• Asian-Australasian Journal of Animal Sciences
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• v.33 no.12
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• pp.1948-1956
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• 2020

Objective: The purpose of this study was to reveal the metabolic shift in the fungus cocultured with the methanogen (Methanobrevibacter thaueri). Methods: Gas chromatography-mass spectrometry was used to investigate the metabolites in anaerobic fungal (Pecoramyces sp. F1) cells and the supernatant. Results: A total of 104 and 102 metabolites were detected in the fungal cells and the supernatant, respectively. The partial least squares-discriminant analysis showed that the metabolite profiles in both the fungal cell and the supernatant were distinctly shifted when co-cultured with methanogen. Statistically, 16 and 30 metabolites were significantly (p<0.05) affected in the fungal cell and the supernatant, respectively by the co-cultured methanogen. Metabolic pathway analysis showed that co-culturing with methanogen reduced the production of lactate from pyruvate in the cytosol and increased metabolism in the hydrogenosomes of the anaerobic fungus. Citrate was accumulated in the cytosol of the fungus co-cultured with the methanogen. Conclusion: The co-culture of the anaerobic fungus and the methanogen is a good model for studying the microbial interaction between H₂-producing and H₂-utilizing microorganisms. However, metabolism in hydrogenosome needs to be further studied to gain better insight in the hydrogen transfer among microorganisms.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2003.06a
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• pp.155-156
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• 2003

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1455-1463
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• 2014

In the past, reactive oxygen species (ROS) have been considered a harmful byproduct of aerobic metabolism. However, accumulating evidence implicates redox homeostasis, which maintains appropriate ROS levels, in cell proliferation and differentiation in plants and animals. Similarly, ROS generation and signaling are instrumental in fungal development and host-fungus interaction. In fungi, NADPH oxidase, a homolog of human $gp91^{phox}$, generates superoxide and is the main source of ROS. The mechanism of activation and signaling by NADPH oxidases in fungi appears to be largely comparable to those in plants and animals. Recent studies have shown that the fungal NADPH oxidase homologs NoxA (Nox1), NoxB (Nox2), and NoxC (Nox3) have distinct functions. In particular, these studies have consistently demonstrated the impact of NoxA on the development of fungal multicellular structures. Both NoxA and NoxB (but not NoxC) are involved in host-fungus interactions, with the function of NoxA being more critical than that of NoxB.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.422-430
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• 2000

Mechanism of lignin biodegradation caused by basidiomycetes and the history of lignin biodegradation studies were briefly reviewed. The important roles of fungal extracellular ligninolytic enzymes such as lignin and manganese peroxidases (LiP and MnP) were also summarized. These enzymes were unique in their catalytic mechanisms and substrate specificities. Either LiP or MnP system is capable of oxidizing a variety of aromatic substrates via a one-electron oxidation. Extracellular fungal system for aromatic degradation is non-specific, which recently attracts many people working a bioremediation field. On the other hand, an intracellular degradation system for aromatic compounds is rather specific in the fungal cell. Structurally similar compounds were prepared and metabolized, indicating that an intracellular degradation strategy consisted of the cellular systems for substrate recognition and metabolic response. It was assumed that lignin-degrading fungi might be needed to develop multiple metabolic pathways for a variety of aromatic compounds caused by the action of non-specific ligninolytic enzymes on lignin. Our recent results on chemical stress responsible factors analyzed using mRNA differential display techniques were also mentioned.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.239.1-239
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• 1997

No Abstract, See Full Text

• Journal of Microbiology
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• v.43 no.6
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• pp.475-486
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• 2005

Fungal secondary metabolites constitute a wide variety of compounds which either playa vital role in agricultural, pharmaceutical and industrial contexts, or have devastating effects on agriculture, animal and human affairs by virtue of their toxigenicity. Owing to their beneficial and deleterious characteristics, these complex compounds and the genes responsible for their synthesis have been the subjects of extensive investigation by microbiologists and pharmacologists. A majority of the fungal secondary metabolic genes are classified as type I polyketide synthases (PKS) which are often clustered with other secondary metabolism related genes. In this review we discuss on the significance of our recent discovery of chalcone synthase (CHS) genes belonging to the type III PKS superfamily in an industrially important fungus, Aspergillus oryzae. CHS genes are known to playa vital role in the biosynthesis of flavonoids in plants. A comparative genome analyses revealed the unique character of A. oryzae with four CHS-like genes (csyA, csyB, csyC and csyD) amongst other Aspergilli (Aspergillus nidulans and Aspergillus fumigatus) which contained none of the CHS-like genes. Some other fungi such as Neurospora crassa, Fusarium graminearum, Magnaporthe grisea, Podospora anserina and Phanerochaete chrysosporium also contained putative type III PKSs, with a phylogenic distinction from bacteria and plants. The enzymatically active nature of these newly discovered homologues is expected owing to the conservation in the catalytic residues across the different species of plants and fungi, and also by the fact that a majority of these genes (csyA, csyB and csyD) were expressed in A. oryzae. While this finding brings filamentous fungi closer to plants and bacteria which until recently were the only ones considered to possess the type III PKSs, the presence of putative genes encoding other principal enzymes involved in the phenylpropanoid and flavonoid biosynthesis (viz., phenylalanine ammonia-lyase, cinnamic acid hydroxylase and p-coumarate CoA ligase) in the A. oryzae genome undoubtedly prove the extent of its metabolic diversity. Since many of these genes have not been identified earlier, knowledge on their corresponding products or activities remain undeciphered. In future, it is anticipated that these enzymes may be reasonable targets for metabolic engineering in fungi to produce agriculturally and nutritionally important metabolites.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.14-14
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• 2015

Fungi are of particular interest due to their capacity to produce an extensive array of secondary metabolites. While many secondary metabolites have no known functions to the producing fungal organisms, these metabolites have tremendous importance to humans with beneficial (e.g., antibiotics) or detrimental (e.g., mycotoxins) properties. In this study, two important filamentous fungi, Fusarium verticillioides and Mycosphaerella graminicola were selected as target species and the genes regulatory functions on the biosynthesis of secondary metabolisms were studied. Functional genomics including forward and reverse genetics, and proteomics were utilized to better understand the complex secondary metabolism regulations in both F. verticillioides and M. graminicola. Identified genes in either F. verticillioides or M. graminicola background were CPP1 (a putative protein phosphatase gene), GAC1 (encoding a GTPase activating protein), MCC1(encoding c-type cyclin), and the velvet gene, MVE1. Our data suggest that there are diverse regulatory genes on fungal secondary metabolites with distinct or overlapping functional roles.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.10
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• pp.1416-1423
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• 2013

The metabolomic profile of the anaerobic fungus Piromyces sp. F1, isolated from the rumen of goats, and how this is affected by the presence of naturally associated methanogens, was analyzed by nuclear magnetic resonance spectroscopy. The major metabolites in the fungal monoculture were formate, lactate, ethanol, acetate, succinate, sugars/amino acids and ${\alpha}$-ketoglutarate, whereas the co-cultures of anaerobic fungi and associated methanogens produced citrate. This is the first report of citrate as a major metabolite of anaerobic fungi. Univariate analysis showed that the mean values of formate, lactate, ethanol, citrate, succinate and acetate in co-cultures were significantly higher than those in the fungal monoculture, while the mean values of glucose and ${\alpha}$-ketoglutarate were significantly reduced in co-cultures. Unsupervised principal components analysis revealed separation of metabolite profiles of the fungal mono-culture and co-cultures. In conclusion, the novel finding of citrate as one of the major metabolites of anaerobic fungi associated with methanogens may suggest a new yet to be identified pathway exists in co-culture. Anaerobic fungal metabolism was shifted by associated methanogens, indicating that anaerobic fungi are important providers of substrates for methanogens in the rumen and thus play a key role in ruminal methanogenesis.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.809-816
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• 2010

Microbial biotransformations can be used to predict mammalian drug metabolism. The present investigation deals with microbial biotransformation of valdecoxib using microbial cultures. Thirty-nine bacterial, fungal, and yeast cultures were used to elucidate the biotransformation pathway of valdecoxib. A number of microorganisms metabolized valdecoxib to various levels to yield nine metabolites, which were identified by HPLC-DAD and LC-MS-MS analyses. HPLC analysis of biotransformed products indicated that a majority of the metabolites are more polar than the substrate valdecoxib. Basing on LC-MS-MS analysis, the major metabolite was identified as a hydroxymethyl metabolite of valdecoxib, whereas the remaining metabolites were produced by carboxylation, demethylation, ring hydroxylation, N-acetylation, or a combination of these reactions. The hydroxymethyl and carboxylic acid metabolites were known to be produced in metabolism by mammals. From the results, it can be concluded that microbial cultures, particularly fungi, can be used to predict mammalian drug metabolism.

• Proceedings of the Botanical Society of Korea Conference
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• 1998.07a
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• pp.10-18
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• 1998

For improvement of plants in disease resistance, it is most important to elucidate the mechanism to perceive and respond to the signal molecules of invaders. A model system with pea and its pathogen, Mycosphaerella pinodes, showed that the fungal elicitor induced defense responses in all plant species tested but that the suppressor of the fungus blocked or delayed the expression of defense responses and induced accessibility only in the host plant. In the world, many researchers believe that the pathogens` signals are recognized only on the receptors in the plasma membranes. Though we found that the ATPase and polyphosphoinositide metabolism in isolated plasma membranes responded to these fungal signals, we failed to detect specific actions of the suppressor in vitro on these plasma membrane functions. Recently, we found that ATPase (NTPases) and superoxide generating system in isolated cell wall were regulated by these fungal signals even in vitro, especially, by the suppressor in a strictly species-specific manner and also that the cell wall alone prepared an original defense system. The effects of both fungal signals on the isolated cell wall functions in vitro coincide perfectly with those on defense responses in vivo. In this treatise, we discuss the key role of the cell wall, which is plant-specific and the most exterior organelle, in determining host-parasite specificity and molecular target for improvement of plants.