18 results on '"Oide S"'
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2. 偽ディオニシウス・アレオパギタの「神秘神学」
- Author
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Oide, S
- Published
- 1966
3. Fluoroscopy- and Endoscopy-Guided Transoral Sclerotherapy Using Foamed Polidocanol for Oropharyngolaryngeal Venous Malformations in a Hybrid Operation Room: A Case Series.
- Author
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Ishikawa K, Maeda T, Funayama E, Murao N, Miura T, Sasaki Y, Seo D, Mitamura S, Oide S, Yamamoto Y, and Sasaki S
- Abstract
Background: Treatment of oropharyngolaryngeal venous malformations (VMs) remains challenging. This study evaluated the effectiveness and safety of fluoroscopy- and endoscopy-guided transoral sclerotherapy for oropharyngolaryngeal VMs in a hybrid operation room (OR). Methods: Patients with oropharyngolaryngeal VMs who underwent transoral sclerotherapy in a hybrid OR were enrolled. Results: Fourteen patients (six females, eight males; median age of 26 years; range, 4-71 years) were analyzed. The symptoms observed were breathing difficulties (n = 3), snoring (n = 2), sleep apnea (n = 1), and swallowing difficulties (n = 1). Lesions were extensive in the face and neck (n = 9) and limited in the oropharyngolarynx (n = 5). A permanent tracheostomy was performed on two patients, while a temporary tracheostomy was performed on five patients. The treated regions were the soft palate (n = 8), pharynx (n = 7), base of the tongue (n = 4), and epiglottis (n = 1). The median number of sclerotherapy sessions was 2.5 (range, 1-9). The median follow-up duration was 81 months (range, 6-141). Treatment outcomes were graded as excellent (n = 2), good (n = 7), or fair (n = 5). The post-treatment complication was bleeding (n = 1), resulting in an urgent tracheostomy. Conclusions: Fluoroscopy- and endoscopy-guided transoral sclerotherapy in a hybrid OR can be effective and safe for oropharyngolaryngeal VMs.
- Published
- 2024
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4. Efficacy and Safety of the Surgery-First Approach Compared to the Chemotherapy-First Approach for Treating Low-Risk Gestational Trophoblastic Neoplasia: A Systematic Review and Meta-Analysis.
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Kamijo K, Ishida K, Oide S, Anan K, Taito S, Kataoka Y, and Chikazawa K
- Abstract
For gestational trophoblastic neoplasia (GTN) affecting women of reproductive age, the chemotherapy-first approach is often preferred over the surgery-first approach. Low-risk GTN is treated with a chemotherapy-first approach, but the number of courses required can affect fertility. A surgery-first approach may decrease the number of chemotherapy courses, but its efficacy and safety compared to a chemotherapy-first approach are unclear. Thus, we investigated the efficacy and safety of the surgery-first approach compared to the chemotherapy-first approach in treating low-risk GTN. We searched the MEDLINE, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform databases for relevant articles in July 2023. A systematic review and meta-analysis of outcome measures were conducted using a random-effects model. The primary outcomes were remission, the mean number of chemotherapy courses required to cure, and adverse events. The certainty of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation approach. This study protocol was registered in the Open Science Framework (https://osf.io/kysvn/). Studies for low-risk GTN included a qualitative synthesis (with 2,192 participants and ten studies, eight of which were about second uterine curettage and two about hysterectomy) and a meta-analysis (with 138 participants and two randomized controlled trials (RCTs) that compared first-line treatments of second uterine curettage and chemotherapy). Second uterine curettage may result in little to no difference in remission (risk ratio: 1.00, 95% confidence interval: 0.96-1.05; low certainty) and a slight reduction in adverse events (risk ratio: 0.87, 95% confidence interval: 0.47-1.60; low certainty). The evidence is very uncertain on the mean number of chemotherapy courses (mean difference: 2.84 lower, 95% confidence interval: 7.31 lower to 1.63 higher; very low certainty). Based on clinical outcomes, second uterine curettage can be comparable to the chemotherapy-first approach as a first-line treatment option for low-risk GTN; however, the overall certainty of the evidence was low or very low., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2023, Kamijo et al.)
- Published
- 2023
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5. Carbohydrate-binding property of a cell wall integrity and stress response component (WSC) domain of an alcohol oxidase from the rice blast pathogen Pyricularia oryzae.
- Author
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Oide S, Tanaka Y, Watanabe A, and Inui M
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- Alcohol Oxidoreductases genetics, Alcohol Oxidoreductases metabolism, Ascomycota genetics, Ascomycota metabolism, Chitin metabolism, Fungal Proteins genetics, Fungal Proteins metabolism, Gene Expression, Oryza, Pichia genetics, Pichia metabolism, Plant Diseases microbiology, Protein Binding, Protein Domains, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins metabolism, Sequence Deletion, Xylans metabolism, Alcohol Oxidoreductases chemistry, Ascomycota enzymology, Cell Wall metabolism, Fungal Proteins chemistry, Polysaccharides metabolism
- Abstract
The cell wall integrity and stress response component (WSC) domain was first described in the Wsc-family protein of the yeast Saccharomyces cerevisiae, and later found in diverse eukaryotic organisms. Due solely to their presence in the Wsc-family proteins working as a plasma membrane sensor for surface stress and in a fungal β-1,3-exoglucanse, WSC domains have been presumed to possess carbohydrate-binding property without any experimental evidence. Aiming at elucidation of function(s) of WSC domains, we characterized a WSC domain-containing alcohol oxidase from the rice blast pathogen Pyricularia oryzae (PoAlcOX). Recombinant PoAlcOX produced with Pichia pastoris showed alcohol oxidase activity toward a wide range of substrates including two aliphatic alcohols, a branched-chain alcohol, a diol, and a polyol. Deletion of the WSC domain virtually unaffected oxidation of these substrates by PoAlcOX, indicating that the domain makes no contribution to the catalytic activity. In analogy to some carbohydrate-binding modules, we inferred that the WSC domain plays a role in protein anchoring, and evaluated binding capability of PoAlcOX to a set of polysaccharide components of fungal and plant cell walls. This revealed that PoAlcOX binds to xylans and fungal chitin/β-1,3-glucan in the WSC domain-dependent manner, demonstrating for the first time the carbohydrate-binding property of the domain. Additionally, we provide evidence that PoAlcOX immobilized on birch wood xylan retains the catalytic activity. Overall, the data we collected suggest that the role of the WSC domain of PoAlcOX is not recognition of substrates but attaching the enzyme to plant and/or fungal cell wall., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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6. Open fan sign: An ultrasound finding suggesting postpartum intrauterine forgotten gauze.
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Wang L, Kuwata T, Horiuchi I, Ariga H, Imai K, Ko H, Kimura A, Chikazawa K, Oide S, and Takagi K
- Abstract
Gauze counting is regarded as the most essential way to prevent forgotten gauze inside the body during any surgery. However, incident may still occur due to artificial mistake. An open fan sign on ultrasonography may indicate a gauze left in the intrauterine cavity.
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- 2018
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7. Trehalose acts as a uridine 5'-diphosphoglucose-competitive inhibitor of trehalose 6-phosphate synthase in Corynebacterium glutamicum.
- Author
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Oide S and Inui M
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- Amino Acid Substitution, Animals, Bacterial Proteins chemistry, Bacterial Proteins genetics, Bacterial Proteins metabolism, Binding, Competitive, Drug Resistance, Bacterial, Feedback, Physiological, Glucosyltransferases chemistry, Glucosyltransferases genetics, Glucosyltransferases metabolism, Hot Temperature, Models, Molecular, Moths genetics, Mutation, Missense, Phosphoric Monoester Hydrolases metabolism, Protein Conformation, Protein Denaturation, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins metabolism, Sequence Alignment, Sequence Homology, Nucleic Acid, Species Specificity, Bacterial Proteins antagonists & inhibitors, Corynebacterium glutamicum enzymology, Glucosyltransferases antagonists & inhibitors, Trehalose pharmacology, Uridine Diphosphate pharmacology
- Abstract
Trehalose is a compatible solute widely distributed in nature. The most prevalent pathway for its synthesis starts from condensation of glucose 6-phosphate (Glc6P) and uridine 5'-diphosphoglucose (UDP-Glc) catalyzed by trehalose 6-phosphate synthase (TPS). A previous laboratory evolution experiment with the bacterium Corynebacterium glutamicum generated strains adapted to supraoptimal temperatures, and the R328H substitution of the TPS encoded by otsA was shown to be associated with thermotolerance acquired by the evolved strains. In this study, we found that the OtsA:R328H substitution promotes both intra- and extracellular trehalose accumulation and demonstrated that build-up of intracellular trehalose accounts for the OtsA
R 328H -dependent thermotolerance, using the mycobacterial trehalose-specific transporter. Counterintuitively, characterization of the recombinant OtsA proteins revealed that the mutation downshifts the temperature optimum of OtsA. A search for the molecular basis of OtsAR 328H -dependent enhancement of trehalose synthesis led to the unexpected findings that trehalose is an effective inhibitor of OtsA and that OtsAR 328H is highly tolerant to the trehalose-mediated inhibition. The only available report on such feedback regulation of TPS is for the silk moth from over 50 years ago [Murphy TA and Wyatt GR (1965) J Biol Chem 240, 1500-1508]. While trehalose acts as a Glc6P-competitive inhibitor in the silk moth, the disaccharide was found to inhibit OtsA in a UDP-Glc-competitive manner in C. glutamicum, suggesting independent origins of the negative feedback regulations found for the two species. We showed that overexpression of the wild-type OtsA counteracts the trehalose-dependent regulation and restores the evolved strain-like phenotype to the isogenic wild-type otsA revertant, demonstrating that thermotolerance conferred by OtsAR 328H is attributable to its feedback-resistant property., (© 2017 Federation of European Biochemical Societies.)- Published
- 2017
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8. Thermal and solvent stress cross-tolerance conferred to Corynebacterium glutamicum by adaptive laboratory evolution.
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Oide S, Gunji W, Moteki Y, Yamamoto S, Suda M, Jojima T, Yukawa H, and Inui M
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- Corynebacterium glutamicum genetics, Corynebacterium glutamicum physiology, DNA, Bacterial chemistry, DNA, Bacterial genetics, Gene Expression Profiling, Genome, Bacterial, Molecular Sequence Data, Mutation, Missense, Organisms, Genetically Modified genetics, Organisms, Genetically Modified physiology, Sequence Analysis, DNA, Sequence Deletion, Serial Passage, Adaptation, Biological, Corynebacterium glutamicum drug effects, Corynebacterium glutamicum radiation effects, Hot Temperature, Solvents toxicity
- Abstract
Reinforcing microbial thermotolerance is a strategy to enable fermentation with flexible temperature settings and thereby to save cooling costs. Here, we report on adaptive laboratory evolution (ALE) of the amino acid-producing bacterium Corynebacterium glutamicum under thermal stress. After 65 days of serial passage of the transgenic strain GLY3, in which the glycolytic pathway is optimized for alanine production under oxygen deprivation, three strains adapted to supraoptimal temperatures were isolated, and all the mutations they acquired were identified by whole-genome resequencing. Of the 21 mutations common to the three strains, one large deletion and two missense mutations were found to promote growth of the parental strain under thermal stress. Additive effects on thermotolerance were observed among these mutations, and the combination of the deletion with the missense mutation on otsA, encoding a trehalose-6-phosphate synthase, allowed the parental strain to overcome the upper limit of growth temperature. Surprisingly, the three evolved strains acquired cross-tolerance for isobutanol, which turned out to be partly attributable to the genomic deletion associated with the enhanced thermotolerance. The deletion involved loss of two transgenes, pfk and pyk, encoding the glycolytic enzymes, in addition to six native genes, and elimination of the transgenes, but not the native genes, was shown to account for the positive effects on thermal and solvent stress tolerance, implying a link between energy-producing metabolism and bacterial stress tolerance. Overall, the present study provides evidence that ALE can be a powerful tool to refine the phenotype of C. glutamicum and to investigate the molecular bases of stress tolerance., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
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9. Individual and combined roles of malonichrome, ferricrocin, and TAFC siderophores in Fusarium graminearum pathogenic and sexual development.
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Oide S, Berthiller F, Wiesenberger G, Adam G, and Turgeon BG
- Abstract
Intra- and extracellular iron-chelating siderophores produced by fungal non-ribosomal peptide synthetases have been shown to be involved in reproductive and pathogenic developmental processes and in iron and oxidative stress management. Here we report individual and combined contributions of three of these metabolites to developmental success of the destructive cereal pathogen Fusarium graminearum. In previous work, we determined that deletion of the NPS2 gene, responsible for intracellular siderophore biosynthesis, results in inability to produce sexual spores when mutants of this homothallic ascomycete are selfed. Deletion of the NPS6 gene, required for extracellular siderophore biosynthesis, does not affect sexual reproduction but results in sensitivity to iron starvation and oxidative stress and leads to reduced virulence to the host. Building on this, we report that double mutants lacking both NPS2 and NPS6 are augmented in all collective phenotypes of single deletion strains (i.e., abnormal sexual and pathogenic development, hypersensitivity to oxidative and iron-depletion stress), which suggests overlap of function. Using comparative biochemical analysis of wild-type and mutant strains, we show that NPS1, a third gene associated with siderophore biosynthesis, is responsible for biosynthesis of a second extracellular siderophore, malonichrome. nps1 mutants fail to produce this metabolite. Phenotypic characterization reveals that, although single nps1 mutants are like wild-type with respect to sexual development, hypersensitivity to ROS and iron-depletion stress, and virulence to the host, triple nps1nps2nps6 deletion strains, lacking all three siderophores, are even more impaired in these attributes than double nps2nps6 strains. Thus, combinatorial mutants lacking key iron-associated genes uncovered malonichrome function. The intimate connection between presence/absence of siderophores and resistance/sensitivity to ROS is central to sexual and pathogenic development.
- Published
- 2015
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10. Reductive iron assimilation and intracellular siderophores assist extracellular siderophore-driven iron homeostasis and virulence.
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Condon BJ, Oide S, Gibson DM, Krasnoff SB, and Turgeon BG
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- Ascomycota cytology, Ascomycota genetics, Ascomycota pathogenicity, Ceruloplasmin genetics, Ceruloplasmin metabolism, Fungal Proteins metabolism, Homeostasis, Hydrogen Peroxide metabolism, Iron pharmacology, Iron Deficiencies, Membrane Transport Proteins genetics, Membrane Transport Proteins metabolism, Mutation, Oxidation-Reduction, Oxidative Stress, Peptide Synthases genetics, Peptide Synthases metabolism, Phenotype, Plant Leaves cytology, Plant Leaves microbiology, Siderophores isolation & purification, Siderophores metabolism, Spores, Fungal, Virulence, Zea mays cytology, Ascomycota physiology, Fungal Proteins genetics, Gene Expression Regulation, Fungal, Iron metabolism, Plant Diseases microbiology, Zea mays microbiology
- Abstract
Iron is an essential nutrient and prudent iron acquisition and management are key traits of a successful pathogen. Fungi use nonribosomally synthesized secreted iron chelators (siderophores) or reductive iron assimilation (RIA) mechanisms to acquire iron in a high affinity manner. Previous studies with the maize pathogen Cochliobolus heterostrophus identified two genes, NPS2 and NPS6, encoding different nonribosomal peptide synthetases responsible for biosynthesis of intra- and extracellular siderophores, respectively. Deletion of NPS6 results in loss of extracellular siderophore biosynthesis, attenuated virulence, hypersensitivity to oxidative and iron-depletion stress, and reduced asexual sporulation, while nps2 mutants are phenotypically wild type in all of these traits but defective in sexual spore development when NPS2 is missing from both mating partners. Here, it is reported that nps2nps6 mutants have more severe phenotypes than both nps2 and nps6 single mutants. In contrast, mutants lacking the FTR1 or FET3 genes encoding the permease and ferroxidase components, respectively, of the alternate RIA system, are like wild type in all of the above phenotypes. However, without supplemental iron, combinatorial nps6ftr1 and nps2nps6ftr1 mutants are less virulent, are reduced in growth, and are less able to combat oxidative stress and to sporulate asexually, compared with nps6 mutants alone. These findings demonstrate that, while the role of RIA in metabolism and virulence is overshadowed by that of extracellular siderophores as a high-affinity iron acquisition mechanism in C. heterostrophus, it functions as a critical backup for the fungus.
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- 2014
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11. Quantitative trait locus analysis of resistance to panicle blast in the rice cultivar Miyazakimochi.
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Ishihara T, Hayano-Saito Y, Oide S, Ebana K, La NT, Hayashi K, Ashizawa T, Suzuki F, and Koizumi S
- Abstract
Background: Rice blast is a destructive disease caused by Magnaporthe oryzae, and it has a large impact on rice production worldwide. Compared with leaf blast resistance, our understanding of panicle blast resistance is limited, with only one panicle blast resistance gene, Pb1, isolated so far. The japonica cultivar Miyazakimochi shows resistance to panicle blast, yet the genetic components accounting for this resistance remain to be determined., Results: In this study, we evaluated the panicle blast resistance of populations derived from a cross between Miyazakimochi and the Bikei 22 cultivar, which is susceptible to both leaf and panicle blast. The phenotypic analyses revealed no correlation between panicle blast resistance and leaf blast resistance. Quantitative trait locus (QTL) analysis of 158 recombinant inbred lines using 112 developed genome-wide and 35 previously reported polymerase chain reaction (PCR) markers revealed the presence of two QTLs conferring panicle blast resistance in Miyazakimochi: a major QTL, qPbm11, on chromosome 11; and a minor QTL, qPbm9, on chromosome 9. To clarify the contribution of these QTLs to panicle blast resistance, 24 lines homozygous for each QTL were selected from 2,818 progeny of a BC2F7 backcrossed population, and characterized for disease phenotypes. The panicle blast resistance of the lines harboring qPbm11 was very similar to the resistant donor parental cultivar Miyazakimochi, whereas the contribution of qPbm9 to the resistance was small. Genotyping of the BC2F7 individuals highlighted the overlap between the qPbm11 region and a locus of the panicle blast resistance gene, Pb1. Reverse transcriptase PCR analysis revealed that the Pb1 transcript was absent in the panicles of Miyazakimochi, demonstrating that qPbm11 is a novel genetic component of panicle blast resistance., Conclusions: This study revealed that Miyazakimochi harbors a novel panicle blast resistance controlled mainly by the major QTL qPbm11. qPbm11 is distinct from Pb1 and could be a genetic source for breeding panicle blast resistance, and will improve understanding of the molecular basis of host resistance to panicle blast.
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- 2014
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12. RabGAP22 is required for defense to the vascular pathogen Verticillium longisporum and contributes to stomata immunity.
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Roos J, Bejai S, Oide S, and Dixelius C
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- Abscisic Acid genetics, Abscisic Acid immunology, Abscisic Acid metabolism, Arabidopsis genetics, Arabidopsis immunology, Arabidopsis metabolism, Arabidopsis microbiology, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Brassinosteroids immunology, Brassinosteroids metabolism, Cell Nucleus genetics, Cell Nucleus immunology, Cell Nucleus metabolism, Cell Nucleus microbiology, Cyclopentanes immunology, Cyclopentanes metabolism, GTPase-Activating Proteins genetics, GTPase-Activating Proteins metabolism, Gene Expression Regulation, Plant, Immunity, Innate genetics, Oxylipins immunology, Oxylipins metabolism, Plant Diseases genetics, Plant Diseases immunology, Plant Diseases microbiology, Plant Growth Regulators genetics, Plant Growth Regulators immunology, Plant Growth Regulators metabolism, Plant Roots genetics, Plant Roots immunology, Plant Roots metabolism, Plant Roots microbiology, Plant Stomata genetics, Plant Stomata metabolism, Plant Stomata microbiology, Steroids, Heterocyclic immunology, Steroids, Heterocyclic metabolism, Arabidopsis Proteins immunology, GTPase-Activating Proteins immunology, Immunity, Innate immunology, Plant Stomata immunology, Verticillium immunology
- Abstract
Verticillium longisporum is a soil-borne pathogen with a preference for plants within the family Brassicaceae. Following invasion of the roots, the fungus proliferates in the plant vascular system leading to stunted plant growth, chlorosis and premature senescence. RabGTPases have been demonstrated to play a crucial role in regulating multiple responses in plants. Here, we report on the identification and characterization of the Rab GTPase-activating protein RabGAP22 gene from Arabidopsis, as an activator of multiple components in the immune responses to V. longisporum. RabGAP22Pro :GUS transgenic lines showed GUS expression predominantly in root meristems, vascular tissues and stomata, whereas the RabGAP22 protein localized in the nucleus. Reduced RabGAP22 transcript levels in mutants of the brassinolide (BL) signaling gene BRI1-associated receptor kinase 1, together with a reduction of fungal proliferation following BL pretreatment, suggested RabGAP22 to be involved in BL-mediated responses. Pull-down assays revealed serine:glyoxylate aminotransferase (AGT1) as an interacting partner during V. longisporum infection and bimolecular fluorescence complementation (BiFC) showed the RabGAP22-AGT1 protein complex to be localized in the peroxisomes. Further, fungal-induced RabGAP22 expression was found to be associated with elevated endogenous levels of the plant hormones jasmonic acid (JA) and abscisic acid (ABA). An inadequate ABA response in rabgap22-1 mutants, coupled with a stomata-localized expression of RabGAP22 and impairment of guard cell closure in response to V. longisporum and Pseudomonas syringae, suggest that RabGAP22 has multiple roles in innate immunity.
- Published
- 2014
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13. A novel role of PR2 in abscisic acid (ABA) mediated, pathogen-induced callose deposition in Arabidopsis thaliana.
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Oide S, Bejai S, Staal J, Guan N, Kaliff M, and Dixelius C
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- Arabidopsis drug effects, Arabidopsis genetics, Arabidopsis Proteins genetics, Ascomycota drug effects, Gene Expression Regulation, Plant drug effects, Glucan Endo-1,3-beta-D-Glucosidase genetics, Models, Biological, Phenotype, Plant Leaves drug effects, Plant Leaves metabolism, Plant Leaves microbiology, Pseudomonas syringae drug effects, RNA, Messenger genetics, RNA, Messenger metabolism, Salicylic Acid metabolism, Signal Transduction drug effects, Signal Transduction genetics, Abscisic Acid pharmacology, Arabidopsis metabolism, Arabidopsis microbiology, Arabidopsis Proteins metabolism, Ascomycota physiology, Glucan Endo-1,3-beta-D-Glucosidase metabolism, Glucans metabolism, Pseudomonas syringae physiology
- Abstract
Pathogenesis-related protein 2 (PR2) is known to play a major role in plant defense and general stress responses. Resistance against the fungal pathogen Leptosphaeria maculans in Arabidopsis requires abscisic acid (ABA), which promotes the deposition of callose, a β-1,3-glucan polymer. Here, we examined the role of PR2 in callose deposition in relation to ABA treatment and challenge with L. maculans and Pseudomonas syringae. Characterization of PR2-overexpressing plants and the knockout line indicated that PR2 negatively affects callose deposition. Recombinant PR2 purified from Pichia pastoris showed callose-degrading activity, and a considerable reduction in the callose-degrading activity was observed in the leaf extract of the PR2 knockout line compared with the wild-type. ABA pretreatment before challenge with L. maculans concomitantly repressed PR2 and enhanced callose accumulation. Likewise, overexpression of an ABA biosynthesis gene NCED3 resulted in reduced PR2 expression and increased callose deposition. We propose that ABA promotes callose deposition through the transcriptional repression of PR2 in Arabidopsis challenged by L. maculans and P. syringae. Callose by itself is likely to act antagonistically on salicylic acid (SA) defense signaling, suggesting that PR2 may function as a modulator of callose- and SA-dependent defense responses., (© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.)
- Published
- 2013
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14. ChLae1 and ChVel1 regulate T-toxin production, virulence, oxidative stress response, and development of the maize pathogen Cochliobolus heterostrophus.
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Wu D, Oide S, Zhang N, Choi MY, and Turgeon BG
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- Cloning, Molecular, Gene Expression Regulation, Fungal, Melanins metabolism, Mycotoxins genetics, Mycotoxins metabolism, Plant Diseases genetics, Plant Diseases microbiology, Reproduction, Asexual genetics, Zea mays microbiology, Ascomycota genetics, Ascomycota growth & development, Ascomycota metabolism, Ascomycota pathogenicity, Genes, Fungal physiology, Mycotoxins biosynthesis, Oxidative Stress genetics, Virulence genetics
- Abstract
LaeA and VeA coordinate secondary metabolism and differentiation in response to light signals in Aspergillus spp. Their orthologs, ChLae1 and ChVel1, were identified in the maize pathogen Cochliobolus heterostrophus, known to produce a wealth of secondary metabolites, including the host selective toxin, T-toxin. Produced by race T, T-toxin promotes high virulence to maize carrying Texas male sterile cytoplasm (T-cms). T-toxin production is significantly increased in the dark in wild type (WT), whereas Chvel1 and Chlae1 mutant toxin levels are much reduced in the dark compared to WT. Correspondingly, expression of T-toxin biosynthetic genes (Tox1) is up-regulated in the dark in WT, while dark-induced expression is much reduced/minimal in Chvel1 and Chlae1 mutants. Toxin production and Tox1 gene expression are increased in ChVEL1 overexpression (OE) strains grown in the dark and in ChLAE1 strains grown in either light or dark, compared to WT. These observations establish ChLae1 and ChVel1 as the first factors known to regulate host selective toxin production. Virulence of Chlae1 and Chvel1 mutants and OE strains is altered on both T-cms and normal cytoplasm maize, indicating that both T-toxin mediated super virulence and basic pathogenic ability are affected. Deletion of ChLAE1 or ChVEL1 reduces tolerance to H(2)O(2). Expression of CAT3, one of the three catalase genes, is reduced in the Chvel1 mutant. Chlae1 and Chvel1 mutants also show decreased aerial hyphal growth, increased asexual sporulation and female sterility. ChLAE1 OE strains are female sterile, while ChVEL1 OE strains are more fertile than WT. ChLae1 and ChVel1 repress expression of 1,8-dihydroxynaphthalene (DHN) melanin biosynthesis genes, and, accordingly, melanization is enhanced in Chlae1 and Chvel1 mutants, and reduced in OE strains. Thus, ChLae1 and ChVel1 positively regulate T-toxin biosynthesis, pathogenicity and super virulence, oxidative stress responses, sexual development, and aerial hyphal growth, and negatively control melanin biosynthesis and asexual differentiation.
- Published
- 2012
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15. Histidine kinase two-component response regulator proteins regulate reproductive development, virulence, and stress responses of the fungal cereal pathogens Cochliobolus heterostrophus and Gibberella zeae.
- Author
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Oide S, Liu J, Yun SH, Wu D, Michev A, Choi MY, Horwitz BA, and Turgeon BG
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- Ascomycota enzymology, Ascomycota genetics, Fungal Proteins genetics, Gibberella enzymology, Gibberella genetics, Histidine Kinase, Molecular Sequence Data, Protein Kinases genetics, Reproduction, Signal Transduction, Virulence, Ascomycota pathogenicity, Ascomycota physiology, Fungal Proteins metabolism, Gibberella pathogenicity, Gibberella physiology, Plant Diseases microbiology, Protein Kinases metabolism, Zea mays microbiology
- Abstract
Histidine kinase (HK) phosphorelay signaling is a major mechanism by which fungi sense their environment. The maize pathogen Cochliobolus heterostrophus has 21 HK genes, 4 candidate response regulator (RR) genes (SSK1, SKN7, RIM15, REC1), and 1 gene (HPT1) encoding a histidine phosphotransfer domain protein. Because most HKs are expected to signal through RRs, these were chosen for deletion. Except for pigment and slight growth alterations for rim15 mutants, no measurable altered phenotypes were detected in rim15 or rec1 mutants. Ssk1p is required for virulence and affects fertility and proper timing of sexual development of heterothallic C. heterostrophus. Pseudothecia from crosses involving ssk1 mutants ooze masses of single ascospores, and tetrads cannot be found. Wild-type pseudothecia do not ooze. Ssk1p represses asexual spore proliferation during the sexual phase, and lack of it dampens asexual spore proliferation during vegetative growth, compared to that of the wild type. ssk1 mutants are heavily pigmented. Mutants lacking Skn7p do not display any of the above phenotypes; however, both ssk1 and skn7 mutants are hypersensitive to oxidative and osmotic stresses and ssk1 skn7 mutants are more exaggerated in their spore-type balance phenotype and more sensitive to stress than single mutants. ssk1 mutant phenotypes largely overlap hog1 mutant phenotypes, and in both types of mutant, the Hog1 target gene, MST1, is not induced. ssk1 and hog1 mutants were examined in the homothallic cereal pathogen Gibberella zeae, and pathogenic and reproductive phases of development regulated by Ssk1 and Hog1 were found to mirror, but also vary from, those of C. heterostrophus.
- Published
- 2010
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16. Layers of defense responses to Leptosphaeria maculans below the RLM1- and camalexin-dependent resistances.
- Author
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Persson M, Staal J, Oide S, and Dixelius C
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- Arabidopsis microbiology, Arabidopsis Proteins genetics, Cyclopentanes, Cytochrome P-450 Enzyme System genetics, Ethylenes, Gene Expression Regulation, Plant, Lignin metabolism, Oxylipins, Plant Diseases microbiology, Salicylic Acid, Signal Transduction, Virulence Factors, Arabidopsis genetics, Fungi pathogenicity, Genes, Plant, Host-Pathogen Interactions genetics, Indoles metabolism, Plant Diseases genetics, Plant Growth Regulators genetics, Thiazoles metabolism
- Abstract
Plants have evolved different defense components to counteract pathogen attacks. The resistance locus resistance to Leptosphaeria maculans 1 (RLM1) is a key factor for Arabidopsis thaliana resistance to L. maculans. The present work aimed to reveal downstream defense responses regulated by RLM1. Quantitative assessment of fungal colonization in the host was carried out using quantitative polymerase chain reaction (qPCR) and GUS expression analyses, to further characterize RLM1 resistance and the role of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in disease development. Additional assessments of A. thaliana mutants were performed to expand our understanding of this pathosystem. Resistance responses such as lignification and the formation of vascular plugs were found to occur in an RLM1-dependent manner, in contrast to the RLM1-independent increase in reactive oxygen species at the stomata and hydathodes. Analyses of mutants defective in hormone signaling in the camalexin-free rlm1(Ler)pad3 background revealed a significant influence of JA and ET on symptom development and pathogen colonization. The overall results indicate that the defense responses of primary importance induced by RLM1 are all associated with physical barriers, and that responses of secondary importance involve complex cross-talk among SA, JA and ET. Our observations further suggest that ET positively affects fungal colonization.
- Published
- 2009
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17. Intracellular siderophores are essential for ascomycete sexual development in heterothallic Cochliobolus heterostrophus and homothallic Gibberella zeae.
- Author
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Oide S, Krasnoff SB, Gibson DM, and Turgeon BG
- Subjects
- Gene Deletion, Intracellular Fluid metabolism, Reproduction, Ascomycota genetics, Ascomycota growth & development, Gibberella genetics, Gibberella growth & development, Siderophores physiology
- Abstract
Connections between fungal development and secondary metabolism have been reported previously, but as yet, no comprehensive analysis of a family of secondary metabolites and their possible role in fungal development has been reported. In the present study, mutant strains of the heterothallic ascomycete Cochliobolus heterostrophus, each lacking one of 12 genes (NPS1 to NPS12) encoding a nonribosomal peptide synthetase (NRPS), were examined for a role in sexual development. One type of strain (Delta nps2) was defective in ascus/ascospore development in homozygous Delta nps2 crosses. Homozygous crosses of the remaining 11 Delta nps strains showed wild-type (WT) fertility. Phylogenetic, expression, and biochemical analyses demonstrated that the NRPS encoded by NPS2 is responsible for the biosynthesis of ferricrocin, the intracellular siderophore of C. heterostrophus. Functional conservation of NPS2 in both heterothallic C. heterostrophus and the unrelated homothallic ascomycete Gibberella zeae was demonstrated. G. zeae Delta nps2 strains are concomitantly defective in intracellular siderophore (ferricrocin) biosynthesis and sexual development. Exogenous application of iron partially restored fertility to C. heterostrophus and G. zeae Delta nps2 strains, demonstrating that abnormal sexual development of Delta nps2 strains is at least partly due to their iron deficiency. Exogenous application of the natural siderophore ferricrocin to C. heterostrophus and G. zeae Delta nps2 strains restored WT fertility. NPS1, a G. zeae NPS gene that groups phylogenetically with NPS2, does not play a role in sexual development. Overall, these data demonstrate that iron and intracellular siderophores are essential for successful sexual development of the heterothallic ascomycete C. heterostrophus and the homothallic ascomycete G. zeae.
- Published
- 2007
- Full Text
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18. NPS6, encoding a nonribosomal peptide synthetase involved in siderophore-mediated iron metabolism, is a conserved virulence determinant of plant pathogenic ascomycetes.
- Author
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Oide S, Moeder W, Krasnoff S, Gibson D, Haas H, Yoshioka K, and Turgeon BG
- Subjects
- Ascomycota pathogenicity, Base Sequence, Conserved Sequence, DNA Primers, Molecular Sequence Data, Oxidative Stress, Peptide Synthases chemistry, Siderophores biosynthesis, Virulence, Ascomycota enzymology, Iron metabolism, Peptide Synthases metabolism, Plants microbiology, Siderophores metabolism
- Abstract
NPS6, encoding a nonribosomal peptide synthetase, is a virulence determinant in the maize (Zea mays) pathogen Cochliobolus heterostrophus and is involved in tolerance to H(2)O(2). Deletion of NPS6 orthologs in the rice (Oryza sativa) pathogen, Cochliobolus miyabeanus, the wheat (Triticum aestivum) pathogen, Fusarium graminearum, and the Arabidopsis thaliana pathogen, Alternaria brassicicola, resulted in reduced virulence and hypersensitivity to H(2)O(2). Introduction of the NPS6 ortholog from the saprobe Neurospora crassa to the Deltanps6 strain of C. heterostrophus restored wild-type virulence to maize and tolerance to H(2)O(2), demonstrating functional conservation in filamentous ascomycete phytopathogens and saprobes. Increased sensitivity to iron depletion was identified as a conserved phenotype of Deltanps6 strains. Exogenous application of iron enhanced the virulence of Deltanps6 strains of C. heterostrophus, C. miyabeanus, F. graminearum, and A. brassicicola to each host. NPS6 is responsible for the biosynthesis of extracellular siderophores by C. heterostrophus, F. graminearum, and A. brassicicola. Application of the extracellular siderophore of A. brassicicola restored wild-type virulence of the DeltaAbnps6 strain to Arabidopsis. It is proposed that the role of extracellular siderophores in fungal virulence to plants is to supply an essential nutrient, iron, to their producers in planta and not to act as phytotoxins, depriving their hosts of iron.
- Published
- 2006
- Full Text
- View/download PDF
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