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A developmental stage of hyphal cells shows riboflavin overproduction instead of sporulation in Ashbya gossypii. Appl Microbiol Biotechnol 2013; 97:10143-53. [DOI: 10.1007/s00253-013-5266-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/11/2022]
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Arias P, Díez-Muñiz S, García R, Nombela C, Rodríguez-Peña JM, Arroyo J. Genome-wide survey of yeast mutations leading to activation of the yeast cell integrity MAPK pathway: novel insights into diverse MAPK outcomes. BMC Genomics 2011; 12:390. [PMID: 21810245 PMCID: PMC3167797 DOI: 10.1186/1471-2164-12-390] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 08/02/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The yeast cell wall integrity mitogen-activated protein kinase (CWI-MAPK) pathway is the main regulator of adaptation responses to cell wall stress in yeast. Here, we adopt a genomic approach to shed light on two aspects that are only partially understood, namely, the characterization of the gene functional catalog associated with CWI pathway activation and the extent to which MAPK activation correlates with transcriptional outcomes. RESULTS A systematic yeast mutant deletion library was screened for constitutive transcriptional activation of the CWI-related reporter gene MLP1. Monitoring phospho-Slt2/Mpk1 levels in the identified mutants revealed sixty-four deletants with high levels of phosphorylation of this MAPK, including mainly genes related to cell wall construction and morphogenesis, signaling, and those with unknown function. Phenotypic analysis of the last group of mutants suggests their involvement in cell wall homeostasis. A good correlation between levels of Slt2 phosphorylation and the magnitude of the transcriptional response was found in most cases. However, the expression of CWI pathway-related genes was enhanced in some mutants in the absence of significant Slt2 phosphorylation, despite the fact that functional MAPK signaling through the pathway was required. CWI pathway activation was associated to increased deposition of chitin in the cell wall - a known survival compensatory mechanism - in about 30% of the mutants identified. CONCLUSION We provide new insights into yeast genes related to the CWI pathway and into how the state of activation of the Slt2 MAPK leads to different outcomes, discovering the versatility of this kind of signaling pathways. These findings potentially have broad implications for understanding the functioning of other eukaryotic MAPKs.
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Affiliation(s)
- Patricia Arias
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, IRYCIS, 28040 Madrid, Spain
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Rüchel R, Schaffrinski M, Seshan KR, Cole GT. Vital staining of fungal elements in deep-seated mycotic lesions during experimental murine mycoses using the parenterally applied optical brightener Blankophor. Med Mycol 2000; 38:231-7. [PMID: 10892992 DOI: 10.1080/mmy.38.3.231.237] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Optical brighteners of the diaminostilbene type are fluorescent dyes which are popular diagnostic tools in the mycology laboratory. While these dyes are conventionally used for the in vitro diagnosis of mycoses, their low toxicity and chemical reactivity have led us to investigate their potential use for in vivo staining of fungal elements in mycotic tissue. In mice we have established deep-seated candidiasis, cryptococcosis, aspergillosis and zygomycosis, as well as coccidioidomycosis, histoplasmosis and blastomycosis. After establishment of infection, which mostly required immunosuppression, a single dose of 100 microl of an aqueous solution (2.2 x 10(-4) M) of the optical brightener Blankophor P fluessig (4,4'-Bis [(4-anilino-6-substituted-1,3,5-triazine-2-yl) amino] stilbene-2,2'-disulfonic acid) was injected by the tail vein and the animals were sacrificed 1 h later. Sections of freshly prepared target organs were directly subjected to epifluorescence microscopy using an appropriate filter kit. In most cases, fluorescent fungal elements could be detected in the murine tissue. There was little evidence for uptake of the dye by non-infected tissues. It is suggested that radioactive labeling may render parenteral Blankophor suitable for radiographic localization of deep-seated mycotic foci in the host.
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Affiliation(s)
- R Rüchel
- University of Göttingen, Faculty of Medicine, Department of Bacteriology, Germany.
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Braun PC. Nutrient uptake byCandida albicans: the influence of cell surface mannoproteins. Can J Microbiol 1999. [DOI: 10.1139/w99-035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Numerous ultrastructural and biochemical analyses have been performed to characterize the cell wall composition and structure of Candida albicans. However, little investigation has focused on how subtle differences in cell wall structure influence the intracellular transport of amino acids and monosaccharides. In this study C. albicans 4918 and ATCC 10231 were grown in culture conditions capable of modifying surface mannoproteins and induced surface hydrophobic or hydrophilic yeast cell wall states. Subcultures of these hydrophobic and hydrophilic yeasts were subsequently incubated with one of seven L-[3H] amino acids: glycine, leucine, proline, serine, aspartic acid, lysine, or arginine. The transport of [3H] mannose and [3H] N-acetyl-D-glucosamine were also investigated. This study revealed significant strain differences (P [Formula: see text] 0.05) between hydrophilic and hydrophobic yeast transport of these nutrients throughout a 2 h incubation. Hydrophilic cultures of 4918 and ATCC 10231 transported nearly two times more (pmol mg-1dry weight) proline, mannose, and N-acetyl-D-glucosamine than hydrophobic yeast. Hydrophobic cultures preferentially incorporated serine and aspartic acid in both these strains. Strain variation was indicated with the transport of leucine, lysine, and arginine, as follows: experiments showed that hydrophilic 4918 cultures selectively transported leucine, lysine, and arginine, whereas, the hydrophobic ATCC 10231 cultures incorporated these amino acids.Key words: Candida albicans, mannoproteins, amino acid transport.
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Vardar-Unlü G, McSharry C, Douglas LJ. Fucose-specific adhesins on germ tubes of Candida albicans. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1998; 20:55-67. [PMID: 9514576 DOI: 10.1111/j.1574-695x.1998.tb01111.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Lectin-like adhesins of hyphal-form Candida albicans were investigated by conventional fluorescence microscopy, fluorescence microscopy with image analysis, spectrofluorimetry and flow cytometry. Labelling was done with neoglycoprotein probes consisting of sugars (fucose, mannose, glucose, galactose, lactose) covalently linked to bovine serum albumin (BSA), which itself was labelled with fluorescein. The fucose probe bound to both the yeast and germ-tube portions of hyphal-form cells, not especially at the tip, but in the adjacent region of the germ-tube portion. Probes with the other sugars did not label the hyphal-form cells. Fucose-probe binding to the cells was optimal at pH 5.0 in citrate buffer, and was a time-dependent reaction requiring 30-60 min and reaching saturation concentration at 100 microg ml(-1). Each hyphal-form cell of C. albicans grown in 199 medium was calculated to have about 2 x 10(7) fucose probe-binding sites. There appeared to be no requirement for Ca2+ or Mg2+ in binding. Binding of the fucose probe to the hyphal-form cells was higher at 37 degrees C than at 22 degrees C or 4 degrees C. Fluorescence intensity of the fucose-labelled yeast forms was not increased over the hyphal-form cells. A germ-tube-deficient mutant when exposed to hyphal-form growth conditions for 2 h showed much less binding of the fucose probe than the wild-type which produced germ tubes. Confirmation of specificity and the need for a carrier molecule was obtained by showing that Fuc-BSA (without fluorescein) effectively inhibited the binding of the fucose probe, although L-fucose itself was inactive, as was Gal-BSA.
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Affiliation(s)
- G Vardar-Unlü
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, UK.
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Rico H, Carrillo C, Aguado C, Mormeneo S, Sentandreu R. Initial steps of wall protoplast regeneration in Candida albicans. Res Microbiol 1997; 148:593-603. [PMID: 9765844 DOI: 10.1016/s0923-2508(97)88083-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell wall regeneration of individual Candida albicans yeast and mycelial protoplasts was studied with confocal and electron microscopy using polyclonal antibodies and lectins. Quantitative measurements of the fluorescence emitted by individual protoplasts during the process of regeneration indicate that chitin is the first polymer to be laid down, whereas beta (1,3)- and beta (1,6)glucan are incorporated at a later stage. Mannoproteins were found on the surface of fresh protoplasts and those newly synthesized were then deposited with time. During the first steps of wall regeneration, the proteins that interacted covalently with chitin or glucan were different, but the same species were found linked to each polymer in yeast and mycelial regenerating forms. The aggregates formed by regenerating protoplasts were shown to be due to the chitin and mannoprotein network initially laid.
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Affiliation(s)
- H Rico
- Sección de Microbiología, Facultad de Farmacia, Universidad de Valencia, Spain
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Segal E, Gottlieb S, Altboum Z, Gov Y, Berdicevsky I. Adhesion of Candida albicans to epithelial cells--effect of nikkomycin. Mycoses 1997; 40:33-9. [PMID: 9260479 DOI: 10.1111/j.1439-0507.1997.tb00168.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study investigated the effect of the chitin synthetase inhibitors, the nikkomycins (NZ and NZ+NX), on Candida albicans adhesion to buccal epithelial cells (BECs) in vitro. The effect was expressed in reduced chitin synthetase activity and chitin content of fungal cells. In vitro adhesion assays to BECs of Candida exposed to NZ and NZ+NX revealed reduced adhesion values. Light, scanning and transmission electron microscopy (SEM, TEM) of NZ-treated and untreated micro-organisms showed changed fungal morphology and reduced adherence of the treated yeasts. Scanning electron microscopy of NZ-treated C. albicans labelled with gold-conjugated wheatgerm agglutinin (WGA) revealed less labelling than in the untreated organisms. A close contact between the fungus and the epithelial cell at a site with intense WGA-gold labelling was noted in TEM experiments. The data point to the involvement of chitin in the adhesion of C. albicans to epithelial cells.
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Affiliation(s)
- E Segal
- Department of Human Microbiology, Sackler School of Medicine, Tel Aviv University, Israel
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Wenisch C, Linnau KF, Parschalk B, Zedtwitz-Liebenstein K, Georgopoulos A. Rapid susceptibility testing of fungi by flow cytometry using vital staining. J Clin Microbiol 1997; 35:5-10. [PMID: 8968873 PMCID: PMC229504 DOI: 10.1128/jcm.35.1.5-10.1997] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A 1-h assay for antifungal susceptibility testing measuring the impairment of fungal metabolic activity was developed. Yeast viability was analyzed by flow cytometry with a novel fluorescent probe, FUN-1, which emits a red fluorescence when the yeast is metabolically active. For nine Candida albicans strains tested, this method yielded results comparable to those obtained by the standard M27 procedure for amphotericin B, flucytosine, fluconazole, and ketoconazole. Whether the flow cytometry antifungal susceptibility test results correlate with the in vivo activities of the drugs remains to determined.
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Affiliation(s)
- C Wenisch
- Department of Infectious Disease, Internal Medicine I, University Hospital of Vienna, Austria
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Green L, Petersen B, Steimel L, Haeber P, Current W. Rapid determination of antifungal activity by flow cytometry. J Clin Microbiol 1994; 32:1088-91. [PMID: 8027319 PMCID: PMC267192 DOI: 10.1128/jcm.32.4.1088-1091.1994] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have developed a rapid assay of antifungal activity which utilizes flow cytometry to detect accumulation of a vital dye in drug-damaged fungal cells. Results of these studies suggest that flow cytometry may provide an improved, rapid method for determining and comparing the antifungal activities of compounds with differing modes of action.
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Affiliation(s)
- L Green
- Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46202
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Lynch M, Kukuruga M, Nakeff A, Fidel P, Sobel J. Flow cytometric analysis of germ tube formation inCandida albicans. Med Mycol 1993. [DOI: 10.1080/02681219380000471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Chapman T, Kinsman O, Houston J. Chitin biosynthesis in Candida albicans grown in vitro and in vivo and its inhibition by nikkomycin Z. Antimicrob Agents Chemother 1992; 36:1909-14. [PMID: 1416881 PMCID: PMC192208 DOI: 10.1128/aac.36.9.1909] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An N-acetyl-D-[14C]glucosamine radiolabel incorporation assay has been used to monitor chitin biosynthesis in whole cells of Candida albicans both in vitro and in vivo in two different mouse infection models, one using the peritoneal cavity as a chamber in which to add and retrieve cells and the other using infected kidneys. Specific labeling of chitin in alkali-insoluble material was confirmed by chitinase digestion, analysis of acid hydrolysates, and the use of nikkomycin Z as a probe. Nikkomycin Z was shown to strongly inhibit chitin biosynthesis in C. albicans grown in vitro and in vivo in both models. This demonstrates that nikkomycin Z-susceptible chitin synthase activity is present in C. albicans when the fungus is in its pathogenic state in vivo. The limited use of nikkomycin as a therapeutic agent is discussed.
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Affiliation(s)
- T Chapman
- Division of Microbiology, Glaxo Group Research Ltd., Greenford, Middlesex, United Kingdom
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O'Gorman MR, Hopfer RL. Amphotericin B susceptibility testing of Candida species by flow cytometry. CYTOMETRY 1991; 12:743-7. [PMID: 1794254 DOI: 10.1002/cyto.990120808] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have developed an 8 hr flow cytometry (FCM) method for assessing susceptibility of yeasts to amphotericin B (AmpB). The method detects both high-level and relative-resistance to the drug. Variables found to affect fluorescence of control and AmpB treated cells included pH, presence of glucose, incubation conditions, concentration and length of exposure to both AmpB and ethidium bromide (ETBR), and the degree of resistance to AmpB. The FCM method was optimized based on increased red fluorescence intensity (RF), decreased forward angle light scatter (FALS), and a negative gating technique. A dose response was seen between 0.1 and 10 micrograms AmpB/ml for the susceptible control strain. Greater than 50% of cells from all susceptible strains tested transfer into the negative gate when exposed to 2.5 micrograms Amp B/ml while fewer than 5% of cells of the highly resistant C. tropicalis (ATCC 28707) are affected at concentrations up to 20 micrograms/ml. This method may provide a more accurate assessment of Amp B susceptibility than conventional tube dilution methods.
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Affiliation(s)
- M R O'Gorman
- Department of Hospital Laboratories, Clinical Microbiology and Immunology, UNC Hospitals, Chapel Hill 27514
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