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FEMS Yeast Research Dec 2008The kinetic parameters of the 10 glycolytic enzymes and glycolytic fluxes were determined for the first time in Ustilago maydis. Enzyme activities in yeast grown in...
The kinetic parameters of the 10 glycolytic enzymes and glycolytic fluxes were determined for the first time in Ustilago maydis. Enzyme activities in yeast grown in minimal medium and harvested in the stationary stage were twofold higher than those from yeast grown in rich medium. In contrast, in yeast harvested in the exponential stage, the enzyme activities were higher in cells grown in rich medium. Phosphofructokinase activity was the lowest in the four culture conditions analyzed, suggesting that this enzyme is a flux-controlling step in U. maydis glycolysis. The V(max) and K(m) values of hexokinase and pyruvate kinase were similar under all conditions. The results revealed that U. maydis aldolase belongs to the class II type of metalo-aldolases. 3-Phosphoglycerate mutase (PGAM) activity was 2,3-bisphosphoglycerate cofactor independent, which contrasted with the cofactor dependency predicted by the amino acid sequence alignment analysis. Pyruvate was secreted by U. maydis yeast in the presence and absence of external glucose. The glycolytic enzyme activities in the U. maydis mycelial form were similar to those found in yeast, except for one order of magnitude higher phosphofructokinase and PGAM activities, thus suggesting differences in the glycolysis regulatory mechanisms between the two cellular forms.
Topics: Culture Media; Fructose-Bisphosphate Aldolase; Fungal Proteins; Gene Expression Regulation, Fungal; Glycolysis; Hexokinase; Kinetics; Mycelium; Phosphofructokinases; Phosphoglycerate Mutase; Pyruvate Kinase; Ustilago
PubMed: 18803552
DOI: 10.1111/j.1567-1364.2008.00437.x -
Microbiology and Molecular Biology... Sep 2023This paper addresses the stability of mycelial growth in fungi and differences between ascomycetes and basidiomycetes. Starting with general evolutionary theories of... (Review)
Review
This paper addresses the stability of mycelial growth in fungi and differences between ascomycetes and basidiomycetes. Starting with general evolutionary theories of multicellularity and the role of sex, we then discuss individuality in fungi. Recent research has demonstrated the deleterious consequences of nucleus-level selection in fungal mycelia, favoring cheaters with a nucleus-level benefit during spore formation but a negative effect on mycelium-level fitness. Cheaters appear to generally be loss-of-fusion (LOF) mutants, with a higher propensity to form aerial hyphae developing into asexual spores. Since LOF mutants rely on heterokaryosis with wild-type nuclei, we argue that regular single-spore bottlenecks can efficiently select against such cheater mutants. We then zoom in on ecological differences between ascomycetes being typically fast-growing but short-lived with frequent asexual-spore bottlenecks and basidiomycetes being generally slow-growing but long-lived and usually without asexual-spore bottlenecks. We argue that these life history differences have coevolved with stricter nuclear quality checks in basidiomycetes. Specifically, we propose a new function for clamp connections, structures formed during the sexual stage in ascomycetes and basidiomycetes but during somatic growth only in basidiomycete dikaryons. During dikaryon cell division, the two haploid nuclei temporarily enter a monokaryotic phase, by alternatingly entering a retrograde-growing clamp cell, which subsequently fuses with the subapical cell to recover the dikaryotic cell. We hypothesize that clamp connections act as screening devices for nuclear quality, with both nuclei continuously testing each other for fusion ability, a test that LOF mutants will fail. By linking differences in longevity of the mycelial phase to ecology and stringency of nuclear quality checks, we propose that mycelia have a constant and low lifetime cheating risk, irrespective of their size and longevity.
Topics: Mycelium; Hyphae; Fungi
PubMed: 37409939
DOI: 10.1128/mmbr.00022-21 -
Current Microbiology Apr 2011Autolysis is an important physiological process found in fungal cultivation. However, there is hitherto no report on the autolysis of Pleurotus tuber-regium. We have...
Autolysis is an important physiological process found in fungal cultivation. However, there is hitherto no report on the autolysis of Pleurotus tuber-regium. We have investigated the enzymes secreted by temperature-induced (40°C as treatment versus 10°C as control) autolysis of the mycelium of P. tuber-regium grown in submerged cultivation. A comparison between the intracellular proteins (inside the mycelium) and the extracellular proteins (in the culture medium) of the treatment and control by proteomic analysis involving 2D PAGE and MALDI-TOF-MS was made. Twenty-two up-regulated protein spots were detected and eight proteins were identified. They included proteasome which participates in the ubiquitin-proteasome pathway; β-1,3-glucanosyltransferase and tubulin which are involved in the renewal and repair of cell wall; protease and endoglucanase which promote the natural degradation of cell wall and cytoplasm; 14-3-3 protein which takes part in cell signal transduction; and two putative proteins presumably relate to the autolysis process. These identified proteins suggest partially the metabolic processes of the autolysis in the P. tuber-regium mycelium.
Topics: Electrophoresis, Gel, Two-Dimensional; Fungal Proteins; Gene Expression Regulation, Fungal; Molecular Sequence Data; Mycelium; Pleurotus; Proteomics; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Temperature
PubMed: 21161227
DOI: 10.1007/s00284-010-9838-4 -
Fungal Biology Feb 2020Lentinula edodes is a widely-produced mushroom in China that forms a brown film via pigment accumulation on mature mycelial surfaces to ensure high-quantity and...
Lentinula edodes is a widely-produced mushroom in China that forms a brown film via pigment accumulation on mature mycelial surfaces to ensure high-quantity and high-quality fruiting body formation. Here, ultraviolet-visible, infrared spectra, and elemental analyses predicted that the pigment in the brown film was melanin. Electron microscopy revealed the size, morphological characteristics, accumulation, and morphogenesis of electron-dense material, which were similar to those of melanin, as well as subcellular structural changes during brown film formation. The electron-dense material appeared as granules, vesicles, and polymers. The accumulation of electron-dense materials on the cell wall was followed plasmolysis, plasma membrane disruption, electron-dense material accumulation in the interstitial space, and gradual accumulation on the outer cell wall. Dolipore septa degradation and morphogenetic cell death occurred during browning. In the final stage of browning, the dolipore septum disappeared and the cell was nearly empty. This study provides a cytological foundation for evaluating the regulation of brown film formation in L. edodes.
Topics: Fruiting Bodies, Fungal; Fungal Proteins; Melanins; Microscopy, Electron, Transmission; Mycelium; Pigments, Biological; Shiitake Mushrooms; Spectrum Analysis
PubMed: 32008754
DOI: 10.1016/j.funbio.2019.12.008 -
Chemosphere Aug 2016The role of the aerial mycelium of the fungus Fusarium solani in the biodegradation of n-pentane was evaluated in a continuous fungal bioreactor (FB) to determine the...
The role of the aerial mycelium of the fungus Fusarium solani in the biodegradation of n-pentane was evaluated in a continuous fungal bioreactor (FB) to determine the contribution of the aerial (hyphae) and non-aerial (monolayer) fungal biomass. The experimental results showed that although the aerial biomass fraction represented only 25.9(±3)% on a dry weight basis, it was responsible for 71.6(±4)% of n-pentane removal. The FB attained a maximum elimination capacity (ECmax) of 680(±30) g m(-3) h(-1) in the presence of fungal hyphae (which supported an interfacial area of 5.5(±1.5) × 10(6) m(2) m(-3)). In addition, a mathematical model capable of describing n-pentane biodegradation by the filamentous fungus was also developed and validated against the experimental data. This model successfully predicted the influence of the aerial biomass fraction and its partition coefficient on the n-pentane removal, with EC decreasing from 680(±30) g m(-3) h(-1) to values of 200(±14) g m(-3) h(-1) when the dimensionless partition coefficient increased from 0.21(±0.09) with aerial biomass to 0.88(±0.06) without aerial biomass.
Topics: Biodegradation, Environmental; Biomass; Bioreactors; Fusarium; Hydrophobic and Hydrophilic Interactions; Models, Theoretical; Mycelium; Pentanes; Volatile Organic Compounds
PubMed: 27209557
DOI: 10.1016/j.chemosphere.2016.05.034 -
Journal of Dairy Science Oct 2015The growth characteristics of Phellinus linteus mycelium were assessed and compared under solid-state fermentation (SSF) and submerged liquid fermentation (SLF) systems...
The growth characteristics of Phellinus linteus mycelium were assessed and compared under solid-state fermentation (SSF) and submerged liquid fermentation (SLF) systems on whey permeate medium. Response surface methodology was used to investigate the growth rates of mycelia under various conditions of operating temperature (TO), initial pH, and substrate concentration ([S]). The optimal growth conditions of P. linteus mycelium were determined to be 26.1°C, pH 4.6, and 60.3g of lactose/L in the SSF system, and 29.0°C, pH 5.0, and 65.3g of lactose/L in the SLF system. The maximum growth rates were predicted to be 1.92 ± 0.01 mm/d in SSF and 192.1 ± 0.0mg/L per day in SLF. Random trials were conducted to experimentally validate the evaluated optimal conditions. The differences between the modeled and observed values were only 5.3% in the SSF system and 6.1% in the SLF system. Significant engineering factors differed between the fermentation techniques; TO was significant in both cultivation systems, whereas initial pH was significant in SSF but [S] was significant in SLF. Our findings can be used to guide the operation of the bioconversion process for cultivating P. linteus mycelium using whey permeate wastewater.
Topics: Basidiomycota; Fermentation; Mycelium; Waste Disposal, Fluid; Wastewater; Whey
PubMed: 26233453
DOI: 10.3168/jds.2015-9631 -
Bio Systems May 2021Oyster fungi Pleurotus djamor generate actin potential like spikes of electrical potential. The trains of spikes might manifest propagation of growing mycelium in a...
Oyster fungi Pleurotus djamor generate actin potential like spikes of electrical potential. The trains of spikes might manifest propagation of growing mycelium in a substrate, transportation of nutrients and metabolites and communication processes in the mycelium network. The spiking activity of the mycelium networks is highly variable compared to neural activity and therefore can not be analysed by standard tools from neuroscience. We propose original techniques for detecting and classifying the spiking activity of fungi. Using these techniques, we analyse the information-theoretic complexity of the fungal electrical activity. The results can pave ways for future research on sensorial fusion and decision making of fungi.
Topics: Action Potentials; Mycelium; Pleurotus
PubMed: 33577948
DOI: 10.1016/j.biosystems.2021.104373 -
Microbiology (Reading, England) Nov 2005Development-associated cell-death processes were investigated in detail during the growth and differentiation of Streptomyces antibioticus ATCC 11891 on confluent...
Development-associated cell-death processes were investigated in detail during the growth and differentiation of Streptomyces antibioticus ATCC 11891 on confluent surface cultures, by using fluorescent viability probes, membrane and activity fluorescence indicators, and electron microscopy analysis. A previously unsuspected complexity was revealed, namely the presence of a very young compartmentalized mycelium that dies following an orderly pattern, leaving alternating live and dead segments in the same hypha. This death round is followed by the growth of a second mycelium which develops rapidly from the live segments of the first mycelium and dies massively in a second death round, which extends over the phases of aerial mycelium formation and sporulation.
Topics: Cell Membrane Permeability; Culture Media; Microscopy, Confocal; Microscopy, Fluorescence; Mycelium; Organic Chemicals; Propidium; Streptomyces antibioticus
PubMed: 16272390
DOI: 10.1099/mic.0.28045-0 -
PloS One 2015In wheat straw based composting, enabling growth of Agaricus bisporus mushrooms, it is unknown to which extent the carbohydrate-lignin matrix changes and how much is...
In wheat straw based composting, enabling growth of Agaricus bisporus mushrooms, it is unknown to which extent the carbohydrate-lignin matrix changes and how much is metabolized. In this paper we report yields and remaining structures of the major components. During the Phase II of composting 50% of both xylan and cellulose were metabolized by microbial activity, while lignin structures were unaltered. During A. bisporus' mycelium growth (Phase III) carbohydrates were only slightly consumed and xylan was found to be partially degraded. At the same time, lignin was metabolized for 45% based on pyrolysis GC/MS. Remaining lignin was found to be modified by an increase in the ratio of syringyl (S) to guaiacyl (G) units from 0.5 to 0.7 during mycelium growth, while fewer decorations on the phenolic skeleton of both S and G units remained.
Topics: Agaricus; Carbohydrate Metabolism; Lignin; Mycelium; Plant Proteins; Soil; Soil Microbiology; Triticum
PubMed: 26436656
DOI: 10.1371/journal.pone.0138909 -
Microbiology (Reading, England) Sep 2016The saprophytic actinobacterium Streptomyces coelicolor A3(2) requires oxygen for filamentous growth. Surprisingly, the bacterium also synthesizes three active...
The saprophytic actinobacterium Streptomyces coelicolor A3(2) requires oxygen for filamentous growth. Surprisingly, the bacterium also synthesizes three active respiratory nitrate reductases (Nar), which are believed to contribute to survival, or general fitness, of the bacterium in soil when oxygen becomes limiting. In this study, we analysed Nar3 and showed that activity of the enzyme is restricted to stationary-phase mycelium of S. coelicolor. Phosphate limitation was shown to be necessary for induction of enzyme synthesis. Nar3 synthesis was inhibited by inclusion of 20 mM phosphate in a defined 'switch assay' in which highly dispersed mycelium from exponentially growing cultures was shifted to neutral MOPS-glucose buffer to induce Nar3 synthesis and activity. Quantitative assessment of nar3 transcripts revealed a 30-fold induction of gene expression in stationary-phase mycelium. Transcript levels in stationary-phase mycelium incubated with phosphate were reduced by a little more than twofold, suggesting that the negative influence of phosphate on Nar3 synthesis was mainly at the post-transcriptional level. Furthermore, it was demonstrated that oxygen limitation was necessary to induce high levels of Nar3 activity. However, an abrupt shift from aerobic to anaerobic conditions prevented appearance of Nar3 activity. This suggests that the bacterium regulates Nar3 synthesis in response to the energy status of the mycelium. Nitrate had little impact on regulation of the Nar3 level. Together, these data identify Nar3 as a stationary-phase nitrate reductase in S. coelicolor and demonstrate that enzyme synthesis is induced in response to both phosphate limitation and hypoxia.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Developmental; Gene Expression Regulation, Enzymologic; Mycelium; Nitrate Reductase; Oxygen; Phosphates; Streptomyces coelicolor
PubMed: 27499000
DOI: 10.1099/mic.0.000349