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Dong Y, Ma H, Sun L, He R, Ye X, Gan B, Zhang Q, Gong Z, Han X, Duan X, Yan J. Comparative Transcriptome Analysis of Candidate Genes Associated with Mycelia Growth from a He-Ne Laser with Pulsed Light Mutant of Phellinus igniarius (Agaricomycetes). Int J Med Mushrooms 2024; 26:71-85. [PMID: 38421697 DOI: 10.1615/intjmedmushrooms.2023051538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
A mutant Phellinus igniarius JQ9 with higher mycelial production was screened out by He-Ne laser with pulsed light irradiation, the mechanism underlying the higher mycelial production is still unknown. This study aims to obtain a comprehensive transcriptome assembly during the Ph. igniarius liquid fermentation and characterize the key genes associated with the mycelial growth and metabolism in Ph. igniarius JQ9. Our transcriptome data of Ph. iniarius JQ9 and the wild strain were obtained with the Illumina platform comparative transcriptome sequencing technology. The results showed that among all the 346 differentially expressed genes (DEGs), 245 were upregulated and 101 were downregulated. Candidate genes encoding endoglucanase, beta-glucosidase, cellulose 1,4-beta-cellobiosidase, glycoside hydrolase family 61 protein, were proposed to participate in the carbohydrate utilization from KEGG enrichment of the starch and sucrose metabolism pathways were upregulated in Ph. igniarius JQ9. In addition, three candidate genes encoding the laccase and another two candidate genes related with the cell growth were higher expressed in Ph. igniarius JQ9 than in the wild type of strain (CK). Analysis of these data revealed that increased these related carbohydrate metabolism candidate genes underlying one crucial way may cause the higher mycelia production.
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Affiliation(s)
- Yating Dong
- School of Food and Biological Engineering, Institute of Food Physical Processing, International Joint Research Center for Food Physical Processing, Jiangsu University, No. 301 Xuefu Road, Zhenjiang 212013, P.R. China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), 9 Hupan West Road, Tianfu New Area, Chengdu, 610000, P.R. China
| | - Haile Ma
- School of Food and Biological Engineering, Institute of food physical processing, Jiangsu University
| | - Ling Sun
- School of Food and Biological Engineering, Jiangsu University, No. 301 Xuefu Road, Zhenjiang 212013, P.R. China
| | - Ronghai He
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang Jiangsu 212013, China
| | - Xiaofei Ye
- School of Food and Biological Engineering, Jiangsu University, No. 301 Xuefu Road, Zhenjiang 212013, P.R. China; Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville 37996, Tennessee, USA
| | - Bingcheng Gan
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), 9 Hupan West Road, Tianfu New Area, Chengdu, 610000 P.R. China
| | - Qin Zhang
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), Tianfu New Area, Chengdu, 610000, P.R. China
| | - ZongJun Gong
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), Tianfu New Area, Chengdu, 610000, P.R. China
| | - Xing Han
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), 9 Hupan West Road, Tianfu New Area, Chengdu, 610000, P.R. China
| | - Xinlian Duan
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), Tianfu New Area, Chengdu, 610000, P.R. China
| | - Junjie Yan
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, National Agricultural Science & Technology Center (NASC), 9 Hupan West Road, Tianfu New Area, Chengdu, 610000, P.R. China
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Mochizuki S, Fukumoto T, Ohara T, Ohtani K, Yoshihara A, Shigematsu Y, Tanaka K, Ebihara K, Tajima S, Gomi K, Ichimura K, Izumori K, Akimitsu K. The rare sugar D-tagatose protects plants from downy mildews and is a safe fungicidal agrochemical. Commun Biol 2020; 3:423. [PMID: 32759958 PMCID: PMC7406649 DOI: 10.1038/s42003-020-01133-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 07/09/2020] [Indexed: 11/09/2022] Open
Abstract
The rare sugar D-tagatose is a safe natural product used as a commercial food ingredient. Here, we show that D-tagatose controls a wide range of plant diseases and focus on downy mildews to analyze its mode of action. It likely acts directly on the pathogen, rather than as a plant defense activator. Synthesis of mannan and related products of D-mannose metabolism are essential for development of fungi and oomycetes; D-tagatose inhibits the first step of mannose metabolism, the phosphorylation of D-fructose to D-fructose 6-phosphate by fructokinase, and also produces D-tagatose 6-phosphate. D-Tagatose 6-phosphate sequentially inhibits phosphomannose isomerase, causing a reduction in D-glucose 6-phosphate and D-fructose 6-phosphate, common substrates for glycolysis, and in D-mannose 6-phosphate, needed to synthesize mannan and related products. These chain-inhibitory effects on metabolic steps are significant enough to block initial infection and structural development needed for reproduction such as conidiophore and conidiospore formation of downy mildew.
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Affiliation(s)
- Susumu Mochizuki
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Takeshi Fukumoto
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
- Agrochemical Research Center, Mitsui Chemicals Agro, Inc., 1358 Ichimiyake, Yasu, Shiga, 520-2362, Japan
| | - Toshiaki Ohara
- Agrochemical Research Center, Mitsui Chemicals Agro, Inc., 1358 Ichimiyake, Yasu, Shiga, 520-2362, Japan
| | - Kouhei Ohtani
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Akihide Yoshihara
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Yoshio Shigematsu
- Agrochemical Research Center, Mitsui Chemicals Agro, Inc., 1358 Ichimiyake, Yasu, Shiga, 520-2362, Japan
| | - Keiji Tanaka
- Agrochemical Research Center, Mitsui Chemicals Agro, Inc., 1358 Ichimiyake, Yasu, Shiga, 520-2362, Japan
| | - Koichi Ebihara
- Agrochemical Research Center, Mitsui Chemicals Agro, Inc., 1358 Ichimiyake, Yasu, Shiga, 520-2362, Japan
| | - Shigeyuki Tajima
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Kenji Gomi
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Kazuya Ichimura
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Ken Izumori
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan
| | - Kazuya Akimitsu
- International Institute of Rare Sugar Research and Education & Faculty of Agriculture, Kagawa University, 2393, Miki, Kagawa, 761-0795, Japan.
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3
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Ahmad L, Plancqueel S, Dubosclard V, Lazar N, Ghattas W, Li de la Sierra‐Gallay I, Tilbeurgh H, Salmon L. Crystal structure of phosphomannose isomerase from
Candida albicans
complexed with 5‐phospho‐
d
‐arabinonhydrazide. FEBS Lett 2018; 592:1667-1680. [DOI: 10.1002/1873-3468.13059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/06/2018] [Accepted: 04/11/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Lama Ahmad
- Equipe de Chimie Bioorganique et Bioinorganique Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR8182 LabEx LERMIT Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Stéphane Plancqueel
- Institut de Biologie Intégrative de la Cellule (I2BC) CNRS UMR9198 Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Virginie Dubosclard
- Equipe de Chimie Bioorganique et Bioinorganique Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR8182 LabEx LERMIT Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Noureddine Lazar
- Institut de Biologie Intégrative de la Cellule (I2BC) CNRS UMR9198 Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Wadih Ghattas
- Equipe de Chimie Bioorganique et Bioinorganique Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR8182 LabEx LERMIT Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Inès Li de la Sierra‐Gallay
- Institut de Biologie Intégrative de la Cellule (I2BC) CNRS UMR9198 Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Herman Tilbeurgh
- Institut de Biologie Intégrative de la Cellule (I2BC) CNRS UMR9198 Université Paris‐Saclay Université Paris‐Sud Orsay France
| | - Laurent Salmon
- Equipe de Chimie Bioorganique et Bioinorganique Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR8182 LabEx LERMIT Université Paris‐Saclay Université Paris‐Sud Orsay France
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4
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Jeong HY, Chae KS, Whang SS. Presence of a mannoprotein, MnpAp, in the hyphal cell wall ofAspergillus nidulans. Mycologia 2017. [DOI: 10.1080/15572536.2005.11832996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Keon-Sang Chae
- Division of Biological Sciences, Chonbuk National University, Chonju, Chonbuk 561-756, Republic of Korea
| | - Sung Soo Whang
- Division of Science Education, Chonbuk National University, Chonju, Chonbuk 561-756, Republic of Korea
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Gresh N, Perahia D, de Courcy B, Foret J, Roux C, El-Khoury L, Piquemal JP, Salmon L. Complexes of a Zn-metalloenzyme binding site with hydroxamate-containing ligands. A case for detailed benchmarkings of polarizable molecular mechanics/dynamics potentials when the experimental binding structure is unknown. J Comput Chem 2016; 37:2770-2782. [DOI: 10.1002/jcc.24503] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 08/31/2016] [Accepted: 09/04/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Nohad Gresh
- Laboratoire de Chimie Théorique; Sorbonne Universités; UPMC, UMR 7616 CNRS Paris France
- Chemistry and Biology, Nucleo(s)tides and Immunology for Therapy (CBNIT); UMR 8601 CNRS, UFR Biomédicale; Paris France
| | - David Perahia
- Laboratoire de Biologie et Pharmacologie Appliquées (LBPA), UMR 8113; Ecole Normale Supérieure Cachan France
| | - Benoit de Courcy
- Laboratoire de Chimie Théorique; Sorbonne Universités; UPMC, UMR 7616 CNRS Paris France
- Chemistry and Biology, Nucleo(s)tides and Immunology for Therapy (CBNIT); UMR 8601 CNRS, UFR Biomédicale; Paris France
| | - Johanna Foret
- Laboratoire de Chimie Bioorganique et Bioinorganique; Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Univ Paris-Saclay, Univ Paris-Sud, UMR 8182 CNRS; rue du Doyen Georges Poitou Orsay F-91405 France
| | - Céline Roux
- Laboratoire de Chimie Bioorganique et Bioinorganique; Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Univ Paris-Saclay, Univ Paris-Sud, UMR 8182 CNRS; rue du Doyen Georges Poitou Orsay F-91405 France
| | - Lea El-Khoury
- Laboratoire de Chimie Théorique; Sorbonne Universités; UPMC, UMR 7616 CNRS Paris France
- Centre d'Analyses et de Recherche; UR EGFEM, LSIM, Faculté de Sciences, Saint Joseph University of Beirut; BP 11-514, Riad El Solh Beirut 1116-2050 Lebanon
| | - Jean-Philip Piquemal
- Laboratoire de Chimie Théorique; Sorbonne Universités; UPMC, UMR 7616 CNRS Paris France
- Department of Biomolecular Engineering; The University of Texas at Austin; Texas 78712
| | - Laurent Salmon
- Laboratoire de Chimie Bioorganique et Bioinorganique; Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Univ Paris-Saclay, Univ Paris-Sud, UMR 8182 CNRS; rue du Doyen Georges Poitou Orsay F-91405 France
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Walisko R, Moench-Tegeder J, Blotenberg J, Wucherpfennig T, Krull R. The Taming of the Shrew--Controlling the Morphology of Filamentous Eukaryotic and Prokaryotic Microorganisms. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 149:1-27. [PMID: 25796624 DOI: 10.1007/10_2015_322] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One of the most sensitive process characteristics in the cultivation of filamentous biological systems is their complex morphology. In submerged cultures, the observed macroscopic morphology of filamentous microorganisms varies from freely dispersed mycelium to dense spherical pellets consisting of a more or less dense, branched and partially intertwined network of hyphae. Recently, the freely dispersed mycelium form has been in high demand for submerged cultivation because this morphology enhances the growth and production of several valuable products. A distinct filamentous morphology and productivity are influenced by the environment and can be controlled by inoculum concentration, spore viability, pH value, cultivation temperature, dissolved oxygen concentration, medium composition, mechanical stress or process mode as well as through the addition of inorganic salts or microparticles, which provides the opportunity to tailor a filamentous morphology. The suitable morphology for a given bioprocess varies depending on the desired product. Therefore, the advantages and disadvantages of each morphological type should be carefully evaluated for every biological system. Because of the high industrial relevance of filamentous microorganisms, research in previous years has aimed at the development of tools and techniques to characterise their growth and obtain quantitative estimates of their morphological properties. The focus of this review is on current advances in the characterisation and control of filamentous morphology with a separation of eukaryotic and prokaryotic systems. Furthermore, recent strategies to tailor the morphology through classical biochemical process parameters, morphology and genetic engineering to optimise the productivity of these filamentous systems are discussed.
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Affiliation(s)
- Robert Walisko
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Gaußstraße 17, 38106, Braunschweig, Germany,
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7
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Pessoni RAB, Tersarotto CC, Mateus CAP, Zerlin JK, Simões K, de Cássia L Figueiredo-Ribeiro R, Braga MR. Fructose affecting morphology and inducing β-fructofuranosidases in Penicillium janczewskii. SPRINGERPLUS 2015; 4:487. [PMID: 26380163 PMCID: PMC4564379 DOI: 10.1186/s40064-015-1298-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 09/01/2015] [Indexed: 12/03/2022]
Abstract
Fructose, glucose, and an equimolar mixture of both sugars affected differently hyphae thickness, biomass production and secretion of β-fructofuranosidase in Penicillium janczewskii. Reduced growth, thinner hyphae and visible injuries were early observed during fungal cultivation in fructose-containing medium, reaching the maximum between 12 and 15 days of culture. Total sugar content from the cell wall was lower when fructose was supplied and polysaccharides lower than 10 kDa predominated, regardless the culture age. Maximal inulinase and invertase activities were detected in culture filtrates after 12 days, excepting in the glucose-containing medium. Structural changes in cell walls coincided with the increase of extracellular enzyme activity in the fructose-containing medium. The fragility of the hyphae might be related with both low carbohydrate content and predominance of low molecular weight glucans in the walls. Data presented here suggest changes in carbohydrate component of the cell walls are induced by the carbon source.
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Affiliation(s)
- Rosemeire A B Pessoni
- Faculdade da Saúde, Curso de Ciências Biológicas, Universidade Metodista de São Paulo, São Bernardo do Campo, SP Brazil
| | - Carla C Tersarotto
- Faculdade da Saúde, Curso de Ciências Biológicas, Universidade Metodista de São Paulo, São Bernardo do Campo, SP Brazil
| | - Cássia A P Mateus
- Faculdade da Saúde, Curso de Ciências Biológicas, Universidade Metodista de São Paulo, São Bernardo do Campo, SP Brazil
| | - Juliana K Zerlin
- Faculdade da Saúde, Curso de Ciências Biológicas, Universidade Metodista de São Paulo, São Bernardo do Campo, SP Brazil
| | - Kelly Simões
- Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica, CP 68041, São Paulo, SP CEP 04045-972 Brazil
| | | | - Márcia R Braga
- Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica, CP 68041, São Paulo, SP CEP 04045-972 Brazil
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8
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Hu P, Wang Y, Zhou J, Pan Y, Liu G. AcstuA, which encodes an APSES transcription regulator, is involved in conidiation, cephalosporin biosynthesis and cell wall integrity of Acremonium chrysogenum. Fungal Genet Biol 2015; 83:26-40. [PMID: 26283234 DOI: 10.1016/j.fgb.2015.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/21/2015] [Accepted: 08/13/2015] [Indexed: 01/02/2023]
Abstract
A transcriptional regulatory gene AcstuA was identified from Acremonium chrysogenum. AcstuA encodes a basic helix-loop-helix protein with similarity to StuA which regulates the core developmental processes of Aspergillus nidulans. Like disruption of stuA in A. nidulans, deficiency of AcstuA blocked the conidiation of A. chrysogenum through severely down-regulating the expression of AcbrlA and AcabaA which encode orthologs of the key fungal developmental regulators BrlA and AbaA. Disruption of AcstuA also drastically reduced cephalosporin production of A. chrysogenum. In agreement, the transcriptions of pcbAB, pbcC, cefD1, cefD2, cefEF and cefG were remarkably decreased in the AcstuA disruption mutant (ΔAcstuA). In addition to defects in conidiation and cephalosporin biosynthesis, ΔAcstuA produced abnormal swollen and fragmented hyphal cells during fermentation. The phenotypic alterations of hyphal cells caused by AcstuA deletion were restored by supplementation of NaCl in the medium, indicating that the deficiency of AcstuA has an influence on the cell wall integrity of A. chrysogenum. The transcriptions of two putative mannoprotein encoding genes Acmp2 and Acmp3 significantly reduced in ΔAcstuA, further indicating that cell wall integrity of the mutant is impaired. These results strongly suggested that AcstuA is involved in conidiation, cephalosporin production, hyphal fragmentation and cell wall integrity in A. chrysogenum.
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Affiliation(s)
- Pengjie Hu
- University of Science and Technology of China (USTC), Hefei 230026, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ying Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Zhou
- Technical Centre of Beijing Cigarette Factory, Beijing 101121, China
| | - Yuanyuan Pan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Gang Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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9
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Protein Glycosylation in Aspergillus fumigatus Is Essential for Cell Wall Synthesis and Serves as a Promising Model of Multicellular Eukaryotic Development. Int J Microbiol 2011; 2012:654251. [PMID: 21977037 PMCID: PMC3184424 DOI: 10.1155/2012/654251] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/19/2011] [Indexed: 02/05/2023] Open
Abstract
Glycosylation is a conserved posttranslational modification that is found in all eukaryotes, which helps generate proteins with multiple functions. Our knowledge of glycosylation mainly comes from the investigation of the yeast Saccharomyces cerevisiae and mammalian cells. However, during the last decade, glycosylation in the human pathogenic mold Aspergillus fumigatus has drawn significant attention. It has been revealed that glycosylation in A. fumigatus is crucial for its growth, cell wall synthesis, and development and that the process is more complicated than that found in the budding yeast S. cerevisiae. The present paper implies that the investigation of glycosylation in A. fumigatus is not only vital for elucidating the mechanism of fungal cell wall synthesis, which will benefit the design of new antifungal therapies, but also helps to understand the role of protein glycosylation in the development of multicellular eukaryotes. This paper describes the advances in functional analysis of protein glycosylation in A. fumigatus.
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10
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Cao Y, Li M, Xia Y. Mapmi gene contributes to stress tolerance and virulence of the entomopathogenic fungus, Metarhizium acridum. J Invertebr Pathol 2011; 108:7-12. [PMID: 21683706 DOI: 10.1016/j.jip.2011.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 05/26/2011] [Accepted: 06/02/2011] [Indexed: 02/01/2023]
Abstract
Phosphomannose isomerase (PMI) catalyzes the reversible interconversion of fructose 6-phosphate (Fru-6-P) and mannose 6-phosphate (Man-6-P), providing a link between glycolysis and the mannose metabolic pathway. In this study, we identified pmi gene (Mapmi) from the entomopathogenic fungus, Metarhizium acridum, and analyzed its functions using RNA interference (RNAi). Amending the growth medium with cell stress chemicals significantly reduced growth, conidial production and percent germination in Mapmi-RNAi mutant strain, compared to the wild-type strain. Growth of RNAi mutant was lower than the wild type strain with glucose or fructose as sole carbon source. RNAi mutant exhibited a normal growth phenotype with mannose at low concentrations, while trace or high concentration of mannose was more negatively impacted the growth of RNAi mutant than the wild type strain. Infection with Mapmi-RNAi mutant against Locusta migratoria manilensis (Meyen) led to a significantly reduced virulence compared to infection with the wild-type strain. These results suggest that Mapmi plays essential roles in stress tolerance and pathogenicity of M. acridum.
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Affiliation(s)
- Yueqing Cao
- Genetic Engineering Research Center, College of Bioengineering, Chongqing University, Chongqing Engineering Research Center for Fungal Insecticides and Key Lab. of Functional Gene and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing 400030, PR China
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11
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Roux C, Bhatt F, Foret J, de Courcy B, Gresh N, Piquemal JP, Jeffery CJ, Salmon L. The reaction mechanism of type I phosphomannose isomerases: new information from inhibition and polarizable molecular mechanics studies. Proteins 2011; 79:203-20. [PMID: 21058398 DOI: 10.1002/prot.22873] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Type I phosphomannose isomerases (PMIs) are zinc-dependent metalloenzymes involved in the reversible isomerization of D-mannose 6-phosphate (M6P) and D-fructose 6-phosphate (F6P). 5-Phospho-D-arabinonohydroxamic acid (5PAH), an inhibitor endowed with nanomolar affinity for yeast (Type I) and Pseudomonas aeruginosa (Type II) PMIs (Roux et al., Biochemistry 2004; 43:2926-2934), strongly inhibits human (Type I) PMI (for which we report an improved expression and purification procedure), as well as Escherichia coli (Type I) PMI. Its K(i) value of 41 nM for human PMI is the lowest value ever reported for an inhibitor of PMI. 5-Phospho-D-arabinonhydrazide, a neutral analogue of the reaction intermediate 1,2-cis-enediol, is about 15 times less efficient at inhibiting both enzymes, in accord with the anionic nature of the postulated high-energy reaction intermediate. Using the polarizable molecular mechanics, sum of interactions between fragments ab initio computed (SIBFA) procedure, computed structures of the complexes between Candida albicans (Type I) PMI and the cyclic substrate β-D-mannopyranose 6-phosphate (β-M6P) and between the enzyme and the high-energy intermediate analogue inhibitor 5PAH are reported. Their analysis allows us to identify clearly the nature of each individual active site amino acid and to formulate a hypothesis for the overall mechanism of the reaction catalyzed by Type I PMIs, that is, the ring-opening and isomerization steps, respectively. Following enzyme-catalyzed ring-opening of β-M6P by zinc-coordinated water and Gln111 ligands, Lys136 is identified as the probable catalytic base involved in proton transfer between the two carbon atoms C1 and C2 of the substrate D-mannose 6-phosphate.
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Affiliation(s)
- Céline Roux
- Laboratoire de Chimie Bioorganique et Bioinorganique, ICMMO, Univ Paris-Sud, UMR 8182, Orsay F-91405, France
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12
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Fang W, Yu X, Wang B, Zhou H, Ouyang H, Ming J, Jin C. Characterization of the Aspergillus fumigatus phosphomannose isomerase Pmi1 and its impact on cell wall synthesis and morphogenesis. Microbiology (Reading) 2009; 155:3281-3293. [DOI: 10.1099/mic.0.029975-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphomannose isomerase (PMI) is an enzyme catalysing the interconversion of mannose 6-phosphate (Man-6-P) and fructose 6-phosphate (Fru-6-P). The reaction catalysed by PMI is the first committed step in the synthesis of mannose-containing sugar chains and provides a link between glucose metabolism and mannosylation. In this study, the pmi1 gene was identified to encode PMI in the human fungal pathogen Aspergillus fumigatus. Characterization of A. fumigatus Pmi1 expressed in Escherichia coli revealed that this PMI mainly catalysed the conversion of Fru-6-P to Man-6-P and that its binding affinity for Man-6-P was similar to that of yeast PMIs, but different to those of PMIs from bacteria or animals. Loss of pmi1 was lethal unless Man was provided in the growth medium. However, a Δpmi1 mutant cell showed a significantly reduced growth rate at a high concentration of Man. Biochemical analysis revealed that both inadequate and replete Man led to an accumulation of intracellular Man-6-P and a reduction in the amount of α-glucan in the cell wall. Uncoupling of the link between energy production and glycosylation by deletion of the pmi1 gene led to phenotypes such as defects in cell wall integrity, abnormal morphology and reduced conidiation. Our results reveal that PMI activity is essential for viability and plays a central regulatory role in both cell wall synthesis and energy production in A. fumigatus.
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Affiliation(s)
- Wenxia Fang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Xiaoying Yu
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Bin Wang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Hui Zhou
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Haomiao Ouyang
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Jia Ming
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Cheng Jin
- Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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Synthesis and evaluation of non-hydrolyzable D-mannose 6-phosphate surrogates reveal 6-deoxy-6-dicarboxymethyl-D-mannose as a new strong inhibitor of phosphomannose isomerases. Bioorg Med Chem 2009; 17:7100-7. [PMID: 19783448 DOI: 10.1016/j.bmc.2009.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 08/28/2009] [Accepted: 09/03/2009] [Indexed: 11/23/2022]
Abstract
Non-hydrolyzable d-mannose 6-phosphate analogues in which the phosphate group was replaced by a phosphonomethyl, a dicarboxymethyl, or a carboxymethyl group were synthesized and kinetically evaluated as substrate analogues acting as potential inhibitors of type I phosphomannose isomerases (PMIs) from Saccharomyces cerevisiae and Escherichia coli. While 6-deoxy-6-phosphonomethyl-d-mannose and 6-deoxy-6-carboxymethyl-D-mannose did not inhibit the enzymes significantly, 6-deoxy-6-dicarboxymethyl-D-mannose appeared as a new strong competitive inhibitor of both S. cerevisiae and E. coli PMIs with K(m)/K(i) ratios of 28 and 8, respectively. We thus report the first malonate-based inhibitor of an aldose-ketose isomerase to date. Phosphonomethyl mimics of the 1,2-cis-enediolate high-energy intermediate postulated for the isomerization reaction catalyzed by PMIs were also synthesized but behave as poor inhibitors of PMIs. A polarizable molecular mechanics (SIBFA) study was performed on the complexes of d-mannose 6-phosphate and two of its analogues with PMI from Candida albicans, an enzyme involved in yeast infection homologous to S. cerevisiae and E. coli PMIs. It shows that effective binding to the catalytic site occurs with retention of the Zn(II)-bound water molecule. Thus the binding of the hydroxyl group on C1 of the ligand to Zn(II) should be water-mediated. The kinetic study reported here also suggests the dianionic character of the phosphate surrogate as a likely essential parameter for strong binding of the inhibitor to the enzyme active site.
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Jackson-Hayes L, Hill TW, Loprete DM, Fay LM, Gordon BS, Nkashama SA, Patel RK, Sartain CV. Two GDP-mannose transporters contribute to hyphal form and cell wall integrity in Aspergillus nidulans. MICROBIOLOGY-SGM 2008; 154:2037-2047. [PMID: 18599832 DOI: 10.1099/mic.0.2008/017483-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In order to identify novel genes affecting cell wall integrity, we have generated mutant strains of the filamentous fungus Aspergillus nidulans that show hypersensitivity to the chitin-binding agent Calcofluor White (CFW). Affected loci are designated cal loci. The phenotype of one of these alleles, calI11, also includes shortened hyphal compartments and increased density of branching in the absence of CFW, as well as reduced staining of cell walls by the lectin FITC-Concanavalin A (ConA), which has strong binding affinity for mannosyl residues. We have identified two A. nidulans genes (AN8848.3 and AN9298.3, designated gmtA and gmtB, respectively) that complement all aspects of the phenotype. Both genes show strong sequence similarity to GDP-mannose transporters (GMTs) of Saccharomyces and other yeasts. Sequencing of gmtA from the calI11 mutant strain reveals a G to C mutation at position 943, resulting in a predicted alanine to proline substitution at amino acid position 315 within a region that is highly conserved among other fungi. No mutations were observed in the mutant strain's allele of gmtB. Meiotic mapping demonstrated a recombination frequency of under 1 % between the calI locus and the phenA locus (located approximately 9.5 kb from AN8848.3), confirming that gmtA and calI are identical. A GmtA-GFP chimera exhibits a punctate distribution pattern, consistent with that shown by putative Golgi markers in A. nidulans. However, this distribution did not overlap with that of the putative Golgi equivalent marker CopA-monomeric red fluorescent protein (mRFP), which may indicate that the physically separated Golgi-equivalent organelles of A. nidulans represent physiologically distinct counterparts of the stacked cisternae of plants and animals. These findings demonstrate that gmtA and gmtB play roles in cell wall metabolism in A. nidulans similar to those previously reported for GMTs in yeasts.
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Affiliation(s)
| | - Terry W Hill
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
| | - Darlene M Loprete
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
| | - Lauren M Fay
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
| | - Barbara S Gordon
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
| | - Sonia A Nkashama
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
| | - Ravi K Patel
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
| | - Caroline V Sartain
- Departments of Chemistry and Biology, Rhodes College, Memphis, TN 38112, USA
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Down-regulation of Sclerotinia sclerotiorum gene expression in response to infection with Sclerotinia sclerotiorum debilitation-associated RNA virus. Virus Res 2008; 135:95-106. [PMID: 18384901 DOI: 10.1016/j.virusres.2008.02.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2007] [Revised: 02/23/2008] [Accepted: 02/23/2008] [Indexed: 12/24/2022]
Abstract
We have previously presented convincing evidence in support of a viral etiology for the debilitation phenotype exhibited by strain Ep-1PN of Sclerotinia sclerotiorum. To explore the possible mechanisms underlying fungal pathogenicity and hyphal growth, potential genes whose expression was down-regulated in Ep-1PN were identified from a cDNA library of the virus-free strain Ep-1PNAa, which is a single ascospore derivative of strain Ep-1PN, using reverse northern blot analysis. A total of 1116 cDNA clones were targeted and, following PCR re-amplification, 210 cDNA clones were selected as candidates, of which 16 cDNA clones were subjected to northern blot analysis for further confirmation. The results showed that 12 clones represented genes that were differentially expressed in the virus-free strain compared to the virus-infected one. Of the 210 clones that were sequenced, 150 had non-redundant sequences and of these 92% (138 clones) had significant homology to fungal genes in the databases examined. The remaining 12 clones did not have any matches. The differentially expressed genes represented a broad spectrum of biological functions including carbon and energy metabolism, protein synthesis and transport, signal transduction and stress response. This study provides the first insight into genes differentially expressed between the virus-free strain Ep-1PNAa and the virus-infected strain Ep-1PN. The possible relationships between mycovirus-mediated changes in cellular gene expression and observed phenotypes are discussed.
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Roux C, Gresh N, Perera LE, Piquemal JP, Salmon L. Binding of 5-phospho-D-arabinonohydroxamate and 5-phospho-D-arabinonate inhibitors to zinc phosphomannose isomerase from Candida albicans studied by polarizable molecular mechanics and quantum mechanics. J Comput Chem 2007; 28:938-57. [PMID: 17253648 DOI: 10.1002/jcc.20586] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Type I phosphomannose isomerase (PMI) is a Zn-dependent metalloenzyme involved in the isomerization of D-fructose 6-phosphate to D-mannose 6-phosphate. One of our laboratories has recently designed and synthesized 5-phospho-D-arabinonohydroxamate (5PAH), an inhibitor endowed with a nanomolar affinity for PMI (Roux et al., Biochemistry 2004, 43, 2926). By contrast, the 5-phospho-D-arabinonate (5PAA), in which the hydroxamate moiety is replaced by a carboxylate one, is devoid of inhibitory potency. Subsequent biochemical studies showed that in its PMI complex, 5PAH binds Zn(II) through its hydroxamate moiety rather than through its phosphate. These results have stimulated the present theoretical investigation in which we resort to the SIBFA polarizable molecular mechanics procedure to unravel the structural and energetical aspects of 5PAH and 5PAA binding to a 164-residue model of PMI. Consistent with the experimental results, our theoretical studies indicate that the complexation of PMI by 5PAH is much more favorable than by 5PAA, and that in the 5PAH complex, Zn(II) ligation by hydroxamate is much more favorable than by phosphate. Validations by parallel quantum-chemical computations on model of the recognition site extracted from the PMI-inhibitor complexes, and totaling up to 140 atoms, showed the values of the SIBFA intermolecular interaction energies in such models to be able to reproduce the quantum-chemistry ones with relative errors < 3%. On the basis of the PMI-5PAH SIBFA energy-minimized structure, we report the first hypothesis of a detailed view of the active site of the zinc PMI complexed to the high-energy intermediate analogue inhibitor, which allows us to identify active site residues likely involved in the proton transfer between the two adjacent carbons of the substrates.
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Affiliation(s)
- Celine Roux
- Laboratoire de Chimie Bioorganique et Bioinorganique, CNRS-UMR 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Bâtiment 420, Université Paris-Sud XI, 15 rue Georges Clémenceau, 91405 Orsay, France
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Upadhyay S, Shaw BD. A phosphoglucose isomerase mutant in Aspergillus nidulans is defective in hyphal polarity and conidiation. Fungal Genet Biol 2006; 43:739-51. [PMID: 16798030 DOI: 10.1016/j.fgb.2006.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 05/09/2006] [Accepted: 05/15/2006] [Indexed: 10/24/2022]
Abstract
Upon germination Aspergillus nidulans swoM1 exhibits abnormal development by extending a primary germ tube that quickly reverts to isotropic growth and results in an enlarged, swollen apex with pronounced wall thickenings. Apical lysis occurs in 38% of the germlings. A point mutation in the AN6037.3 gene encoding the only phosphoglucose isomerase in A. nidulans is responsible for the defect. Loss of polarity is bypassed when glucose is replaced with alternate carbon sources but in all cases the mutant is unable to conidiate due to a block in conidiophore development at vesicle formation. In conidiophores SwoM::GFP localizes to multiple punctate, foci within each actively growing cell type, and to multiple foci in mature dormant conidia. In hyphae SwoM::GFP localized to two rings spanning the center of mature septa. In hyphae localization is concentrated at actively growing hyphal tips.
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Affiliation(s)
- Srijana Upadhyay
- Program for Biology of Filamentous Fungi, Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA
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18
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Wills EA, Redinbo MR, Perfect JR, Poeta MD. New potential targets for antifungal development. ACTA ACUST UNITED AC 2005. [DOI: 10.1517/14728222.4.3.265] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Jeong HY, Kim H, Han DM, Jahng KY, Chae KS. Expression of the mnpA gene that encodes the mannoprotein of Aspergillus nidulans is dependent on fadA and flbA as well as veA. Fungal Genet Biol 2003; 38:228-36. [PMID: 12620259 DOI: 10.1016/s1087-1845(02)00527-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The single copy mnpA gene that encodes a mannoprotein of Aspergillus nidulans and its cDNA were isolated from the genomic and cDNA libraries, respectively. The determined nucleotide sequences of the genomic DNA and its cDNA revealed that the gene has an open-reading frame of 261 amino acids without introns. The deduced amino acid sequence showed a 60% identity to that of Aspegillus fumigatus galactomannoprotein MP1. The mnpA gene was expressed more abundantly in the wild-type than in the veA-null mutant. It was expressed at a lower level in fadA-null mutants, veA(+) or veA1 (regardless of their genetic background), than in the fadA(+) strain. However, the expression level was slightly higher in the veA(+) DeltafadA strain than in the veA1 DeltafadA strain. Furthermore, the amount of the mnpA transcript was higher in the flbA(+) strain than in the flbA-null mutant. These results indicate that the fadA and flbA genes in addition to the veA gene are necessary for the mnpA expression. The mnpA gene was expressed highly in vegetative mycelia and at a reduced level in sexual structures, but not in conidia. Its expression was almost constitutive during asexual development up to 18h after the transfer of mycelial balls onto a solid medium, and decreased thereafter. During sexual development, its expression reached its maximum 0-20h after the induction of sexual development, and then decreased thereafter. The mnpA-null mutant, that was still viable, showed no phenotypic difference in development, growth rate, protein secretion, and germination of both the ascospores and conidia from the wild-type. This suggests that the mannoprotein that is encoded by the mnpA gene is dispensable.
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Affiliation(s)
- Hyo-Young Jeong
- Division of Biological Sciences, Basic Science Research Institute, Chonbuk National University, Chonju, 561-756, Chonbuk, Republic of Korea
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Kim MW, Agaphonov MO, Kim JY, Rhee SK, Kang HA. Sequencing and functional analysis of the Hansenula polymorpha genomic fragment containing the YPT1 and PMI40 genes. Yeast 2002; 19:863-71. [PMID: 12112240 DOI: 10.1002/yea.881] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A 6.0 kb genomic DNA segment was isolated by its ability to rescue the temperature-sensitive growth defect and the hypersensitivity to sodium deoxycholate of a spontaneous vanadate-resistant mutant derived from Hansenula polymorpha DL-1. The genomic fragment contains four open reading frames homologous to the Saccharomyces cerevisiae genes YPT1 (which codes for a GTP-binding protein; 75% amino acid identity), PMI40 (encoding phosphomannose isomerase; 61% identity), YLR065c (30% identity) and CST13 (28% identity). The H. polymorpha YPT1 homologue (HpYPT1) was found to be responsible for the complementation of the temperature-sensitive phenotype and the sodium deoxycholate sensitivity of the mutant strain. Disruption of the H. polymorpha PMI40 homologue (HpPMI40) resulted in the auxotrophic requirement for D-mannose. The heterologous expressions of HpYPT1 and HpPMI40 were able to complement the temperature-sensitive phenotype of S. cerevisiae ypt1-1 mutant and the mannose auxotrophy of S. cerevisiae pmi40 null mutant, respectively, indicating that the H. polymorpha genes encode the functional homologues of S. cerevisiae YPT1 and PMI40 proteins. The nucleotide sequence has been submitted to GenBank under Accession No. AF454544.
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Affiliation(s)
- Moo Woong Kim
- Biomolecular Process Engineering Laboratory, Korea Research Institute of Bioscience and Biotechnology, Oun-dong 52, Yusong-gu, Taejon 305-600, Korea
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Wills EA, Roberts IS, Del Poeta M, Rivera J, Casadevall A, Cox GM, Perfect JR. Identification and characterization of the Cryptococcus neoformans phosphomannose isomerase-encoding gene, MAN1, and its impact on pathogenicity. Mol Microbiol 2001; 40:610-20. [PMID: 11359567 DOI: 10.1046/j.1365-2958.2001.02401.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The polysaccharide capsule surrounding Cryptococcus neoformans comprises manose, xylose and glucuronic acid, of which mannose is the major constituent. The GDP-mannose biosynthesis pathway is highly conserved in fungi and consists of three key enzymes: phosphomannose isomerase (PMI), phosphomannomutase (PMM) and GDP-mannose pyrophosphorylase (GMP). The MAN1 gene, encoding for the PMI enzyme, was isolated and sequenced from C. neoformans, and a disruption of the MAN1 gene was generated. One MAN1 disruption mutant, man1, which showed poor capsule formation, reduced polysaccharide secretion and morphological abnormalities, was chosen for virulence studies. In both the rabbit and the mouse models of invasive cryptococcosis, man1 was shown to be severely impaired in its virulence, with complete elimination of the yeast from the host. A reconstituted strain of man1 was constructed using gene replacement at the native locus. The wild-type and reconstituted strains were significantly more virulent than the knock-out mutant in both animal models. Our findings reveal that PMI activity is essential for the survival of C. neoformans in the host. The fact that the man1 mutant was not pathogenic suggests that blocking mannose synthesis could be fungicidal in the mammalian host and thus an excellent target for antifungal drug development.
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Affiliation(s)
- E A Wills
- University of Manchester, School of Biological Sciences, 1.800 Stopford Building, Manchester M13 9PT, UK
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Garami A, Ilg T. The role of phosphomannose isomerase in Leishmania mexicana glycoconjugate synthesis and virulence. J Biol Chem 2001; 276:6566-75. [PMID: 11084042 DOI: 10.1074/jbc.m009226200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphomannose isomerase (PMI) catalyzes the reversible interconversion of fructose 6-phosphate and mannose 6-phosphate, which is the first step in the biosynthesis of activated mannose donors required for the biosynthesis of various glycoconjugates. Leishmania species synthesize copious amounts of mannose-containing glycolipids and glycoproteins, which are involved in virulence of these parasitic protozoa. To investigate the role of PMI for parasite glycoconjugate synthesis, we have cloned the PMI gene (lmexpmi) from Leishmania mexicana, generated gene deletion mutants (Delta lmexpmi), and analyzed their phenotype. Delta lmexpmi mutants lack completely the high PMI activity found in wild type parasites, but are, in contrast to fungi, able to grow in media deficient for free mannose. The mutants are unable to synthesize phosphoglycan repeats [-6-Gal beta 1-4Man alpha 1-PO(4)-] and mannose-containing glycoinositolphospholipids, and the surface expression of the glycosylphosphatidylinositol-anchored dominant surface glycoprotein leishmanolysin is strongly decreased, unless the parasite growth medium is supplemented with mannose. The Delta lmexpmi mutant is attenuated in infections of macrophages in vitro and of mice, suggesting that PMI may be a target for anti-Leishmania drug development. L. mexicana Delta lmexpmi provides the first conditional mannose-controlled system for parasite glycoconjugate assembly with potential applications for the investigation of their biosynthesis, intracellular sorting, and function.
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Affiliation(s)
- A Garami
- Max-Planck-Institut für Biologie, Corrensstrasse 38, Tübingen 72076, Federal Republic of Germany
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Epstein L, Lusnak K, Kaur S. Transformation-mediated developmental mutants of Glomerella graminicola. Fungal Genet Biol 1998; 23:189-203. [PMID: 9578632 DOI: 10.1006/fgbi.1997.1029] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glomerella graminicola transformants were generated by insertional plasmid mutagenesis. Five transformants with developmental mutant phenotypes that segregated in crosses as single-gene mutations were selected. In four transformants, the mutant phenotype cosegregated with the inserted plasmid DNA. At least three of the mutants result from gene disruption, as demonstrated by recovery of the mutant phenotypes after transformation of wild type with "rescued" plasmid DNA. Whereas the wild type produces uninucleate, salmon-colored conidia, the tagged mutant M26 has white conidia. After exposure to either UV light or singlet oxygen, the percentage germination of M26 conidia is reduced compared to that of the wild-type conidia, indicating that the spore pigment confers protection from UV light and singlet oxygen. The tagged mutant T30 has weakened walls; falcate conidia rupture and hyphae have swollen regions unless the medium is amended with an osmoticum. The tagged mutant T29 has falcate conidia with one to four nuclei; wild-type falcate conidia are uninucleate. Two other mutants, one which grows slowly and one having conidia with increased curvature, are also described.
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Affiliation(s)
- L Epstein
- Department of Environmental Science, Policy and Management, University of California, Berkeley 94720-3112, USA
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Fungal Spore Germination: Insights from the Molecular Genetics ofAspergillus nidulansandNeurospora crassa. Fungal Genet Biol 1997. [DOI: 10.1006/fgbi.1997.0975] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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