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Lok B, Adam MAA, Kamal LZM, Chukwudi NA, Sandai R, Sandai D. The assimilation of different carbon sources in Candida albicans: Fitness and pathogenicity. Med Mycol 2021; 59:115-125. [PMID: 32944760 DOI: 10.1093/mmy/myaa080] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/07/2020] [Accepted: 08/14/2020] [Indexed: 01/31/2023] Open
Abstract
Candida albicans is a commensal yeast commonly found on the skin and in the body. However, in immunocompromised individuals, the fungi could cause local and systemic infections. The carbon source available plays an important role in the establishment of C. albicans infections. The fungi's ability to assimilate a variety of carbon sources plays a vital role in its colonization, and by extension, its fitness and pathogenicity, as it often inhabits niches that are glucose-limited but rich in alternative carbon sources. A difference in carbon sources affect the growth and mating of C. albicans, which contributes to its pathogenicity as proliferation helps the fungi colonize its environment. The carbon source also affects its metabolism and signaling pathways, which are integral parts of the fungi's fitness and pathogenicity. As a big percentage of the carbon assimilated by C. albicans goes to cell wall biogenesis, the availability of different carbon sources will result in cell walls with variations in rigidity, adhesion, and surface hydrophobicity. In addition to the biofilm formation of the fungi, the carbon source also influences whether the fungi grow in yeast- or mycelial-form. Both forms play different roles in C. albicans's infection process. A better understanding of the role of the carbon sources in C. albicans's pathogenicity would contribute to more effective treatment solutions for fungal infections.
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Affiliation(s)
- Bronwyn Lok
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Mowaffaq Adam Ahmad Adam
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Laina Zarisa Mohd Kamal
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Nwakpa Anthony Chukwudi
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Rosline Sandai
- Faculty of Languages and Communication, Universiti Pendidikan Sultan Idris, Perak Darul Ridzuan, Malaysia
| | - Doblin Sandai
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
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Xian L, Feng JX. Purification and biochemical characterization of a novel mesophilic glucoamylase from Aspergillus tritici WZ99. Int J Biol Macromol 2017; 107:1122-1130. [PMID: 28951303 DOI: 10.1016/j.ijbiomac.2017.09.095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/20/2017] [Accepted: 09/22/2017] [Indexed: 11/17/2022]
Abstract
Glucoamylase, cleaving the nonreducing end of starch releasing glucose, is an important enzyme in starch processing. The optimal temperature for industrial glucoamylase activity is 60-70°C, which is not compatible with the optimal growth temperature for Saccharomyces cerevisiae. In this study, 26 fungal strains producing amylolytic activities that were more active at 30°C than at 60°C were isolated from 151 environmental samples. Fungal strain WZ99, producing extracellular amylolytic activities with the lowest optimal temperature at 40°C, was identified as Aspergillus tritici by analysis of morphological and molecular data. An extracellular glucoamylase was purified from A. tritici WZ99. The optimal pH of the enzyme was 4.0-5.0 and optimal temperature was 45°C. The glucoamylase was stable at pH 4.5-10.0 and below 40°C. Metal ions at four concentrations did not inhibit the enzyme activity. The glucoamylase contained a catalytic domain belonging to glycosyl hydrolase family 15 and thus was named as AtriGA15A. The enzyme shared the highest identity of 54% with a glucoamylase from Rasamsonia emersonii. This glucoamylase showing excellent comprehensive enzymatic characteristics might have potential applications in starch-based bioethanol production and starch processing.
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Affiliation(s)
- Liang Xian
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, China
| | - Jia-Xun Feng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, China.
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Maicas S, Caminero A, Martínez JP, Sentandreu R, Valentín E. The GCA1 gene encodes a glycosidase-like protein in the cell wall of Candida albicans. FEMS Yeast Res 2016; 16:fow032. [PMID: 27189368 DOI: 10.1093/femsyr/fow032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2016] [Indexed: 11/14/2022] Open
Abstract
Candida albicans Gca1p is a putative glucoamylase enzyme which contains 946 amino acids, 11 putative sites for N-glycosylation and 9 for O-glycosylation. Gca1p was identified in β-mercaptoethanol extracts from isolated cell walls of strain C. albicans SC5314 and it is involved in carbohydrate metabolism. The significance and the role of this protein within the cell wall structure were studied in the corresponding mutants. The homozygous mutant showed that GCA1 was not an essential gene for cell viability. Subsequent phenotypic analysis performed in the mutants obtained did not show significant difference in the behavior of mutant when compared with the wild strain SC5314. Zymoliase, Calcofluor White, Congo red, SDS, caffeine or inorganic compounds did not affect the integrity of the cell wall. No differences were observed when hyphal formation assays were carried out. However, an enzyme assay in the presence of substrate p-nitrophenyl-α-D-glucopyranoside enabled us to detect a significant decrease in glycosidase activity in the mutants compared with the parental strain, revealing the function of Gca1.
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Affiliation(s)
- Sergi Maicas
- Departament de Microbiologia i Ecologia, Facultat de Biologia, Universitat de València, 46100-E, Burjassot, Spain
| | - Antonio Caminero
- Departament de Microbiologia i Ecologia, Facultat de Farmàcia, Universitat de València, 46100-E, Burjassot, Spain
| | - José Pedro Martínez
- Departament de Microbiologia i Ecologia, Facultat de Farmàcia, Universitat de València, 46100-E, Burjassot, Spain
| | - Rafael Sentandreu
- Departament de Microbiologia i Ecologia, Facultat de Farmàcia, Universitat de València, 46100-E, Burjassot, Spain
| | - Eulogio Valentín
- Departament de Microbiologia i Ecologia, Facultat de Farmàcia, Universitat de València, 46100-E, Burjassot, Spain
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Adaptations of the Secretome of Candida albicans in Response to Host-Related Environmental Conditions. EUKARYOTIC CELL 2015; 14:1165-72. [PMID: 26453650 PMCID: PMC4664879 DOI: 10.1128/ec.00142-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The wall proteome and the secretome of the fungal pathogen Candida albicans help it to thrive in multiple niches of the human body. Mass spectrometry has allowed researchers to study the dynamics of both subproteomes. Here, we discuss some major responses of the secretome to host-related environmental conditions. Three β-1,3-glucan-modifying enzymes, Mp65, Sun41, and Tos1, are consistently found in large amounts in culture supernatants, suggesting that they are needed for construction and expansion of the cell wall β-1,3-glucan layer and thus correlate with growth and might serve as diagnostic biomarkers. The genes ENG1, CHT3, and SCW11, which encode an endoglucanase, the major chitinase, and a β-1,3-glucan-modifying enzyme, respectively, are periodically expressed and peak in M/G1. The corresponding protein abundances in the medium correlate with the degree of cell separation during single-yeast-cell, pseudohyphal, and hyphal growth. We also discuss the observation that cells treated with fluconazole, or other agents causing cell surface stress, form pseudohyphal aggregates. Fluconazole-treated cells secrete abundant amounts of the transglucosylase Phr1, which is involved in the accumulation of β-1,3-glucan in biofilms, raising the question whether this is a general response to cell surface stress. Other abundant secretome proteins also contribute to biofilm formation, emphasizing the important role of secretome proteins in this mode of growth. Finally, we discuss the relevance of these observations to therapeutic intervention. Together, these data illustrate that C. albicans actively adapts its secretome to environmental conditions, thus promoting its survival in widely divergent niches of the human body.
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Zohbi R, Wex B, Khalaf RA. Comparative proteomic analysis of a Candida albicans DSE1 mutant under filamentous and non-filamentous conditions. Yeast 2014; 31:441-8. [PMID: 25231799 DOI: 10.1002/yea.3039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 04/24/2014] [Accepted: 09/11/2014] [Indexed: 11/06/2022] Open
Abstract
Candida albicans is a common opportunistic pathogen that causes a variety of diseases in immunocompromised hosts. In a pathogen, cell wall proteins are important virulence factors. We previously characterized Dse1 as a cell wall protein necessary for virulence and resistance to cell surface-disrupting agents, such as Calcofluor white, chitin deposition, proper adhesion and biofilm formation. In the absence of decomplexation, our objectives were to investigate differential proteomic expression of a DSE1 mutant strain compared to the wild-type strain. The strains were grown under filamentous and non-filamentous conditions. The extracted cell proteome was subjected to tryptic digest, followed by generation of peptide profiles using MALDI-TOF MS. Generated peptide profiles were analysed and unique peaks for each strain and growth condition mined against a Candida database, allowing protein identification. The DSE1 mutant was shown to lack the chitin biosynthesis protein Chs5, explaining the previously observed decrease in chitin biosynthesis. The wild-type strain expressed Pra1, involved in pH response and zinc acquisition, Atg15, a lipase involved in virulence, and Sod1, required for oxidative stress tolerance, in addition to proteins involved in protein biosynthesis, explaining the increase in total protein content observed compared to the mutants strain. The mutant, on the other hand, expressed glucoamylase 1, a cell wall glycoprotein involved in carbohydrate metabolism cell wall degradation and biofilm formation. As such, MALDI-TOF MS is a reliable technique in identifying mutant-specific protein expression in C. albicans.
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Affiliation(s)
- Rasha Zohbi
- Department of Natural Sciences, Lebanese American University, Byblos, Lebanon
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Kumar P, Satyanarayana T. Microbial glucoamylases: characteristics and applications. Crit Rev Biotechnol 2009; 29:225-55. [DOI: 10.1080/07388550903136076] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Nobile CJ, Nett JE, Hernday AD, Homann OR, Deneault JS, Nantel A, Andes DR, Johnson AD, Mitchell AP. Biofilm matrix regulation by Candida albicans Zap1. PLoS Biol 2009; 7:e1000133. [PMID: 19529758 PMCID: PMC2688839 DOI: 10.1371/journal.pbio.1000133] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 05/12/2009] [Indexed: 01/06/2023] Open
Abstract
A biofilm is a surface-associated population of microorganisms embedded in a matrix of extracellular polymeric substances. Biofilms are a major natural growth form of microorganisms and the cause of pervasive device-associated infection. This report focuses on the biofilm matrix of Candida albicans, the major fungal pathogen of humans. We report here that the C. albicans zinc-response transcription factor Zap1 is a negative regulator of a major matrix component, soluble beta-1,3 glucan, in both in vitro and in vivo biofilm models. To understand the mechanistic relationship between Zap1 and matrix, we identified Zap1 target genes through expression profiling and full genome chromatin immunoprecipitation. On the basis of these results, we designed additional experiments showing that two glucoamylases, Gca1 and Gca2, have positive roles in matrix production and may function through hydrolysis of insoluble beta-1,3 glucan chains. We also show that a group of alcohol dehydrogenases Adh5, Csh1, and Ifd6 have roles in matrix production: Adh5 acts positively, and Csh1 and Ifd6, negatively. We propose that these alcohol dehydrogenases generate quorum-sensing aryl and acyl alcohols that in turn govern multiple events in biofilm maturation. Our findings define a novel regulatory circuit and its mechanism of control of a process central to infection.
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Affiliation(s)
- Clarissa J. Nobile
- Department of Microbiology, Columbia University, New York, New York, United States of America
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Jeniel E. Nett
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Aaron D. Hernday
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Oliver R. Homann
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Jean-Sebastien Deneault
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada
| | - Andre Nantel
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada
| | - David R. Andes
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Alexander D. Johnson
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Aaron P. Mitchell
- Department of Microbiology, Columbia University, New York, New York, United States of America
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
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Abstract
The Candida albicans cell wall maintains the structural integrity of the organism in addition to providing a physical contact interface with the environment. The major components of the cell wall are fibrillar polysaccharides and proteins. The proteins of the cell wall are the focus of this review. Three classes of proteins are present in the candidal cell wall. One group of proteins attach to the cell wall via a glycophosphatidylinositol remnant or by an alkali-labile linkage. A second group of proteins with N-terminal signal sequences but no covalent attachment sequences are secreted by the classical secretory pathway. These proteins may end up in the cell wall or in the extracellular space. The third group of proteins lack a secretory signal, and the pathway(s) by which they become associated with the surface is unknown. Potential constituents of the first two classes have been predicted from analysis of genome sequences. Experimental analyses have identified members of all three classes. Some members of each class selected for consideration of confirmed or proposed function, phenotypic analysis of a mutant, and regulation by growth conditions and transcription factors are discussed in more detail.
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Latorre-García L, Adam AC, Manzanares P, Polaina J. Improving the amylolytic activity of Saccharomyces cerevisiae glucoamylase by the addition of a starch binding domain. J Biotechnol 2005; 118:167-76. [PMID: 15963591 DOI: 10.1016/j.jbiotec.2005.03.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 01/26/2005] [Accepted: 03/18/2005] [Indexed: 10/25/2022]
Abstract
Glucoamylase produced by amylolytic strains of Saccharomyces cerevisiae (var. diastaticus) lacks a starch binding domain that is present in homologous glucoamylases from Aspergillus niger and other filamentous fungi. The absence of the binding domain makes the enzyme inefficient against raw starch and hence unsuitable for most biotechnological applications. We have constructed a hybrid glucoamylase-encoding gene by in-frame fusion of the S. cerevisiae STA1 gene and DNA fragment that encodes the starch binding domain of A. niger glucoamylase. The hybrid enzyme resulting from expression of the chimeric gene in S. cerevisiae has substrate binding capability and hydrolyses insoluble starch, properties not present in the original yeast enzyme.
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Affiliation(s)
- Lorena Latorre-García
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Apartado de Correos (CSIC) 73, E46100-Burjassot (Valencia), Spain, Paterna, Valencia, Spain
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Hostinová E, Solovicová A, Gasperík J. Cloning and expression of a gene for an alpha-glucosidase from Saccharomycopsis fibuligera homologous to family GH31 of yeast glucoamylases. Appl Microbiol Biotechnol 2005; 69:51-6. [PMID: 15821912 DOI: 10.1007/s00253-005-1971-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Revised: 03/15/2005] [Accepted: 03/20/2005] [Indexed: 10/25/2022]
Abstract
Cloning of cDNA encoding an alpha-glucosidase from the dimorphous yeast Saccharomycopsis fibuligera and characterization of the gene product were performed. The cDNA of the putative alpha-glucosidase gene consists of 2,886 bp, which includes an open reading frame encoding a 19 amino acid signal peptide at the N-terminal end and a 944 amino acid mature protein with a predicted molecular mass of 105.4 kDa and pI value of 4.52. The deduced amino acid sequence shows a high degree of identity (70%) with two yeast glucoamylases, namely, the extracellular glucoamylase Gam from Schwanniomyces occidentalis and the cell surface glucoamylase Gca from Candida albicans. The recombinant product, synthesized in Saccharomyces cerevisiae, is localized on the cell surface and hydrolyses maltooligosaccharides exclusively without the ability to digest soluble starch, which is consistent with the specificity characteristic of alpha-glucosidase, EC. 3.2.1.20.
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Affiliation(s)
- Eva Hostinová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 84551 Bratislava, Slovakia.
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Nguyen MH, Cheng S, Clancy CJ. Assessment of Candida albicans genes expressed during infections as a tool to understand pathogenesis. Med Mycol 2004; 42:293-304. [PMID: 15473353 DOI: 10.1080/13693780410001722485] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Candida albicans is the most common fungal opportunistic pathogen of humans and causes mucocutaneous, bloodstream and deep organ infections. Screening for C. albicans genes that are preferentially expressed within infected hosts represents a strategy to identify novel virulence factors and define global expression patterns relevant to pathogenesis. Until recently, C. albicans has not been amenable to screening using existing technologies. This has begun to change with the development of new molecular genetic tools and the sequencing of the C. albicans genome. In this paper, we review studies using recently developed techniques to identify genes expressed by C. albicans during infections, as well as work from our laboratory using a human antibody-based strategy. Along with others, we have shown that selected in vivo expressed genes encode known and previously unrecognized candidal virulence factors. Future studies in this area will identify additional novel virulence factors, as well as advance our understanding of pathogenesis.
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Affiliation(s)
- M Hong Nguyen
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA
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