Anticancer properties of dried-pericarp water extracts of Camellia japonica L. fermented with Aspergillus oryzae through regulation of IGFBP-2/mTOR pathway

This study aimed to investigate the anticancer activity of dried-pericarp water extract of fermented C. japonicus (CJ). The dried-pericarp water extracts of CJ were fermented using Aspergillus oryzae and Saccharomyces cerevisiae at 30 °C and 35 °C. The anticancer activities of both water extracts fermented at 30 °C and 35 °C using A. oryzae against FaDu cells were remarkably changed compared with unfermented dried-pericarp water extract of CJ, which has no anticancer activity. Cleaved-PARP, caspase 3, and apoptotic cells stained with annexin V/PI were significantly increased by treatment with A. oryzae extracts fermented at 30 °C. The insulin-like growth factor-binding protein 2 (IGFBP-2) protein level and mTOR phosphorylation by A. oryzae fermented extracts (AOFE) were dramatically reduced, and the expression levels of IGFBP-2 and phosphorylated mTOR were significantly increased depending on the glucose concentrations in FaDu cells. These results suggested that the cell viabilities in AOFE were restored as the glucose concentrations increased. Furthermore, it was confirmed LC/MS/MS that the content of gallic acid was increased by fermentation of Aspergillus oryzae (5.596 ± 0.1746 μg/mg) compared to the unfermented extract (1.620 ± 0.0432 μg/mg). Based on these results, the anticancer effect of AOFE was achieved through inhibition of the IGFBP-2/mTOR signaling pathway. These results suggest that AOFE may be a potential treatment for head and neck cancer.

Enhancing Activities of Salt-Tolerant Proteases Secreted by Aspergillus oryzae Using Atmospheric and Room-Temperature Plasma Mutagenesis

Aspergillus oryzae 3.042 was mutagenized using atmospheric and room-temperature plasma (ARTP) technology to enhance its salt-tolerant proteases activity. Compared to the starting strain, mutant H8 subjected to 180 s of ARTP treatment exhibited excellent genetic stability (15 generations), growth rate, and significantly increased activities of neutral proteases, alkaline proteases, and aspartyl aminopeptidase during fermentation. Mutant H8 significantly enhanced the contents of 1-5 kDa peptides, aspartic acid, serine, threonine, and cysteine in soy sauce by 16.61, 7.69, 17.30, 8.61, and 45.00%, respectively, but it had no effects on the contents of the other 14 free amino acids (FAAs) due to its slightly enhanced acidic proteases activity. Analyses of transcriptional expressions of salt-tolerant alkaline protease gene (AP, gi: 217809) and aspartyl aminopeptidase gene (AAP, gi: 6165646) indicated that their expression levels were increased by approximately 30 and 27%, respectively. But no mutation was found in the sequences of AP and AAP expression cassettes, suggesting that the increased activities of proteases in mutant H8 should be partially attributed to the increased expression of proteases. ARTP technology showed great potential in enhancing the activities of salt-tolerant proteases from A. oryzae.

Polyphasic Assessment of Aflatoxin Production Potential in Selected Aspergilli

This study investigated the aflatoxin production potentials of selected fungi using a polyphasic approach. Internally transcribed spacer region of the fungi was amplified using the polymerase chain reaction. Forty-five Aspergillus strains were further assessed for aflatoxin production using the conventional methods such as growth on yeast extract sucrose, β-cyclodextrin neutral red desiccated coconut agar (β-CNRDCA); expression of the aflatoxin regulatory genes and the use of both thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). A large proportion (82.22%) of the isolates harbored the Nor-1 gene while 55.56%, 68.89%, and 80% possessed the ver-1, omt-A, and aflR genes, respectively. All 100% the isolates harbored the aflJ gene. Twenty-three isolates were positive for aflatoxin production based on the yeast extract sucrose medium (YES) test; ammonium vapor test (51%), yellow pigment production (75.5%), and β-CNRDCA tests; and blue/green fluorescence (57.7%). Based on TLC detection 42.2% produced aflatoxins while in the HPLC, total aflatoxin (AFTOT) production concentrations ranged from 6.77-71,453 µg/g. Detectable aflatoxin B1 (AFB1) concentrations obtained from the HPLC ranged between 3.76 and 70,288 µg/g; 6.77 and 242.50 µg/g for aflatoxin B2 (AFB2); 1.87 and 745.30 µg/g for aflatoxin G1 (AFG1); and 1.67 and 768.52 µg/g for aflatoxin G2 (AFG2). AFTOT contamination levels were higher than European Union tolerable limits (4 µg/kg). The regression coefficient was one (R2 = 1) while significant differences exist in the aflatoxin concentrations of Aspergillus (p ≤ 0.05). This study reports the potentials of Aspergillus oryzae previously known as a non-aflatoxin producer to produce AFG1, AFG2, AFB1, and AFB2 toxins. Aspergillus species in feedlots of animals reared for food are capable of producing aflatoxins which could pose hazards to health.

Separation, biochemical characterization and salt-tolerant mechanisms of alkaline protease from Aspergillus oryzae

BACKGROUND

The salt tolerance of proteases secreted by Aspergillus oryzae 3.042 closely relates to the utilization of raw materials and the quality of soy sauce. However, little is known about the salt-tolerant proteases and their salt-tolerant mechanisms.

RESULTS

In this study, we isolated and identified a salt-tolerant alkaline protease (AP, approximately 29 kDa) produced by A. oryzae 3.042. It was considered as a metal-ion-independent serine protease. The optimum and stable pH values were both pH 9.0 and the optimum temperature was 40 °C. Over 20% relative activity of AP remained in the presence of 3.0 mol L^-1 NaCl after 7 days, but its K_m and V_max were only mildly influenced by the presence of 3.0 mol L^-1 NaCl, indicating its outstanding salt tolerance. Furthermore, AP was more stable than non-salt-tolerant protease at high salinity. The salt-tolerant mechanisms of AP could be due to more salt bridges, higher proportion of ordered secondary structures and stronger hydrophobic amino acid residues in the interior.

CONCLUSIONS

The above results are vital for maintaining, activating and/or modulating the activity of AP in high-salt environments. They would also provide theoretical guidance for the modification of AP and the engineering of A. oryzae 3.042 so as to secrete more AP. © 2018 Society of Chemical Industry.

Effect of temperature on saccharification and oligosaccharide production efficiency in koji amazake

Koji amazake, prepared from rice koji, is a traditional Japanese sweet beverage. The main source of sweetness is glucose derived from rice starch following digestion by enzymes of Aspergillus oryzae during saccharification. The temperature of this process was empirically determined as 45°C-60°C, but no studies have systematically investigated the effect of temperature on saccharification efficiency. We addressed this in the present study by evaluating saccharification efficiency at various temperatures. We found that glucose content was the highest at 50°C (100%) and was reduced at temperatures of 40°C (66.4%), 60°C (91.9%), and 70°C (76.6%). We previously reported that 12 types of oligosaccharides are present in koji amazake; the levels of eight of these, namely nigerose, kojibiose, trehalose, isomaltose, gentiobiose, raffinose, panose, and isomaltotriose, were the highest at 50°C-60°C, whereas sophorose production was maximal at 70°C. Based on these findings, we initially performed saccharification at 50°C and then switched the temperature to 70°C. The maximum amount of each saccharide including sophorose that was produced was close to the values obtained at these two temperatures. Thus, oligosaccharide composition of koji amazake is dependent on saccharification temperature. These findings provide useful information for improving the consumer appeal of koji amazake by enhancing oligosaccharide content.

Development of Quantitative Analysis Techniques for Saccharification Reactions Using Raman Spectroscopy

A technique for the analysis of saccharification reactions by a specific enzyme was developed on the basis of Raman spectroscopy using multivariate analysis. It is a microvolume, quantitative, and in situ technique, which can be used for studying saccharification processes in plant tissues. Prediction models for quantitative analysis of maltose, glucose, and starch were built with partial least squares regression (PLSR) analysis to monitor the saccharification process caused by α-amylase. We examined the reliability of the prediction models built using seven test samples. The spectral regions used to build the models were optimized for each sugar and were selected in such a manner that they did not overlap with strong protein and lipid bands that generally exist in plant tissues. The models were validated by monitoring the composition of reduced sugars and starch in a reactor and by comparing the results with those obtained by a conventional method. The results of Raman analysis and the conventional method showed good agreement for the reaction with α-amylase; however, it is not perfect for reactions with a different enzyme, especially β-amylase. The results suggest that the present Raman technique is reliable and useful for sugar analysis. However, the prediction model built for a specific enzyme is valid only for that enzyme.

Impact of Iron-Enriched Aspergillus oryzae on Iron Bioavailability, Safety, and Gut Microbiota in Rats

Iron deficiency is a leading global nutritional problem. Ferrous sulfate (FeSO₄) is the most common iron source used for supplementation. Because of many side effects associated with its consumption, it is important to identify new forms of iron. The objectives of this study were to assess the bioavailability of iron-enriched Aspergillus oryzae, Aspiron (ASP), evaluate the toxicity of high-dose iron supplementation with ASP, and determine the ASP impact on gut microbiota in rats. In this study, we investigated iron bioavailability using the hemoglobin repletion test. Aspartate aminotransferase, alanine aminotransferase, and blood urea nitrogen levels were determined to evaluate the effect on liver and kidney functions. Protein carbonyls were measured to assess oxidative damage to proteins. Fecal samples at the end of the 14 day repletion period were used for 16S rRNA sequencing for gut microbiota analysis. The slope ratio method using a common intercept linear regression model was used to compare the bioavailability of ASP to FeSO₄. Iron repletion increased hemoglobin concentrations with both ASP and FeSO₄ treatments compared to the control group, except in the lowest ASP group. The slope ratio indicated that relative iron bioavailability of ASP was 60% of that of FeSO₄ when hemoglobin change was compared to iron in the diet. Similar results were obtained when absolute iron intake was compared on the basis of food consumption. In comparison to the control, protein carbonyl concentrations were significantly ( p < 0.05) higher in the FeSO₄ group but not with the ASP group. Supplementation with both sources of iron reduced the Enterobacteriaceae population in the gut microbiota of the rats. A higher relative abundance of bacteria from the phylum Verrucomicrobia was also observed with the highest dose of ASP. Iron-enriched A. oryzae with 60% relative bioavailability of FeSO₄ did not show any signs of adverse effects after 14 days of iron supplementation. Future human studies are needed to understand the ASP detailed effect on gut microbiota.

Comparison of the effects of dietary single and multi-probiotics on growth, non-specific immune responses and disease resistance in starry flounder, Platichthys stellatus

An 8-week feeding trial was conducted to evaluate the effects of dietary probiotics on growth performance and non-specific immune responses in starry flounder, Platichthys stellatus. Fish averaging 46.5 ± 0.65 g (mean ± SD) were fed one of the six experimental diets; one control (Cont), and five other diets were prepared by supplementing single-probiotics 1 (Bacillus subtilis; SP₁, 2 × 10⁹ CFU kg^-1 diet), single-probiotics 2 (Bacillus licheniformis; SP₂, 2 × 10⁹ CFU kg^-1 diet), multi-probiotics 1 (Bacillus subtilis + Bacillus licheniformis; MP₁, 2 × 10⁹ CFU kg^-1 diet), multi-probiotics 2 (commercial probiotics; Bacillus subtills + Bacillus licheniformis + Paenibacillus polymyxa + Aspergillus oryzae + Saccharomyces cerevisiae; MP₂, 2 × 10⁹ CFU kg^-1 diet) and oxytetracycline (OTC) at 5 g OTC kg^-1 diet. At the end of 8 weeks feeding trial, weight gain (WG) and specific growth rate (SGR) of fish fed SP₁, MP₁ and MP₂ diets were significantly higher than those of fish fed control diet (P < 0.05). Superoxide dismutase (SOD) activity of fish fed MP₂ diet was significantly higher than those of fish fed OTC diet (P < 0.05). Nitro blue tetrazolium (NBT) activity and lysozyme activity of fish fed SP₁, MP₁ and MP₂ diets were significantly higher than those of fish fed OTC diet (P < 0.05). However, there was no significant difference among fish fed SP₁, SP₂, MP₁ and MP₂ diets. During the Edwardsiella tarda challenge test, the first mortality occurred on day 2. After the 14 days challenge test, cumulative survival rate of fish fed MP₁ and MP₂ diets were significantly higher than those of fish fed control diet (P < 0.05). However, there was no significant difference among fish fed SP₁, SP₂, MP₁, MP₂ and OTC diets in survival rate at the termination of the challenge test. Although there was little advantage in immunological parameters with fish fed MP diets, single and multi-probiotics were equally effective statistically. These results demonstrated that single or multi-probiotics had equal beneficial effect as an antibiotic replacer in terms of growth performance, non-specific immune responses and disease resistance in starry flounder.

Studies of the Toxicological Potential of Tripeptides (L-Valyl-L-prolyl-L-proline and L-lsoleucyl-L-prolyl-L-proline): VII. Micronucleus Test of Tripeptides-Containing Casein Hydrolysate and Lactobacillus helveticus-fermented Milk Powders in Rats and Mice

The objective of these in vivo experiments was to assess the mutagenic potential of tripeptides as reflected by the ability of the test compound to induce the formation of micronuclei in mouse polychromatic erythrocytes. The test agents used in these experiments were (1) powdered Aspergillus oryzae protease casein hydrolysate (CH) and (2) powdered Lactobacillus helveticus-fermented milk (FM). Both test agents contain two tripeptides, L-valyl-L-prolyl-L-proline (VPP) and L-isoleucyl-L-prolyl-L-proline (IPP). Male Sprague-Dawley rats (five per group) were administered doses of 0, 500, 1000, or 2000 mg (0, 3, 6, or 12 mg VPP plus IPP)/kg body weight (BW)/day CH by oral gavage for 2 days. Male CD-I mice (six per group) received a single oral gavage dose of 0, 500, 1000, or 2000 mg (0, 0.8, 1.6 or 3.3 mg VPP plus IPP)/kg BW of FM. Positive-control agents were cyclophosphamide (10 mg/kg, intraperitoneal [i.p.]) in rats and mitocycin C (2 mg/kg, i.p.) in mice. Twenty-four hours after the second dose of CH, or the dose of cyclophosphamide to rats, or FM or mitocycin C to mice, bone marrow cells were fixed and examined for the presence of polychromatic erythrocytes (PCEs) and the presence or absence of mi-cronucleated PCEs (MNPCEs). Administration of CH to rats and FM to mice produced neither changes in body weights nor signs of systemic toxicity. Similarly, neither CH nor FM caused statistically significant variations in the incidences of either PCEs or MNPCEs. Both positive-control agents caused unequivocal increases in the incidence of MNPCEs and cyclophosphamide significantly reduced the percent of rat erythrocytes appearing as PCEs. The results of these micronucleus assays conducted with either powdered CH or FM in rats and mice, respectively, show that neither form of the tripeptides possesses the potential to induce micronuclei formation in these rodent species.

Structural characterization, catalytic, kinetic and thermodynamic properties of Aspergillus oryzae tannase

Tannase (EC.3.1.1.20) from Aspergillus oryzae was purified using ammonium sulphate precipitation (75%), gel filtration chromatography through Sephadex G-100, and G-200. The purified enzyme was monomeric protein with a molecular mass of 106kDa. The activation energy for tannic acid hydrolysis was 32.6kJmol^-1 and its temperature quotient (Q₁₀) was 1.0. The pK_a1 and pK_a2 values of acidic and basic limbs of the active site residues were 4.6 and 6.4. The calculated values of thermodynamic parameters for tannic acid hydrolysis, were as follows: ΔH*=30.02kJmol^-1, ΔG*=59.75kJmol^-1 ΔS*=-95.90Jmol^-1K^-1, (ΔG*_E-S)=3.66kJmol^-1 and ΔG*_E-T -12.61kJmol^-1. The pure enzyme exhibited K_m, V_max and k_cat of 4.13mM, 3507Umgprotein^-1 and 551.4s^-1_. The calculated half-life time at 40, 45, 50, 55, 60, and 70°C was 955.15, 142.0, 30.28, 17.88, 8.23 and 2.95min, respectively. The thermodynamic parameters for irreversible thermal inactivation at different temperatures (40-70°C) were determined. The enzyme was activated by Ca²⁺, and Mg²⁺ while Hg²⁺, Fe²⁺, and Cu²⁺ strongly inhibited it. Hydrolysis of tannic acid by the pure enzyme indicated that gallic acid was the end-product.

Production of the natural iron chelator deferriferrichrysin from Aspergillus oryzae and evaluation as a novel food-grade antioxidant

BACKGROUND

Deferriferrichrysin (Dfcy) is a siderophore found in foods fermented by Aspergillus oryzae and is a promising candidate for an antioxidant food additive because of its high binding constant toward iron. However, the Dfcy concentration is typically low in foods and cultures.

RESULTS

We optimised culture conditions to improve Dfcy production to 2800 mg L(-1) from 22.5 mg L(-1) under typical conditions. Then, we evaluated the potential of Dfcy as a food additive by measuring its safety, stability, and antioxidant activity. Dfcy was sufficiently stable that over 90% remained after pasteurisation at 63 °C for 30 min at pH 3-11, or after sterilisation at 120 °C for 4 min at pH 4-6. Dfcy showed high antioxidant activity in an oil-in-water model, where inhibition of lipid oxidation was measured by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) assays. Dfcy decreased PV and TBARS by 83% and 75%, respectively. Antioxidant activity of Dfcy was equal to or higher than that of the synthetic chelator EDTA.

CONCLUSION

Our study provides the first practical method for production of Dfcy. Dfcy can be a novel food-grade antioxidant and the first natural alternative to the synthesised iron chelator EDTA. © 2015 Society of Chemical Industry.

Metabolomic Profiles of Aspergillus oryzae and Bacillus amyloliquefaciens During Rice Koji Fermentation

Rice koji, used early in the manufacturing process for many fermented foods, produces diverse metabolites and enzymes during fermentation. Using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), ultrahigh-performance liquid chromatography linear trap quadrupole ion trap tandem mass spectrometry (UHPLC-LTQ-IT-MS/MS), and multivariate analysis we generated the metabolite profiles of rice koji produced by fermentation with Aspergillus oryzae (RK_AO) or Bacillus amyloliquefaciens (RK_BA) for different durations. Two principal components of the metabolomic data distinguished the rice koji samples according to their fermenter species and fermentation time. Several enzymes secreted by the fermenter species, including α-amylase, protease, and β-glucosidase, were assayed to identify differences in expression levels. This approach revealed that carbohydrate metabolism, serine-derived amino acids, and fatty acids were associated with rice koji fermentation by A. oryzae, whereas aromatic and branched chain amino acids, flavonoids, and lysophospholipids were more typical in rice koji fermentation by B. amyloliquefaciens. Antioxidant activity was significantly higher for RK_BA than for RK_AO, as were the abundances of flavonoids, including tricin, tricin glycosides, apigenin glycosides, and chrysoeriol glycosides. In summary, we have used MS-based metabolomics and enzyme activity assays to evaluate the effects of using different microbial species and fermentation times on the nutritional profile of rice koji.

Antiviral and Cytotoxic Isocoumarin Derivatives from an Endophytic Fungus Aspergillus oryzae

Oryzaeins A-D (1-4), four new isocoumarin derivatives, along with five known ones (5-9) were isolated from solid cultures of an endophytic fungus Aspergillus oryzae. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data of related derivatives. Among them, compounds 1 and 2 represent the first examples of isocoumarins possessing an unusual 2-oxopropyl group and a rare 3-hydroxypropyl group. Compounds 1 and 2 displayed moderate anti-tobacco mosaic virus activities with inhibition rates of 28.4% and 30.6%, respectively, at the concentration of 20 µM. The new compounds showed moderate inhibitory activities against several human tumor cell lines with IC50 values in the range of 2.8-8.8 µM. Supporting information available online at http://www.thieme-connect.de/products.

Flavourzyme, an Enzyme Preparation with Industrial Relevance: Automated Nine-Step Purification and Partial Characterization of Eight Enzymes

Flavourzyme is sold as a peptidase preparation from Aspergillus oryzae. The enzyme preparation is widely and diversely used for protein hydrolysis in industrial and research applications. However, detailed information about the composition of this mixture is still missing due to the complexity. The present study identified eight key enzymes by mass spectrometry and partially by activity staining on native polyacrylamide gels or gel zymography. The eight enzymes identified were two aminopeptidases, two dipeptidyl peptidases, three endopeptidases, and one α-amylase from the A. oryzae strain ATCC 42149/RIB 40 (yellow koji mold). Various specific marker substrates for these Flavourzyme enzymes were ascertained. An automated, time-saving nine-step protocol for the purification of all eight enzymes within 7 h was designed. Finally, the purified Flavourzyme enzymes were biochemically characterized with regard to pH and temperature profiles and molecular sizes.

Laccase immobilization over multi-walled carbon nanotubes: Kinetic, thermodynamic and stability studies

The biocatalytic performance of immobilized enzyme systems depends mostly on the intrinsic properties of both biomolecule and support, immobilization technique and immobilization conditions. Multi-walled carbon nanotubes (MWCNTs) possess unique features for enzyme immobilization by adsorption. Enhanced catalytic activity and stability can be achieved by optimization of the immobilization conditions and by investigating the effect of operational parameters. Laccase was immobilized over MWCNTs by adsorption. The hybrid material was characterized by Fourier transformed infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM, respectively). The effect of different operational conditions (contact time, enzyme concentration and pH) on laccase immobilization was investigated. Optimized conditions were used for thermal stability, kinetic, and storage and operational stability studies. The optimal immobilization conditions for a laccase concentration of 3.75μL/mL were a pH of 9.0 and a contact time of 30min (522 Ulac/gcarrier). A decrease in the thermal stability of laccase was observed after immobilization. Changes in ΔS and ΔH of deactivation were found for the immobilized enzyme. The Michaelis-Menten kinetic constant was higher for laccase/MWCNT system than for free laccase. Immobilized laccase maintained (or even increased) its catalytic performance up to nine cycles of utilization and revealed long-term storage stability.

Dietary supplementation with Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus oryzae enhance immunity and disease resistance against Aeromonas hydrophila and Streptococcus iniae infection in juvenile tilapia Oreochromis niloticus

A feeding trial was conducted to investigate the effects of dietary administration of probiotic with Bacillus subtilis, Aspergillus oryzae and Saccharomyces cerevisiae on growth, innate immune response, Hemato-immunological parameters and disease resistance of Nile tilapia, Oreochromis niloticus. Animals were distributed in three equal groups, each of five replicates and received one of the following experimental diets for four weeks: Control, non-supplemented diet; 5 g kg(-1) probiotic mixture (B. subtilis 1.5 × 10(9) CFU g(-1), S. cerevisiae 10(9) CFU g(-1) and A. oryzae 2 × 10(9) CFU g(-1)); and 10 g kg(-1) probiotic mixture (B. subtilis 3.0 × 10(9) CFU g(-1), S. cerevisiae 2.0 × 10(9) CFU g(-1) and A. oryzae 4.0 × 10(9) CFU g(-1)). The respiratory burst activity, white blood cells and hematological parameters were evaluated after four, five and six weeks of feeding. At the end of the growth trial, fish were sampled for intestinal microbiology and challenged by intraperitoneal injection of LD50 concentration of Aeromonas hydrophila and Streptococcus iniae. Mortality was recorded for the following 3 weeks. Results showed that administration of the probiotic had no significant effect on the growth rates of Nile tilapias, although the fish fed probiotics had better feed conversion. Respiratory burst activity, erythrocyte fragility and levels of white blood cells were significantly improved in tilapias fed diet supplemented with probiotic levels (P < 0.05), which may exhibit up-regulating effects on tilapia immune parameters. The cumulative mortality after A. hydrophila and S. iniae challenge decreased in tilapias fed with probiotic (P < 0.05). The present study demonstrated the potential of B. subtilis, S. cerevisiae and A. oryzae combined as beneficial dietary probiotic in juvenile O. niloticus.

Structural analysis of cerebrosides from Aspergillus fungi: the existence of galactosylceramide in A. oryzae

Glucosylceramide and galactosylceramide were detected in three Aspergillus species: Aspergillus oryzae, Aspergillus sojae and Aspergillus. awamori, using borate-coated TLC. The cerebrosides from A. oryzae were further purified by ion exchange and iatrobeads column chromatographies with or without borate, and determined the composition of sugar, fatty acid and sphingoid base by GC/MS, MALDI-TOF/MS and (1)H-NMR. We identified them as β-glucosylceramide and β-galactosylceramide. The ceramide moiety of both cerebrosides consisted mainly of 2-hydroxystearic acid and either 9-methyl-octadeca-4, 8-sphingadienine or octadeca-4, 8-sphingadienine. To our knowledge, this is the first study to provide evidence for the presence of β-galactosylceramide in A. oryzae.

Non-aflatoxigenicity of commercial Aspergillus oryzae strains due to genetic defects compared to aflatoxigenic Aspergillus flavus

Aspergillus oryzae is generally recognized as safe, but it is closely related to A. flavus in morphology and genetic characteristics. In this study, we tested the aflatoxigenicity and genetic analysis of nine commercial A. oryzae strains that were used in Korean soybean fermented products. Cultural and HPLC analyses showed that none of the commercial strains produced detectable amount of aflatoxins. According to the molecular analysis of 17 genes in the aflatoxin (AF) biosynthetic pathway, the commercial strains could be classified into three groups. The group I strains contained all the 17 AF biosynthetic genes tested in this study; the group II strains deleted nine AF biosynthetic genes and possessed eight genes, including aflG, aflI, aflK, aflL, aflM, aflO, aflP, and aflQ; the group III strains only had six AF biosynthetic genes, including aflG, aflI, aflK, aflO, aflP, and aflQ. With the reverse transcription polymerase chain reaction, the group I A. oryzae strains showed no expression of aflG, aflQ and/or aflM genes, which resulted in the lack of AF-producing ability. Group II and group III strains could not produce AF owing to the deletion of more than half of the AF biosynthetic genes. In addition, the sequence data of polyketide synthase A (pksA) of group I strains of A. oryzae showed that there were three point mutations (two silent mutations and one missense mutation) compared with aflatoxigenic A. flavus used as the positive control in this study.

Biochemical characterization of Aspergillus oryzae native tannase and the recombinant enzyme expressed in Pichia pastoris

In this study, the biochemical properties of the recombinant tannase from Aspegillus oryzae were compared with those of the native enzyme. Extracellular native tannase was purified from a commercial enzyme source. Recombinant tannase highly expressed in Pichia pastoris was prepared as an active extracellular protein. Purified native and recombinant tannases produced smeared bands with apparent molecular masses of 45-80 kDa and 45-75 kDa, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After N-deglycosylation, the native enzyme yielded molecular masses of 33 kDa and 30 kDa, whereas the recombinant enzyme yielded molecular masses of 34 kDa and 30 kDa. Purified native and recombinant tannases had an optimum pH of 4.0-5.0 and 5.0, respectively, and were stable up to 40°C. After N-deglycosylation, both enzymes exhibited reduced thermostability. Catalytic efficiencies of both purified enzymes were greater with natural substrates, such as (-)-catechin, (-)-epicatechin, and (-)-epigallocatechin gallates, than those with synthetic substrates, such as methyl, ethyl, and propyl gallates. However, there were no activities against the methyl esters of ferulic, p-coumaric, caffeic, and sinapic acids, which indicate feruloyl esterase activity, or the ethyl, propyl, and butyl esters of 4-hydroxybenzoic acid, which indicate paraben hydrolase activity.

Deglycosylation induces extensive dynamics changes in α-amylase revealed by hydrogen/deuterium exchange mass spectrometry

RATIONALE

N-Linked glycosylation plays important roles in modulating protein structure and function. The direct impact of the modification on protein conformation is not yet well understood.

METHODS

Here we probed the dynamic changes following Endo H trimming of high mannose glycans in α-amylase by means of amide hydrogen/deuterium exchange mass spectrometry.

RESULTS

The results revealed that deglycosylation elicited extensive alterations in backbone dynamics, affecting regions both adjacent to and distal from the glycosylation site.

CONCLUSIONS

The overall exchange rate is reduced in the glycosylated state, which indicates rigidity enhancement due to the attached carbohydrates.

Bioremediation of direct dyes in simulated textile effluents by a paramorphogenic form of Aspergillus oryzae

Azo dyes are extensively used for coloring textiles, paper, food, leather, drinks, pharmaceutical products, cosmetics and inks. The textile industry consumes the largest amount of azo dyes, and it is estimated that approximately 10-15% of dyes used for coloring textiles may be lost in waste streams. Almost all azo dyes are synthetic and resist biodegradation, however, they can readily be reduced by a number of chemical and biological reducing systems. Biological treatment has advantages over physical and chemical methods due to lower costs and minimal environmental effect. This research focuses on the utilization of Aspergillus oryzae to remove some types of azo dyes from aqueous solutions. The fungus, physically induced in its paramorphogenic form (called 'pellets'), was used in the dye biosorption studies with both non-autoclaved and autoclaved hyphae, at different pH values. The goals were the removal of dyes by biosorption and the decrease of their toxicity. The dyes used were Direct Red 23 and Direct Violet 51. Their spectral stability (325-700 nm) was analyzed at different pH values (2.50, 4.50 and 6.50). The best biosorptive pH value and the toxicity limit, (which is given by the lethal concentration (LC(100)), were then determined. Each dye showed the same spectrum at different pH values. The best biosorptive pH was 2.50, for both non- autoclaved and autoclaved hyphae of A. oryzae. The toxicity level of the dyes was determined using the Trimmed Spearman-Karber Method, with Daphnia similis in all bioassays. The Direct Violet 51 (LC(100) 400 mg · mL(-1)) was found to be the most toxic dye, followed by the Direct Red 23 (LC(100) 900 mg · mL(-1)). The toxicity bioassays for each dye have shown that it is possible to decrease the toxicity level to zero by adding a small quantity of biomass from A. oryzae in its paramorphogenic form. The autoclaved biomass had a higher biosorptive capacity for the dye than the non-autoclaved biomass. The results show that bioremediation occurs with A. oryzae in its paramorphogenic form, and it can be used as a biosorptive substrate for treatment of industrial waste water containing azo dyes.

Competitive biosorption of Acid Blue 25 and Acid Red 337 onto unmodified and CDAB-modified biomass of Aspergillus oryzae

The performance of unmodified and cetyldimethylethyl ammonium bromide (CDAB) modified nonviable Aspergillus oryzae for removal of Acid Blue 25 (AB 25) and Acid Red 337 (AR 337) was investigated in single and binary systems. In single system, the biosorption capacities of CDAB-modified biosorbent reached 160.36 and 280.39mg g(-1) for AB 25 and AR 337, respectively, which were 1.52 and 1.66 times higher than that of unmodified biosorbent. In binary system, the biosorption capacities of unmodified and CDAB-modified biosorbents for both dyes decreased significantly compared to that in single system. Relative competitiveness analysis demonstrated that there existed critical initial concentration ratio which determined the predominance of dyes during biosorption process. The biosorption of AB 25 was found to be in dominant position at initial concentration ratio of [AB 25]/[AR 337] above 0.63. Kinetic analysis indicated that intraparticle diffusion was the limiting step for biosorption of two dyes onto biosorbents.

Asporyergosterol, a new steroid from an algicolous isolate of Aspergillus oryzae

Asporyergosterol (1), a new steroid with an E double bond between C-17 and C-20, was identified from the culture extracts of Aspergillus oryzae, an endophytic fungus isolated from the marine red alga Heterosiphonia japonica. Moreover, four known steroids including (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (2), (22E,24R)-3beta-hydroxyergosta-5,8,22-trien-7-one (3), (22E,24R)-ergosta-7,22-dien-3beta,5alpha,6beta-triol (4), and (22E,24R)-5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (5) were isolated. Structures of these compounds were unambiguously established by spectroscopic techniques and by comparison with literature values. All the isolates exhibited low activity to modulate acetylcholinesterase (AChE).

Characterization of galactosyl derivatives obtained by transgalactosylation of lactose and different polyols using immobilized beta-galactosidase from Aspergillus oryzae

The synthesis of novel galactosides is interesting because of their important role in several biological processes. Their properties greatly depend upon the configuration and type of galactoside. Therefore, to study biological activity, it is essential to elucidate the structure of the products. Glycosidases are capable of catalyzing glycosidic linkages with absolute stereoselectivity of the anomeric center. We report the enzymatic synthesis of galactosyl-ethylene glycol, galactosyl-glycerol, and galactosyl-erythritol by immobilized beta-galactosidase from Aspegillus oryzae. The obtained galactosides were isolated and fully characterized by an extensive nuclear magnetic resonance (NMR) study. Complete structure elucidation and full proton and carbon assignments were carried out using 1D ((1)H and (13)C) and 2D (gCOSY, TOCSY, multiplicity-edited gHSQC, and gHMBC) NMR experiments. The beta-galactosidase from A. oryzae showed a strong preference for primary alcohols. For galactosyl-glycerol and galactosyl-erythritol, this preference generated one and two chiral centers, respectively, and a mixture of stereoisomers was obtained as a consequence.

A biotechnological product and its potential as a new immunomodulator for treatment of animal phlebovirus infection: Punta Toro virus

Intracellular pathogens with widespread drug-resistance contribute substantially to the increasing rates in morbidity and mortality due to emerging and reemerging diseases. Thus, the development of new drugs, including those that can enhance the immune response, is urgently needed. The immunomodulator, P-MAPA, a proteinaceous aggregate of ammonium and magnesium phospholinoleate-palmitoleate anhydride derived from Aspergillus oryzae, have been shown to induce antitumor activities. The ability of this compound to elicit protective immunity against viral infections has not been fully explored. Here, we report findings on the use of P-MAPA as an antiviral agent in a mouse model of acute phleboviral (Punta Toro virus) disease. A dose administered i.p. 24h post-infectious challenge (100mg/kg dose of P-MAPA) was remarkably effective at preventing death due to Punta Toro virus infection. This dose also reduced systemic viral burden and liver discoloration assayed on day 3 of infection. Taken together, our findings indicate that non-specific immunotherapy with P-MAPA appears to be an effective treatment for blocking Punta Toro virus-induced disease and suggest that further exploration with other viral disease models is warranted.

Secretory expression of the non-secretory-type Lentinula edodes laccase by Aspergillus oryzae

The shiitake mushroom, Lentinula edodes, has an extracelluar secretory-type laccase, Lcc1, and a fruiting-body-accumulation-type laccase, Lcc4. We previously reported the production of Lcc1 by plant cells, but had difficulty producing Lcc4. Here, we report the production of Lcc1 and Lcc4 by Aspergillus oryzae and the extracellular secretory production of Lcc4 using a modified secretion signal peptide (SP) from Lcc1. Sp-Lcc4 produced by A. oryzae had biochemical activities similar to Lcc4 produced by L. edodes. Lcc1 did not react with beta-(3,4-dihydroxyphenol) alanine (DOPA), but Lcc4 from L. edodes and A. oryzae could oxidize DOPA. K(M) values for the substrates 2,2'-azino-di-(3-ethylbenzthiazolinsulfonate), 2,6-dimethoxyphenol, guaiacol, pyrogallol, and catechol were similar for Lcc4 and Sp-Lcc4. In conclusion, a non-secretory-type fungal laccase is secreted into the culture media with its original enzymatic properties by exploiting modified secretory signal peptide.

Isolation and characterization of an extracellular antimicrobial protein from Aspergillus oryzae

A 17 kDa antimicrobial protein was isolated from growth medium containing the filamentous fungus Aspergillus oryzae by extracting the supernatants from the culture media, ion exchange chromatography on CM-sepharose, and C18 reverse-phase high-performance liquid chromatography. This antimicrobial protein, which we considered to be an extracellular antimicrobial protein from A. oryzae (exAP-AO17), possessed antimicrobial activity but lacked hemolytic activity. The exAP-AO17 protein strongly inhibited pathogenic microbial strains, including pathogenic fungi, Fusarium moniliform var. subglutinans and Colletotrichum coccodes, and showed antibacterial activity against bacteria, including E. coli O157 and Staphylococcus aureus. To confirm that the protein acts as a regulation factor for extracellular secretion, we examined growth under varying conditions of N sources, C sources, ions, ambient pH, and stress. Various culture conditions were found to induce characteristic changes in the expression of protein synthesis as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Highly basic polypeptides were regulated by suppressing the ambient pH under acidic conditions and strongly induced under alkaline conditions, thus confirming that pH regulation is physiologically relevant. The expression of exAP-AO17 was upregulated by heat shock upon growth in the presence of NaCl. Automated Edman degradation showed that the N-terminal sequence of exAP-AO17 was NH 2-GLPGPAGAVGFAGKDQNM-. ExAP-AO17 showed partial sequence homology with a collagen belonging to the animal source. These results suggest that exAP-AO17 is an excellent candidate as a lead compound for the development of novel oral or other types of anti-infective agents.

Three-phase partitioning of alpha-galactosidase from fermented media of Aspergillus oryzae and comparison with conventional purification techniques

Simple, attractive and versatile technique, three-phase partitioning (TPP) was used to purify alpha-galactosidase from fermented media of Aspergillus oryzae. The various conditions required for attaining efficient purification of the alpha-galactosidase fractions were optimized. The addition of n-butanol, t-butanol, and isopropanol in the presence of ammonium sulfate pushes the protein out of the solution to form an interfacial precipitate layer between the lower aqueous and upper organic layers. The single step of three-phase partitioning, by saturating final concentration of ammonium sulfate (60%) with 1:1 t-butanol, gave activity recovery of 92% with 12-fold purification at second phase of TPP. The final purified enzyme after TPP showed considerable purification on SDS-PAGE with a molecular weight of 64 kDa. The enzyme after TPP showed improved activity in organic solvents. Results are compared with conventional established processes for the purification of alpha-galactosidase produced by Aspergillus oryzae and overall the proposed TPP technique resulted in 70% reduction of purification cost compared to conventional chromatographic protocols.

Carbohydrate binding specificity of a fucose-specific lectin from Aspergillus oryzae: a novel probe for core fucose

The alpha1,6-fucosyl residue (core fucose) of glycoproteins is widely distributed in mammalian tissues and is altered under pathological conditions. A probe that specifically detects core fucose is important for understanding the role of this oligosaccharide structure. Aleuria aurantia lectin (AAL) and Lens culimaris agglutinin-A (LCA) have been often used as carbohydrate probes for core fucose in glycoproteins. Here we show, by using surface plasmon resonance (SPR) analysis, that Aspergillus oryzae l-fucose-specific lectin (AOL) has strongest preference for the alpha1,6-fucosylated chain among alpha1,2-, alpha1,3-, alpha1,4-, and alpha1,6-fucosylated pyridylaminated (PA)-sugar chains. These results suggest that AOL is a novel probe for detecting core fucose in glycoproteins on the surface of animal cells. A comparison of the carbohydrate-binding specificity of AOL, AAL, and LCA by SPR showed that the irreversible binding of AOL to the alpha1,2-fucosylated PA-sugar chain (H antigen) relative to the alpha1,6-fucosylated chain was weaker than that of AAL, and that the interactions of AOL and AAL with alpha1,6-fucosylated glycopeptide (FGP), which is considered more similar to in vivo glycoproteins than PA-sugar chains, were similar to their interactions with the alpha1,6-fucosylated PA-sugar chain. Furthermore, positive staining of AOL, but not AAL, was completely abolished in the cultured embryo fibroblast (MEF) cells obtained from alpha1,6-fucosyltransferase (Fut8) knock-out mice, as assessed by cytological staining. Taken together, these results suggest that AOL is more suitable for detecting core fucose than AAL or LCA.

Effects of a dietary Aspergillus oryzae extract containing α-amylase activity on performance and carcass characteristics of finishing beef cattle

Three experiments were conducted to examine the effects of an Aspergillus oryzae extract containing alpha-amylase activity on performance and carcass characteristics of finishing beef cattle. In Exp. 1, 120 crossbred steers were used in a randomized complete block design to evaluate the effects of roughage source (alfalfa hay vs. cottonseed hulls) and supplemental alpha-amylase at 950 dextrinizing units (DU)/kg of DM. Significant roughage source x alpha-amylase interactions (P < 0.05) were observed for performance. In steers fed cottonseed hulls, supplemental alpha-amylase increased ADG through d 28 and 112 and tended (P < 0.15) to increase ADG in all other periods. The increases in ADG were related to increased DMI and efficiency of gain during the initial 28-d period but were primarily related to increased DMI as the feeding period progressed. Supplemental alpha-amylase increased (P = 0.02) the LM area across both roughage sources. In Exp. 2, 96 crossbred heifers were used in a randomized complete block design with a 2 x 3 factorial arrangement of treatments to evaluate the effects of corn processing (dry cracked vs. high moisture) and supplemental alpha-amylase concentration (0, 580, or 1,160 DU/kg of DM). Alpha-amylase supplementation increased DMI (P = 0.05) and ADG (P = 0.03) during the initial 28 d on feed and carcass-adjusted ADG (P = 0.04) across corn processing methods. Longissimus muscle area was greatest (quadratic effect, P = 0.04), and yield grade was least (quadratic effect, P = 0.02) in heifers fed 580 DU of alpha-amylase/kg of DM across corn processing methods. In Exp. 3, 56 crossbred steers were used in a randomized complete block design to evaluate the effects of supplemental alpha-amylase (930 DU/kg of DM) on performance when DMI was restricted to yield a programmed ADG. Alpha-amylase supplementation did not affect performance when DMI was restricted. We conclude that dietary alpha-amylase supplementation of finishing beef diets may result in increased ADG through increased DMI under certain dietary conditions and that further research is warranted to explain its mode of action and interactions with dietary ingredients.

Cloning and expression of 1,2-alpha-mannosidase gene (fmanIB) from filamentous fungus Aspergillus oryzae: in vivo visualization of the FmanIBp-GFP fusion protein

1,2-alpha-Mannosidase catalyzes the specific cleavage of 1,2-alpha-mannose residues from protein-linked N-glycan. In this study, a novel DNA sequence homologous to the authentic 1,2-alpha-mannosidase was cloned from a cDNA library prepared from solid-state cultured Aspergillus oryzae. The fmanIB cDNA consisted of 1530 nucleotides and encoded a protein of 510 amino acids in which all consensus motifs of the class I alpha-mannosidase were conserved. Expression of the full length of 1,2-alpha-mannosidase cDNA by the Aspergillus host, though it has rarely been done with other filamentous-fungal mannosidase, was successful with fmanIB and caused an increase in both intracellular and extracellular mannosidase activity. The expressed protein (FmanIBp) specifically hydrolyzed 1,2-alpha-mannobiose with maximal activity at a pH of 5.5 and a temperature of 45 degrees C. With Man(9)GlcNAc(2) as the substrate, Man(5)GlcNAc(2) finally accumulated while hydrolysis of the 1,2-alpha-mannose residue of the middle branch was rate-limiting. To examine the intracellular localization of the enzyme, a chimeric protein of FmanIBp with green fluorescent protein was constructed. It showed a dotted fluorescence pattern in the mycelia of Aspergillus, indicative of the localization in intracellular vesicles. Based on these enzymatic and microscopic results, we estimated that FmanIBp is a fungal substitute for the mammalian Golgi 1,2-alpha-mannosidase isozyme IB. This and our previous report on the presence of another ER-type mannosidase in A. oryzae (Yoshida et al., 2000) support the notion that the filamentous fungus has similar steps of N-linked glycochain trimming to those in mammalian cells.

Analysis of secreted proteins during conidial germination of Aspergillus oryzae RIB40

To broaden our understanding of extracellular proteins of Aspergillus oryzae at the conidial germination stage, analyses of the secreted proteins during germination were carried out. Taka-amylase A (TAA), glucoamylase (GLAA), and aspergillopepsin A (PEPA) were identified as the main products by peptide mass fingerprinting. TAA and PEPA were detected simultaneously with the formation of germ tubes. With the development of germination, the pH of the medium fell from 5.5 to 3.5. The secreted PEPA had a pro-sequence and likely shifted from 42 kDa to 41 kDa below pH 4.6, indicating that the precursor of PEPA was secreted and underwent pH-dependent processing. Furthermore, the 41 kDa protein was trapped by the addition of pepstatin A, the specific inhibitor of PEPA, suggesting that the maturation of pro-PEPA was a stepwise autoprocessing upon acidification of the medium and itself was an intermediate of the processing. It was implied that PEPA plays an important role at the early germination stage.

Production of toxic metabolites in Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei: justification of mycotoxin testing in food grade enzyme preparations derived from the three fungi

Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei are three important production organisms used in industrial fermentations. Several of the fungal secondary metabolites produced by selected strains of these three fungi are capable of eliciting toxicity in animals. Among those toxic substances are the well-known mycotoxins 3-nitropropionic acid and ochratoxin A. However, many others, such as kojic acid, may not be true mycotoxins. The production, extraction, chemical structure, and the toxicity (expressed as LD(50)) of these substances are reviewed. Production of toxic secondary metabolites in A. niger, A. oryzae, and T. reesei is strain-specific and environment-dependent. Considering all of the safety measures taken in the industrial production process, these three fungal species are safe to use. The recently revised JECFA specification for mycotoxins in food enzyme preparations is also discussed. The extent of mycotoxin tests in food enzyme preparations should be judged on a case-by-case basis, through a careful evaluation based on knowledge of taxonomy, biochemistry, and genetics. In many cases, the testing scope at the level of genus should be sufficient. In other cases, the scope can even be further narrowed based on scientific knowledge and assessment.

Bioprocess Monitoring Using Near-Infrared Spectroscopy

Near-infrared spectroscopy (NIR) is a nondestructive analytical technique that has been used for simultaneous prediction of the concentrations of several substrates, products and constructs in mixtures sampled from fermentation processes. In this chapter, we discuss applications of NIR for the monitoring of bioprocesses involving rice vinegar, compost, glycolipid, L-glutamic acid, lactic acid fermentation, mushroom cultivation, and Koji production. This includes detailed discussion of applications of NIR to process management of rice vinegar fermentation and compost fermentation. In the present study, absorbance at wavelengths between 400 and 2500 nm was measured at 2 nm intervals. To obtain calibration equations, multiple linear regression (MLR) was performed on NIR spectral data and conventional analysis values of a calibration sample set. To validate these calibration equations, they were used to calculate concentrations of a prediction sample set, which were then compared with concentrations measured by conventional methods. There was excellent agreement between the results of the conventional method and those of the NIR method, when both were used to analyze culture broth of rice vinegar fermentation and solid-state fermented compost. These results indicate that NIR is a useful method for monitoring and control of bioprocesses.

A novel heterofunctional epoxy-amino sepabeads for a new enzyme immobilization protocol: immobilization-stabilization of beta-galactosidase from Aspergillus oryzae

The properties of a new and commercially available amino-epoxy support (amino-epoxy-Sepabeads) have been compared to conventional epoxy supports to immobilize enzymes, using the beta-galactosidase from Aspergillus oryzae as a model enzyme. The new support has a layer of epoxy groups over a layer of ethylenediamine that is covalently bound to the support. This support has both a great anionic exchanger strength and a high density of epoxy groups. Epoxy supports require the physical adsorption of the proteins onto the support before the covalent binding of the enzyme to the epoxy groups. Using conventional supports the immobilization rate is slow, because the adsorption is of hydrophobic nature, and immobilization must be performed using high ionic strength (over 0.5 M sodium phosphate) and a support with a fairly hydrophobic nature. Using the new support, immobilization may be performed at moderately low ionic strength, it occurs very rapidly, and it is not necessary to use a hydrophobic support. Therefore, this support should be specially recommended for immobilization of enzymes that cannot be submitted to high ionic strength. Also, both supports may be expected to yield different orientations of the proteins on the support, and that may result in some advantages in specific cases. For example, the model enzyme became almost fully inactivated when using the conventional support, while it exhibited an almost intact activity after immobilization on the new support. Furthermore, enzyme stability was significantly improved by the immobilization on this support (by more than a 12-fold factor), suggesting the promotion of some multipoint covalent attachment between the enzyme and the support (in fact the enzyme adsorbed on an equivalent cationic support without epoxy groups was even slightly less stable than the soluble enzyme).

Water and glucose gradients in the substrate measured with NMR imaging during solid-state fermentation with Aspergillus oryzae

Gradients inside substrate particles cannot be prevented in solid-state fermentation. These gradients can have a strong effect on the physiology of the microorganisms but have hitherto received little attention in experimental studies. We report gradients in moisture and glucose content during cultivation of Aspergillus oryzae on membrane-covered wheat-dough slices that were calculated from (1)H-NMR images. We found that moisture gradients in the solid substrate remain small when evaporation is minimized. This is corroborated by predictions of a diffusion model. In contrast, strong glucose gradients developed. Glucose concentrations just below the fungal mat remained low due to high glucose uptake rates, but deeper in the matrix glucose accumulated to very high levels. Integration of the glucose profile gave an average concentration close to the measured average content. On the basis of published data, we expect that the glucose levels in the matrix cause a strong decrease in water activity. The results demonstrate that NMR can play an important role in quantitative analysis of water and glucose gradients at the particle level during solid-state fermentation, which is needed to improve our understanding of the response of fungi to this nonconventional fermentation environment.

Comparison of lysis methods and preparation protocols for one- and two-dimensional electrophoresis of Aspergillus oryzae intracellular proteins

Filamentous fungal fermentations are used to produce billions of dollars of biochemical and pharmaceutical products annually, yet are plagued by a number of poorly understood problems that would benefit from proteomic analysis. Unfortunately, few publications are available which describe extraction of filamentous fungal proteins for two-dimensional electrophoresis. The goal here was to develop protocols for extraction of fungal proteins, from both wild-type and a recombinant strain of the industrially important filamentous fungi Aspergillus oryzae, to be used for both one- and two-dimensional electrophoresis (1-DE and 2-DE). Because fungal cell walls are exceptionally resistant to fragmentation, four lysis protocols were tested: (i) boiling in strong alkali solution, (ii) boiling in Sodium dodecyl surfate (SDS), (iii) chemical lysis in Y-PER(R) reagent, and (iv) mechanical lysis via rapid agitation with glass beads in a Mini-BeadBeater(R). For both 1-DE and 2-DE, rapid agitation with glass beads was found to be the most efficient extraction method, yielding both mini- and large-format gels with little streaking or spot tailing, and proteins comprising a broad range of molecular weights and pI values.

Fluorescence polarization: analysis of carbohydrate-protein interaction

Fluorescence polarization has been widely used for the studies on the molecular motion in solution and has been applied to immunoassays for proteins, therapeutic drug monitoring in clinical pharmacy, and assays for environmentally toxic compounds. Because fluorescence polarization is most readily applicable to the kinetic analysis of the binding reaction between a substance having small molecular mass and a receptor molecule, this method is easily applied to the analysis of carbohydrate-lectin binding. In this tutorial Thematic Review, we briefly introduce the principles of fluorescence polarization and some applications of fluorescence polarization technique to glycobiology.

Stimulation of myelopoiesis in Listeria monocytogenes-infected mice by an aggregated polymer isolated from Aspergillus oryzae

In this work, we investigated the effects of the proteic aggregated polymer of magnesium ammonium phospholinoleate-palmitoleate anhydride (MAPA) isolated from Aspergillus oryzae on the growth and differentiation of bone marrow granulocyte-macrophage progenitor cells (CFU-GM) in Listeriamonocytogenes-infected mice. A significant reduction in the CFU-GM number was observed in the initial phase of infection with a sublethal dose of Listeria. Treatment of mice with 0.5, 2.0 and 5.0 mg/kg MAPA for 7 days prior to infection significantly stimulated myelopoiesis in a dose-dependent manner. Moreover, treatment with 0.5 and 5.0 mg/kg MAPA resulted in 30% and 40% cures of mice lethally infected with Listeria, respectively. MAPA added directly to the culture dishes hardly affected colony formation by bone marrow cells, suggesting an indirect effect ofthis compound on myelopoiesis in vivo. In summary, the data show that MAPA can modulate the CFU-GM generation and antibacterial resistance in listeriosis. As the ability of hematopoietic tissues to produce phagocytes is of particular significance to mediate resistance to Listeria, the promotion of bone marrow CFU-GM by MAPA may contribute to a rapid restoration of phagocyte numbers in infected sites, thus mitigating the course of infection.

Myelopoietic response in tumour-bearing mice by an aggregated polymer isolated from Aspergillus oryzae

The effects of magnesium ammonium phospholinoleate-palmitoleate anhydride (MAPA), a proteic aggregated polymer isolated from Aspergillus oryzae, on the growth and differentiation of granulocyte-macrophage progenitor cells (colony-forming unit-granulocyte-macrophage [CFU-GM]) in normal and Ehrlich ascites tumour-bearing mice were studied. Myelosuppression concomitant with increased numbers of spleen CFU-GM was observed in tumour-bearing mice. Treatment of these animals with MAPA (0.5-10 mg/kg) stimulated marrow myelopoiesis in a dose-dependent manner and reduced spleen colony formation. No changes were observed in total and differential marrow cell counts. The dose of 5.0 mg/kg MAPA, given prior or after tumour inoculation, was the optimal biologically active dose in tumour-bearing mice and this dose schedule also stimulated myelopoiesis in normal mice. MAPA significantly enhanced survival and concurrently reduced tumour growth in the peritoneal cavity. We propose that the modulatory effect of MAPA on the myelopoietic response may be related to its antitumour activity as a possible mechanism for regulation of granulocyte-macrophage production and expression of functional activities.

Transcript of a homolog of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus, was not detected in Aspergillus oryzae strains

Some strains of Aspergillus oryzae were shown to have homologs of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus. Transcription of an aflR homolog was examined in six strains of A. oryzae having the homologs, using polymerase chain reaction (PCR) coupled with reverse transcription. No PCR product was obtained when the RNA prepared from the A. oryzae strains cultivated under aflatoxin-producing condition was used as template for amplification of the aflR cDNA. By contrast, a PCR product of the expected size was obtained with RNA from A. parasiticus NIAH-26 processed by the same procedure. From genomic DNA of these strains, PCR products of the same size as above were obtained. Possible degradation of the aflR mRNA in the RNA preparation of the A. oryzae strains was negligible, because the calmodulin transcript was detected by PCR from the same RNA samples. Thus, the aflR homologs in the non-aflatoxigenic A. oryzae strains examined are not expressed even under aflatoxin-producing condition.

Localization of a phosphatidylglycerol/phosphatidylinositol transfer protein in Aspergillus oryzae

The subcellular localization of the phosphatidylglycerol/phosphatidylinositol transfer protein (PG/PI-TP) of Aspergillus oryzae was investigated using Western blot analysis of the cell protein extracts, a cellular membrane fractionation technique, and transmission electron microscopy. The PG/PI-TP, as detected by Western blot analysis with a specific immune serum, was found to be mainly cytoplasmic and partly associated with intracellular membranes. A fractionation experiment was conducted after homogenization of the filamentous fungus mycelium. The endoplasmic reticulum, Golgi-like vesicles, and the plasma membrane were separated by isopycnic ultracentrifugation on a sucrose gradient, and our data revealed that the immunodetected PG/PI-TP was only associated with the Golgi-like apparatus. All these results were documented by electron microscopy and indicate here for the first time that there exists a specific phospholipid transfer protein in a filamentous fungus that is localized in the cytoplasm and associated with Golgi-like vesicles.

Utilization of the TEF1-alpha gene (TEF1) promoter for expression of polygalacturonase genes, pgaA and pgaB, in Aspergillus oryzae

For the development of an efficient gene expression system in a shoyu koji mold Aspergillus oryzae KBN616, the TEF1 gene, encoding translation-elongation factor 1 alpha, was cloned from the same strain and used for expression of polygalacturonase genes. The TEF1 gene comprised 1647 bp with three introns. The TEF1-alpha protein consisted of 460 amino acids possessing high identify to other fungal TEF proteins. Two nucleotide sequences homologous to the upstream activation sequence, characterized for the ribosomal protein genes in Saccharomyces cerevisiae, as well as the pyrimidine-rich sequences were present in the TEF1 gene promoter region, suggesting that the A, oryzae TEF1 gene has a strong promoter activity. Two expression vectors, pTFGA300 and pTFGB200 for production of polygalacturonases A and B respectively, were constructed by using the TEF1 gene promoter. A polygalacturonase (PGB) gene cloned from the same strain comprised 1226 bp with two introns and encoded a protein of 367 amino acids with high similarity to other fungal polygalacturonases. PGA and PGB were secreted at approximately 100 mg/l in glucose medium and purified to homogeneity. PGA had a molecular mass of 41 kDa, a pH optimum of 5.0 and temperature optimum of 45 degrees C. PGB had a molecular mass of 39 kDa, a pH optimum of 5.0 and temperature optimum of 55 degrees C.

Alkaline serine proteinase: a major allergen of Aspergillus oryzae and its cross-reactivity with Penicillium citrinum

BACKGROUND

Aspergillus species are common indoor airborne fungi and have been considered as causative agents of human allergic disorders. However, allergens of different Aspergillus species have not been effectively characterized. The object of this study was to identify and characterize IgE-binding components of Aspergillus oryzae.

METHODS

Allergens of A. oryzae were identified by immunoblot analysis using sera from asthmatic patients. The N-terminal amino acid sequences of allergens thus identified were determined by Edman degradation. The antigenic and the allergenic cross-reactivities between allergens of different fungi were analyzed by immunoblotting and immunoblot inhibition analysis, respectively, using a monoclonal antibody (MoAb) 55A against the 33-kD major allergen of Penicillium citrinum and a mixture of IgE-containing asthmatic serum samples.

RESULTS

Thirteen components of A. oryzae ranging in apparent molecular weight from 16 to 42 kD react with IgE antibodies. A 34-kD component that showed intense IgE-binding reactivity and was detectable in the highest frequency in our asthmatic serum samples tested was considered a major allergen of A. oryzae. The 34-kD component also reacted with MoAb 55A. Results from immunoblot inhibition studies also demonstrated the IgE cross-reactivity between the 34-kD major allergens of A. oryzae and P. citrinum. In addition, the sequence of the N-terminal 18 amino acid residues of the 34-kD major allergen of A. oryzae was found to be identical to that of the alkaline serine proteinase from the same Aspergillus species.

CONCLUSION

The 34-kD major allergen of A. oryzae is an alkaline serine proteinase. There is IgE cross-reactivity between the major serine proteinase allergens of A. oryzae and P. citrinum.

Purification and characterization of a novel specific phosphatidylglycerol-phosphatidylinositol transfer protein with high activity from Aspergillus oryzae

A novel phospholipid transfer protein has been purified to homogeneity 406-fold from the filamentous fungus Aspergillus oryzae. The successive steps of purification comprised ultrafiltration, gel filtration on Sephadex G-75, ion exchange chromatographies on DEAE-Sepharose and Mono Q. The active protein is a monomer with a molecular mass of 19,000, estimated from SDS electrophoresis, amino acid composition as well as gel filtration. The isoelectric point is 4.8. The amino acid composition is characterized by a high amount of Gly, Leu, Ser, Asx and Glx residues and 4 Cys residues. N-terminal sequence was determined and compared with M. mucedo sequence. The purified protein was found to transfer preferentially phosphatidylglycerol and phosphatidylinositol over phosphatidylcholine > phosphatidylethanolamine > phosphatidylserine and no phosphatidic acid. Optimal temperature for in vitro transfer was 25-30 degrees C and optimal pH 4-7. Heating protein at 100 degrees C does not inactivate protein whereas a denaturation with urea is irreversible.

Formation of oligosaccharides from lactitol by Aspergillus oryzae beta-D-galactosidase

Six oligosaccharides were first formed from lactitol by a transgalactosylation reaction catalyzed by Aspergillus oryzae beta-D-galactosidase. From the results of methylation analysis, MS, and 1H- and 13C-NMR studies, it was concluded that these oligosaccharides are O-beta-D-galactopyranosyl-(1----4)-O-beta-D-galactopyranosyl-(1----4)-D- glucitol, O-beta-D-galactopyranosyl-(1----3)-O-beta-D-galactopyranosyl-(1----4)-D- glucitol, O-beta-D-galactopyranosyl-(1----4)-[O-beta-D-galactopyranosyl-(1----6)]- D- glucitol, O-beta-D-galactopyranosyl-(1----6)-O-beta-D-galactopyranosyl-(1---4)- glucitol, O-beta-D-galactopyranosyl-(1----4)-[O-beta-D-galactopyranosyl- (1----5)]-D-glucitol, and O-beta-D-galactopyranosyl-(1----4)-[O-beta-D-galactopyranosyl-(1----1)]- D-glucitol. The last three are newly observed oligosaccharides.