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Francois JM, Formosa C, Schiavone M, Pillet F, Martin-Yken H, Dague E. Use of atomic force microscopy (AFM) to explore cell wall properties and response to stress in the yeast Saccharomyces cerevisiae. Curr Genet 2013; 59:187-96. [PMID: 24071902 DOI: 10.1007/s00294-013-0411-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/12/2013] [Accepted: 09/18/2013] [Indexed: 11/30/2022]
Abstract
Over the past 20 years, the yeast cell wall has been thoroughly investigated by genetic and biochemical methods, leading to remarkable advances in the understanding of its biogenesis and molecular architecture as well as to the mechanisms by which this organelle is remodeled in response to environmental stresses. Being a dynamic structure that constitutes the frontier between the cell interior and its immediate surroundings, imaging cell surface, measuring mechanical properties of cell wall or probing cell surface proteins for localization or interaction with external biomolecules are among the most burning questions that biologists wished to address in order to better understand the structure-function relationships of yeast cell wall in adhesion, flocculation, aggregation, biofilm formation, interaction with antifungal drugs or toxins, as well as response to environmental stresses, such as temperature changes, osmotic pressure, shearing stress, etc. The atomic force microscopy (AFM) is nowadays the most qualified and developed technique that offers the possibilities to address these questions since it allows working directly on living cells to explore and manipulate cell surface properties at nanometer resolution and to analyze cell wall proteins at the single molecule level. In this minireview, we will summarize the most recent contributions made by AFM in the analysis of the biomechanical and biochemical properties of the yeast cell wall and illustrate the power of this tool to unravel unexpected effects caused by environmental stresses and antifungal agents on the surface of living yeast cells.
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Affiliation(s)
- Jean Marie Francois
- Université de Toulouse, INSA, UPS, INP, 135 avenue de Rangueil, 31077, Toulouse, France,
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352
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Samuelsen ABC, Schrezenmeir J, Knutsen SH. Effects of orally administered yeast-derived beta-glucans: a review. Mol Nutr Food Res 2013; 58:183-93. [PMID: 24019098 DOI: 10.1002/mnfr.201300338] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/01/2013] [Accepted: 07/20/2013] [Indexed: 01/01/2023]
Abstract
Yeast-derived beta-glucans (Y-BG) are considered immunomodulatory compounds suggested to enhance the defense against infections and exert anticarcinogenic effects. Specific preparations have received Generally Recognized as Safe status and acceptance as novel food ingredients by European Food Safety Authority. In human trials, orally administered Y-BG significantly reduced the incidence of upper respiratory tract infections in individuals susceptible to upper respiratory tract infections, whereas significant differences were not seen in healthy individuals. Increased salivary IgA in healthy individuals, increased IL-10 levels in obese subjects, beneficial changes in immunological parameters in allergic patients, and activated monocytes in cancer patients have been reported following Y-BG intake. The studies were conducted with different doses (7.5-1500 mg/day), using different preparations that vary in their primary structure, molecular weight, and solubility. In animal models, oral Y-BG have reduced the incidence of bacterial infections and levels of stress-induced cytokines and enhanced antineoplastic effects of cytotoxic agents. Protective effects toward drug intoxication and ischemia/reperfusion injury have also been reported. In conclusion, additional studies following good clinical practice principles are needed in which well-defined Y-BG preparations are used and immune markers and disease endpoints are assessed. Since optimal dosing may depend on preparation characteristics, dose-response curves might be assessed to find the optimal dose for a specific preparation.
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Affiliation(s)
- Anne Berit C Samuelsen
- Department of Pharmaceutical Chemistry, Pharmacognosy, School of Pharmacy, University of Oslo, Oslo, Norway
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353
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Evidence for a structural role for acid-fast lipids in oocyst walls of Cryptosporidium, Toxoplasma, and Eimeria. mBio 2013; 4:e00387-13. [PMID: 24003177 PMCID: PMC3760245 DOI: 10.1128/mbio.00387-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Coccidia are protozoan parasites that cause significant human disease and are of major agricultural importance. Cryptosporidium spp. cause diarrhea in humans and animals, while Toxoplasma causes disseminated infections in fetuses and untreated AIDS patients. Eimeria is a major pathogen of commercial chickens. Oocysts, which are the infectious form of Cryptosporidium and Eimeria and one of two infectious forms of Toxoplasma (the other is tissue cysts in undercooked meat), have a multilayered wall. Recently we showed that the inner layer of the oocyst walls of Toxoplasma and Eimeria is a porous scaffold of fibers of β-1,3-glucan, which are also present in fungal walls but are absent from Cryptosporidium oocyst walls. Here we present evidence for a structural role for lipids in the oocyst walls of Cryptosporidium, Toxoplasma, and Eimeria. Briefly, oocyst walls of each organism label with acid-fast stains that bind to lipids in the walls of mycobacteria. Polyketide synthases similar to those that make mycobacterial wall lipids are abundant in oocysts of Toxoplasma and Eimeria and are predicted in Cryptosporidium. The outer layer of oocyst wall of Eimeria and the entire oocyst wall of Cryptosporidium are dissolved by organic solvents. Oocyst wall lipids are complex mixtures of triglycerides, some of which contain polyhydroxy fatty acyl chains like those present in plant cutin or elongated fatty acyl chains like mycolic acids. We propose a two-layered model of the oocyst wall (glucan and acid-fast lipids) that resembles the two-layered walls of mycobacteria (peptidoglycan and acid-fast lipids) and plants (cellulose and cutin). Oocysts, which are essential for the fecal-oral spread of coccidia, have a wall that is thought responsible for their survival in the environment and for their transit through the stomach and small intestine. While oocyst walls of Toxoplasma and Eimeria are strengthened by a porous scaffold of fibrils of β-1,3-glucan and by proteins cross-linked by dityrosines, both are absent from walls of Cryptosporidium. We show here that all oocyst walls are acid fast, have a rigid bilayer, dissolve in organic solvents, and contain a complex set of triglycerides rich in polyhydroxy and long fatty acyl chains that might be synthesized by an abundant polyketide synthase. These results suggest the possibility that coccidia build a waxy coat of acid-fast lipids in the oocyst wall that makes them resistant to environmental stress.
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354
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Identification of a novel chitin-binding spore wall protein (NbSWP12) with a BAR-2 domain from Nosema bombycis (microsporidia). Parasitology 2013; 140:1394-402. [PMID: 23920053 DOI: 10.1017/s0031182013000875] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The spore wall of Nosema bombycis plays an important role in microsporidian pathogenesis. Protein fractions from germinated spore coats were analysed by two-dimensional polyacrylamide gel electrophoresis and MALDI-TOF/TOF mass spectrometry. Three protein spots were identified as the hypothetical spore wall protein NbHSWP12. A BAR-2 domain (e-value: 1.35e-03) was identified in the protein, and an N-terminal protein-heparin interaction motif, a potential N-glycosylation site, and 16 phosphorylation sites primarily activated by protein kinase C were also predicted. The sequence analysis suggested that Nbhswp12 and its homologous genes are widely distributed among microsporidia. Additionally, Nbhswp12 gene homologues share similar sequence features. An indirect immunofluorescence analysis showed that NbHSWP12 localized to the spore wall, and thus we renamed it spore wall protein 12 (NbSWP12). Moreover, NbSWP12 could adhere to deproteinized N. bombycis chitin coats that were obtained by hot alkaline treatment. This novel N. bombycis spore wall protein may function in a structural capacity to facilitate microsporidial spore maintenance.
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355
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Li+ effect on the cell wall of the yeast Saccharomyces cerevisiae as probed by FT-IR spectroscopy. Open Life Sci 2013. [DOI: 10.2478/s11535-013-0186-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe effect of Li+ ions as a transformation inducing agent on the yeast cell wall has been studied. Two Saccharomyces cerevisiae strains, p63-DC5 with a native cell wall, and strain XCY42-30D(mnn1) which contains structural changes in the mannan-protein complex, were used. Fourier transform infrared (FT-IR) spectroscopy has been used for the characterization of the yeast strains and for determination of the effect of lithium cations on the cell wall. A comparison of the carbohydrate absorption band positions in the 970–1185 cm−1 range, of Na+ and Li+ treated yeast cells has been estimated. Absorption band positions of the cell wall carbohydrates of p63-DC5 were not influenced by the studied ions. On the contrary, the treatment of XCY42-30D(mnn1) cells with Li+ ions shifted glucan band positions, implying that the cell wall structure of strain XCY42-30D(mnn1) is more sensitive to Li+ ion treatment.
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356
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Cruz S, Muñoz S, Manjón E, García P, Sanchez Y. The fission yeast cell wall stress sensor-like proteins Mtl2 and Wsc1 act by turning on the GTPase Rho1p but act independently of the cell wall integrity pathway. Microbiologyopen 2013; 2:778-94. [PMID: 23907979 PMCID: PMC3831639 DOI: 10.1002/mbo3.113] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/07/2013] [Accepted: 06/11/2013] [Indexed: 12/27/2022] Open
Abstract
Sensing stressful conditions that affect the cell wall reorganization is important for yeast survival. Here, we studied two proteins SpWsc1p and SpMtl2p with structural features indicative of plasma membrane-associated cell wall sensors. We found that Mtl2p and Wsc1p act by turning on the Rho1p GTPase. Each gene could be deleted individually without affecting viability, but the deletion of both was lethal and this phenotype was rescued by overexpression of the genes encoding either Rho1p or its GDP/GTP exchange factors (GEFs). In addition, wsc1Δ and mtl2Δ cells showed a low level of Rho1p-GTP under cell wall stress. Mtl2p-GFP (green fluorescent protein) localized to the cell periphery and was necessary for survival under different types of cell wall stress. Wsc1p-GFP was concentrated in patches at the cell tips, it interacted with the Rho-GEF Rgf2p, and its overexpression activated cell wall biosynthesis. Our results are consistent with the notion that cell wall assembly is regulated by two different networks involving Rho1p. One includes signaling from Mtl2p through Rho1p to Pck1p, while the second one implicates signaling from Wsc1p and Rgf2p through Rho1p to activate glucan synthase (GS). Finally, signaling through the mitogen-activated protein kinase (MAPK) Pmk1p remained active in mtl2Δ and wsc1Δ disruptants exposed to cell wall stress, suggesting that the cell wall stress-sensing spectrum of Schizosaccharomyces pombe sensor-like proteins differs from that of Saccharomyces cerevisiae.
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Affiliation(s)
- Sandra Cruz
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, C/Zacarías González s/n., Salamanca, Spain
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357
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Caballero-Lima D, Kaneva IN, Watton SP, Sudbery PE, Craven CJ. The spatial distribution of the exocyst and actin cortical patches is sufficient to organize hyphal tip growth. EUKARYOTIC CELL 2013; 12:998-1008. [PMID: 23666623 PMCID: PMC3697460 DOI: 10.1128/ec.00085-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/07/2013] [Indexed: 11/20/2022]
Abstract
In the hyphal tip of Candida albicans we have made detailed quantitative measurements of (i) exocyst components, (ii) Rho1, the regulatory subunit of (1,3)-β-glucan synthase, (iii) Rom2, the specialized guanine-nucleotide exchange factor (GEF) of Rho1, and (iv) actin cortical patches, the sites of endocytosis. We use the resulting data to construct and test a quantitative 3-dimensional model of fungal hyphal growth based on the proposition that vesicles fuse with the hyphal tip at a rate determined by the local density of exocyst components. Enzymes such as (1,3)-β-glucan synthase thus embedded in the plasma membrane continue to synthesize the cell wall until they are removed by endocytosis. The model successfully predicts the shape and dimensions of the hyphae, provided that endocytosis acts to remove cell wall-synthesizing enzymes at the subapical bands of actin patches. Moreover, a key prediction of the model is that the distribution of the synthase is substantially broader than the area occupied by the exocyst. This prediction is borne out by our quantitative measurements. Thus, although the model highlights detailed issues that require further investigation, in general terms the pattern of tip growth of fungal hyphae can be satisfactorily explained by a simple but quantitative model rooted within the known molecular processes of polarized growth. Moreover, the methodology can be readily adapted to model other forms of polarized growth, such as that which occurs in plant pollen tubes.
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Affiliation(s)
- David Caballero-Lima
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
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358
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Wang Y, Chi EY, Natvig DO, Schanze KS, Whitten DG. Antimicrobial activity of cationic conjugated polyelectrolytes and oligomers against Saccharomyces cerevisiae vegetative cells and ascospores. ACS APPLIED MATERIALS & INTERFACES 2013; 5:4555-61. [PMID: 23510401 DOI: 10.1021/am400220s] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The antifungal activities of poly(phenylene ethynylene) (PPE)-based cationic conjugated polyelectrolytes (CPEs) and oligo-phenylene ethynylenes (OPEs) were investigated using Saccharomyces cerevisiae (S. cerevisiae) as a model pathogen. The effect of the CPE and OPE materials on the vegetative cells and ascospores were tested in the dark or with UV-irradiation. A number of the tested polymers and oligomers significantly reduced the viability of the vegetative yeast cells in the dark, with activities exceeding the commonly used antibiotic Amphotericin B. With UV-irradiation, all of the tested CPEs and OPEs exhibited potent antifungal activities and completely inactivated the yeast cells. In particular, the oligomeric EO-OPE-1(Th, C2) strongly inactivates ascospores with UV-light at a dose level lower than sporicidal agents reported in the literature. Under conditions that promote spore germination, the CPEs and OPEs show efficient activities against the germinated spores. The protein-enriched outer envelope of yeast cells and germinated ascospores appears to serve as a main target for the CPE and OPE antimicrobial materials.
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Affiliation(s)
- Ying Wang
- Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131-1341, United States
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359
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El-Kirat-Chatel S, Beaussart A, Alsteens D, Sarazin A, Jouault T, Dufrêne YF. Single-molecule analysis of the major glycopolymers of pathogenic and non-pathogenic yeast cells. NANOSCALE 2013; 5:4855-4863. [PMID: 23615555 DOI: 10.1039/c3nr00813d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Most microbes are coated with carbohydrates that show remarkable structural variability and play a crucial role in mediating microbial-host interactions. Understanding the functions of cell wall glycoconjugates requires detailed knowledge of their molecular organization, diversity and heterogeneity. Here we use atomic force microscopy (AFM) with tips bearing specific probes (lectins, antibodies) to analyze the major glycopolymers of pathogenic and non-pathogenic yeast cells at molecular resolution. We show that non-ubiquitous β-1,2-mannans are largely exposed on the surface of native cells from pathogenic Candida albicans and C. glabrata, the former species displaying the highest glycopolymer density and extensions. We also find that chitin, a major component of the inner layer of the yeast cell wall, is much more abundant in C. albicans. These differences in molecular properties, further supported by flow cytometry measurements, may play an important role in strengthening cell wall mechanics and immune interactions. This study demonstrates that single-molecule AFM, combined with immunological and fluorescence methods, is a powerful platform in fungal glycobiology for probing the density, distribution and extension of specific cell wall glycoconjugates. In nanomedicine, we anticipate that this new form of AFM-based nanoglycobiology will contribute to the development of sugar-based drugs, immunotherapeutics, vaccines and diagnostics.
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Affiliation(s)
- Sofiane El-Kirat-Chatel
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud, 1, bte L7.04.01., B-1348 Louvain-la-Neuve, Belgium
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360
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Abstract
Productive cell proliferation involves efficient and accurate splitting of the dividing cell into two separate entities. This orderly process reflects coordination of diverse cytological events by regulatory systems that drive the cell from mitosis into G1. In the budding yeast Saccharomyces cerevisiae, separation of mother and daughter cells involves coordinated actomyosin ring contraction and septum synthesis, followed by septum destruction. These events occur in precise and rapid sequence once chromosomes are segregated and are linked with spindle organization and mitotic progress by intricate cell cycle control machinery. Additionally, critical paarts of the mother/daughter separation process are asymmetric, reflecting a form of fate specification that occurs in every cell division. This chapter describes central events of budding yeast cell separation, as well as the control pathways that integrate them and link them with the cell cycle.
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361
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Kdx1 regulates RCK1 gene expression by interacting with Rlm1 in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2013; 435:350-5. [DOI: 10.1016/j.bbrc.2013.04.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/25/2013] [Indexed: 11/16/2022]
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362
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Bonnet C, Rigaud C, Chanteclaire E, Blandais C, Tassy-Freches E, Arico C, Javaud C. PCR on yeast colonies: an improved method for glyco-engineered Saccharomyces cerevisiae. BMC Res Notes 2013; 6:201. [PMID: 23688076 PMCID: PMC3664073 DOI: 10.1186/1756-0500-6-201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 05/08/2013] [Indexed: 01/13/2023] Open
Abstract
Background Saccharomyces cerevisiae is extensively used in bio-industries. However, its genetic engineering to introduce new metabolism pathways can cause unexpected phenotypic alterations. For example, humanisation of the glycosylation pathways is a high priority pharmaceutical industry goal for production of therapeutic glycoproteins in yeast. Genomic modifications can lead to several described physiological changes: biomass yields decrease, temperature sensitivity or cell wall structure modifications. We have observed that deletion of several N-mannosyltransferases in Saccharomyces cerevisiae, results in strains that can no longer be analyzed by classical PCR on yeast colonies. Findings In order to validate our glyco-engineered Saccharomyces cerevisiae strains, we developed a new protocol to carry out PCR directly on genetically modified yeast colonies. A liquid culture phase, combined with the use of a Hot Start DNA polymerase, allows a 3-fold improvement of PCR efficiency. The results obtained are repeatable and independent of the targeted sequence; as such the protocol is well adapted for intensive screening applications. Conclusions The developed protocol enables by-passing of many of the difficulties associated with PCR caused by phenotypic modifications brought about by humanisation of the glycosylation in yeast and allows rapid validation of glyco-engineered Saccharomyces cerevisiae cells. It has the potential to be extended to other yeast strains presenting cell wall structure modifications.
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363
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Yano K, Uesono Y, Yoshida S, Kikuchi A, Kashiwazaki J, Mabuchi I, Kikuchi Y. Mih1/Cdc25 is negatively regulated by Pkc1 inSaccharomyces cerevisiae. Genes Cells 2013; 18:425-41. [DOI: 10.1111/gtc.12047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/13/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Kouitiro Yano
- Department of Biological Sciences, Graduate School of Science; The University of Tokyo; 7-3-1 Hongo; Bunkyo-ku; Tokyo; 113-0033; Japan
| | - Yukifumi Uesono
- Department of Biological Sciences, Graduate School of Science; The University of Tokyo; 7-3-1 Hongo; Bunkyo-ku; Tokyo; 113-0033; Japan
| | - Satoshi Yoshida
- Department of Biology and Rosenstiel Basic Biomedical Sciences Research Center; Brandeis University; 415 South Street; Waltham; MA; 02454; USA
| | - Akihiko Kikuchi
- School of Medicine; Nagoya University; Tsurumai; Shouwa-ku; Nagoya; Aichi; 466-8550; Japan
| | - Jun Kashiwazaki
- Department of Life Science, Faculty of Science; Gakushuin University; 1-5-1 Mejiro; Toshima-ku; Tokyo; 171-8588; Japan
| | - Issei Mabuchi
- Department of Life Science, Faculty of Science; Gakushuin University; 1-5-1 Mejiro; Toshima-ku; Tokyo; 171-8588; Japan
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364
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Loibl M, Strahl S. Protein O-mannosylation: what we have learned from baker's yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2438-46. [PMID: 23434682 DOI: 10.1016/j.bbamcr.2013.02.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/05/2013] [Accepted: 02/10/2013] [Indexed: 01/06/2023]
Abstract
BACKGROUND Protein O-mannosylation is a vital type of glycosylation that is conserved among fungi, animals, and humans. It is initiated in the endoplasmic reticulum (ER) where the synthesis of the mannosyl donor substrate and the mannosyltransfer to proteins take place. O-mannosylation defects interfere with cell wall integrity and ER homeostasis in yeast, and define a pathomechanism of severe neuromuscular diseases in humans. SCOPE OF REVIEW On the molecular level, the O-mannosylation pathway and the function of O-mannosyl glycans have been characterized best in the eukaryotic model yeast Saccharomyces cerevisiae. In this review we summarize general features of protein O-mannosylation, including biosynthesis of the mannosyl donor, characteristics of acceptor substrates, and the protein O-mannosyltransferase machinery in the yeast ER. Further, we discuss the role of O-mannosyl glycans and address the question why protein O-mannosylation is essential for viability of yeast cells. GENERAL SIGNIFICANCE Understanding of the molecular mechanisms of protein O-mannosylation in yeast could lead to the development of novel antifungal drugs. In addition, transfer of the knowledge from yeast to mammals could help to develop diagnostic and therapeutic approaches in the frame of neuromuscular diseases. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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365
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Grice CM, Bertuzzi M, Bignell EM. Receptor-mediated signaling in Aspergillus fumigatus. Front Microbiol 2013; 4:26. [PMID: 23430083 PMCID: PMC3576715 DOI: 10.3389/fmicb.2013.00026] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 02/01/2013] [Indexed: 11/15/2022] Open
Abstract
Aspergillus fumigatus is the most pathogenic species among the Aspergilli, and the major fungal agent of human pulmonary infection. To prosper in diverse ecological niches, Aspergilli have evolved numerous mechanisms for adaptive gene regulation, some of which are also crucial for mammalian infection. Among the molecules which govern such responses, integral membrane receptors are thought to be the most amenable to therapeutic modulation. This is due to the localization of these molecular sensors at the periphery of the fungal cell, and to the prevalence of small molecules and licensed drugs which target receptor-mediated signaling in higher eukaryotic cells. In this review we highlight the progress made in characterizing receptor-mediated environmental adaptation in A. fumigatus and its relevance for pathogenicity in mammals. By presenting a first genomic survey of integral membrane proteins in this organism, we highlight an abundance of putative seven transmembrane domain (7TMD) receptors, the majority of which remain uncharacterized. Given the dependency of A. fumigatus upon stress adaptation for colonization and infection of mammalian hosts, and the merits of targeting receptor-mediated signaling as an antifungal strategy, a closer scrutiny of sensory perception and signal transduction in this organism is warranted.
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Affiliation(s)
- C M Grice
- South Kensington Campus, Imperial College London London, UK
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366
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Abstract
Understanding the pathogenesis of an infectious disease is critical for developing new methods to prevent infection and diagnose or cure disease. Adherence of microorganisms to host tissue is a prerequisite for tissue invasion and infection. Fungal cell wall adhesins involved in adherence to host tissue or abiotic medical devices are critical for colonization leading to invasion and damage of host tissue. Here, with a main focus on pathogenic Candida species, we summarize recent progress made in the field of adhesins in human fungal pathogens and underscore the importance of these proteins in establishment of fungal diseases.
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367
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El-Kirat-Chatel S, Beaussart A, Alsteens D, Jackson DN, Lipke PN, Dufrêne YF. Nanoscale analysis of caspofungin-induced cell surface remodelling in Candida albicans. NANOSCALE 2013; 5:1105-15. [PMID: 23262781 PMCID: PMC3564254 DOI: 10.1039/c2nr33215a] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The advent of fungal pathogens that are resistant to the classic repertoire of antifungal drugs has increased the need for new therapeutic agents. A prominent example of such a novel compound is caspofungin, known to alter cell wall biogenesis by inhibiting β-1,3-D-glucan synthesis. Although much progress has been made in understanding the mechanism of action of caspofungin, little is known about its influence on the biophysical properties of the fungal cells. Here, we use atomic force microscopy (AFM) to demonstrate that caspofungin induces major remodelling of the cell surface properties of Candida albicans. Caspofungin causes major morphological and structural alterations of the cells, which correlate with a decrease of the cell wall mechanical strength. Moreover, we find that the drug induces the massive exposure of the cell adhesion protein Als1 on the cell surface and leads to increased cell surface hydrophobicity, two features that trigger cell aggregation. This behaviour is not observed in yeast species lacking Als1, demonstrating the key role that the protein plays in determining the aggregation phenotype of C. albicans. The results show that AFM opens up new avenues for understanding the molecular bases of microbe-drug interactions and for developing new therapeutic agents.
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Affiliation(s)
- Sofiane El-Kirat-Chatel
- Université catholique de Louvain, Institute of Life Sciences & Institute of Condensed Matter and Nanosciences, Croix du Sud, 1, bte L7.04.01., B-1348 Louvain-la-Neuve, Belgium
| | - Audrey Beaussart
- Université catholique de Louvain, Institute of Life Sciences & Institute of Condensed Matter and Nanosciences, Croix du Sud, 1, bte L7.04.01., B-1348 Louvain-la-Neuve, Belgium
| | - David Alsteens
- Université catholique de Louvain, Institute of Life Sciences & Institute of Condensed Matter and Nanosciences, Croix du Sud, 1, bte L7.04.01., B-1348 Louvain-la-Neuve, Belgium
| | - Desmond N. Jackson
- Department of Biology, Brooklyn College of City University of New York, Brooklyn, New York 11210, USA
| | - Peter N. Lipke
- Department of Biology, Brooklyn College of City University of New York, Brooklyn, New York 11210, USA
| | - Yves F. Dufrêne
- Université catholique de Louvain, Institute of Life Sciences & Institute of Condensed Matter and Nanosciences, Croix du Sud, 1, bte L7.04.01., B-1348 Louvain-la-Neuve, Belgium
- Corresponding authors:
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368
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Raina SK, Wankhede DP, Sinha AK. Catharanthus roseus mitogen-activated protein kinase 3 confers UV and heat tolerance to Saccharomyces cerevisiae. PLANT SIGNALING & BEHAVIOR 2013; 8:e22716. [PMID: 23221751 PMCID: PMC3745576 DOI: 10.4161/psb.22716] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 10/30/2012] [Indexed: 06/01/2023]
Abstract
Catharanthus roseus is an important source of pharmaceutically important Monoterpenoid Indole Alkaloids (MIAs). Accumulation of many of the MIAs is induced in response to abiotic stresses such as wound, ultra violet (UV) irradiations, etc. Recently, we have demonstrated a possible role of CrMPK3, a C. roseus mitogen-activated protein kinase in stress-induced accumulation of a few MIAs. Here, we extend our findings using Saccharomyces cerevisiae to investigate the role of CrMPK3 in giving tolerance to abiotic stresses. Yeast cells transformed with CrMPK3 was found to show enhanced tolerance to UV and heat stress. Comparison of CrMPK3 and SLT2, a MAPK from yeast shows high-sequence identity particularly at conserved domains. Additionally, heat stress is also shown to activate a 43 kDa MAP kinase, possibly CrMPK3 in C. roseus leaves. These findings indicate the role of CrMPK3 in stress-induced MIA accumulation as well as in stress tolerance.
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369
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Tam J, Salgado S, Miltenburg M, Maheshwari V. Electrochemical synthesis on single cells as templates. Chem Commun (Camb) 2013; 49:8641-3. [DOI: 10.1039/c3cc44308f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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370
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Abstract
The composition and organization of the cell walls from Saccharomyces cerevisiae, Candida albicans, Aspergillus fumigatus, Schizosaccharomyces pombe, Neurospora crassa, and Cryptococcus neoformans are compared and contrasted. These cell walls contain chitin, chitosan, β-1,3-glucan, β-1,6-glucan, mixed β-1,3-/β-1,4-glucan, α-1,3-glucan, melanin, and glycoproteins as major constituents. A comparison of these cell walls shows that there is a great deal of variability in fungal cell wall composition and organization. However, in all cases, the cell wall components are cross-linked together to generate a cell wall matrix. The biosynthesis and properties of each of the major cell wall components are discussed. The chitin and glucans are synthesized and extruded into the cell wall space by plasma membrane-associated chitin synthases and glucan synthases. The glycoproteins are synthesized by ER-associated ribosomes and pass through the canonical secretory pathway. Over half of the major cell wall proteins are modified by the addition of a glycosylphosphatidylinositol anchor. The cell wall glycoproteins are also modified by the addition of O-linked oligosaccharides, and their N-linked oligosaccharides are extensively modified during their passage through the secretory pathway. These cell wall glycoprotein posttranslational modifications are essential for cross-linking the proteins into the cell wall matrix. Cross-linking the cell wall components together is essential for cell wall integrity. The activities of four groups of cross-linking enzymes are discussed. Cell wall proteins function as cross-linking enzymes, structural elements, adhesins, and environmental stress sensors and protect the cell from environmental changes.
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Affiliation(s)
- Stephen J Free
- Department of Biological Sciences, SUNY, University at Buffalo, Buffalo, New York, USA.
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371
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Patil PS, Lee CC, Huang YW, Zulueta MML, Hung SC. Regioselective and stereoselective benzylidene installation and one-pot protection of d-mannose. Org Biomol Chem 2013; 11:2605-12. [DOI: 10.1039/c3ob40079d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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372
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Munro CA. Chitin and glucan, the yin and yang of the fungal cell wall, implications for antifungal drug discovery and therapy. ADVANCES IN APPLIED MICROBIOLOGY 2013; 83:145-72. [PMID: 23651596 DOI: 10.1016/b978-0-12-407678-5.00004-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The structural carbohydrate polymers glucan and chitin compliment and reinforce each other in a dynamic process to maintain the integrity and physical strength of the fungal cell wall. The assembly of chitin and glucan in the cell wall of the budding yeast Saccharomyces cerevisiae and the polymorphic human pathogen Candida albicans are essential processes that involve a range of fungal-specific enzymes and regulatory networks. The fungal cell wall is, therefore, an attractive target for novel therapies as host cells lack many cell wall-related proteins. The most recent class of antifungal drug approved for clinical use, the echinocandins, targets the synthesis of cell wall β(1-3)glucan. The echinocandins are effective at treating invasive and bloodstream Candida infections and are now widely used in the clinic. However, there have been sporadic reports of breakthrough infections in patients undergoing echinocandin therapy. The acquisition of point mutations in the FKS genes that encode the catalytic β(1-3)glucan synthase subunits, the target of the echinocandins, has emerged as a dominant resistance mechanism. Cells with elevated chitin levels are also less susceptible to echinocandins and in addition, treatment with sub-MIC echinocandin activates cell wall salvage pathways that increase chitin synthesis to compensate for reduced glucan production. The development of drugs targeting the cell wall has already proven to be beneficial in providing an alternative class of drug for use in the clinic. Other cell wall targets such as chitin synthesis still hold great potential for drug development but careful consideration should be given to the capacity of fungi to manipulate their walls in a dynamic response to cell wall perturbations.
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Affiliation(s)
- Carol A Munro
- School of Medical Sciences, University of Aberdeen, Aberdeen, UK, E-mail:
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373
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Chaudhari R, Stenson J, Overton T, Thomas C. Effect of bud scars on the mechanical properties of Saccharomyces cerevisiae cell walls. Chem Eng Sci 2012. [DOI: 10.1016/j.ces.2012.08.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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374
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Muccilli S, Wemhoff S, Restuccia C, Meinhardt F. Exoglucanase-encoding genes from three Wickerhamomyces anomalus killer strains isolated from olive brine. Yeast 2012; 30:33-43. [PMID: 23148020 DOI: 10.1002/yea.2935] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 10/08/2012] [Indexed: 11/08/2022] Open
Abstract
Wickerhamomyces anomalus killer strains are important for fighting pathogenic yeasts and for controlling harmful yeasts and bacteria in the food industry. Targeted disruption of key genes in β-glucan synthesis of a sensitive Saccharomyces cerevisiae strain conferred resistance to the toxins of W. anomalus strains BS91, BCA15 and BCU24 isolated from olive brine. Competitive inhibition of the killing activities by laminarin and pustulan refer to β-1,3- and β-1,6-glucans as the main primary toxin targets. The extracellular exoglucanase-encoding genes WaEXG1 and WaEXG2 from the three strains were sequenced and were found to display noticeable similarities to those from known potent W. anomalus killer strains.
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Affiliation(s)
- Serena Muccilli
- DISPA, Sezione di Tecnologia e Microbiologia degli Alimenti, University of Catania, Italy
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375
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Orlean P. Architecture and biosynthesis of the Saccharomyces cerevisiae cell wall. Genetics 2012; 192:775-818. [PMID: 23135325 PMCID: PMC3522159 DOI: 10.1534/genetics.112.144485] [Citation(s) in RCA: 303] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/06/2012] [Indexed: 01/02/2023] Open
Abstract
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.
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Affiliation(s)
- Peter Orlean
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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376
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β-1,3-Glucan, Which Can Be Targeted by Drugs, Forms a Trabecular Scaffold in the Oocyst Walls of
Toxoplasma
and
Eimeria. mBio 2012; 3:mBio.00258-12. [PMID: 23015739 PMCID: PMC3518913 DOI: 10.1128/mbio.00258-12] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The walls of infectious pathogens, which are essential for transmission, pathogenesis, and diagnosis, contain sugar polymers that are defining structural features, e.g., β-1,3-glucan and chitin in fungi, chitin in Entamoeba cysts, β-1,3-GalNAc in Giardia cysts, and peptidoglycans in bacteria. The goal here was to determine in which of three walled forms of Toxoplasma gondii (oocyst, sporocyst, or tissue cyst) is β-1,3-glucan, the product of glucan synthases and glucan hydrolases predicted by whole-genome sequences of the parasite. The three most important discoveries were as follows. (i) β-1,3-glucan is present in oocyst walls of Toxoplasma and Eimeria (a chicken parasite that is a model for intestinal stages of Toxoplasma) but is absent from sporocyst and tissue cyst walls. (ii) Fibrils of β-1,3-glucan are part of a trabecular scaffold in the inner layer of the oocyst wall, which also includes a glucan hydrolase that has a novel glucan-binding domain. (iii) Echinocandins, which target the glucan synthase and kill fungi, arrest development of the Eimeria oocyst wall and prevent release of the parasites into the intestinal lumen. In summary, β-1,3-glucan, which can be targeted by drugs, is an important component of oocyst walls of Toxoplasma but is not a component of sporocyst and tissue cyst walls. We show here that walls of Toxoplasma oocysts, the infectious stage shed by cats, contain β-1,3-glucan, a sugar polymer that is a major component of fungal walls. In contrast to fungi, β-1,3-glucan is part of a trabecular scaffold in the inner layer of the oocyst wall that is independent of the permeability barrier formed by the outer layer of the wall. While glucan synthase inhibitors kill fungi, these inhibitors arrest the development of the oocyst walls of Eimeria (an important chicken pathogen that is a surrogate for Toxoplasma) and block release of oocysts into the intestinal lumen. The absence of β-1,3-glucan in tissue cysts of Toxoplasma suggests that drugs targeted at the glucan synthase might be used to treat Eimeria in chickens but not to treat Toxoplasma in people.
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377
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Blasco L, Veiga-Crespo P, Sánchez-Pérez A, Villa TG. Cloning and characterization of the beer foaming gene CFG1 from Saccharomyces pastorianus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:10796-10807. [PMID: 23039128 DOI: 10.1021/jf3027974] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Foam production is an essential characteristic of beer, generated mainly from the proteins present in the malt and, to a minor extent, from the mannoproteins in brewer's yeast cell walls. Here, we describe the isolation and characterization of the novel fermentation gene CFG1 (Carlsbergensis foaming gene) from Saccharomyces pastorianus. CFG1 encodes the cell wall protein Cfg1p, a 105 kDa protein highly homologous to Saccharomyces cerevisiae cell wall mannoproteins, particularly those involved in foam formation, such as Awa1p and Fpg1p. Further characterization of Cfg1p revealed that this novel protein is responsible for beer foam stabilization. This report represents the first time that a brewing yeast foaming gene has been cloned and its action fully characterized.
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Affiliation(s)
- Lucía Blasco
- Department of Microbiology, School of Biotechnology, Faculty of Pharmacy, University of Santiago de Compostela, 15782, Spain
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378
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Lin X, Yang F, Zhou Y, Zhu Z, Jin G, Zhang S, Zhao ZK. Highly-efficient colony PCR method for red yeasts and its application to identify mutations within two leucine auxotroph mutants. Yeast 2012; 29:467-74. [PMID: 23065821 DOI: 10.1002/yea.2926] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 08/21/2012] [Accepted: 08/30/2012] [Indexed: 11/05/2022] Open
Abstract
Red yeasts hold great promise in the production of microbial lipids and carotenoids. Genetic study of red yeasts has attracted much attention; however, rapid amplification of genes from red yeast samples remains technically challenging. Here a highly efficient method for the preparation of genomic DNA (gDNA) template, which could be directly used for PCR, was developed. Cells from colonies or liquid cultures were collected and sequentially treated by microwave, plMAN5C, proteinase K and boiling (MMPB) in a single tube to give cell lysates that were qualified as PCR templates. Single-copied gDNA fragments o up to 2.8 kb were successfully amplified. We also demonstrated successful application of this method for species in the Ascomycetes and Basidiomycetes and identification of two leucine auxotroph mutants of Rhodotorula glutinis. This method could be widely employed for the screening and genetic engineering of various yeasts.
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Affiliation(s)
- Xinping Lin
- Dalian Institute of Chemical Physics, CAS, People's Republic of China
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379
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Abstract
The cell wall integrity (CWI) signal transduction pathway, which has been well-studied in the yeast Saccharomyces cerevisiae, plays an important role in the regulation of cell wall biogenesis. Recently, we characterized the CWI stress sensor orthologs WscA and WscB in the filamentous fungus Aspergillus nidulans. Disruption of the wscA and wscB genes causes a change in the transcriptional levels of agsA and agsB, which encode α-1,3-glucan synthase, resulting in an increase in alkaline soluble cell wall glucan. However, the contribution of these putative sensors to downstream CWI pathway signaling remains unclear because MpkA-RlmA signaling remains active in wscA-wscB double disruptants exposed to cell wall stress associated with exposure to micafungin, a potent inhibitor of β-1,3-glucan synthase. In this addendum, we report the results of further studies involving hypo-osmotic shock as a stressor that suggest WscA and WscB are not essential for MpkA-RlmA signaling. Finally, we describe for the first time other Aspergillus CWI stress sensor candidate Mid2-like protein.
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Affiliation(s)
- Taiki Futagami
- Department of Bioscience and Biotechnology; Faculty of Agriculture; Kyushu University; Hakozaki, Japan
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380
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Aguilar B, Solís J, Viveros JM, López Z, Knauth P. Characterization of Cell Wall Extracts fromSaccharomyces cerevisiaewith Immunological Activity. FOOD BIOTECHNOL 2012. [DOI: 10.1080/08905436.2012.723604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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381
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Guan B, Lei J, Su S, Chen F, Duan Z, Chen Y, Gong X, Li H, Jin J. Absence of Yps7p, a putative glycosylphosphatidylinositol-linked aspartyl protease in Pichia pastoris, results in aberrant cell wall composition and increased osmotic stress resistance. FEMS Yeast Res 2012; 12:969-79. [PMID: 22943416 DOI: 10.1111/1567-1364.12002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/12/2012] [Accepted: 08/24/2012] [Indexed: 11/27/2022] Open
Abstract
Recently, studies performed on Saccharomyces cerevisiae and Candida albicans have confirmed the importance of fungal glycosylphosphatidylinositol (GPI)-anchored aspartyl proteases (yapsins) for cell-wall integrity. Genome sequence annotation of Pichia pastoris also revealed seven putative GPI-anchored aspartyl protease genes. The five yapsin genes assigned as YPS1, YPS2, YPS3, YPS7 and MKC7 in P. pastoris were disrupted. Among these putative GPI-linked aspartyl proteases, disruption of PpYPS7 gene confers the Ppyps7Δ mutant cell increased resistance to cell wall perturbing reagents congo red, calcofluor white (CW) and sodium dodecyl sulfate. Quantitative analysis of cell wall components shows lower content of chitin and increased amounts of β-1,3-glucan. Further staining of the cell with CW demonstrates that disruption of PpYPS7 gene causes a reduction of the chitin content in lateral cell wall. Consistently, transmission electron micrographs show that the inner layer of mutant cell wall, mainly composed of chitin and β-1, 3-glucan, is much thicker than that in parental strain GS115. Additionally, Ppyps7Δ mutant also exhibits increased osmotic resistance compared with parental strain GS115. This could be due to the dramatically elevated intracellular glycerol level in Ppyps7Δ mutant. These results suggest that PpYPS7 is involved in cell wall integrity and response to osmotic stress.
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Affiliation(s)
- Bo Guan
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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382
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Yu Q, Wang H, Xu N, Cheng X, Wang Y, Zhang B, Xing L, Li M. Spf1 strongly influences calcium homeostasis, hyphal development, biofilm formation and virulence in Candida albicans. Microbiology (Reading) 2012; 158:2272-2282. [DOI: 10.1099/mic.0.057232-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, Nankai University, Tianjin, PR China
| | - Hui Wang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, Nankai University, Tianjin, PR China
| | - Ning Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, Nankai University, Tianjin, PR China
| | - Xinxin Cheng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, Nankai University, Tianjin, PR China
| | - Yuzhou Wang
- Experimental Animal Center, College of Life Science, Nankai University, Tianjin, PR China
| | - Biao Zhang
- Tianjin Traditional Chinese Medicine University, Tianjin, PR China
| | - Laijun Xing
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, Nankai University, Tianjin, PR China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, Nankai University, Tianjin, PR China
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383
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Functional analysis of glycoside hydrolase family 18 and 20 genes in Neurospora crassa. Fungal Genet Biol 2012; 49:717-30. [DOI: 10.1016/j.fgb.2012.06.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 12/14/2022]
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384
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Maddi A, Dettman A, Fu C, Seiler S, Free SJ. WSC-1 and HAM-7 are MAK-1 MAP kinase pathway sensors required for cell wall integrity and hyphal fusion in Neurospora crassa. PLoS One 2012; 7:e42374. [PMID: 22879952 PMCID: PMC3411791 DOI: 10.1371/journal.pone.0042374] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/04/2012] [Indexed: 11/18/2022] Open
Abstract
A large number of cell wall proteins are encoded in the Neurospora crassa genome. Strains carrying gene deletions of 65 predicted cell wall proteins were characterized. Deletion mutations in two of these genes (wsc-1 and ham-7) have easily identified morphological and inhibitor-based defects. Their phenotypic characterization indicates that HAM-7 and WSC-1 function during cell-to-cell hyphal fusion and in cell wall integrity maintenance, respectively. wsc-1 encodes a transmembrane protein with extensive homology to the yeast Wsc family of sensor proteins. In N. crassa, WSC-1 (and its homolog WSC-2) activates the cell wall integrity MAK-1 MAP kinase pathway. The GPI-anchored cell wall protein HAM-7 is required for cell-to-cell fusion and the sexual stages of the N. crassa life cycle. Like WSC-1, HAM-7 is required for activating MAK-1. A Δwsc-1;Δham-7 double mutant fully phenocopies mutants lacking components of the MAK-1 MAP kinase cascade. The data identify WSC-1 and HAM-7 as the major cell wall sensors that regulate two distinct MAK-1-dependent cellular activities, cell wall integrity and hyphal anastomosis, respectively.
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Affiliation(s)
- Abhiram Maddi
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
- Department of Periodontics and Endodontics, School of Dental Medicine, State University of New York, University at Buffalo, Buffalo, New York, United States of America
| | - Anne Dettman
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August-University, Göttingen, Germany
| | - Ci Fu
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
| | - Stephan Seiler
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August-University, Göttingen, Germany
- * E-mail: (SS); (SF)
| | - Stephen J. Free
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
- * E-mail: (SS); (SF)
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385
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Austriaco N. Endoplasmic reticulum involvement in yeast cell death. Front Oncol 2012; 2:87. [PMID: 22876361 PMCID: PMC3410633 DOI: 10.3389/fonc.2012.00087] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 07/17/2012] [Indexed: 11/21/2022] Open
Abstract
Yeast cells undergo programed cell death (PCD) with characteristic markers associated with apoptosis in mammalian cells including chromatin breakage, nuclear fragmentation, reactive oxygen species generation, and metacaspase activation. Though significant research has focused on mitochondrial involvement in this phenomenon, more recent work with both Saccharomyces cerevisiae and Schizosaccharomyces pombe has also implicated the endoplasmic reticulum (ER) in yeast PCD. This minireview provides an overview of ER stress-associated cell death (ER-SAD) in yeast. It begins with a description of ER structure and function in yeast before moving to a discussion of ER-SAD in both mammalian and yeast cells. Three examples of yeast cell death associated with the ER will be highlighted here including inositol starvation, lipid toxicity, and the inhibition of N-glycosylation. It closes by suggesting ways to further examine the involvement of the ER in yeast cell death.
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386
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Taff HT, Nett JE, Zarnowski R, Ross KM, Sanchez H, Cain MT, Hamaker J, Mitchell AP, Andes DR. A Candida biofilm-induced pathway for matrix glucan delivery: implications for drug resistance. PLoS Pathog 2012; 8:e1002848. [PMID: 22876186 PMCID: PMC3410897 DOI: 10.1371/journal.ppat.1002848] [Citation(s) in RCA: 211] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 06/22/2012] [Indexed: 01/10/2023] Open
Abstract
Extracellular polysaccharides are key constituents of the biofilm matrix of many microorganisms. One critical carbohydrate component of Candida albicans biofilms, β-1,3 glucan, has been linked to biofilm protection from antifungal agents. In this study, we identify three glucan modification enzymes that function to deliver glucan from the cell to the extracellular matrix. These enzymes include two predicted glucan transferases and an exo-glucanase, encoded by BGL2, PHR1, and XOG1, respectively. We show that the enzymes are crucial for both delivery of β-1,3 glucan to the biofilm matrix and for accumulation of mature matrix biomass. The enzymes do not appear to impact cell wall glucan content of biofilm cells, nor are they necessary for filamentation or biofilm formation. We demonstrate that mutants lacking these genes exhibit enhanced susceptibility to the commonly used antifungal, fluconazole, during biofilm growth only. Transcriptional analysis and biofilm phenotypes of strains with multiple mutations suggest that these enzymes act in a complementary fashion to distribute matrix downstream of the primary β-1,3 glucan synthase encoded by FKS1. Furthermore, our observations suggest that this matrix delivery pathway works independently from the C. albicans ZAP1 matrix formation regulatory pathway. These glucan modification enzymes appear to play a biofilm-specific role in mediating the delivery and organization of mature biofilm matrix. We propose that the discovery of inhibitors for these enzymes would provide promising anti-biofilm therapeutics.
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Affiliation(s)
- Heather T. Taff
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Jeniel E. Nett
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Robert Zarnowski
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Kelly M. Ross
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Hiram Sanchez
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Mike T. Cain
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
| | - Jessica Hamaker
- Department of Microbiology, Columbia University, New York, New York
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - David R. Andes
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin
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387
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Lasiodiplodan, an exocellular (1→6)-β-d-glucan from Lasiodiplodia theobromae MMPI: production on glucose, fermentation kinetics, rheology and anti-proliferative activity. ACTA ACUST UNITED AC 2012; 39:1179-88. [DOI: 10.1007/s10295-012-1112-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/17/2012] [Indexed: 10/28/2022]
Abstract
Abstract
Lasiodiplodan, an exopolysaccharide of the (1→6)-β-d-glucan type, is produced by Lasiodiplodia theobromae MMPI when grown under submerged culture on glucose. The objective of this study was to evaluate lasiodiplodan production by examining the effects of carbon (glucose, fructose, maltose, sucrose) and nitrogen sources (KNO3, (NH4)2SO4, urea, yeast extract, peptone), its production in shake flasks compared to a stirred-tank bioreactor, and to study the rheology of lasiodiplodan, and lasiodiplodan’s anti-proliferative effect on breast cancer MCF-7 cells. Although glucose (2.05 ± 0.05 g L−1), maltose (2.08 ± 0.04 g L−1) and yeast extract (2.46 ± 0.06 g L−1) produced the highest amounts of lasiodiplodan, urea as N source resulted in more lasiodiplodan per unit biomass than yeast extract (0.74 ± 0.006 vs. 0.22 ± 0.008 g g−1). A comparison of the fermentative parameters of L. theobromae MMPI in shake flasks and a stirred-tank bioreactor at 120 h on glucose as carbon source showed maximum lasiodiplodan production in agitated flasks (7.01 ± 0.07 g L−1) with a specific yield of 0.25 ± 0.57 g g−1 and a volumetric productivity of 0.06 ± 0.001 g L−1 h−1. A factorial 22 statistical design developed to evaluate the effect of glucose concentration (20–60 g L−1) and impeller speed (100–200 rpm) on lasiodiplodan production in the bioreactor showed the highest production (6.32 g L−1) at 72 h. Lasiodiplodan presented pseudoplastic behaviour, and the apparent viscosity increased at 60°C in the presence of CaCl2. Anti-proliferative activity of lasiodiplodan was demonstrated in MCF-7 cells, which was time- and dose-dependent with an IC50 of 100 μg lasiodiplodan mL−1.
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388
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Wloka C, Bi E. Mechanisms of cytokinesis in budding yeast. Cytoskeleton (Hoboken) 2012; 69:710-26. [DOI: 10.1002/cm.21046] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 06/15/2012] [Indexed: 01/22/2023]
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389
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Maddi A, Fu C, Free SJ. The Neurospora crassa dfg5 and dcw1 genes encode α-1,6-mannanases that function in the incorporation of glycoproteins into the cell wall. PLoS One 2012; 7:e38872. [PMID: 22701726 PMCID: PMC3372484 DOI: 10.1371/journal.pone.0038872] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/15/2012] [Indexed: 12/03/2022] Open
Abstract
The covalent cross-linking of cell wall proteins into the cell wall glucan/chitin matrix is an important step in the biogenesis of the fungal cell wall. We demonstrate that the Neurospora crassa DFG5 (NCU03770) and DCW1 (NCU08127) enzymes function in vivo to cross-link glycoproteins into the cell wall. Mutants lacking DFG5 or DCW1 release slightly elevated levels of cell wall proteins into their growth medium. Mutants lacking both DFG5 and DCW1 have substantially reduced levels of cell wall proteins in their cell walls and release large amounts of known cell wall proteins into the medium. DFG5 and DCW1 are members of the GH76 family of glycosyl hydrolases, which have specificity to recognize and cleave α-1,6-mannans. A model for incorporation of glycoproteins into the cell wall through the α-1,6-mannan core of the N-linked galactomannan is presented. In this model, DFG5 and DCW1 recognize the N-linked galactomannan present on glycoproteins and cross-link it into the cell wall glucan/chitin matrix.
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Affiliation(s)
- Abhiram Maddi
- Department of Periodontics and Endodontics, School of Dental Medicine, State University of New York, University at Buffalo, Buffalo, New York, United States of America
| | - Ci Fu
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
| | - Stephen J. Free
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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390
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Rapid redistribution of phosphatidylinositol-(4,5)-bisphosphate and septins during the Candida albicans response to caspofungin. Antimicrob Agents Chemother 2012; 56:4614-24. [PMID: 22687514 DOI: 10.1128/aac.00112-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We previously showed that phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] and septin regulation play major roles in maintaining Candida albicans cell wall integrity in response to caspofungin and other stressors. Here, we establish a link between PI(4,5)P2 signaling and septin localization and demonstrate that rapid redistribution of PI(4,5)P2 and septins is part of the natural response of C. albicans to caspofungin. First, we studied caspofungin-hypersusceptible C. albicans irs4 and inp51 mutants, which have elevated PI(4,5)P2 levels due to loss of PI(4,5)P2-specific 5'-phosphatase activity. PI(4,5)P2 accumulated in discrete patches, rather than uniformly, along surfaces of mutants in yeast and filamentous morphologies, as visualized with a green fluorescent protein (GFP)-pleckstrin homology domain. The patches also contained chitin (calcofluor white staining) and cell wall protein Rbt5 (Rbt5-GFP). By transmission electron microscopy, patches corresponded to plasma membrane invaginations that incorporated cell wall material. Fluorescently tagged septins Cdc10 and Sep7 colocalized to these sites, consistent with well-described PI(4,5)P2-septin physical interactions. Based on expression patterns of cell wall damage response genes, irs4 and inp51 mutants were firmly positioned within a group of caspofungin-hypersusceptible, septin-regulatory protein kinase mutants. irs4 and inp51 were linked most closely to the gin4 mutant by expression profiling, PI(4,5)P2-septin-chitin redistribution and other phenotypes. Finally, sublethal 5-min exposure of wild-type C. albicans to caspofungin resulted in redistribution of PI(4,5)P2 and septins in a manner similar to those of irs4, inp51, and gin4 mutants. Taken together, our data suggest that the C. albicans Irs4-Inp51 5'-phosphatase complex and Gin4 function upstream of PI(4,5)P2 and septins in a pathway that helps govern responses to caspofungin.
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391
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Bi E, Park HO. Cell polarization and cytokinesis in budding yeast. Genetics 2012; 191:347-87. [PMID: 22701052 PMCID: PMC3374305 DOI: 10.1534/genetics.111.132886] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Accepted: 11/04/2011] [Indexed: 12/26/2022] Open
Abstract
Asymmetric cell division, which includes cell polarization and cytokinesis, is essential for generating cell diversity during development. The budding yeast Saccharomyces cerevisiae reproduces by asymmetric cell division, and has thus served as an attractive model for unraveling the general principles of eukaryotic cell polarization and cytokinesis. Polarity development requires G-protein signaling, cytoskeletal polarization, and exocytosis, whereas cytokinesis requires concerted actions of a contractile actomyosin ring and targeted membrane deposition. In this chapter, we discuss the mechanics and spatial control of polarity development and cytokinesis, emphasizing the key concepts, mechanisms, and emerging questions in the field.
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Affiliation(s)
- Erfei Bi
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6058, USA.
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392
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Sanz AB, García R, Rodríguez-Peña JM, Díez-Muñiz S, Nombela C, Peterson CL, Arroyo J. Chromatin remodeling by the SWI/SNF complex is essential for transcription mediated by the yeast cell wall integrity MAPK pathway. Mol Biol Cell 2012; 23:2805-17. [PMID: 22621902 PMCID: PMC3395667 DOI: 10.1091/mbc.e12-04-0278] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In Saccharomyces cerevisiae, the transcriptional program triggered by cell wall stress is coordinated by Slt2/Mpk1, the mitogen-activated protein kinase (MAPK) of the cell wall integrity (CWI) pathway, and is mostly mediated by the transcription factor Rlm1. Here we show that the SWI/SNF chromatin-remodeling complex plays a critical role in orchestrating the transcriptional response regulated by Rlm1. swi/snf mutants show drastically reduced expression of cell wall stress-responsive genes and hypersensitivity to cell wall-interfering compounds. On stress, binding of RNA Pol II to the promoters of these genes depends on Rlm1, Slt2, and SWI/SNF. Rlm1 physically interacts with SWI/SNF to direct its association to target promoters. Finally, we observe nucleosome displacement at the CWI-responsive gene MLP1/KDX1, which relies on the SWI/SNF complex. Taken together, our results identify the SWI/SNF complex as a key element of the CWI MAPK pathway that mediates the chromatin remodeling necessary for adequate transcriptional response to cell wall stress.
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Affiliation(s)
- A Belén Sanz
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
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393
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Kwiatkowski S, Thielen U, Glenney P, Moran C. A Study of Saccharomyces cerevisiae Cell Wall Glucans. JOURNAL OF THE INSTITUTE OF BREWING 2012. [DOI: 10.1002/j.2050-0416.2009.tb00361.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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394
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Topological and mutational analysis of Saccharomyces cerevisiae Fks1. EUKARYOTIC CELL 2012; 11:952-60. [PMID: 22581527 DOI: 10.1128/ec.00082-12] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fks1, with orthologs in nearly all fungi as well as plants and many protists, plays a central role in fungal cell wall formation as the putative catalytic component of β-1,3-glucan synthase. It is also the target for an important new antifungal group, the echinocandins, as evidenced by the localization of resistance-conferring mutations to Fks1 hot spots 1, 2, and 3 (residues 635 to 649, 1354 to 1361, and 690 to 700, respectively). Since Fks1 is an integral membrane protein and echinocandins are cyclic peptides with lipid tails, Fks1 topology is key to understanding its function and interaction with echinocandins. We used hemagglutinin (HA)-Suc2-His4C fusions to C-terminally truncated Saccharomyces cerevisiae Fks1 to experimentally define its topology and site-directed mutagenesis to test function of selected residues. Of the 15 to 18 transmembrane helices predicted in silico for Fks1 from evolutionarily diverse fungi, 13 were experimentally confirmed. The N terminus (residues 1 to 445) is cytosolic and the C terminus (residues 1823 to 1876) external; both are essential to Fks1 function. The cytosolic central domain (residues 715 to 1294) includes newly recognized homology to glycosyltransferases, and residues potentially involved in substrate UDP-glucose binding and catalysis are essential. All three hot spots are external, with hot spot 1 adjacent to and hot spot 3 largely embedded within the outer leaflet of the membrane. This topology suggests a model in which echinocandins interact through their lipid tails with hot spot 3 and through their cyclic peptides with hot spots 1 and 2.
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395
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Disruption of the Eng18B ENGase gene in the fungal biocontrol agent Trichoderma atroviride affects growth, conidiation and antagonistic ability. PLoS One 2012; 7:e36152. [PMID: 22586463 PMCID: PMC3346758 DOI: 10.1371/journal.pone.0036152] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 03/27/2012] [Indexed: 02/07/2023] Open
Abstract
The recently identified phylogenetic subgroup B5 of fungal glycoside hydrolase family 18 genes encodes enzymes with mannosyl glycoprotein endo-N-acetyl-β-D-glucosaminidase (ENGase)-type activity. Intracellular ENGase activity is associated with the endoplasmic reticulum associated protein degradation pathway (ERAD) of misfolded glycoproteins, although the biological relevance in filamentous fungi is not known. Trichoderma atroviride is a mycoparasitic fungus that is used for biological control of plant pathogenic fungi. The present work is a functional study of the T. atroviride B5-group gene Eng18B, with emphasis on its role in fungal growth and antagonism. A homology model of T. atroviride Eng18B structure predicts a typical glycoside hydrolase family 18 (αβ)8 barrel architecture. Gene expression analysis shows that Eng18B is induced in dual cultures with the fungal plant pathogens Botrytis cinerea and Rhizoctonia solani, although a basal expression is observed in all growth conditions tested. Eng18B disruption strains had significantly reduced growth rates but higher conidiation rates compared to the wild-type strain. However, growth rates on abiotic stress media were significantly higher in Eng18B disruption strains compared to the wild-type strain. No difference in spore germination, germ-tube morphology or in hyphal branching was detected. Disruption strains produced less biomass in liquid cultures than the wild-type strain when grown with chitin as the sole carbon source. In addition, we determined that Eng18B is required for the antagonistic ability of T. atroviride against the grey mould fungus B. cinerea in dual cultures and that this reduction in antagonistic ability is partly connected to a secreted factor. The phenotypes were recovered by re-introduction of an intact Eng18B gene fragment in mutant strains. A putative role of Eng18B ENGase activity in the endoplasmic reticulum associated protein degradation pathway of endogenous glycoproteins in T. atroviride is discussed in relation to the observed phenotypes.
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396
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Regulation of cell wall biogenesis in Saccharomyces cerevisiae: the cell wall integrity signaling pathway. Genetics 2012; 189:1145-75. [PMID: 22174182 DOI: 10.1534/genetics.111.128264] [Citation(s) in RCA: 617] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
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.
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397
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Genome-wide analysis of cell wall-related genes in Tuber melanosporum. Curr Genet 2012; 58:165-77. [PMID: 22481122 DOI: 10.1007/s00294-012-0374-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/15/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
Abstract
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.
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398
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Piotrowski JS, Nagarajan S, Kroll E, Stanbery A, Chiotti KE, Kruckeberg AL, Dunn B, Sherlock G, Rosenzweig F. Different selective pressures lead to different genomic outcomes as newly-formed hybrid yeasts evolve. BMC Evol Biol 2012; 12:46. [PMID: 22471618 PMCID: PMC3372441 DOI: 10.1186/1471-2148-12-46] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Accepted: 04/02/2012] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Interspecific hybridization occurs in every eukaryotic kingdom. While hybrid progeny are frequently at a selective disadvantage, in some instances their increased genome size and complexity may result in greater stress resistance than their ancestors, which can be adaptively advantageous at the edges of their ancestors' ranges. While this phenomenon has been repeatedly documented in the field, the response of hybrid populations to long-term selection has not often been explored in the lab. To fill this knowledge gap we crossed the two most distantly related members of the Saccharomyces sensu stricto group, S. cerevisiae and S. uvarum, and established a mixed population of homoploid and aneuploid hybrids to study how different types of selection impact hybrid genome structure. RESULTS As temperature was raised incrementally from 31°C to 46.5°C over 500 generations of continuous culture, selection favored loss of the S. uvarum genome, although the kinetics of genome loss differed among independent replicates. Temperature-selected isolates exhibited greater inherent and induced thermal tolerance than parental species and founding hybrids, and also exhibited ethanol resistance. In contrast, as exogenous ethanol was increased from 0% to 14% over 500 generations of continuous culture, selection favored euploid S. cerevisiae x S. uvarum hybrids. Ethanol-selected isolates were more ethanol tolerant than S. uvarum and one of the founding hybrids, but did not exhibit resistance to temperature stress. Relative to parental and founding hybrids, temperature-selected strains showed heritable differences in cell wall structure in the forms of increased resistance to zymolyase digestion and Micafungin, which targets cell wall biosynthesis. CONCLUSIONS This is the first study to show experimentally that the genomic fate of newly-formed interspecific hybrids depends on the type of selection they encounter during the course of evolution, underscoring the importance of the ecological theatre in determining the outcome of the evolutionary play.
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Affiliation(s)
- Jeff S Piotrowski
- Chemical Genomics Research Group, RIKEN Advance Science Institute, Wako, Wako, Japan
- Division of Biological Sciences, The University of Montana, Missoula MT 59812, USA
| | - Saisubramanian Nagarajan
- School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram Thanjavur- 613401, Tamil Nadu, India
- Division of Biological Sciences, The University of Montana, Missoula MT 59812, USA
| | - Evgueny Kroll
- Division of Biological Sciences, The University of Montana, Missoula MT 59812, USA
| | - Alison Stanbery
- Division of Biological Sciences, The University of Montana, Missoula MT 59812, USA
| | - Kami E Chiotti
- Division of Biological Sciences, The University of Montana, Missoula MT 59812, USA
| | | | - Barbara Dunn
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Gavin Sherlock
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Frank Rosenzweig
- Division of Biological Sciences, The University of Montana, Missoula MT 59812, USA
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399
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Pga13 in Candida albicans is localized in the cell wall and influences cell surface properties, morphogenesis and virulence. Fungal Genet Biol 2012; 49:322-31. [DOI: 10.1016/j.fgb.2012.01.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/20/2012] [Accepted: 01/31/2012] [Indexed: 01/09/2023]
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400
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Kurita T, Noda Y, Yoda K. Action of multiple endoplasmic reticulum chaperon-like proteins is required for proper folding and polarized localization of Kre6 protein essential in yeast cell wall β-1,6-glucan synthesis. J Biol Chem 2012; 287:17415-17424. [PMID: 22447934 DOI: 10.1074/jbc.m111.321018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Saccharomyces cerevisiae Kre6 is a type II membrane protein essential for cell wall β-1,6-glucan synthesis. Recently we reported that the majority of Kre6 is in the endoplasmic reticulum (ER), but a significant portion of Kre6 is found in the plasma membrane of buds, and this polarized appearance of Kre6 is required for β-1,6-glucan synthesis. An essential membrane protein, Keg1, and ER chaperon Rot1 bind to Kre6. In this study we found that in mutant keg1-1 cells, accumulation of Kre6 at the buds is diminished, binding of Kre6 to Keg1 is decreased, and Kre6 becomes susceptible to ER-associated degradation (ERAD), which suggests Keg1 participates in folding and transport of Kre6. All mutants of the calnexin cycle member homologues (cwh41, rot2, kre5, and cne1) showed defects in β-1,6-glucan synthesis, although the calnexin chaperon system is considered not functional in yeast. We found synthetic defects between them and keg1-1, and Cne1 co-immunoprecipitated with Keg1 and Kre6. A stronger binding of Cne1 to Kre6 was detected when two glucosidases (Cwh41 and Rot2) that remove glucose on N-glycan were functional. Skn1, a Kre6 homologue, was not detected by immunofluorescence in the wild type yeast, but in kre6Δ cells it became detectable and behaved like Kre6. In conclusion, the action of multiple ER chaperon-like proteins is required for proper folding and localization of Kre6 and probably Skn1 to function in β-1,6-glucan synthesis.
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Affiliation(s)
- Tomokazu Kurita
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Yoichi Noda
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Koji Yoda
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan.
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