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Zou Z, Kaothien-Nakayama P, Nakayama H. Enhanced accumulation of γ-aminobutyric acid by deletion of aminotransferase genes involved in γ-aminobutyric acid catabolism in engineered Halomonas elongata. Appl Environ Microbiol 2024:e0073424. [PMID: 39133003 DOI: 10.1128/aem.00734-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/13/2024] [Indexed: 08/13/2024] Open
Abstract
Halomonas elongata OUT30018 is a moderately halophilic bacterium that synthesizes and accumulates ectoine as an osmolyte by activities of the enzymes encoded by the high salinity-inducible ectABC operon. Previously, we engineered a γ-aminobutyric acid (GABA)-producing H. elongata GOP-Gad (ΔectABC::mCherry-HopGadmut) from an ectoine-deficient mutant of this strain due to its ability to use high-salinity biomass waste as substrate. Here, to further increase GABA accumulation, we deleted gabT, which encodes GABA aminotransferase (GABA-AT) that catalyzes the first step of the GABA catabolic pathway, from the H. elongata GOP-Gad genome. The resulting strain H. elongata ZN3 (ΔectABC::mCherry-HopGadmut ΔgabT) accumulated 291 µmol/g cell dry weight (CDW) of GABA in the cells, which is a 1.5-fold increase from H. elongata GOP-Gad's 190 µmol/g CDW. This result has confirmed the role of GABA-AT in the GABA catabolic pathway. However, redundancy in endogenous GABA-AT activity was detected in a growth test, where a gabT-deletion mutant of H. elongata OUT30018 was cultured in a medium containing GABA as the sole carbon and nitrogen sources. Because L-2,4-diaminobutyric acid aminotransferase (DABA-AT), encoded by an ectB gene of the ectABC operon, shares sequence similarity with GABA-AT, a complementation analysis of the gabT and the ectB genes was performed in the H. elongata ZN3 genetic background to test the involvement of DABA-AT in the redundancy of GABA-AT activity. Our results indicate that the expression of DABA-AT can restore GABA-AT activity in H. elongata ZN3 and establish DABA-AT's aminotransferase activity toward GABA in vivo. IMPORTANCE In this study, we were able to increase the yield of GABA by 1.5 times in the GABA-producing H. elongata ZN3 strain by deleting the gabT gene, which encodes GABA-AT, the initial enzyme of the GABA catabolic pathway. We also report the first in vivo evidence for GABA aminotransferase activity of an ectB-encoded DABA-AT, confirming a longstanding speculation based on the reported in vitro GABA-AT activity of DABA-AT. According to our findings, the DABA-AT enzyme can catalyze the initial step of GABA catabolism, in addition to its known function in ectoine biosynthesis. This creates a cycle that promotes adequate substrate flow between the two pathways, particularly during the early stages of high-salinity stress response when the expression of the ectB gene is upregulated.
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Affiliation(s)
- Ziyan Zou
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Pulla Kaothien-Nakayama
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Hideki Nakayama
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
- Institute of Integrated Science and Technology, Nagasaki University, Nagasaki, Japan
- Organization for Marine Science and Technology, Nagasaki University, Nagasaki, Japan
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Yavarzadeh M, Anwar F, Saadi S, Saari N. Production of glycerolamines based conjugated γ-aminobutyric acids using microbial COX and LOX as successor enzymes to GAD. Enzyme Microb Technol 2023; 169:110282. [PMID: 37393814 DOI: 10.1016/j.enzmictec.2023.110282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/22/2023] [Accepted: 06/25/2023] [Indexed: 07/04/2023]
Abstract
Gamma-aminobutyric acid (γ-ABA) can be produced by various microorganisms including bacteria, fungi and yeasts using enzymatic bioconversion, microbial fermentation or chemical hydrolysis. Regenerating conjugated glycerol-amines is valid by the intervention of microbial cyclooxygenase [COX] and lipooxygenase [LOX] enzymes produced via lactobacillus bacteria (LAB) as successor enzymes to glutamate decarboxylases (GAD). Therefore, the aim of this review is to provide an overview on γ-ABA production, and microbiological achievements used in producing this signal molecule based on those fermenting enzymes. The formation of aminoglycerides based conjugated γ-ABA is considered the key substances in controlling the host defense against pathogens and is aimed in increasing the neurotransmission effects and in suppressing further cardiovascular diseases.
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Affiliation(s)
- Marjan Yavarzadeh
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Farooq Anwar
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia; Institute of Chemistry, University of Sargodha, Sargodha 40100, Pakistan.
| | - Sami Saadi
- Institute de la Nutrition, de l'Alimentation et des Technologies Agroalimetaires INATAA, Université des Frères Mentouri Constantine, 1, Route de Ain El Bey, Constantine 25000, Algeria; Laboratoire de Génie Agro-Alimentaire (GeniAAl), INATAA, Université Frères Mentouri Constantine, 1 UFC1, Route de Ain El Bey, Constantine 25000, Algeria
| | - Nazamid Saari
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
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Polozsányi Z, Kaliňák M, Babjak M, Šimkovič M, Varečka Ľ. How to enter the state of dormancy? A suggestion by Trichoderma atroviride conidia. Fungal Biol 2021; 125:934-949. [PMID: 34649680 DOI: 10.1016/j.funbio.2021.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 06/12/2021] [Accepted: 07/01/2021] [Indexed: 10/20/2022]
Abstract
It is generally accepted that conidia, propagules of filamentous fungi, exist in the state of dormancy. This state is defined mostly phenomenologically, e.g., by germination requirements. Its molecular characteristics are scarce and are concentrated on the water or osmolyte content, and/or respiration. However, a question of whether conidia are metabolic or ametabolic forms of life cannot be answered on the basis of available experimental data. In other words, are mature conidia open thermodynamic systems as are mycelia, or do they become closed upon the transition to the dormant state? In this article, we present observations which may help to define the transition of freshly formed conidia to the putative dormant forms using measurements of selected enzyme activities, 1H- and 13C-NMR and LC-MS-metabolomes, and 14C-bicarbonate or 45Ca2+ inward transport. We have found that Trichoderma atroviride and Aspergillus niger conidia arrest the 45Ca2+ uptake during the development stopping thereby the cyclic (i.e., bidirectional) Ca2+ flow existing in vegetative mycelia and conidia of T. atroviride across the cytoplasmic membrane. Furthermore, we have found that the activity of α-ketoglutarate dehydrogenase was rendered completely inactive after 3 weeks from the conidia formation unlike of other central carbon metabolism enzymes. This may explain the loss of conidial respiration. Finally, we found that conidia take up the H14CO3- and convert it into few stable compounds within 80 d of maturation, with minor quantitative differences in the extent of this process. The uptake of H13CO3- confirmed these observation and demonstrated the incorporation of H13CO3- even in the absence of exogenous substrates. These results suggest that T. atroviride conidia remain metabolically active during first ten weeks of maturation. Under these circumstances, their metabolism displays features similar to those of chemoautotrophic microorganisms. However, the Ca2+ homeostasis changed from the open to the closed thermodynamic state during the early period of conidial maturation. These results may be helpful for studying the conidial ageing and/or maturation, and for defining the conidial dormant state in biochemical terms.
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Affiliation(s)
- Zoltán Polozsányi
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovakia
| | - Michal Kaliňák
- Central Laboratories, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovakia
| | - Matej Babjak
- Department of Organic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovakia
| | - Martin Šimkovič
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovakia.
| | - Ľudovít Varečka
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovakia
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Plante S, Landry CR. Closely related budding yeast species respond to different ecological signals for spore activation. Yeast 2020; 38:81-89. [PMID: 33202071 DOI: 10.1002/yea.3538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/27/2020] [Accepted: 11/10/2020] [Indexed: 01/20/2023] Open
Abstract
Spore activation is one of the most important developmental decisions in fungi as it initiates the transition from dormant and stress-resistant cells to vegetative cells. Because in many species mating follows spore activation and germination, signals that trigger this developmental transition can also contribute to species reproductive barriers. Here, we examine the biochemical signals triggering spore activation in a natural species complex of budding yeast, Saccharomyces paradoxus (lineages SpA, SpB, SpC and SpC*). We first demonstrate that we can quantitatively monitor spore activation in these closely related lineages. Second, we dissect the composition of culture media to identify components necessary and/or sufficient to activate spores in the four lineages. We show that, contrary to expectation, glucose is necessary but not sufficient to trigger spore activation. We also show that two of the North American lineages (SpC and SpC*) diverge from the other North American (SpB) and European (SpA) lineages in terms of germination signal as their spore activation requires inorganic phosphate. Our results show that the way budding yeast interpret environmental conditions during spore activation diverged among closely related and incipient species, which means that it may play a role in their ecological differentiation and reproductive isolation. TAKE AWAY: Sensing of multiple compounds allows spore activation in non-domesticated budding yeast. Spore activation cues differ among Saccharomyces paradoxus lineages. Dextrose and phosphate signal activation in SpC and SpC* spores.
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Affiliation(s)
- Samuel Plante
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada.,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, Québec, Québec, Canada.,Département de biologie, Université Laval, Québec, Québec, Canada.,Département de biochimie, microbiologie et bio-informatique, Université Laval, Québec, Québec, Canada.,Centre de recherche en données massives (CRDM), Université Laval, Québec, Québec, Canada
| | - Christian R Landry
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada.,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), Université Laval, Québec, Québec, Canada.,Département de biologie, Université Laval, Québec, Québec, Canada.,Département de biochimie, microbiologie et bio-informatique, Université Laval, Québec, Québec, Canada.,Centre de recherche en données massives (CRDM), Université Laval, Québec, Québec, Canada
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A Brief Review on the Non-protein Amino Acid, Gamma-amino Butyric Acid (GABA): Its Production and Role in Microbes. Curr Microbiol 2019; 77:534-544. [PMID: 31844936 DOI: 10.1007/s00284-019-01839-w] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/03/2019] [Indexed: 12/26/2022]
Abstract
Gamma-Aminobutyric acid (GABA) is a non-protein amino acid widely distributed in nature. It is produced through irreversible α-decarboxylation of glutamate by enzyme glutamate decarboxylase (GAD). GABA and GAD have been found in plants, animals, and microorganisms. GABA is distributed throughout the human body and it is involved in the regulation of cardiovascular conditions such as blood pressure and heart rate, and plays a role in the reduction of anxiety and pain. Although researchers had produced GABA by chemical method earlier it became less acceptable as it pollutes the environment. Researchers now use a more promising microbial method for the production of GABA. In the drug and food industry, demand for GABA is immense. So, large scale conversion of GABA by microbes has got much attention. So this review focuses on the isolation source, production, and functions of GABA in the microbial system. We also summarize the mechanism of action of GABA and its shunt pathway.
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Shi H, Chen N, Zhu X, Liang S, Li L, Wang J, Lu J, Lin F, Liu X. F‐box proteins MoFwd1, MoCdc4 and MoFbx15 regulate development and pathogenicity in the rice blast fungusMagnaporthe oryzae. Environ Microbiol 2019; 21:3027-3045. [DOI: 10.1111/1462-2920.14699] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 06/05/2019] [Accepted: 05/27/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Huan‐Bin Shi
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
| | - Nan Chen
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
| | - Xue‐Ming Zhu
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
| | - Shuang Liang
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
| | - Lin Li
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
| | - Jiao‐Yu Wang
- Institute of Plant Protection MicrobiologyZhejiang Academy of Agricultural Science Hangzhou 310021 China
| | - Jian‐Ping Lu
- College of Life SciencesZhejiang University Hangzhou 310058 China
| | - Fu‐Cheng Lin
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
| | - Xiao‐Hong Liu
- State Key Laboratory for Rice Biology, Biotechnology InstituteZhejiang University Hangzhou 310058 China
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γ-Aminobutyric Acid (GABA): Biosynthesis, Role, Commercial Production, and Applications. STUDIES IN NATURAL PRODUCTS CHEMISTRY 2018. [DOI: 10.1016/b978-0-444-64057-4.00013-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Shaw DE. The Incidental Collection of Fungal Spores by Bees and the Collection of Spores in Lieu of Pollen. ACTA ACUST UNITED AC 2015. [DOI: 10.1080/0005772x.1990.11099059] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Abstract
SIGNIFICANCE Postharvest pathogens can start its attack process immediately after spores land on wounded tissue, whereas other pathogens can forcibly breach the unripe fruit cuticle and then remain quiescent for months until fruit ripens and then cause major losses. RECENT ADVANCES Postharvest fungal pathogens activate their development by secreting organic acids or ammonia that acidify or alkalinize the host ambient surroundings. CRITICAL ISSUES These fungal pH modulations of host environment regulate an arsenal of enzymes to increase fungal pathogenicity. This arsenal includes genes and processes that compromise host defenses, contribute to intracellular signaling, produce cell wall-degrading enzymes, regulate specific transporters, induce redox protectant systems, and generate factors needed by the pathogen to effectively cope with the hostile environment found within the host. Further, evidence is accumulating that the secreted molecules (organic acids and ammonia) are multifunctional and together with effect of the ambient pH, they activate virulence factors and simultaneously hijack the plant defense response and induce program cell death to further enhance their necrotrophic attack. FUTURE DIRECTIONS Global studies of the effect of secreted molecules on fruit pathogen interaction, will determine the importance of these molecules on quiescence release and the initiation of fungal colonization leading to fruit and vegetable losses.
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Affiliation(s)
- Noam Alkan
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel
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11
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Dhakal R, Bajpai VK, Baek KH. Production of gaba (γ - Aminobutyric acid) by microorganisms: a review. Braz J Microbiol 2012; 43:1230-41. [PMID: 24031948 PMCID: PMC3769009 DOI: 10.1590/s1517-83822012000400001] [Citation(s) in RCA: 292] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 06/07/2012] [Indexed: 11/21/2022] Open
Abstract
GABA (γ-aminobutyric acid) is a four carbon non-protein amino acid that is widely distributed in plants, animals and microorganisms. As a metabolic product of plants and microorganisms produced by the decarboxylation of glutamic acid, GABA functions as an inhibitory neurotransmitter in the brain that directly affects the personality and the stress management. A wide range of traditional foods produced by microbial fermentation contain GABA, in which GABA is safe and eco-friendly, and also has the possibility of providing new health-benefited products enriched with GABA. Synthesis of GABA is catalyzed by glutamate decarboxylase, therefore, the optimal fermentation condition is mainly based on the biochemical properties of the enzyme. Major GABA producing microorganisms are lactic acid bacteria (LAB), which make food spoilage pathogens unable to grow and act as probiotics in the gastrointestinal tract. The major factors affecting the production of GABA by microbial fermentation are temperature, pH, fermentation time and different media additives, therefore, these factors are summarized to provide the most up-dated information for effective GABA synthesis. There has been a huge accumulation of knowledge on GABA application for human health accompanying with a demand on natural GABA supply. Only the GABA production by microorganisms can fulfill the demand with GABA-enriched health beneficial foods.
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Affiliation(s)
- Radhika Dhakal
- School of Biotechnology, Yeungnam University, Gyeongsan , Gyeongbuk 712-749 , Republic of Korea
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12
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Use of 1H nuclear magnetic resonance to measure intracellular metabolite levels during growth and asexual sporulation in Neurospora crassa. EUKARYOTIC CELL 2011; 10:820-31. [PMID: 21460191 DOI: 10.1128/ec.00231-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Conidiation is an asexual sporulation pathway that is a response to adverse conditions and is the main mode of dispersal utilized by filamentous fungal pathogens for reestablishment in a more favorable environment. Heterotrimeric G proteins (consisting of α, β, and γ subunits) have been shown to regulate conidiation in diverse fungi. Previous work has demonstrated that all three of the Gα subunits in the filamentous fungus Neurospora crassa affect the accumulation of mass on poor carbon sources and that loss of gna-3 leads to the most dramatic effects on conidiation. In this study, we used (1)H nuclear magnetic resonance (NMR) to profile the metabolome of N. crassa in extracts isolated from vegetative hyphae and conidia from cultures grown under conditions of high or low sucrose. We compared wild-type and Δgna-3 strains to determine whether lack of gna-3 causes a significant difference in the global metabolite profile. The results demonstrate that the global metabolome of wild-type hyphae is influenced by carbon availability. The metabolome of the Δgna-3 strain cultured on both high and low sucrose is similar to that of the wild type grown on high sucrose, suggesting an overall defect in nutrient sensing in the mutant. However, analysis of individual metabolites revealed differences in wild-type and Δgna-3 strains cultured under conditions of low and high sucrose.
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Lowe RGT, Allwood JW, Galster AM, Urban M, Daudi A, Canning G, Ward JL, Beale MH, Hammond-Kosack KE. A combined ¹H nuclear magnetic resonance and electrospray ionization-mass spectrometry analysis to understand the basal metabolism of plant-pathogenic Fusarium spp. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1605-18. [PMID: 20718668 DOI: 10.1094/mpmi-04-10-0092] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Many ascomycete Fusarium spp. are plant pathogens that cause disease on both cereal and noncereal hosts. Infection of wheat ears by Fusarium graminearum and F. culmorum typically results in bleaching and a subsequent reduction in grain yield. Also, a large proportion of the harvested grain can be spoiled when the colonizing Fusarium mycelia produce trichothecene mycotoxins, such as deoxynivalenol (DON). In this study, we have explored the intracellular polar metabolome of Fusarium spp. in both toxin-producing and nonproducing conditions in vitro. Four Fusarium spp., including nine well-characterized wild-type field isolates now used routinely in laboratory experimentation, were explored. A metabolic "triple-fingerprint" was recorded using (1)H nuclear magnetic resonance and direct-injection electrospray ionization-mass spectroscopy in both positive- and negative-ionization modes. These combined metabolomic analyses revealed that this technique is sufficient to resolve different wild-type isolates and different growth conditions. Principal components analysis was able to resolve the four species explored-F. graminearum, F. culmorum, F. pseudograminearum, and F. venenatum-as well as individual isolate differences from the same species. The external nutritional environment was found to have a far greater influence on the metabolome than the genotype of the organism. Conserved responses to DON-inducing medium were evident and included increased abundance of key compatible solutes, such as glycerol and mannitol. In addition, the concentration of γ-aminobutyric acid was elevated, indicating that the cellular nitrogen status may be affected by growth on DON-inducing medium.
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Affiliation(s)
- Rohan G T Lowe
- Centre for Sustainable Pest and Disease Management, Department of Plant Pathology and Microbiology, Rothamsted Research, West Common, Harpenden, AL5 2JQ, UK
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Miyara I, Shafran H, Davidzon M, Sherman A, Prusky D. pH Regulation of ammonia secretion by Colletotrichum gloeosporioides and its effect on appressorium formation and pathogenicity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:304-16. [PMID: 20121452 DOI: 10.1094/mpmi-23-3-0304] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Host-tissue alkalinization via ammonia accumulation is key to Colletotrichum spp. colonization. Using macroarrays carrying C. gloeosporioides cDNAs, we monitored gene expression during the alkalinization process. A set of genes involved in synthesis and catabolism of ammonia accumulation were identified. Expression of NAD(+)-specific glutamate dehydrogenase (GDH2, encoding ammonia synthesis) and the ammonia exporter AMET were induced at pH 4.0 to 4.5. Conversely, ammonia uptake and transcript activation of the ammonia and glutamate importers (MEP and GLT, respectively) and glutamine synthase (GS1) were higher at pH 6.0 to 7.0. Accumulated ammonia in the wild-type mycelium decreased during ambient alkalinization, concurrent with increased GS1 expression. Deltapac1 mutants of C. gloeosporioides, which are sensitive to alkaline pH changes, showed upregulation of the acid-expressed GDH2 and downregulation of the alkaline-expressed GS1, resulting in 60% higher ammonia accumulation inside the mycelium. Deltagdh2 strains of C. gloeosporioides, impaired in ammonia production, showed 85% inhibition in appressorium formation followed by reduced colonization on avocado fruit (Persea americana cv. Fuerte) pericarp, while exogenic ammonia addition restored appressoria formation. Thus the modulation of genes involved in ammonia metabolism and catabolism by C. gloeosporioides is ambient pH-dependent. Aside from its contribution to necrotrophic stages, ammonia accumulation by germinating spores regulates appressorium formation and determines the initiation of biotrophic stages of avocado-fruit colonization by Colletotrichum spp.
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Affiliation(s)
- Itay Miyara
- Department Of Postharvest Sciences Of Fresh Produce, Agricultural Reserach Organization, The Volcani Center, Bet Dagan 50250, Israel
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15
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Tisch D, Schmoll M. Light regulation of metabolic pathways in fungi. Appl Microbiol Biotechnol 2009; 85:1259-77. [PMID: 19915832 PMCID: PMC2807966 DOI: 10.1007/s00253-009-2320-1] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 10/14/2009] [Accepted: 10/14/2009] [Indexed: 12/17/2022]
Abstract
Light represents a major carrier of information in nature. The molecular machineries translating its electromagnetic energy (photons) into the chemical language of cells transmit vital signals for adjustment of virtually every living organism to its habitat. Fungi react to illumination in various ways, and we found that they initiate considerable adaptations in their metabolic pathways upon growth in light or after perception of a light pulse. Alterations in response to light have predominantly been observed in carotenoid metabolism, polysaccharide and carbohydrate metabolism, fatty acid metabolism, nucleotide and nucleoside metabolism, and in regulation of production of secondary metabolites. Transcription of genes is initiated within minutes, abundance and activity of metabolic enzymes are adjusted, and subsequently, levels of metabolites are altered to cope with the harmful effects of light or to prepare for reproduction, which is dependent on light in many cases. This review aims to give an overview on metabolic pathways impacted by light and to illustrate the physiological significance of light for fungi. We provide a basis for assessment whether a given metabolic pathway might be subject to regulation by light and how these properties can be exploited for improvement of biotechnological processes.
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Affiliation(s)
- Doris Tisch
- Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, 1060 Vienna, Austria.
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Jaworski A, Sedlaczek L, Wilmańska D, Sasiak A, Strycharska A. Factors regulating the steroid 11-hydroxylation by non-germinating spores of Cunninghamella elegans (LENDNER). J Basic Microbiol 2007. [DOI: 10.1002/jobm.19820220506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Furch B, Steinberg C. Extraktion freier Aminosäuren aus Pilzsporen (Phycomyces blakesleeanus). ACTA ACUST UNITED AC 2007. [DOI: 10.1002/jpln.19771400506] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- B. Furch
- Botanischen Institut der Christian‐Albrechts‐Universität Kiel und dem Max Planck Institut für Limnologie
| | - Ch. Steinberg
- Botanischen Institut der Christian‐Albrechts‐Universität Kiel und dem Max Planck Institut für Limnologie
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Meijer S, Panagiotou G, Olsson L, Nielsen J. Physiological characterization of xylose metabolism inAspergillus niger under oxygen-limited conditions. Biotechnol Bioeng 2007; 98:462-75. [PMID: 17335061 DOI: 10.1002/bit.21397] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The physiology of Aspergillus niger was studied under different aeration conditions. Five different aeration rates were investigated in batch cultivations of A. niger grown on xylose. Biomass, intra- and extra-cellular metabolites profiles were determined and ten different enzyme activities in the central carbon metabolism were assessed. The focus was on organic acid production with a special interest in succinate production. The fermentations revealed that oxygen limitation significantly changes the physiology of the micro-organism. Changes in extra cellular metabolite profiles were observed, that is, there was a drastic increase in polyol production (erythritol, xylitol, glycerol, arabitol, and mannitol) and to a lesser extent in the production of reduced acids (malate and succinate). The intracellular metabolite profiles indicated changes in fluxes, since several primary metabolites, like the intermediates of the TCA cycle accumulated during oxygen limitation (on average three fold increase). Also the enzyme activities showed changes between the exponential growth phase and the oxygen limitation phase. In general, the oxygen availability has a significant impact on the physiology of this fungus causing dramatic alterations in the central carbon metabolism that should be taken into account in the design of A. niger as a succinate cell factory.
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Affiliation(s)
- S Meijer
- Biocentrum-DTU, Center for Microbial Biotechnology, building, 223, Søltofts Plads, Technical University of Denmark, 2800 Kgs, Lyngby, Denmark
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Kasuga T, Townsend JP, Tian C, Gilbert LB, Mannhaupt G, Taylor JW, Glass NL. Long-oligomer microarray profiling in Neurospora crassa reveals the transcriptional program underlying biochemical and physiological events of conidial germination. Nucleic Acids Res 2005; 33:6469-85. [PMID: 16287898 PMCID: PMC1283539 DOI: 10.1093/nar/gki953] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 09/22/2005] [Accepted: 10/19/2005] [Indexed: 01/26/2023] Open
Abstract
To test the inferences of spotted microarray technology against a biochemically well-studied process, we performed transcriptional profiling of conidial germination in the filamentous fungus, Neurospora crassa. We first constructed a 70 base oligomer microarray that assays 3366 predicted genes. To estimate the relative gene expression levels and changes in gene expression during conidial germination, we analyzed a circuit design of competitive hybridizations throughout a time course using a Bayesian analysis of gene expression level. Remarkable consistency of mRNA profiles with previously published northern data was observed. Genes were hierarchically clustered into groups with respect to their expression profiles over the time course of conidial germination. A functional classification database was employed to characterize the global picture of gene expression. Consensus motif searches identified a putative regulatory component associated with genes involved in ribosomal biogenesis. Our transcriptional profiling data correlate well with biochemical and physiological processes associated with conidial germination and will facilitate functional predictions of novel genes in N.crassa and other filamentous ascomycete species. Furthermore, our dataset on conidial germination allowed comparisons to transcriptional mechanisms associated with germination processes of diverse propagules, such as teliospores of the phytopathogenic fungus Ustilago maydis and spores of the social amoeba Dictyostelium discoideum.
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Affiliation(s)
- Takao Kasuga
- Department of Plant and Microbial Biology, University of CaliforniaBerkeley, CA 94720-3102, USA
| | - Jeffrey P. Townsend
- Department of Plant and Microbial Biology, University of CaliforniaBerkeley, CA 94720-3102, USA
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT 06269, USA
| | - Chaoguang Tian
- Department of Plant and Microbial Biology, University of CaliforniaBerkeley, CA 94720-3102, USA
| | - Luz B. Gilbert
- Department of Plant and Microbial Biology, University of CaliforniaBerkeley, CA 94720-3102, USA
| | - Gertrud Mannhaupt
- Institute for Bioinformatics (MIPS), GSF National Research Center for Environment and HealthD-85764 Neuherberg, Germany
| | - John W. Taylor
- Department of Plant and Microbial Biology, University of CaliforniaBerkeley, CA 94720-3102, USA
| | - N. Louise Glass
- Department of Plant and Microbial Biology, University of CaliforniaBerkeley, CA 94720-3102, USA
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Pokorný R, Vargovic P, Hölker U, Janssen M, Bend J, Hudecová D, Varecka L. Developmental changes in Trichoderma viride enzymes abundant in conidia and the light-induced conidiation signalling pathway. J Basic Microbiol 2005; 45:219-29. [PMID: 15900543 DOI: 10.1002/jobm.200410354] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The expression of glutamic acid decarboxylase gene and the laccase activity were measured during the development of surface-cultivated Trichoderma viride mycelia in order to examine their up-regulation by light. The results show that the changes in activity of GAD induced by light observed previously are caused by transcriptional regulation of gad gene expression in both submerged mycelia and aerial mycelia after photoinduction. The expression of tga gene encoding a T. viride G(alpha) protein was found not to be up-regulated by light and was also present in the non-conidiating mutant of T. viride suggesting that this protein is not involved in the regulation of conidiation in this fungus, or that it plays a role is in later stages of conidia development. The activity of laccase was also not light-inducible and may be related to the maturation of conidia.
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Affiliation(s)
- Richard Pokorný
- Department of Biochemistry and Microbiology, Slovak University of Technology, Radlinského 9, 81237-Bratislava, Slovakia
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21
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Panagiotou G, Villas-Bôas SG, Christakopoulos P, Nielsen J, Olsson L. Intracellular metabolite profiling of Fusarium oxysporum converting glucose to ethanol. J Biotechnol 2005; 115:425-34. [PMID: 15639104 DOI: 10.1016/j.jbiotec.2004.09.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Revised: 09/23/2004] [Accepted: 09/27/2004] [Indexed: 10/26/2022]
Abstract
The filamentous fungus Fusarium oxysporum is known for its ability to produce ethanol by simultaneous saccharification and fermentation (SSF) of cellulose. However, the conversion rate is low and significant amounts of acetic acid are produced as a by-product. In this study, the growth characteristics of F. oxysporum were evaluated in a minimal medium using glucose as the sole carbon source in aerobic, anaerobic and oxygen-limited batch cultivations. Under aerobic conditions the maximum specific growth rate was found to be 0.043 h(-1), and the highest ethanol yield (1.66 mol/mol) was found under anaerobic conditions. During the different phases of the cultivations, the intracellular profiles were determined under aerobic and anaerobic conditions. The profiles of the phosphorylated intermediates indicated that there was a high glycolytic flux at anaerobic growth conditions, characterized by high efflux of glyceraldehyde-3-phosphate (G3P) and fructose-6-phosphate (F6P) from the pentose phosphate pathway (PPP) to the Embden-Meyerhof-Parnas (EMP) pathway, resulting in the highest ethanol production under these conditions. The amino acid profile clearly suggests that the TCA cycle was primarily active under aerobic cultivation. On the other hand, the presence of high levels of gamma-amino-n-butyric acid (GABA) under anaerobic conditions suggests a functional GABA bypass and a possible block in the TCA cycle at these conditions.
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Affiliation(s)
- Gianni Panagiotou
- Center for Microbial Biotechnology, BioCentrum-DTU, Technical University of Denmark, Soltofts Plads, Building 223, 2800 Lyngby, Denmark
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22
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Pokorný R, Hudecová D, Burgstaller W, Varecka L. Changes in properties of glutamate transport in Trichoderma viride vegetative mycelia upon adaptation to glutamate as carbon source. FEMS Microbiol Lett 2004; 230:123-8. [PMID: 14734174 DOI: 10.1016/s0378-1097(03)00884-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The U-(14)C-labelled glutamate uptake was measured in both sucrose- and glutamate-grown mycelia of Trichoderma viride. The biomass yield was five-fold lower with glutamate as a sole carbon source. The rate of glutamate transport measured at a glutamate concentration of 1 mM remained unchanged in glutamate-grown mycelia whereas the properties of the glutamate transport were substantially changed compared to sucrose-grown mycelia. The glutamate uptake in both sucrose- and glutamate-grown mycelia was inhibited by an uncoupler (3,3',4',5-tetrachlorosalicylanilide) but the inhibitory efficiency was higher in the latter. The affinity of the permease to glutamate increased approximately five-fold in the glutamate-grown mycelia (about 76 microM compared to about 16 microM). The pH optimum for glutamate uptake was 4 in sucrose-grown mycelia but the glutamate-grown mycelia had two pH optima, one at pH 4 and the second between pH 6 and 7. The inhibition of glutamate uptake by other amino acids yielded different inhibitory patterns in the two mycelia under study. The glutamate uptake in mycelia of different ages also showed differences in both transport rate and temporal pattern. The results show that the growth of mycelia on glutamate led to the appearance of an additional permease with different properties and suggest that only this permease is operating in mycelia grown on glutamate.
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Affiliation(s)
- Richard Pokorný
- Department of Biochemistry and Microbiology, Slovak University of Technology, Bratislava, Slovak Republic
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23
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Abstract
The asexual spore, or conidium, is critical in the life cycle of many fungi because it is the primary means for dispersion and serves as a 'safe house' for the fungal genome in adverse environmental conditions. This review discusses the physiological process of germination, conidial adhesion and initiation of protein synthesis and also the regulatory pathways used to activate conidial germination. These include Ca(2+)/calmodulin-mediated signaling, the cyclic AMP/protein kinase A and the ras/mitogen-activated protein kinase pathways. Insights into the process of conidial germination will increase our understanding of the mechanisms of dormancy and sensing of environmental stimuli, and permit identification of novel therapeutic targets for the treatment of spore-borne fungal infections in plants and animals.
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Affiliation(s)
- N Osherov
- Division of Pathology and Laboratory Medicine, P.O. Box 54, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
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24
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Hao R, Schmit JC. Cloning of the gene for glutamate decarboxylase and its expression during conidiation in Neurospora crassa. Biochem J 1993; 293 ( Pt 3):735-8. [PMID: 8352739 PMCID: PMC1134427 DOI: 10.1042/bj2930735] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Neurospora crassa glutamate decarboxylase (GAD) is produced during conidiation and stored in dormant conidia. Polyclonal antibody was generated to GAD that had been purified to homogeneity. The anti-GAD antibody was specific for N. crassa GAD and inhibited GAD activity. The level of GAD protein decreased during conidial germination, indicating that GAD was degraded during this phase of development. The anti-GAD antibody was used to isolate a cDNA clone of GAD from a lambda ZAP cDNA expression library. Escherichia coli containing a plasmid with the cDNA insert produced GAD activity. The cDNA clone contained a 2.6 kbp insert and hybridized to a 2.6 kb mRNA species from conidiating cultures of N. crassa. GAD mRNA was not present in vegetative hyphae. In conidiating cultures, GAD mRNA was first detected when conidia began to appear. The level of GAD mRNA increased as conidiation progressed. This is the first example of the cloning of an enzyme that is regulated at the level of mRNA during the asexual developmental cycle of N. crassa.
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Affiliation(s)
- R Hao
- Southern Illinois University, Carbondale 62901
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26
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Sachs MS, Yanofsky C. Developmental expression of genes involved in conidiation and amino acid biosynthesis in Neurospora crassa. Dev Biol 1991; 148:117-28. [PMID: 1834495 DOI: 10.1016/0012-1606(91)90322-t] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The levels of transcripts for Neurospora crassa genes concerned with cellular and metabolic functions changed dramatically at different stages of asexual development. Transcripts for some conidiation-related (con) genes were present at high levels in conidiating cultures and in dormant conidia, but were absent or reduced during mycelial growth. Levels of some con transcripts increased transiently during conidial germination, while others disappeared. Transcripts for amino acid biosynthetic enzymes, ribosomal proteins, cytochrome oxidase subunits, histones, and other polypeptides important for cell growth were detected in newly formed conidia and were present at reduced levels in dormant conidia. Levels of these transcripts increased upon germination of wild-type conidia in minimal medium, reaching their highest levels during this stage or during the early phase of exponential growth. The increased transcription of amino acid biosynthetic genes observed during germination in minimal medium was not dependent on a functional cpc-1 gene. However, cpc-1, which encodes a DNA binding protein presumed to function as a transcriptional activator, was essential for increased expression of amino acid biosynthetic genes when amino acid starvation was imposed during germination or at any subsequent stage of mycelial growth.
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Affiliation(s)
- M S Sachs
- Department of Biological Sciences, Stanford University, California 94305
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27
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Hao R, Schmit JC. Purification and characterization of glutamate decarboxylase from Neurospora crassa conidia. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67765-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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28
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Jaworski A, Sedlaczek L, Dlugoński J. Transformation of steroids by fungal spores. Appl Microbiol Biotechnol 1984. [DOI: 10.1007/bf00270592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Brody S, Mikolajczyk SD, Fahey RC. Levels of sulfhydryls and disulfides in proteins from Neurospora crassa conidia and mycelia. J Bacteriol 1983; 156:703-9. [PMID: 6226648 PMCID: PMC217886 DOI: 10.1128/jb.156.2.703-709.1983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Proteins extracted with 6 M guanidine at 90 degrees C from conidia (asexual spores) of Neurospora crassa contained ca. 25% more total protein thiol and a fivefold-higher content of disulfide bonds than proteins extracted from mycelia, as determined by labeling with iodo[14C]acetic acid. The total thiol content was 88 mumol/g of protein in conidia and 70 mumol/g of protein in mycelia. The level of protein disulfide was 18.5 mumol/g of protein in conidia and 3.5 mumol/g of protein in mycelia, by the iodo[14C]acetic acid labeling method. Confirmatory results were obtained with 5'5-dithio-bis-2-nitrobenzoic acid titration of protein thiol groups in 1% sodium dodecyl sulfate as well as by amino acid analysis of cysteic acid derivatives. Buffer-extracted proteins from conidia, but not mycelia, were found to contain enriched levels of protein thiols and disulfides per gram of protein as compared with guanidine hydrochloride extracts. It was demonstrated that the high disulfide content of crude conidial extracts was not due to measurable levels of mixed disulfides formed between protein sulfhydryl groups and cysteine. During germination of the conidia, the high disulfide levels of the conidial proteins remained constant. These data suggest that, unlike the disulfides of glutathione, the bulk of conidial protein disulfides were not reduced, excreted, or extensively degraded during germination.
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Uptake and decar☐ylation of Krebs cycle-derived amino acids byPhycomyces blakesleeanus spores. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0147-5975(83)90044-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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32
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Diaz L, Salas J, Hardisson C. Intracellular pool ofStreptomycesspores: Amino acids, nucleosides, adenine nucleotide levels and energy charge. FEMS Microbiol Lett 1983. [DOI: 10.1111/j.1574-6968.1983.tb00545.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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33
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Guignard R, Brody S. Conidium formation and germination inNeurospora crassa: Glutamic acid metabolism. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0147-5975(83)90056-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Jaworski A, Sedlaczek L, Sasiak A, Dŀugoński J. Transformation of steroids by fungal spores. ACTA ACUST UNITED AC 1982. [DOI: 10.1007/bf00500728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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35
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Jaworski A, Sedlaczek L, Wilmańska D, Sasiak A, Strycharska A. Factors regulating the steroid 11-hydroxylation by non-germinating spores of Cunninghamella elegans (Lendner). ZEITSCHRIFT FUR ALLGEMEINE MIKROBIOLOGIE 1982; 22:327-33. [PMID: 7124000 DOI: 10.1002/jobm.3630220506] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In the presence of malate or citrate sporangiospores of C. elegans were able to hydroxylate cortexolone with a rate twofold exceeding that of the control, water suspended spores. Analysis of the intracellular nicotinamide coenzyme pools revealed an increased NADPH:(NADP+ + NADPH) ratio, indicating more effective NADPH-generating systems in malate- or citrate-stimulating spores. Swollen spores remaining in the pregermination state, retained higher cortexolone-hydroxylating activity in the absence of malate and citrate. In these spores degradation of endogenous alanine and glutamic acid was observed. Possible NADPH-generating systems in C. elegans sporangiospores were discussed.
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37
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Wertman KF, Paznokas JL. Effects of cyclic nucleotides upon the germination ofMucor racemosus sporangiospores. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0147-5975(81)90036-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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38
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Alberghina L, Sturani E. Control of growth and of the nuclear division cycle in Neurospora crassa. Microbiol Rev 1981; 45:99-122. [PMID: 6452573 PMCID: PMC281500 DOI: 10.1128/mr.45.1.99-122.1981] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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40
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Christensen RL, Schmit JC. Regulation and glutamic acid decarboxylase during Neurospora crassa conidial germination. J Bacteriol 1980; 144:983-90. [PMID: 6449504 PMCID: PMC294761 DOI: 10.1128/jb.144.3.983-990.1980] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Glutamic acid decarboxylase (GAD) from Neurospora crassa was assayed in dormant and germinating conidia that had been permeabilized by toluene and methanol. N. crassa conidia contained 10 times the GAD activity found in vegetativemycelia. During conidial germination, GAD activity rapidly decreased to low levels before germ tubes appeared. GAD activity in germinating conidia closely followed the decreasing rate of glutamic acid metabolism. Inhibiting protein synthesis partially blocked the decrease in GAD activity, but eliminating exogenous carbon sources did not alter the initial rate of decrease in this enzyme. However, when conidia were incubated for more than 3 h in distilled water, GAD activity began to increase and eventually reached levels comparable to those in dormant conidia. Either GAD was reversibly inactivated or this enzyme could be synthesized from endogenous storage compounds when conidia were incubated in distilled water. These results are consistent with the hypothesis that GAD is a developmentally regulated enzyme that is responsible for catalyzing the first step in the metabolism of the large pool of free glutamic acid during conidial germination.
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41
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42
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Hansberg W, Espín G, Palacios R, Sánchez F. Regulation of glutamine synthetase messenger ribonucleic acid in connidia of Neurospora crassa. Dev Biol 1979; 73:68-75. [PMID: 43270 DOI: 10.1016/0012-1606(79)90138-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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43
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Kubicek CP, Hampel W, Röhr M. Manganese deficiency leads to elevated amino acid pools in citric acid accumulating Aspergillus niger. Arch Microbiol 1979; 123:73-9. [PMID: 543776 DOI: 10.1007/bf00403504] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Free amino acid pools have been investigated in a citric acid accumulating strain of Aspergillus niger during batch growth under manganese sufficient and deficient conditions by means of an improved chromatographic method. Studies on the mycelial content of several nitrogenous compounds under manganese sufficient and deficient conditions showed that manganese deficiency resulted in lower amino acid pool sizes during trophophase and considerable accumulation during idiophase, and in a reduction of the protein and nucleic acid contents. Addition of cycloheximide to mycelia grown with sufficient manganese also caused an elevation of free amino acid pool sizes, thus indicating that impairment of protein synthesis by manganese deficiency is responsible for the observed rise in amino acid concentration. Furthermore it was observed that the manganese deficient mycelia excreted high amounts of all amino acids suggesting that manganese deficiency may also affect membrane permeability.
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44
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45
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Fahey RC, Mikolajczyk SD, Brody S. Correlation of enzymatic activity and thermal resistance with hydration state in ungerminated Neurospora conidia. J Bacteriol 1978; 135:868-75. [PMID: 151096 PMCID: PMC222458 DOI: 10.1128/jb.135.3.868-875.1978] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ungerminated Neurospora crassa conidia were incubated at 0, 50, and 100% relative humidity, giving rise to conidia in dry, quasi-dry, and wet hydration states, respectively. Metabolic activity was detected by monitoring levels of reduced glutathione (GSH), oxidized glutathione (GSSG), and the soluble-amino acid pools as a function of incubation time. Wet conidia (approximately 65% water content) exhibited significant metabolic activity as evidenced by: (i) reduction of GSSG to GSH, (ii) degradation of GSH, and (iii) changes in the pool sizes of certain amino acids. GSSG accumulated slowly in dry conidia (less than 5% water content) and more rapidly in quasi-dry conidia (approximately 13% water content), indicating that enzymatic reduction of GSSG is inactive in these states. Longevity and thermal resistance were high for dry conidia and low for wet conidia, but were not influenced by variation in GSSG content. The water content of conidia exhibited a hysteresis effect in that at a given relative humidity previously dried conidia attained a lower water content than freshly harvested conidia.
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46
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Rosenberg G, Pall ML. Cyclic AMP and cyclic GMP in germinating conidia of Neurospora crassa. Arch Microbiol 1978; 118:87-90. [PMID: 211974 DOI: 10.1007/bf00406079] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A new method for obtaining synchronous germination allowed accurate time-course studies of endogenous levels of cyclic adenosine 3',5'-monophosphate and cyclic guanosine 3',5'-phosphate in germinating conidia of Neurospora crassa. The levels of both cyclic nucleotides remained constant throughout germination, showing that they neither signal nor respond to any of the biochemical changes which are known to occur in the germination process. Conidal germination was approximately normal in three cr-1 mutants of Neurospora which have been shown to be deficient in adenylate cyclase activity. Cyclic AMP levels in the mycelia of cr-1 mutants were low, but surprisingly, the levels in conidia were normal.
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47
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Orlowski M, Sypherd PS. Regulation of macromolecular synthesis during hyphal germ tube emergence from Mucor racemosus sporangiospores. J Bacteriol 1978; 134:76-83. [PMID: 649573 PMCID: PMC222220 DOI: 10.1128/jb.134.1.76-83.1978] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Protein and RNA syntheses were examined during hyphal germ tube emergence from sporangiospores of a dimorphic phycomycete, Mucor racemosus. Both classes of macromolecules were synthesized immediately upon introduction of the dormant sporangiospores into nutrient medium. The specific rates of synthesis of both protein and RNA accelerated during initial germ tube emergence and reached a maximum when the emergence of new germ tubes ended. The specific rates of synthesis later decreased during further hyphal elongation. The distribution of ribosomes between active polysomes and monosomes and inactive subunits was determined by sucrose density gradient centrifugation, and the rate of amino acid addition to nascent polypeptide chains was calculated throughout the developmental sequence. The results showed that both the percentage of ribosomes active in protein synthesis and the velocity of ribosome movement along the mRNA were continuously adjusted throughout hyphal germ tube development. The free intracellular amino acid pools were measured throughout development. Alanine, glutamate, and aspartate were present at very high concentrations in the dormant spores but were rapidly depleted during hyphal germ tube emergence. The results of these studies are discussed in relation to hyphal germ tube development from yeast cells of Mucor and dormant spores of other fungal species.
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48
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49
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Mirkes PE. Role of the carbon source in the activation of ribonucleic acid synthesis during the germination of Neurospora crassa conidia. ACTA ACUST UNITED AC 1977. [DOI: 10.1016/s0147-5975(77)80002-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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50
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Hashimoto T, Blumenthal HJ. Factors affecting germination of Trichophyton mentagrophytes arthrospores. Infect Immun 1977; 18:479-86. [PMID: 21851 PMCID: PMC421257 DOI: 10.1128/iai.18.2.479-486.1977] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nutritional and environmental factors affecting germination of Trichophyton mentagrophytes arthrospores were investigated. Germination of dormant arthrospores occurred only in rich complex media such as Sabouraud dextrose broth or vitamin-free Casamino Acids. However, once activated, arthrospores were able to germinate under wide ranges of pH (5.5 to 8.0, optimal 6.5) and temperature (20 to 39 degrees C, optimal 37 degrees C) in the presence of certain single amino acids or oligopeptides known to be present in the human cutaneous tissues. Dormant arthrospores could be activated by incubation in distilled water at 25 degrees C for 24 h or by brief exposure to sublethal doses of heat (45 degrees C for 10 to 20 min). Approximately 20% of activated arthrospores underwent spontaneous germination at 37 degrees C during an additional 18 h of incubation in distilled water. All monosaccharides, purines, pyrimidines, and nucleosides tested failed to induce germination of T. mentagrophytes arthrospores. Germination rate was affected by the concentration of germination inducers as well as that of arthrospores. The germination process of T. mentagrophytes arthrospores was found to be oxygen dependent and was relatively tolerant to NaCl, clotrimazole, cycloheximide, griseofulvin, and tolnaftate.
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