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Jia X, Song J, Wu Y, Feng S, Sun Z, Hu Y, Yu M, Han R, Zeng B. Strategies for the Enhancement of Secondary Metabolite Production via Biosynthesis Gene Cluster Regulation in Aspergillus oryzae. J Fungi (Basel) 2024; 10:312. [PMID: 38786667 PMCID: PMC11121810 DOI: 10.3390/jof10050312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/17/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
The filamentous fungus Aspergillus oryzae (A. oryzae) has been extensively used for the biosynthesis of numerous secondary metabolites with significant applications in agriculture and food and medical industries, among others. However, the identification and functional prediction of metabolites through genome mining in A. oryzae are hindered by the complex regulatory mechanisms of secondary metabolite biosynthesis and the inactivity of most of the biosynthetic gene clusters involved. The global regulatory factors, pathway-specific regulatory factors, epigenetics, and environmental signals significantly impact the production of secondary metabolites, indicating that appropriate gene-level modulations are expected to promote the biosynthesis of secondary metabolites in A. oryzae. This review mainly focuses on illuminating the molecular regulatory mechanisms for the activation of potentially unexpressed pathways, possibly revealing the effects of transcriptional, epigenetic, and environmental signal regulation. By gaining a comprehensive understanding of the regulatory mechanisms of secondary metabolite biosynthesis, strategies can be developed to enhance the production and utilization of these metabolites, and potential functions can be fully exploited.
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Affiliation(s)
- Xiao Jia
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
- College of Materials and Energy, Jiangxi Science and Technology Normal University, Nanchang 330013, China
| | - Jiayi Song
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
- College of Life and Health Sciences, Northeastern University, No. 3-11, Wenhua Road, Shenyang 110819, China
| | - Yijian Wu
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
| | - Sai Feng
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
| | - Zeao Sun
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
| | - Yan Hu
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
| | - Mengxue Yu
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
| | - Rui Han
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
| | - Bin Zeng
- College of Pharmacy, Shenzhen Technology University, Shenzhen 518118, China; (X.J.); (J.S.); (Y.W.); (S.F.); (Z.S.); (Y.H.); (M.Y.); (R.H.)
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Jaćević V, Dumanović J, Alomar SY, Resanović R, Milovanović Z, Nepovimova E, Wu Q, Franca TCC, Wu W, Kuča K. Research update on aflatoxins toxicity, metabolism, distribution, and detection: A concise overview. Toxicology 2023; 492:153549. [PMID: 37209941 DOI: 10.1016/j.tox.2023.153549] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/07/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
Serious health risks associated with the consumption of food products contaminated with aflatoxins (AFs) are worldwide recognized and depend predominantly on consumed AF concentration by diet. A low concentration of aflatoxins in cereals and related food commodities is unavoidable, especially in subtropic and tropic regions. Accordingly, risk assessment guidelines established by regulatory bodies in different countries help in the prevention of aflatoxin intoxication and the protection of public health. By assessing the maximal levels of aflatoxins in food products which are a potential risk to human health, it's possible to establish appropriate risk management strategies. Regarding, a few factors are crucial for making a rational risk management decision, such as toxicological profile, adequate information concerning the exposure duration, availability of routine and some novel analytical techniques, socioeconomic factors, food intake patterns, and maximal allowed levels of each aflatoxin in different food products which may be varied between countries.
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Affiliation(s)
- Vesna Jaćević
- Department for Experimental Pharmacology and Toxicology, National Poison Control Centre, Military Medical Academy, Crnotravska 17, 11000 Belgrade, Serbia; Medical Faculty of the Military Medical Academy, University of Defence, Crnotravska 17, 11000 Belgrade, Serbia; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic.
| | - Jelena Dumanović
- Medical Faculty of the Military Medical Academy, University of Defence, Crnotravska 17, 11000 Belgrade, Serbia; Department of Analytical Chemistry, Faculty of Chemistry, University of Belgrade, 11158 Belgrade, Serbia
| | - Suliman Y Alomar
- King Saud University, College of Science, Zoology Department, Riyadh, 11451, Saudi Arabia
| | - Radmila Resanović
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar Oslobođenja 18, 11000 Belgrade, Serbia
| | - Zoran Milovanović
- Special Police Unit, Ministry of Interior, Trebevićka 12/A, 11 030 Belgrade, Serbia
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Qinghua Wu
- College of Life Science, Yangtze University, 1 Nanhuan Road, 434023 Jingzhou, Hubei, China; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Tanos Celmar Costa Franca
- Laboratory of Molecular Modeling Applied to the Chemical and Biological Defense, Military Institute of Engineering, Praça General Tibúrcio 80, Rio de Janeiro, RJ 22290-270, Brazil; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Wenda Wu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Kamil Kuča
- Biomedical Research Center, University Hospital Hradec Kralove, 50005, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
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Zhang L, Kang L, Xu Y. Phenotypic, Genomic, and Transcriptomic Comparison of Industrial Aspergillus oryzae Used in Chinese and Japanese Soy Sauce: Analysis of Key Proteolytic Enzymes Produced by Koji Molds. Microbiol Spectr 2023; 11:e0083622. [PMID: 36744888 PMCID: PMC10100866 DOI: 10.1128/spectrum.00836-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 01/11/2023] [Indexed: 02/07/2023] Open
Abstract
Aspergillus oryzae, which generates numerous enzymes for the breakdown of raw materials, is an essential koji mold in soy sauce production. For better soy sauce productivity and flavor quality, China and Japan have developed their own industrial A. oryzae strains at distinct evolutionary branches for use in soy sauce production for decades. However, systematic comparison between the two national industrial strains has been poorly conducted, and thus we have not been able to generate adequate knowledge, especially regarding what are the key hydrolytic enzymes produced by A. oryzae during koji production. This study sequenced and assembled three high-quality genome sequences of industrial A. oryzae originating from China and Japan. Based on the genome sequences, a phylogenetic tree analysis was performed and revealed the evolutional distances between the two national industrial koji molds. Meanwhile, a comparative phenotypic analysis revealed that the two national industrial strains differed in growth and catalytic characteristics, particularly in proteolytic enzyme activities. To investigate the molecular mechanism underlying the phenotypic difference, we conducted systematic comparative genome and transcriptome investigations. We found minor differences in the quantity and diversity of proteolytic enzyme genes between Chinese and Japanese koji molds, while the protease secretion ratio and transcriptional level were dissimilar. We identified 58 potential important enzymes associated with high protein breakdown efficiency during industrial koji fermentation by combining comparative phenotypic and transcriptome data. More research is required to confirm the function of these putative key hydrolytic enzymes. IMPORTANCE Aspergillus oryzae is widely used as an industrial koji mold for soy sauce brewing due to its powerful raw material decomposition capability. Although various proteases in A. oryzae have been identified, it remains a challenge to find essential enzymes involved in soy sauce production. Generally, the industrial A. oryzae used in soy sauce brewing has excellent proteolytic activity. Based on this, we analyzed key proteolytic enzymes according to a comparison of the genome and transcriptome between three industrial strains. This study found little difference in gene numbers and mutations of proteolytic enzymes between three industrial A. oryzae strains. However, variations in protease secretion ratio and transcriptome were discovered between industrial strains. Based on that, we generated 58 candidate key proteolytic enzymes. This work comprehensively analyzed three industrial koji molds, revealing genome development under separate artificial domestication and helping in the study of key proteolytic enzymes during soy sauce production.
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Affiliation(s)
- Lijie Zhang
- Laboratory of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Le Kang
- Laboratory of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yan Xu
- Laboratory of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
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Wokorach G, Landschoot S, Lakot A, Karyeija SA, Audenaert K, Echodu R, Haesaert G. Characterization of Ugandan Endemic Aspergillus Species and Identification of Non-Aflatoxigenic Isolates for Potential Biocontrol of Aflatoxins. Toxins (Basel) 2022; 14:304. [PMID: 35622551 PMCID: PMC9143334 DOI: 10.3390/toxins14050304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/19/2022] [Accepted: 04/24/2022] [Indexed: 12/10/2022] Open
Abstract
Acute stunting in children, liver cancer, and death often occur due to human exposure to aflatoxins in food. The severity of aflatoxin contamination depends on the type of Aspergillus fungus infecting the crops. In this study, Aspergillus species were isolated from households’ staple foods and were characterized for different aflatoxin chemotypes. The non-aflatoxigenic chemotypes were evaluated for their ability to reduce aflatoxin levels produced by aflatoxigenic A. flavus strains on maize grains. Aspergillus flavus (63%), A. tamarii (14%), and A. niger (23%) were the main species present. The A. flavus species included isolates that predominantly produced aflatoxins B1 and B2, with most isolates producing a high amount (>20 ug/µL) of aflatoxin B1 (AFB1), and a marginal proportion of them also producing G aflatoxins with a higher level of aflatoxin G1 (AFG1) than AFB1. Some non-aflatoxigenic A. tamarii demonstrated a strong ability to reduce the level of AFB1 by more than 95% when co-inoculated with aflatoxigenic A. flavus. Therefore, field evaluation of both non-aflatoxigenic A. flavus and A. tamarii would be an important step toward developing biocontrol agents for mitigating field contamination of crops with aflatoxins in Uganda.
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Affiliation(s)
- Godfrey Wokorach
- Department of Plants and Crops, Campus Schoonmeersen Building C, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium; (G.W.); (S.L.); (K.A.)
- Multifunctional Research Laboratories, Gulu University, Gulu P.O. Box 166, Uganda; (A.L.); (S.A.K.); (R.E.)
| | - Sofie Landschoot
- Department of Plants and Crops, Campus Schoonmeersen Building C, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium; (G.W.); (S.L.); (K.A.)
| | - Amerida Lakot
- Multifunctional Research Laboratories, Gulu University, Gulu P.O. Box 166, Uganda; (A.L.); (S.A.K.); (R.E.)
| | - Sidney Arihona Karyeija
- Multifunctional Research Laboratories, Gulu University, Gulu P.O. Box 166, Uganda; (A.L.); (S.A.K.); (R.E.)
| | - Kris Audenaert
- Department of Plants and Crops, Campus Schoonmeersen Building C, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium; (G.W.); (S.L.); (K.A.)
| | - Richard Echodu
- Multifunctional Research Laboratories, Gulu University, Gulu P.O. Box 166, Uganda; (A.L.); (S.A.K.); (R.E.)
- Department of Biology, Faculty of Science, Gulu University, Gulu P.O. Box 166, Uganda
| | - Geert Haesaert
- Department of Plants and Crops, Campus Schoonmeersen Building C, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium; (G.W.); (S.L.); (K.A.)
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Development of an on-spot and rapid recombinase polymerase amplification assay for Aspergillus flavus detection in grains. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.107957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Mahato DK, Lee KE, Kamle M, Devi S, Dewangan KN, Kumar P, Kang SG. Aflatoxins in Food and Feed: An Overview on Prevalence, Detection and Control Strategies. Front Microbiol 2019; 10:2266. [PMID: 31636616 PMCID: PMC6787635 DOI: 10.3389/fmicb.2019.02266] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022] Open
Abstract
Aflatoxins produced by the Aspergillus species are highly toxic, carcinogenic, and cause severe contamination to food sources, leading to serious health consequences. Contaminations by aflatoxins have been reported in food and feed, such as groundnuts, millet, sesame seeds, maize, wheat, rice, fig, spices and cocoa due to fungal infection during pre- and post-harvest conditions. Besides these food products, commercial products like peanut butter, cooking oil and cosmetics have also been reported to be contaminated by aflatoxins. Even a low concentration of aflatoxins is hazardous for human and livestock. The identification and quantification of aflatoxins in food and feed is a major challenge to guarantee food safety. Therefore, developing feasible, sensitive and robust analytical methods is paramount for the identification and quantification of aflatoxins present in low concentrations in food and feed. There are various chromatographic and sensor-based methods used for the detection of aflatoxins. The current review provides insight into the sources of contamination, occurrence, detection techniques, and masked mycotoxin, in addition to management strategies of aflatoxins to ensure food safety and security.
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Affiliation(s)
- Dipendra K. Mahato
- School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC, Australia
| | - Kyung Eun Lee
- Molecular Genetics Laboratory, Department of Biotechnology, Yeungnam University, Gyeongsan, South Korea
| | - Madhu Kamle
- Department of Forestry, North Eastern Regional Institute of Science and Technology, Nirjuli, India
| | | | - Krishna N. Dewangan
- Department of Agricultural Engineering, North Eastern Regional Institute of Science and Technology, Nirjuli, India
| | - Pradeep Kumar
- Department of Forestry, North Eastern Regional Institute of Science and Technology, Nirjuli, India
| | - Sang G. Kang
- Molecular Genetics Laboratory, Department of Biotechnology, Yeungnam University, Gyeongsan, South Korea
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Frisvad J, Hubka V, Ezekiel C, Hong SB, Nováková A, Chen A, Arzanlou M, Larsen T, Sklenář F, Mahakarnchanakul W, Samson R, Houbraken J. Taxonomy of Aspergillus section Flavi and their production of aflatoxins, ochratoxins and other mycotoxins. Stud Mycol 2019; 93:1-63. [PMID: 30108412 PMCID: PMC6080641 DOI: 10.1016/j.simyco.2018.06.001] [Citation(s) in RCA: 270] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aflatoxins and ochratoxins are among the most important mycotoxins of all and producers of both types of mycotoxins are present in Aspergillus section Flavi, albeit never in the same species. Some of the most efficient producers of aflatoxins and ochratoxins have not been described yet. Using a polyphasic approach combining phenotype, physiology, sequence and extrolite data, we describe here eight new species in section Flavi. Phylogenetically, section Flavi is split in eight clades and the section currently contains 33 species. Two species only produce aflatoxin B1 and B2 (A. pseudotamarii and A. togoensis), and 14 species are able to produce aflatoxin B1, B2, G1 and G2: three newly described species A. aflatoxiformans, A. austwickii and A. cerealis in addition to A. arachidicola, A. minisclerotigenes, A. mottae, A. luteovirescens (formerly A. bombycis), A. nomius, A. novoparasiticus, A. parasiticus, A. pseudocaelatus, A. pseudonomius, A. sergii and A. transmontanensis. It is generally accepted that A. flavus is unable to produce type G aflatoxins, but here we report on Korean strains that also produce aflatoxin G1 and G2. One strain of A. bertholletius can produce the immediate aflatoxin precursor 3-O-methylsterigmatocystin, and one strain of Aspergillus sojae and two strains of Aspergillus alliaceus produced versicolorins. Strains of the domesticated forms of A. flavus and A. parasiticus, A. oryzae and A. sojae, respectively, lost their ability to produce aflatoxins, and from the remaining phylogenetically closely related species (belonging to the A. flavus-, A. tamarii-, A. bertholletius- and A. nomius-clades), only A. caelatus, A. subflavus and A. tamarii are unable to produce aflatoxins. With exception of A. togoensis in the A. coremiiformis-clade, all species in the phylogenetically more distant clades (A. alliaceus-, A. coremiiformis-, A. leporis- and A. avenaceus-clade) are unable to produce aflatoxins. Three out of the four species in the A. alliaceus-clade can produce the mycotoxin ochratoxin A: A. alliaceus s. str. and two new species described here as A. neoalliaceus and A. vandermerwei. Eight species produced the mycotoxin tenuazonic acid: A. bertholletius, A. caelatus, A. luteovirescens, A. nomius, A. pseudocaelatus, A. pseudonomius, A. pseudotamarii and A. tamarii while the related mycotoxin cyclopiazonic acid was produced by 13 species: A. aflatoxiformans, A. austwickii, A. bertholletius, A. cerealis, A. flavus, A. minisclerotigenes, A. mottae, A. oryzae, A. pipericola, A. pseudocaelatus, A. pseudotamarii, A. sergii and A. tamarii. Furthermore, A. hancockii produced speradine A, a compound related to cyclopiazonic acid. Selected A. aflatoxiformans, A. austwickii, A. cerealis, A. flavus, A. minisclerotigenes, A. pipericola and A. sergii strains produced small sclerotia containing the mycotoxin aflatrem. Kojic acid has been found in all species in section Flavi, except A. avenaceus and A. coremiiformis. Only six species in the section did not produce any known mycotoxins: A. aspearensis, A. coremiiformis, A. lanosus, A. leporis, A. sojae and A. subflavus. An overview of other small molecule extrolites produced in Aspergillus section Flavi is given.
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Affiliation(s)
- J.C. Frisvad
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - V. Hubka
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague 2, Czech Republic
- Institute of Microbiology of the CAS, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - C.N. Ezekiel
- Department of Microbiology, Babcock University, Ilishan Rémo, Nigeria
| | - S.-B. Hong
- Korean Agricultural Culture Collection, National Academy of Agricultural Science, RDA, Suwon, South Korea
| | - A. Nováková
- Institute of Microbiology of the CAS, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - A.J. Chen
- Institute of Medical Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, PR China
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - M. Arzanlou
- Department of Plant Protection, University of Tabriz, Tabriz, Iran
| | - T.O. Larsen
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - F. Sklenář
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague 2, Czech Republic
- Institute of Microbiology of the CAS, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - W. Mahakarnchanakul
- Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand
| | - R.A. Samson
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
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Yin G, Hua SST, Pennerman KK, Yu J, Bu L, Sayre RT, Bennett JW. Genome sequence and comparative analyses of atoxigenic Aspergillus flavus WRRL 1519. Mycologia 2018; 110:482-493. [PMID: 29969379 DOI: 10.1080/00275514.2018.1468201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aflatoxins are toxic secondary metabolites produced by Aspergillus flavus and a few other closely related species of Aspergillus. These highly toxigenic and carcinogenic mycotoxins contaminate global food and feed supplies, posing widespread health risks to humans and domestic animals. Field application of nonaflatoxigenic strains of A. flavus to compete against aflatoxigenic strains has emerged as one of the best management practices for reducing aflatoxins contamination, yielding successful commercial products for corn, cotton seed, and peanuts. In this study, we sequenced the genome and transcriptome of atoxigenic (does not produce aflatoxin or cyclopiazonic acid) A. flavus strain WRRL 1519 isolated from a tree nut orchard to define the genetic characteristics of the strain in relation to aflatoxigenic and other nonaflatoxigenic A. flavus strains. WRRL 1519 strain was similar to other strains in size (38.0 Mb), GC content (47.2%), number of predicted secondary metabolite gene clusters (46), and number of putative proteins (12 121). About 87.4% of the predicted proteome had high shared identity with protein sequences derived from other A. flavus genomes. However, the atoxigenic A. flavus strain WRRL 1519 had deletions, or low shared identity, for many genes in the clusters required for aflatoxins and cyclopiazonic acid (CPA) synthesis. Over half of the aflatoxin synthesis gene cluster was missing, and none of the components of the CPA gene cluster were identified with high sequence similarity. Importantly, the strain appeared to maintain functional sequences of several genes thought to be required for high infectivity. Since the ability to grow on target crop is an important attribute for a successful biocontrol agent, these results indicate that the nonaflatoxigenic A. flavus strain WRRL 1519 would be a good candidate as a biocontrol agent for reducing aflatoxin and CPA accumulation in high-value nut crops.
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Affiliation(s)
- Guohua Yin
- a Department of Plant Biology, Rutgers , The State University of New Jersey , New Brunswick , New Jersey 08901.,b New Mexico Consortium and Pebble Labs , Los Alamos , New Mexico 87544
| | - Sui Sheng T Hua
- c Foodborne Toxin Detection and Prevention Research, Western Regional Research Center, Agricultural Research Service , US Department of Agriculture , Albany , California 94710
| | - Kayla K Pennerman
- a Department of Plant Biology, Rutgers , The State University of New Jersey , New Brunswick , New Jersey 08901
| | - Jiujiang Yu
- d Food Quality Laboratory, Agricultural Research Service , US Department of Agriculture, Beltsville Agricultural Research Center , Beltsville , Maryland 20705
| | - Lijing Bu
- e Center for Evolutionary & Theoretical Immunology, Department of Biology , University of New Mexico , Albuquerque , New Mexico 87131
| | - Richard T Sayre
- b New Mexico Consortium and Pebble Labs , Los Alamos , New Mexico 87544
| | - Joan W Bennett
- a Department of Plant Biology, Rutgers , The State University of New Jersey , New Brunswick , New Jersey 08901
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LAMP-based group specific detection of aflatoxin producers within Aspergillus section Flavi in food raw materials, spices, and dried fruit using neutral red for visible-light signal detection. Int J Food Microbiol 2017; 266:241-250. [PMID: 29272724 DOI: 10.1016/j.ijfoodmicro.2017.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 01/10/2023]
Abstract
Aflatoxins can be produced by 21 species within sections Flavi (16 species), Ochraceorosei (2), and Nidulantes (3) of the fungal genus Aspergillus. They pose risks to human and animal health due to high toxicity and carcinogenicity. Detecting aflatoxin producers can help to assess toxicological risks associated with contaminated commodities. Species specific molecular assays (PCR and LAMP) are available for detection of major producers, but fail to detect species of minor importance. To enable rapid and sensitive detection of several aflatoxin producing species in a single analysis, a nor1 gene-specific LAMP assay was developed. Specificity testing showed that among 128 fungal species from 28 genera, 15 aflatoxigenic species in section Flavi were detected, including synonyms of A. flavus and A. parasiticus. No cross reactions were found with other tested species. The detection limit of the assay was 9.03pg of A. parasiticus genomic DNA per reaction. Visual detection of positive LAMP reactions under daylight conditions was facilitated using neutral red to allow unambiguous distinction between positive and negative assay results. Application of the assay to the detection of A. parasiticus conidia revealed a detection limit of 211 conidia per reaction after minimal sample preparation. The usefulness of the assay was demonstrated in the analysis of aflatoxinogenic species in samples of rice, nuts, raisins, dried figs, as well as powdered spices. Comparison of LAMP results with presence/absence of aflatoxins and aflatoxin producing fungi in 50 rice samples showed good correlation between these parameters. Our study suggests that the developed LAMP assay is a rapid, sensitive and user-friendly tool for surveillance and quality control in our food industry.
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Li Z, Ji GE. Ginseng fermented by mycotoxin non-producing Aspergillus niger: ginsenoside analysis and anti-proliferative effects. Food Sci Biotechnol 2017; 26:987-991. [PMID: 30263628 DOI: 10.1007/s10068-017-0117-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/31/2017] [Accepted: 03/23/2017] [Indexed: 01/01/2023] Open
Abstract
Korean ginseng was fermented using Aspergillus niger (A. niger) FMB S494 and mycotoxins such as ochratoxin and fumonisin were not detected in the fermented ginseng. Protopanaxadiol-type ginsenosides such as glycosylated forms of Rb1, Rb2, Rc, and Rd decreased to 0 while compound K (cK) increased from 0 to 9 × 104 ppm in the extract of fermented ginseng. Protopanaxtriol-type ginsenosides such as Re and Rg1 decreased from 7.1 × 104 to 3.0 × 104 ppm and 6.8 × 104 to 4.6 × 104 ppm, respectively. Rg2 and Rh1 increased from 0 to 1.9 × 104 ppm and 0 to 2.7 × 104 ppm, respectively. We can demonstrate that A. niger was more inclined to transform protopanaxadiol-type ginsenosides. Moreover, fermented ginseng extract showed a dramatically enhanced anti-proliferative effect on human HT-29 cell line with a minimum effective concentration of about 1 µg/mL, which might be attributed to the high degree of biotransformation of ginsenosides, especially the high output of ginsenoside cK.
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Affiliation(s)
- Zhipeng Li
- 1Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul, 08826 Korea
| | - Geun Eog Ji
- 1Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul, 08826 Korea.,Research Institute, Bifido Co., Ltd., Hongchun, Gangwon 25117 Korea
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Li Z, Ahn HJ, Kim NY, Lee YN, Ji GE. Korean Ginseng Berry Fermented by Mycotoxin Non-producing Aspergillus niger and Aspergillus oryzae: Ginsenoside Analyses and Anti-proliferative Activities. Biol Pharm Bull 2017; 39:1461-7. [PMID: 27582326 DOI: 10.1248/bpb.b16-00239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To transform ginsenosides, Korean ginseng berry (KGB) was fermented by mycotoxin non-producing Aspergillus niger and Aspergillus oryzae. Changes of ginsenoside profile and anti-proliferative activities were observed. Results showed that A. niger tended to efficiently transform protopanaxadiol (PPD) type ginsenosides such as Rb1, Rb2, Rd to compound K while A. oryzae tended to efficiently transform protopanaxatriol (PPT) type ginsenoside Re to Rh1 via Rg1. Butanol extracts of fermented KGB showed high cytotoxicity on human adenocarcinoma HT-29 cell line and hepatocellular carcinoma HepG2 cell line while that of unfermented KGB showed little. The minimum effective concentration of niger-fermented KGB was less than 2.5 µg/mL while that of oryzae-fermented KGB was about 5 µg/mL. As A. niger is more inclined to transform PPD type ginsenosides, niger-fermented KGB showed stronger anti-proliferative activity than oryzae-fermented KGB.
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Affiliation(s)
- Zhipeng Li
- Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University
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Scientific Opinion on the safety and efficacy of Bacillus subtilis KCCM 10673P and Aspergillus oryzae KCTC 10258BP as feed additives for all animal species. EFSA J 2015. [DOI: 10.2903/j.efsa.2015.4230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Chang PK, Scharfenstein LL, Solorzano CD, Abbas HK, Hua SST, Jones WA, Zablotowicz RM. High sequence variations in the region containing genes encoding a cellular morphogenesis protein and the repressor of sexual development help to reveal origins of Aspergillus oryzae. Int J Food Microbiol 2015; 200:66-71. [PMID: 25689355 DOI: 10.1016/j.ijfoodmicro.2015.01.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 01/21/2015] [Accepted: 01/28/2015] [Indexed: 01/28/2023]
Abstract
Aspergillus oryzae and Aspergillus flavus are closely related fungal species. The A. flavus morphotype that produces numerous small sclerotia (S strain) and aflatoxin has a unique 1.5 kb deletion in the norB-cypA region of the aflatoxin gene cluster (i.e. the S genotype). Phylogenetic studies have indicated that an isolate of the nonaflatoxigenic A. flavus with the S genotype is the ancestor of A. oryzae. Genome sequence comparison between A. flavus NRRL3357, which produces large sclerotia (L strain), and S-strain A. flavus 70S identified a region (samA-rosA) that was highly variable in the two morphotypes. A third type of samA-rosA region was found in A. oryzae RIB40. The three samA-rosA types were later revealed to be commonly present in A. flavus L-strain populations. Of the 182 L-strain A. flavus field isolates examined, 46%, 15% and 39% had the samA-rosA type of NRRL3357, 70S and RIB40, respectively. The three types also were found in 18 S-strain A. flavus isolates with different proportions. For A. oryzae, however, the majority (80%) of the 16 strains examined had the RIB40 type and none had the NRRL3357 type. The results suggested that A. oryzae strains in the current culture collections were mostly derived from the samA-rosA/RIB40 lineage of the nonaflatoxigenic A. flavus with the S genotype.
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Affiliation(s)
- Perng-Kuang Chang
- Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, LA 70124, United States.
| | - Leslie L Scharfenstein
- Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, LA 70124, United States
| | - Cesar D Solorzano
- Biological Control of Pests Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Stoneville, MS 38776, United States
| | - Hamed K Abbas
- Biological Control of Pests Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Stoneville, MS 38776, United States
| | - Sui-Sheng T Hua
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA, 94710, United States
| | - Walker A Jones
- Biological Control of Pests Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Stoneville, MS 38776, United States
| | - Robert M Zablotowicz
- Crop Production Systems Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Stoneville, MS 38776, United States
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Characterization of soybean fermented by aflatoxin non-producing Aspergillus oryzae and γ-aminobutyric acid producing Lactobacillus brevis. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s13765-014-4227-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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