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1.
Toxins (Basel) ; 16(6)2024 May 22.
Article in English | MEDLINE | ID: mdl-38922130

ABSTRACT

Fusarium verticillioides produces fumonisins, which are mycotoxins inhibiting sphingolipid biosynthesis in humans, animals, and other eukaryotes. Fumonisins are presumed virulence factors of plant pathogens, but may also play a role in interactions between competing fungi. We observed higher resistance to added fumonisin B1 (FB1) in fumonisin-producing Fusarium verticillioides than in nonproducing F. graminearum, and likewise between isolates of Aspergillus and Alternaria differing in production of sphinganine-analog toxins. It has been reported that in F. verticillioides, ceramide synthase encoded in the fumonisin biosynthetic gene cluster is responsible for self-resistance. We reinvestigated the role of FUM17 and FUM18 by generating a double mutant strain in a fum1 background. Nearly unchanged resistance to added FB1 was observed compared to the parental fum1 strain. A recently developed fumonisin-sensitive baker's yeast strain allowed for the testing of candidate ceramide synthases by heterologous expression. The overexpression of the yeast LAC1 gene, but not LAG1, increased fumonisin resistance. High-level resistance was conferred by FUM18, but not by FUM17. Likewise, strong resistance to FB1 was caused by overexpression of the presumed F. verticillioides "housekeeping" ceramide synthases CER1, CER2, and CER3, located outside the fumonisin cluster, indicating that F. verticillioides possesses a redundant set of insensitive targets as a self-resistance mechanism.


Subject(s)
Fumonisins , Fusarium , Oxidoreductases , Fumonisins/metabolism , Fusarium/genetics , Fusarium/metabolism , Fusarium/enzymology , Oxidoreductases/metabolism , Oxidoreductases/genetics , Drug Resistance, Fungal/genetics , Fungal Proteins/genetics , Fungal Proteins/metabolism , Aspergillus/genetics , Aspergillus/metabolism , Aspergillus/enzymology , Alternaria/genetics , Alternaria/enzymology
2.
Int J Biol Macromol ; 273(Pt 2): 133199, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38885866

ABSTRACT

This study aimed to produce, characterize and purify a protease from Aspergillus heteromorphus URM0269. After production by solid fermentation of wheat bran performed according to a central composite design, protease was characterized in terms of biochemical, kinetic, and thermodynamic parameters for further purification by chromatography. Proteolytic activity achieved a maximum value of 57.43 U/mL using 7.8 g of wheat bran with 40 % moisture. Protease displayed high stability in the pH and temperature ranges of 5.0-10.0 and 20-30 °C, respectively, and acted optimally at pH 7.0 and 50 °C. The enzyme, characterized as a serine protease, followed Michaelis-Menten kinetics with a maximum reaction rate of 140.0 U/mL and Michaelis constant of 11.6 mg/mL. Thermodynamic activation parameters, namely activation Gibbs free energy (69.79 kJ/mol), enthalpy (5.86 kJ/mol), and entropy (-214.39 J/mol.K) of the hydrolysis reaction, corroborated with kinetic modeling showing high affinity for azocasein. However, thermodynamic parameters suggested a reversible mechanism of unfolding. Purification by chromatography yielded a protease purification factor of 7.2, and SDS-PAGE revealed one protein band with a molecular mass of 14.7 kDa. Circular dichroism demonstrated a secondary structure made up of 45.6 % α-helices. These results show the great potential of this protease for future use in the industrial area.


Subject(s)
Aspergillus , Temperature , Thermodynamics , Aspergillus/enzymology , Kinetics , Hydrogen-Ion Concentration , Enzyme Stability , Fermentation , Peptide Hydrolases/chemistry , Peptide Hydrolases/isolation & purification , Peptide Hydrolases/metabolism , Hydrolysis , Agriculture
3.
Arch Microbiol ; 206(7): 291, 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38849576

ABSTRACT

Biomass-degrading enzymes produced by microorganisms have a great potential in the processing of agricultural wastes. In order to produce suitable biomass-degrading enzymes for releasing sugars and aroma compounds from tobacco scraps, the feasibility of directly using the scraps as a carbon source for enzyme production was investigated in this study. By comparative studies of ten fungal strains isolated from tobacco leaves, Aspergillus brunneoviolaceus Ab-10 was found to produce an efficient enzyme mixture for the saccharification of tobacco scraps. Proteomic analysis identified a set of plant biomass-degrading enzymes in the enzyme mixture, including amylases, hemicellulases, cellulases and pectinases. At a substrate concentration of 100 g/L and enzyme dosage of 4 mg/g, glucose of 17.6 g/L was produced from tobacco scraps using the crude enzyme produced by A. brunneoviolaceus Ab-10. In addition, the contents of 23 volatile molecules, including the aroma compounds 4-ketoisophorone and benzyl alcohol, were significantly increased after the enzymatic treatment. The results provide a strategy for valorization of tobacco waste by integrating the production of biomass-degrading enzymes into the tobacco scrap processing system.


Subject(s)
Aspergillus , Biomass , Nicotiana , Nicotiana/microbiology , Nicotiana/metabolism , Aspergillus/enzymology , Aspergillus/metabolism , Sugars/metabolism , Odorants/analysis , Fungal Proteins/metabolism , Glycoside Hydrolases/metabolism , Amylases/metabolism , Volatile Organic Compounds/metabolism , Plant Leaves/microbiology , Cellulases/metabolism , Polygalacturonase/metabolism
4.
BMC Microbiol ; 24(1): 209, 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38877423

ABSTRACT

Fungi can spoil the majority of baked products. Spoilage of cake during storage is commonly associated with fungi. Therefore, this study aimed to assess the quality of different types of cakes sold in the market. The most predominant fungal genera in the tested cake samples (14 samples) were Aspergillus spp., and Penicillium spp. On Potato Dextrose Agar (PDA), the medium fungal total count was 43.3 colonies /g. Aspergillus was the most dominant genus and was isolated from six samples of cake. Aspergillus was represented by 3 species namely, A. flavus, A. niger, and A. nidulans, represented by 13.32, 19.99, and 3.33 colonies /g respectively. On Malt Extract Agar (MEA) Medium, the fungal total count was 123.24 colonies / g. Aspergillus was the most dominant isolated genus from 11 samples of cake and was represented by 5 species, namely, A. flavus, A. niger, A. ochraceous, A. terreus, and A. versicolor (26. 65, 63.29, 3.33, 6.66, and 3.33 colonies / g , respectively). Twenty-four isolates (88.88 %) of the total tested twenty-seven filamentous fungi showed positive results for amylase production. Ten isolates (37.03%) of the total tested filamentous fungi showed positive results for lipase production, and finally eleven isolates (40.74 %) of the total fungal isolates showed positive results for protease production. Aflatoxins B1, B2, G1, G2, and ochratoxin A were not detected in fourteen collected samples of cake. In this study, clove oil was the best choice overpeppermint oil and olive oil for preventing mold development when natural agents were compared. It might be due to the presence of a varietyof bioactive chemical compounds in clove oil, whose major bioactive component is eugenol, which acts as an antifungal reagent. Therefore, freshly baked cake should be consumed within afew days to avoid individuals experiencing foodborne illnesses.


Subject(s)
Food Microbiology , Fungi , Mycotoxins , Fungi/isolation & purification , Fungi/classification , Fungi/enzymology , Fungi/genetics , Mycotoxins/analysis , Aspergillus/isolation & purification , Aspergillus/enzymology , Penicillium/isolation & purification , Penicillium/enzymology , Food Contamination/analysis , Aflatoxins/analysis , Lipase/metabolism , Amylases/metabolism , Amylases/analysis
5.
Int J Mol Sci ; 25(9)2024 Apr 27.
Article in English | MEDLINE | ID: mdl-38732010

ABSTRACT

L-asparaginase is an essential drug used to treat acute lymphoid leukemia (ALL), a cancer of high prevalence in children. Several adverse reactions associated with L-asparaginase have been observed, mainly caused by immunogenicity and allergenicity. Some strategies have been adopted, such as searching for new microorganisms that produce the enzyme and applying protein engineering. Therefore, this work aimed to elucidate the molecular structure and predict the immunogenic profile of L-asparaginase from Penicillium cerradense, recently revealed as a new fungus of the genus Penicillium and producer of the enzyme, as a motivation to search for alternatives to bacterial L-asparaginase. In the evolutionary relationship, L-asparaginase from P. cerradense closely matches Aspergillus species. Using in silico tools, we characterized the enzyme as a protein fragment of 378 amino acids (39 kDa), including a signal peptide containing 17 amino acids, and the isoelectric point at 5.13. The oligomeric state was predicted to be a homotetramer. Also, this L-asparaginase presented a similar immunogenicity response (T- and B-cell epitopes) compared to Escherichia coli and Dickeya chrysanthemi enzymes. These results suggest a potentially useful L-asparaginase, with insights that can drive strategies to improve enzyme production.


Subject(s)
Asparaginase , Computer Simulation , Penicillium , Asparaginase/chemistry , Asparaginase/immunology , Asparaginase/metabolism , Penicillium/immunology , Penicillium/enzymology , Amino Acid Sequence , Fungal Proteins/chemistry , Fungal Proteins/immunology , Fungal Proteins/metabolism , Epitopes, B-Lymphocyte/immunology , Epitopes, B-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/immunology , Epitopes, T-Lymphocyte/chemistry , Humans , Aspergillus/immunology , Aspergillus/enzymology , Escherichia coli/genetics , Dickeya chrysanthemi/enzymology , Dickeya chrysanthemi/immunology , Models, Molecular
6.
Phytochemistry ; 224: 114149, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38763314

ABSTRACT

Farnesylated chalcones were favored by researchers due to their different biological activities. However, only five naturally occurring farnesylated chalcones were described in the literature until now. Here, the farnesylation of six chalcones by the Aspergillus terreus aromatic prenyltransferase AtaPT was reported. Fourteen monofarnesylated chalcones (1F1-1F5, 2F1-2F3, 3F1, 3F2, 4F1, 4F2, 5F1, 6F1, and 6F2) and a difarnesylated product (2F3) were obtained, enriching the diversity of natural farnesylated chalcones significantly. Ten of them are C-farnesylated products, which complement O-farnesylated chalcones by chemical synthesis. Fourteen products have not been reported prior to this study. Nine of the produced compounds (1F2-1F5, 2F1-2F3, 5F1, and 6F1) exhibited inhibitory effect on α-glucosidase with IC50 values ranging from 24.08 ± 1.44 to 190.0 ± 0.28 µM. Among them, compounds 2F3 with IC50 value at 24.08 ± 1.44 µM and 1F4 with IC50 value at 30.09 ± 0.59 µM showed about 20 times stronger than the positive control acarbose with an IC50 at 536.87 ± 24.25 µM in α-glucosidase inhibitory assays.


Subject(s)
Aspergillus , Chalcones , Dimethylallyltranstransferase , Dimethylallyltranstransferase/metabolism , Dimethylallyltranstransferase/chemistry , Dimethylallyltranstransferase/antagonists & inhibitors , Chalcones/chemistry , Chalcones/pharmacology , Chalcones/metabolism , Aspergillus/enzymology , Aspergillus/chemistry , Molecular Structure , Prenylation , Structure-Activity Relationship , Glycoside Hydrolase Inhibitors/chemistry , Glycoside Hydrolase Inhibitors/pharmacology , alpha-Glucosidases/metabolism , alpha-Glucosidases/chemistry , Dose-Response Relationship, Drug
7.
N Biotechnol ; 82: 25-32, 2024 Sep 25.
Article in English | MEDLINE | ID: mdl-38697469

ABSTRACT

Aspergillus vadensis CBS 113365, a close relative of A. niger, has been suggested as a more favourable alternative for recombinant protein production as it does not acidify the culture medium and produces very low levels of extracellular proteases. The aim of this study was to investigate the underlying cause of the non-amylolytic and non-proteolytic phenotype of A. vadensis CBS 113365. Our results demonstrate that the non-functionality of the amylolytic transcription factor AmyR in A. vadensis CBS 113365 is primarily attributed to the lack of functionality of its gene's promoter sequence. In contrast, a different mechanism is likely causing the lack of PrtT activity, which is the main transcriptional regulator of protease production. The findings presented here not only expand our understanding of the genetic basis behind the distinct characteristics of A. vadensis CBS 113365, but also underscore its potential as a favourable alternative for recombinant protein production.


Subject(s)
Aspergillus , Fungal Proteins , Aspergillus/genetics , Aspergillus/metabolism , Aspergillus/enzymology , Fungal Proteins/genetics , Fungal Proteins/metabolism , Promoter Regions, Genetic , Recombinant Proteins/metabolism , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics , Proteolysis , Peptide Hydrolases/metabolism , Peptide Hydrolases/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Trans-Activators
8.
J Microbiol Biotechnol ; 34(5): 1017-1028, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38803105

ABSTRACT

Lignocellulolytic enzymes play a crucial role in efficiently converting lignocellulose into valuable platform molecules in various industries. However, they are limited by their production yields, costs, and stability. Consequently, their production by producers adapted to local environments and the choice of low-cost raw materials can address these limitations. Due to the large amounts of olive stones (OS) generated in Morocco which are still undervalued, Penicillium crustosum, Fusarium nygamai, Trichoderma capillare, and Aspergillus calidoustus, are cultivated under different fermentation techniques using this by-product as a local lignocellulosic substrate. Based on a multilevel factorial design, their potential to produce lignocellulolytic enzymes during 15 days of dark incubation was evaluated. The results revealed that P. crustosum expressed a maximum total cellulase activity of 10.9 IU/ml under sequential fermentation (SF) and 3.6 IU/ml of ß-glucosidase activity under submerged fermentation (SmF). F. nygamai recorded the best laccase activity of 9 IU/ml under solid-state fermentation (SSF). Unlike T. capillare, SF was the inducive culture for the former activity with 7.6 IU/ml. A. calidoustus produced, respectively, 1,009 µg/ml of proteins and 11.5 IU/ml of endoglucanase activity as the best results achieved. Optimum cellulase production took place after the 5th day under SF, while ligninases occurred between the 9th and the 11th days under SSF. This study reports for the first time the lignocellulolytic activities of F. nygamai and A. calidoustus. Furthermore, it underlines the potential of the four fungi as biomass decomposers for environmentally-friendly applications, emphasizing the efficiency of OS as an inducing substrate for enzyme production.


Subject(s)
Fermentation , Lignin , Olea , Lignin/metabolism , Olea/microbiology , Aspergillus/enzymology , Aspergillus/metabolism , Cellulase/metabolism , Cellulase/biosynthesis , Laccase/metabolism , Laccase/biosynthesis , Penicillium/enzymology , Penicillium/metabolism , beta-Glucosidase/metabolism , beta-Glucosidase/biosynthesis , Fusarium/enzymology , Fusarium/metabolism , Trichoderma/enzymology , Trichoderma/metabolism , Fungi/enzymology , Fungi/metabolism , Morocco , Fungal Proteins/metabolism
9.
Environ Sci Pollut Res Int ; 31(27): 39217-39231, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38814560

ABSTRACT

To overcome the human and animal survivability risk, sustainable development is the only option on earth that can be achieved through the maximum use of renewable environmental resources. Recycling of waste paper is an emerging waste management approach to conserve natural resources. Herein, we studied enzyme-mediated process to recycle the xerographic paper by using the crude fungal extract from indigenously isolated fungi identified as Aspergillus assiutensis. The fungal enzyme cocktail has been characterized for the production of multiple enzymes namely cellulase, amylase, xylanase, pectinase, and protease. All these enzymes have pH optima in the acidic range and except cellulase and all the enzymes are stable from 10 to 80 C. In the zymogram analysis, pectinase, xylanase, amylase, and cellulase were detected at 68 kDa, ~ 54 kDa, 38 kDa, and 30 kDa, respectively. Also, the presence of protease was confirmed by the clear zone at 68, 31, and 16 kDa. A 26% decrease in the kappa number and reduction in Hex A of the pulp was observed on the treatment of the pulp with enzyme as compared to the control pulp without any treatment. The physical and chemical properties of the pulp were also improved by enzyme-mediated pulping as compared to the control The physiochemical parameter of the effluent like TDS was reduced (397 ppm) significantly in comparison to chemical deinking process and it was within the permissible limit. BOD and alkalinity were reduced when the enzymes and chemical dosage were used in combination. These results indicate that chemi-enzymatic deinking is most promising to reduce or remove the pollution parameters including ink and this approach can be used in the paper and pulp industry for sustainable development.


Subject(s)
Aspergillus , Paper , Recycling , Aspergillus/enzymology , Polygalacturonase , Cellulase
10.
Mycologia ; 116(4): 477-486, 2024.
Article in English | MEDLINE | ID: mdl-38819952

ABSTRACT

The need for industrially and biotechnologically significant enzymes, such as phytase, is expanding daily as a result of the increased use of these enzymes in a variety of operations, including the manufacture of food, animal feed, and poultry feed. This study sought to characterize purified phytase from A. awamori AFE1 isolated from longhorn beetle for its prospect in industrial applications. Ammonium sulfate precipitation, ion-exchange chromatography, and gel-filtration chromatography were used to purify the crude enzyme obtained from submerged fermentation using phytase-producing media, and its physicochemical characteristics were examined. The homogenous 46.8-kDa phytase showed an 8.1-fold purification and 40.7% recovery. At 70 C and pH 7, the optimum phytase activity was noted. At acidic pH 4-6 and alkaline pH 8-10, it likewise demonstrated relative activity of 88-95% and 67-88%, respectively. It showed 67-70% residual activity between 30 and 70 C after 40 min, and 68-94% residual activity between pH 2 and 12 after 2 h. The presence of Hg+, Mg2+, and Al3+ significantly decreased the enzymatic activity, whereas Ca2+ and Cu2+ enhanced it. Ascorbic acid increased the activity of the purified enzyme, whereas ethylenediaminetetraacetic acid (EDTA) and mercaptoethanol inhibited it. The calculated values for Km and Vmax were 55.4 mM and1.99 µmol/min/mL respectively. A. awamori phytase, which was isolated from a new source, showed unique and remarkable qualities that may find use in industrial operations such as feed pelleting and food processing.


Subject(s)
6-Phytase , Aspergillus , Coleoptera , Gastrointestinal Tract , Animals , 6-Phytase/metabolism , 6-Phytase/isolation & purification , 6-Phytase/chemistry , Coleoptera/microbiology , Hydrogen-Ion Concentration , Aspergillus/enzymology , Aspergillus/metabolism , Temperature , Enzyme Stability , Molecular Weight , Fermentation , Metals/pharmacology , Metals/metabolism
11.
Biosci Biotechnol Biochem ; 88(7): 816-823, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38621718

ABSTRACT

In this study, we investigated a deleterious mutation in the ß-xylosidase gene, xylA (AkxylA), in Aspergillus luchuensis mut. kawachii IFO 4308 by constructing an AkxylA disruptant and complementation strains of AkxylA and xylA derived from A. luchuensis RIB2604 (AlxylA), which does not harbor the mutation in xylA. Only the AlxylA complementation strain exhibited significantly higher growth and substantial ß-xylosidase activity in medium containing xylan, accompanied by an increase in XylA expression. This resulted in lower xylobiose and higher xylose concentrations in the mash of barley shochu. These findings suggest that the mutation in xylA affects xylose levels during the fermentation process. Because the mutation in xylA was identified not only in the genome of strain IFO 4308 but also the genomes of other industrial strains of A. luchuensis and A. luchuensis mut. kawachii, these findings enhance our understanding of the genetic factors that affect the fermentation characteristics.


Subject(s)
Aspergillus , Fermentation , Mutation , Xylose , Xylosidases , Xylosidases/genetics , Xylosidases/metabolism , Aspergillus/genetics , Aspergillus/enzymology , Xylose/metabolism , Xylans/metabolism , Disaccharides/metabolism , Hordeum/microbiology , Hordeum/genetics
12.
J Biosci Bioeng ; 138(1): 73-82, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38643032

ABSTRACT

Mucilage is a gelatinous and sticky hydrophilic polysaccharide released from epidermal cells of seed coat after the hydration of mature seeds and is composed primarily of unbranched rhamnogalacturonan I (RG-I). In this study, we produced a recombinant endo-RG-I hydrolase from Aspergillus aculeatus (AaRhgA) in the fission yeast Schizosaccharomyces pombe and examined its substrate preference for pyridylaminated (PA) RG-I with the various degrees of polymerization (DP). Recombinant AaRhgA requires PA-RG-I with a DP of 10 or higher for its hydrolase activity. We heterologously expressed the AarhgA gene under the strong constitutive promoter, cauliflower mosaic virus 35S promoter, in Arabidopsis thaliana. In a series of biochemical analyses of each mucilage fraction released from the water-imbibed seeds of the transgenic plants, we found the enhanced deposition of the transparent mucilage layer that existed in the peripheral regions of the adherent mucilage and was not stained with ruthenium red. This study demonstrated the feasibility of manipulating the mucilage organization by heterologous expression of the endo-RG-I hydrolase.


Subject(s)
Arabidopsis , Aspergillus , Pectins , Plants, Genetically Modified , Seeds , Arabidopsis/genetics , Arabidopsis/metabolism , Aspergillus/enzymology , Aspergillus/genetics , Aspergillus/metabolism , Pectins/metabolism , Plants, Genetically Modified/metabolism , Plants, Genetically Modified/genetics , Seeds/metabolism , Plant Mucilage/metabolism , Plant Mucilage/chemistry , Schizosaccharomyces/genetics , Schizosaccharomyces/metabolism , Schizosaccharomyces/enzymology , Recombinant Proteins/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/chemistry , Promoter Regions, Genetic , Caulimovirus/genetics , Caulimovirus/metabolism , Glycoside Hydrolases/metabolism , Glycoside Hydrolases/genetics , Glycoside Hydrolases/chemistry , Substrate Specificity
13.
Int J Biol Macromol ; 266(Pt 2): 131309, 2024 May.
Article in English | MEDLINE | ID: mdl-38580019

ABSTRACT

Enzymatic degradation of plant biomass requires the coordinated action of various enzymes. In this study, the production of reducing sugars from pectic substrates and sugar beet pulp (SBP) was investigated and compared using commercial enzyme preparations, including M2, pectinase (E1), Viscozyme L (V-L) and L-40. V-L, a cellulolytic enzyme mix produced by Aspergillus sp. was further evaluated as the most robust enzyme cocktail with the strongest SBP degradation ability in terms of the release of monosaccharides, methanol, and acetate from SBP. Mass-spectrometry-based proteomics analysis of V-L revealed 156 individual proteins. Of these, 101 proteins were annotated as containing a carbohydrate-active enzyme module. Notably, of the 50 most abundant proteins, ca. 44 % were predicted to be involved in pectin degradation. To reveal the role of individual putative key enzymes in pectic substrate decomposition, two abundant galacturonases (PglA and PglB), were heterologously expressed in Pichia pastoris and further characterized. PglA and PglB demonstrated maximum activity at 57 °C and 68 °C, respectively, and exhibited endo-type cleavage patterns towards polygalacturonic acid. Further studies along this line may lead to a better understanding of efficient SBP degradation and may help to design improved artificial enzyme mixtures with lower complexity for future application in biotechnology.


Subject(s)
Pectins , Proteomics , Pectins/metabolism , Proteomics/methods , Substrate Specificity , Polygalacturonase/metabolism , Polygalacturonase/chemistry , Beta vulgaris/chemistry , Beta vulgaris/metabolism , Aspergillus/enzymology
14.
J Nat Prod ; 87(4): 1171-1178, 2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38557026

ABSTRACT

The potential of natural products as pharmaceutical and agricultural agents is based on their large structural diversity, resulting in part from modifications of the backbone structure by tailoring enzymes during biosynthesis. Flavin-dependent monooxygenases (FMOs), as one such group of enzymes, play an important role in the biosynthesis of diverse natural products, including cyclodipeptide (CDP) derivatives. The FMO PboD was shown to catalyze C-3 hydroxylation at the indole ring of cyclo-l-Trp-l-Leu in the biosynthesis of protubonines, accompanied by pyrrolidine ring formation. PboD substrate promiscuity was investigated in this study by testing its catalytic activity toward additional tryptophan-containing CDPs in vitro and biotransformation in Aspergillus nidulans transformants bearing a truncated protubonine gene cluster with pboD and two acetyltransferase genes. High acceptance of five CDPs was detected for PboD, especially of those with a second aromatic moiety. Isolation and structure elucidation of five pyrrolidine diketopiperazine products, with two new structures, proved the expected stereospecific hydroxylation and pyrrolidine ring formation. Determination of kinetic parameters revealed higher catalytic efficiency of PboD toward three CDPs consisting of aromatic amino acids than of its natural substrate cyclo-l-Trp-l-Leu. In the biotransformation experiments with the A. nidulans transformant, modest formation of hydroxylated and acetylated products was also detected.


Subject(s)
Aspergillus , Diketopiperazines , Aspergillus/enzymology , Aspergillus/chemistry , Aspergillus nidulans/enzymology , Aspergillus nidulans/metabolism , Diketopiperazines/chemistry , Diketopiperazines/metabolism , Flavins/metabolism , Hydroxylation , Mixed Function Oxygenases/metabolism , Mixed Function Oxygenases/chemistry , Molecular Structure , Peptides, Cyclic/chemistry , Peptides, Cyclic/metabolism , Substrate Specificity
15.
J Asian Nat Prod Res ; 26(6): 681-689, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38329449

ABSTRACT

Sea cucumber-derived fungi have attracted much attention due to their capacity to produce an incredible variety of secondary metabolites. Genome-wide information on Aspergillus micronesiensis H39 obtained using third-generation sequencing technology (PacBio-SMRT) showed that the strain contains nonribosomal peptide synthetase (NRPS)-like gene clusters, which aroused our interest in mining its secondary metabolites. 11 known compounds (1-11), including two γ-aromatic butenolides (γ-AB) and five cytochalasans, were isolated from A. micronesiensis H39. The structures of the compounds were determined by NMR and ESIMS, and comparison with those reported in the literature. From the perspective of biogenetic origins, the γ-butyrolactone core of compounds 1 and 2 was assembled by NRPS-like enzyme. All of the obtained compounds showed no inhibitory activity against drug-resistant bacteria and fungi, as well as compounds 1 and 2 had no anti-angiogenic activity against zebrafish.


Subject(s)
4-Butyrolactone , 4-Butyrolactone/analogs & derivatives , Aspergillus , Multigene Family , Peptide Synthases , Peptide Synthases/genetics , Molecular Structure , 4-Butyrolactone/pharmacology , 4-Butyrolactone/chemistry , Aspergillus/enzymology , Aspergillus/chemistry , Aspergillus/genetics , Animals , Zebrafish
16.
Appl Microbiol Biotechnol ; 107(2-3): 735-747, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36607403

ABSTRACT

Cytochrome P450 monooxygenases (CYP450s) are abundant in eukaryotes, specifically in plants and fungi where they play important roles in the synthesis and degradation of secondary metabolites. In eukaryotes, the best studied "self-sufficient" CYP450s, with a fused redox partner, belong to the CYP505 family. Members of the CYP505 family are generally considered sub-terminal fatty acid hydroxylases. CYP505E3 from Aspergillus terreus, however, gives remarkable in-chain hydroxylation at the ω-7 position of C10 to C16 alkanes and C12 and C14 fatty alcohols. Because CYP505E3 is a promising catalyst for the synthesis of δ-dodecalactone, we set out to delineate the unique ω-7 hydroxylase activity of CYP505E3. CYP505E3 and six additional CYP505Es as well as four closely related CYP505s from four different subfamilies were expressed in Pichia pastoris. Only the CYP505Es, sharing more than 70% amino acid identity, displayed significant ω-7 hydroxylase activity toward 1-dodecanol, dodecanoic acid, and tetradecanoic acid giving products that can readily be converted to δ-dodecalactone. Concentrations of δ-dodecalactone, directly extracted from dodecanoic acid biotransformations, were higher than previously obtained with E. coli. Searches of the UniProt and NCBI databases yielded a total of only 23 unique CYP505Es, all from the Aspergillaceae. Given that CYP505Es with this remarkable activity occur in only a few Aspergillus and Penicillium spp., we further explored the genetic environments in which they occur. These were found to be very distinct environments which include a specific ABC transporter but could not be linked to apparent secondary metabolite gene clusters. KEY POINTS: • Identified CYP505Es share > 70% amino acid identity. • CYP505Es hydroxylate 1-dodecanol, dodecanoic, and tetradecanoic acid at ω-7 position. • CYP505E genes occur in Aspergillus and Penicillium spp. near an ABC transporter.


Subject(s)
Aspergillus , Cytochrome P-450 Enzyme System , Amino Acids/metabolism , Cytochrome P-450 Enzyme System/genetics , Cytochrome P-450 Enzyme System/metabolism , Dodecanol/metabolism , Hydroxylation , Myristic Acid , Aspergillus/enzymology , Aspergillus/genetics
17.
Org Lett ; 24(38): 7037-7041, 2022 09 30.
Article in English | MEDLINE | ID: mdl-36126322

ABSTRACT

We report the identification of the tnd biosynthetic cluster from the marine-derived fungus Aspergillus flavipes and the in vivo characterization of a cryptic type I diterpene synthase. The heterologous expression of the bifunctional terpene synthase led to the discovery of a diterpene backbone, talarodiene, harboring a benzo[a]cyclopenta[d]cyclooctane tricyclic fused ring system. The conversion of geranylgeranyl diphosphate to talarodiene was investigated using 13C-labeling studies, and stable isotope tracer experiments showed the biotransformation of talarodiene into talaronoid C.


Subject(s)
Alkyl and Aryl Transferases , Aspergillus , Diterpenes , Alkyl and Aryl Transferases/metabolism , Aquatic Organisms/enzymology , Aspergillus/enzymology , Cyclooctanes , Diterpenes/metabolism , Polyisoprenyl Phosphates/chemistry
18.
Free Radic Biol Med ; 185: 76-89, 2022 05 20.
Article in English | MEDLINE | ID: mdl-35489562

ABSTRACT

The airway epithelium maintains tight barrier integrity to prevent penetration of pathogens; thus, impairment of the barrier function is an important and common histological feature in asthmatic patients. Proteolytic allergens from fungi, pollen, and house dust mites can disrupt epithelial barrier integrity, but the mechanism remains unclear. Aspergillus oryzae protease (AP)-induced mitochondrial reactive oxygen species (ROS) contribute to the epithelial inflammatory response. However, as mitochondrial ROS affect various cellular functions, such as metabolism, cell death, cell proliferation, and redox homeostasis through signal transduction, it is difficult to understand the detailed action mechanism of AP by measuring changes in a single gene or protein of a specific signaling pathway. Moreover, mitochondrial ROS can directly oxidize DNA to activate transcription, thereby affecting the expression of various genes at the transcriptional level. Therefore, we conducted whole-genome analysis and used a network-based approach to understand the effect of AP and AP-induced mitochondrial ROS in human primary airway epithelial cells and to evaluate the mechanistic basis for AP-mediated epithelial barrier dysfunction. Our results indicate that production of mitochondrial ROS following AP exposure induce mitochondrial dysfunction at an early stage. Over time, changes in genome expression were further expanded without remaining mitochondrial ROS. Specifically, genes involved in the apoptotic functions and intercellular junctions were affected, consequently impairing the cellular barrier integrity. This change was recovered by scavenging mitochondrial ROS at an early point after exposure to AP. In conclusion, our findings indicate that instantly increased mitochondrial ROS at the time of exposure to allergenic proteases consequently induces epithelial barrier dysfunction at a later time point, resulting in pathological changes. These data suggest that antioxidant therapy administered immediately after exposure to proteolytic antigens may be effective in maintaining epithelial barrier function.


Subject(s)
Aspergillus , Gene Regulatory Networks , Mitochondria , Oxidants , Peptide Hydrolases , Allergens , Aspergillus/enzymology , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Humans , Mitochondria/metabolism , Oxidants/metabolism , Peptide Hydrolases/genetics , Peptide Hydrolases/metabolism , Reactive Oxygen Species/metabolism
20.
J Biomol Struct Dyn ; 40(10): 4328-4340, 2022 07.
Article in English | MEDLINE | ID: mdl-33308034

ABSTRACT

The spread of fungal growth causes enormous economic, agricultural, and health problems for humans, such as Aspergillus sp., which produce aflatoxins. Thus, the inhibition of aflatoxin production became a precious target. In this research, the thioesterase (TE) domain from Polyketide synthase enzyme was selected to employ the in silico docking, using AutoDock Vina, against 623 natural compounds from the South African natural compound database (SANCDB), to identify potential inhibitors that can selectively inhibit thioesterase domain. The top ten inhibitors components were pinocembrin, typhaphthalide, p-coumaroylputrescine, dilemmaone A, 9-angelylplatynecine, 2,4,6-octatrienal, 4,8-dichloro-3,7-dimethyl-, (2e,4z,6e)-, lilacinobiose, 1,3,7-octatriene, 5,6-dichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(e)]-(-)- (9ci), lilacinobiose, 1,3,7-octatriene, 5,6-dichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(e)]-(-)- (9ci), 1,3,7-octatriene, 1,5,6-trichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(z,e)] and 9-angelylhastanecine and that depending on the lowest binding energy, the best chemical interactions and the best drug-likeness. The results of those components gave successful inhibition with the thioesterase domain. So, they can be used for inhibition and controlling aflatoxin contamination of agriculture crop yields, specially, pinocembrin which gave promising results.Communicated by Ramaswamy H. Sarma.


Subject(s)
Aflatoxins , Aspergillus , Polyketide Synthases , Aflatoxins/chemistry , Aspergillus/enzymology , Polyketide Synthases/chemistry
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