The Experts below are selected from a list of 603 Experts worldwide ranked by ideXlab platform
Hirofumi Hirai - One of the best experts on this subject based on the ideXlab platform.
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Self-fusion and fusion cell isolation of transformants derived from white rot fungus Phanerochaete sordida YK-624 by simple visual method.
Journal of bioscience and bioengineering, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Tomoki Sumiya, Ojiro Kondo, Hirofumi HiraiAbstract:In order to develop a simple method for crossing two transformants, we first attempted to elucidate the fusion type (self-compatibility or -incompatible) of Phanerochaete sordida YK-624. Two transformants expressing green or red fluorescent protein derived from an auxotrophic mutant were constructed. Each recombinant protein fluoresced by expression as a fused protein with glyceraldehyde-3-phosphate dehydrogenase. On co-culture of both transformants, a number of sequential hyphal cells emitting dual fluorescence were formed at the contact areas of both hyphae. Some of the single cells isolated as protoplasts and chlamydospore from the co-cultures also expressed these fluorescent proteins. These results suggest that P. sordida YK-624 possesses a self-compatible fusion system. In addition, transformant strains with different fluorescence derived from this fungus can readily undergo self-fusion and nuclear interchange events by confrontational and mixed cultivation, and we developed a simple method that allows fused cells to be isolated as chlamydospores.
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Biotransformation and detoxification of the neonicotinoid insecticides nitenpyram and dinotefuran by Phanerochaete sordida YK-624
Environmental pollution (Barking Essex : 1987), 2019Co-Authors: Jianqiao Wang, Toshio Mori, Hirokazu Kawagishi, Tanaka Yusuke, Haruka Ohno, Jianbo Jia, Tangfu Xiao, Bing Yan, Hirofumi HiraiAbstract:Abstract Neonicotinoid insecticides have been widely used throughout the world over the last two decades. In the present study, we investigated the degradation of neonicotinoid insecticides nitenpyram (NIT) and dinotefuran (DIN) by the white-rot fungus Phanerochaete sordida YK-624. While NIT was completely degraded by P. sordida YK-624 under ligninolytic conditions, only a 20% decrease was observed under nonligninolytic conditions. On the other hand, P. sordida YK-624 degraded 31% of DIN under ligninolytic conditions after a 20-day incubation, while it did not degrade DIN under nonligninolytic conditions. We found that cytochromes P450 played a key role in the biotransformation of NIT and DIN by P. sordida YK-624. A novel NIT metabolite (E)-N-((6-chloropyridin-3-yl)methyl)-N-ethyl-N′-hydroxy acetimidamide (CPMHA) and a novel DIN metabolite N-((4aS,7aS,E)-1-methylhexahydrofuro[2,3-d]pyrimidin-2(1H)-ylidene)nitramide (PHPF) were identified in this study. In addition, to evaluate neurotoxicity, the effects of NIT, DIN and their metabolites on the viability of human neuroblastoma cells SH-SY5Y were determined. PHPF showed higher neurological toxicity than DIN, whereas the metabolite of NIT, CPMHA, showed no toxic effect. Our results indicated that the neurological toxicity of NIT could be effectively removed by P. sordida YK-624.
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Effect on growth, sugar consumption, and aerobic ethanol fermentation of homologous expression of the sugar transporter gene Pshxt1 in the white rot fungus Phanerochaete sordida YK-624.
Journal of bioscience and bioengineering, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Ojiro Kondo, Akane Masuda, Hirofumi HiraiAbstract:Major facilitator superfamily (MFS) transporters are found in all organisms. Although numerous studies have examined the functions of yeast and mold MFS transporters in terms of sugar affinity and metabolic regulation, no functional analyses of MFS sugar transporters in white rot fungi have been reported. This study identified an MFS sugar transporter gene (Pshxt1) of the white rot fungus Phanerochaete sordida YK-624 expressed in liquid culture containing low concentrations of nitrogen source. Homologous expression of Pshxt1 dramatically increased the rates of glucose, fructose, mannose, and xylose consumption. Galactose consumption increased slightly but significantly. These data suggest that Pshxt1 has broad affinity for monosaccharides. In contrast, a transformant homologously expressing Pshxt1 consumed glucose in preference to xylose in wood enzymatic-digestion liquor and liquid culture. Additionally, homologous expression of Pshxt1 improved mycelial growth, aerobic ethanol production, and simultaneous aerobic saccharification and fermentation efficiency, whereas secretion of the ligninolytic enzyme manganese peroxidase was clearly decreased in the presence of glucose by Pshxt1 expression. These results suggest that Pshxt1 is involved in the repression of ligninolytic enzyme activity via carbon catabolite repression at sufficiently high glucose concentrations for activation of primary metabolism.
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Effects of Glucose Concentration on Ethanol Fermentation of White-Rot Fungus Phanerochaete sordida YK-624 Under Aerobic Conditions
Current Microbiology, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Ojiro Kondo, Hirofumi HiraiAbstract:White-rot fungi are microorganisms capable of ethanol fermentation; however, the specific conditions activating ethanol fermentation are unclear in contrast to fermentation by yeasts. In this study, we investigated the conditions favoring ethanol fermentation by the white-rot fungus Phanerochaete sordida YK-624, which is able to produce ethanol from woody material. In aerobic stationary cultivation with various concentrations of glucose (0.8–33 g/l), the fungus produced ethanol in media containing an initial glucose concentration of 2.8 g/l or higher. The amount of glucose consumption, mycelial weight, and ethanol production on the second day of culture increased in a concentration-dependent manner at low glucose concentrations; however, these were saturated at high concentrations. Biomass yields (growth/glucose consumption) were decreased until the initial glucose concentration increased to 6.0 g/l, after which the biomass yields showed constant values at higher concentrations (12–33 g/l). On the other hand, ethanol yields increased with decreasing biomass yields. In short shaking cultivation using mycelial suspension, trace amounts of instantaneous aerobic ethanol production were observed with 1.1 and 2.1 g/l glucose, but the relative gene expression levels of key enzymes at the pyruvate branch point showed no significant differences between ethanol production and non-production conditions. From these experimental results, it appears that the white-rot fungus P. sordida YK-624 produces ethanol due to overflow in sugar metabolism under aerobic conditions, although P. sordida YK-624 prioritizes glucose utilization for respiratory growth.
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Functional characterization of the manganese transporter smf2 homologue gene, PsMnt, of Phanerochaete sordida YK-624 via homologous overexpression.
FEMS microbiology letters, 2018Co-Authors: Toshio Mori, Hirokazu Kawagishi, Yuki Nagai, Hirofumi HiraiAbstract:A homologue gene of the yeast natural resistance-associated macrophage protein (Nramp) family transporter smf2 was identified in the white-rot fungus Phanerochaete sordida YK-624. Relative expression levels of the homologue, designated PsMnt, were roughly equivalent in cultures containing 0 to 1000 μM Mn(II), a concentration non-toxic to the fungus. In the PsMnt-overexpressing mutant, cellular Mn accumulation and manganese peroxidase (MnP) activity increased significantly in 4-day cultures containing 10 μM MnSO4. Compared with the wild-type strain, MnP activity in the overexpressing mutants was higher at lower Mn concentrations (specifically 10-15 times higher). These results suggest that PsMnt is a high-affinity Mn transporter involved in cellular Mn accumulation under Mn-deficient conditions. This is the first report of an smf2 homologue in wood rot fungi.
Hirokazu Kawagishi - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomics analysis reveals the high biodegradation efficiency of white-rot fungus Phanerochaete sordida YK-624 on native lignin
2020Co-Authors: Jianqiao Wang, Toshio Mori, Hirokazu Kawagishi, Tomohiro Suzuki, Hideo Dohra, Hirai HirofumiAbstract:Abstract Background Lignocellulosic biomass is an organic matrix composed of cellulose, hemicellulose, and lignin. In nature, lignin degradation by basidiomycetes is the key step in lignocellulose decay. The white-rot fungus Phanerochaete sordida YK-624 (YK-624) has been extensively studied due to its high lignin degradation ability. In our previous study, it was demonstrated that YK-624 can secrete lignin peroxidase and manganese peroxidase for lignin degradation. However, the underlying mechanism for lignin degradation by YK-624 remains unknown.Results Here, we analyzed YK-624 gene expression following growth under ligninolytic and nonligninolytic conditions and compared the differentially expressed genes in YK-624 to those in the model white-rot fungus P. chrysosporium by next-generation sequencing. More ligninolytic enzymes and lignin-degrading auxiliary enzymes were upregulated in YK-624. This might explain the high degradation efficiency of YK-624. In addition, the genes involved in energy metabolism pathways, such as the TCA cycle, oxidative phosphorylation, lipid metabolism, carbon metabolism and glycolysis, were upregulated under ligninolytic conditions in YK-624.Conclusions In the present study, the first differential gene expression analysis of YK-624 under ligninolytic and nonligninolytic conditions was reported. The results obtained in this study indicated that YK-624 produces more energy- and lignin-degrading enzymes for more efficient lignin biodegradation.
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Self-fusion and fusion cell isolation of transformants derived from white rot fungus Phanerochaete sordida YK-624 by simple visual method.
Journal of bioscience and bioengineering, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Tomoki Sumiya, Ojiro Kondo, Hirofumi HiraiAbstract:In order to develop a simple method for crossing two transformants, we first attempted to elucidate the fusion type (self-compatibility or -incompatible) of Phanerochaete sordida YK-624. Two transformants expressing green or red fluorescent protein derived from an auxotrophic mutant were constructed. Each recombinant protein fluoresced by expression as a fused protein with glyceraldehyde-3-phosphate dehydrogenase. On co-culture of both transformants, a number of sequential hyphal cells emitting dual fluorescence were formed at the contact areas of both hyphae. Some of the single cells isolated as protoplasts and chlamydospore from the co-cultures also expressed these fluorescent proteins. These results suggest that P. sordida YK-624 possesses a self-compatible fusion system. In addition, transformant strains with different fluorescence derived from this fungus can readily undergo self-fusion and nuclear interchange events by confrontational and mixed cultivation, and we developed a simple method that allows fused cells to be isolated as chlamydospores.
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Biotransformation and detoxification of the neonicotinoid insecticides nitenpyram and dinotefuran by Phanerochaete sordida YK-624
Environmental pollution (Barking Essex : 1987), 2019Co-Authors: Jianqiao Wang, Toshio Mori, Hirokazu Kawagishi, Tanaka Yusuke, Haruka Ohno, Jianbo Jia, Tangfu Xiao, Bing Yan, Hirofumi HiraiAbstract:Abstract Neonicotinoid insecticides have been widely used throughout the world over the last two decades. In the present study, we investigated the degradation of neonicotinoid insecticides nitenpyram (NIT) and dinotefuran (DIN) by the white-rot fungus Phanerochaete sordida YK-624. While NIT was completely degraded by P. sordida YK-624 under ligninolytic conditions, only a 20% decrease was observed under nonligninolytic conditions. On the other hand, P. sordida YK-624 degraded 31% of DIN under ligninolytic conditions after a 20-day incubation, while it did not degrade DIN under nonligninolytic conditions. We found that cytochromes P450 played a key role in the biotransformation of NIT and DIN by P. sordida YK-624. A novel NIT metabolite (E)-N-((6-chloropyridin-3-yl)methyl)-N-ethyl-N′-hydroxy acetimidamide (CPMHA) and a novel DIN metabolite N-((4aS,7aS,E)-1-methylhexahydrofuro[2,3-d]pyrimidin-2(1H)-ylidene)nitramide (PHPF) were identified in this study. In addition, to evaluate neurotoxicity, the effects of NIT, DIN and their metabolites on the viability of human neuroblastoma cells SH-SY5Y were determined. PHPF showed higher neurological toxicity than DIN, whereas the metabolite of NIT, CPMHA, showed no toxic effect. Our results indicated that the neurological toxicity of NIT could be effectively removed by P. sordida YK-624.
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Effect on growth, sugar consumption, and aerobic ethanol fermentation of homologous expression of the sugar transporter gene Pshxt1 in the white rot fungus Phanerochaete sordida YK-624.
Journal of bioscience and bioengineering, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Ojiro Kondo, Akane Masuda, Hirofumi HiraiAbstract:Major facilitator superfamily (MFS) transporters are found in all organisms. Although numerous studies have examined the functions of yeast and mold MFS transporters in terms of sugar affinity and metabolic regulation, no functional analyses of MFS sugar transporters in white rot fungi have been reported. This study identified an MFS sugar transporter gene (Pshxt1) of the white rot fungus Phanerochaete sordida YK-624 expressed in liquid culture containing low concentrations of nitrogen source. Homologous expression of Pshxt1 dramatically increased the rates of glucose, fructose, mannose, and xylose consumption. Galactose consumption increased slightly but significantly. These data suggest that Pshxt1 has broad affinity for monosaccharides. In contrast, a transformant homologously expressing Pshxt1 consumed glucose in preference to xylose in wood enzymatic-digestion liquor and liquid culture. Additionally, homologous expression of Pshxt1 improved mycelial growth, aerobic ethanol production, and simultaneous aerobic saccharification and fermentation efficiency, whereas secretion of the ligninolytic enzyme manganese peroxidase was clearly decreased in the presence of glucose by Pshxt1 expression. These results suggest that Pshxt1 is involved in the repression of ligninolytic enzyme activity via carbon catabolite repression at sufficiently high glucose concentrations for activation of primary metabolism.
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Effects of Glucose Concentration on Ethanol Fermentation of White-Rot Fungus Phanerochaete sordida YK-624 Under Aerobic Conditions
Current Microbiology, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Ojiro Kondo, Hirofumi HiraiAbstract:White-rot fungi are microorganisms capable of ethanol fermentation; however, the specific conditions activating ethanol fermentation are unclear in contrast to fermentation by yeasts. In this study, we investigated the conditions favoring ethanol fermentation by the white-rot fungus Phanerochaete sordida YK-624, which is able to produce ethanol from woody material. In aerobic stationary cultivation with various concentrations of glucose (0.8–33 g/l), the fungus produced ethanol in media containing an initial glucose concentration of 2.8 g/l or higher. The amount of glucose consumption, mycelial weight, and ethanol production on the second day of culture increased in a concentration-dependent manner at low glucose concentrations; however, these were saturated at high concentrations. Biomass yields (growth/glucose consumption) were decreased until the initial glucose concentration increased to 6.0 g/l, after which the biomass yields showed constant values at higher concentrations (12–33 g/l). On the other hand, ethanol yields increased with decreasing biomass yields. In short shaking cultivation using mycelial suspension, trace amounts of instantaneous aerobic ethanol production were observed with 1.1 and 2.1 g/l glucose, but the relative gene expression levels of key enzymes at the pyruvate branch point showed no significant differences between ethanol production and non-production conditions. From these experimental results, it appears that the white-rot fungus P. sordida YK-624 produces ethanol due to overflow in sugar metabolism under aerobic conditions, although P. sordida YK-624 prioritizes glucose utilization for respiratory growth.
Tomoaki Nishida - One of the best experts on this subject based on the ideXlab platform.
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Removal of diclofenac and mefenamic acid by the white rot fungus Phanerochaete sordida YK-624 and identification of their metabolites after fungal transformation
Biodegradation, 2010Co-Authors: Takayuki Hata, Shingo Kawai, Hideo Okamura, Tomoaki NishidaAbstract:The non-steroidal anti-inflammatory drugs diclofenac (DCF) and mefenamic acid (MFA) were treated with the white rot fungus Phanerochaete sordida YK-624. DCF completely disappeared and MFA decreased by about 90% after 6 days of treatment. It was also confirmed that the fungus almost completely removed the acute lethal toxicity of DCF and MFA towards the freshwater crustacean Thamnocephalus platyurus after 6 days of treatment. Mass spectrometric and ^1H nuclear magnetic resonance analyses demonstrated that two mono-hydroxylated DCFs (4′-hydroxydiclofenac and 5-hydroxydiclofenac) and one di-hydroxylated DCF (4′,5-dihydroxydiclofenac) were formed via fungal transformation. The four metabolites of MFA were identified as 3′-hydroxymethylmefenamic acid (mono-hydroxylated MFA), 3′-hydroxymethyl-5-hydroxymefenamic acid (di-hydroxylated MFA), 3′-hydroxymethyl-6′-hydroxymefenamic acid (di-hydroxylated MFA) and 3′-carboxymefenamic acid. These results suggest that hydroxylation catalyzed by cytochrome P450 (CYP) in P. sordida YK-624 may be involved in the elimination and detoxification of DCF and MFA. This notion was further supported by the fact that smaller decreases in DCF and MFA were observed in cultures of P. sordida YK-624 incubated with 1-aminobenzotriazole, a known inhibitor of CYP.
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Cloning and Homologous Expression of Novel Lignin Peroxidase Genes in the White-Rot Fungus Phanerochaete sordida YK-624
Bioscience biotechnology and biochemistry, 2009Co-Authors: Tatsuki Sugiura, Hirokazu Kawagishi, Tomoaki Nishida, Kenji Yamagishi, Toshiyuki Kimura, Hirofumi HiraiAbstract:Two genes, encoding YK-LiP1 and YK-LiP2, were cloned from the white-rot fungus Phanerochaete sordida YK-624, and a homologous expression system for the gene was constructed. Two full-length cDNAs (ylpA and ylpB) were isolated by degenerate RT-PCR and RACE-PCR. The results of N-terminal amino acid sequence analysis of native YK-LiP1 and YK-LiP2 showed that ylpA and ylpB coded for YK-LiP2 and YK-LiP1 respectively. The promoter of glyceraldehyde-3-phosphate dehydrogenase cloned from P. sordida YK-624 (PsGPD) was used to drive the expression of ylpA. Expression vector pGPD-g-ylpA was transformed into a P. sordida YK-624 uracil auxotrophic mutant, UV-64. The YlpA protein was secreted in active form by the transformants after 4 d of growth in a medium containing an excessive nitrogen source, whereas endogenous YK-LiP1 and YK-LiP2 were not produced. The physical and catalytic properties of the purified YlpA protein were very similar to those of YK-LiP2. These results suggest that homologous expression of recombinant YK-LiP2 was successful.
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Removal of estrogenic activity of 4-tert-octylphenol by ligninolytic enzymes from white rot fungi
Environmental toxicology, 2007Co-Authors: Yuuki Tamagawa, Hirofumi Hirai, Shingo Kawai, Tomoaki NishidaAbstract:4-tert-Octylphenol (4-t-OP) was treated with the white rot fungus Phanerochaete sordida YK-624 under ligninolytic condition with low-nitrogen and high-carbon culture medium. 4-t-OP completely disappeared after 5 days of treatment and the activities of ligninolytic enzymes, laccase and manganese peroxidase (MnP), were detected during this period, thus suggesting that the disappearance of 4-t-OP is related to these extracellular enzymes. Therefore, 4-t-OP was treated with laccase and MnP prepared from white rot fungi cultures. HPLC analysis demonstrated that 4-t-OP completely disappeared in the reaction mixture after 1 h of treatment with either laccase or MnP. Using the yeast two-hybrid assay system, it was also confirmed that laccase and MnP substantially removed the estrogenic activity of 4-t-OP after 1 and 2 h of treatment, respectively. These results strongly demonstrate that ligninolytic enzymes are effective in removing the estrogenic activity of 4-t-OP.
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Removal of estrogenic activity of natural steroidal hormone estrone by ligninolytic enzymes from white rot fungi
Chemosphere, 2006Co-Authors: Yuuki Tamagawa, Hirofumi Hirai, Shingo Kawai, Ryoko Yamaki, Tomoaki NishidaAbstract:Natural steroidal hormone estrone (E1) was treated with the white rot fungus Phanerochaete sordida YK-624 under ligninolytic condition with low-nitrogen and high-carbon culture medium. E1 decreased by 98% after 5 d of treatment and the activities of ligninolytic enzymes, manganese peroxidase (MnP) and laccase, were detected during treatment, which suggested that the disappearance of E1 is related to ligninolytic enzymes produced extracellularly by white rot fungus. Therefore, E1 was treated with MnP and laccase prepared from the culture of white rot fungi. HPLC analysis demonstrated that E1 disappeared completely in the reaction mixture after 1 h of treatment with either MnP or laccase. Using the yeast two-hybrid assay system, it was also confirmed that both enzymatic treatments completely removed the estrogenic activity of E1 after 2 h. These results strongly suggest that ligninolytic enzymes are effective in removing the estrogenic activity of E1.
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Characteristics of novel lignin peroxidases produced by white-rot fungus Phanerochaete sordida YK-624
FEMS microbiology letters, 2005Co-Authors: Hirofumi Hirai, Mutsumi Sugiura, Shingo Kawai, Tomoaki NishidaAbstract:We characterized a lignin peroxidase (YK-LiP2) isolated from shaking culture inoculated with the white-rot fungus Phanerochaete sordida YK-624. The YK-LiP2 enzyme was identified and purified to homogeneity by anion-exchange chromatography and gel permeation chromatography. The molecular weight of YK-LiP2 was approximately 45 kDa, and its absorption spectrum was almost the same as that of the LiP (Pc-LiP) from P. chrysosporium. Steady-state kinetics of veratryl alcohol (VA) oxidation by YK-LiP2 revealed an ordered bi-bi ping-pong mechanism, although the Pc-LiP oxidation of ferrocytochrome c obeys peroxidase ping-pong kinetics rather than ordered bi-bi ping-pong kinetics. Degradation of dimeric lignin model compounds by YK-LiP2 was more effective than that by Pc-LiP. Moreover, YK-LiP2 and YK-LiP1, which was previously isolated from static culture inoculated with P. sordida YK-624, oxidized VA under a higher concentration of hydrogen peroxide (>2.5 mM) although Pc-LiP could not oxidize VA in the presence of 2.5 mM hydrogen peroxide.
Toshio Mori - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomics analysis reveals the high biodegradation efficiency of white-rot fungus Phanerochaete sordida YK-624 on native lignin
2020Co-Authors: Jianqiao Wang, Toshio Mori, Hirokazu Kawagishi, Tomohiro Suzuki, Hideo Dohra, Hirai HirofumiAbstract:Abstract Background Lignocellulosic biomass is an organic matrix composed of cellulose, hemicellulose, and lignin. In nature, lignin degradation by basidiomycetes is the key step in lignocellulose decay. The white-rot fungus Phanerochaete sordida YK-624 (YK-624) has been extensively studied due to its high lignin degradation ability. In our previous study, it was demonstrated that YK-624 can secrete lignin peroxidase and manganese peroxidase for lignin degradation. However, the underlying mechanism for lignin degradation by YK-624 remains unknown.Results Here, we analyzed YK-624 gene expression following growth under ligninolytic and nonligninolytic conditions and compared the differentially expressed genes in YK-624 to those in the model white-rot fungus P. chrysosporium by next-generation sequencing. More ligninolytic enzymes and lignin-degrading auxiliary enzymes were upregulated in YK-624. This might explain the high degradation efficiency of YK-624. In addition, the genes involved in energy metabolism pathways, such as the TCA cycle, oxidative phosphorylation, lipid metabolism, carbon metabolism and glycolysis, were upregulated under ligninolytic conditions in YK-624.Conclusions In the present study, the first differential gene expression analysis of YK-624 under ligninolytic and nonligninolytic conditions was reported. The results obtained in this study indicated that YK-624 produces more energy- and lignin-degrading enzymes for more efficient lignin biodegradation.
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Self-fusion and fusion cell isolation of transformants derived from white rot fungus Phanerochaete sordida YK-624 by simple visual method.
Journal of bioscience and bioengineering, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Tomoki Sumiya, Ojiro Kondo, Hirofumi HiraiAbstract:In order to develop a simple method for crossing two transformants, we first attempted to elucidate the fusion type (self-compatibility or -incompatible) of Phanerochaete sordida YK-624. Two transformants expressing green or red fluorescent protein derived from an auxotrophic mutant were constructed. Each recombinant protein fluoresced by expression as a fused protein with glyceraldehyde-3-phosphate dehydrogenase. On co-culture of both transformants, a number of sequential hyphal cells emitting dual fluorescence were formed at the contact areas of both hyphae. Some of the single cells isolated as protoplasts and chlamydospore from the co-cultures also expressed these fluorescent proteins. These results suggest that P. sordida YK-624 possesses a self-compatible fusion system. In addition, transformant strains with different fluorescence derived from this fungus can readily undergo self-fusion and nuclear interchange events by confrontational and mixed cultivation, and we developed a simple method that allows fused cells to be isolated as chlamydospores.
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Biotransformation and detoxification of the neonicotinoid insecticides nitenpyram and dinotefuran by Phanerochaete sordida YK-624
Environmental pollution (Barking Essex : 1987), 2019Co-Authors: Jianqiao Wang, Toshio Mori, Hirokazu Kawagishi, Tanaka Yusuke, Haruka Ohno, Jianbo Jia, Tangfu Xiao, Bing Yan, Hirofumi HiraiAbstract:Abstract Neonicotinoid insecticides have been widely used throughout the world over the last two decades. In the present study, we investigated the degradation of neonicotinoid insecticides nitenpyram (NIT) and dinotefuran (DIN) by the white-rot fungus Phanerochaete sordida YK-624. While NIT was completely degraded by P. sordida YK-624 under ligninolytic conditions, only a 20% decrease was observed under nonligninolytic conditions. On the other hand, P. sordida YK-624 degraded 31% of DIN under ligninolytic conditions after a 20-day incubation, while it did not degrade DIN under nonligninolytic conditions. We found that cytochromes P450 played a key role in the biotransformation of NIT and DIN by P. sordida YK-624. A novel NIT metabolite (E)-N-((6-chloropyridin-3-yl)methyl)-N-ethyl-N′-hydroxy acetimidamide (CPMHA) and a novel DIN metabolite N-((4aS,7aS,E)-1-methylhexahydrofuro[2,3-d]pyrimidin-2(1H)-ylidene)nitramide (PHPF) were identified in this study. In addition, to evaluate neurotoxicity, the effects of NIT, DIN and their metabolites on the viability of human neuroblastoma cells SH-SY5Y were determined. PHPF showed higher neurological toxicity than DIN, whereas the metabolite of NIT, CPMHA, showed no toxic effect. Our results indicated that the neurological toxicity of NIT could be effectively removed by P. sordida YK-624.
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Effect on growth, sugar consumption, and aerobic ethanol fermentation of homologous expression of the sugar transporter gene Pshxt1 in the white rot fungus Phanerochaete sordida YK-624.
Journal of bioscience and bioengineering, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Ojiro Kondo, Akane Masuda, Hirofumi HiraiAbstract:Major facilitator superfamily (MFS) transporters are found in all organisms. Although numerous studies have examined the functions of yeast and mold MFS transporters in terms of sugar affinity and metabolic regulation, no functional analyses of MFS sugar transporters in white rot fungi have been reported. This study identified an MFS sugar transporter gene (Pshxt1) of the white rot fungus Phanerochaete sordida YK-624 expressed in liquid culture containing low concentrations of nitrogen source. Homologous expression of Pshxt1 dramatically increased the rates of glucose, fructose, mannose, and xylose consumption. Galactose consumption increased slightly but significantly. These data suggest that Pshxt1 has broad affinity for monosaccharides. In contrast, a transformant homologously expressing Pshxt1 consumed glucose in preference to xylose in wood enzymatic-digestion liquor and liquid culture. Additionally, homologous expression of Pshxt1 improved mycelial growth, aerobic ethanol production, and simultaneous aerobic saccharification and fermentation efficiency, whereas secretion of the ligninolytic enzyme manganese peroxidase was clearly decreased in the presence of glucose by Pshxt1 expression. These results suggest that Pshxt1 is involved in the repression of ligninolytic enzyme activity via carbon catabolite repression at sufficiently high glucose concentrations for activation of primary metabolism.
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Effects of Glucose Concentration on Ethanol Fermentation of White-Rot Fungus Phanerochaete sordida YK-624 Under Aerobic Conditions
Current Microbiology, 2019Co-Authors: Toshio Mori, Hirokazu Kawagishi, Ojiro Kondo, Hirofumi HiraiAbstract:White-rot fungi are microorganisms capable of ethanol fermentation; however, the specific conditions activating ethanol fermentation are unclear in contrast to fermentation by yeasts. In this study, we investigated the conditions favoring ethanol fermentation by the white-rot fungus Phanerochaete sordida YK-624, which is able to produce ethanol from woody material. In aerobic stationary cultivation with various concentrations of glucose (0.8–33 g/l), the fungus produced ethanol in media containing an initial glucose concentration of 2.8 g/l or higher. The amount of glucose consumption, mycelial weight, and ethanol production on the second day of culture increased in a concentration-dependent manner at low glucose concentrations; however, these were saturated at high concentrations. Biomass yields (growth/glucose consumption) were decreased until the initial glucose concentration increased to 6.0 g/l, after which the biomass yields showed constant values at higher concentrations (12–33 g/l). On the other hand, ethanol yields increased with decreasing biomass yields. In short shaking cultivation using mycelial suspension, trace amounts of instantaneous aerobic ethanol production were observed with 1.1 and 2.1 g/l glucose, but the relative gene expression levels of key enzymes at the pyruvate branch point showed no significant differences between ethanol production and non-production conditions. From these experimental results, it appears that the white-rot fungus P. sordida YK-624 produces ethanol due to overflow in sugar metabolism under aerobic conditions, although P. sordida YK-624 prioritizes glucose utilization for respiratory growth.
Kazunori Nakamura - One of the best experts on this subject based on the ideXlab platform.
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Decolorization of mixtures of different reactive textile dyes by the white-rot basidiomycete Phanerochaete sordida and inhibitory effect of polyvinyl alcohol.
Chemosphere, 2005Co-Authors: Koichi Harazono, Kazunori NakamuraAbstract:We tried to decolorize mixtures of four reactive textile dyes, including azo and anthraquinone dyes, by a white-rot basidiomycete Phanerochaete sordida. P. sordida decolorized dye mixtures (200 mg l-1 each) by 90% within 48 h in nitrogen-limited glucose-ammonium media. Decolorization of dye mixtures needed Mn2+ and Tween 80 in the media. Manganese peroxidase (MnP) played a major role in dye decolorization by P. sordida. Decolorization of dye mixtures by P. sordida was partially inhibited by polyvinyl alcohol (PVA) that wastewaters from textile industries often contain. This was caused by an inhibitory effect of PVA on the decolorization of Reactive Red 120 (RR120) with MnP reaction system. Second addition of Tween 80 to the reaction mixtures in the presence of PVA improved the decolorization of RR120. These results suggest that PVA could interfere with lipid peroxidation or subsequent attack to the dye.
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Decolorization of azo dye by the white-rot basidiomycete Phanerochaete sordida and by its manganese peroxidase.
Journal of bioscience and bioengineering, 2003Co-Authors: Koichi Harazono, Yoshio Watanabe, Kazunori NakamuraAbstract:We investigated the decolorization of an azo-reactive dye, Reactive Red 120, by a white-rot basidiomycete, Phanerochaete sordida strain YK-624. In liquid culture of P. sordida in a medium containing 3% malt extract and 200 mg/l of the dye, the dye was 90.6% decolorized after 7 d. Manganese peroxidase (MnP) activity was detected during the decolorization process. The dye could be decolorized by purified MnP of P. sordida in the presence of Mn(II) and Tween 80. The involvement of lipid peroxidation during decolorization with MnP was considered. With shaking, the dye could be decolorized without the addition of hydrogen peroxide. The decolorization did not occur under anaerobic conditions, suggesting that dye decolorization by MnP is influenced by dissolved oxygen. Since catalase did not inhibit the decolorization with MnP, we inferred that the MnP catalytic cycle would be promoted by hydroperoxides formed from the decomposition of malonate or from lipid peroxidation.