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Abbas A, Prajapati RK, Aalto-Setälä E, Baykov AA, Malinen AM. Aflatoxin biosynthesis regulators AflR and AflS: DNA binding affinity, stoichiometry, and kinetics. Biochem J 2024; 481:805-821. [PMID: 38829003 DOI: 10.1042/bcj20240084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/29/2024] [Accepted: 06/03/2024] [Indexed: 06/05/2024]
Abstract
Aflatoxins (AFs), potent foodborne carcinogens produced by Aspergillus fungi, pose significant health risks worldwide and present challenges to food safety and productivity in the food chain. Novel strategies for disrupting AF production, cultivating resilient crops, and detecting contaminated food are urgently needed. Understanding the regulatory mechanisms of AF production is pivotal for targeted interventions to mitigate toxin accumulation in food and feed. The gene cluster responsible for AF biosynthesis encodes biosynthetic enzymes and pathway-specific regulators, notably AflR and AflS. While AflR, a DNA-binding protein, activates gene transcription within the cluster, AflS enhances AF production through mechanisms that are not fully understood. In this study, we developed protocols to purify recombinant AflR and AflS proteins and utilized multiple assays to characterize their interactions with DNA. Our biophysical analysis indicated that AflR and AflS form a complex. AflS exhibited no DNA-binding capability on its own but unexpectedly reduced the DNA-binding affinity of AflR. Additionally, we found that AflR achieves its binding specificity through a mechanism in which either two copies of AflR or its complex with AflS bind to target sites on DNA in a highly cooperative manner. The estimated values of the interaction parameters of AflR, AflS and DNA target sites constitute a fundamental framework against which the function and mechanisms of other AF biosynthesis regulators can be compared.
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Affiliation(s)
- Asmaa Abbas
- Department of Life Technologies, University of Turku, Turku, Finland
| | | | - Emil Aalto-Setälä
- Department of Life Technologies, University of Turku, Turku, Finland
| | - Alexander A Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Anssi M Malinen
- Department of Life Technologies, University of Turku, Turku, Finland
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2
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Zhang X, Yang Y, Wang L, Qin Y. Histone H2B lysine 122 and lysine 130, as the putative targets of Penicillium oxalicum LaeA, play important roles in asexual development, expression of secondary metabolite gene clusters, and extracellular glycoside hydrolase synthesis. World J Microbiol Biotechnol 2024; 40:179. [PMID: 38668807 DOI: 10.1007/s11274-024-03978-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 04/03/2024] [Indexed: 05/01/2024]
Abstract
Core histones in the nucleosome are subject to a wide variety of posttranslational modifications (PTMs), such as methylation, phosphorylation, ubiquitylation, and acetylation, all of which are crucial in shaping the structure of the chromatin and the expression of the target genes. A putative histone methyltransferase LaeA/Lae1, which is conserved in numerous filamentous fungi, functions as a global regulator of fungal growth, virulence, secondary metabolite formation, and the production of extracellular glycoside hydrolases (GHs). LaeA's direct histone targets, however, were not yet recognized. Previous research has shown that LaeA interacts with core histone H2B. Using S-adenosyl-L-methionine (SAM) as a methyl group donor and recombinant human histone H2B as the substrate, it was found that Penicillium oxalicum LaeA can transfer the methyl groups to the C-terminal lysine (K) 108 and K116 residues in vitro. The H2BK108 and H2BK116 sites on recombinant histone correspond to P. oxalicum H2BK122 and H2BK130, respectively. H2BK122A and H2BK130A, two mutants with histone H2B K122 or K130 mutation to alanine (A), were constructed in P. oxalicum. The mutants H2BK122A and H2BK130A demonstrated altered asexual development and decreased extracellular GH production, consistent with the findings of the laeA gene deletion strain (ΔlaeA). The transcriptome data showed that when compared to wild-type (WT) of P. oxalicum, 38 of the 47 differentially expressed (fold change ≥ 2, FDR ≤ 0.05) genes that encode extracellular GHs showed the same expression pattern in the three mutants ΔlaeA, H2BK122A, and H2BK130A. The four secondary metabolic gene clusters that considerably decreased expression in ΔlaeA also significantly decreased in H2BK122A or H2BK130A. The chromatin of promotor regions of the key cellulolytic genes cel7A/cbh1 and cel7B/eg1 compacted in the ΔlaeA, H2BK122A, and H2BK130A mutants, according to the results of chromatin accessibility real-time PCR (CHART-PCR). The chromatin accessibility index dropped. The histone binding pocket of the LaeA-methyltransf_23 domain is compatible with particular histone H2B peptides, providing appropriate electrostatic and steric compatibility to stabilize these peptides, according to molecular docking. The findings of the study demonstrate that H2BK122 and H2BK130, which are histone targets of P. oxalicum LaeA in vitro, are crucial for fungal conidiation, the expression of gene clusters encoding secondary metabolites, and the production of extracellular GHs.
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Affiliation(s)
- Xiujun Zhang
- National Glycoengineering Research Center, Shandong University, Qingdao, China
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Yuhong Yang
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Yuqi Qin
- National Glycoengineering Research Center, Shandong University, Qingdao, China.
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China.
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Xu J, Jiang M, Wang P, Kong Q. The Gene vepN Regulated by Global Regulatory Factor veA That Affects Aflatoxin Production, Morphological Development and Pathogenicity in Aspergillus flavus. Toxins (Basel) 2024; 16:174. [PMID: 38668599 PMCID: PMC11054512 DOI: 10.3390/toxins16040174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/02/2024] [Accepted: 03/26/2024] [Indexed: 04/29/2024] Open
Abstract
Velvet (VeA), a light-regulated protein that shuttles between the cytoplasm and the nucleus, serves as a key global regulator of secondary metabolism in various Aspergillus species and plays a pivotal role in controlling multiple developmental processes. The gene vepN was chosen for further investigation through CHIP-seq analysis due to significant alterations in its interaction with VeA under varying conditions. This gene (AFLA_006970) contains a Septin-type guanine nucleotide-binding (G) domain, which has not been previously reported in Aspergillus flavus (A. flavus). The functional role of vepN in A. flavus was elucidated through the creation of a gene knockout mutant and a gene overexpression strain using a well-established dual-crossover recombinational technique. A comparison between the wild type (WT) and the ΔvepN mutant revealed distinct differences in morphology, reproductive capacity, colonization efficiency, and aflatoxin production. The mutant displayed reduced growth rate; dispersion of conidial heads; impaired cell wall integrity; and decreased sclerotia formation, colonization capacity, and aflatoxin levels. Notably, ΔvepN exhibited complete growth inhibition under specific stress conditions, highlighting the essential role of vepN in A. flavus. This study provides evidence that vepN positively influences aflatoxin production, morphological development, and pathogenicity in A. flavus.
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Affiliation(s)
- Jia Xu
- School of Food Science and Engineering, Ocean University of China, Qingdao 266404, China; (J.X.); (M.J.)
| | - Mengqi Jiang
- School of Food Science and Engineering, Ocean University of China, Qingdao 266404, China; (J.X.); (M.J.)
| | - Peng Wang
- College of Marine Life Science, Ocean University of China, Qingdao 266003, China;
| | - Qing Kong
- School of Food Science and Engineering, Ocean University of China, Qingdao 266404, China; (J.X.); (M.J.)
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4
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Zhuo Q, Shi C, Geng Q, Wang S, Wang B, Zhang N, Yang K, Tian J. Role of mitochondrial farnesyltransferase gene in the prevention of the food spoilage fungi Aspergillus flavus by the antimicrobial natural preservative perillaldehyde. Food Microbiol 2024; 118:104422. [PMID: 38049276 DOI: 10.1016/j.fm.2023.104422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/24/2023] [Accepted: 11/03/2023] [Indexed: 12/06/2023]
Abstract
Aspergillus flavus, one of the most widely distributed and abundant genus of Aspergillus worldwide, poses an evident threat as a source of food contamination in grains and cereals. Perillaldehyde (PAE), a volatile essential oil extracted from the stem and leaves of Perilla frutescens L., exhibits potent antifungal activity. In our study, we investigated the role of Cox10, a key enzyme in the heme A synthesis pathway crucial for maintaining mitochondrial function. We found that cox10 is a sensitive gene of A. flavus in response to PAE by gene expression assay and GFP fluorescent localization tagging, and then we found that the deletion of this gene affects the growth and development of A. flavus, but the drug resistance is elevated. Through transcriptome sequencing and its experimental validation, the molecular mechanisms of stress triggered by the deletion of cox10 were further clarified, such as the decrease in intracellular drug content due to the increase in the expression of drug efflux proteins, and the increase in the thickness of cell wall due to the increase in the content of cell wall chitin. Clearly, cox10 plays a critical role in regulating various cellular processes of A. flavus, including growth, reproduction, development, as well as pathogenicity and drug resistance. These significant findings establish a solid theoretical foundation for the development of environmentally friendly, safe, and effective antifungal agents to combat A. flavus contamination.
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Affiliation(s)
- Qiuhan Zhuo
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Chenchen Shi
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Qingru Geng
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Shan Wang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Bo Wang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Ninghui Zhang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Kunlong Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
| | - Jun Tian
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, China.
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Zhang X, Guo R, Bi F, Chen Y, Xue X, Wang D. Overexpression of kojR and the entire koj gene cluster affect the kojic acid synthesis in Aspergillus oryzae 3.042. Gene 2024; 892:147852. [PMID: 37776988 DOI: 10.1016/j.gene.2023.147852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/07/2023] [Accepted: 09/27/2023] [Indexed: 10/02/2023]
Abstract
Kojic acid (KA), a fungal secondary metabolite, has various applications in the cosmetics, pharmaceutical, and food industries. Aspergillus oryzae, the primary strain, has been identified as a koj gene cluster positively responsible for KA biosynthesis. In this study, we obtained transformants T58 and T31, which overexpressed either solo kojR or the entire koj gene cluster, respectively. These transformants exhibited peak KA production on the 5th day of shake flask fermentation, with 32.5 g/L and 26.57 g/L that 324.28 % and 246.87 % higher than the control strain with 7.64 g/L, respectively. Morphological analysis revealed that the highly productive KA strains had reduced conidial production but increased antioxidant capacity. The qRT-PCR analysis revealed that relative expression levels of kojR in the transformants were remarkably higher that the primary cause for the increased KA yield. Moreover, the high expression of kojR could also influence the expression of the key enzymes involved in the KA biosynthesis process, such as glucose dehydrogenase and gluconate dehydrogenase. These findings can assist in discovering more about how the koj gene cluster in A. oryzae influences its growth and KA production. And provides valuable insights into facilitating strain improvement and benefits for the future.
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Affiliation(s)
- Xuemei Zhang
- Key Laboratory of Industrial Microbiology & Engineering Research Center of Food Biotechnology of Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Rui Guo
- Key Laboratory of Industrial Microbiology & Engineering Research Center of Food Biotechnology of Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Futi Bi
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006, China.
| | - Yue Chen
- Key Laboratory of Industrial Microbiology & Engineering Research Center of Food Biotechnology of Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Xianli Xue
- Key Laboratory of Industrial Microbiology & Engineering Research Center of Food Biotechnology of Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Tianjin Key Laboratory of Industrial Fermentation Microbiology, Tianjin 300457, China.
| | - Depei Wang
- Key Laboratory of Industrial Microbiology & Engineering Research Center of Food Biotechnology of Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Tianjin Key Laboratory of Industrial Fermentation Microbiology, Tianjin 300457, China.
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Karahoda B, Pfannenstiel BT, Sarikaya-Bayram Ö, Dong Z, Ho Wong K, Fleming AB, Keller NP, Bayram Ö. The KdmB-EcoA-RpdA-SntB (KERS) chromatin regulatory complex controls development, secondary metabolism and pathogenicity in Aspergillus flavus. Fungal Genet Biol 2023; 169:103836. [PMID: 37666447 PMCID: PMC10841535 DOI: 10.1016/j.fgb.2023.103836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/28/2023] [Accepted: 09/01/2023] [Indexed: 09/06/2023]
Abstract
The filamentous fungus Aspergillus flavus is a plant and human pathogen predominantly found in the soil as spores or sclerotia and is capable of producing various secondary metabolites (SM) such as the carcinogenic mycotoxin aflatoxin. Recently, we have discovered a novel nuclear chromatin binding complex (KERS) that contains the JARID1-type histone demethylase KdmB, a putative cohesion acetyl transferase EcoA, a class I type histone deacetylase RpdA and the PHD ring finger reader protein SntB in the model filamentous fungus Aspergillus nidulans. Here, we show the presence of the KERS complex in A. flavus by immunoprecipitation-coupled mass spectrometry and constructed kdmBΔ and rpdAΔ strains to study their roles in fungal development, SM production and histone post-translational modifications (HPTMs). We found that KdmB and RpdA couple the regulation of SM gene clusters with fungal light-responses and HPTMs. KdmB and RpdA have opposing roles in light-induced asexual conidiation, while both factors are positive regulators of sclerotia development through the nsdC and nsdD pathway. KdmB and RpdA are essential for the productions of aflatoxin (similar to findings for SntB) as well as cyclopiazonic acid, ditryptophenaline and leporin B through controlling the respective SM biosynthetic gene clusters. We further show that both KdmB and RpdA regulate H3K4me3 and H3K9me3 levels, while RpdA also acts on H3K14ac levels in nuclear extracts. Therefore, the chromatin modifiers KdmB and RpdA of the KERS complex are key regulators for fungal development and SM metabolism in A. flavus.
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Affiliation(s)
- Betim Karahoda
- Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Brandon T Pfannenstiel
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, USA
| | | | - Zhiqiang Dong
- Faculty of Health Sciences, University of Macau, Macau
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau; Institute of Translational Medicine, University of Macau, Macau; Ministry of Education Frontiers Science Center for Precision Oncology, University of Macau, Macau
| | - Alastair B Fleming
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, USA
| | - Özgür Bayram
- Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland.
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Niu A, Tan L, Tan S, Wang G, Qiu W. The Temporal Dynamics of Sensitivity, Aflatoxin Production, and Oxidative Stress of Aspergillus flavus in Response to Cinnamaldehyde Vapor. Foods 2023; 12:4311. [PMID: 38231749 DOI: 10.3390/foods12234311] [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: 10/25/2023] [Revised: 11/16/2023] [Accepted: 11/23/2023] [Indexed: 01/19/2024] Open
Abstract
Cinnamaldehyde (CA), a natural plant extract, possesses notable antimicrobial properties and the ability to inhibit mycotoxin synthesis. This study investigated the effects of different concentrations of gaseous CA on A. flavus and found that higher concentrations exhibited fungicidal effects, while lower concentrations exerted fungistatic effects. Although all A. flavus strains exhibited similar responses to CA vapor, the degree of response varied among them. Notably, A. flavus strains HN-1, JX-3, JX-4, and HN-8 displayed higher sensitivity. Exposure to CA vapor led to slight damage to A. flavus, induced oxidative stress, and inhibited aflatoxin B1 (AFB1) production. Upon removal of the CA vapor, the damaged A. flavus resumed growth, the oxidative stress weakened, and AFB1 production sharply increased in aflatoxin-producing strains. In the whole process, no aflatoxin was detected in aflatoxin-non-producing A. flavus. Moreover, the qRT-PCR results suggest that the recovery of A. flavus and the subsequent surge of AFB1 content following CA removal were regulated by a drug efflux pump and velvet complex proteins. In summary, these findings emphasize the significance of optimizing the targeted concentrations of antifungal EOs and provide valuable insight for their accurate application.
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Affiliation(s)
- Ajuan Niu
- Key Laboratory of Grains and Oils Quality Control and Processing, Collaborative Innovation Center for Modern Grain Circulation and Safety, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Leilei Tan
- Key Laboratory of Grains and Oils Quality Control and Processing, Collaborative Innovation Center for Modern Grain Circulation and Safety, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Song Tan
- Key Laboratory of Grains and Oils Quality Control and Processing, Collaborative Innovation Center for Modern Grain Circulation and Safety, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Guangyu Wang
- Key Laboratory of Grains and Oils Quality Control and Processing, Collaborative Innovation Center for Modern Grain Circulation and Safety, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Weifen Qiu
- Key Laboratory of Grains and Oils Quality Control and Processing, Collaborative Innovation Center for Modern Grain Circulation and Safety, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China
- Joint Laboratory for International Cooperation in Grain Circulation and Security, Nanjing 210023, China
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Lavkor I, Ay T, Sobucovali S, Var I, Saghrouchni H, Salamatullah AM, Mekonnen AB. Non-Aflatoxigenic Aspergillus flavus: A Promising Biological Control Agent against Aflatoxin Contamination of Corn. ACS OMEGA 2023; 8:16779-16788. [PMID: 37214674 PMCID: PMC10193414 DOI: 10.1021/acsomega.3c00303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/21/2023] [Indexed: 05/24/2023]
Abstract
Aflatoxins (AFs) are a family of mycotoxins produced by molds in agricultural products. To deal with this problem, one of the control methods is the biological solution using a non-pathogenic strain Aspergillus flavus NRRL 21882 (Afla-Guard). This study was conducted to evaluate the potential of A. flavus NRRL 21882 to control the AF contamination of corn in the field and during storage in 2018 and 2019. The experimental design consists of treatment at different vegetative stages of infested corn in the field trial. After the field has been harvested, half the corn kernels from both treated and control plots were treated with biopesticide; the other half of the kernels from each group were not treated and used as the control of the storage. Consequently, storage applications consisted of kernels: (1) not treated at all; (2) treated prior to storage; (3) field-treated; and (4) treated both in the field and prior to storage. After field trials, the AF content was very low in the treated plots, ranging from 0.50 to 1.04 μg/kg and from 0.50 to 0.73 μg/kg in 2018 and 2019, respectively, while the AF content in the control was 98.3 and 73.9 μg/kg in 2018 and 2019, respectively. After storage, corn kernels from field plots that were treated with the biopesticide (treated/control) showed low levels of AFs, even after they have been stored under conditions conducive to AF contamination. The biopesticide effect ranged from 98 to 99% and from 69 to 99% in the field and during storage, respectively. This paper has provided the first indications on AF biocontrol based on a competitive exclusion in the corn-growing region of Turkey. The data showed that spraying during the storage period did not provide any further prevention of AF contamination, and only treatment in the field had a significant effect on AFs that occurred in storage.
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Affiliation(s)
- Isilay Lavkor
- Biological
Control Research Institute, Kisla Cad., 01321 Yüregir, Adana, Türkiye
| | - Tahsin Ay
- Biological
Control Research Institute, Kisla Cad., 01321 Yüregir, Adana, Türkiye
| | - Suat Sobucovali
- Sunar
Mısır Entegre Tesisleri San. ve Tic. A.Ş, Turhan
Cemal Beriker Blv. Yolgeçen mh., Seyhan, 565 01355 Adana, Türkiye
| | - Isil Var
- Molecular
Biology Department, Sussex University, BN1 9RH Brighton, U.K.
| | - Hamza Saghrouchni
- Department
of Biotechnology, Graduate School of Natural and Applied Sciences, Çukurova University, Balcalı, 01250 Adana, Türkiye
| | - Ahmad Mohammad Salamatullah
- Department
of Food Science & Nutrition, College of Food and Agricultural
Sciences, King Saud University, 11 P.O. Box 2460, 11451 Riyadh, Saudi Arabia
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Xie S, Wang C, Zeng T, Wang H, Suo H. Whole-genome and comparative genome analysis of Mucor racemosus C isolated from Yongchuan Douchi. Int J Biol Macromol 2023; 234:123397. [PMID: 36739051 DOI: 10.1016/j.ijbiomac.2023.123397] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/10/2023] [Accepted: 01/18/2023] [Indexed: 02/05/2023]
Abstract
Mucor racemosus is the predominant fungal in the zhiqu stage of the fermentation of Yongchuan Douchi (Mucor-type), which plays an important role in the fermentation process of Yongchuan Douchi. However, there is a lack of information on the genetic analysis of M. racemosus. In this study, we isolated and identified M. racemosus C (accession no JAPEHQ000000000) from Yongchuan Douchi and analyzed the physiological indicators, then genomic information of the strain to perform a comprehensive analysis of its fermentation capacity and safety. M. racemosus C had neutral protease activity up to 68.051 U/mL at 30 °C and alkaline protease activity up to 57.367 U/mL at 25 °C. In addition, comparing the genomic data with the COGs database (NCBI), it was predicted that M. racemosus C undergoes extensive amino acid metabolism, making C suitable for the production of fermented foods (e.g., Douchi, Syoyu, and sufu). Finally, we performed virulence genes and resistance genes analysis, hemolysis experiment, aflatoxins assay, antibiotic resistance assay to evaluate the safety of M. racemosus C, and the results showed that M. racemosus C was safe, non-toxin-producing and non-hemolytic.
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Affiliation(s)
- Shicai Xie
- College of Food Science, Southwest University, Chongqing 400715, China; Food Industry Innovation Research Institute of Modern Sichuan Cuisine & Chongqing Flavor, Chongqing 400715, China
| | - Chen Wang
- College of Food Science, Southwest University, Chongqing 400715, China; Food Industry Innovation Research Institute of Modern Sichuan Cuisine & Chongqing Flavor, Chongqing 400715, China
| | - Tao Zeng
- College of Food Science, Southwest University, Chongqing 400715, China; Food Industry Innovation Research Institute of Modern Sichuan Cuisine & Chongqing Flavor, Chongqing 400715, China
| | - Hongwei Wang
- College of Food Science, Southwest University, Chongqing 400715, China; Food Industry Innovation Research Institute of Modern Sichuan Cuisine & Chongqing Flavor, Chongqing 400715, China
| | - Huayi Suo
- College of Food Science, Southwest University, Chongqing 400715, China; Food Industry Innovation Research Institute of Modern Sichuan Cuisine & Chongqing Flavor, Chongqing 400715, China.
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Dmitrović S, Lukić N, Pajčin I, Vlajkov V, Grahovac J, Jokić A. The Use of Chitosan for Flocculation Recovery of Bacillus Biomass Grown on Dairy and Wine Industry Effluents. Processes (Basel) 2023. [DOI: 10.3390/pr11041099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
The downstream processing of efficient biomass-based microbial biopesticides is heavily reliant on obtaining the largest concentration of viable cells in the most cost-effective manner. The goal of this research was to assess the ability of chitosan flocculation to recover bacterial Bacillus sp. BioSol021 biomass from the broth after biological treatment of wastewaters from the dairy and wine industries. Second-order factorial design models were used to estimate the effect of chitosan concentration and mixing speed on flocculation efficiency, settling velocity, and antimicrobial activity against Aspergillus flavus, i.e., inhibition zone diameter. Response surface methodology was followed by multi-objective optimization by applying the desirability function (DF) and genetic algorithm (GA). The optimum values for flocculation efficiency, settling velocity, and inhibition zone diameter for cheese whey effluent were 88%, 0.10 mm/s, and 51.00 mm, respectively. In the case of winery flotation effluent, the optimum values were flocculation efficiency 95% and settling velocity 0.05 mm/s, while the inhibition zone diameter was 48.00 mm. These results indicate that utilizing chitosan as a flocculation agent not only fits the criteria for effective downstream processing, but also has a synergistic effect on Bacillus sp. antibacterial activity.
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Affiliation(s)
- Selena Dmitrović
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Nataša Lukić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Ivana Pajčin
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Vanja Vlajkov
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Jovana Grahovac
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Aleksandar Jokić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
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11
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Loi M, Logrieco AF, Pusztahelyi T, Leiter É, Hornok L, Pócsi I. Advanced mycotoxin control and decontamination techniques in view of an increased aflatoxin risk in Europe due to climate change. Front Microbiol 2023; 13:1085891. [PMID: 36762096 PMCID: PMC9907446 DOI: 10.3389/fmicb.2022.1085891] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/15/2022] [Indexed: 01/11/2023] Open
Abstract
Aflatoxins are toxic secondary metabolites produced by Aspergillus spp. found in staple food and feed commodities worldwide. Aflatoxins are carcinogenic, teratogenic, and mutagenic, and pose a serious threat to the health of both humans and animals. The global economy and trade are significantly affected as well. Various models and datasets related to aflatoxins in maize have been developed and used but have not yet been linked. The prevention of crop loss due to aflatoxin contamination is complex and challenging. Hence, the set-up of advanced decontamination is crucial to cope with the challenge of climate change, growing population, unstable political scenarios, and food security problems also in European countries. After harvest, decontamination methods can be applied during transport, storage, or processing, but their application for aflatoxin reduction is still limited. Therefore, this review aims to investigate the effects of environmental factors on aflatoxin production because of climate change and to critically discuss the present-day and novel decontamination techniques to unravel gaps and limitations to propose them as a tool to tackle an increased aflatoxin risk in Europe.
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Affiliation(s)
- Martina Loi
- Institute of Sciences of Food Production, National Research Council, Bari, Italy,*Correspondence: Martina Loi, ✉
| | - Antonio F. Logrieco
- Institute of Sciences of Food Production, National Research Council, Bari, Italy
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
| | - Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, Institute of Biotechnology, University of Debrecen, Debrecen, Hungary,ELRN-UD Fungal Stress Biology Research Group, University of Debrecen, Debrecen, Hungary
| | - László Hornok
- Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, Institute of Biotechnology, University of Debrecen, Debrecen, Hungary,ELRN-UD Fungal Stress Biology Research Group, University of Debrecen, Debrecen, Hungary
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12
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Quorum-Sensing Inhibitors from Probiotics as a Strategy to Combat Bacterial Cell-to-Cell Communication Involved in Food Spoilage and Food Safety. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8120711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Experience-based knowledge has shown that bacteria can communicate with each other through a cell-density-dependent mechanism called quorum sensing (QS). QS controls specific bacterial phenotypes, such as sporulation, virulence and pathogenesis, the production of degrading enzymes, bioluminescence, swarming motility, and biofilm formation. The expression of these phenotypes in food spoiling and pathogenic bacteria, which may occur in food, can have dramatic consequences on food production, the economy, and health. Due to the many reports showing that the use of conventional methods (i.e., antibiotics and sanitizers) to inhibit bacterial growth leads to the emergence of antibiotic resistance, it is necessary to research and exploit new strategies. Several studies have already demonstrated positive results in this direction by inhibiting autoinducers (low-molecular-weight signaling compounds controlling QS) and by other means, leading to QS inhibition via a mechanism called quorum quenching (QQ). Thus far, several QS inhibitors (QSIs) have been isolated from various sources, such as plants, some animals from aqueous ecosystems, fungi, and bacteria. The present study aims to discuss the involvement of QS in food spoilage and to review the potential role of probiotics as QSIs.
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13
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Itaconic acid production is regulated by LaeA in Aspergillus pseudoterreus. Metab Eng Commun 2022; 15:e00203. [PMID: 36065328 PMCID: PMC9440423 DOI: 10.1016/j.mec.2022.e00203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/08/2022] [Accepted: 08/15/2022] [Indexed: 11/22/2022] Open
Abstract
The global regulator LaeA controls secondary metabolism in diverse Aspergillus species. Here we explored its role in regulation of itaconic acid production in Aspergillus pseudoterreus. To understand its role in regulating metabolism, we deleted and overexpressed laeA, and assessed the transcriptome, proteome, and secreted metabolome prior to and during initiation of phosphate limitation induced itaconic acid production. We found that secondary metabolite clusters, including the itaconic acid biosynthetic gene cluster, are regulated by laeA and that laeA is required for high yield production of itaconic acid. Overexpression of LaeA improves itaconic acid yield at the expense of biomass by increasing the expression of key biosynthetic pathway enzymes and attenuating the expression of genes involved in phosphate acquisition and scavenging. Increased yield was observed in optimized conditions as well as conditions containing excess nutrients that may be present in inexpensive sugar containing feedstocks such as excess phosphate or complex nutrient sources. This suggests that global regulators of metabolism may be useful targets for engineering metabolic flux that is robust to environmental heterogeneity. The Itaconic acid biosynthetic gene cluster is regulated by laeA. LaeA is required for production of itaconic acid. Overexpression of laeA attenuates genes involved in phosphate acquisition. Global regulator engineering increases robustness of itaconic acid production.
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14
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Dmitrović S, Pajčin I, Vlajkov V, Grahovac M, Jokić A, Grahovac J. Dairy and Wine Industry Effluents as Alternative Media for the Production of Bacillus-Based Biocontrol Agents. Bioengineering (Basel) 2022; 9:663. [PMID: 36354577 PMCID: PMC9687624 DOI: 10.3390/bioengineering9110663] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/25/2022] [Accepted: 11/03/2022] [Indexed: 01/07/2024] Open
Abstract
Food industry effluents represent one of the major concerns when it comes to environmental impact; hence, their valorization through different chemical and biological routes has been suggested as a possible solution. The vast amount of organic and inorganic nutrients present in food industry effluents makes them suitable substrates for microbial growth. This study suggests two valorization routes for whey as dairy industry effluent and flotation wastewater from the wine industry through microbial conversion to biocontrol agents as value-added products. Cultivations of the biocontrol strain Bacillus sp. BioSol021 were performed in a 16 L bioreactor to monitor the bioprocess course and investigate bioprocess kinetics in terms of microbial growth, sugar substrate consumption and surfactin synthesis, as an antimicrobial lipopeptide. The produced biocontrol agents showed high levels of biocontrol activity against mycotoxigenic strains of Aspergillus flavus, followed by a significant reduction of sugar load of the investigated effluents by the producing microorganisms. With proven high potential of whey and winery flotation wastewater to be used as substrates for microbial growth, this study provides grounds for further optimization of the suggested valorization routes, mostly in terms of bioprocess conditions to achieve maximal techno-economical feasibility, energy saving and maximal reduction of effluents' organic and inorganic burden.
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Affiliation(s)
- Selena Dmitrović
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Ivana Pajčin
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Vanja Vlajkov
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Mila Grahovac
- Faculty of Agriculture, University of Novi Sad, Trg Dositeja Obradovića 8, 21000 Novi Sad, Serbia
| | - Aleksandar Jokić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Jovana Grahovac
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
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15
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Kumar P, Gupta A, Mahato DK, Pandhi S, Pandey AK, Kargwal R, Mishra S, Suhag R, Sharma N, Saurabh V, Paul V, Kumar M, Selvakumar R, Gamlath S, Kamle M, Enshasy HAE, Mokhtar JA, Harakeh S. Aflatoxins in Cereals and Cereal-Based Products: Occurrence, Toxicity, Impact on Human Health, and Their Detoxification and Management Strategies. Toxins (Basel) 2022; 14:toxins14100687. [PMID: 36287956 PMCID: PMC9609140 DOI: 10.3390/toxins14100687] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/08/2022] Open
Abstract
Cereals and cereal-based products are primary sources of nutrition across the world. However, contamination of these foods with aflatoxins (AFs), secondary metabolites produced by several fungal species, has raised serious concerns. AF generation in innate substrates is influenced by several parameters, including the substrate type, fungus species, moisture content, minerals, humidity, temperature, and physical injury to the kernels. Consumption of AF-contaminated cereals and cereal-based products can lead to both acute and chronic health issues related to physical and mental maturity, reproduction, and the nervous system. Therefore, the precise detection methods, detoxification, and management strategies of AFs in cereal and cereal-based products are crucial for food safety as well as consumer health. Hence, this review provides a brief overview of the occurrence, chemical characteristics, biosynthetic processes, health hazards, and detection techniques of AFs, along with a focus on detoxification and management strategies that could be implemented for food safety and security.
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Affiliation(s)
- Pradeep Kumar
- Department of Botany, University of Lucknow, Lucknow 226007, India
- Applied Microbiology Laboratory, Department of Forestry, North Eastern Regional Institute of Science and Technology, Nirjuli 791109, India
- Correspondence: (P.K.); (D.K.M.)
| | - Akansha Gupta
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
- CASS Food Research Centre, School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Dipendra Kumar Mahato
- CASS Food Research Centre, School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC 3125, Australia
- Correspondence: (P.K.); (D.K.M.)
| | - Shikha Pandhi
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Arun Kumar Pandey
- MMICT&BM(HM), Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala 133207, India
| | - Raveena Kargwal
- Department of Processing and Food Engineering, College of Agricultural Engineering and Technology, Chaudhary Charan Singh Haryana Agricultural University, Hisar 125004, India
| | - Sadhna Mishra
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
- Faculty of Agricultural Sciences, GLA University, Mathura 281406, India
| | - Rajat Suhag
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano, Italy
| | - Nitya Sharma
- Food and Bioprocess Engineering Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Vivek Saurabh
- Division of Food Science and Postharvest Technology, ICAR—Indian Agricultural Research Institute, New Delhi 110012, India
| | - Veena Paul
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Manoj Kumar
- Chemical and Biochemical Processing Division, ICAR—Central Institute for Research on Cotton Technology, Mumbai 400019, India
| | - Raman Selvakumar
- Centre for Protected Cultivation Technology, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi 110012, India
| | - Shirani Gamlath
- CASS Food Research Centre, School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Madhu Kamle
- Applied Microbiology Laboratory, Department of Forestry, North Eastern Regional Institute of Science and Technology, Nirjuli 791109, India
| | - Hesham Ali El Enshasy
- Institute of Bioproduct Development, Universiti Teknologi Malaysia (UTM), Skudai 81310, Malaysia
- City of Scientific Research and Technology Applications, New Burg Al Arab, Alexandria 21934, Egypt
| | - Jawahir A. Mokhtar
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University Hospital, Jeddah 21589, Saudi Arabia
- Vaccines and Immunotherapy Unit, King Fahad Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Steve Harakeh
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Yousef Abdul Latif Jameel Scientific Chair of Prophetic Medicine Application, Faculty of Medicine (FM), King Abdulaziz University, Jeddah 21589, Saudi Arabia
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16
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Schüller A, Studt-Reinhold L, Strauss J. How to Completely Squeeze a Fungus-Advanced Genome Mining Tools for Novel Bioactive Substances. Pharmaceutics 2022; 14:1837. [PMID: 36145585 PMCID: PMC9505985 DOI: 10.3390/pharmaceutics14091837] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/23/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022] Open
Abstract
Fungal species have the capability of producing an overwhelming diversity of bioactive substances that can have beneficial but also detrimental effects on human health. These so-called secondary metabolites naturally serve as antimicrobial "weapon systems", signaling molecules or developmental effectors for fungi and hence are produced only under very specific environmental conditions or stages in their life cycle. However, as these complex conditions are difficult or even impossible to mimic in laboratory settings, only a small fraction of the true chemical diversity of fungi is known so far. This also implies that a large space for potentially new pharmaceuticals remains unexplored. We here present an overview on current developments in advanced methods that can be used to explore this chemical space. We focus on genetic and genomic methods, how to detect genes that harbor the blueprints for the production of these compounds (i.e., biosynthetic gene clusters, BGCs), and ways to activate these silent chromosomal regions. We provide an in-depth view of the chromatin-level regulation of BGCs and of the potential to use the CRISPR/Cas technology as an activation tool.
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Affiliation(s)
| | | | - Joseph Strauss
- Institute of Microbial Genetics, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna, A-3430 Tulln/Donau, Austria
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17
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Wang L, Liu J, Li X, Lyu X, Liu Z, Zhao H, Jiao X, Zhang W, Xie J, Liu W. A histone H3K9 methyltransferase Dim5 mediates repression of sorbicillinoid biosynthesis in Trichoderma reesei. Microb Biotechnol 2022; 15:2533-2546. [PMID: 35921310 PMCID: PMC9518983 DOI: 10.1111/1751-7915.14103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/05/2022] [Indexed: 11/27/2022] Open
Abstract
Sorbicillinoids (also termed yellow pigment) are derived from either marine or terrestrial fungi, exhibit various biological activities and therefore show potential as commercial products for human or animal health. The cellulolytic filamentous fungus Trichoderma reesei is capable to biosynthesize sorbicillinoids, but the underlying regulatory mechanism is not yet completely clear. Herein, we identified a histone H3 lysine 9 (H3K9) methyltransferase, Dim5, in T. reesei. TrDIM5 deletion caused an impaired vegetative growth as well as conidiation, whereas the ∆Trdim5 strain displayed a remarkable increase in sorbicillinoid production. Post TrDIM5 deletion, the transcription of sorbicillinoid biosynthesis‐related (SOR) genes was significantly upregulated with a more open chromatin structure. Intriguingly, hardly any expression changes occurred amongst those genes located on both flanks of the SOR gene cluster. In addition, the assays provided evidence that H3K9 triple methylation (H3K9me3) modification acted as a repressive marker at the SOR gene cluster and thus directly mediated the repression of sorbicillinoid biosynthesis. Transcription factor Ypr1 activated the SOR gene cluster by antagonizing TrDim5‐mediated repression and therefore contributed to forming a relatively more open local chromatin environment, which further facilitated its binding and SOR gene expression. The results of this study will contribute to understanding the intricate regulatory network in sorbicillinoid biosynthesis and facilitate the endowment of T. reesei with preferred features for sorbicillinoid production by genetic engineering.
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Affiliation(s)
- Lei Wang
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Jialong Liu
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Xiaotong Li
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Xinxing Lyu
- Institute of Basic Medicine, Shandong First Medical University&Shandong Academy of Medical Sciences, Jinan, China
| | - Zhizhen Liu
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Hong Zhao
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Xiangying Jiao
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Weixin Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Jun Xie
- Collaborative Innovation Center of Reverse Microbial Etiology, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
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18
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CRISPR/Cas9-Based Genome Editing and Its Application in Aspergillus Species. J Fungi (Basel) 2022; 8:jof8050467. [PMID: 35628723 PMCID: PMC9143064 DOI: 10.3390/jof8050467] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
Aspergillus, a genus of filamentous fungi, is extensively distributed in nature and plays crucial roles in the decomposition of organic materials as an important environmental microorganism as well as in the traditional fermentation and food processing industries. Furthermore, due to their strong potential to secrete a large variety of hydrolytic enzymes and other natural products by manipulating gene expression and/or introducing new biosynthetic pathways, several Aspergillus species have been widely exploited as microbial cell factories. In recent years, with the development of next-generation genome sequencing technology and genetic engineering methods, the production and utilization of various homo-/heterologous-proteins and natural products in Aspergillus species have been well studied. As a newly developed genome editing technology, the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system has been used to edit and modify genes in Aspergilli. So far, the CRISPR/Cas9-based approach has been widely employed to improve the efficiency of gene modification in the strain type Aspergillus nidulans and other industrially important and pathogenic Aspergillus species, including Aspergillus oryzae, Aspergillus niger, and Aspergillus fumigatus. This review highlights the current development of CRISPR/Cas9-based genome editing technology and its application in basic research and the production of recombination proteins and natural products in the Aspergillus species.
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19
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Abbas A, Wright CW, El-Sawi N, Yli-Mattila T, Malinen AM. A methanolic extract of Zanthoxylum bungeanum modulates secondary metabolism regulator genes in Aspergillus flavus and shuts down aflatoxin production. Sci Rep 2022; 12:5995. [PMID: 35397670 PMCID: PMC8994782 DOI: 10.1038/s41598-022-09913-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 03/29/2022] [Indexed: 12/30/2022] Open
Abstract
Aflatoxin B1 (AFB1) is a food-borne toxin produced by Aspergillus flavus and a few similar fungi. Natural anti-aflatoxigenic compounds are used as alternatives to chemical fungicides to prevent AFB1 accumulation. We found that a methanolic extract of the food additive Zanthoxylum bungeanum shuts down AFB1 production in A. flavus. A methanol sub-fraction (M20) showed the highest total phenolic/flavonoid content and the most potent antioxidant activity. Mass spectrometry analyses identified four flavonoids in M20: quercetin, epicatechin, kaempferol-3-O-rhamnoside, and hyperoside. The anti-aflatoxigenic potency of M20 (IC50: 2-4 µg/mL) was significantly higher than its anti-proliferation potency (IC50: 1800-1900 µg/mL). RNA-seq data indicated that M20 triggers significant transcriptional changes in 18 of 56 secondary metabolite pathways in A. flavus, including repression of the AFB1 biosynthesis pathway. Expression of aflR, the specific activator of the AFB1 pathway, was not changed by M20 treatment, suggesting that repression of the pathway is mediated by global regulators. Consistent with this, the Velvet complex, a prominent regulator of secondary metabolism and fungal development, was downregulated. Decreased expression of the conidial development regulators brlA and Medusa, genes that orchestrate redox responses, and GPCR/oxylipin-based signal transduction further suggests a broad cellular response to M20. Z. bungeanum extracts may facilitate the development of safe AFB1 control strategies.
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Affiliation(s)
- Asmaa Abbas
- Department of Life Technologies, University of Turku, 20014, Turku, Finland.,School of Pharmacy and Medical Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK.,Department of Chemistry, Faculty of Science, Sohag University, Sohag, 82524, Egypt
| | - Colin W Wright
- School of Pharmacy and Medical Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK
| | - Nagwa El-Sawi
- Department of Chemistry, Faculty of Science, Sohag University, Sohag, 82524, Egypt
| | - Tapani Yli-Mattila
- Department of Life Technologies, University of Turku, 20014, Turku, Finland
| | - Anssi M Malinen
- Department of Life Technologies, University of Turku, 20014, Turku, Finland.
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20
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Ma X, Jiang Y, Ma L, Luo S, Du H, Li X, Xing F. Corepressors SsnF and RcoA Regulate Development and Aflatoxin B1 Biosynthesis in Aspergillus flavus NRRL 3357. Toxins (Basel) 2022; 14:toxins14030174. [PMID: 35324671 PMCID: PMC8954095 DOI: 10.3390/toxins14030174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 02/04/2023] Open
Abstract
Aspergillus flavus is a saprophytic fungus that can be found across the entire world. It can produce aflatoxin B1 (AFB1), which threatens human health. CreA, as the central factor in carbon catabolite repression (CCR), regulates carbon catabolism and AFB1 biosynthesis in A. flavus. Additionally, SsnF-RcoA are recognized as the corepressors of CreA in CCR. In this study, ssnF and rcoA not only regulated the expressions of CCR factors and hydrolase genes, but also positively affected mycelia growth, conidia production, sclerotia formation, and osmotic stress response in A. flavus. More importantly, SsnF and RcoA were identified as positive regulators for AFB1 biosynthesis, as they modulate the AF cluster genes and the relevant regulators at a transcriptional level. Additionally, the interactions of SsnF-CreA and RcoA-CreA were strong and moderate, respectively. However, the interaction of SsnF and RcoA was weak. The interaction models of CreA-SsnF, CreA-RcoA, and SsnF-RcoA were also simulated with a docking analysis. All things considered, SsnF and RcoA are not just the critical regulators of the CCR pathway, but the global regulators involving in morphological development and AFB1 biosynthesis in A. flavus.
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Affiliation(s)
| | | | | | | | | | - Xu Li
- Correspondence: (X.L.); (F.X.)
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21
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Chakraborty P. Gene cluster from plant to microbes: Their role in genome architecture, organism's development, specialized metabolism and drug discovery. Biochimie 2021; 193:1-15. [PMID: 34890733 DOI: 10.1016/j.biochi.2021.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/01/2021] [Accepted: 12/04/2021] [Indexed: 02/07/2023]
Abstract
Plants and microbes fulfil our daily requirements through different high-value chemicals, e.g., nutraceuticals, pharmaceuticals, cosmetics, and through varieties of fruits, crops, vegetables, and many more. Utmost care would therefore be taken for growth, development and sustainability of these important crops and medicinal plants and microbes. Homeobox genes and HOX clusters and their recently characterized expanded family members, including newly discovered homeobox, WOX gene from medicinal herb, Panax ginseng, significantly contributes in the growth and development of these organisms. On the other hand, secondary metabolites produced through secondary metabolism of plants and microbes are used as organisms defense as well as drugs/drug-like molecules for humans. Both the developmental HOX cluster and the biosynthetic gene-cluster (BGC) for secondary metabolites are organised in organisms genome. Genome mining and genomewide analysis of these clusters will definitely identify and characterize many more important molecules from unexplored plants and microbes and underexplored human microbiota and the evolution studies of these clusters will indicate their source of origin. Although genomics revolution now continues at a pace, till date only few hundred plant genome sequences are available. However, next-generation sequencing (NGS) technology now in market and may be applied even for plants with recalcitrant genomes, eventually may discover genomic potential towards production of secondary metabolites of diverse plants and micro-organisms present in the environment and microbiota. Additionally, the development of tools for genome mining e.g., antiSMASH, plantiSMASH, and more and more computational approaches that predicts hundreds of secondary metabolite BGCs will be discussed.
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Affiliation(s)
- Prasanta Chakraborty
- Kalpana Chawla Center for Space and Nanoscience, Kolkata, Indian Institute of Chemical Biology (retd.), Kolkata, 700032, India.
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22
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Zaman GS, Kamli H, Radhakrishnan S, Ahmad I, Otifi H, Alshahrani MY, Rajagopalan P. Structure activity evaluation and computational analysis identify potent, novel 3-benzylidene chroman-4-one analogs with anti-fungal, anti-oxidant, and anti-cancer activities. Drug Dev Ind Pharm 2021; 47:1459-1468. [PMID: 34726982 DOI: 10.1080/03639045.2021.2001489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
SIGNIFICANCE 3-Benzylidene chroman-4-ones share close homology with naturally occurring bioactive compounds. OBJECTIVES This study evaluated the antifungal, antioxidant, and anticancer activities of novel 3-benzylidene chromanone analogs with respect to their structure-activity relationships. METHODS Compounds 45e-64e were synthesized inhouse. Aspergillus niger (MTCC 1344) Aspergillus flavus and Botrytis cinerea were the fungal strains tested. Computational docking analysis was carried out for vanin-1, estrogen receptor (ER), and Akt proteins using Auto-dock vina. Free radical scavenging and total antioxidant capacity was analyzed using spectrophotometric methods. MCF-7 (breast cancer) cell line was used for anticancer assays. Flow cytometry was used to detect cell cycle and apoptosis. RESULTS Out of the twenty compounds screened, compounds 47e, 50e, 52e, 57e, and 61e that possessed either methoxy and ethoxy/methyl/isopropyl group exhibited very good activity against all fungi. Compounds possessing methoxy group alone showed moderate activity and compounds devoid of methoxy, and ethoxy groups did not show any activity. When computationally analyzed against target proteins for antioxidant properties, the compounds exhibited excellent binging efficacy to vanin-1 and ERs. These predictions were translated in the in vitro free-radical scavenging and antioxidant assays. The compounds exhibited anti-proliferative efficacy in breast cancer cell line, increased the sub-G0/G1 cell cycle populations and total apoptosis in MCF-7 cells. Additionally, the compounds also depicted excelling binging energy when computationally analyzed for Akt enzyme binding. CONCLUSION In summary, our study identified potential analogs of 3-benzylidene chroman-4-one molecules with excellent anti-fungal, anti-oxidant, and anticancer activities which demand further research for drug developments.
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Affiliation(s)
- Gaffar Sarwar Zaman
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Hossam Kamli
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Suresh Radhakrishnan
- Post Graduate and Research Department of Chemistry, Presidency College, Chennai, India
| | - Irfan Ahmad
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Hassan Otifi
- Department of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Mohamad Y Alshahrani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Prasanna Rajagopalan
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia.,Central Research Laboratory, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
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Balbinot RB, de Oliveira JAM, Bernardi DI, Polli AD, Polonio JC, Cabral MRP, Zanqueta ÉB, Endo EH, Meneguello JE, Cardoso RF, Azevedo JL, Dias Filho BP, Nakamura TU, do Carmo MRB, Sarragiotto MH, Pamphile JA, Baldoqui DC. Chromolaena laevigata (Asteraceae) as a source of endophytic non-aflatoxigenic Aspergillus flavus: chemical profile in different culture conditions and biological applications. Braz J Microbiol 2021; 52:1201-1214. [PMID: 33929720 PMCID: PMC8324641 DOI: 10.1007/s42770-021-00502-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 04/16/2021] [Indexed: 10/21/2022] Open
Abstract
Endophytes are microorganisms that form symbiotic relationships with their host. These microorganisms can produce a variety of secondary metabolites, some of which have inhibitory effects on pests and pathogens or even act to promote plant growth. Due to these characteristics, these microorganisms are used as sources of biologically active substances for a wide range of biotechnological applications. Based on that, the aim of this study was to evaluate the production of metabolites of the endophytic Aspergillus flavus CL7 isolated from Chromolaena laevigata, in four different cultivation conditions, and to determine the antimicrobial, cytotoxic, antiviral, and antioxidant potential of these extracts. The multiphasic approach used to identify this strain was based on morphology and ITS gene sequence analysis. The chemical investigation of A. flavus using potato dextrose and minimal medium, using both stationary and agitated methods, resulted in the isolation of kojic acid, α-cyclopiazonic acid, and 20,25-dihydroxyaflavinine. Another 18 compounds in these extracts were identified by UHPLC-HRMS/MS, of which dideacetyl parasiticolide A has been described for the first time from A. flavus. Aflatoxins, important chemomarkers of A. flavus, were not detected in any of the extracts, thus indicating that the CL7 strain is non-aflatoxigenic. The biological potential of all extracts was evaluated, and the best results were observed for the extract obtained using minimal medium against Trichophyton rubrum and Mycobacterium tuberculosis.
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Affiliation(s)
- Rodolfo B Balbinot
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Josiane A M de Oliveira
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Darlon I Bernardi
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Andressa D Polli
- Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Julio C Polonio
- Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Márcia R P Cabral
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Érica B Zanqueta
- Departamento de Ciências Básicas da Saúde, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Eliana H Endo
- Departamento de Ciências Básicas da Saúde, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Jean E Meneguello
- Departamento de Análises Clínicas e Biomedicina, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Rosilene F Cardoso
- Departamento de Análises Clínicas e Biomedicina, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - João L Azevedo
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz - ESALQ/USP, Universidade de São Paulo, Av. Pádua Dias 11, 13418-900, Piracicaba, São Paulo, Brazil
| | - Benedito P Dias Filho
- Departamento de Ciências Básicas da Saúde, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Tania U Nakamura
- Departamento de Ciências Básicas da Saúde, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Marta R B do Carmo
- Departamento de Biologia Geral, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4778, 84030-910, Ponta Grossa, Paraná, Brazil
| | - Maria H Sarragiotto
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - João A Pamphile
- Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil
| | - Debora C Baldoqui
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná, Brazil.
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Skerker JM, Pianalto KM, Mondo SJ, Yang K, Arkin AP, Keller NP, Grigoriev IV, Louise Glass NL. Chromosome assembled and annotated genome sequence of Aspergillus flavus NRRL 3357. G3 (BETHESDA, MD.) 2021; 11:6310016. [PMID: 34849826 PMCID: PMC8496237 DOI: 10.1093/g3journal/jkab213] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/10/2021] [Indexed: 01/22/2023]
Abstract
Aspergillus flavus is an opportunistic pathogen of crops, including peanuts and maize, and is the second leading cause of aspergillosis in immunocompromised patients. A. flavus is also a major producer of the mycotoxin, aflatoxin, a potent carcinogen, which results in significant crop losses annually. The A. flavus isolate NRRL 3357 was originally isolated from peanut and has been used as a model organism for understanding the regulation and production of secondary metabolites, such as aflatoxin. A draft genome of NRRL 3357 was previously constructed, enabling the development of molecular tools and for understanding population biology of this particular species. Here, we describe an updated, near complete, telomere-to-telomere assembly and re-annotation of the eight chromosomes of A. flavus NRRL 3357 genome, accomplished via long-read PacBio and Oxford Nanopore technologies combined with Illumina short-read sequencing. A total of 13,715 protein-coding genes were predicted. Using RNA-seq data, a significant improvement was achieved in predicted 5’ and 3’ untranslated regions, which were incorporated into the new gene models.
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Affiliation(s)
- Jeffrey M Skerker
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kaila M Pianalto
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Stephen J Mondo
- The U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Kunlong Yang
- Department of Medical Microbiology & Immunology and Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| | - Adam P Arkin
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA.,Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Nancy P Keller
- Department of Medical Microbiology & Immunology and Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| | - Igor V Grigoriev
- The U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - N Louise Louise Glass
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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25
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Leiter É, Emri T, Pákozdi K, Hornok L, Pócsi I. The impact of bZIP Atf1ortholog global regulators in fungi. Appl Microbiol Biotechnol 2021; 105:5769-5783. [PMID: 34302199 PMCID: PMC8390427 DOI: 10.1007/s00253-021-11431-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 11/09/2022]
Abstract
Regulation of signal transduction pathways is crucial for the maintenance of cellular homeostasis and organismal development in fungi. Transcription factors are key elements of this regulatory network. The basic-region leucine zipper (bZIP) domain of the bZIP-type transcription factors is responsible for DNA binding while their leucine zipper structural motifs are suitable for dimerization with each other facilitiating the formation of homodimeric or heterodimeric bZIP proteins. This review highlights recent knowledge on the function of fungal orthologs of the Schizosaccharomyces pombe Atf1, Aspergillus nidulans AtfA, and Fusarium verticillioides FvAtfA, bZIP-type transcription factors with a special focus on pathogenic species. We demonstrate that fungal Atf1-AtfA-FvAtfA orthologs play an important role in vegetative growth, sexual and asexual development, stress response, secondary metabolite production, and virulence both in human pathogens, including Aspergillus fumigatus, Mucor circinelloides, Penicillium marneffei, and Cryptococcus neoformans and plant pathogens, like Fusarium ssp., Magnaporthe oryzae, Claviceps purpurea, Botrytis cinerea, and Verticillium dahliae. KEY POINTS: • Atf1 orthologs play crucial role in the growth and development of fungi. • Atf1 orthologs orchestrate environmental stress response of fungi. • Secondary metabolite production and virulence are coordinated by Atf1 orthologs.
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Affiliation(s)
- Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary.
| | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary
| | - Klaudia Pákozdi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary
| | - László Hornok
- Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, University of Debrecen, P.O. Box 63, Debrecen, H-4010, Hungary
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26
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Aflatoxin Biosynthesis, Genetic Regulation, Toxicity, and Control Strategies: A Review. J Fungi (Basel) 2021; 7:jof7080606. [PMID: 34436145 PMCID: PMC8397101 DOI: 10.3390/jof7080606] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 12/24/2022] Open
Abstract
Aflatoxins (AFs) are highly toxic and cancer-causing compounds, predominantly synthesized by the Aspergillus species. AFs biosynthesis is a lengthy process that requires as minimum as 30 genes grouped inside 75 kilobytes (kB) of gene clusters, which are regulated by specific transcription factors, including aflR, aflS, and some general transcription factors. This paper summarizes the status of research on characterizing structural and regulatory genes associated with AF production and their roles in aflatoxigenic fungi, particularly Aspergillus flavus and A. parasiticus, and enhances the current understanding of AFs that adversely affect humans and animals with a great emphasis on toxicity and preventive methods.
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27
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Hu Z, Yuan K, Zhou Q, Lu C, Du L, Liu F. Mechanism of antifungal activity of Perilla frutescens essential oil against Aspergillus flavus by transcriptomic analysis. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107703] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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28
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Wang C, Xu F, Baker R, Pinjari A, Bruckers L, Zhao Y, Stevenson A, Zhang G. Fungi carried over in jute bags – a smoking gun for aflatoxin contamination in the food supply chain. WORLD MYCOTOXIN J 2021. [DOI: 10.3920/wmj2020.2619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
India is the largest jute and fifth largest maize producing country in the world. In India maize is commonly stored and transported in jute bags which are used multiple times. Aflatoxin contamination of maize is a major issue in India. This study evaluated the potential impact of re-using jute bags on the risk of aflatoxin contamination of maize in the food supply chain. A total of 121 jute bags were collected in India; 95 had been used for maize and 26 bags were new. Significantly higher numbers of viable aflatoxigenic fungi were counted from re-used bags (27.8 times) (P<0.05), than the number from new bags. There was no significant difference between aflatoxin concentration found in the re-used jute bags and the new jute bags (P>0.05). Further analysis revealed that the aflatoxigenic fungal population (3.0 times) and aflatoxin concentration (1.2 times) were significantly higher in jute bags that had been used for maize with higher aflatoxin contamination (14-188.4 μg/kg total aflatoxins) than in those that had been used for maize with lower contamination (0.8-5.4 μg/kg total aflatoxins) (P<0.05). The significant positive correlation (P<0.05) between the aflatoxigenic fungal population of used jute bags and aflatoxin contamination of their packed maize indicated there is a risk of cross-contamination in the supply chain introduced by re-using jute bags. This is the first study to systematically reveal the potential impact of re-using jute bags on the fungal population and aflatoxin contamination risk. The application of readily applied treatments to re-used jute bags would help to minimise the aflatoxin contamination.
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Affiliation(s)
- C. Wang
- Mars Global Food Safety Center, Mars Inc., Yanqi Economic Development Zone, Huairou, Beijing 101407, China P.R
| | - F. Xu
- Mars Global Food Safety Center, Mars Inc., Yanqi Economic Development Zone, Huairou, Beijing 101407, China P.R
| | - R.C. Baker
- Mars Global Food Safety Center, Mars Inc., Yanqi Economic Development Zone, Huairou, Beijing 101407, China P.R
| | - A. Pinjari
- Mars International India Pvt, Ltd, Avusulonipally village, Wargal Mandal, Siddipet Distt. Telangana State, 502279, India
| | - L. Bruckers
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics, University Hasselt, Agoralaan Building D, 3590 Diepenbeek, Belgium
| | - Y. Zhao
- Mars Global Food Safety Center, Mars Inc., Yanqi Economic Development Zone, Huairou, Beijing 101407, China P.R
| | - A. Stevenson
- Mars Global Food Safety Center, Mars Inc., Yanqi Economic Development Zone, Huairou, Beijing 101407, China P.R
| | - G. Zhang
- Mars Global Food Safety Center, Mars Inc., Yanqi Economic Development Zone, Huairou, Beijing 101407, China P.R
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Sun R, Wen M, Wu L, Lan H, Yuan J, Wang S. The Fungi-specific histone Acetyltransferase Rtt109 mediates morphogenesis, Aflatoxin synthesis and pathogenicity in Aspergillus flavus by acetylating H3K9. IMA Fungus 2021; 12:9. [PMID: 33823938 PMCID: PMC8025522 DOI: 10.1186/s43008-021-00060-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 03/21/2021] [Indexed: 11/26/2022] Open
Abstract
Aspergillus flavus is a common saprophytic filamentous fungus that produces the highly toxic natural compound aflatoxin during its growth process. Synthesis of the aflatoxins, which can contaminate food crops causing huge losses to the agricultural economy, is often regulated by epigenetic modification, such as the histone acetyltransferase. In this study, we used Aspergillus flavus as an experimental model to construct the acetyltransferase gene rtt109 knockout strain (△rtt109) and its complementary strain (△rtt109·com) by homologous recombination. The growth of △rtt109 was significantly suppressed compared to the wild type (WT) strain and the △rtt109·com strain. The sclerotium of △rtt109 grew smaller, and the amount of sclerotia generated by △rtt109 was significantly reduced. The number of conidiums of △rtt109 was significantly reduced, especially on the yeast extract sucrose (YES) solid medium. The amount of aflatoxins synthesized by △rtt109 in the PDB liquid medium was significantly decreased We also found that the △rtt109 strain was extremely sensitive to DNA damage stress. Through the maize seed infection experiment, we found that the growth of △rtt109 on the surface of affected corn was largely reduced, and the amount of aerial mycelium decreased significantly, which was consistent with the results on the artificial medium. We further found that H3K9 was the acetylated target of Rtt109 in A. flavus. In conclusion, Rtt109 participated in the growth, conidium formation, sclerotia generation, aflatoxin synthesis, environmental stress response, regulation of infection of A. flavus. The results from this study of rtt109 showed data for acetylation in the regulation of life processes and provided a new thought regarding the prevention and control of A. flavus hazards.
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Affiliation(s)
- Ruilin Sun
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Meifang Wen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lianghuan Wu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Huahui Lan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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Jin FJ, Hu S, Wang BT, Jin L. Advances in Genetic Engineering Technology and Its Application in the Industrial Fungus Aspergillus oryzae. Front Microbiol 2021; 12:644404. [PMID: 33708187 PMCID: PMC7940364 DOI: 10.3389/fmicb.2021.644404] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/05/2021] [Indexed: 12/19/2022] Open
Abstract
The filamentous fungus Aspergillus oryzae is an important strain in the traditional fermentation and food processing industries and is often used in the production of soy sauce, soybean paste, and liquor-making. In addition, A. oryzae has a strong capacity to secrete large amounts of hydrolytic enzymes; therefore, it has also been used in the enzyme industry as a cell factory for the production of numerous native and heterologous enzymes. However, the production and secretion of foreign proteins by A. oryzae are often limited by numerous bottlenecks that occur during transcription, translation, protein folding, translocation, degradation, transport, secretion, etc. The existence of these problems makes it difficult to achieve the desired target in the production of foreign proteins by A. oryzae. In recent years, with the decipherment of the whole genome sequence, basic research and genetic engineering technologies related to the production and utilization of A. oryzae have been well developed, such as the improvement of homologous recombination efficiency, application of selectable marker genes, development of large chromosome deletion technology, utilization of hyphal fusion techniques, and application of CRISPR/Cas9 genome editing systems. The development and establishment of these genetic engineering technologies provided a great deal of technical support for the industrial production and application of A. oryzae. This paper reviews the advances in basic research and genetic engineering technologies of the fermentation strain A. oryzae mentioned above to open up more effective ways and research space for the breeding of A. oryzae production strains in the future.
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Affiliation(s)
- Feng-Jie Jin
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Shuang Hu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Bao-Teng Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Long Jin
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
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Tian F, Lee SY, Woo SY, Choi HY, Heo S, Nah G, Chun HS. Transcriptomic responses of Aspergillus flavus to temperature and oxidative stresses during aflatoxin production. Sci Rep 2021; 11:2803. [PMID: 33531617 PMCID: PMC7854668 DOI: 10.1038/s41598-021-82488-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/18/2021] [Indexed: 01/30/2023] Open
Abstract
Aflatoxin is a group of polyketide-derived carcinogenic and mutagenic secondary metabolites produced by Aspergillus flavus that negatively impact global food security and threaten the health of both humans and livestock. Aflatoxin biosynthesis is strongly affected by the fungal developmental stage, cultivation conditions, and environmental stress. In this study, a novel float culture method was used to examine the direct responses of the A. flavus transcriptome to temperature stress, oxidative stress, and their dual effects during the aflatoxin production stage. The transcriptomic response of A. flavus illustrated that the co-regulation of different secondary metabolic pathways likely contributes to maintaining cellular homeostasis and promoting cell survival under stress conditions. In particular, aflatoxin biosynthetic gene expression was downregulated, while genes encoding secondary metabolites with antioxidant properties, such as kojic acid and imizoquins, were upregulated under stress conditions. Multiple mitochondrial function-related genes, including those encoding NADH:ubiquinone oxidoreductase, ubiquinol-cytochrome C reductase, and alternative oxidase, were differentially expressed. These data can provide insights into the important mechanisms through which secondary metabolism in A. flavus is co-regulated and facilitate the deployment of various approaches for the effective control and prevention of aflatoxin contamination in food crops.
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Affiliation(s)
- Fei Tian
- grid.254224.70000 0001 0789 9563Food Toxicology Laboratory, School of Food Science and Technology, Chung-Ang University, Anseong, Korea
| | - Sang Yoo Lee
- grid.254224.70000 0001 0789 9563Food Toxicology Laboratory, School of Food Science and Technology, Chung-Ang University, Anseong, Korea
| | - So Young Woo
- grid.254224.70000 0001 0789 9563Food Toxicology Laboratory, School of Food Science and Technology, Chung-Ang University, Anseong, Korea
| | - Hwa Young Choi
- grid.254224.70000 0001 0789 9563Food Toxicology Laboratory, School of Food Science and Technology, Chung-Ang University, Anseong, Korea
| | - Seongeun Heo
- grid.254224.70000 0001 0789 9563Food Toxicology Laboratory, School of Food Science and Technology, Chung-Ang University, Anseong, Korea
| | - Gyoungju Nah
- grid.31501.360000 0004 0470 5905Genome Analysis Center at National Instrumentation Center for Environmental Management, Seoul National University, Seoul, Korea
| | - Hyang Sook Chun
- grid.254224.70000 0001 0789 9563Food Toxicology Laboratory, School of Food Science and Technology, Chung-Ang University, Anseong, Korea
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Li J, Zhi QQ, Zhang J, Yuan XY, Jia LH, Wan YL, Liu QY, Shi JR, He ZM. Synthetic antimicrobial agents inhibit aflatoxin production. Braz J Microbiol 2021; 52:821-835. [PMID: 33447936 DOI: 10.1007/s42770-021-00423-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 01/05/2021] [Indexed: 11/25/2022] Open
Abstract
Antimicrobial peptides (AMPs) are biologically active molecules that can eradicate bacteria by destroying the bacterial membrane structure, causing the bacteria to rupture. However, little is known about the extent and effect of AMPs on filamentous fungi. In this study, we synthesized small molecular polypeptides by an inexpensive heat conjugation approach and examined their effects on the growth of Aspergillus flavus and its secondary metabolism. The antimicrobial agents significantly inhibited aflatoxin production, conidiation, and sclerotia formation in A. flavus. Furthermore, we found that the expression of aflatoxin structural genes was significantly inhibited, and the intracellular reactive oxygen species (ROS) level was reduced. Additionally, the antimicrobial agents can change membrane permeability. Overall, our results demonstrated that antimicrobial agents, safe to mammalian cells, have an obvious impact on aflatoxin production, which indicated that antimicrobial agents may be adopted as a new generation of potential agents for controlling aflatoxin contamination.
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Affiliation(s)
- Jing Li
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Qing-Qing Zhi
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Jie Zhang
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Xiao-Yu Yuan
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Li-Hong Jia
- The Guangdong Provincial Key Laboratory for Biotechnology Drug Candidates, School of Bioscience and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Yu-Lin Wan
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Qiu-Yun Liu
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Jian-Rong Shi
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing, 210000, China.
| | - Zhu-Mei He
- The Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
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Ssu72 Regulates Fungal Development, Aflatoxin Biosynthesis and Pathogenicity in Aspergillus flavus. Toxins (Basel) 2020; 12:toxins12110717. [PMID: 33202955 PMCID: PMC7696088 DOI: 10.3390/toxins12110717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 12/18/2022] Open
Abstract
The RNA polymerase II (Pol II) transcription process is coordinated by the reversible phosphorylation of its largest subunit-carboxy terminal domain (CTD). Ssu72 is identified as a CTD phosphatase with specificity for phosphorylation of Ser5 and Ser7 and plays critical roles in regulation of transcription cycle in eukaryotes. However, the biofunction of Ssu72 is still unknown in Aspergillus flavus, which is a plant pathogenic fungus and produces one of the most toxic mycotoxins-aflatoxin. Here, we identified a putative phosphatase Ssu72 and investigated the function of Ssu72 in A. flavus. Deletion of ssu72 resulted in severe defects in vegetative growth, conidiation and sclerotia formation. Additionally, we found that phosphatase Ssu72 positively regulates aflatoxin production through regulating expression of aflatoxin biosynthesis cluster genes. Notably, seeds infection assays indicated that phosphatase Ssu72 is crucial for pathogenicity of A. flavus. Furthermore, the Δssu72 mutant exhibited more sensitivity to osmotic and oxidative stresses. Taken together, our study suggests that the putative phosphatase Ssu72 is involved in fungal development, aflatoxin production and pathogenicity in A. flavus, and may provide a novel strategy to prevent the contamination of this pathogenic fungus.
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Qin L, Li D, Zhao J, Yang G, Wang Y, Yang K, Tumukunde E, Wang S, Yuan J. The membrane mucin Msb2 regulates aflatoxin biosynthesis and pathogenicity in fungus Aspergillus flavus. Microb Biotechnol 2020; 14:628-642. [PMID: 33159717 PMCID: PMC7936294 DOI: 10.1111/1751-7915.13701] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
As a pathogenic fungus, Aspergillus flavus can produce carcinogenic aflatoxins (AFs), which poses a great threat to crops and animals. Msb2, the signalling mucin protein, is a part of mitogen‐activated protein kinase (MAPK) pathway which contributes to a range of physiological processes. In this study, the roles of membrane mucin Msb2 were explored in A. flavus by the application of gene disruption. The deletion of msb2 gene (Δmsb2) caused defects in vegetative growth, sporulation and sclerotia formation when compared to WT and complement strain (Δmsb2C) in A. flavus. Using thin‐layer chromatography (TLC) and high‐performance liquid chromatography (HPLC) analysis, it was found that deletion of msb2 down‐regulated aflatoxin B1 (AFB1) synthesis and decreased the infection capacity of A. flavus. Consistently, Msb2 responds to cell wall stress and osmotic stress by positively regulating the phosphorylation of MAP kinase. Notably, Δmsb2 mutant exhibited cell wall defect, and it was more sensitive to inhibitor caspofungin when compared to WT and Δmsb2C. Taking together, these results revealed that Msb2 plays key roles in morphological development process, stresses adaptation, secondary metabolism and pathogenicity in fungus A. flavus.
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Affiliation(s)
- Ling Qin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ding Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jiaru Zhao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Guang Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yinchun Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Kunlong Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Elisabeth Tumukunde
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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Evaluation of the chemical constituents and potential biological activities of Cunninghamella blakesleeana. Saudi Pharm J 2020; 28:1197-1202. [PMID: 33132713 PMCID: PMC7584793 DOI: 10.1016/j.jsps.2020.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/11/2020] [Indexed: 11/17/2022] Open
Abstract
The aim of this work is to evaluate the chemical constituents and potential biological activists of Cunninghamella blakesleeana. Three fatty acids were isolated using column chromatography and identified as palmitic acid (F1), oleic acid (F2) and stearic acid (F3) in addition to other two steroidal compounds; α-amyrin (A4), and β-sitosterol (A5). Using GC, ten fatty acids were detected the major fatty acid obtained was stearic acid (74.61%) while palmitic acid was the second high percentage (10.35%), and the least percentage obtained was arachidic acid (0.07%). C. blakesleeana extract showed in-vitro antimicrobial activities against some microorganisms. The highest activity of C. blakesleeana total extract was reported against Staphylococcus aureus (18.3 ± 0.03 mm.) followed by Streptococcus pyogenes (15.3 ± 0.05), while the lowest were for both Candida albicans & Pseudomonas aeruginosa (6.7 ± 0.06 and 5.9.0 ± 0.9 mm. respectively). The three isolated compounds (F1-3) showed activities against Staphylococcus aureus, Penicillium expansum, and Salmonella typhimurium only. The highest activity was aganist Staphylococcus aureus (13.0 ± 0.1 mm.). The highest effect was obtained by compound F3 (stearic acid) (15.0 ± 0.5 mm.), and compound F1 (oleic acid) (13.0 ± 0.1 mm.) and F2 (palmitic acid) 11.0 ± 0.3 mm. The total ethanol extract of the investigated fungus was safe up to 5000 mg kg−1 and did not produce any significant change in liver and kidney functions after oral administration (400 mg kg−1) for 14 consecutive days. The results reported the isolation of some fungal new driving compounds which has been not isolated before from Cunninghamella species in addition to their correlated new biological activities.
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Uka V, Cary JW, Lebar MD, Puel O, De Saeger S, Diana Di Mavungu J. Chemical repertoire and biosynthetic machinery of the Aspergillus flavus secondary metabolome: A review. Compr Rev Food Sci Food Saf 2020; 19:2797-2842. [PMID: 33337039 DOI: 10.1111/1541-4337.12638] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/18/2022]
Abstract
Filamentous fungi represent a rich source of extrolites, including secondary metabolites (SMs) comprising a great variety of astonishing structures and interesting bioactivities. State-of-the-art techniques in genome mining, genetic manipulation, and secondary metabolomics have enabled the scientific community to better elucidate and more deeply appreciate the genetic and biosynthetic chemical arsenal of these microorganisms. Aspergillus flavus is best known as a contaminant of food and feed commodities and a producer of the carcinogenic family of SMs, aflatoxins. This fungus produces many SMs including polyketides, ribosomal and nonribosomal peptides, terpenoids, and other hybrid molecules. This review will discuss the chemical diversity, biosynthetic pathways, and biological/ecological role of A. flavus SMs, as well as their significance concerning food safety and security.
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Affiliation(s)
- Valdet Uka
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.,Division of Pharmacy, Faculty of Medicine, University of Pristina, Pristina, Kosovo
| | - Jeffrey W Cary
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana
| | - Matthew D Lebar
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Sarah De Saeger
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - José Diana Di Mavungu
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
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37
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Bisceglie F, Degola F, Rogolino D, Giannelli G, Orsoni N, Spadola G, Pioli M, Restivo FM, Carcelli M, Pelosi G. Sisters in structure but different in character, some benzaldehyde and cinnamaldehyde derivatives differentially tune Aspergillus flavus secondary metabolism. Sci Rep 2020; 10:17686. [PMID: 33077881 PMCID: PMC7572373 DOI: 10.1038/s41598-020-74574-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/30/2020] [Indexed: 01/07/2023] Open
Abstract
Great are the expectations for a new generation of antimicrobials, and strenuous are the research efforts towards the exploration of diverse molecular scaffolds-possibly of natural origin - aimed at the synthesis of new compounds against the spread of hazardous fungi. Also high but winding are the paths leading to the definition of biological targets specifically fitting the drug's structural characteristics. The present study is addressed to inspect differential biological behaviours of cinnamaldehyde and benzaldehyde thiosemicarbazone scaffolds, exploiting the secondary metabolism of the mycotoxigenic phytopathogen Aspergillus flavus. Interestingly, owing to modifications on the parent chemical scaffold, some thiosemicarbazones displayed an increased specificity against one or more developmental processes (conidia germination, aflatoxin biosynthesis, sclerotia production) of A. flavus biology. Through the comparative analysis of results, the ligand-based screening strategy here described has allowed us to delineate which modifications are more promising for distinct purposes: from the control of mycotoxins contamination in food and feed commodities, to the environmental management of microbial pathogens, to the investigation of specific structure-activity features for new generation drug discovery.
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Affiliation(s)
- Franco Bisceglie
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Francesca Degola
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Dominga Rogolino
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Gianluigi Giannelli
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Nicolò Orsoni
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Giorgio Spadola
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Marianna Pioli
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Francesco M. Restivo
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Mauro Carcelli
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Giorgio Pelosi
- grid.10383.390000 0004 1758 0937Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
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38
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Li X, Jiang Y, Ma L, Ma X, Liu Y, Shan J, Ma K, Xing F. Comprehensive Transcriptome and Proteome Analyses Reveal the Modulation of Aflatoxin Production by Aspergillus flavus on Different Crop Substrates. Front Microbiol 2020; 11:1497. [PMID: 32760360 PMCID: PMC7371938 DOI: 10.3389/fmicb.2020.01497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/09/2020] [Indexed: 01/26/2023] Open
Abstract
As a natural severe contaminant of stored grains and other crops worldwide, Aspergillus flavus can produce aflatoxins (AFs), the most powerful naturally producing toxic and hepatocarcinogenic compounds. AFs production is regulated by diverse factors including AFs cluster genes, transcription factors, regulators, and environmental factors. Among them, crop substrate is one of the most important factors. Here, we found that AFB1 production was significantly higher in maize and rice broth than in peanut broth. To clarify the mechanisms involved, complementary transcriptomic and proteomic analyses were performed to identify changes in A. flavus incubated in the three crop substrates. The results indicated that fewer genes and proteins were differentially expressed between maize and rice substrates, whereas more differentially expressed genes were observed between maize/rice broth and peanut broth. In particular, the genes involved in the initial step of AFs biosynthesis (aflA, aflB, and aflC) and the ACCase-encoding gene accA were significantly upregulated on the maize and rice substrates. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses indicated that carbon-metabolism-related genes were obviously enriched in the maize broth, and the genes involved in acetyl-CoA accumulation and consumption were up- and downregulated, respectively. Several genes involved in the regulation of AFs biosynthesis, including veA, ppoB, snf1, and the G-protein-coupled receptor (GPCR) genes, were differentially expressed on the three substrates, suggesting that these genes may be also involved in sugar signal sensing, transfer, and regulation. Interestingly, by the correlation analyses of transcriptome and proteome, trehalose metabolism genes, aldehyde dehydrogenase gene, and tryptophan synthase gene were found to be relevant with the regulation of AFs production on different crop substrates. Taken together, the differential expressions of the AFs cluster genes, several regulatory genes, and carbon metabolism genes were involved in the comprehensive modulation of AFs production on different crop substrates.
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Affiliation(s)
- Xu Li
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiran Jiang
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Longxue Ma
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoyun Ma
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yang Liu
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China.,School of Food Science and Engineering, Foshan University, Foshan, China
| | - Jihao Shan
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kang Ma
- Division of Chemical Metrology and Analytical Science, National Institute of Metrology, Beijing, China
| | - Fuguo Xing
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
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39
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Masiello M, Somma S, Haidukowski M, Logrieco AF, Moretti A. Genetic polymorphisms associated to SDHI fungicides resistance in selected Aspergillus flavus strains and relation with aflatoxin production. Int J Food Microbiol 2020; 334:108799. [PMID: 32799117 DOI: 10.1016/j.ijfoodmicro.2020.108799] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/17/2020] [Accepted: 07/24/2020] [Indexed: 12/18/2022]
Abstract
Aspergillus flavus is a common and ubiquitous fungal species able to colonize several agricultural commodities, in both pre- and post-harvest conditions. This species represents a very harmful plant pathogen for its ability to synthesize aflatoxin B1, responsible for human primary hepatocellular carcinoma and classified as a group I (human carcinogenic) by the International Agency for Research on Cancer. Several approaches have been proposed to control A. flavus development and related aflatoxin production in field and storage conditions. The Succinate Dehydrogenase Inhibitor (SDHI) fungicide boscalid has been shown to control A. flavus growth and aflatoxin contamination both in vitro and in field experiments. However, this compound is classified as medium-high risk fungicide for triggering fungal resistance and, indeed, resistant strains can occur on crops treated with boscalid. In this paper, we selected laboratory A. flavus strains resistant to boscalid grown on agar medium containing 50 mg/L of boscalid. In order to investigate the molecular mechanism responsible for the resistant phenotype, specific primer pairs were designed to amplify the whole SdhB, SdhC and SdhD genes. By amino acid sequence analysis, two point mutations, Tyrosine replacing Histidine at codon 249 of SdhB (H249Y) and Arginine replacing Glycine at codon 91 of SdhC (G91R), were identified. The effect of SDHI boscalid and isopyrazam on mycelial growth and conidial germination was evaluated. Both resistant genotypes showed high resistance (MIC and EC50 > 1000 mg/L) to boscalid. A positive cross-resistance was found between boscalid and isopyrazam. Specific sub-lethal doses of both fungicides (0.5 mg/L of boscalid and 0.01 mg/L of isopyrazam) interfered with the mechanisms associated to pigmentation of colonies. In particular, fungal colonies appeared depigmented lacking the typical A. flavus green colour shown on un-amended fungicide medium. A strict correlation between lack of pigmentation and increasing aflatoxin production was also observed.
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Affiliation(s)
- M Masiello
- Institute of Sciences of Food Production, Research National Council (ISPA-CNR), Via Amendola 122/O, 70126 Bari, Italy.
| | - S Somma
- Institute of Sciences of Food Production, Research National Council (ISPA-CNR), Via Amendola 122/O, 70126 Bari, Italy.
| | - M Haidukowski
- Institute of Sciences of Food Production, Research National Council (ISPA-CNR), Via Amendola 122/O, 70126 Bari, Italy.
| | - A F Logrieco
- Institute of Sciences of Food Production, Research National Council (ISPA-CNR), Via Amendola 122/O, 70126 Bari, Italy.
| | - A Moretti
- Institute of Sciences of Food Production, Research National Council (ISPA-CNR), Via Amendola 122/O, 70126 Bari, Italy.
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40
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Drott MT, Satterlee TR, Skerker JM, Pfannenstiel BT, Glass NL, Keller NP, Milgroom MG. The Frequency of Sex: Population Genomics Reveals Differences in Recombination and Population Structure of the Aflatoxin-Producing Fungus Aspergillus flavus. mBio 2020; 11:e00963-20. [PMID: 32665272 PMCID: PMC7360929 DOI: 10.1128/mbio.00963-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
The apparent rarity of sex in many fungal species has raised questions about how much sex is needed to purge deleterious mutations and how differences in frequency of sex impact fungal evolution. We sought to determine how differences in the extent of recombination between populations of Aspergillus flavus impact the evolution of genes associated with the synthesis of aflatoxin, a notoriously potent carcinogen. We sequenced the genomes of, and quantified aflatoxin production in, 94 isolates of A. flavus sampled from seven states in eastern and central latitudinal transects of the United States. The overall population is subdivided into three genetically differentiated populations (A, B, and C) that differ greatly in their extent of recombination, diversity, and aflatoxin-producing ability. Estimates of the number of recombination events and linkage disequilibrium decay suggest relatively frequent sex only in population A. Population B is sympatric with population A but produces significantly less aflatoxin and is the only population where the inability of nonaflatoxigenic isolates to produce aflatoxin was explained by multiple gene deletions. Population expansion evident in population B suggests a recent introduction or range expansion. Population C is largely nonaflatoxigenic and restricted mainly to northern sampling locations through restricted migration and/or selection. Despite differences in the number and type of mutations in the aflatoxin gene cluster, codon optimization and site frequency differences in synonymous and nonsynonymous mutations suggest that low levels of recombination in some A. flavus populations are sufficient to purge deleterious mutations.IMPORTANCE Differences in the relative frequencies of sexual and asexual reproduction have profound implications for the accumulation of deleterious mutations (Muller's ratchet), but little is known about how these differences impact the evolution of ecologically important phenotypes. Aspergillus flavus is the main producer of aflatoxin, a notoriously potent carcinogen that often contaminates food. We investigated if differences in the levels of production of aflatoxin by A. flavus could be explained by the accumulation of deleterious mutations due to a lack of recombination. Despite differences in the extent of recombination, variation in aflatoxin production is better explained by the demography and history of specific populations and may suggest important differences in the ecological roles of aflatoxin among populations. Furthermore, the association of aflatoxin production and populations provides a means of predicting the risk of aflatoxin contamination by determining the frequencies of isolates from low- and high-production populations.
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Affiliation(s)
- Milton T Drott
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tatum R Satterlee
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jeffrey M Skerker
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
| | | | - N Louise Glass
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
- Department of Plant and Microbial Biology, The University of California, Berkeley, California, USA
- Environmental Genomics and Systems Biology, The Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, USA
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41
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Musungu B, Bhatnagar D, Quiniou S, Brown RL, Payne GA, O’Brian G, Fakhoury AM, Geisler M. Use of Dual RNA-seq for Systems Biology Analysis of Zea mays and Aspergillus flavus Interaction. Front Microbiol 2020; 11:853. [PMID: 32582038 PMCID: PMC7285840 DOI: 10.3389/fmicb.2020.00853] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 04/09/2020] [Indexed: 11/18/2022] Open
Abstract
The interaction between Aspergillus flavus and Zea mays is complex, and the identification of plant genes and pathways conferring resistance to the fungus has been challenging. Therefore, the authors undertook a systems biology approach involving dual RNA-seq to determine the simultaneous response from the host and the pathogen. What was dramatically highlighted in the analysis is the uniformity in the development patterns of gene expression of the host and the pathogen during infection. This led to the development of a "stage of infection index" that was subsequently used to categorize the samples before down-stream system biology analysis. Additionally, we were able to ascertain that key maize genes in pathways such as the jasmonate, ethylene and ROS pathways, were up-regulated in the study. The stage of infection index used for the transcriptomic analysis revealed that A. flavus produces a relatively limited number of transcripts during the early stages (0 to 12 h) of infection. At later stages, in A. flavus, transcripts and pathways involved in endosomal transport, aflatoxin production, and carbohydrate metabolism were up-regulated. Multiple WRKY genes targeting the activation of the resistance pathways (i.e., jasmonate, phenylpropanoid, and ethylene) were detected using causal inference analysis. This analysis also revealed, for the first time, the activation of Z. mays resistance genes influencing the expression of specific A. flavus genes. Our results show that A. flavus seems to be reacting to a hostile environment resulting from the activation of resistance pathways in Z. mays. This study revealed the dynamic nature of the interaction between the two organisms.
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Affiliation(s)
- Bryan Musungu
- Department of Plant Biology, Southern Illinois University, Carbondale, IL, United States
| | - Deepak Bhatnagar
- Southern Regional Research Center, USDA-ARS, New Orleans, LA, United States
| | - Sylvie Quiniou
- Warm Water Aquaculture Research Unit, USDA-ARS, Stoneville, MS, United States
| | - Robert L. Brown
- Southern Regional Research Center, USDA-ARS, New Orleans, LA, United States
| | - Gary A. Payne
- Department of Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Greg O’Brian
- Department of Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Ahmad M. Fakhoury
- Department of Plant Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, United States
| | - Matt Geisler
- Department of Plant Biology, Southern Illinois University, Carbondale, IL, United States
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42
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Spadola G, Sanna V, Bartoli J, Carcelli M, Pelosi G, Bisceglie F, Restivo FM, Degola F, Rogolino D. Thiosemicarbazone nano-formulation for the control of Aspergillus flavus. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:20125-20135. [PMID: 32239408 DOI: 10.1007/s11356-020-08532-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/20/2020] [Indexed: 05/27/2023]
Abstract
Nanoparticles are widely studied for applications in medical science. In recent years, they have been developed for agronomical purposes to target microbial pest such as bacteria, fungi, and viruses. Nanoparticles are also proposed to limit the use of pesticides, whose abuse is causing environmental impact and human health concerns. In this study, nanoparticles were obtained by using poly-(ε-caprolactone), a polyester chosen for its biocompatibility and biodegradability properties. Poly-(ε-caprolactone) nanoparticles were formulated by using poly(vinyl alcohol) or Pluronic® F127 as non-ionic surfactants, and then loaded with benzophenone or valerophenone thiosemicarbazone, two compounds that inhibit aflatoxin production by Aspergillus flavus. The different types of nanoparticles were compared in terms of size, polydispersity index, morphology, and drug loading capacity. Finally, their effects were investigated on growth, development, and aflatoxin production in the aflatoxigenic species Aspergillus flavus, a ubiquitous contaminant of maize, cereal crops, and derived commodities. Aflatoxin production was inhibited to various extents, but the best inhibitory effect was obtained with respect to sclerotia production that was most effectively suppressed by both benzophenone and valerophenone thiosemicarbazone-loaded nanoparticles. These data support the idea that it is possible to use such nanoparticles as an alternate to pesticides for the control of mycotoxigenic sclerotia-forming fungi.
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Affiliation(s)
- Giorgio Spadola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Vanna Sanna
- Nanomater Srl Porto Conte Ricerche, Loc. Tramariglio, 07041, Alghero, SS, Italy
| | - Jennifer Bartoli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Mauro Carcelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Giorgio Pelosi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Franco Bisceglie
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Francesco Maria Restivo
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Francesca Degola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy
| | - Dominga Rogolino
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124, Parma, Italy.
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43
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Nazhand A, Durazzo A, Lucarini M, Souto EB, Santini A. Characteristics, Occurrence, Detection and Detoxification of Aflatoxins in Foods and Feeds. Foods 2020; 9:E644. [PMID: 32443392 PMCID: PMC7278662 DOI: 10.3390/foods9050644] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/14/2022] Open
Abstract
Mycotoxin contamination continues to be a food safety concern globally, with the most toxic being aflatoxins. On-farm aflatoxins, during food transit or storage, directly or indirectly result in the contamination of foods, which affects the liver, immune system and reproduction after infiltration into human beings and animals. There are numerous reports on aflatoxins focusing on achieving appropriate methods for quantification, precise detection and control in order to ensure consumer safety. In 2012, the International Agency for Research on Cancer (IARC) classified aflatoxins B1, B2, G1, G2, M1 and M2 as group 1 carcinogenic substances, which are a global human health concern. Consequently, this review article addresses aflatoxin chemical properties and biosynthetic processes; aflatoxin contamination in foods and feeds; health effects in human beings and animals due to aflatoxin exposure, as well as aflatoxin detection and detoxification methods.
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Affiliation(s)
- Amirhossein Nazhand
- Department of Biotechnology, Sari Agricultural Science and Natural Resource University, 9th km of Farah Abad Road, Mazandaran 48181-68984, Iran;
| | - Alessandra Durazzo
- CREA-Research Centre for Food and Nutrition, Via Ardeatina 546, 00178 Roma, Italy; (A.D.); (M.L.)
| | - Massimo Lucarini
- CREA-Research Centre for Food and Nutrition, Via Ardeatina 546, 00178 Roma, Italy; (A.D.); (M.L.)
| | - Eliana B. Souto
- Faculty of Pharmacy of University of Coimbra, Azinhaga de Santa Comba, Polo III-Saúde, 3000-548 Coimbra, Portugal;
- CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Antonello Santini
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy
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44
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Frawley D, Stroe MC, Oakley BR, Heinekamp T, Straßburger M, Fleming AB, Brakhage AA, Bayram Ö. The Pheromone Module SteC-MkkB-MpkB-SteD-HamE Regulates Development, Stress Responses and Secondary Metabolism in Aspergillus fumigatus. Front Microbiol 2020; 11:811. [PMID: 32457716 PMCID: PMC7223695 DOI: 10.3389/fmicb.2020.00811] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
In order for eukaryotes to efficiently detect and respond to environmental stimuli, a myriad of protein signaling pathways are utilized. An example of highly conserved signaling pathways in eukaryotes are the mitogen-activated protein kinase (MAPK) pathways. In fungi, MAPK pathways have been shown to regulate a diverse array of biological processes, such as asexual and sexual development, stress responses and the production of secondary metabolites (SMs). In the model fungus Aspergillus nidulans, a MAPK pathway known as the pheromone module is utilized to regulate both development and SM production. This signaling cascade consists of the three kinases SteC, MkkB, and MpkB, as well as the SteD adaptor protein and the HamE scaffold. In this study, homologs of each of these proteins have been identified in the opportunistic human pathogen A. fumigatus. By performing epitope tagging and mass spectrometry experiments, we have shown that these proteins form a pentameric complex, similar to what is observed in A. nidulans. This complex has been shown to assemble in the cytoplasm and MpkB enters the nucleus, where it would presumably interact with various transcription factors. Pheromone module mutant strains exhibit drastic reductions in asexual sporulation, vegetative growth rate and production of SMs, such as gliotoxin. Mutants also display increased sensitivity to cell wall and oxidative stress agents. Overall, these data provide evidence of the existence of a conserved MAP kinase signaling pathway in Aspergillus species and suggest that this pathway is critical for the regulation of fungal development and secondary metabolism.
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Affiliation(s)
- Dean Frawley
- Department of Biology, Fungal Genetics and Secondary Metabolism Laboratory, Maynooth University, Maynooth, Ireland
| | - Maria C Stroe
- Department of Molecular and Applied Microbiology, Hans Knöll Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Berl R Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States
| | - Thorsten Heinekamp
- Department of Molecular and Applied Microbiology, Hans Knöll Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Maria Straßburger
- Transfer Group Antiinfectives, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Alastair B Fleming
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Hans Knöll Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Özgür Bayram
- Department of Biology, Fungal Genetics and Secondary Metabolism Laboratory, Maynooth University, Maynooth, Ireland
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45
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Frawley D, Bayram Ö. Identification of SkpA-CulA-F-box E3 ligase complexes in pathogenic Aspergilli. Fungal Genet Biol 2020; 140:103396. [PMID: 32325169 DOI: 10.1016/j.fgb.2020.103396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 11/29/2022]
Abstract
The ubiquitin proteasome system is critical for the regulation of protein turnover, which is implicated in the modulation of a wide array of biological processes in eukaryotes, ranging from cell senescence to virulence in plant and human hosts. Proteins to be marked for ubiquitination and subsequent degradation are bound by F-box proteins, which are interchangeable substrate-recognising receptors. These F-box proteins bind a wide range of substrates and associate with the adaptor protein Skp1 and the scaffold Cul1 to form Skp1-Cul1-F-box (SCF) complexes. SCF complex components are highly conserved in eukaryotes, ranging from yeast to humans. However, information regarding the composition of these complexes and the biological roles of F-box proteins is limited, specifically in filamentous fungal species like the genus Aspergillus. In this study, we have identified 51 and 55 fbx-encoding genes in the genomes of two pathogenic fungi, A. fumigatus and A. flavus, respectively. Immunoprecipitations of the HA-tagged SkpA adaptor protein revealed that 26 F-box proteins in A. fumigatus and 30 F-box proteins in A. flavus are involved in SCF complex formation during vegetative growth. These interactome data also revealed that a diverse array of SCF complex conformations exist in response to various exogenous stressors. Lastly, we have provided evidence that the F-box protein Fbx45 interacts with SkpA in both species in response to Amphotericin B. Orthologs of the fbx45 gene are highly conserved in Aspergillus species, but are not present within the genomes of organisms such as yeast, plants or humans. This suggests that Fbx45 could potentially be a novel F-box protein that is unique to specific filamentous fungi such as Aspergillus species.
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Affiliation(s)
- Dean Frawley
- Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland.
| | - Özgür Bayram
- Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland.
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46
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Los A, Ziuzina D, Boehm D, Cullen PJ, Bourke P. Inactivation Efficacies and Mechanisms of Gas Plasma and Plasma-Activated Water against Aspergillus flavus Spores and Biofilms: a Comparative Study. Appl Environ Microbiol 2020; 86:e02619-19. [PMID: 32086309 PMCID: PMC7170485 DOI: 10.1128/aem.02619-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/12/2020] [Indexed: 01/24/2023] Open
Abstract
Atmospheric cold plasma (ACP) treatment is an emerging food technology for product safety and quality retention, shelf-life extension, and sustainable processing. The activated chemical species of ACP can act rapidly against microorganisms without leaving chemical residues on food surfaces. The main objectives of this study were to investigate the efficiency and mechanisms of inactivation of fungal spores and biofilms by ACP and to understand the effects of the gas-mediated and liquid-mediated modes of application against important fungal contaminants. Aspergillus flavus was selected as the model microorganism. A. flavus spores were exposed to either gas plasma (GP) or plasma-activated water (PAW), whereas gas plasma alone was used to treat A. flavus biofilms. This study demonstrated that both GP and PAW treatments independently resulted in significant decreases of A. flavus metabolic activity and spore counts, with maximal reductions of 2.2 and 0.6 log10 units for GP and PAW, respectively. The characterization of the reactive oxygen and nitrogen species in PAW and spore suspensions indicated that the concentration of secondary reactive species was an important factor influencing the antimicrobial activity of the treatment. The biofilm study showed that GP had detrimental effects on biofilm structure; however, the initial inoculum concentration prior to biofilm formation can be a crucial factor influencing the fungicidal effects of ACP.IMPORTANCE The production of mycotoxin-free food remains a challenge in both human and animal food chains. A. flavus, a mycotoxin-producing contaminant of economically important crops, was selected as the model microorganism to investigate the efficiency and mechanisms of ACP technology against fungal contaminants of food. Our study directly compares the antifungal properties of gas plasma (GP) and plasma-activated water (PAW) against fungi as well as reporting the effects of ACP treatment on biofilms produced by A. flavus.
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Affiliation(s)
- Agata Los
- Plasma Research Group, School of Food Science and Environmental Health, Technological University of Dublin, Dublin, Ireland
| | - Dana Ziuzina
- Plasma Research Group, School of Food Science and Environmental Health, Technological University of Dublin, Dublin, Ireland
| | - Daniela Boehm
- Plasma Research Group, School of Food Science and Environmental Health, Technological University of Dublin, Dublin, Ireland
| | - Patrick J Cullen
- Plasma Research Group, School of Food Science and Environmental Health, Technological University of Dublin, Dublin, Ireland
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
| | - Paula Bourke
- Plasma Research Group, School of Food Science and Environmental Health, Technological University of Dublin, Dublin, Ireland
- School of Biological Sciences, Institute for Global Food Security, Queens University Belfast, Belfast, United Kingdom
- Plasma Research Group, School of Biosystems and Food Engineering, University College Dublin, Belfield, Dublin, Ireland
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47
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Antagonistic Efficiency of Aspergillus giganteus as a Biocontrol Agent against Aflatoxigenic Aspergillus flavus Infecting Maize. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.1.55] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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48
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Tian F, Lee SY, Woo SY, Chun HS. Alternative Oxidase: A Potential Target for Controlling Aflatoxin Contamination and Propagation of Aspergillus flavus. Front Microbiol 2020; 11:419. [PMID: 32256475 PMCID: PMC7092633 DOI: 10.3389/fmicb.2020.00419] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/27/2020] [Indexed: 12/16/2022] Open
Abstract
Aflatoxins are among the most hazardous natural cereal contaminants. These mycotoxins are produced by Aspergillus spp. as polyketide secondary metabolites. Aflatoxigenic fungi including A. flavus express the alternative oxidase (AOX), which introduces a branch in the cytochrome-based electron transfer chain by coupling ubiquinol oxidation directly with the reduction of O2 to H2O. AOX is closely associated with fungal pathogenesis, morphogenesis, stress signaling, and drug resistance and, as recently reported, affects the production of mycotoxins such as sterigmatocystin, the penultimate intermediate in aflatoxin B1 biosynthesis. Thus, AOX might be considered a target for controlling the propagation of and aflatoxin contamination by A. flavus. Hence, this review summarizes the current understanding of fungal AOX and the alternative respiration pathway and the development and potential applications of AOX inhibitors. This review indicates that AOX inhibitors, either alone or in combination with current antifungal agents, are potentially applicable for developing novel, effective antifungal strategies. However, considering the conservation of AOX in fungal and plant cells, a deeper understanding of fungal alternative respiration and fungal AOX structure is needed, along with effective fungal-specific AOX inhibitors.
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Affiliation(s)
- Fei Tian
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Sang Yoo Lee
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - So Young Woo
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Hyang Sook Chun
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
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49
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Frawley D, Greco C, Oakley B, Alhussain MM, Fleming AB, Keller NP, Bayram Ö. The tetrameric pheromone module SteC-MkkB-MpkB-SteD regulates asexual sporulation, sclerotia formation and aflatoxin production in Aspergillus flavus. Cell Microbiol 2020; 22:e13192. [PMID: 32068947 PMCID: PMC7202998 DOI: 10.1111/cmi.13192] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/07/2020] [Accepted: 01/26/2020] [Indexed: 11/29/2022]
Abstract
For eukaryotes like fungi to regulate biological responses to environmental stimuli, various signalling cascades are utilized, like the highly conserved mitogen‐activated protein kinase (MAPK) pathways. In the model fungus Aspergillus nidulans, a MAPK pathway known as the pheromone module regulates development and the production of secondary metabolites (SMs). This pathway consists five proteins, the three kinases SteC, MkkB and MpkB, the adaptor SteD and the scaffold HamE. In this study, homologs of these five pheromone module proteins have been identified in the plant and human pathogenic fungus Aspergillus flavus. We have shown that a tetrameric complex consisting of the three kinases and the SteD adaptor is assembled in this species. It was observed that this complex assembles in the cytoplasm and that MpkB translocates into the nucleus. Deletion of steC, mkkB, mpkB or steD results in abolishment of both asexual sporulation and sclerotia production. This complex is required for the positive regulation of aflatoxin production and negative regulation of various SMs, including leporin B and cyclopiazonic acid (CPA), likely via MpkB interactions in the nucleus. These data highlight the conservation of the pheromone module in Aspergillus species, signifying the importance of this pathway in regulating fungal development and secondary metabolism.
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Affiliation(s)
- Dean Frawley
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Claudio Greco
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Berl Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Mohamed M Alhussain
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Alastair B Fleming
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Özgür Bayram
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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50
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Aflatoxin Biosynthesis and Genetic Regulation: A Review. Toxins (Basel) 2020; 12:toxins12030150. [PMID: 32121226 PMCID: PMC7150809 DOI: 10.3390/toxins12030150] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/27/2020] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.
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