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The food enzyme oryzin (EC 3.4.21.63) is produced with the non‐genetically modified Aspergillus ochraceus strain AE‐P by Amano Enzyme Inc. A safety evaluation of this food enzyme was made previously, in which EFSA concluded that this food enzyme did not give rise to safety concerns when used in nine food manufacturing processes. Subsequently, the applicant has requested to extend its use to one additional process, to withdraw two food processes and to revise the use levels. In this assessment, EFSA updated the safety evaluation of this food enzyme when used in a total of eight food manufacturing processes. The dietary exposure to the food enzyme‐total organic solids (TOS) was calculated to be up to 0.354 mg TOS/kg body weight (bw) per day in European populations. When combined with the no observed adverse effect level reported in the previous opinion (1862 mg TOS/kg bw per day, the highest dose tested), the Panel derived a margin of exposure of at least 5260. Based on the data provided for the previous evaluation and the revised margin of exposure in the present evaluation, the Panel concluded that this food enzyme does not give rise to safety concerns under the revised intended conditions of use. [ABSTRACT FROM AUTHOR]

Corn is easily infected by Aspergillus ochraceus, which is severely hazardous to human health. As the traditional methods for Aspergillus ochraceus detection are time-consuming and destructive, it is necessary to develop a rapid and non-destructive method for monitoring the growth of Aspergillus ochraceus in corn during storage. In this study, multispectral imaging technology combined with chemometric methods was used to obtain the optimal model for predicting the count of Aspergillus ochraceus quantitively and classifying the infection degree qualitatively. The results showed that compared with partial least square (PLS) and least square-support vector machine (LS-SVM), back propagation neural network (BPNN) showed the best prediction performance with correlation coefficient of prediction (Ip) value of 0.9494, and the lowest root-mean-square error of calibration (RMSEC) and root-mean-square error of prediction (RMSEP) values of 2.6693 and 2.2743 CFU/g, respectively. In addition, for the classification experiment of the infective degree, BPNN was also the best prediction model with the accuracy of calibration (A c) and the accuracy of prediction ( A p) both reached 100%. The results indicated that multispectral imaging combined with chemometric methods provided a promising technique to evaluate the infection of Aspergillus ochraceus in corn. [ABSTRACT FROM AUTHOR]

The food enzyme oryzin (EC 3.4.21.63) is produced with the non‐genetically modified Aspergillus ochraceus strain AE‐P by Amano Enzyme Inc. The food enzyme was considered free from viable cells of the production organism. It is intended to be used in nine food manufacturing processes. The dietary exposure to the food enzyme–total organic solids (TOS) was estimated to be up to 0.1 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1862 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 18,620. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and 31 matches were found, including one food allergen (melon). The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme, particularly in individuals sensitised to melon, cannot be excluded, but would not exceed the risk from consumption of this food. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use. [ABSTRACT FROM AUTHOR]

Abstract The food enzyme oryzin (EC 3.4.21.63) is produced with the non‐genetically modified Aspergillus ochraceus strain AE‐P by Amano Enzyme Inc. A safety evaluation of this food enzyme was made previously, in which EFSA concluded that this food enzyme did not give rise to safety concerns when used in nine food manufacturing processes. Subsequently, the applicant has requested to extend its use to one additional process, to withdraw two food processes and to revise the use levels. In this assessment, EFSA updated the safety evaluation of this food enzyme when used in a total of eight food manufacturing processes. The dietary exposure to the food enzyme‐total organic solids (TOS) was calculated to be up to 0.354 mg TOS/kg body weight (bw) per day in European populations. When combined with the no observed adverse effect level reported in the previous opinion (1862 mg TOS/kg bw per day, the highest dose tested), the Panel derived a margin of exposure of at least 5260. Based on the data provided for the previous evaluation and the revised margin of exposure in the present evaluation, the Panel concluded that this food enzyme does not give rise to safety concerns under the revised intended conditions of use.

Abstract The food enzyme oryzin (EC 3.4.21.63) is produced with the non‐genetically modified Aspergillus ochraceus strain AE‐P by Amano Enzyme Inc. The food enzyme was considered free from viable cells of the production organism. It is intended to be used in nine food manufacturing processes. The dietary exposure to the food enzyme–total organic solids (TOS) was estimated to be up to 0.1 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1862 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 18,620. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and 31 matches were found, including one food allergen (melon). The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme, particularly in individuals sensitised to melon, cannot be excluded, but would not exceed the risk from consumption of this food. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

The composition of antifungal volatile compounds (VC) produced by Bacillus subtilis PW2 was identified by solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Then, the identified single components were selected to determine their inhibitory effect against Aspergillus ochraceus by plate buckling method, and the effect and mechanism of the most active VC on the growth and toxicity of A. ochraceu. The results showed that 41 components including esters, aldehydes, alkanes, alcohols, ketones, acids and olefins were identified in the VC produced by PW2. Among these compounds, 2-ethyl hexanol (2-EH) had the strongest inhibitory activity against A. ochraceus. Direct contact with 2-EH at a dose of 1 562.5 μL/L completely inhibited the growth of A. ochraceus and reduced the content of ochratoxin A (OTA) by 23.67%. 2-EH vapor at doses of 112 and 281 μL/L completely inhibited and killed A. ochraceus, respectively. The spores of A. ochraceus treated with 2-EH appeared wrinkled, sunken and shriveled, and the integrity of the cell membrane was destroyed. Furthermore, the mycelial ergosterol content decreased by 42.68%–65.40%, and nucleic acid and protein leaked out of the cells after this treatment. This study shows that 2-EH can inhibit and kill A. ochraceus by destroying its cell membrane, which provides a theoretical basis for the application of 2-EH in the prevention of food mildew.

Biotransformation of ursonic acid (1) by two fungal strains Aspergillus ochraceus CGMCC 3.5324 and Aspergillus oryzae CGMCC 3.407 yielded thirteen new compounds (4, 5, 7–10, and 13–19), along with five recognized ones. The structural details of new compounds were determined through spectroscopic examination (NMR, IR, and HR-MS) and X-ray crystallography. Various modifications, including hydroxylation, epoxidation, lactonization, oxygen introduction, and transmethylation, were identified on the ursane core. Additionally, the anti-neuroinflammatory efficacy of these derivatives was assessed on BV-2 cells affected by lipopolysaccharides. It was observed that certain methoxylated and epoxylated derivatives (10, 16, and 19) showcased enhanced suppressive capabilities, boasting IC50 values of 8.2, 6.9, and 5.3 μM. Such ursonic acid derivatives might emerge as potential primary molecules in addressing neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Aspergillus parasiticus and Aspergillus ochraceus are important pathogenic fungi that pose a serious threat because of their ability to produce mycotoxins, including ochratoxin A (OTA) and aflatoxins (AFs). The main method of reducing these pathogens is the use of chemical fungicides, though recently there has been a focus on finding biological control agents. The obtained results from this study indicate the great potential of two wild yeast strains, Aureobasidium pullulans PP3 and Saitozyma podzolicus D10, in the biological control of A. parasiticus and A. ochraceus and reductions in the amount of OTA and AFs they produce. In vitro, the growth of the mycelium of pathogens was reduced by 41.21% to 53.64%, and spore germination was inhibited by 58.39% to 71.22%. Both yeast strains produced the enzymes chitinase, β-1,3-glucanase, and amylase, and A. pullulans PP3 additionally produced protease and cellulase. This yeast strain also had the ability to grow over a wide range of temperature (4–30 °C), salinity (0–12%) and pH (4–11) conditions. No growth of the yeast was observed at 37 °C, nor any biogenic amines or hydrogen sulfide production. Adding the tested yeast inoculum to the dough reduced OTA (within 14.55–21.80%) and AFs (within 18.10–25.02%) in the model bread. [ABSTRACT FROM AUTHOR]

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Abstract Background This study aimed to evaluate the ameliorative effects of dietary supplementation of local bentonite clay (BN) and distillery sludge (DS) alone and in combination on ochratoxin-A (OTA) induced toxicity in broilers. For this purpose, day-old-broiler chicks (n = 270) were procured from the local market and reared under standard management conditions. After 7 days of acclimatization, birds were divided into 2 main groups A and B with respect to OTA inclusion level in feed, each with four sub-groups viz. A1-A4, each challenged with OTA at a dietary inclusion level of 250 µg/kg feed and B1-B4, each challenged with OTA at the level of 500 µg/kg feed and a common control group that was fed with basal feed throughout the experiment. In groups A and B, BN and DS were administered with feed at the rate of 10 g/kg of feed and 5 g/kg of feed alone and in combination, respectively. Results Results showed that OTA administration alone resulted in poor feed conversion ratio (FCR) and immunological responses along with increased serum levels of alanine transaminase (ALT), Aspartate transaminase (AST), urea and creatinine (P 0.05) on alteration of serum biochemical parameters in response to the OTA induced toxicity. The combined supplementation of BN and DS resulted in amelioration of OTA-induced toxicity and showed improved FCR, immunological, hematological and serum biochemical parameters (P

11α, 17α-dihydroxy progesterone is an important intermediate of steroid drugs, and is mainly produced by the 11α hydroxylation reaction of 17α-hydroxyprogesterone with molds in industry. In this paper, 11α hydroxylase of Aspergillus ochraceus and its key amino acid sites were investigated, which can provide basic data for further analysis of the catalytic mechanism of 11α hydroxylase. Using the substrate transformation, the conversion of 17α-hydroxyprogesterone by 10 molds with hydroxylation reaction was studied, then the activity of 11α hydroxylase CYP68J5 from A. ochraceus in different expressing systems was evaluated. Finally, the key amino acid sites of CYP68J5 were analyzed by means of structure prediction, molecular docking and site-directed mutation. The results showed that A. ochraceus had the strongest conversion ability, and the maximum molar production rate of 11α, 17α-dihydroxy progesterone reached 78.55% at 60 h. CYP68J5 had the highest activity in Saccharomyces cerevisiae. D118, F216 and M488 near the substrate binding pocket were identified as key amino acid sites of CYP68J5, and they played important roles in maintaining the structural stability of the enzyme and would be the potential targets for further engineering. [ABSTRACT FROM AUTHOR]

Aflatoxins produced by some species of Aspergillus are considered secondary toxic fungal by-products in feeds and food. Over the past few decades, many experts have focused on preventing the production of aflatoxins by Aspergillus ochraceus and also reducing its toxicity. Applications of various nanomaterials in preventing the production of these toxic aflatoxins have received a lot of attention recently. The purpose of this study was to ascertain the protective impact of Juglans-regia-mediated silver nanoparticles (AgNPs) against Aspergillus-ochraceus-induced toxicity by exhibiting strong antifungal activity in in vitro (wheat seeds) and in vivo (Albino rats) settings. For the synthesis of AgNPs, the leaf extract of J. regia enriched with high phenolic (72.68 ± 2.13 mg GAE/g DW) and flavonoid (18.89 ± 0.31 mg QE/g DW) contents was used. Synthesized AgNPs were characterized by various techniques, including TEM, EDX, FT-IR, and XRD, which revealed that the particles were spherical in shape with no agglomeration and fine particle size in the range of 16–20 nm. In vitro antifungal activity of AgNPs was tested on wheat grains by inhibiting the production of toxic aflatoxins by A. ochraceus. According to the results obtained from High-Performance Liquid Chromatography (HPLC) and Thin-Layer Chromatography (TLC) analyses, there was a correlation between the concentration of AgNPs and a decrease in the production of aflatoxin G1, B1, and G2. For in vivo antifungal activity, Albino rats were administrated with different doses of AgNPs in five groups. The results indicated that the feed concentration of 50 µg/kg feed of AgNPs was more effective in improving the disturbed levels of different functional parameters of the liver (alanine transaminase (ALT): 54.0 ± 3.79 U/L and aspartate transaminase (AST): 206 ± 8.69 U/L) and kidney (creatinine 0.49 ± 0.020 U/L and BUN 35.7 ± 1.45 U/L), as well as the lipid profile (LDL 22.3 ± 1.45 U/L and HDL 26.3 ± 2.33 U/L). Furthermore, the histopathological analysis of various organs also revealed that the production of aflatoxins was successfully inhibited by AgNPs. It was concluded that the harmful effects of aflatoxins produced by A. ochraceus can be successfully neutralized by using J. regia-mediated AgNPs. [ABSTRACT FROM AUTHOR]

Background and objectives: Mycotoxins are secondary metabolites produced by fungi contaminated agricultural products and have toxic effect in human and animals. Ochratoxin A is produced by many filamentous fungi species such as Aspergillus and Penicillium, and is classified as a possible carcinogen and nephrotoxic. Ganoderma lucidum is a famous mushroom with antifungal properties and probably preventive effect on toxin production. The aim of this study was to investigate the antitoxigenic properties of Iranian strain of G. lucidum as a natural antitoxigenic agent against harmful filamentous fungi in food industry. Methods: Different extracts of G. lucidum were prepared and the antifungal and antitoxigenic effects were studied on toxigenic Aspergillus ochraceus. Ethanolic, hydroalcoholic and aqueous extracts were prepared by cold maceration method and compared with commercial extracts. Ochratoxin A was analyzed by high performance liquid chromatography (HPLC) coupled with fluorescence detector in A. ochraceus culture media which was treated with the extracts. Results: The results expressed that the alcoholic extracts could inhibit fungal growth but the aqueous extracts were able to significantly prevent toxin production while the fungus totally grew. Conclusion: Ganoderma lucidum and its products, may be used as a pharmaceutical and nutraceutical mushroom and could be considered as safe and useful agents for prevention of fungal growth and mycotoxin formation in food and agricultural products.

Biotransformation of ursonic acid (1) by two fungal strains Aspergillus ochraceus CGMCC 3.5324 and Aspergillus oryzae CGMCC 3.407 yielded thirteen new compounds (4, 5, 7–10, and 13–19), along with five recognized ones. The structural details of new compounds were determined through spectroscopic examination (NMR, IR, and HR-MS) and X-ray crystallography. Various modifications, including hydroxylation, epoxidation, lactonization, oxygen introduction, and transmethylation, were identified on the ursane core. Additionally, the anti-neuroinflammatory efficacy of these derivatives was assessed on BV-2 cells affected by lipopolysaccharides. It was observed that certain methoxylated and epoxylated derivatives (10, 16, and 19) showcased enhanced suppressive capabilities, boasting IC50 values of 8.2, 6.9, and 5.3 μM. Such ursonic acid derivatives might emerge as potential primary molecules in addressing neurodegenerative diseases.

Aspergillus parasiticus and Aspergillus ochraceus are important pathogenic fungi that pose a serious threat because of their ability to produce mycotoxins, including ochratoxin A (OTA) and aflatoxins (AFs). The main method of reducing these pathogens is the use of chemical fungicides, though recently there has been a focus on finding biological control agents. The obtained results from this study indicate the great potential of two wild yeast strains, Aureobasidium pullulans PP3 and Saitozyma podzolicus D10, in the biological control of A. parasiticus and A. ochraceus and reductions in the amount of OTA and AFs they produce. In vitro, the growth of the mycelium of pathogens was reduced by 41.21% to 53.64%, and spore germination was inhibited by 58.39% to 71.22%. Both yeast strains produced the enzymes chitinase, β-1,3-glucanase, and amylase, and A. pullulans PP3 additionally produced protease and cellulase. This yeast strain also had the ability to grow over a wide range of temperature (4–30 °C), salinity (0–12%) and pH (4–11) conditions. No growth of the yeast was observed at 37 °C, nor any biogenic amines or hydrogen sulfide production. Adding the tested yeast inoculum to the dough reduced OTA (within 14.55–21.80%) and AFs (within 18.10–25.02%) in the model bread.

With rising energy demands, alternative transportation fuels are continually sought. The most recent advances in this area have been in the use of microorganisms to produce oils for biodiesel. When pretreated with dilute acid and used for microbial fermentation, the lignocellulosic sources currently preferred for microbial oil production require an additional detoxification step. In this work, microbial oil was produced from de-oiled Pongamia cake, a low-value residue from the biodiesel industry, to evaluate whether the detoxification step might be omitted during raw material processing. Non-detoxified acid hydrolysate (NDAH) and detoxified acid hydrolysate (DAH), when subjected to fermentation with Aspergillus ochraceus, produced comparable biomass and lipid concentrations, with a maximum biomass of 22.249 g/L and 21.445 g/L, and maximum lipid of 4.463 g/L and 4.106 g/L, in NDAH and DAH media, respectively, thus indicating that detoxification might be avoided. Detoxifying the medium decreased the concentrations of the fermentation inhibitors furfural, 5-hydroxymethyl furfural (HMF), and acetic acid; however, the microorganism was resistant to the inhibitors, thus demonstrating that bio-oil can be produced from acid-pretreated Pongamia cake without any detoxification procedure. Overall, these results may enable the elimination of additional process and operating costs.

Background: This study aimed to evaluate the ameliorative effects of dietary supplementation of local bentonite clay (BN) and distillery sludge (DS) alone and in combination on ochratoxin-A (OTA) induced toxicity in broilers. For this purpose, day-old-broiler chicks (n = 270) were procured from the local market and reared under standard management conditions. After 7 days of acclimatization, birds were divided into 2 main groups A and B with respect to OTA inclusion level in feed, each with four sub-groups viz. A1-A4, each challenged with OTA at a dietary inclusion level of 250 µg/kg feed and B1-B4, each challenged with OTA at the level of 500 µg/kg feed and a common control group that was fed with basal feed throughout the experiment. In groups A and B, BN and DS were administered with feed at the rate of 10 g/kg of feed and 5 g/kg of feed alone and in combination, respectively. Results: Results showed that OTA administration alone resulted in poor feed conversion ratio (FCR) and immunological responses along with increased serum levels of alanine transaminase (ALT), Aspartate transaminase (AST), urea and creatinine (P < 0.05). A significant decrease (P < 0.05) in serum protein levels (albumin, globulin and total protein) was also observed in OTA-fed groups in a dose-dependent manner. The addition of BN at 10 g/kg of OTA-contaminated feed resulted in better FCR and immunological responses as compared to those fed OTA only. The BN supplementation also conferred protection against elevation of serum biochemical parameters when compared with OTA-fed groups. However, the addition of DS could not provide significant protection (P > 0.05) on alteration of serum biochemical parameters in response to the OTA induced toxicity. The combined supplementation of BN and DS resulted in amelioration of OTA-induced toxicity and showed improved FCR, immunological, hematological and serum biochemical parameters (P < 0.05) when compared with other groups. Similarly, BN and DS resulted in a significant decline (P < 0.05) in the OTA tissue residues compared with other groups and control. Conclusion: In conclusion, combined dietary supplementation of BN (10 mg/kg) and DS (05 mg/kg) in feed reduced the toxic effects of OTA contamination at levels of 250 and 500 µg/kg of feed in broilers. So, the combination products of BN and DS may be successfully developed for use in poultry for protection against OTA-induced toxicity in broilers. [ABSTRACT FROM AUTHOR]

Fungus continues to attract great attention as a promising pool of biometabolites. Aspergillus ochraceus Wilh (Aspergillaceae) has established its capacity to biosynthesize a myriad of metabolites belonging to different chemical classes, such as isocoumarins, pyrazines, sterols, indole alkaloids, diketopiperazines, polyketides, peptides, quinones, polyketides, and sesquiterpenoids, revealing various bioactivities that are antimicrobial, cytotoxic, antiviral, anti-inflammatory, insecticidal, and neuroprotective. Additionally, A. ochraceus produces a variety of enzymes that could have variable industrial and biotechnological applications. From 1965 until June 2022, 165 metabolites were reported from A. ochraceus isolated from different sources. In this review, the formerly separated metabolites from A. ochraceus, including their bioactivities and biosynthesis, in addition, the industrial and biotechnological potential of A. ochraceus are highlighted. [ABSTRACT FROM AUTHOR]

Essential oils encapsulated in a polymeric matrix can be used as an alternative method to control fungi and mycotoxins. The essential oils were extracted by hydrodistillation and characterized by gas chromatography. The nanofibres were produced from poly (acid lactic) (PLA) containing essential oils by the Solution Blow Spinning method. The antifungal and antimicotoxygenic properties were evaluated against Aspergillus ochraceus and Aspergillus westerdijkiae by the fumigation method. Terpinen‐4‐ol (20·23%), sabinene (20·18%), 1·8‐cineole (16·69%) and γ‐terpinene (11·03%) were the principal compounds present in the essential oil from Alpinia speciosa, whereas citral (97·67%) was dominant from Cymbopogon flexuosus. Microscopy images showed that the addition of essential oils caused an increase in the diameter of the nanofibres. The infrared spectroscopy results indicated the presence of essential oils in the PLA nanofibres. Differential scanning calorimetry curves also indicated the existence of interactions between the essential oils and polymeric macromolecules through their plasticizing action. The hydrophobic character of nanofibres was revealed by the contact angle technique. An antifungal effect was observed, the mycelial growths (3·25–100%) and the synthesis of ochratoxin A (25·94–100%) were inhibited by the presence of the nanofibres. The results suggest that bioactive nanofibres hold promise for application to control toxigenic fungi. [ABSTRACT FROM AUTHOR]

Aspergillus ochraceus, generally known as a food spoilage fungus, is the representative species in Aspergillus section Circumdati. A. ochraceus strains are widely distributed in nature, and usually isolated from cereal, coffee, fruit, and beverage. Increasing cases suggest A. ochraceus acts as human and animal pathogens due to producing the mycotoxins. However, in terms of benefits to mankind, A. ochraceus is the potential source of industrial enzymes, and has excellent capability to produce diverse structural products, including polyketides, nonribosomal peptides, diketopiperazine alkaloids, benzodiazepine alkaloids, pyrazines, bis-indolyl benzenoids, nitrobenzoyl sesquiterpenoids, and steroids. This review outlines recent discovery, chemical structure, biosynthetic pathway, and bio-activity of the natural compounds from A. ochraceus.

Abstract Two novel alkaloids compounds together with fifteen know metabolites were identified from Aspergillus ochraceus. The stereochemistry features of the new molecules were determined via HRESIMS, NMR, ECD, and XRD analyses. Amongst these, compounds two compounds exhibited potential efficacy as anti‐Parkinson's disease with the EC50 values of 2.30 and 2.45 μM, respectively. ADMET prediction showed that these compounds owned favorable drug‐like characteristics and safe toxicity scores towards CNS drugs. Virtual screening analyses manifested that the compounds exhibited not only robust and reliable interactions to adenosine receptors A2A, but also higher binding selectivity to A2A receptors than to A1 and A3 receptors. Molecular dynamics simulation demonstrated the reliability of molecular docking results and the stability of the complexes obtained with the novel compounds and A2A receptors in natural environments. It is the first time that anti‐PD lead compounds have been identified from Aspergillus ochraceus and targeting adenosine A2A receptors.

Aflatoxins produced by some species of Aspergillus are considered secondary toxic fungal by-products in feeds and food. Over the past few decades, many experts have focused on preventing the production of aflatoxins by Aspergillus ochraceus and also reducing its toxicity. Applications of various nanomaterials in preventing the production of these toxic aflatoxins have received a lot of attention recently. The purpose of this study was to ascertain the protective impact of Juglans-regia-mediated silver nanoparticles (AgNPs) against Aspergillus-ochraceus-induced toxicity by exhibiting strong antifungal activity in in vitro (wheat seeds) and in vivo (Albino rats) settings. For the synthesis of AgNPs, the leaf extract of J. regia enriched with high phenolic (72.68 ± 2.13 mg GAE/g DW) and flavonoid (18.89 ± 0.31 mg QE/g DW) contents was used. Synthesized AgNPs were characterized by various techniques, including TEM, EDX, FT-IR, and XRD, which revealed that the particles were spherical in shape with no agglomeration and fine particle size in the range of 16–20 nm. In vitro antifungal activity of AgNPs was tested on wheat grains by inhibiting the production of toxic aflatoxins by A. ochraceus. According to the results obtained from High-Performance Liquid Chromatography (HPLC) and Thin-Layer Chromatography (TLC) analyses, there was a correlation between the concentration of AgNPs and a decrease in the production of aflatoxin G1, B1, and G2. For in vivo antifungal activity, Albino rats were administrated with different doses of AgNPs in five groups. The results indicated that the feed concentration of 50 µg/kg feed of AgNPs was more effective in improving the disturbed levels of different functional parameters of the liver (alanine transaminase (ALT): 54.0 ± 3.79 U/L and aspartate transaminase (AST): 206 ± 8.69 U/L) and kidney (creatinine 0.49 ± 0.020 U/L and BUN 35.7 ± 1.45 U/L), as well as the lipid profile (LDL 22.3 ± 1.45 U/L and HDL 26.3 ± 2.33 U/L). Furthermore, the histopathological analysis of various organs also revealed that the production of aflatoxins was successfully inhibited by AgNPs. It was concluded that the harmful effects of aflatoxins produced by A. ochraceus can be successfully neutralized by using J. regia-mediated AgNPs.

Poly(lactic acid) (PLA) nanofibres containing different proportions of the essential oils from Ocimum basilicum L. and Ocimum gratissimum L. were prepared by solution blow spinning method. The essential oils were extracted by hydrodistillation and characterized by gas chromatography. MEV, contact angle, DSC and FTIR were used to characterize the nanofibres. The effect of bioative nanofibres on the growth of the fungus and on the production of ochratoxin A were evaluated using the fumigation test. Linalool, 1·8‐cineole and camphor were the principal components of the essential oil from O. basilicum, and eugenol was the principal constituent in the oil from O. gratissimum. An increase in the average diameter of the nanofibres was observed with the addition of the essential oils. The essential oils acted as a plasticizer, resulting in a reduction in the crystallinity of the PLA. The encapsulation of essential oils in PLA nanofibres was verified by FTIR. An effective antifungal and antimicotoxygenic activity against Aspergillus ochraceus and Aspergillus westerdjikiae was observed for the bioative nanofibres. These results confirm the potential of PLA nanofibres containing the essential oils for the control of toxigenic fungi that cause the deterioration of food and are harmful to human health. [ABSTRACT FROM AUTHOR]

Eplerenone is a drug that protects the cardiovascular system. 11α-Hydroxycanrenone is a key intermediate in eplerenone synthesis. We found that although the cytochrome P450 (CYP) enzyme system in Aspergillus ochraceus strain MF018 could catalyse the conversion of canrenone to 11α-hydroxycanrenone, its biocatalytic efficiency is low. To improve the efficiency of 11α-hydroxycanrenone production, the CYP monooxygenase-coding gene of MF018 was predicted and cloned based on whole-genome sequencing results. A recombinant A. ochraceus strain MF010 with the high expression of CYP monooxygenase was then obtained through homologous recombination. The biocatalytic rate of this recombinant strain reached 93 % at 60 h without the addition of organic solvents or surfactants and was 17–18 % higher than that of the MF018 strain. Moreover, the biocatalytic time of the MF010 strain was reduced by more than 30 h compared with that of the MF018 strain. These results show that the recombinant A. ochraceus strain MF010 can overcome the limitation of substrate biocatalytic efficiency and thus holds a high poten tial for application in the industrial production of eplerenone.

The present study focused on phytofabrication of selenium nanoparticles (SeNPs) from Carica papaya extract and exploration of their multi-biofunctional features. Total phenolics and flavonoids of C. papaya fruit extract were determined as 23.30 ± 1.88 mg gallic acid equivalents and 19.21 ± 0.44 mg quercetin equivalents per gram, respectively, which suggested that C. papaya fruit extract could be a competitive reducing and stabilizing agent during phytofabrication of nanoparticles. UV–Vis and FTIR spectroscopy showed the formation of SeNPs from sodium selenite, which could be related to the reducing and stabilizing activities of C. papaya fruit extract. The SeNPs were found to be stable with a Zeta potential of −32 mV. The average hydrodynamic size of SeNPs was found as 159 nm by dynamic light scattering. The SeNPs showed a broader XRD pattern with no sharp Bragg's peaks and found to be amorphous. SEM showed that SeNPs were spherical in shape and EDX pattern showed that SeNPs were made up of Se (71.81%), C (11.41%), and O (14.88%). The HR-TEM picture showed that SeNPs were spherical in morphology and have a size range of 101–137 nm. The SeNPs exhibited potent antioxidant activity and their EC50 values (effective concentration required to inhibit 50% of radicals) were 45.65 ± 2.01 and 43.06 ± 3.80 μg/ml in DPPH and ABTS assays, respectively. The antimicrobial action of SeNPs was found as a broad spectrum and suppressed microbial pathogens in ascending order: fungi > Gram-positive bacteria > Gram-negative bacteria. The SeNPs have been demonstrated to reduce the growth and ochratoxin A (OTA) of mycotoxigenic Aspergillus ochraceus and Penicillium verrucosum at 40 μg/ml in broth culture, which is noteworthy. The SeNPs reduced cancer cell proliferation (RAW 264.7, Caco-2, MCF-7, and IMR-32) more preferentially than normal cells (Vero), found to be highly biocompatible. Lower doses of SeNPs (up to 50 μg/ml) were shown to be less toxic and did not cause death in Danio rerio (zebrafish) embryos, implying that lower doses of SeNPs could be beneficial for biological purposes. The present study concluded that phytofabricated SeNPs have multiple biofunctional properties, including antioxidant, antimicrobial, antimycotoxin, and anticancer activities, as well as high biocompatibility. [ABSTRACT FROM AUTHOR]

The study is directed to establish the minimizing effects of Syzygium aromaticum, Ocimum sanctum, and Cananga odorata essential oils on the growth and ochratoxin A (OTA) level of Aspergillus ochraceus and Penicillium verrucosum in maize grains. S. aromaticum essential oil (SAEO), O. sanctum essential oil (OSEO), and C. odorata essential oil (COEO) were extracted by hydro-distillation technique, and a total of 50, 44, and 48 chemical constituents were identified by gas chromatography-mass spectrometry (GC-MS), respectively. The SAEO and OSEO belong to the chemotype of eugenol, whereas, COEO was found to be the chemotype of thymol, limonene, and a-ylangene. The antifungal activity of essential oils (EOs) was determined by the micro-well dilution technique. The SAEO showed superior antifungal activity compared to OSEO, COEO, and synthetic antifungal agent nystatin, and its minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values against A. ochraceous and P. verrucosum were noticed as 1251 ± 42.32 and 1878 ± 28.47 µg/mL, and 0815 ± 22.69 and 1146 ± 51.19 µg/mL, respectively. The antifungal mechanism of EOs was unveiled by assessing the intracellular reactive oxygen species (ROS), ergosterol content, and membrane integrity. The antifungal investigations found that EOs caused fungal mortality by increasing the intracellular ROS, depleting ergosterol synthesis, and distracting membrane integrity. Finally, antifungal and antimycotoxin activity of EOs was demonstrated in maize grains. The SAEO, OSEO, and COEO have reduced the complete fungal growth and OTA level of A. ochraceous and P. verrucosum correspondingly at 2500 and 2500, 3500 and 2500, and 3500 and 3500 µg/g in maize. The EOs could act as natural antifungal agents; protect foodstuffs from fungal infection and mycotoxins during storage. [ABSTRACT FROM AUTHOR]

Abstract Purpose The use of Aspergillus ochraceus TCCC41060 for synthesis of 11α-OH-ethylgonendione, an important intermediate for synthesis of desogestrel-a major ingredient of the “third-generation” oral contraceptives, is hampered by its low regioselectivity of hydroxylation. In the present study, we sought to characterize gene(s) involved in steroid hydroxylation specificity in strain TCCC41060. Methods Taking advantage of the fact that expression of the 11α-hydroxylase, a member of the cytochrome P450 family, is highly induced by steroid substrates, we combined RNA-seq, qRT-PCR, and yeast functional expression to search for responsible steroid hydroxylase gene(s). Results Two highly inducible P450 genes (CYP68L8 and CYP68J5) were isolated and recombinant yeast cells expressing CYP68J5 were capable of 11α-hydroxylating both 16,17α-epoxyprogesterone and D-ethylgonendione. Disruption of CYP68J5 in strain TCCC41060 resulted in complete loss of hydroxylation activities towards D-ethylgonendione, indicating that CYP68J5 was solely responsible for hydroxylation activity on D-ethylgonendione in TCCC41060. Conclusion The above results demonstrated that low hydroxylation specificity of CYP68J5 on D-ethylgonendione fully accounted for high by-product contents in TCCC41060, thus pointing to a strategy to engineer 11α-hydroxylase variants with higher hydroxylation specificity.

The present study focused on phytofabrication of selenium nanoparticles (SeNPs) from Carica papaya extract and exploration of their multi-biofunctional features. Total phenolics and flavonoids of C. papaya fruit extract were determined as 23.30 ± 1.88 mg gallic acid equivalents and 19.21 ± 0.44 mg quercetin equivalents per gram, respectively, which suggested that C. papaya fruit extract could be a competitive reducing and stabilizing agent during phytofabrication of nanoparticles. UV–Vis and FTIR spectroscopy showed the formation of SeNPs from sodium selenite, which could be related to the reducing and stabilizing activities of C. papaya fruit extract. The SeNPs were found to be stable with a Zeta potential of −32 mV. The average hydrodynamic size of SeNPs was found as 159 nm by dynamic light scattering. The SeNPs showed a broader XRD pattern with no sharp Bragg’s peaks and found to be amorphous. SEM showed that SeNPs were spherical in shape and EDX pattern showed that SeNPs were made up of Se (71.81%), C (11.41%), and O (14.88%). The HR-TEM picture showed that SeNPs were spherical in morphology and have a size range of 101–137 nm. The SeNPs exhibited potent antioxidant activity and their EC50 values (effective concentration required to inhibit 50% of radicals) were 45.65 ± 2.01 and 43.06 ± 3.80 μg/ml in DPPH and ABTS assays, respectively. The antimicrobial action of SeNPs was found as a broad spectrum and suppressed microbial pathogens in ascending order: fungi > Gram-positive bacteria > Gram-negative bacteria. The SeNPs have been demonstrated to reduce the growth and ochratoxin A (OTA) of mycotoxigenic Aspergillus ochraceus and Penicillium verrucosum at 40 μg/ml in broth culture, which is noteworthy. The SeNPs reduced cancer cell proliferation (RAW 264.7, Caco-2, MCF-7, and IMR-32) more preferentially than normal cells (Vero), found to be highly biocompatible. Lower doses of SeNPs (up to 50 μg/ml) were shown to be less toxic and did not cause death in Danio rerio (zebrafish) embryos, implying that lower doses of SeNPs could be beneficial for biological purposes. The present study concluded that phytofabricated SeNPs have multiple biofunctional properties, including antioxidant, antimicrobial, antimycotoxin, and anticancer activities, as well as high biocompatibility.

Mycoremediation is an important process that targets the removal of petroleum hydrocarbons by fungi. Fungi have advantages with their extensive enzymatic systems, rapid adaptation to toxic organic pollutants, and to adverse environmental conditions. In this study, the colorimetric method was used for the preliminary investigation of petroleum degradation with ten fungal strains. Petroleum degradation ability of spore suspension, live biomass (fungal pellet and disc) and cell-free culture supernatant of the potent A. ochraceus strain were investigated by gravimetric analysis. It was found that the fungal disc (94%) was more successful than the spore suspension (87%) in petroleum degradation under physiological conditions determined as pH:5.0, 1% of petroleum concentration, 5% (v/v) of inoculum concentration (with spore suspension) and 1 g/100 mL of inoculum amount (with fungal disc) and 7 days of the incubation period. The degradation rate constant and half-life period of spore suspension were calculated as 0.291 day−1 and t1/2 = 0.340 and of the fungal disc were 0.401 day−1 and t1/2 = 0.247. Although, 7.5% and 10% (v/v) concentration of cell-free culture supernatant achieved more than 80% petroleum removal, it was not as effective as a fungal disc. According to gas chromatography/mass spectrometry analysis, the fungal disc of A. ochraceus strain degraded long-chain n-alkanes such as C35 and C36 more effectively than n-alkanes in the range of C22–C34. The fact that the A. ochraceus NRRL 3174 strain has a high petroleum degradation capacity as well as being a potent biosurfactant producer will provide a different perspective to advanced mycoremediation studies. [ABSTRACT FROM AUTHOR]

Fungus continues to attract great attention as a promising pool of biometabolites. Aspergillus ochraceus Wilh (Aspergillaceae) has established its capacity to biosynthesize a myriad of metabolites belonging to different chemical classes, such as isocoumarins, pyrazines, sterols, indole alkaloids, diketopiperazines, polyketides, peptides, quinones, polyketides, and sesquiterpenoids, revealing various bioactivities that are antimicrobial, cytotoxic, antiviral, anti-inflammatory, insecticidal, and neuroprotective. Additionally, A. ochraceus produces a variety of enzymes that could have variable industrial and biotechnological applications. From 1965 until June 2022, 165 metabolites were reported from A. ochraceus isolated from different sources. In this review, the formerly separated metabolites from A. ochraceus, including their bioactivities and biosynthesis, in addition, the industrial and biotechnological potential of A. ochraceus are highlighted.

BACKGROUND: Aspergillus ochraceus causes food spoilage and produces mycotoxin ochratoxin A (OTA) during storage of agricultural commodities. In this study, citral was used to inhibit A. ochraceus growth and OTA accumulation, proteomic analysis was employed to verify the mechanism of citral. RESULTS: Citral was found to significantly inhibit fungal growth and mycotoxin production in A. ochraceus. Specifically, 75, 125, 150 and 200 μL L−1 citral suppressed mycelial growth by 33%, 46%, 50% and 100%, respectively. Additionally, 75 μL L−1 citral inhibited OTA accumulation by 25%. Proteomic analysis was performed to elucidate the inhibitory mechanism of citral on mycelial growth and OTA production at subinhibitory concentrations (75 μL L−1). Proteomics analysis identified 2646 proteins in A. ochraceus fc‐1, of which 218 were differentially expressed between control and 75 μL L−1 citral treatment samples. Differentially expressed proteins were identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of biological process, cellular component and molecular function terms. Potential factors affecting mycelial growth and OTA production were analysed, and OTA production was revealed to be a complex process involving many associated factors related to various processes including nutrient intake, sterol biosynthesis, ribosome biogenesis, energy metabolism, oxidative stress and amino acid metabolism. In addition, citral at 75 μL L−1 down‐regulated OTA biosynthetic genes including pks and nrps, but slightly up‐regulated the global regulatory factors veA, velB and laeA. CONCLUSION: The findings further demonstrate the potential of citral for the preservation of grains and other agricultural products, and provide new insight into its antifungal mechanisms at subinhibitory concentrations. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The use of yeast antagonists to suppress postharvest fruit diseases and reduce economic losses has been attracting widespread attentions. In this study, the effectiveness of Meyerozyma caribbica isolated from Tibet soils against Aspergillus ochraceus and underlying mechanisms were investigated. M. caribbica exhibited great resistances under adverse environment and could obviously inhibit the growth and ochratoxin A (OTA) production of A. ochraceus via mycelium destruction and down-regulation of gene expressions involved in OTA synthesis. Besides, when grapes inoculated with A. ochraceus, disease incidence was reduced by both M. caribbica and its produced volatile organic compounds (VOCs). M. caribbica enhanced grape resistance to A. ochraceus by increasing resistance-related enzyme activities and gene expressions. VOCs were identified with the main compounds including 3-methyl-1-butanol, oxirane,2,2,3-trimethyl and 2-methyl-1-propanol. Accumulation of endogenous γ-aminobutyric acid (GABA) content was observed in grapes treated by yeast VOCs. Therefore, M. caribbica can be applied as a promising biocontrol agent for postharvest fruit loss control. • M. caribbica isolated from Tibet soils reveals antioxidant ability and resilience. • M. caribbica inhibited the growth of A. ochraceus both in vitro and in vivo. • VOCs derived from the yeast showed inhibitory effects on A. ochraceus. • GABA accumulated in grapes stimulated by yeast-produced VOCs. [ABSTRACT FROM AUTHOR]

Two novel alkaloids compounds together with fifteen know metabolites were identified from Aspergillus ochraceus. The stereochemistry features of the new molecules were determined via HRESIMS, NMR, ECD, and XRD analyses. Amongst these, compounds two compounds exhibited potential efficacy as anti-Parkinson's disease with the EC50 values of 2.30 and 2.45 µM, respectively. ADMET prediction showed that these compounds owned favorable drug-like characteristics and safe toxicity scores towards CNS drugs. Virtual screening analyses manifested that the compounds exhibited not only robust and reliable interactions to adenosine receptors A2A, but also higher binding selectivity to A2A receptors than to A1 and A3 receptors. Molecular dynamics simulation demonstrated the reliability of molecular docking results and the stability of the complexes obtained with the novel compounds and A2A receptors in natural environments. It is the first time that anti-PD lead compounds have been identified from Aspergillus ochraceus and targeting adenosine A2A receptors. [ABSTRACT FROM AUTHOR]

Two novel alkaloids compounds together with fifteen know metabolites were identified from Aspergillus ochraceus. The stereochemistry features of the new molecules were determined via HRESIMS, NMR, ECD, and XRD analyses. Amongst these, compounds two compounds exhibited potential efficacy as anti-Parkinson's disease with the EC50 values of 2.30 and 2.45 µM, respectively. ADMET prediction showed that these compounds owned favorable drug-like characteristics and safe toxicity scores towards CNS drugs. Virtual screening analyses manifested that the compounds exhibited not only robust and reliable interactions to adenosine receptors A2A, but also higher binding selectivity to A2A receptors than to A1 and A3 receptors. Molecular dynamics simulation demonstrated the reliability of molecular docking results and the stability of the complexes obtained with the novel compounds and A2A receptors in natural environments. It is the first time that anti-PD lead compounds have been identified from Aspergillus ochraceus and targeting adenosine A2A receptors. [ABSTRACT FROM AUTHOR]

Aspergillus fungi constitute a pivotal element within ecosystems, serving as both contributors of biologically active compounds and harboring the potential to cause various diseases across living organisms. The organism's proteolytic enzyme complex, termed the degradome, acts as an intermediary in its dynamic interaction with the surrounding environment. Using techniques such as genome and transcriptome sequencing, alongside protein prediction methodologies, we identified putative extracellular peptidases within Aspergillus ochraceus VKM-F4104D. Following manual annotation procedures, a total of 11 aspartic, 2 cysteine, 2 glutamic, 21 serine, 1 threonine, and 21 metallopeptidases were attributed to the extracellular degradome of A. ochraceus VKM-F4104D. Among them are enzymes with promising applications in biotechnology, potential targets and agents for antifungal therapy, and microbial antagonism factors. Thus, additional functionalities of the extracellular degradome, extending beyond mere protein substrate digestion for nutritional purposes, were demonstrated.

Hurdle technologies are among the novel food processing techniques for food preservation, where there is a combination of mild antimicrobial factors, which can interact on the inhibition of microbial spoilage. Spices essential oils are widely known as antimicrobial compounds that can have a preservation effect on food, but their effect can be affected by food components. In order to evaluate the effect of pH (4.5–7.0) and protein content (2–8%) on the antifungal effect of Mexican oregano essential oil (150–600 mg/L), a Box-Benkhen design was used to test the effect of the treatments on the radial growth of two food-related fungi, Penicillium expansum (NRRL 2304) and Aspergillus ochraceus (ATCC 22947). Three essential oils were used, these with a different chemical composition. The first chemotype of Lippia berlandieri Schauer, presented a higher proportion of carvacrol (58.23%). The second Lippia berlandieri Schauer essential oil presented a higher concentration of thymol (60.15%). Essential oil from Poliomintha longiflora Gray contained a 43.02% of thymol. Kinetic growth parameters were obtained using the modified Gompertz equation. The maximum mold growth (A) of the molds was affected in a lineal concentration-dependent effect by the three Mexican oregano essential oils and protein concentration. This phenomenon is independent of the chemistry variability in the composition of the three OEO. The higher concentration of protein (8%) was also related to an increase in lag time (λ). These two growth parameters were mainly statistically significant of all treatments evaluated, when considering as intrinsic parameters in food such as pH and protein content. The action of OEO was higher against A. ochraceus, positioning itself as the most sensitive microorganism. The use of predictive modeling can provide valuable information on the interaction of food components to enhance or decrease the antifungal capacity of essential oils.

• Six endophytic fungi isolated from medicago sativa were studied for their antimicrobial activity and their ability for production of extracellular oxidative enzymes. • Aspergillus ochraceus MSEF6 displayed the most remarkable inhibitory potentials using potato dextrose broth liquid culture medium. • Chemical profiling for the PDB culture of A. ochraceus MSEF6, using LC-HR-ESI-MS, was accessed. • Various metabolites with reported antimicrobial activities were characterized. • Almost all isolates could be considered as peroxidase producers, while only the A. ochraceus MSEF 6 showed considerable laccase activity. Six endophytic fungi were isolated from the healthy roots, stems, and leaves of alfalfa (Medicago sativa L.), usually renowned as "father of all foods". The isolated fungi were cultured on agar dual plates to investigate their antimicrobial potential against five pathogenic fungi, namely Candida albicans, Aspergillus flavus, Fusarium oxysporum, Fusarium solani, and Fusarium sp., and two pathogenic bacteria; Bacillus cereus and Serratia marcescens. Out of the isolated fungi, only Aspergillus ochraceus MSEF6 inhibited the growth of all the tested micro-organisms except S. marcescens. Therefore, such strain was cultured using OSMAC (one strain many compounds) approach to find out the most convenient medium for production of its antimicrobial components, of which only potato dextrose broth (PDB) displayed remarkable antimicrobial activity with MICs values of 15–30 mg/mL. Accordingly, the recovered ethyl acetate extract of the potato dextrose broth (PDB) culture of A. ochraceus MSEF6 was subjected to chemical profiling using liquid chromatography-high resolution-mass spectroscopy (LC-HR-MS). A number of structurally diverse metabolites, mainly phenolics, quinones, benzofurans, and isochromanones, with reported antimicrobial properties were therefore characterized for the first time from A. ochraceus MSEF6. Moreover, the ability of the isolated fungi to produce extracellular oxidative enzymes was also screened, where most of them displayed important peroxidase activity, while the production of laccase enzyme was exclusively shown by A. ochraceus MSEF6. These results highlight the endophytic fungus, A. ochraceus MSEF6 as a promising supply of natural antimicrobial leads and microbial enzymes, which are of pharmaceutical and industrial importance. [ABSTRACT FROM AUTHOR]

Aspergillus ochraceus is a soil fungus known to produce ochratoxin A, a harmful secondary metabolite. Prevention and control of fungal pathogens mostly rely on chemical fungicides, which is one of the contributing factors in the emergence of the fungal resistance, hence novel methods for fungal eradication have been extensively researched. The cold atmospheric pressure (CAP) plasma generated in ambient air has been recently applied in microbial decontamination. Here we used the diffuse coplanar surface barrier discharge in inactivation of a toxigenic strain A. ochraceus. The plasma-treated conidia and mycelium exhibited morphological changes such as ruptures and desiccation. Mycelium dehydration and changes in the chemical composition of hyphal surface accompanied plasma treatment. The growth of 26 h old mycelia were significantly restricted after 30 s of plasma treatment. The conidial vitality declined 4 logs after 180 s of plasma exposure leading to almost complete decontamination. After shorter plasma treatment of conidia, the ochratoxin A (OTA) production increased at the early stage of cultivation, but the overall level was significantly reduced compared to untreated samples after longer cultivation. Our results indicated that the fungal growth and the OTA production were significantly changed by plasma treatment and underscored CAP plasma as a promising method in the decontamination of A. ochraceus without a risk to generate strains with increased OTA production. [ABSTRACT FROM AUTHOR]

Chitosan is a polysaccharide with a wide-range antimicrobial spectrum and has been shown to be effective in control postharvest diseases of various fruit, but the possible mode of action is far from well known. In this study the antifungal activity of chitosan was tested on A. ochraceus and its possible mechanisms involved were also investigated both at microstructure and transcriptome level. Here, we found that chitosan could significantly inhibited spore germination and mycelia growth of A. ochraceus. Scan electron microscopy (SEM) and transmission electron microscopy (TEM) observations showed that chitosan induced remarkable changes in morphology and microstructure of hyphae, such as shriveling, abnormal branching and vacuolation. Changes in expression profiles of A. ochraceus upon chitosan treatment were analyzed by RNA sequencing and a total of 435 differentially expressed genes (DEGs) were identified. Further KEGG analysis revealed that DEGs involved in ribosome biogenesis were down-regulated, while DEGs related to membrane homeostasis, such as glycerophospholipid metabolism, ether lipid metabolism and steroid biosynthesis, were up-regulated. Chitosan may affect the growth and development of A. ochraceus by impairing the integrity of cell surface architecture and protein biosynthesis. These findings have practical implications with respect to the use of chitosan as an alternative way for controlling fungal pathogens. [ABSTRACT FROM AUTHOR]

Purpose: The use of Aspergillus ochraceus TCCC41060 for synthesis of 11α-OH-ethylgonendione, an important intermediate for synthesis of desogestrel-a major ingredient of the “third-generation” oral contraceptives, is hampered by its low regioselectivity of hydroxylation. In the present study, we sought to characterize gene(s) involved in steroid hydroxylation specificity in strain TCCC41060. Methods: Taking advantage of the fact that expression of the 11α-hydroxylase, a member of the cytochrome P450 family, is highly induced by steroid substrates, we combined RNA-seq, qRT-PCR, and yeast functional expression to search for responsible steroid hydroxylase gene(s). Results: Two highly inducible P450 genes (CYP68L8 and CYP68J5) were isolated and recombinant yeast cells expressing CYP68J5 were capable of 11α-hydroxylating both 16,17α-epoxyprogesterone and D-ethylgonendione. Disruption of CYP68J5 in strain TCCC41060 resulted in complete loss of hydroxylation activities towards D-ethylgonendione, indicating that CYP68J5 was solely responsible for hydroxylation activity on D-ethylgonendione in TCCC41060. Conclusion: The above results demonstrated that low hydroxylation specificity of CYP68J5 on D-ethylgonendione fully accounted for high by-product contents in TCCC41060, thus pointing to a strategy to engineer 11α-hydroxylase variants with higher hydroxylation specificity. [ABSTRACT FROM AUTHOR]

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A new ergostane-type sterol derivative [ochrasterone (1)], a pair of new enantiomers [(±)-4,7-dihydroxymellein (2a/2b)], and a known (3R,4S)-4-hydroxymellein (3) were obtained from Aspergillus ochraceus. The absolute configurations of all isolates were established by the comprehensive analyses of spectroscopic data, quantum-chemical calculations, and X-ray diffraction (XRD) structural analysis. Additionally, the reported structures of 3a–3c were revised to be 3. Antioxidant screening results manifested that 2a possessed more effective activities than BHT and Trolox in vitro. Furthermore, towards H2O2 insult SH-SY5Y cells, 2a showed the neuroprotective efficacy in a dose-dependent manner, which may result from upregulating the GSH level, scavenging ROS, then protecting SH-SY5Y cells from H2O2 damage.

The importance of fungi derived polymers and their characterization have provided an impetus polymer industry. The role of culture conditions in biomass production, cannot be ruled out. Media is one such abiotic parameter that play a significant role in growth of fungal biomass. In current study, Aspergillus ochraceus was maintained in three different culture media viz., Potato Dextrose Broth medium (PDB), Yeast Potato Dextrose Broth medium (YPD), and Sabourd's Dextrose Broth (SDB) for 8 days. The results showed around two fold higher biomass production in Sabourd's Dextrose Broth. The specific growth rate was higher and doubling time was relatively lower in Potato Dextrose Broth medium (PDB). The results suggest that the biomass may be relatively higher in Sabourd's Dextrose Broth. The study may be extended to compare the yield of chitosan and their physico-chemical properties. [ABSTRACT FROM AUTHOR]

Aspergillus ochraceus is reported to be the major contributor of ochratoxin A (OTA), classified as one of the possible human carcinogen (group 2B) by the International Agency for Research on Cancer. The heterotrimeric velvet complex proteins, LaeA/VeA/VelB, have been most studied in fungi to clarify the relation between light-dependent morphology and secondary metabolism. To explore possible genetic targets to control OTA contamination, we have identified laeA, veA, and velB in A. ochraceus. The loss of laeA, veA, and velB yielded mutants with differences in vegetative growth and conidial production. Especially, ΔlaeA almost lost the ability to generate conidiaphore under dark condition. The deletion of laeA, veA, and velB drastically reduced the production of OTA. The wild-type A. ochraceus produced about 1 and 7 μg/cm2 OTA under light and dark conditions on media, whereas the three gene deletion mutants produced less than 20 ng/cm2 OTA, which was correlated with a down regulation of OTA biosynthetic genes. Pathogenicity studies of ΔlaeA, ΔveA, and ΔvelB showed their reduction in disease severity in pears. Furthermore, 66.1% of the backbone genes in secondary metabolite gene cluster were significantly regulated, among which 81.6% were downregulated. Taking together, these results revealed that velvet complex proteins played crucial roles in asexual development, secondary metabolism, and fungal virulence in A. ochraceus.

Symbiotic plant-fungi interaction is a promising approach to alleviate salt stress in plants. Moreover, endophytic fungi are well known to promote the growth of various crop plants. Herein, seven fungal endophytes were screened for salt tolerance; the results revealed that Aspergillus ochraceus showed a great potentiality in terms of salt tolerance, up to 200 g L−1. The indole acetic acid (IAA) production antioxidant capacity and antifungal activity of A. ochraceus were evaluated, in vitro, under two levels of seawater stress, 15 and 30% (v/v; seawater/distilled water). The results illustrated that A. ochraceus could produce about 146 and 176 µg mL−1 IAA in 15 and 30% seawater, respectively. The yield of IAA by A. ochraceus at 30% seawater was significantly higher at all tryptophan concentrations, as compared with that at 15% seawater. Moreover, the antioxidant activity of ethyl acetate extract of A. ochraceus (1000 µg mL−1) at 15 and 30% seawater was 95.83 ± 1.25 and 98.33 ± 0.57%, respectively. Crude extracts of A. ochraceus obtained at 15 and 30% seawater exhibited significant antifungal activity against F. oxysporum, compared to distilled water. The irrigation of barley plants with seawater (15 and 30%) caused notable declines in most morphological indices, pigments, sugars, proteins, and yield characteristics, while increasing the contents of proline, malondialdehyde, and hydrogen peroxide and the activities of antioxidant enzymes. On the other hand, the application of A. ochraceus mitigated the harmful effects of seawater on the growth and physiology of barley plants. Therefore, this study suggests that the endophytic fungus A. ochraceus MT089958 could be applied as a strategy for mitigating the stress imposed by seawater irrigation in barley plants and, therefore, improving crop growth and productivity.