1
|
Cong H, Li C, Wang Y, Zhang Y, Ma D, Li L, Jiang J. The Mechanism of Transcription Factor Swi6 in Regulating Growth and Pathogenicity of Ceratocystis fimbriata: Insights from Non-Targeted Metabolomics. Microorganisms 2023; 11:2666. [PMID: 38004677 PMCID: PMC10673406 DOI: 10.3390/microorganisms11112666] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/22/2023] [Accepted: 10/25/2023] [Indexed: 11/26/2023] Open
Abstract
Ceratocystis fimbriata (C. fimbriata) is a notorious pathogenic fungus that causes sweet potato black rot disease. The APSES transcription factor Swi6 in fungi is located downstream of the cell wall integrity (CWI)-mitogen-activated protein kinase (MAPK) signaling pathway and has been identified to be involved in cell wall integrity and virulence in several filamentous pathogenic fungi. However, the specific mechanisms by which Swi6 regulates the growth and pathogenicity of plant pathogenic fungi remain elusive. In this study, the SWI6 deletion mutants and complemented strains of C. fimbriata were generated. Deletion of Swi6 in C. fimbriata resulted in aberrant growth patterns. Pathogenicity assays on sweet potato storage roots revealed a significant decrease in virulence in the mutant. Non-targeted metabolomic analysis using LC-MS identified a total of 692 potential differentially accumulated metabolites (PDAMs) in the ∆Cfswi6 mutant compared to the wild type, and the results of KEGG enrichment analysis demonstrated significant enrichment of PDAMs within various metabolic pathways, including amino acid metabolism, lipid metabolism, nucleotide metabolism, GPI-anchored protein synthesis, and ABC transporter metabolism. These metabolic pathways were believed to play a crucial role in mediating the growth and pathogenicity of C. fimbriata through the regulation of CWI. Firstly, the deletion of the SWI6 gene led to abnormal amino acid and lipid metabolism, potentially exacerbating energy storage imbalance. Secondly, significant enrichment of metabolites related to GPI-anchored protein biosynthesis implied compromised cell wall integrity. Lastly, disruption of ABC transport protein metabolism may hinder intracellular transmembrane transport. Importantly, this study represents the first investigation into the potential regulatory mechanisms of SWI6 in plant filamentous pathogenic fungi from a metabolic perspective. The findings provide novel insights into the role of SWI6 in the growth and virulence of C. fimbriata, highlighting its potential as a target for controlling this pathogen.
Collapse
Affiliation(s)
- Hao Cong
- The Key Laboratory of Biotechnology for Medicinal and Edible Plant Resources of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (H.C.); (C.L.); (Y.W.); (Y.Z.)
| | - Changgen Li
- The Key Laboratory of Biotechnology for Medicinal and Edible Plant Resources of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (H.C.); (C.L.); (Y.W.); (Y.Z.)
| | - Yiming Wang
- The Key Laboratory of Biotechnology for Medicinal and Edible Plant Resources of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (H.C.); (C.L.); (Y.W.); (Y.Z.)
| | - Yongjing Zhang
- The Key Laboratory of Biotechnology for Medicinal and Edible Plant Resources of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (H.C.); (C.L.); (Y.W.); (Y.Z.)
| | - Daifu Ma
- Chinese Academy of Agricultural Sciences Sweet Potato Research Institute, Xuzhou 221131, China;
| | - Lianwei Li
- The Key Laboratory of Biotechnology for Medicinal and Edible Plant Resources of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (H.C.); (C.L.); (Y.W.); (Y.Z.)
| | - Jihong Jiang
- The Key Laboratory of Biotechnology for Medicinal and Edible Plant Resources of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (H.C.); (C.L.); (Y.W.); (Y.Z.)
| |
Collapse
|
2
|
ATP-Binding Cassette (ABC) Transporters in Fusarium Specific Mycoparasite Sphaerodes mycoparasitica during Biotrophic Mycoparasitism. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12157641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent transcriptomic profiling has revealed importance membrane transporters such as ATP-binding cassette (ABC) transporters in fungal necrotrophic mycoparasites. In this study, RNA-Seq allowed rapid detection of ABC transcripts involved in biotrophic mycoparasitism of Sphaerodes mycoparasitica against the phytopathogenic and mycotoxigenic Fusarium graminearum host, the causal agent of Fusarium head blight (FHB). Transcriptomic analyses of highly expressed S. mycoparasitica genes, and their phylogenetic relationships with other eukaryotic fungi, portrayed the ABC transporters’ evolutionary paths towards biotrophic mycoparasitism. Prior to the in silico phylogenetic analyses, transmission electron microscopy (TEM) was used to confirm the formation of appressorium/haustorium infection structures in S. mycoparasitica during early (1.5 d and 3.5 d) stages of mycoparasitism. Transcripts encoding biotrophy-associated secreted proteins did uncover the enrolment of ABC transporter genes in this specific biocontrol mode of action, while tandem ABC and BUB2 (non-ABC) transcripts seemed to be proper for appressorium development. The next-generation HiSeq transcriptomic profiling of the mycoparasitic hypha samples, revealed 81 transcripts annotated to ABC transporters consisting of a variety of ABC-B (14%), ABC-C (22%), and ABC-G (23%), and to ABC-A, ABC-F, aliphatic sulfonates importer (TC 3.A.1.17.2), BtuF, ribose importer (TC 3.A.1.2.1), and unknown families. The most abundant transcripts belonged to the multidrug resistance exporter (TC 3.A.1.201) subfamily of the ABC-B family, the conjugate transporter (TC 3.A.1.208) subfamily of the ABC-C family, and the pleiotropic drug resistance (PDR) (TC 3.A.1.205) subfamily of the ABC-G family. These findings highlight the significance of ABC transporter genes that control cellular detoxification against toxic substances (e.g., chemical pesticides and mycotoxins) in sustaining a virulence of S. mycoparasitica for effective biotrophic mycoparasitism on the F. graminearum host. The findings of this study provide clues to better understand the biotrophic mycoparasitism of S. mycoparasitica interacting with the Fusarium host, which implies that the ABC transporter group of key proteins is involved in the mycoparasite’s virulence and multidrug resistance to toxic substances including cellular detoxification.
Collapse
|
3
|
Oliveira NK, Bhattacharya S, Gambhir R, Joshi M, Fries BC. Novel ABC Transporter Associated with Fluconazole Resistance in Aging of Cryptococcus neoformans. J Fungi (Basel) 2022; 8:677. [PMID: 35887434 PMCID: PMC9320417 DOI: 10.3390/jof8070677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 11/27/2022] Open
Abstract
Cryptococcus neoformans causes meningoencephalitis in immunocompromised individuals, which is treated with fluconazole (FLC) monotherapy when resources are limited. This can lead to azole resistance, which can be mediated by overexpression of ABC transporters, a class of efflux pumps. ABC pump-mediated efflux of FLC is also augmented in 10-generation old C. neoformans cells. Here, we describe a new ABC transporter Afr3 (CNAG_06909), which is overexpressed in C. neoformans cells of advanced generational age that accumulate during chronic infection. The Δafr3 mutant strain showed higher FLC susceptibility by FLC E-Test strip testing and also by a killing test that measured survival after 3 h FLC exposure. Furthermore, Δafr3 cells exhibited lower Rhodamine 6G efflux compared to the H99 wild-type cells. Afr3 was expressed in the Saccharomyces cerevisiae ADΔ strain, which lacks several drug transporters, thus reducing background transport. The ADΔ + Afr3 strain demonstrated a higher efflux with both Rhodamine 6G and Nile red, and a higher FLC resistance. Afr3-GFP localized in the plasma membrane of the ADΔ + Afr3 strain, further highlighting its importance as an efflux pump. Characterization of the Δafr3 mutant revealed unattenuated growth but a prolongation (29%) of the replicative life span. In addition, Δafr3 exhibited decreased resistance to macrophage killing and attenuated virulence in the Galleria mellonella infection model. In summary, our data indicate that a novel ABC pump Afr3, which is upregulated in C. neoformans cells of advanced age, may contribute to their enhanced FLC tolerance, by promoting drug efflux. Lastly, its role in macrophage resistance may also contribute to the selection of older C. neoformans cells during chronic infection.
Collapse
Affiliation(s)
- Natalia Kronbauer Oliveira
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA;
| | - Somanon Bhattacharya
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA;
| | - Rina Gambhir
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (R.G.); (M.J.)
| | - Manav Joshi
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; (R.G.); (M.J.)
| | - Bettina C. Fries
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA;
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA;
- Veterans Administration Medical Center, Northport, NY 11768, USA
| |
Collapse
|
4
|
A Fungal Transcription Regulator of Vacuolar Function Modulates Candida albicans Interactions with Host Epithelial Cells. mBio 2021; 12:e0302021. [PMID: 34781731 PMCID: PMC8593675 DOI: 10.1128/mbio.03020-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microorganisms typically maintain cellular homeostasis despite facing large fluctuations in their surroundings. Microbes that reside on human mucosal surfaces may experience significant variations in nutrient and ion availability as well as pH. Whether the mechanisms employed by these microbial cells to sustain homeostasis directly impact on the interplay with the host’s mucosae remains unclear. Here, we report that the previously uncharacterized transcription regulator ZCF8 in the human-associated yeast Candida albicans maintains vacuole homeostasis when the fungus faces fluctuations in nitrogen. Genome-wide identification of genes directly regulated by Zcf8p followed by fluorescence microscopy to define their subcellular localization uncovered the fungal vacuole as a top target of Zcf8p regulation. Deletion and overexpression of ZCF8 resulted in alterations in vacuolar morphology and luminal pH and rendered the fungus resistant or susceptible to nigericin and brefeldin A, two drugs that impair vacuole and associated functions. Furthermore, we establish that the regulator modulates C. albicans attachment to epithelial cells in a manner that depends on the status of the fungal vacuole. Our findings, therefore, suggest that fungal vacuole physiology regulation is intrinsically linked to, and shapes to a significant extent, the physical interactions that Candida cells establish with mammalian mucosal surfaces.
Collapse
|
5
|
Wu X, Tian H, Li L, Guan C, Zhang Z. Higher Cd-accumulating oilseed rape has stronger Cd tolerance due to stronger Cd fixation in pectin and hemicellulose and higher Cd chelation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 285:117218. [PMID: 33933876 DOI: 10.1016/j.envpol.2021.117218] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Oilseed rape (Brassica napus) has potential as a hyperaccumulator in the phytoremediation of cadmium (Cd)-contaminated soils. Oilseed rape varieties with higher Cd accumulation ability and Cd tolerance are ideal candidates for the hyperaccumulation of excess Cd. To explore the physiological and molecular mechanisms underlying Cd tolerance and high Cd accumulation in oilseed rape leaves, we examined two genotypes, "BN067" (Cd-sensitive with lower Cd accumulation in leaves) and "BN06" (Cd-tolerant with higher Cd accumulation in leaves). We characterized the physiological morphology, structure, subcellular distribution of Cd, cell wall components, cell chelates, and the transcriptional levels of the related genes. Greater Cd accumulation was observed in the cell walls and vacuoles of Cd-tolerant leaves, reducing Cd toxicity to the lamellar structure of the chloroplast thylakoid and leaf stomata. Higher expression of PMEs genes and lower expression of pectin methylesterase inhibitors (PMEI) genes improved pectin methylesterase (PME) activity in leaves of Cd-tolerant genotype. Stronger demethylation of pectin along with higher pectin and hemicellulose levels induced by lower pectinase and hemicellulose activities in the leaves of the Cd-tolerant genotype, resulting in higher Cd retention in the cell walls. Under Cd toxicity, higher Cd sequestration within the vacuoles of Cd-tolerant leaves was closely related to greater accumulation of Cd chelates with stronger biosynthesis in protoplasts. The results highlight the importance of using hyperaccumulation by plants to remediate our environment, and also provide a theoretical basis for the development of Cd-tolerant varieties.
Collapse
Affiliation(s)
- Xiuwen Wu
- College of Resources and Environmental Sciences, Qingdao Agricultural University, Qingdao, China.
| | - Hui Tian
- College of Resources and Environmental Sciences, Qingdao Agricultural University, Qingdao, China; Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Li Li
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Chunyun Guan
- National Center of Oilseed Crops Improvement, Hunan Branch, Changsha, China
| | - Zhenhua Zhang
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China.
| |
Collapse
|
6
|
Kumari S, Kumar M, Gaur NA, Prasad R. Multiple roles of ABC transporters in yeast. Fungal Genet Biol 2021; 150:103550. [PMID: 33675986 DOI: 10.1016/j.fgb.2021.103550] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 01/29/2021] [Accepted: 02/25/2021] [Indexed: 12/20/2022]
Abstract
The ATP binding cassette (ABC) transporters, first discovered as high-affinity nutrient importers in bacteria, rose to prominence when their ability to confer multidrug resistance (MDR) to cancer cells was realized. The most characterized human permeability glycoprotein (P-gp) is a dominant exporter of anti-cancer drugs and its overexpression is directly linked to MDR. The overexpression of drug efflux pumps belonging to the ABC superfamily is also a frequent cause of resistance to antifungals. Fungi has a battery of ABC proteins, but in variable numbers and at different subcellular locations. These proteins perform many critical functions, from serving as gatekeepers for xenobiotic cleansing to translocating various structurally unrelated cargoes, including lipids, fatty acids, ions, peptides, sterols, metabolites and toxins. Their emerging additional roles in cellular physiology and virulence call for attention to analyze and re-examine their divergent functions in yeast. In brief, this review traces the history of ABC transporters in yeast and discusses their typical physiological functions that go beyond their well-known role as antifungal drug efflux pumps.
Collapse
Affiliation(s)
- Sonam Kumari
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Mohit Kumar
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India; Amity Institute of Integrative Science and Health, Amity Institute of Biotechnology, Amity University Gurgaon, 122413 Haryana, India
| | - Naseem A Gaur
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.
| | - Rajendra Prasad
- Amity Institute of Integrative Science and Health, Amity Institute of Biotechnology, Amity University Gurgaon, 122413 Haryana, India.
| |
Collapse
|
7
|
Thomas G, Bain JM, Budge S, Brown AJP, Ames RM. Identifying Candida albicans Gene Networks Involved in Pathogenicity. Front Genet 2020; 11:375. [PMID: 32391057 PMCID: PMC7193023 DOI: 10.3389/fgene.2020.00375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/26/2020] [Indexed: 11/17/2022] Open
Abstract
Candida albicans is a normal member of the human microbiome. It is also an opportunistic pathogen, which can cause life-threatening systemic infections in severely immunocompromized individuals. Despite the availability of antifungal drugs, mortality rates of systemic infections are high and new drugs are needed to overcome therapeutic challenges including the emergence of drug resistance. Targeting known disease pathways has been suggested as a promising avenue for the development of new antifungals. However, <30% of C. albicans genes are verified with experimental evidence of a gene product, and the full complement of genes involved in important disease processes is currently unknown. Tools to predict the function of partially or uncharacterized genes and generate testable hypotheses will, therefore, help to identify potential targets for new antifungal development. Here, we employ a network-extracted ontology to leverage publicly available transcriptomics data and identify potential candidate genes involved in disease processes. A subset of these genes has been phenotypically screened using available deletion strains and we present preliminary data that one candidate, PEP8, is involved in hyphal development and immune evasion. This work demonstrates the utility of network-extracted ontologies in predicting gene function to generate testable hypotheses that can be applied to pathogenic systems. This could represent a novel first step to identifying targets for new antifungal therapies.
Collapse
Affiliation(s)
- Graham Thomas
- Biosciences, University of Exeter, Exeter, United Kingdom
| | - Judith M Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Susan Budge
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Alistair J P Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,MRC Centre for Medical Mycology at the University of Exeter, Biosciences, University of Exeter, Exeter, United Kingdom
| | - Ryan M Ames
- Biosciences, University of Exeter, Exeter, United Kingdom
| |
Collapse
|
8
|
Rizzo J, Stanchev LD, da Silva VK, Nimrichter L, Pomorski TG, Rodrigues ML. Role of lipid transporters in fungal physiology and pathogenicity. Comput Struct Biotechnol J 2019; 17:1278-1289. [PMID: 31921394 PMCID: PMC6944739 DOI: 10.1016/j.csbj.2019.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/20/2019] [Accepted: 09/02/2019] [Indexed: 02/08/2023] Open
Abstract
The fungal cell wall and membrane are the most common targets of antifungal agents, but the potential of membrane lipid organization in regulating drug-target interactions has yet to be investigated. Energy-dependent lipid transporters have been recently associated with virulence and drug resistance in many pathogenic fungi. To illustrate this view, we discuss (i) the structural and biological aspects of ATP-driven lipid transporters, comprising P-type ATPases and ATP-binding cassette transporters, (ii) the role of these transporters in fungal physiology and virulence, and (iii) the potential of lipid transporters as targets for the development of novel antifungals. These recent observations indicate that the lipid-trafficking machinery in fungi is a promising target for studies on physiology, pathogenesis and drug development.
Collapse
Affiliation(s)
- Juliana Rizzo
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Lyubomir Dimitrov Stanchev
- Department of Molecular Biochemistry, Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780 Bochum, Germany
- Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C,Denmark
| | - Vanessa K.A. da Silva
- Programa de Pós-Graduação em Biologia Parasitária do Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | - Leonardo Nimrichter
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780 Bochum, Germany
- Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C,Denmark
| | - Marcio L. Rodrigues
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba, Brazil
| |
Collapse
|
9
|
Vacuolar Sequestration of Azoles, a Novel Strategy of Azole Antifungal Resistance Conserved across Pathogenic and Nonpathogenic Yeast. Antimicrob Agents Chemother 2019; 63:AAC.01347-18. [PMID: 30642932 DOI: 10.1128/aac.01347-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/29/2018] [Indexed: 11/20/2022] Open
Abstract
Target alteration and overproduction and drug efflux through overexpression of multidrug transporters localized in the plasma membrane represent the conventional mechanisms of azole antifungal resistance. Here, we identify a novel conserved mechanism of azole resistance not only in the budding yeast Saccharomyces cerevisiae but also in the pathogenic yeast Candida albicans We observed that the vacuolar-membrane-localized, multidrug resistance protein (MRP) subfamily, ATP-binding cassette (ABC) transporter of S. cerevisiae, Ybt1, could import azoles into vacuoles. Interestingly, the Ybt1 homologue in C. albicans, Mlt1p, could also fulfill this function. Evidence that the process is energy dependent comes from the finding that a Mlt1p mutant version made by converting a critical lysine residue in the Walker A motif of nucleotide-binding domain 1 (required for ATP hydrolysis) to alanine (K710A) was not able to transport azoles. Additionally, we have shown that, as for other eukaryotic MRP subfamily members, deletion of the conserved phenylalanine amino acid at position 765 (F765Δ) results in mislocalization of the Mlt1 protein; this mislocalized protein was devoid of the azole-resistant attribute. This finding suggests that the presence of this protein on vacuolar membranes is an important factor in azole resistance. Further, we report the importance of conserved residues, because conversion of two serines (positions 973 and 976, in the regulatory domain and in the casein kinase I [CKI] consensus sequence, respectively) to alanine severely affected the drug resistance. Hence, the present study reveals vacuolar sequestration of azoles by the ABC transporter Ybt1 and its homologue Mlt1 as an alternative strategy to circumvent drug toxicity among pathogenic and nonpathogenic yeasts.
Collapse
|
10
|
Yin Y, Wang Z, Cheng D, Chen X, Chen Y, Ma Z. The ATP-binding protein FgArb1 is essential for penetration, infectious and normal growth of Fusarium graminearum. THE NEW PHYTOLOGIST 2018; 219:1447-1466. [PMID: 29932228 DOI: 10.1111/nph.15261] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
ATP-binding cassette (ABC) transporters act mainly to transport compounds across cellular membranes and are important for diverse biological processes. However, their roles in pathogenesis have not been well-characterized in Fusarium graminearum. Sixty F. graminearum ABC protein genes were functionally characterized. Among them, FgArb1 regulates normal growth and importantly is essential for pathogenicity. Thus, the regulatory mechanisms of FgArb1 in pathogenicity were analyzed in this study. FgArb1 interacts with the mitogen-activated protein kinase (MAPK) FgSte7, and partially modulates plant penetration by regulating the phosphorylation of FgGpmk1 (the downstream kinase of FgSte7). The FgArb1 mutant exhibited dramatically reduced infective growth within wounded host tissues, likely resulting from its increased sensitivity to oxidative stresses, defective cell wall integrity and reduced deoxynivalenol (DON) production. FgArb1 also is important for the production of sexual and asexual spores that are important propagules for plant infection. In addition, FgArb1 is involved in the regulation of protein biosynthesis through impeding nuclear export of small ribosomal subunit. Finally, acetylation modification at sites K28, K65, K341 and K525 in FgArb1 is required for its biological functions. Taken together, results of this study provide a novel insight into functions of the ABC transporter in fungal pathogenesis.
Collapse
Affiliation(s)
- Yanni Yin
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Zhihui Wang
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Danni Cheng
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Xiang Chen
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Yun Chen
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| |
Collapse
|
11
|
Watanasrisin W, Iwatani S, Oura T, Tomita Y, Ikushima S, Chindamporn A, Niimi M, Niimi K, Lamping E, Cannon RD, Kajiwara S. Identification and characterization ofCandida utilismultidrug efflux transporterCuCdr1p. FEMS Yeast Res 2016; 16:fow042. [DOI: 10.1093/femsyr/fow042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2016] [Indexed: 11/12/2022] Open
|
12
|
Pleiotropic effects of the vacuolar ABC transporter MLT1 of Candida albicans on cell function and virulence. Biochem J 2016; 473:1537-52. [PMID: 27026051 PMCID: PMC4888455 DOI: 10.1042/bcj20160024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/29/2016] [Indexed: 01/14/2023]
Abstract
Among the several mechanisms that contribute to MDR (multidrug resistance), the overexpression of drug-efflux pumps belonging to the ABC (ATP-binding cassette) superfamily is the most frequent cause of resistance to antifungal agents. The multidrug transporter proteins Cdr1p and Cdr2p of the ABCG subfamily are major players in the development of MDR in Candida albicans. Because several genes coding for ABC proteins exist in the genome of C. albicans, but only Cdr1p and Cdr2p have established roles in MDR, it is implicit that the other members of the ABC family also have alternative physiological roles. The present study focuses on an ABC transporter of C. albicans, Mlt1p, which is localized in the vacuolar membrane and specifically transports PC (phosphatidylcholine) into the vacuolar lumen. Transcriptional profiling of the mlt1∆/∆ mutant revealed a down-regulation of the genes involved in endocytosis, oxidoreductase activity, virulence and hyphal development. High-throughput MS-based lipidome analysis revealed that the Mlt1p levels affect lipid homoeostasis and thus lead to a plethora of physiological perturbations. These include a delay in endocytosis, inefficient sequestering of reactive oxygen species (ROS), defects in hyphal development and attenuated virulence. The present study is an emerging example where new and unconventional roles of an ABC transporter are being identified.
Collapse
|
13
|
Bioinformatic survey of ABC transporters in dermatophytes. Gene 2016; 576:466-75. [DOI: 10.1016/j.gene.2015.10.064] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 10/23/2015] [Accepted: 10/25/2015] [Indexed: 11/19/2022]
|
14
|
Candida Efflux ATPases and Antiporters in Clinical Drug Resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 892:351-376. [PMID: 26721282 DOI: 10.1007/978-3-319-25304-6_15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An enhanced expression of genes encoding ATP binding cassette (ABC) and major facilitator superfamily (MFS) transport proteins are known to contribute to the development of tolerance to antifungals in pathogenic yeasts. For example, the azole resistant (AR) clinical isolates of the opportunistic human fungal pathogen Candida albicans show an overexpression of CDR1 and/or CaMDR1 belonging to ABC and MFS, superfamilies, respectively. The reduced accumulation (due to rapid efflux) of drugs in AR isolates confirms the role of efflux pump proteins in the development of drug tolerance. Considering the importance of major multidrug transporters, the focus of recent research has been to understand the structure and function of these proteins which could help to design inhibitors/modulators of these pump proteins. This chapter focuses on some aspects of the structure and function of yeast transporter proteins particularly in relation to MDR in Candida.
Collapse
|
15
|
Abstract
In the light of multidrug resistance (MDR) among pathogenic microbes and cancer cells, membrane transporters have gained profound clinical significance. Chemotherapeutic failure, by far, has been attributed mainly to the robust and diverse array of these proteins, which are omnipresent in every stratum of the living world. Candida albicans, one of the major fungal pathogens affecting immunocompromised patients, also develops MDR during the course of chemotherapy. The pivotal membrane transporters that C. albicans has exploited as one of the strategies to develop MDR belongs to either the ATP binding cassette (ABC) or the major facilitator superfamily (MFS) class of proteins. The ABC transporter Candida drug resistance 1 protein (Cdr1p) is a major player among these transporters that enables the pathogen to outplay the battery of antifungals encountered by it. The promiscuous Cdr1 protein fulfills the quintessential need of a model to study molecular mechanisms of multidrug transporter regulation and structure-function analyses of asymmetric ABC transporters. In this review, we cover the highlights of two decades of research on Cdr1p that has provided a platform to study its structure-function relationships and regulatory circuitry for a better understanding of MDR not only in yeast but also in other organisms.
Collapse
|
16
|
Cannon R, Holmes A. Learning the ABC of oral fungal drug resistance. Mol Oral Microbiol 2015; 30:425-37. [DOI: 10.1111/omi.12109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2015] [Indexed: 01/07/2023]
Affiliation(s)
- R.D. Cannon
- Sir John Walsh Research Institute; University of Otago; Dunedin New Zealand
| | - A.R. Holmes
- Sir John Walsh Research Institute; University of Otago; Dunedin New Zealand
| |
Collapse
|
17
|
Bernardo SM, Allen CP, Waller A, Young SM, Oprea T, Sklar LA, Lee SA. An automated high-throughput cell-based multiplexed flow cytometry assay to identify novel compounds to target Candida albicans virulence-related proteins. PLoS One 2014; 9:e110354. [PMID: 25350399 PMCID: PMC4211665 DOI: 10.1371/journal.pone.0110354] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 09/18/2014] [Indexed: 11/19/2022] Open
Abstract
Although three major classes of systemic antifungal agents are clinically available, each is characterized by important limitations. Thus, there has been considerable ongoing effort to develop novel and repurposed agents for the therapy of invasive fungal infections. In an effort to address these needs, we developed a novel high-throughput, multiplexed screening method that utilizes small molecules to probe candidate drug targets in the opportunistic fungal pathogen Candida albicans. This method is amenable to high-throughput automated screening and is based upon detection of changes in GFP levels of individually tagged target proteins. We first selected four GFP-tagged membrane-bound proteins associated with virulence or antifungal drug resistance in C. albicans. We demonstrated proof-of-principle that modulation of fluorescence intensity can be used to assay the expression of specific GFP-tagged target proteins to inhibitors (and inducers), and this change is measurable within the HyperCyt automated flow cytometry sampling system. Next, we generated a multiplex of differentially color-coded C. albicans strains bearing C-terminal GFP-tags of each gene encoding candidate drug targets incubated in the presence of small molecules from the Prestwick Chemical Library in 384-well microtiter plate format. Following incubation, cells were sampled through the HyperCyt system and modulation of protein levels, as indicated by changes in GFP-levels of each strain, was used to identify compounds of interest. The hit rate for both inducers and inhibitors identified in the primary screen did not exceed 1% of the total number of compounds in the small-molecule library that was probed, as would be expected from a robust target-specific, high-throughput screening campaign. Secondary assays for virulence characteristics based on null mutant strains were then used to further validate specificity. In all, this study presents a method for the identification and verification of new antifungal drugs targeted to fungal virulence proteins using C. albicans as a model fungal pathogen.
Collapse
Affiliation(s)
- Stella M. Bernardo
- Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, United States of America
- Division of Infectious Diseases, University of New Mexico Health Science Center, Albuquerque, NM, United States of America
| | - Christopher P. Allen
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, United States of America
| | - Anna Waller
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, United States of America
| | - Susan M. Young
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, United States of America
| | - Tudor Oprea
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, United States of America
| | - Larry A. Sklar
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, United States of America
| | - Samuel A. Lee
- Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, United States of America
- Division of Infectious Diseases, University of New Mexico Health Science Center, Albuquerque, NM, United States of America
- * E-mail:
| |
Collapse
|
18
|
Identification of genomic binding sites for Candida glabrata Pdr1 transcription factor in wild-type and ρ0 cells. Antimicrob Agents Chemother 2014; 58:6904-12. [PMID: 25199772 DOI: 10.1128/aac.03921-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The fungal pathogen Candida glabrata is an emerging cause of candidiasis in part owing to its robust ability to acquire tolerance to the major clinical antifungal drug fluconazole. Similar to the related species Candida albicans, C. glabrata most typically gains azole tolerance via transcriptional induction of a suite of resistance genes, including a locus encoding an ABCG-type ATP-binding cassette (ABC) transporter that is referred to as CDR1 in Candida species. In C. glabrata, CDR1 expression is controlled primarily by the activity of a transcriptional activator protein called Pdr1. Strains exhibiting reduced azole susceptibility often contain substitution mutations in PDR1 that in turn lead to elevated mRNA levels of target genes with associated azole resistance. Pdr1 activity is also induced upon loss of the mitochondrial genome status and upon challenge by azole drugs. While extensive analyses of the transcriptional effects of Pdr1 have identified a number of genes that are regulated by this factor, we cannot yet separate direct from indirect target genes. Here we used chromatin immunoprecipitation (ChIP) coupled with high-throughput sequencing (ChIP-seq) to identify the promoters and associated genes directly regulated by Pdr1. These genes include many that are shared with the yeast Saccharomyces cerevisiae but others that are unique to C. glabrata, including the ABC transporter-encoding locus YBT1, genes involved in DNA repair, and several others. These data provide the outline for understanding the primary response genes involved in production of Pdr1-dependent azole resistance in C. glabrata.
Collapse
|
19
|
Prasad R, Rawal MK. Efflux pump proteins in antifungal resistance. Front Pharmacol 2014; 5:202. [PMID: 25221515 PMCID: PMC4148622 DOI: 10.3389/fphar.2014.00202] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/13/2014] [Indexed: 11/13/2022] Open
Abstract
It is now well-known that the enhanced expression of ATP binding cassette (ABC) and major facilitator superfamily (MFS) proteins contribute to the development of tolerance to antifungals in yeasts. For example, the azole resistant clinical isolates of the opportunistic human fungal pathogen Candida albicans show an overexpression of Cdr1p and/or CaMdr1p belonging to ABC and MFS superfamilies, respectively. Hence, azole resistant isolates display reduced accumulation of therapeutic drug due to its rapid extrusion and that facilitates its survival. Considering the importance of major antifungal transporters, the focus of recent research has been to understand the structure and function of these proteins to design inhibitors/modulators to block the pump protein activity so that the drug already in use could again sensitize resistant yeast cells. The review focuses on the structure and function of ABC and MFS transporters of Candida to highlight the recent advancement in the field.
Collapse
Affiliation(s)
- Rajendra Prasad
- Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University New Delhi, India
| | - Manpreet K Rawal
- Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University New Delhi, India
| |
Collapse
|
20
|
Johnston DA, Tapia AL, Eberle KE, Palmer GE. Three prevacuolar compartment Rab GTPases impact Candida albicans hyphal growth. EUKARYOTIC CELL 2013; 12:1039-50. [PMID: 23709183 PMCID: PMC3697461 DOI: 10.1128/ec.00359-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 05/20/2013] [Indexed: 11/20/2022]
Abstract
Disruption of vacuolar biogenesis in the pathogenic yeast Candida albicans causes profound defects in polarized hyphal growth. However, the precise vacuolar pathways involved in yeast-hypha differentiation have not been determined. Previously we focused on Vps21p, a Rab GTPase involved in directing vacuolar trafficking through the late endosomal prevacuolar compartment (PVC). Herein, we identify two additional Vps21p-related GTPases, Ypt52p and Ypt53p, that colocalize with Vps21p and can suppress the hyphal defects of the vps21Δ/Δ mutant. Phenotypic analysis of gene deletion strains revealed that loss of both VPS21 and YPT52 causes synthetic defects in endocytic trafficking to the vacuole, as well as delivery of the virulence-associated vacuolar membrane protein Mlt1p from the Golgi compartment. Transcription of all three GTPase-encoding genes is increased under hyphal growth conditions, and overexpression of the transcription factor Ume6p is sufficient to increase the transcription of these genes. While only the vps21Δ/Δ single mutant has hyphal growth defects, these were greatly exacerbated in a vps21Δ/Δ ypt52Δ/Δ double mutant. On the basis of relative expression levels and phenotypic analysis of gene deletion strains, Vps21p is the most important of the three GTPases, followed by Ypt52p, while Ypt53p has an only marginal impact on C. albicans physiology. Finally, disruption of a nonendosomal AP-3-dependent vacuolar trafficking pathway in the vps21Δ/Δ ypt52Δ/Δ mutant, further exacerbated the stress and hyphal growth defects. These findings underscore the importance of membrane trafficking through the PVC in sustaining the invasive hyphal growth form of C. albicans.
Collapse
Affiliation(s)
- Douglas A Johnston
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, Louisiana, USA
| | | | | | | |
Collapse
|
21
|
Abstract
All fungal genomes harbour numerous ABC (ATP-binding cassette) proteins located in various cellular compartments such as the plasma membrane, vacuoles, peroxisomes and mitochondria. Most of them have initially been discovered through their ability to confer resistance to a multitude of drugs, a phenomenon called PDR (pleiotropic drug resistance) or MDR (multidrug resistance). Studying the mechanisms underlying PDR/MDR in yeast is of importance in two ways: first, ABC proteins can confer drug resistance on pathogenic fungi such as Candida spp., Aspergillus spp. or Cryptococcus neoformans; secondly, the well-established genetic, biochemical and cell biological tractability of Saccharomyces cerevisiae makes it an ideal tool to study basic mechanisms of drug transport by ABC proteins. In the past, knowledge from yeast has complemented work on human ABC transporters involved in anticancer drug resistance or genetic diseases. Interestingly, increasing evidence available from yeast and other organisms suggests that ABC proteins play a physiological role in membrane homoeostasis and lipid distribution, although this is being intensely debated in the literature.
Collapse
|
22
|
Comparative analysis of putative pathogenesis-related gene expression in two Rhizoctonia solani pathosystems. Curr Genet 2011; 57:391-408. [DOI: 10.1007/s00294-011-0353-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/05/2011] [Accepted: 08/15/2011] [Indexed: 10/17/2022]
|
23
|
Christians JK, Cheema MS, Vergara IA, Watt CA, Pinto LJ, Chen N, Moore MM. Quantitative trait locus (QTL) mapping reveals a role for unstudied genes in Aspergillus virulence. PLoS One 2011; 6:e19325. [PMID: 21559404 PMCID: PMC3084825 DOI: 10.1371/journal.pone.0019325] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 03/25/2011] [Indexed: 12/17/2022] Open
Abstract
Infections caused by the fungus Aspergillus are a major cause of morbidity and mortality in immunocompromised populations. To identify genes required for virulence that could be used as targets for novel treatments, we mapped quantitative trait loci (QTL) affecting virulence in the progeny of a cross between two strains of A. nidulans (FGSC strains A4 and A91). We genotyped 61 progeny at 739 single nucleotide polymorphisms (SNP) spread throughout the genome, and constructed a linkage map that was largely consistent with the genomic sequence, with the exception of one potential inversion of ∼527 kb on Chromosome V. The estimated genome size was 3705 cM and the average intermarker spacing was 5.0 cM. The average ratio of physical distance to genetic distance was 8.1 kb/cM, which is similar to previous estimates, and variation in recombination rate was significantly positively correlated with GC content, a pattern seen in other taxa. To map QTL affecting virulence, we measured the ability of each progeny strain to kill model hosts, larvae of the wax moth Galleria mellonella. We detected three QTL affecting in vivo virulence that were distinct from QTL affecting in vitro growth, and mapped the virulence QTL to regions containing 7-24 genes, excluding genes with no sequence variation between the parental strains and genes with only synonymous SNPs. None of the genes in our QTL target regions have been previously associated with virulence in Aspergillus, and almost half of these genes are currently annotated as "hypothetical". This study is the first to map QTL affecting the virulence of a fungal pathogen in an animal host, and our results illustrate the power of this approach to identify a short list of unknown genes for further investigation.
Collapse
Affiliation(s)
- Julian K Christians
- Department of Biological Sciences and Simon Fraser University, Burnaby, British Columbia, Canada.
| | | | | | | | | | | | | |
Collapse
|
24
|
Goulart L, Rosa e Silva LK, Chiapello L, Silveira C, Crestani J, Masih D, Vainstein MH. Cryptococcus neoformans and Cryptococcus gattii genes preferentially expressed during rat macrophage infection. Med Mycol 2011; 48:932-41. [PMID: 20302549 DOI: 10.3109/13693781003677494] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii are encapsulated yeast agents of cryptococcosis and facultative intracellular pathogens. The interaction of these yeasts with macrophages is essential for containing the infection. However, Cryptococcus spp. overcome this initial host defense barrier using a unique pathogenic strategy involving intracellular replication and cytoplasmic accumulation of polysaccharide-containing vesicles. Here, we employed representational difference analysis (RDA) to identify C. neoformans and C. gattii genes differentially expressed during intracellular growth in rat peritoneal macrophages. The upregulated transcripts of C. neoformans during macrophage interaction were related to ATP-binding cassette (ABC) transporters, intra-golgi transport, chaperone activity, ribosomal maintenance, NAD metabolism, histone methylation, stress response, and monosaccharide metabolism. In contrast, with C. gattii, upregulated genes were associated with cell growth, aerobic respiration, protein binding, microtubule nucleation, monosaccharides and nitrogen metabolism, inositol or phosphatidylinositol phosphatase activity, cellular signaling, and stress response. Our findings reveal new genes that may be necessary for the intracellular parasitism of C. neoformans and C. gattii.
Collapse
Affiliation(s)
- Letícia Goulart
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | | | | | | | | | | |
Collapse
|
25
|
Kouidhi B, Ben Gaied M, Mhadhebi L, Bakhrouf A, Bouraoui A. Les pompes à efflux en mycologie médicale : mécanismes moléculaires et perspectives thérapeutiques. J Mycol Med 2010. [DOI: 10.1016/j.mycmed.2010.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
26
|
Endosomal and AP-3-dependent vacuolar trafficking routes make additive contributions to Candida albicans hyphal growth and pathogenesis. EUKARYOTIC CELL 2010; 9:1755-65. [PMID: 20870878 DOI: 10.1128/ec.00029-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans mutants deficient in vacuolar biogenesis are defective in polarized hyphal growth and virulence. However, the specific vacuolar trafficking routes required for hyphal growth and virulence are unknown. In Saccharomyces cerevisiae, two trafficking routes deliver material from the Golgi apparatus to the vacuole. One occurs via the late endosome and is dependent upon Vps21p, while the second bypasses the endosome and requires the AP-3 complex, including Aps3p. To determine the significance of these pathways in C. albicans hyphal growth and virulence, aps3Δ/Δ, vps21Δ/Δ, and aps3Δ/Δ vps21Δ/Δ mutant strains were constructed. Analysis of vacuolar morphology and localization of the vacuolar protein Mlt1p suggests that C. albicans Aps3p and Vps21p mediate two distinct transport pathways. The vps21Δ/Δ mutant has a minor reduction in hyphal elongation, while the aps3Δ/Δ mutant has no defect in hyphal growth. Interestingly, the aps3Δ/Δ vps21Δ/Δ double mutant has dramatically reduced hyphal growth. Overexpression of the Ume6p transcriptional activator resulted in constitutive hyphal growth of wild-type, aps3Δ/Δ, and vps21Δ/Δ strains and formation of highly vacuolated subapical compartments. Thus, Ume6p-dependent transcriptional responses are sufficient to induce subapical vacuolation. However, the aps3Δ/Δ vps21Δ/Δ mutant formed mainly pseudohyphae that lacked vacuolated compartments. The aps3Δ/Δ strain was virulent in a mouse model of disseminated infection; the vps21Δ/Δ mutant failed to kill mice but persisted within kidney tissue, while the double mutant was avirulent and cleared from the kidneys. These results suggest that while the AP-3 pathway alone has little impact on hyphal growth or virulence, it is much more significant when endosomal trafficking is disrupted.
Collapse
|
27
|
Lettner T, Zeidler U, Gimona M, Hauser M, Breitenbach M, Bito A. Candida albicans AGE3, the ortholog of the S. cerevisiae ARF-GAP-encoding gene GCS1, is required for hyphal growth and drug resistance. PLoS One 2010; 5:e11993. [PMID: 20700541 PMCID: PMC2916835 DOI: 10.1371/journal.pone.0011993] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 07/12/2010] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Hyphal growth and multidrug resistance of C. albicans are important features for virulence and antifungal therapy of this pathogenic fungus. METHODOLOGY/PRINCIPAL FINDINGS Here we show by phenotypic complementation analysis that the C. albicans gene AGE3 is the functional ortholog of the yeast ARF-GAP-encoding gene GCS1. The finding that the gene is required for efficient endocytosis points to an important functional role of Age3p in endosomal compartments. Most C. albicans age3Delta mutant cells which grew as cell clusters under yeast growth conditions showed defects in filamentation under different hyphal growth conditions and were almost completely disabled for invasive filamentous growth. Under hyphal growth conditions only a fraction of age3Delta cells shows a wild-type-like polarization pattern of the actin cytoskeleton and lipid rafts. Moreover, age3Delta cells were highly susceptible to several unrelated toxic compounds including antifungal azole drugs. Irrespective of the AGE3 genotype, C-terminal fusions of GFP to the drug efflux pumps Cdr1p and Mdr1p were predominantly localized in the plasma membrane. Moreover, the plasma membranes of wild-type and age3Delta mutant cells contained similar amounts of Cdr1p, Cdr2p and Mdr1p. CONCLUSIONS/SIGNIFICANCE The results indicate that the defect in sustaining filament elongation is probably caused by the failure of age3Delta cells to polarize the actin cytoskeleton and possibly of inefficient endocytosis. The high susceptibility of age3Delta cells to azoles is not caused by inefficient transport of efflux pumps to the cell membrane. A possible role of a vacuolar defect of age3Delta cells in drug susceptibility is proposed and discussed. In conclusion, our study shows that the ARF-GAP Age3p is required for hyphal growth which is an important virulence factor of C. albicans and essential for detoxification of azole drugs which are routinely used for antifungal therapy. Thus, it represents a promising antifungal drug target.
Collapse
Affiliation(s)
- Thomas Lettner
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Ute Zeidler
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Mario Gimona
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Michael Hauser
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | | | - Arnold Bito
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| |
Collapse
|
28
|
Kovalchuk A, Driessen AJM. Phylogenetic analysis of fungal ABC transporters. BMC Genomics 2010; 11:177. [PMID: 20233411 PMCID: PMC2848647 DOI: 10.1186/1471-2164-11-177] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 03/16/2010] [Indexed: 12/22/2022] Open
Abstract
Background The superfamily of ABC proteins is among the largest known in nature. Its members are mainly, but not exclusively, involved in the transport of a broad range of substrates across biological membranes. Many contribute to multidrug resistance in microbial pathogens and cancer cells. The diversity of ABC proteins in fungi is comparable with those in multicellular animals, but so far fungal ABC proteins have barely been studied. Results We performed a phylogenetic analysis of the ABC proteins extracted from the genomes of 27 fungal species from 18 orders representing 5 fungal phyla thereby covering the most important groups. Our analysis demonstrated that some of the subfamilies of ABC proteins remained highly conserved in fungi, while others have undergone a remarkable group-specific diversification. Members of the various fungal phyla also differed significantly in the number of ABC proteins found in their genomes, which is especially reduced in the yeast S. cerevisiae and S. pombe. Conclusions Data obtained during our analysis should contribute to a better understanding of the diversity of the fungal ABC proteins and provide important clues about their possible biological functions.
Collapse
Affiliation(s)
- Andriy Kovalchuk
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
| | | |
Collapse
|
29
|
González-Guerrero M, Benabdellah K, Valderas A, Azcón-Aguilar C, Ferrol N. GintABC1 encodes a putative ABC transporter of the MRP subfamily induced by Cu, Cd, and oxidative stress in Glomus intraradices. MYCORRHIZA 2010; 20:137-46. [PMID: 19711106 DOI: 10.1007/s00572-009-0273-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 08/09/2009] [Indexed: 05/07/2023]
Abstract
A full-length cDNA sequence putatively encoding an ATP-binding cassette (ABC) transporter (GintABC1) was isolated from the extraradical mycelia of the arbuscular mycorrhizal fungus Glomus intraradices. Bioinformatic analysis of the sequence indicated that GintABC1 encodes a 1513 amino acid polypeptide, containing two six-transmembrane clusters (TMD) intercalated with sequences characteristics of the nucleotide binding domains (NBD) and an extra N-terminus extension (TMD0). GintABC1 presents a predicted TMD0-(TMD-NBD)(2) topology, typical of the multidrug resistance-associated protein subfamily of ABC transporters. Gene expression analyses revealed no difference in the expression levels of GintABC1 in the extra- vs the intraradical mycelia. GintABC1 was up-regulated by Cd and Cu, but not by Zn, suggesting that this transporter might be involved in Cu and Cd detoxification. Paraquat, an oxidative agent, also induced the transcription of GintABC1. These data suggest that redox changes may be involved in the transcriptional regulation of GintABC1 by Cd and Cu.
Collapse
Affiliation(s)
- Manuel González-Guerrero
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, c/Profesor Albareda 1, 18008 Granada, Spain
| | | | | | | | | |
Collapse
|
30
|
Gliotoxin in Aspergillus fumigatus: an example that mycotoxins are potential virulence factors. Mycotoxin Res 2009; 25:123-31. [DOI: 10.1007/s12550-009-0020-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 07/09/2009] [Accepted: 07/13/2009] [Indexed: 11/26/2022]
|
31
|
Abstract
Pathogens must be able to overcome both host defenses and antimicrobial treatment in order to successfully infect and maintain colonization of the host. One way fungi accomplish this feat and overcome intercellular toxin accumulation is efflux pumps, in particular ATP-binding cassette transporters and transporters of the major facilitator superfamily. Members of these two superfamilies remove many toxic compounds by coupling transport with ATP hydrolysis or a proton gradient, respectively. Fungal genomes encode a plethora of members of these families of transporters compared to other organisms. In this review we discuss the role these two fungal superfamilies of transporters play in virulence and resistance to antifungal agents. These efflux transporters are responsible not only for export of compounds involved in pathogenesis such as secondary metabolites, but also export of host-derived antimicrobial compounds. In addition, we examine the current knowledge of these transporters in resistance of pathogens to clinically relevant antifungal agents.
Collapse
Affiliation(s)
- Jeffrey J. Coleman
- Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
32
|
Comparative genomics using microarrays reveals divergence and loss of virulence-associated genes in host-specific strains of the insect pathogen Metarhizium anisopliae. EUKARYOTIC CELL 2009; 8:888-98. [PMID: 19395664 DOI: 10.1128/ec.00058-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Many strains of Metarhizium anisopliae have broad host ranges, but others are specialists and adapted to particular hosts. Patterns of gene duplication, divergence, and deletion in three generalist and three specialist strains were investigated by heterologous hybridization of genomic DNA to genes from the generalist strain Ma2575. As expected, major life processes are highly conserved, presumably due to purifying selection. However, up to 7% of Ma2575 genes were highly divergent or absent in specialist strains. Many of these sequences are conserved in other fungal species, suggesting that there has been rapid evolution and loss in specialist Metarhizium genomes. Some poorly hybridizing genes in specialists were functionally coordinated, indicative of reductive evolution. These included several involved in toxin biosynthesis and sugar metabolism in root exudates, suggesting that specialists are losing genes required to live in alternative hosts or as saprophytes. Several components of mobile genetic elements were also highly divergent or lost in specialists. Exceptionally, the genome of the specialist cricket pathogen Ma443 contained extra insertion elements that might play a role in generating evolutionary novelty. This study throws light on the abundance of orphans in genomes, as 15% of orphan sequences were found to be rapidly evolving in the Ma2575 lineage.
Collapse
|
33
|
Veses V, Richards A, Gow NAR. Vacuoles and fungal biology. Curr Opin Microbiol 2008; 11:503-10. [DOI: 10.1016/j.mib.2008.09.017] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 09/19/2008] [Accepted: 09/22/2008] [Indexed: 10/21/2022]
|
34
|
Jackson BE, Wilhelmus KR, Mitchell BM. Genetically regulated filamentation contributes to Candida albicans virulence during corneal infection. Microb Pathog 2007; 42:88-93. [PMID: 17241762 PMCID: PMC1892154 DOI: 10.1016/j.micpath.2006.11.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 11/21/2006] [Accepted: 11/30/2006] [Indexed: 01/30/2023]
Abstract
Candida albicans is a commensal fungus of the normal flora yet causes opportunistic infection following trauma or surgery and during immunosuppression. C. albicans virulence factors include morphogenesis into invasive filaments, adherence to host cells, and secretion of proteases. This study evaluated the role of fungal hyphal extension in experimental C. albicans keratitis using genetically altered yeast strains. Scarified corneas of adult BALB/c mice were topically inoculated with wild-type (SC5314) or 10 transposon-induced mutant strains of C. albicans and monitored for 4 days post inoculation (PI). In vitro growth kinetics and the yeast strains' ability to bud into pseudohyphae or hyphae were also compared. The wild-type human isolate had a high degree of virulence in the murine cornea, and four fungal strains deficient in genes regulating adherence or encoding membrane proteins did not significantly differ from the parental strain (P>0.3). Five yeast strains deficient in genes involved in filamentation resulted in fully or partially attenuated keratomycosis (P<0.0001). The overall growth kinetics of wild-type and mutant strains were similar in rich media (P>0.9), but mutants with deficient morphogenesis had reduced filamentation in vitro. Phenotypic switching from yeasts to filamentous forms facilitates the establishment and progression of experimental corneal disease by C. albicans.
Collapse
Affiliation(s)
- Beth E. Jackson
- Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, Houston, TX 77030, USA
- *Corresponding author. Address: Sid W. Richardson Ocular Microbiology Laboratory, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, Houston, TX 77030, USA. Tel: +1 713 798 5952; fax: +1 713 798 4142. E-mail address: (B. Jackson)
| | - Kirk R. Wilhelmus
- Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, Houston, TX 77030, USA
| | - Bradley M. Mitchell
- Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, Houston, TX 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, 6565 Fannin Street, Houston, TX 77030, USA
| |
Collapse
|
35
|
Theiss S, Ishdorj G, Brenot A, Kretschmar M, Lan CY, Nichterlein T, Hacker J, Nigam S, Agabian N, Köhler GA. Inactivation of the phospholipase B gene PLB5 in wild-type Candida albicans reduces cell-associated phospholipase A2 activity and attenuates virulence. Int J Med Microbiol 2006; 296:405-20. [PMID: 16759910 PMCID: PMC2481510 DOI: 10.1016/j.ijmm.2006.03.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 03/15/2006] [Accepted: 03/15/2006] [Indexed: 11/24/2022] Open
Abstract
Phospholipases are critical for modification and redistribution of lipid substrates, membrane remodeling and microbial virulence. Among the many different classes of phospholipases, fungal phospholipase B (Plb) proteins show the broadest range of substrate specificity and hydrolytic activity, hydrolyzing acyl ester bonds in phospholipids and lysophospholipids and further catalyzing lysophospholipase-transacylase reactions. The genome of the opportunistic fungal pathogen Candida albicans encodes a PLB multigene family with five putative members; we present the first characterization of this group of potential virulence determinants. CaPLB5, the third member of this multigene family characterized herein is a putative secretory protein with a predicted GPI-anchor attachment site. Real-time RT-PCR gene expression analysis of CaPLB5 and the additional CaPLB gene family members revealed that filamentous growth and physiologically relevant environmental conditions are associated with increased PLB gene activity. The phenotypes expressed by null mutant and revertant strains of CaPLB5 indicate that this lipid hydrolase plays an important role for cell-associated phospholipase A(2) activity and in vivo organ colonization.
Collapse
Affiliation(s)
- Stephanie Theiss
- Zentrum für Infektionsforschung, Universität Würzburg, Würzburg, Germany
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
| | - Ganchimeg Ishdorj
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Universitäsklinikum Benjamin Franklin, Free University Berlin, Berlin, Germany
| | - Audrey Brenot
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | | | - Chung-Yu Lan
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Thomas Nichterlein
- Mikrobiologie und Hygiene, Klinikum der Stadt Mannheim, Mannheim, Germany
| | - Jörg Hacker
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Würzburg, Germany
| | - Santosh Nigam
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Universitäsklinikum Benjamin Franklin, Free University Berlin, Berlin, Germany
| | - Nina Agabian
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Gerwald A. Köhler
- Zentrum für Infektionsforschung, Universität Würzburg, Würzburg, Germany
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Corresponding author: Gerwald A. Köhler, Ph.D., Department of Biochemistry & Microbiology, Oklahoma State University, Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107-1898 U.S.A.. Phone: ++ 1 918 561 8302; Fax: ++ 1 918 561 5798; E-mail:
| |
Collapse
|
36
|
Sanguinetti M, Posteraro B, La Sorda M, Torelli R, Fiori B, Santangelo R, Delogu G, Fadda G. Role of AFR1, an ABC transporter-encoding gene, in the in vivo response to fluconazole and virulence of Cryptococcus neoformans. Infect Immun 2006; 74:1352-9. [PMID: 16428784 PMCID: PMC1360305 DOI: 10.1128/iai.74.2.1352-1359.2006] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have recently demonstrated that upregulation of the ATP binding cassette (ABC) transporter-encoding gene AFR1 in Cryptococcus neoformans is involved in the in vitro resistance to fluconazole of this yeast. In the present study, we investigated the role of AFR1 in the in vivo response to fluconazole in a mouse model of systemic cryptococcosis. Mice were infected with a wild-type fluconazole-susceptible strain of C. neoformans, strain BPY22; an afr1 mutant, BPY444, which displayed hypersusceptibility to fluconazole in vitro; or an AFR1-overexpressing strain, BPY445, which exhibited in vitro resistance to the drug. In each of the three groups, infected animals were randomly assigned to fluconazole treatment or untreated-control subgroups. As expected, fluconazole prolonged survival and reduced fungal tissue burdens (compared with no treatment) in BPY22- and BPY444-infected mice, whereas it had no significant effects in mice infected with BPY445. When the pathogenicities of these strains in mice were investigated, strain BPY445 was significantly more virulent than BPY22 following inhalational or intravenous inoculation, but mice infected with BPY444 survived significantly longer than BPY22-infected animals only when infection was acquired via the respiratory tract. In in vitro macrophage infection studies, strain BPY445 also displayed enhanced intracellular survival compared with strains BPY22 and BPY444, suggesting that its increased virulence may be due to its reduced vulnerability to the antimicrobial factors produced by phagocytic cells. These findings indicate that the upregulation of the AFR1 gene is an important factor in either determining the in vivo resistance to fluconazole or influencing the virulence of C. neoformans.
Collapse
Affiliation(s)
- Maurizio Sanguinetti
- Istituto di Microbiologia, Università Cattolica del Sacro Cuore, Largo F. Vito 1, Rome 00168, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Gaur M, Choudhury D, Prasad R. Complete inventory of ABC proteins in human pathogenic yeast, Candida albicans. J Mol Microbiol Biotechnol 2006; 9:3-15. [PMID: 16254441 DOI: 10.1159/000088141] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The recent completion of the sequencing project of the opportunistic human pathogenic yeast, Candida albicans (http://www.ncbi.nlm.nih.gov/), led us to analyze and classify its ATP-binding cassette (ABC) proteins, which constitute one of the largest superfamilies of proteins. Some of its members are multidrug transporters responsible for the commonly encountered problem of antifungal resistance. TBLASTN searches together with domain analysis identified 81 nucleotide-binding domains, which belong to 51 different putative open reading frames. Considering that each allelic pair represents a single ABC protein of the Candida genome, the total number of putative members of this superfamily is 28. Domain organization, sequence-based analysis and self-organizing map-based clustering led to the classification of Candida ABC proteins into 6 distinct subfamilies. Each subfamily from C. albicans has an equivalent in Saccharomyces cerevisiae suggesting a close evolutionary relationship between the two yeasts. Our searches also led to the identification of a new motif to each subfamily in Candida that could be used to identify sequences from the corresponding subfamily in other organisms. It is hoped that the inventory of Candida ABC transporters thus created will provide new insights into the role of ABC proteins in antifungal resistance as well as help in the functional characterization of the superfamily of these proteins.
Collapse
Affiliation(s)
- Manisha Gaur
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | | |
Collapse
|
38
|
Palmer GE, Kelly MN, Sturtevant JE. The Candida albicans vacuole is required for differentiation and efficient macrophage killing. EUKARYOTIC CELL 2005; 4:1677-86. [PMID: 16215175 PMCID: PMC1265890 DOI: 10.1128/ec.4.10.1677-1686.2005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Yeast-hypha differentiation is believed to be necessary for the normal progression of Candida albicans infections. The emergence and extension of a germ tube from a parental yeast cell are accompanied by dynamic changes in vacuole size and morphology. Although vacuolar function is required during this process, it is unclear if it is vacuolar expansion or some other vacuolar function that is important. We previously described a C. albicans vps11Delta mutant which lacked a recognizable vacuole compartment and with defects in multiple vacuolar functions. These include sensitivities to stress, reduced proteolytic activities, and severe defects in filamentation. Herein we utilize a partially functional VPS11 allele (vps11hr) to help define which vacuolar functions are required for differentiation and which influence interaction with macrophages. Mutant strains harboring this allele are not osmotically or temperature sensitive and have normal levels of secreted aspartyl protease and carboxypeptidase Y activity but have a fragmented vacuole morphology. Moreover, this mutant is defective in filamentation, suggesting that the major role the vacuole plays in yeast-hypha differentiation may relate directly to its morphology. The results of this study support the hypothesis that vacuole expansion is required during germ tube emergence. Both vps11 mutants were severely attenuated in their ability to kill a macrophage cell line. The viability of the vps11delta mutant was significantly reduced during macrophage interaction compared to that in the control strains, while the vps11hr mutant was unaffected. This implies some vacuolar functions are required for Candida survival within the macrophage, while additional vacuolar functions are required to inflict injury on the macrophage.
Collapse
Affiliation(s)
- G E Palmer
- Department of MIP, Louisianna State University Health Sciences Center School of Dentistry, 1100 Florida Ave., Box F8-130, New Orleans, Louisianna 70119, USA.
| | | | | |
Collapse
|
39
|
Lee SA, Khalique Z, Gale CA, Wong B. Intracellular trafficking of fluorescently tagged proteins associated with pathogenesis in Candida albicans. Med Mycol 2005; 43:423-30. [PMID: 16178371 DOI: 10.1080/13693780400013340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Proteins that enter the secretory pathway play important roles in virulence and pathogenesis in Candida albicans, but our understanding of the trafficking of these proteins is in its early stages. In Saccharomyces cerevisiae, dominant negative alleles of YPT1 and SEC4 interrupt secretory traffic at pre- and post-Golgi steps, respectively. We therefore used a dominant negative genetic approach to examine the intracellular trafficking of several proteins associated with virulence or azole resistance. When the dominant negative ypt1(N121I) allele of C. albicans was overexpressed, yellow-fluorescent protein (YFP) tagged forms of two plasma membrane transporters (Cdrlp and Ftrlp) and the vacuolar membrane ABC transporter Mltlp accumulated in intracellular structures that appeared related to the ER, but localization of Cdc10p and Int1p was unaffected. When the dominant negative sec4(S28N) allele of C. albicans was overexpressed, Cdrlp and Ftrlp accumulated intracellularly, and localization of Mltlp, Cdc10p and Int1p was unaffected. These results imply that (i) Cdrlp and Ftrlp are transported to the plasma membrane by the general secretory pathway, (ii) Mlt1p enters the secretory pathway but is diverted to the vacuole at an early post-Golgi step, and (iii) like Cdc10p, Int1p does not enter the general secretory pathway.
Collapse
Affiliation(s)
- Samuel A Lee
- Infectious Diseases Section, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | | |
Collapse
|
40
|
Poltermann S, Nguyen M, Günther J, Wendland J, Härtl A, Künkel W, Zipfel PF, Eck R. The putative vacuolar ATPase subunit Vma7p of Candida albicans is involved in vacuole acidification, hyphal development and virulence. MICROBIOLOGY-SGM 2005; 151:1645-1655. [PMID: 15870472 DOI: 10.1099/mic.0.27505-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The vacuolar H+-ATPase (V-ATPase) component Vma7p of the human-pathogenic yeast Candida albicans regulates hyphal growth induced by serum and Spider medium and is essential for virulence. In order to characterize the functions of the putative V-ATPase subunit Vma7p of C. albicans, null mutants were generated. The resulting mutants showed reduced vacuole acidification, which correlated with defective growth at alkaline pH. In addition, defects in degradation of intravacuolar putative endosomal structures were observed. vma7 null mutants were sensitive towards the presence of metal ions. It is concluded that the sequestration of toxic ions in the vacuole via a H+ gradient generated by the V-ATPase is affected. The vma7 null mutant strains were avirulent in a mouse model of systemic candidiasis. In addition, C. albicans vma7 null mutants and the null mutant strain of the Vma7p-interacting phosphatidylinositol 3-kinase Vps34p showed similar phenotypes. In summary, the V-ATPase subunit Vma7p is involved in vacuolar ion transport and this transport is required for hyphal growth and virulence of C. albicans.
Collapse
Affiliation(s)
- Sophia Poltermann
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Monika Nguyen
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Juliane Günther
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Jürgen Wendland
- Friedrich Schiller University, Department of Microbiology, D-07745 Jena, Germany
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Albert Härtl
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Waldemar Künkel
- University of Applied Sciences, Tatzendpromenade 1b, D-07745 Jena, Germany
| | - Peter F Zipfel
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Raimund Eck
- Leibniz Institute for Natural Products Research and Infection Biology/Hans Knöll Institute, Department of Infection Biology, Beutenbergstrasse 11, D-07745 Jena, Germany
| |
Collapse
|
41
|
Braun BR, van het Hoog M, d'Enfert C, Martchenko M, Dungan J, Kuo A, Inglis DO, Uhl MA, Hogues H, Berriman M, Lorenz M, Levitin A, Oberholzer U, Bachewich C, Harcus D, Marcil A, Dignard D, Iouk T, Zito R, Frangeul L, Tekaia F, Rutherford K, Wang E, Munro CA, Bates S, Gow NA, Hoyer LL, Köhler G, Morschhäuser J, Newport G, Znaidi S, Raymond M, Turcotte B, Sherlock G, Costanzo M, Ihmels J, Berman J, Sanglard D, Agabian N, Mitchell AP, Johnson AD, Whiteway M, Nantel A. A human-curated annotation of the Candida albicans genome. PLoS Genet 2005; 1:36-57. [PMID: 16103911 PMCID: PMC1183520 DOI: 10.1371/journal.pgen.0010001] [Citation(s) in RCA: 252] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 03/14/2005] [Indexed: 11/24/2022] Open
Abstract
Recent sequencing and assembly of the genome for the fungal pathogen Candida albicans used simple automated procedures for the identification of putative genes. We have reviewed the entire assembly, both by hand and with additional bioinformatic resources, to accurately map and describe 6,354 genes and to identify 246 genes whose original database entries contained sequencing errors (or possibly mutations) that affect their reading frame. Comparison with other fungal genomes permitted the identification of numerous fungus-specific genes that might be targeted for antifungal therapy. We also observed that, compared to other fungi, the protein-coding sequences in the C. albicans genome are especially rich in short sequence repeats. Finally, our improved annotation permitted a detailed analysis of several multigene families, and comparative genomic studies showed that C. albicans has a far greater catabolic range, encoding respiratory Complex 1, several novel oxidoreductases and ketone body degrading enzymes, malonyl-CoA and enoyl-CoA carriers, several novel amino acid degrading enzymes, a variety of secreted catabolic lipases and proteases, and numerous transporters to assimilate the resulting nutrients. The results of these efforts will ensure that the Candida research community has uniform and comprehensive genomic information for medical research as well as for future diagnostic and therapeutic applications.
Collapse
Affiliation(s)
- Burkhard R Braun
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Marco van het Hoog
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Christophe d'Enfert
- Unité Postulante Biologie et Pathogénicité Fongiques, INRA USC 2019, Institut Pasteur, Paris, France
| | - Mikhail Martchenko
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Jan Dungan
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Alan Kuo
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Diane O Inglis
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - M. Andrew Uhl
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Hervé Hogues
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | | | - Michael Lorenz
- Department of Microbiology and Molecular Genetics, Utah-Houston Medical School, Houston, Texas, United States of America
| | - Anastasia Levitin
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Ursula Oberholzer
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Catherine Bachewich
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Doreen Harcus
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Anne Marcil
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Daniel Dignard
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Tatiana Iouk
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Rosa Zito
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Lionel Frangeul
- Plate-Forme Intégration et Analyse Génomique, Institut Pasteur, Paris, France
| | - Fredj Tekaia
- Unité de Génétique Moléculaire des Levures, Institut Pasteur, Paris, France
| | | | - Edwin Wang
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Carol A Munro
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Steve Bates
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Neil A Gow
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Lois L Hoyer
- Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Gerwald Köhler
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Joachim Morschhäuser
- Institut für Molekulare Infektionsbiologie, Universität Wurzburg, Wurzburg, Germany
| | - George Newport
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Sadri Znaidi
- Institut de Recherches Cliniques de Montreal, Montreal, Quebec, Canada
| | - Martine Raymond
- Institut de Recherches Cliniques de Montreal, Montreal, Quebec, Canada
| | - Bernard Turcotte
- Department of Medicine, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada
| | - Gavin Sherlock
- Department of Genetics, Stanford University School of Medicine, Palo Alto, California, United States of America
| | - Maria Costanzo
- Department of Genetics, Stanford University School of Medicine, Palo Alto, California, United States of America
| | - Jan Ihmels
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Judith Berman
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dominique Sanglard
- Institute of Microbiology, University Hospital Lausanne, Lausanne, Switzerland
| | - Nina Agabian
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Aaron P Mitchell
- Department of Microbiology and Institute of Cancer Research, Columbia University, New York, New York, United States of America
| | - Alexander D Johnson
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Malcolm Whiteway
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - André Nantel
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| |
Collapse
|
42
|
Keon J, Antoniw J, Rudd J, Skinner W, Hargreaves J, Hammond-Kosack K. Analysis of expressed sequence tags from the wheat leaf blotch pathogen Mycosphaerella graminicola (anamorph Septoria tritici). Fungal Genet Biol 2005; 42:376-89. [PMID: 15809003 DOI: 10.1016/j.fgb.2004.12.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 12/20/2004] [Accepted: 12/29/2004] [Indexed: 10/25/2022]
Abstract
Mycosphaerella graminicola is a major fungal pathogen of wheat as the causal agent of Septoria leaf blotch disease. As a first step toward a greater understanding of the mechanism of host infection we have generated, sequenced, and analyzed three M. graminicola EST libraries from conditions predicted to resemble independent phases of the host infection process, including one library generated from the fungus during interaction with its host. A total of 5180 ESTs were sequenced and clustered into 886 contigs and 2039 singletons to give a set of 2925 unique sequences (unisequences). BLASTX analysis revealed 33% of the unknown M. graminicola unisequences to be orphans. Very limited inter-library overlap of expression was seen with the majority of unisequences (contigs and singletons) being library-specific. Analysis of EST redundancy between libraries demonstrated a significant difference in gene expression in the three conditions. Comparisons made against fully sequenced genomes revealed most M. graminicola sequences to be homologous to genes present in both pathogenic and non-pathogenic Ascomycete filamentous fungi. A range of sequences having significant homology to verified pathogenicity/virulence genes (HvPV-genes) of either plant or mammalian fungal and Oomycete pathogens were also identified (<1e-20). The generation of, and the diversity present within, this EST collection will facilitate future efforts aimed at a more detailed study of the transcriptome of the fungus during host infection.
Collapse
Affiliation(s)
- John Keon
- Wheat Pathogenesis Programme, Plant-Pathogen Interactions Division, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
| | | | | | | | | | | |
Collapse
|
43
|
Veses V, Casanova M, Murgui A, Domínguez A, Gow NAR, Martínez JP. ABG1, a novel and essential Candida albicans gene encoding a vacuolar protein involved in cytokinesis and hyphal branching. EUKARYOTIC CELL 2005; 4:1088-101. [PMID: 15947201 PMCID: PMC1151987 DOI: 10.1128/ec.4.6.1088-1101.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Accepted: 04/19/2005] [Indexed: 11/20/2022]
Abstract
Immunoscreening of a Candida albicans expression library resulted in the isolation of a novel gene encoding a 32.9-kDa polypeptide (288 amino acids), with 27.7% homology to the product of Saccharomyces cerevisiae YGR106c, a putative vacuolar protein. Heterozygous mutants in this gene displayed an altered budding growth pattern, characterized by the formation of chains of buds, decreasingly in size towards the apex, without separation of the daughter buds. Consequently, this gene was designated ABG1. A conditional mutant for ABG1 with the remaining allele under the control of the MET3 promoter did not grow in the presence of methionine and cysteine, demonstrating that ABG1 was essential for viability. Western analysis revealed the presence of a major 32.9-kDa band, mainly in a particulate fraction (P40) enriched in vacuoles, and tagging with green fluorescent protein confirmed that Abg1p localized to the vacuole. Vacuole inheritance has been linked to the regulation of branching frequency in C. albicans. Under repressing conditions, the conditional mutant had an increased frequency of branching under hyphal inducing conditions and an altered sensitivity to substances that interfered with cell wall assembly. Repression of ABG1 in the conditional mutant strain caused disturbance of normal size and number of vacuoles both in yeast and mycelial cells and also in the asymmetric vacuole inheritance associated with the characteristic pattern of germ tubes and branching in C. albicans. These observations indicate that ABG1 plays a key role in vacuole biogenesis, cytokinesis, and hyphal branching.
Collapse
Affiliation(s)
- Verónica Veses
- Departamento de Microbiología y Ecologí, Facultad de Farmacia, Universitat de València, 46100-Burjasot, Valencia, Spain
| | | | | | | | | | | |
Collapse
|
44
|
Abstract
Glutathione (GSH; gamma-L-glutamyl-L-cysteinyl-glycine), a non-protein thiol with a very low redox potential (E'0 = 240 mV for thiol-disulfide exchange), is present in high concentration up to 10 mM in yeasts and filamentous fungi. GSH is concerned with basic cellular functions as well as the maintenance of mitochondrial structure, membrane integrity, and in cell differentiation and development. GSH plays key roles in the response to several stress situations in fungi. For example, GSH is an important antioxidant molecule, which reacts non-enzymatically with a series of reactive oxygen species. In addition, the response to oxidative stress also involves GSH biosynthesis enzymes, NADPH-dependent GSH-regenerating reductase, glutathione S-transferase along with peroxide-eliminating glutathione peroxidase and glutaredoxins. Some components of the GSH-dependent antioxidative defence system confer resistance against heat shock and osmotic stress. Formation of protein-SSG mixed disulfides results in protection against desiccation-induced oxidative injuries in lichens. Intracellular GSH and GSH-derived phytochelatins hinder the progression of heavy metal-initiated cell injuries by chelating and sequestering the metal ions themselves and/or by eliminating reactive oxygen species. In fungi, GSH is mobilized to ensure cellular maintenance under sulfur or nitrogen starvation. Moreover, adaptation to carbon deprivation stress results in an increased tolerance to oxidative stress, which involves the induction of GSH-dependent elements of the antioxidant defence system. GSH-dependent detoxification processes concern the elimination of toxic endogenous metabolites, such as excess formaldehyde produced during the growth of the methylotrophic yeasts, by formaldehyde dehydrogenase and methylglyoxal, a by-product of glycolysis, by the glyoxalase pathway. Detoxification of xenobiotics, such as halogenated aromatic and alkylating agents, relies on glutathione S-transferases. In yeast, these enzymes may participate in the elimination of toxic intermediates that accumulate in stationary phase and/or act in a similar fashion as heat shock proteins. GSH S-conjugates may also form in a glutathione S-transferases-independent way, e.g. through chemical reaction between GSH and the antifugal agent Thiram. GSH-dependent detoxification of penicillin side-chain precursors was shown in Penicillium sp. GSH controls aging and autolysis in several fungal species, and possesses an anti-apoptotic feature.
Collapse
Affiliation(s)
- István Pócsi
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, P.O. Box 63, H-4010 Debrecen, Hungary
| | | | | |
Collapse
|
45
|
Gray CH, Ines Borges-Walmsley M, Evans GJ, Walmsley AR. The pfr1 gene from the human pathogenic fungus Paracoccidioides brasiliensis encodes a half-ABC transporter that is transcribed in response to treatment with fluconazole. Yeast 2003; 20:865-80. [PMID: 12868056 DOI: 10.1002/yea.1013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have isolated a gene that encodes a half-ABC-transporter, designated Pfr1, from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis, which has high identity with members of the ABC-superfamily involved in multidrug resistance. The pfr1 gene is predicted to encode a 827 amino acid protein that, in common with mammalian Mdr1, has a TM-NBD topology. The transcription of the pfr1 gene is induced by the triazole drug fluconazole but not by amphotericin B, suggesting a role in transport-mediated azole resistance. However, Pfr1 has greatest identity to the mitochondrial ABC transporters Mdl1 and Mdl2 from Saccharomyces cerevisiae and mammalian ABC-me, with identities of 47.2%, 40.6% and 39.5%, respectively, over the length of these proteins. Furthermore, the N-terminus of Pfr1 is rich in positively charged residues, a feature of mitochondrial targeting sequences. Considering these features, it seems likely that Pfr1 is a mitochondrial protein. Previous studies have revealed that the acquisition of azole resistance in S. cerevisiae is linked to mitochondrial loss and, conversely, that mitochondrial dysfunction can lead to the upregulation of PDR transporters mediated by the transcription factor Pdr3. Our studies suggest that a mitochondrial ABC transporter is induced as part of the cellular response to drug treatment. The promoter region of pfr1 contains a PDRE-like consensus sequence to which Pdr3 binds, which may be the element responsible for the upregulation of Pfr1 in response to fluconazole. The nucleotide binding domain of Pfr1 was expressed and purified from Escherichia coli and shown to retain ATPase activity, consistent with Pfr1 functioning as a homodimeric transport ATPase.
Collapse
MESH Headings
- ATP-Binding Cassette Transporters/biosynthesis
- ATP-Binding Cassette Transporters/genetics
- Adenosine Triphosphatases/metabolism
- Amino Acid Sequence
- Antifungal Agents/pharmacology
- Base Sequence
- Cloning, Molecular
- Drug Resistance, Fungal
- Fluconazole/pharmacology
- Fungal Proteins/biosynthesis
- Fungal Proteins/genetics
- Genes, Fungal/drug effects
- Genes, Fungal/genetics
- Genes, Fungal/physiology
- Humans
- Mitochondria/genetics
- Mitochondria/metabolism
- Molecular Sequence Data
- Paracoccidioides/drug effects
- Paracoccidioides/genetics
- Paracoccidioides/metabolism
- Phylogeny
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Alignment
- Sequence Analysis, DNA
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- Transcription, Genetic/physiology
- Up-Regulation/drug effects
Collapse
Affiliation(s)
- Christopher H Gray
- Centre for Infectious Diseases, Wolfson Research Institute, University of Durham, Queen's Campus, Stockton-on-Tees TS17 6BH, UK
| | | | | | | |
Collapse
|
46
|
Theiss S, Köhler GA, Kretschmar M, Nichterlein T, Hacker J. New molecular methods to study gene functions in Candida infections. Mycoses 2002; 45:345-50. [PMID: 12421279 DOI: 10.1046/j.1439-0507.2002.00792.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans has become a model system for human pathogenic fungi in clinical research, mainly due to the increasing number of Candida infections. Molecular techniques to study C. albicans virulence properties have been improved over the last few years, despite difficulties in genetic manipulation of this fungus. Some of the recent achievements from our own laboratory or from other groups are described in this article. The molecular analysis of the recently identified ATP-dependent transporter Mlt1 using the green fluorescent protein (GFP) as reporter for protein localization and the dominant MPAR gene as a selection marker for gene inactivation provides an example for the study of gene functions in C. albicans.
Collapse
Affiliation(s)
- S Theiss
- Zentrum für Infektionsforschung, Universität Würzburg, Germany
| | | | | | | | | |
Collapse
|
47
|
Current awareness on yeast. Yeast 2002; 19:805-12. [PMID: 12112235 DOI: 10.1002/yea.825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|