove

2016-01-01

The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyl...

The synthesis, regulation, and functions of sterols in Candida albicans: Well-known but still lots to learn.

Science.gov (United States)

Lv, Quan-Zhen; Yan, Lan; Jiang, Yuan-Ying

2016-08-17

Sterols are the basal components of the membranes of the fungal pathogen Candida albicans, and these membranes determine the susceptibility of C. albicans cells to a variety of stresses, such as ionic, osmotic and oxidative pressures, and treatment with antifungal drugs. The common antifungal azoles in clinical use are targeted to the biosynthesis of ergosterol. In the past years, the synthesis, storage and metabolism of ergosterol in Saccharomyces cerevisiae has been characterized in some detail; however, these processes has not been as well investigated in the human opportunistic pathogen C. albicans. In this review, we summarize the genes involved in ergosterol synthesis and regulation in C. albicans. As well, genes in S. cerevisiae implicated in ergosterol storage and conversions with other lipids are noted, as these provide us clues and directions for the study of the homologous genes in C. albicans. In this report we have particularly focused on the essential roles of ergosterol in the dynamic process of cell biology and its fundamental status in the biological membrane system that includes lipid rafts, lipid droplets, vacuoles and mitochondria. We believe that a thorough understanding of this classic and essential pathway will give us new ideas about drug resistance and morphological switching in C. albicans.

Engineering cell wall synthesis mechanism for enhanced PHB accumulation in E. coli.

Science.gov (United States)

Zhang, Xing-Chen; Guo, Yingying; Liu, Xu; Chen, Xin-Guang; Wu, Qiong; Chen, Guo-Qiang

2018-01-01

The rigidity of bacterial cell walls synthesized by a complicated pathway limit the cell shapes as coccus, bar or ellipse or even fibers. A less rigid bacterium could be beneficial for intracellular accumulation of poly-3-hydroxybutyrate (PHB) as granular inclusion bodies. To understand how cell rigidity affects PHB accumulation, E. coli cell wall synthesis pathway was reinforced and weakened, respectively. Cell rigidity was achieved by thickening the cell walls via insertion of a constitutive gltA (encoding citrate synthase) promoter in front of a series of cell wall synthesis genes on the chromosome of several E. coli derivatives, resulting in 1.32-1.60 folds increase of Young's modulus in mechanical strength for longer E. coli cells over-expressing fission ring FtsZ protein inhibiting gene sulA. Cell rigidity was weakened by down regulating expressions of ten genes in the cell wall synthesis pathway using CRISPRi, leading to elastic cells with more spaces for PHB accumulation. The regulation on cell wall synthesis changes the cell rigidity: E. coli with thickened cell walls accumulated only 25% PHB while cell wall weakened E. coli produced 93% PHB. Manipulation on cell wall synthesis mechanism adds another possibility to morphology engineering of microorganisms. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Evolution of the cell wall components during terrestrialization

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Alicja Banasiak

2014-12-01

Full Text Available Colonization of terrestrial ecosystems by the first land plants, and their subsequent expansion and diversification, were crucial for the life on the Earth. However, our understanding of these processes is still relatively poor. Recent intensification of studies on various plant organisms have identified the plant cell walls are those structures, which played a key role in adaptive processes during the evolution of land plants. Cell wall as a structure protecting protoplasts and showing a high structural plasticity was one of the primary subjects to changes, giving plants the new properties and capabilities, which undoubtedly contributed to the evolutionary success of land plants. In this paper, the current state of knowledge about some main components of the cell walls (cellulose, hemicelluloses, pectins and lignins and their evolutionary alterations, as preadaptive features for the land colonization and the plant taxa diversification, is summarized. Some aspects related to the biosynthesis and modification of the cell wall components, with particular emphasis on the mechanism of transglycosylation, are also discussed. In addition, new surprising discoveries related to the composition of various cell walls, which change how we perceive their evolution, are presented, such as the presence of lignin in red algae or MLG (1→3,(1→4-β-D-glucan in horsetails. Currently, several new and promising projects, regarding the cell wall, have started, deciphering its structure, composition and metabolism in the evolutionary context. That additional information will allow us to better understand the processes leading to the terrestrialization and the evolution of extant land plants.

Bioinspired metal-cell wall-metal sandwich structure on an individual bacterial cell scaffold.

Science.gov (United States)

Zhang, Xiaoliang; Yu, Mei; Liu, Jianhua; Li, Songmei

2012-08-25

Pd nanoparticles were introduced to individual Bacillus cells and dispersedly anchored on both the inside and outside of the cell walls. The anchored nanoparticles served as "seeds" to drive the formation of double metallic layers forming a metal-cell wall-metal sandwich structure at the single-cell level.

Phenotype-Based Screening of Small Molecules to Modify Plant Cell Walls Using BY-2 Cells.

Science.gov (United States)

Okubo-Kurihara, Emiko; Matsui, Minami

2018-01-01

The plant cell wall is an important and abundant biomass with great potential for use as a modern recyclable resource. For effective utilization of this cellulosic biomass, its ability to degrade efficiently is key point. With the aim of modifying the cell wall to allow easy decomposition, we used chemical biological technology to alter its structure. As a first step toward evaluating the chemicals in the cell wall we employed a phenotype-based approach using high-throughput screening. As the plant cell wall is essential in determining cell morphology, phenotype-based screening is particularly effective in identifying compounds that bring about alterations in the cell wall. For rapid and reproducible screening, tobacco BY-2 cell is an excellent system in which to observe cell morphology. In this chapter, we provide a detailed chemical biological methodology for studying cell morphology using tobacco BY-2 cells.

Tools to Understand Structural Property Relationships for Wood Cell Walls

Science.gov (United States)

Joseph E. Jakes; Daniel J. Yelle; Charles R. Frihart

2011-01-01

Understanding structure-property relationships for wood cell walls has been hindered by the complex polymeric structures comprising these cell walls and the difficulty in assessing meaningful mechanical property measurements of individual cell walls. To help overcome these hindrances, we have developed two experimental methods: 1) two-dimensional solution state nuclear...

The plant cell wall in the feeding sites of cyst nematodes.

Science.gov (United States)

Bohlmann, Holger; Sobczak, Miroslaw

2014-01-01

Plant parasitic cyst nematodes (genera Heterodera and Globodera) are serious pests for many crops. They enter the host roots as migratory second stage juveniles (J2) and migrate intracellularly toward the vascular cylinder using their stylet and a set of cell wall degrading enzymes produced in the pharyngeal glands. They select an initial syncytial cell (ISC) within the vascular cylinder or inner cortex layers to induce the formation of a multicellular feeding site called a syncytium, which is the only source of nutrients for the parasite during its entire life. A syncytium can consist of more than hundred cells whose protoplasts are fused together through local cell wall dissolutions. While the nematode produces a cocktail of cell wall degrading and modifying enzymes during migration through the root, the cell wall degradations occurring during syncytium development are due to the plants own cell wall modifying and degrading proteins. The outer syncytial cell wall thickens to withstand the increasing osmotic pressure inside the syncytium. Furthermore, pronounced cell wall ingrowths can be formed on the outer syncytial wall at the interface with xylem vessels. They increase the surface of the symplast-apoplast interface, thus enhancing nutrient uptake into the syncytium. Processes of cell wall degradation, synthesis and modification in the syncytium are facilitated by a variety of plant proteins and enzymes including expansins, glucanases, pectate lyases and cellulose synthases, which are produced inside the syncytium or in cells surrounding the syncytium.

The plant cell wall in the feeding sites of cyst nematodes

Directory of Open Access Journals (Sweden)

Holger eBohlmann

2014-03-01

Full Text Available Plant parasitic cyst nematodes (genera Heterodera and Globodera are serious pests for many crops. They enter the host roots as migratory second stage juveniles (J2 and migrate intracellularly towards the vascular cylinder using their stylet and a set of cell wall degrading enzymes produced in the pharyngeal glands. They select an initial syncytial cell (ISC within the vascular cylinder or inner cortex layers to induce the formation of a multicellular feeding site called a syncytium, which is the only source of nutrients for the parasite during its entire life. A syncytium can consist of more than hundred cells whose protoplasts are fused together through local cell wall dissolutions. While the nematode produces a cocktail of cell wall degrading and modifying enzymes during migration through the root, the cell wall degradations occurring during syncytium development are due to the plants own cell wall modifying and degrading proteins. The outer syncytial cell wall thickens to withstand the increasing osmotic pressure inside the syncytium. Furthermore, pronounced cell wall ingrowths can be formed on the outer syncytial wall at the interface with xylem vessels. They increase the surface of the symplast-apoplast interface, thus enhancing nutrient uptake into the syncytium. Processes of cell wall degradation, synthesis and modification in the syncytium are facilitated by a variety of plant proteins and enzymes including expansins, glucanases, pectate lyases and cellulose synthases, which are produced inside the syncytium or in cells surrounding the syncytium.

Symbiotic Plant Peptides Eliminate Candida albicans Both In Vitro and in an Epithelial Infection Model and Inhibit the Proliferation of Immortalized Human Cells

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Lilla Ördögh

2014-01-01

Full Text Available The increasing number of multidrug-resistant microbes now emerging necessitates the identification of novel antimicrobial agents. Plants produce a great variety of antimicrobial peptides including hundreds of small, nodule-specific cysteine-rich NCR peptides that, in the legume Medicago truncatula, govern the differentiation of endosymbiotic nitrogen fixing bacteria and, in vitro, can display potent antibacterial activities. In this study, the potential candidacidal activity of 19 NCR peptides was investigated. Cationic NCR peptides having an isoelectric point above 9 were efficient in killing Candida albicans, one of the most common fungal pathogens of humans. None of the tested NCR peptides were toxic for immortalized human epithelial cells at concentrations that effectively killed the fungus; however, at higher concentrations, some of them inhibited the division of the cells. Furthermore, the cationic peptides successfully inhibited C. albicans induced human epithelial cell death in an in vitro coculture model. These results highlight the therapeutic potential of cationic NCR peptides in the treatment of candidiasis.

Streptococcus agalactiae Inhibits Candida albicans Hyphal Development and Diminishes Host Vaginal Mucosal TH17 Response

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Xiao-Yu Yu

2018-02-01

Full Text Available Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC, the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae, while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1-Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans.

Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

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Jean-Claude Mollet

2013-03-01

Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

Dynamic changes in transcriptome and cell wall composition underlying brassinosteroid-mediated lignification of switchgrass suspension cells.

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Rao, Xiaolan; Shen, Hui; Pattathil, Sivakumar; Hahn, Michael G; Gelineo-Albersheim, Ivana; Mohnen, Debra; Pu, Yunqiao; Ragauskas, Arthur J; Chen, Xin; Chen, Fang; Dixon, Richard A

2017-01-01

Plant cell walls contribute the majority of plant biomass that can be used to produce transportation fuels. However, the complexity and variability in composition and structure of cell walls, particularly the presence of lignin, negatively impacts their deconstruction for bioenergy. Metabolic and genetic changes associated with secondary wall development in the biofuel crop switchgrass ( Panicum virgatum ) have yet to be reported. Our previous studies have established a cell suspension system for switchgrass, in which cell wall lignification can be induced by application of brassinolide (BL). We have now collected cell wall composition and microarray-based transcriptome profiles for BL-induced and non-induced suspension cultures to provide an overview of the dynamic changes in transcriptional reprogramming during BL-induced cell wall modification. From this analysis, we have identified changes in candidate genes involved in cell wall precursor synthesis, cellulose, hemicellulose, and pectin formation and ester-linkage generation. We have also identified a large number of transcription factors with expression correlated with lignin biosynthesis genes, among which are candidates for control of syringyl (S) lignin accumulation. Together, this work provides an overview of the dynamic compositional changes during brassinosteroid-induced cell wall remodeling, and identifies candidate genes for future plant genetic engineering to overcome cell wall recalcitrance.

The receptor-like kinase AtVRLK1 regulates secondary cell wall thickening.

Science.gov (United States)

Huang, Cheng; Zhang, Rui; Gui, Jinshan; Zhong, Yu; Li, Laigeng

2018-04-20

During the growth and development of land plants, some specialized cells, such as tracheary elements, undergo secondary cell wall thickening. Secondary cell walls contain additional lignin, compared with primary cell walls, thus providing mechanical strength and potentially improving defenses against pathogens. However, the molecular mechanisms that initiate wall thickening are unknown. In this study, we identified an Arabidopsis thaliana leucine-rich repeat receptor-like kinase, encoded by AtVRLK1 (Vascular-Related RLK 1), that is specifically expressed in cells undergoing secondary cell wall thickening. Suppression of AtVRLK1expression resulted in a range of phenotypes that included retarded early elongation of the inflorescence stem, shorter fibers, slower root growth, and shorter flower filaments. In contrast, upregulation of AtVRLK1 led to longer fiber cells, reduced secondary cell wall thickening in fiber and vessel cells, and defects in anther dehiscence. Molecular and cellular analyses showed that downregulation of AtVRLK1 promoted secondary cell wall thickening and upregulation of AtVRLK1 enhanced cell elongation and inhibited secondary cell wall thickening. We propose that AtVRLK1 functions as a signaling component in coordinating cell elongation and cell wall thickening during growth and development. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

Evidence for differentiation of cell wall poles in Bacillus subtilis

International Nuclear Information System (INIS)

Sonnenfeld, E.M.

1985-01-01

Previous data have suggested that the chromosome of Bacillus subtilis was found to the cell surface at polar regions. A significant corollary of DNA attachment to cell poles is the role of the cell wall in chromosome segregation. This project was mainly concerned with visualizing the DNA-cell wall association through autoradiography. The origin and terminus of replication were labelled with ( 3 H)-thymidine using a temperature-sensitive DNA initiation mutant. It was found that most of the radioactivity was associated with cell poles. Ultrastructural analyses of cell walls stained with dilute cationized ferritin showed that the polar area contained a site of dense electronegativity. It is not immediately apparent why cell wall poles would contain an area with a high concentration of negative charge. This finding may be related to the cell pole functioning as the site of chromosome attachment. An additional observation encountered in this study was that cell wall exhibited asymmetry with regard to negative charge, the outside surface being more electronegative than the inside. A significant consequence of this finding is that both teichoic acid and muramyl peptides are situated perpendicularly to the cell surface. This favored arrangement may facilitate cell separation during the division process due to opposition of like charges at septa. The results of this work provide further convincing evidence that the cell wall of B. subtilis is differentiated

Hemicellulose biosynthesis and degradation in tobacco cell walls

NARCIS (Netherlands)

Compier, M.G.M.

2005-01-01

Natural fibres have a wide range of technological applications, such as in paper and textile industries. The basic properties and the quality of plant fibres are determined by the composition of the plant cell wall. Characteristic for fibres are thick secondary cell walls, which consist of cellulose

Binding of 18F by cell membranes and cell walls of Streptococcus mutans

International Nuclear Information System (INIS)

Yotis, W.W.; Zeb, M.; McNulty, J.; Kirchner, F.; Reilly, C.; Glendenin, L.

1983-01-01

The binding of 18 F to isolated cell membranes and cell walls of Streptococcus mutans GS-5 or other bacteria was assayed. The attachment of 18 F to these cell envelopes proceeded slowly and reached equilibrium within 60 min. 18 F binding was stimulated by Ca 2+ (1 mM). The binding of 18 F to cellular components was dependent upon the pH, as well as the amount of 18 F and dose of the binder employed. The binding of 18 F by cell walls prepared from fluoride-sensitive and fluoride-resistant cells of S. salivarius and S. mutans did not differ significantly. The pretreatment of cell walls or cell membranes for 60 min at 30 degrees C with 1 mg of RNase, DNase, or trypsin per ml did not influence the binding of 18 F by the walls and membranes of S. mutans GS-5. However, prior exposure of cell membranes to sodium dodecyl sulfate caused a significant reduction in the number of 18 F atoms bound by the membranes. In saturated assay systems, cell membranes of S. mutans GS-5 bound 10(15) to 10(16) atoms of 18 F per mg (dry weight), whereas cell walls from S. mutans GS-5, FA-1, and HS-6 or Actinomyces viscosus T14V and T14AV bound 10(12) to 10(13) atoms of 18 F per mg (dry weight). 18 F in this quantity (10(12) to 10(13) atoms) cannot be detected with the fluoride electrode. The data provide, for the first time, a demonstration of 18 F binding by cell membranes and walls of oral flora

Enzymes and other agents that enhance cell wall extensibility

Science.gov (United States)

Cosgrove, D. J.

1999-01-01

Polysaccharides and proteins are secreted to the inner surface of the growing cell wall, where they assemble into a network that is mechanically strong, yet remains extensible until the cells cease growth. This review focuses on the agents that directly or indirectly enhance the extensibility properties of growing walls. The properties of expansins, endoglucanases, and xyloglucan transglycosylases are reviewed and their postulated roles in modulating wall extensibility are evaluated. A summary model for wall extension is presented, in which expansin is a primary agent of wall extension, whereas endoglucanases, xyloglucan endotransglycosylase, and other enzymes that alter wall structure act secondarily to modulate expansin action.

Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption.

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Ying Luo

Full Text Available The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.

Structural analysis of cell wall polysaccharides using PACE

Energy Technology Data Exchange (ETDEWEB)

Mortimer, Jennifer C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Institute

2017-01-01

The plant cell wall is composed of many complex polysaccharides. The composition and structure of the polysaccharides affect various cell properties including cell shape, cell function and cell adhesion. Many techniques to characterize polysaccharide structure are complicated, requiring expensive equipment and specialized operators e.g. NMR, MALDI-MS. PACE (Polysaccharide Analysis using Carbohydrate gel Electrophoresis) uses a simple, rapid technique to analyze polysaccharide quantity and structure (Goubet et al. 2002). Whilst the method here describes xylan analysis, it can be applied (by use of the appropriate glycosyl hydrolase) to any cell wall polysaccharide.

Candida albicans versus Candida dubliniensis: Why Is C. albicans More Pathogenic?

LENUS (Irish Health Repository)

Moran, Gary P

2012-01-01

Candida albicans and Candida dubliniensis are highly related pathogenic yeast species. However, C. albicans is far more prevalent in human infection and has been shown to be more pathogenic in a wide range of infection models. Comparison of the genomes of the two species has revealed that they are very similar although there are some significant differences, largely due to the expansion of virulence-related gene families (e.g., ALS and SAP) in C. albicans, and increased levels of pseudogenisation in C. dubliniensis. Comparative global gene expression analyses have also been used to investigate differences in the ability of the two species to tolerate environmental stress and to produce hyphae, two traits that are likely to play a role in the lower virulence of C. dubliniensis. Taken together, these data suggest that C. dubliniensis is in the process of undergoing reductive evolution and may have become adapted for growth in a specialized anatomic niche.

Isolation of a novel cell wall architecture mutant of rice with defective Arabidopsis COBL4 ortholog BC1 required for regulated deposition of secondary cell wall components.

Science.gov (United States)

Sato, Kanna; Suzuki, Ryu; Nishikubo, Nobuyuki; Takenouchi, Sachi; Ito, Sachiko; Nakano, Yoshimi; Nakaba, Satoshi; Sano, Yuzou; Funada, Ryo; Kajita, Shinya; Kitano, Hidemi; Katayama, Yoshihiro

2010-06-01

The plant secondary cell wall is a highly ordered structure composed of various polysaccharides, phenolic components and proteins. Its coordinated regulation of a number of complex metabolic pathways and assembly has not been resolved. To understand the molecular mechanisms that regulate secondary cell wall synthesis, we isolated a novel rice mutant, cell wall architecture1 (cwa1), that exhibits an irregular thickening pattern in the secondary cell wall of sclerenchyma, as well as culm brittleness and reduced cellulose content in mature internodes. Light and transmission electron microscopy revealed that the cwa1 mutant plant has regions of local aggregation in the secondary cell walls of the cortical fibers in its internodes, showing uneven thickness. Ultraviolet microscopic observation indicated that localization of cell wall phenolic components was perturbed and that these components abundantly deposited at the aggregated cell wall regions in sclerenchyma. Therefore, regulation of deposition and assembly of secondary cell wall materials, i.e. phenolic components, appear to be disturbed by mutation of the cwa1 gene. Genetic analysis showed that cwa1 is allelic to brittle culm1 (bc1), which encodes the glycosylphosphatidylinositol-anchored COBRA-like protein specifically in plants. BC1 is known as a regulator that controls the culm mechanical strength and cellulose content in the secondary cell walls of sclerenchyma, but the precise function of BC1 has not been resolved. Our results suggest that CWA1/BC1 has an essential role in assembling cell wall constituents at their appropriate sites, thereby enabling synthesis of solid and flexible internodes in rice.

Oral Immunization Against Candidiasis Using Lactobacillus casei Displaying Enolase 1 from Candida albicans.

Science.gov (United States)

Shibasaki, Seiji; Karasaki, Miki; Tafuku, Senji; Aoki, Wataru; Sewaki, Tomomitsu; Ueda, Mitsuyoshi

2014-01-01

Candidiasis is a common fungal infection that is prevalent in immunocompromised individuals. In this study, an oral vaccine against Candida albicans was developed by using the molecular display approach. Enolase 1 protein (Eno1p) of C. albicans was expressed on the Lactobacillus casei cell surface by using poly-gamma-glutamic acid synthetase complex A from Bacillus subtilis as an anchoring protein. The Eno1p-displaying L. casei cells were used to immunize mice, which were later challenged with a lethal dose of C. albicans. The data indicated that the vaccine elicited a strong IgG response and increased the survival rate of the vaccinated mice. Furthermore, L. casei acted as a potent adjuvant and induced high antibody titers that were comparable to those induced by strong adjuvants such as the cholera toxin. Overall, the molecular display method can be used to rapidly develop vaccines that can be conveniently administered and require minimal processing.

Endotoxins, Glucans and Other Microbial Cell Wall Agents

NARCIS (Netherlands)

Basinas, Ioannis; Elholm, Grethe; Wouters, Inge M.

2017-01-01

During the last decades an increasing interest in microbial cell wall agents has been established, since exposure to these agents has been linked to a wide range of adverse and beneficial health effects. The term microbial cell wall agents refers to a group of molecules of different composition that

Characterising the cellulose synthase complexes of cell walls

NARCIS (Netherlands)

Mansoori Zangir, N.

2012-01-01

One of the characteristics of the plant kingdom is the presence of a structural cell wall. Cellulose is a major component in both the primary and secondary cell walls of plants. In higher plants cellulose is synthesized by so called rosette protein complexes with cellulose synthases (CESAs) as

Magnetic field exposure stiffens regenerating plant protoplast cell walls.

Science.gov (United States)

Haneda, Toshihiko; Fujimura, Yuu; Iino, Masaaki

2006-02-01

Single suspension-cultured plant cells (Catharanthus roseus) and their protoplasts were anchored to a glass plate and exposed to a magnetic field of 302 +/- 8 mT for several hours. Compression forces required to produce constant cell deformation were measured parallel to the magnetic field by means of a cantilever-type force sensor. Exposure of intact cells to the magnetic field did not result in any changes within experimental error, while exposure of regenerating protoplasts significantly increased the measured forces and stiffened regenerating protoplasts. The diameters of intact cells or regenerating protoplasts were not changed after exposure to the magnetic field. Measured forces for regenerating protoplasts with and without exposure to the magnetic field increased linearly with incubation time, with these forces being divided into components based on the elasticity of synthesized cell walls and cytoplasm. Cell wall synthesis was also measured using a cell wall-specific fluorescent dye, and no changes were noted after exposure to the magnetic field. Analysis suggested that exposure to the magnetic field roughly tripled the Young's modulus of the newly synthesized cell wall without any lag.

Bacterial glycobiology: rhamnose-containing cell wall polysaccharides in Gram-positive bacteria.

Science.gov (United States)

Mistou, Michel-Yves; Sutcliffe, Iain C; van Sorge, Nina M

2016-07-01

The composition of the Gram-positive cell wall is typically described as containing peptidoglycan, proteins and essential secondary cell wall structures called teichoic acids, which comprise approximately half of the cell wall mass. The cell walls of many species within the genera Streptococcus, Enterococcus and Lactococcus contain large amounts of the sugar rhamnose, which is incorporated in cell wall-anchored polysaccharides (CWP) that possibly function as homologues of well-studied wall teichoic acids (WTA). The presence and chemical structure of many rhamnose-containing cell wall polysaccharides (RhaCWP) has sometimes been known for decades. In contrast to WTA, insight into the biosynthesis and functional role of RhaCWP has been lacking. Recent studies in human streptococcal and enterococcal pathogens have highlighted critical roles for these complex polysaccharides in bacterial cell wall architecture and pathogenesis. In this review, we provide an overview of the RhaCWP with regards to their biosynthesis, genetics and biological function in species most relevant to human health. We also briefly discuss how increased knowledge in this field can provide interesting leads for new therapeutic compounds and improve biotechnological applications. © FEMS 2016.

Candida albicans adherence to resin-composite restorative dental material: influence of whole human saliva.

Science.gov (United States)

Maza, José Luis; Elguezabal, Natalia; Prado, Carlota; Ellacuría, Joseba; Soler, Iñaki; Pontón, José

2002-11-01

Attachment of Candida albicans to oral surfaces is believed to be a critical event in the colonization of the oral cavity and in the development of oral diseases such as Candida-associated denture stomatitis. Although there is considerable information about the adhesion of C albicans to buccal epithelial cells and prosthetic materials, there is very little information about the adhesion of C albicans to composite restorative materials. The purpose of this study was to investigate the degree of adhesion of C albicans to a resin-composite restorative material (Herculite). The adhesion of 2 strains of C albicans, a germinative and a germ tube-deficient mutant, was studied by a visual method after incubating the fungus and the resin with and without human whole saliva. In absence of saliva, the adhesion of the C albicans germinative isolate to the resin showed an increase in parallel with the germination, reaching a maximum at the end of the experiment (120 minutes). However, no significant differences were observed in the adhesion of the agerminative mutant during the period of time studied. In the presence of saliva, the adhesion of both isolates to the resin was significantly lowered. Germination and the presence of human whole saliva are important factors in the adhesion of C albicans to the resin-composite restorative material Herculite.

Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis

Science.gov (United States)

Goldenbogen, Björn; Giese, Wolfgang; Hemmen, Marie; Uhlendorf, Jannis; Herrmann, Andreas

2016-01-01

The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells. PMID:27605377

Characterizing visible and invisible cell wall mutant phenotypes

Energy Technology Data Exchange (ETDEWEB)

Carpita, Nicholas C.; McCann, Maureen C.

2015-04-06

About 10% of a plant's genome is devoted to generating the protein machinery to synthesize, remodel, and deconstruct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with ‘invisible’ phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basis of deviation from the wild type in genetic functional analyses to insights provided by modern analytical techniques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide components of the plant cell wall.

Genome-wide analysis of cell wall-related genes in Tuber melanosporum.

Science.gov (United States)

Balestrini, Raffaella; Sillo, Fabiano; Kohler, Annegret; Schneider, Georg; Faccio, Antonella; Tisserant, Emilie; Martin, Francis; Bonfante, Paola

2012-06-01

A genome-wide inventory of proteins involved in cell wall synthesis and remodeling has been obtained by taking advantage of the recently released genome sequence of the ectomycorrhizal Tuber melanosporum black truffle. Genes that encode cell wall biosynthetic enzymes, enzymes involved in cell wall polysaccharide synthesis or modification, GPI-anchored proteins and other cell wall proteins were identified in the black truffle genome. As a second step, array data were validated and the symbiotic stage was chosen as the main focus. Quantitative RT-PCR experiments were performed on 29 selected genes to verify their expression during ectomycorrhizal formation. The results confirmed the array data, and this suggests that cell wall-related genes are required for morphogenetic transition from mycelium growth to the ectomycorrhizal branched hyphae. Labeling experiments were also performed on T. melanosporum mycelium and ectomycorrhizae to localize cell wall components.

Studies on effect of Microbial Iron Chelators on Candida Albican

International Nuclear Information System (INIS)

Rehmani, Fouzia S.; Milicent, S.; Zaheer-Uddin

2005-01-01

Iron is an essential for the life of all microbe cells. It generally exists in the oxidized form Fe(III). Even under anaerobic reducing condition the metal appear to be taken up as Fe(III). Thus free-living microorganisms require specific and effective ferric ion transport system to cope with low availability of the metal. In iron deficient environment they produce a low molecular weight specific chelators called siderphores or microbial iron chelators. Siderphores compete for limited supplied of iron. These compounds came out of the cell but can not re-enter without iron due to high affinity of these siderphores often have more than one catechol/hydroxamate functions and are multidentate (usually hexadentate ligands). The aim of the present research is to check the effect of iron chelators, namely gallic acid and salisyl hydroxamate on the growth of Candida albican in vitro. C. albican is the opportunistic paltogen present as the normal flora inside human body. In vivo the growth of C. albican is distributed by the use of antibiotics and immuno suppressers. In cases of iron over-dosage in human being, the patients are treated with certain a-iron chelators. Hence an attempt is made to notice the effect that might be inhibition or enhancement of the organism in vitro. (author)

Pea Border Cell Maturation and Release Involve Complex Cell Wall Structural Dynamics1[OPEN

Science.gov (United States)

2017-01-01

The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases, though, plant cells are programmed to detach, and root cap-derived border cells are examples of this. Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment. Their maturation and release is an important but poorly characterized cell separation event. To gain a deeper insight into the complex cellular dynamics underlying this process, we undertook a systematic, detailed analysis of pea (Pisum sativum) root tip cell walls. Our study included immunocarbohydrate microarray profiling, monosaccharide composition determination, Fourier-transformed infrared microspectroscopy, quantitative reverse transcription-PCR of cell wall biosynthetic genes, analysis of hydrolytic activities, transmission electron microscopy, and immunolocalization of cell wall components. Using this integrated glycobiology approach, we identified multiple novel modes of cell wall structural and compositional rearrangement during root cap growth and the release of border cells. Our findings provide a new level of detail about border cell maturation and enable us to develop a model of the separation process. We propose that loss of adhesion by the dissolution of homogalacturonan in the middle lamellae is augmented by an active biophysical process of cell curvature driven by the polarized distribution of xyloglucan and extensin epitopes. PMID:28400496

Moonlight-like proteins of the cell wall protect sessile cells of Candida from oxidative stress.

Science.gov (United States)

Serrano-Fujarte, Isela; López-Romero, Everardo; Cuéllar-Cruz, Mayra

2016-01-01

Biofilms of Candida species are associated with high morbidity and hospital mortality. Candida forms biofilms by adhering to human host epithelium through cell wall proteins (CWP) and simultaneously neutralizing the reactive oxygen species (ROS) produced during the respiratory burst by phagocytic cells. The purpose of this paper is to identify the CWP of Candida albicans, Candida glabrata, Candida krusei and Candida parapsilosis expressed after exposure to different concentrations of H2O2 using a proteomic approach. CWP obtained from sessile cells, both treated and untreated with the oxidizing agent, were resolved by one and two-dimensional (2D-PAGE) gels and identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Some of these proteins were identified and found to correspond to moonlighting CWP such as: (i) glycolytic enzymes, (ii) heat shock, (iii) OSR proteins, (iv) general metabolic enzymes and (v) highly conserved proteins, which are up- or down-regulated in the presence or absence of ROS. We also found that the expression of these CWP is different for each Candida species. Moreover, RT-PCR assays allowed us to demonstrate that transcription of the gene coding for Eno1, one of the moonlight-like CWP identified in response to the oxidant agent, is differentially regulated. To our knowledge this is the first demonstration that, in response to oxidative stress, each species of Candida, differentially regulates the expression of moonlighting CWP, which may protect the organism from the ROS generated during phagocytosis. Presumptively, these proteins allow the pathogen to adhere and form a biofilm, and eventually cause invasive candidiasis in the human host. We propose that, in addition to the antioxidant mechanisms present in Candida, the moonlighting CWP also confer protection to these pathogens from oxidative stress. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discovery of novel cell wall-active compounds using P ywaC, a sensitive reporter of cell wall stress, in the model gram-positive bacterium Bacillus subtilis.

Science.gov (United States)

Czarny, T L; Perri, A L; French, S; Brown, E D

2014-06-01

The emergence of antibiotic resistance in recent years has radically reduced the clinical efficacy of many antibacterial treatments and now poses a significant threat to public health. One of the earliest studied well-validated targets for antimicrobial discovery is the bacterial cell wall. The essential nature of this pathway, its conservation among bacterial pathogens, and its absence in human biology have made cell wall synthesis an attractive pathway for new antibiotic drug discovery. Herein, we describe a highly sensitive screening methodology for identifying chemical agents that perturb cell wall synthesis, using the model of the Gram-positive bacterium Bacillus subtilis. We report on a cell-based pilot screen of 26,000 small molecules to look for cell wall-active chemicals in real time using an autonomous luminescence gene cluster driven by the promoter of ywaC, which encodes a guanosine tetra(penta)phosphate synthetase that is expressed under cell wall stress. The promoter-reporter system was generally much more sensitive than growth inhibition testing and responded almost exclusively to cell wall-active antibiotics. Follow-up testing of the compounds from the pilot screen with secondary assays to verify the mechanism of action led to the discovery of 9 novel cell wall-active compounds. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Mechanical feedback coordinates cell wall expansion and assembly in yeast mating morphogenesis

Science.gov (United States)

2018-01-01

The shaping of individual cells requires a tight coordination of cell mechanics and growth. However, it is unclear how information about the mechanical state of the wall is relayed to the molecular processes building it, thereby enabling the coordination of cell wall expansion and assembly during morphogenesis. Combining theoretical and experimental approaches, we show that a mechanical feedback coordinating cell wall assembly and expansion is essential to sustain mating projection growth in budding yeast (Saccharomyces cerevisiae). Our theoretical results indicate that the mechanical feedback provided by the Cell Wall Integrity pathway, with cell wall stress sensors Wsc1 and Mid2 increasingly activating membrane-localized cell wall synthases Fks1/2 upon faster cell wall expansion, stabilizes mating projection growth without affecting cell shape. Experimental perturbation of the osmotic pressure and cell wall mechanics, as well as compromising the mechanical feedback through genetic deletion of the stress sensors, leads to cellular phenotypes that support the theoretical predictions. Our results indicate that while the existence of mechanical feedback is essential to stabilize mating projection growth, the shape and size of the cell are insensitive to the feedback. PMID:29346368

Capric acid secreted by S. boulardii inhibits C. albicans filamentous growth, adhesion and biofilm formation.

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Anna Murzyn

Full Text Available Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and

Capric Acid Secreted by S. boulardii Inhibits C. albicans Filamentous Growth, Adhesion and Biofilm Formation

Science.gov (United States)

Murzyn, Anna; Krasowska, Anna; Stefanowicz, Piotr; Dziadkowiec, Dorota; Łukaszewicz, Marcin

2010-01-01

Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation. PMID

Adhesion of Candida albicans to Vanillin Incorporated Self-Curing Orthodontic PMMA Resin.

Science.gov (United States)

Zam, K.; Sawaengkit, P.; Thaweboon, S.; Thaweboon, B.

2018-02-01

It has been observed that there is an increase in Candida carriers during the treatment with orthodontic removable appliance. Vanillin is flavouring agent, which is known to have antioxidant and antimicrobial properties. The aim of this study was to evaluate the effect of vanillin incorporated PMMA on adhesion of Candida albicans. A total of 36 orthodontic self-curing PMMA resin samples were fabricated. The samples were divided into 3 groups depending on percentage of vanillin incorporated (0.1%, 0.5% and PMMA without vanillin as control). PMMA samples were coated with saliva. The adhesion assay was performed with C. albicans (ATCC 10231). The adherent yeast cells were stained with crystal violet and counted under microscope by random selection of 3 fields at 10X magnification. The statistical analyses performed by Kruskal Wallis and Mann Whitney non-parametric test. It was found that the PMMA resin samples with vanillin incorporation significantly reduced the adhesion of C. albicans as compared to the control group. This study indicates that vanillin incorporated resin can impede the adhesion of C. albicans to about 45 - 56 %. With further testing and development, vanillin can be employed as an antifungal agent to prevent adhesion of C. albicans to orthodontic self-curing PMMA resin.

Inhibitors of the glyoxylate cycle enzyme ICL1 in Candida albicans for potential use as antifungal agents.

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Hong-Leong Cheah

Full Text Available Candida albicans is an opportunistic pathogen that causes candidiasis in humans. In recent years, metabolic pathways in C. albicans have been explored as potential antifungal targets to treat candidiasis. The glyoxylate cycle, which enables C. albicans to survive in nutrient-limited host niches and its. Key enzymes (e.g., isocitrate lyase (ICL1, are particularly attractive antifungal targets for C. albicans. In this study, we used a new screening approach that better reflects the physiological environment that C. albicans cells experience during infection to identify potential inhibitors of ICL. Three compounds (caffeic acid (CAFF, rosmarinic acid (ROS, and apigenin (API were found to have antifungal activity against C. albicans when tested under glucose-depleted conditions. We further confirmed the inhibitory potential of these compounds against ICL using the ICL enzyme assay. Lastly, we assessed the bioavailability and toxicity of these compounds using Lipinski's rule-of-five and ADMET analysis.

Antifungal Activity of Commercial Essential Oils and Biocides against Candida Albicans.

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Serra, Elisa; Hidalgo-Bastida, Lilia Araida; Verran, Joanna; Williams, David; Malic, Sladjana

2018-01-25

Management of oral candidosis, most frequently caused by Candida albicans , is limited due to the relatively low number of antifungal drugs and the emergence of antifungal tolerance. In this study, the antifungal activity of a range of commercial essential oils, two terpenes, chlorhexidine and triclosan was evaluated against C. albicans in planktonic and biofilm form. In addition, cytotoxicity of the most promising compounds was assessed using murine fibroblasts and expressed as half maximal inhibitory concentrations (IC50). Antifungal activity was determined using a broth microdilution assay. The minimum inhibitory concentration (MIC) was established against planktonic cells cultured in a range of concentrations of the test agents. The minimal biofilm eradication concentration (MBEC) was determined by measuring re-growth of cells after pre-formed biofilm was treated for 24 h with the test agents. All tested commercial essential oils demonstrated anticandidal activity (MICs from 0.06% ( v / v ) to 0.4% ( v / v )) against planktonic cultures, with a noticeable increase in resistance exhibited by biofilms (MBECs > 1.5% ( v / v )). The IC50s of the commercial essential oils were lower than the MICs, while a one hour application of chlorhexidine was not cytotoxic at concentrations lower than the MIC. In conclusion, the tested commercial essential oils exhibit potential as therapeutic agents against C. albicans , although host cell cytotoxicity is a consideration when developing these new treatments.

Proper Sterol Distribution Is Required for Candida albicans Hyphal Formation and Virulence

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McCourt, Paula; Liu, Hsing-Yin; Parker, Josie E.; Gallo-Ebert, Christina; Donigan, Melissa; Bata, Adam; Giordano, Caroline; Kelly, Steven L.; Nickels, Joseph T.

2016-01-01

Candida albicans is an opportunistic fungus responsible for the majority of systemic fungal infections. Multiple factors contribute to C. albicans pathogenicity. C. albicans strains lacking CaArv1 are avirulent. Arv1 has a conserved Arv1 homology domain (AHD) that has a zinc-binding domain containing two cysteine clusters. Here, we explored the role of the CaAHD and zinc-binding motif in CaArv1-dependent virulence. Overall, we found that the CaAHD was necessary but not sufficient for cells to be virulent, whereas the zinc-binding domain was essential, as Caarv1/Caarv1 cells expressing the full-length zinc-binding domain mutants, Caarv1C3S and Caarv1C28S, were avirulent. Phenotypically, we found a direct correlation between the avirulence of Caarv1/Caarv1, Caarrv1AHD, Caarv1C3S, and Caarv1C28S cells and defects in bud site selection, septa formation and localization, and hyphal formation and elongation. Importantly, all avirulent mutant strains lacked the ability to maintain proper sterol distribution. Overall, our results have established the importance of the AHD and zinc-binding domain in fungal invasion, and have correlated an avirulent phenotype with the inability to maintain proper sterol distribution. PMID:27587298

Proper Sterol Distribution Is Required for Candida albicans Hyphal Formation and Virulence

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Paula McCourt

2016-11-01

Full Text Available Candida albicans is an opportunistic fungus responsible for the majority of systemic fungal infections. Multiple factors contribute to C. albicans pathogenicity. C. albicans strains lacking CaArv1 are avirulent. Arv1 has a conserved Arv1 homology domain (AHD that has a zinc-binding domain containing two cysteine clusters. Here, we explored the role of the CaAHD and zinc-binding motif in CaArv1-dependent virulence. Overall, we found that the CaAHD was necessary but not sufficient for cells to be virulent, whereas the zinc-binding domain was essential, as Caarv1/Caarv1 cells expressing the full-length zinc-binding domain mutants, Caarv1C3S and Caarv1C28S, were avirulent. Phenotypically, we found a direct correlation between the avirulence of Caarv1/Caarv1, Caarrv1AHD, Caarv1C3S, and Caarv1C28S cells and defects in bud site selection, septa formation and localization, and hyphal formation and elongation. Importantly, all avirulent mutant strains lacked the ability to maintain proper sterol distribution. Overall, our results have established the importance of the AHD and zinc-binding domain in fungal invasion, and have correlated an avirulent phenotype with the inability to maintain proper sterol distribution.

Brassinosteroid Mediated Cell Wall Remodeling in Grasses under Abiotic Stress

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Xiaolan Rao

2017-05-01

Full Text Available Unlike animals, plants, being sessile, cannot escape from exposure to severe abiotic stresses such as extreme temperature and water deficit. The dynamic structure of plant cell wall enables them to undergo compensatory changes, as well as maintain physical strength, with changing environments. Plant hormones known as brassinosteroids (BRs play a key role in determining cell wall expansion during stress responses. Cell wall deposition differs between grasses (Poaceae and dicots. Grass species include many important food, fiber, and biofuel crops. In this article, we focus on recent advances in BR-regulated cell wall biosynthesis and remodeling in response to stresses, comparing our understanding of the mechanisms in grass species with those in the more studied dicots. A more comprehensive understanding of BR-mediated changes in cell wall integrity in grass species will benefit the development of genetic tools to improve crop productivity, fiber quality and plant biomass recalcitrance.

Assembly and enlargement of the primary cell wall in plants

Science.gov (United States)

Cosgrove, D. J.

1997-01-01

Growing plant cells are shaped by an extensible wall that is a complex amalgam of cellulose microfibrils bonded noncovalently to a matrix of hemicelluloses, pectins, and structural proteins. Cellulose is synthesized by complexes in the plasma membrane and is extruded as a self-assembling microfibril, whereas the matrix polymers are secreted by the Golgi apparatus and become integrated into the wall network by poorly understood mechanisms. The growing wall is under high tensile stress from cell turgor and is able to enlarge by a combination of stress relaxation and polymer creep. A pH-dependent mechanism of wall loosening, known as acid growth, is characteristic of growing walls and is mediated by a group of unusual wall proteins called expansins. Expansins appear to disrupt the noncovalent bonding of matrix hemicelluloses to the microfibril, thereby allowing the wall to yield to the mechanical forces generated by cell turgor. Other wall enzymes, such as (1-->4) beta-glucanases and pectinases, may make the wall more responsive to expansin-mediated wall creep whereas pectin methylesterases and peroxidases may alter the wall so as to make it resistant to expansin-mediated creep.

The Cell Wall of Bacillus subtilis

NARCIS (Netherlands)

Scheffers, Dirk-Jan; Graumann, Peter

2012-01-01

The cell wall of Bacillus subtilis is a rigid structure on the outside of the cell that forms the first barrier between the bacterium and the environment, and at the same time maintains cell shape and withstands the pressure generated by the cell’s turgor. In this chapter, the chemical composition

Reduced CX3CL1 secretion contributes to the susceptibility of oral leukoplakia-associated fibroblasts to Candida albicans

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Ran Cheng

2016-11-01

Full Text Available Candida leukoplakia (OLK is a kind of oral leukoplakia combined with chronic candidal infection, which plays an important role in the malignant transformation of OLK. However, little is known about the etiology, including susceptibility of leukoplakia to candidal adhesion, invasion and infection. Some antimicrobial peptides secreted by oral epithelial cells or fibroblasts potentially have antifungal activities against Candida albicans (C. albicans. In this study, we established three co-culture models to simulate different C. albicans-fibroblasts interactions during progression of candida leukoplakia. The susceptibility of oral leukoplakia-associated fibroblasts (LKAFs to C. albicans and its underlying mechanism were determined. Samples of 14 LKAFs and 10 normal fibroblasts (NFs were collected. The co-culture models showed that LKAFs had promoted the adhesion, invasion, and survival of C. albicans compared with NFs. CX3CL1, a chemokine with antifungal activity, was less abundant in LKAFs than NFs. Overexpression of CX3CL1 via transfection in LKAFs could partly restore the resistance to C. albicans. We also showed that inhibition of ERK could suppress CX3CL1 secretion. While phosphor-ERK was inhibited in LKAFs compared with NFs. Besides, the expression of a shedding enzyme for CX3CL1, disintegrin and metalloproteinase domain (ADAM 17 was decreased in LKAFs than NFs. In conclusion, LKAFs produced and secreted less CX3CL1 by inhibiting the ERK signaling pathway, thereby contributing to impaired cell resistance to C. albicans.

The Cell Wall-Associated Proteins in the Dimorphic Pathogenic Species of Paracoccidioides.

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Puccia, Rosana; Vallejo, Milene C; Longo, Larissa V G

2017-01-01

Paracoccidioides brasiliensis and P. lutzii cause human paracoccidioidomycosis (PCM). They are dimorphic ascomycetes that grow as filaments at mild temperatures up to 28oC and as multibudding pathogenic yeast cells at 37oC. Components of the fungal cell wall have an important role in the interaction with the host because they compose the cell outermost layer. The Paracoccidioides cell wall is composed mainly of polysaccharides, but it also contains proportionally smaller rates of proteins, lipids, and melanin. The polysaccharide cell wall composition and structure of Paracoccidioides yeast cells, filamentous and transition phases were studied in detail in the past. Other cell wall components have been better analyzed in the last decades. The present work gives to the readers a detailed updated view of cell wall-associated proteins. Proteins that have been localized at the cell wall compartment using antibodies are individually addressed. We also make an overview about PCM, the Paracoccidioides cell wall structure, secretion mechanisms, and fungal extracellular vesicles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Daya hambat xylitol dan nistation terhadap pertumbuhan Candida albicans (in vitro (Inhibition effect of xylitol and nistatin combination on Candida albicans growth (in vitro

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Sarah Kartimah Djajusman

2014-09-01

Full Text Available Background: The growth of Candida albicans can be controlled by using antifungal such as nystatin. These days we found that using antifungal is not enough to control Candida albicans, we also have to control the intake of sugar by using xylitol. Purpose: Purpose of the study was to determine the optimal inhibitory concentration of xylitol-nystatin in the Candida albicans growth. Methods: This was an in-vitro study using an antimicrobial test of serial dilution with xylitol-nystatin and sucrose–nystatin consentration of 1%, 3%, 5%, 7%, 9%, and 10%.Growth inhibition of C. albicans was determined by the inhibition zone of xylitol + nystatin on C. albicans culture media (in vitro Results: The result of study was the inhibitory consentration of xylitol-nystatin to inhibit Candida albicans growth was 3%-10%. Conclusion: The study showed that combination of xylitol and nystation could inhibit the growth of Candida albicans.Latar belakang: Pertumbuhan Candida albicans dapat dikontrol dengan menggunakan antijamur seperti nistatin. Penggunakan antijamur saja tidak cukup untuk mengontrol Candida albicans, namun perlu pula mengontrol asupan gula dengan menggunakan xylitol. Tujuan: Tujuan dari penelitian ini adalah untuk menentukan konsentrasi hambat optimal xylitol-nistatin dalam pertumbuhan Candida albicans. Metode: Penelitian ini merupakan penelitian in vitro menggunakan uji antimikroba pengenceran serial dengan xylitol-nistatin dan nystatin-sukrosa konsentrasi 1%, 3 %, 5 %, 7%, 9%, dan 10%. Daya hambat pertumbuhan C. albicans diukur dari zona hambat xylitol + nistatin pada media kultur C. albicans (in vitro Hasil: Konsentrasi penghambatan xylitol-nistatin untuk menghambat pertumbuhan Candida albicans adalah 3-10%. Simpulan: Hasil penelitian menunjukkan bahwa kombinasi xylitol dan nystation bisa menghambat pertumbuhan Candida albicans.

Employing proteomic analysis to compare Paracoccidioides lutzii yeast and mycelium cell wall proteins.

Science.gov (United States)

Araújo, Danielle Silva; de Sousa Lima, Patrícia; Baeza, Lilian Cristiane; Parente, Ana Flávia Alves; Melo Bailão, Alexandre; Borges, Clayton Luiz; de Almeida Soares, Célia Maria

2017-11-01

Paracoccidioidomycosis is an important systemic mycosis caused by thermodimorphic fungi of the Paracoccidioides genus. During the infective process, the cell wall acts at the interface between the fungus and the host. In this way, the cell wall has a key role in growth, environment sensing and interaction, as well as morphogenesis of the fungus. Since the cell wall is absent in mammals, it may present molecules that are described as target sites for new antifungal drugs. Despite its importance, up to now few studies have been conducted employing proteomics in for the identification of cell wall proteins in Paracoccidioides spp. Here, a detailed proteomic approach, including cell wall-fractionation coupled to NanoUPLC-MS E , was used to study and compare the cell wall fractions from Paracoccidioides lutzii mycelia and yeast cells. The analyzed samples consisted of cell wall proteins extracted by hot SDS followed by extraction by mild alkali. In summary, 512 proteins constituting different cell wall fractions were identified, including 7 predicted GPI-dependent cell wall proteins that are potentially involved in cell wall metabolism. Adhesins previously described in Paracoccidioides spp. such as enolase, glyceraldehyde-3-phosphate dehydrogenase were identified. Comparing the proteins in mycelium and yeast cells, we detected some that are common to both fungal phases, such as Ecm33, and some specific proteins, as glucanase Crf1. All of those proteins were described in the metabolism of cell wall. Our study provides an important elucidation of cell wall composition of fractions in Paracoccidioides, opening a way to understand the fungus cell wall architecture. Copyright © 2017 Elsevier B.V. All rights reserved.

Advanced technologies for plant cell wall evolution and diversity

DEFF Research Database (Denmark)

Fangel, Jonatan Ulrik

Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotides...... cannot really be synthesised or sequenced. The work described in this thesis is focused to a large extent on the development of a microarray-based high-throughput method for cell wall analysis known as Comprehensive microarray polymer profiling or CoMPP. The procedure uses highly specific molecular...... probes (monoclonal antibodies mAbs and carbohydrate binding modules, CBMs) to rapidly profile polysaccharides across a sample set. During my PhD I have further developed the CoMPP technique and used it for cell wall analysis within the context of a variety of applied and fundamental projects. The data...

C. albicans growth, transition, biofilm formation, and gene expression modulation by antimicrobial decapeptide KSL-W

Science.gov (United States)

2013-01-01

Background Antimicrobial peptides have been the focus of much research over the last decade because of their effectiveness and broad-spectrum activity against microbial pathogens. These peptides also participate in inflammation and the innate host defense system by modulating the immune function that promotes immune cell adhesion and migration as well as the respiratory burst, which makes them even more attractive as therapeutic agents. This has led to the synthesis of various antimicrobial peptides, including KSL-W (KKVVFWVKFK-NH2), for potential clinical use. Because this peptide displays antimicrobial activity against bacteria, we sought to determine its antifungal effect on C. albicans. Growth, hyphal form, biofilm formation, and degradation were thus examined along with EFG1, NRG1, EAP1, HWP1, and SAP 2-4-5-6 gene expression by quantitative RT-PCR. Results This study demonstrates that KSL-W markedly reduced C. albicans growth at both early and late incubation times. The significant effect of KSL-W on C. albicans growth was observed beginning at 10 μg/ml after 5 h of contact by reducing C. albicans transition and at 25 μg/ml by completely inhibiting C. albicans transition. Cultured C. albicans under biofilm-inducing conditions revealed that both KSL-W and amphotericin B significantly decreased biofilm formation at 2, 4, and 6 days of culture. KSL-W also disrupted mature C. albicans biofilms. The effect of KSL-W on C. albicans growth, transition, and biofilm formation/disruption may thus occur through gene modulation, as the expression of various genes involved in C. albicans growth, transition and biofilm formation were all downregulated when C. albicans was treated with KSL-W. The effect was greater when C. albicans was cultured under hyphae-inducing conditions. Conclusions These data provide new insight into the efficacy of KSL-W against C. albicans and its potential use as an antifungal therapy. PMID:24195531

Alfalfa stem tissues: Cell wall deposition, composition, and degradability

NARCIS (Netherlands)

Jung, H.G.; Engels, F.M.

2002-01-01

Declining cell wall degradability of alfalfa (Medicago sativa L.) stems with maturation limits the nutritional value of alfalfa for ruminants. This study characterized changes in cell wall concentration, composition, and degradability by rumen microbes resulting from alfalfa stem tissue

Competitive Interactions between C. albicans, C. glabrata and C. krusei during Biofilm Formation and Development of Experimental Candidiasis

Science.gov (United States)

Rossoni, Rodnei Dennis; Barbosa, Júnia Oliveira; Vilela, Simone Furgeri Godinho; dos Santos, Jéssica Diane; de Barros, Patrícia Pimentel; Prata, Márcia Cristina de Azevedo; Anbinder, Ana Lia; Fuchs, Beth Burgwyn; Jorge, Antonio Olavo Cardoso; Mylonakis, Eleftherios; Junqueira, Juliana Campos

2015-01-01

In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis. PMID:26146832

Competitive Interactions between C. albicans, C. glabrata and C. krusei during Biofilm Formation and Development of Experimental Candidiasis.

Science.gov (United States)

Rossoni, Rodnei Dennis; Barbosa, Júnia Oliveira; Vilela, Simone Furgeri Godinho; dos Santos, Jéssica Diane; de Barros, Patrícia Pimentel; Prata, Márcia Cristina de Azevedo; Anbinder, Ana Lia; Fuchs, Beth Burgwyn; Jorge, Antonio Olavo Cardoso; Mylonakis, Eleftherios; Junqueira, Juliana Campos

2015-01-01

In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis.

Expression of S-adenosylmethionine Hydrolase in Tissues Synthesizing Secondary Cell Walls Alters Specific Methylated Cell Wall Fractions and Improves Biomass Digestibility

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Aymerick Eudes

2016-07-01

Full Text Available Plant biomass is a large source of fermentable sugars for the synthesis of bioproducts using engineered microbes. These sugars are stored as cell wall polymers, mainly cellulose and hemicellulose, and are embedded with lignin, which makes their enzymatic hydrolysis challenging. One of the strategies to reduce cell wall recalcitrance is the modification of lignin content and composition. Lignin is a phenolic polymer of methylated aromatic alcohols and its synthesis in tissues developing secondary cell walls is a significant sink for the consumption of the methyl donor S-adenosylmethionine (AdoMet. In this study, we demonstrate in Arabidopsis stems that targeted expression of S-adenosylmethionine hydrolase (AdoMetase, E.C. 3.3.1.2 in secondary cell-wall synthesizing tissues reduces the AdoMet pool and impacts lignin content and composition. In particular, both NMR analysis and pyrolysis gas chromatography mass spectrometry of lignin in engineered biomass showed relative enrichment of non-methylated p-hydroxycinnamyl (H units and a reduction of dimethylated syringyl (S units. This indicates a lower degree of methylation compared to that in wild-type lignin. Quantification of cell wall-bound hydroxycinnamates revealed a reduction of ferulate in AdoMetase transgenic lines. Biomass from transgenic lines, in contrast to that in control plants, exhibits an enrichment of glucose content and a reduction in the degree of hemicellulose glucuronoxylan methylation. We also show that these modifications resulted in a reduction of cell wall recalcitrance, because sugar yield generated by enzymatic biomass saccharification was greater than that of wild type plants. Considering that transgenic plants show no important diminution of biomass yields, and that heterologous expression of AdoMetase protein can be spatiotemporally optimized, this novel approach provides a valuable option for the improvement of lignocellulosic biomass feedstock.