151
|
Mukasa Y, Kyamanywa S, Sserumaga JP, Otim M, Tumuhaise V, Erbaugh M, Egonyu JP. An atoxigenic L-strain of Aspergillus flavus (Eurotiales: Trichocomaceae) is pathogenic to the coffee twig borer, Xylosandrus compactus (Coleoptera: Curculionidea: Scolytinae). ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:508-517. [PMID: 30307121 DOI: 10.1111/1758-2229.12705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/01/2018] [Accepted: 10/07/2018] [Indexed: 06/08/2023]
Abstract
This study isolated and evaluated virulence of fungal entomopathogens of Xylosandrus compactus - an important pest of Robusta coffee in Sub-Saharan Africa. A survey was conducted in five farming systems in Uganda to isolate entomopathogens associated with X. compactus. Four fungal isolates were screened for virulence against X. compactus in the laboratory at 1 × 107 conidia ml-1 where an atoxigenic L-strain of A. flavus killed 70%-100% of all stages of X. compactus compared with other unidentified isolates which caused 20%-70% mortalities. The time taken by A. flavus to kill 50% of X. compactus eggs, larvae, pupae and adults in the laboratory was 2-3 days; whereas the other unidentified fungal isolates took 4-7 days. The concentrations of A. flavus that killed 50% of different stages of X. compactus were 5 × 105 , 12 × 105 , 17 × 105 and 30 × 105 conidia ml-1 for larvae, eggs, pupae and adults respectively. A formulation of A. flavus in oil caused higher mortalities of X. compactus larvae, pupae and adults in the field (71%-79%) than its formulation in water (33%-47%). The atoxigenic strain of A. flavus could therefore be developed into a safe biopesticide against X. compactus.
Collapse
Affiliation(s)
- Yosia Mukasa
- Department of Agricultural Production, Makerere University, Kampala, Uganda
| | - Samuel Kyamanywa
- Department of Agricultural Production, Makerere University, Kampala, Uganda
| | - Julius P Sserumaga
- Department of Agriculture, National Crops Resources Research Institute, Kampala, Uganda
| | - Michael Otim
- Department of Agriculture, National Crops Resources Research Institute, Kampala, Uganda
| | | | - Mark Erbaugh
- College of Food, Agricultural, and Environmental Sciences, The Ohio State University, Columbus, OH, 43210, USA
| | - James P Egonyu
- Department of Agricultural Production, Makerere University, Kampala, Uganda
| |
Collapse
|
152
|
Han G, Zhao K, Yan X, Xiang F, Li X, Tao F. Differential regulation of mycelial growth and aflatoxin biosynthesis by Aspergillus flavus under different temperatures as revealed by strand-specific RNA-Seq. Microbiologyopen 2019; 8:e897. [PMID: 31328901 PMCID: PMC6813451 DOI: 10.1002/mbo3.897] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 11/11/2022] Open
Abstract
Although several regulatory pathways have been reported for Aspergillus flavus, the regulation of aflatoxin production and mycelial growth under different temperatures remains unclear. In this study, A. flavus differentially expressed genes (DEGs) and regulatory pathways were analyzed under three temperatures, by strand‐specific RNA‐Seq. Results show that a total of 2,428 and 1,474 DEGs were identified in fungal mycelia cultured at 20°C and 37°C, respectively, as compared with the control (28°C). Approximately ~ 79% of DEGs in the 37°C samples were up‐regulated genes, while ~ 63% of DEGs in the 20°C samples were down‐regulated genes. Most of the DEG pathways enriched by lower temperatures differed from those enriched by higher temperatures, while only a small portion of the pathways were shared by A. flavus grown under different temperatures. Aflatoxin biosynthesis, Butanoate metabolism, oxidation–reduction process, and benzene‐containing compound metabolic process were the shared down‐regulated pathways, while steroid biosynthesis, oxidoreductase activity, cellular protein modification process, DNA binding, protein complex were the shared up‐regulated pathways between lower and higher temperatures. The shared genes and pathways are the key regulatory candidates for aflatoxin biosynthesis with changes of temperature. In addition, the identification of both up‐regulated and down‐regulated genes provides a useful gene set for further investigation of the aflatoxin biosynthesis among Aspergillus.
Collapse
Affiliation(s)
- Guomin Han
- School of Life Sciences, Anhui Agricultural University, Hefei, China.,The National Engineering Laboratory of Crop Stress Resistance Breeding, Anhui Agricultural University, Hefei, China
| | - Kai Zhao
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Xiaodan Yan
- School of Management, Hefei University of Technology, Hefei, China
| | - Fangzhi Xiang
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Xuede Li
- School of Resources and Environment, Anhui Agricultural University, Hefei, China
| | - Fang Tao
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| |
Collapse
|
153
|
Bansal S, Mangal M, Tushir S, Oberoi HS, Gupta RK. A rapid and reliable method for the specific detection of aflatoxigenic fungi in groundnut and rice samples. J FOOD PROCESS PRES 2019. [DOI: 10.1111/jfpp.14127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Sangita Bansal
- ICAR‐Central Institute of Post‐Harvest Engineering & Technology Ludhiana India
| | - Manisha Mangal
- ICAR‐Indian Agriculture Research Institute New Delhi India
| | - Surya Tushir
- ICAR‐Central Institute of Post‐Harvest Engineering & Technology Ludhiana India
| | | | - Ram K. Gupta
- ICAR‐Central Institute of Post‐Harvest Engineering & Technology Ludhiana India
| |
Collapse
|
154
|
Wang P, Ma L, Jin J, Zheng M, Pan L, Zhao Y, Sun X, Liu Y, Xing F. The anti-aflatoxigenic mechanism of cinnamaldehyde in Aspergillus flavus. Sci Rep 2019; 9:10499. [PMID: 31324857 PMCID: PMC6642104 DOI: 10.1038/s41598-019-47003-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/09/2019] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin B1 (AFB1), the predominant and most carcinogenic naturally polyketide, is mainly produced by Aspergillus flavus and Aspergillus parasiticus. Cinnamaldehyde has been reported for inhibiting the growth and aflatoxin biosynthesis in A. flavus. But its molecular mechanism of action still remains largely ambiguous. Here, the anti-aflatoxigenic mechanism of cinnamaldehyde in A. flavus was investigated via a comparative transcriptomic analysis. The results indicated that twenty five of thirty genes in aflatoxin cluster showed down-regulation by cinnamaldehyde although the cluster regulators aflR and aflS were slightly up-regulated. This may be due to the up-regulation of the oxidative stress-related genes srrA, msnA and atfB being caused by the significant down-regulation of the diffusible factor FluG. Cinnamaldehyde also inhibited aflatoxin formation by perturbing GPCRs and oxylipins normal function, cell wall biosynthesis and redox equilibrium. In addition, accumulation of NADPH due to up-regulation of pentose phosphate pathway drove acetyl-CoA to lipids synthesis rather than polyketides. Both GO and KEGG analysis suggested that pyruvate and phenylalanine metabolism, post-transcriptional modification and key enzymes biosynthesis might be involved in the suppression of AFB1 production by cinnamaldehyde. This study served to decipher the anti-aflatoxigenic properties of cinnamaldehyde in A. flavus and provided powerful evidence for its use in practice.
Collapse
Affiliation(s)
- Ping Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Longxue Ma
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Jing Jin
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Mumin Zheng
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Lin Pan
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Yueju Zhao
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Xiulan Sun
- State Key Laboratory of Food Science and Technology, School of Food Science, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu, 214122, P.R. China
| | - Yang Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China
| | - Fuguo Xing
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, 100193, P.R. China.
| |
Collapse
|
155
|
Balogh K, Kövesi B, Zándoki E, Kulcsár S, Ancsin Z, Erdélyi M, Dobolyi C, Bata-Vidács I, Inotai K, Szekeres A, Mézes M, Kukolya J. Effect of Sterigmatocystin or Aflatoxin Contaminated Feed on Lipid Peroxidation and Glutathione Redox System and Expression of Glutathione Redox System Regulatory Genes in Broiler Chicken. Antioxidants (Basel) 2019; 8:E201. [PMID: 31261801 PMCID: PMC6680631 DOI: 10.3390/antiox8070201] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 06/17/2019] [Accepted: 06/26/2019] [Indexed: 12/02/2022] Open
Abstract
Authors studied the effect of sterigmatocystin from infected corn (STC), purified sterigmatocystin (PSTC), and aflatoxin B1 from infected corn (AFB1) on lipid peroxidation and glutathione redox parameters, including the expression of their encoding genes in a sub-chronic (14 days) trial. A total of 144 three-week-old cockerels was divided into four experimental groups (n = 36 in each). Control feed was contaminated with STC or PSTC (1590 µg STC/kg or 1570.5 µg STC/kg feed), or with AFB1 (149.1 µg AFB1/kg feed). Six birds from each group were sampled at day 1, 2, 3, 7 and 14 of mycotoxin exposure. As parameters of lipid peroxidation, conjugated dienes (CD) and trienes (CT) were measured in the liver, while malondialdehyde (MDA) concentration was determined in blood plasma, red blood cell hemolysate and liver. Reduced glutathione (GSH) concentration and glutathione peroxidase (GPx) activity were determined in the same samples, and expression of glutathione peroxidase 4 (GPX4), glutathione synthetase (GSS) and glutathione reductase (GSR) genes was measured by RT-PCR in the liver. STC, PSTC or AFB1 caused a slight, but not significant, increase in CD and CT levels; however, in the case of MDA, no increase was found in the liver. Glutathione redox system was activated in the liver by AFB1, but less markedly by STC/PSTC. PSTC and AFB1 resulted in a higher expression of GPX4, while GSS expression was down-regulated by AFB1 on day 1, but up-regulated by STC on day 2 and by both mycotoxins on day 7. However, on day 14, GSS expression was down-regulated by PSTC. Expression of GSR was low on day 1 in AFB1 and PSTC groups, but later it was up-regulated by AFB1. The observed changes regarding gene expression strengthen the hypothesis that the mild oxidative stress, caused by the applied STC doses, activates the glutathione redox system of broiler chickens.
Collapse
Affiliation(s)
- Krisztián Balogh
- Department of Nutrition, Szent István University, H-2100 Gödöllő, Hungary.
- Mycotoxins in the Food Chain" Research Group, Hungarian Academy of Sciences-Kaposvár University-Szent István University, H-7400 Kaposvár, Hungary.
| | - Benjámin Kövesi
- Department of Nutrition, Szent István University, H-2100 Gödöllő, Hungary.
| | - Erika Zándoki
- Mycotoxins in the Food Chain" Research Group, Hungarian Academy of Sciences-Kaposvár University-Szent István University, H-7400 Kaposvár, Hungary.
| | - Szabina Kulcsár
- Mycotoxins in the Food Chain" Research Group, Hungarian Academy of Sciences-Kaposvár University-Szent István University, H-7400 Kaposvár, Hungary.
| | - Zsolt Ancsin
- Department of Nutrition, Szent István University, H-2100 Gödöllő, Hungary.
| | - Márta Erdélyi
- Department of Nutrition, Szent István University, H-2100 Gödöllő, Hungary.
| | - Csaba Dobolyi
- Department of Environmental and Applied Microbiology, Agro-Environmental Research Institute, National Agricultural Research and Innovation Centre (NARIC) H-1022 Budapest, Hungary.
| | - Ildikó Bata-Vidács
- Department of Environmental and Applied Microbiology, Agro-Environmental Research Institute, National Agricultural Research and Innovation Centre (NARIC) H-1022 Budapest, Hungary.
| | - Katalin Inotai
- Department of Environmental and Applied Microbiology, Agro-Environmental Research Institute, National Agricultural Research and Innovation Centre (NARIC) H-1022 Budapest, Hungary.
| | - András Szekeres
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary.
| | - Miklós Mézes
- Department of Nutrition, Szent István University, H-2100 Gödöllő, Hungary.
- Mycotoxins in the Food Chain" Research Group, Hungarian Academy of Sciences-Kaposvár University-Szent István University, H-7400 Kaposvár, Hungary.
| | - József Kukolya
- Department of Environmental and Applied Microbiology, Agro-Environmental Research Institute, National Agricultural Research and Innovation Centre (NARIC) H-1022 Budapest, Hungary.
| |
Collapse
|
156
|
Shen L, Porée FH, Gaslonde T, Lalucque H, Chapeland-Leclerc F, Ruprich-Robert G. Functional characterization of the sterigmatocystin secondary metabolite gene cluster in the filamentous fungus Podospora anserina: involvement in oxidative stress response, sexual development, pigmentation and interspecific competitions. Environ Microbiol 2019; 21:3011-3026. [PMID: 31136075 DOI: 10.1111/1462-2920.14698] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/24/2019] [Accepted: 05/25/2019] [Indexed: 12/13/2022]
Abstract
Filamentous fungi are known as prolific untapped reservoirs of diverse secondary metabolites, where genes required for their synthesis are organized in clusters. The bioactive properties of these compounds are closely related to their functions in fungal biology, which are not well understood. In this study, we focused on the Podospora anserina gene cluster responsible for the biosynthesis of sterigmatocystin (ST). Deletion of the PaStcA gene encoding the polyketide synthase and overexpression (OE) of the PaAflR gene encoding the ST-specific transcription factor in P. anserina were performed. We showed that growth of PaStcAΔ was inhibited in the presence of methylglyoxal, while OE-PaAflR showed a little inhibition, indicating that ST production may enhance oxidative stress tolerance in P. anserina. We also showed that the OE-PaAflR strain displayed an overpigmented thallus mediated by the melanin pathway. Overexpression of PaAflR also led to sterility. Interspecific confrontation assays showed that ST-overexpressed strains produced a high level of peroxides and possessed a higher competitiveness against other fungi. Comparative metabolite profiling demonstrated that PaStcAΔ strain was unable to produce ST, while OE-PaAflR displayed a ST overproduction. This study contributes to a better understanding of ST in P. anserina, especially with regard to its involvement in fungal physiology.
Collapse
Affiliation(s)
- Ling Shen
- Laboratoire Interdisciplinaire des Energies de Demain (LIED), Université de Paris, Université Paris Diderot, UMR 8236, 75205, Paris, France
| | - François-Hugues Porée
- Laboratoire de Pharmacognosie, Faculté de Pharmacie de Paris, Université de Paris, Université Paris Descartes, UMR CNRS CITCOM 8038, 75006, Paris, France
| | - Thomas Gaslonde
- Laboratoire de Pharmacognosie, Faculté de Pharmacie de Paris, Université de Paris, Université Paris Descartes, UMR CNRS CITCOM 8038, 75006, Paris, France
| | - Hervé Lalucque
- Laboratoire Interdisciplinaire des Energies de Demain (LIED), Université de Paris, Université Paris Diderot, UMR 8236, 75205, Paris, France
| | - Florence Chapeland-Leclerc
- Laboratoire Interdisciplinaire des Energies de Demain (LIED), Université de Paris, Université Paris Descartes, UMR 8236, 75205, Paris, France
| | - Gwenaël Ruprich-Robert
- Laboratoire Interdisciplinaire des Energies de Demain (LIED), Université de Paris, Université Paris Descartes, UMR 8236, 75205, Paris, France
| |
Collapse
|
157
|
Hua SST, Parfitt DE, Sarreal SBL, Sidhu G. Dual culture of atoxigenic and toxigenic strains of Aspergillus flavus to gain insight into repression of aflatoxin biosynthesis and fungal interaction. Mycotoxin Res 2019; 35:381-389. [PMID: 31161589 DOI: 10.1007/s12550-019-00364-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 03/27/2019] [Accepted: 05/06/2019] [Indexed: 11/24/2022]
Abstract
Application of atoxigenic strains to compete against toxigenic strains of Aspergillus flavus strains has emerged as one of the practical strategies for reducing aflatoxin contamination in corn, peanut, and tree nuts. The actual mechanism that results in aflatoxin reduction is not fully understood. Real-time RT-PCR and relative quantification of gene expression protocol were applied to elucidate the molecular mechanism. Transcriptional analyses of aflatoxin biosynthetic gene cluster in dual culture of toxigenic and atoxigenic A. flavus strains were carried out. Six targeted genes, aflR, aflJ, omtA, ordA, pksA, and vbs, were downregulated to variable levels depending on paired strains of toxigenic and atoxigenic A. flavus. Consistent with the decreased gene expression levels, the aflatoxin concentrations in dual cultures were reduced significantly in comparison with toxigenic cultures. Fluorescent images showed fungal hyphae in dual culture displayed green fluorescent, and contacts of live hyphae were seen. A coconut agar plate assay was used to show that toxigenic A. flavus colony produced blue fluorescence under long UV exposure, suggesting that aflatoxin is exported outside fungal hyphae. Furthermore, the assay was applied to demonstrate the potential role of thigmo-regulation in fungal interaction.
Collapse
Affiliation(s)
- Sui Sheng T Hua
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA, 94710, USA.
| | - Dan E Parfitt
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Siov Bouy L Sarreal
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA, 94710, USA
| | - Gaganjot Sidhu
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA, 94710, USA
| |
Collapse
|
158
|
Elzaki MEA, Xue RR, Hu L, Wang JD, Zeng RS, Song YY. Bioactivation of aflatoxin B1 by a cytochrome P450, CYP6AE19 induced by plant signaling methyl jasmonate in Helicoverpa armigra (Hübner). PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 157:211-218. [PMID: 31153471 DOI: 10.1016/j.pestbp.2019.03.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/20/2019] [Accepted: 03/31/2019] [Indexed: 06/09/2023]
Abstract
Herbivore attack leads to enhanced production of defensive compounds to mount anti-herbivore defense in plants via activation of the jasmonate signaling pathway. On the other hand, some herbivores can eavesdrop on plants defense signaling and up-regulate their cytochrome P450 genes to increase detoxification of defensive compounds. However, the ecological risk of eavesdropping on plant defense signaling is largely unknown. In this study, we examined the induction of cytochrome P450s by methyl jasmonate (MeJA) and its consequence on the toxicity of aflatoxin B1 (AFB1) to Helicoverpa armigra larvae. The results show that MeJA applications either in a diet or volatile exposure enhanced the toxicity of AFB1 to the larvae. RNA sequences analysis revealed that cytochrome P450 CYP6AE19 was highly induced when MeJA was applied with AFB1. In addition, HaGST encoding glutathione-S-transferase that mainly transforms aflatoxin B1 exo-8,9-epoxide to aflatoxin B1 exo-8,9-glutathione was also induced. RNA interference of CYP6AE19 via injecting a double-stranded RNA decreased mortality of larvae exposed to AFB1; while injecting a double-stranded RNA of HaGST increased larval mortality. Furthermore, a protein model was generated and a subsequent docking simulation for AFB1 suggests the bioactivation as a major mechanism of AFB1. This study provides evidence that MeJA increased larval mortality of H. armigera via induction of CYP6AE19 that can bioactivate AFB1.
Collapse
Affiliation(s)
- Mohammed Esmail Abdalla Elzaki
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Rong-Rong Xue
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lin Hu
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jin-da Wang
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ren-Sen Zeng
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuan-Yuan Song
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| |
Collapse
|
159
|
Preparation, characterization and anti-aflatoxigenic activity of chitosan packaging films incorporated with turmeric essential oil. Int J Biol Macromol 2019; 131:420-434. [DOI: 10.1016/j.ijbiomac.2019.02.169] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 11/18/2022]
|
160
|
Kujur A, Yadav A, Kumar A, Singh PP, Prakash B. Nanoencapsulated methyl salicylate as a biorational alternative of synthetic antifungal and aflatoxin B 1 suppressive agents. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:18440-18450. [PMID: 31049858 DOI: 10.1007/s11356-019-05171-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
In view of the suspected negative impact of synthetic fungicides to the human health, nutritional quality, and non-targeted organisms, the use of plant-based antifungal agents has gained considerable interest to the agri-food industries. The aim of this study was to explore the antifungal and aflatoxin B1 (AFB1) inhibitory activity of chitosan (low molecular weight) encapsulated methyl salicylate. The nanoencapsulation of methyl salicylate (Ne-MS) has been characterized by SEM, FTIR, and XRD analysis. The encapsulation efficiency and loading capacity of Ne-MS ranged between 32-34% and 5-7% respectively. The minimum inhibitory concentration of Ne-MS (1.00 μL/mL) against the growth and aflatoxin B1 production by Aspergillus flavus was found to be lower than the free MS (1.50 μL/mL). Mode of action studies demonstrated that the Ne-MS cause a significant decrease in the ergosterol content, leakage of vital ions (Ca2+, Mg2+, and K+), utilization of different carbon source by the A. flavus. Further, the docking result showed ver1 and omt A gene of AFB1 biosynthesis are the possible molecular site of action of methyl salicylate. The in situ study revealed that Ne-MS had no significant negative impact on the organoleptic properties of the food system (maize) which strengthen its potential as a biorational alternative of synthetic fungicides.
Collapse
Affiliation(s)
- Anupam Kujur
- Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Amrita Yadav
- Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Akshay Kumar
- Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Prem Pratap Singh
- Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Bhanu Prakash
- Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
| |
Collapse
|
161
|
Genetic regulation of aflatoxin, ochratoxin A, trichothecene, and fumonisin biosynthesis: A review. Int Microbiol 2019; 23:89-96. [DOI: 10.1007/s10123-019-00084-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 01/09/2023]
|
162
|
Functional Analysis of Peptidyl-prolyl cis-trans Isomerase from Aspergillus flavus. Int J Mol Sci 2019; 20:ijms20092206. [PMID: 31060313 PMCID: PMC6539592 DOI: 10.3390/ijms20092206] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 04/29/2019] [Accepted: 05/02/2019] [Indexed: 02/07/2023] Open
Abstract
Aspergillus flavus, a ubiquitous filamentous fungus found in soil, plants and other substrates has been reported not only as a pathogen for plants, but also a carcinogen producing fungus for human. Peptidyl-Prolyl Isomerase (PPIases) plays an important role in cell process such as protein secretion cell cycle control and RNA processing. However, the function of PPIase has not yet been identified in A. flavus. In this study, the PPIases gene from A. flavus named ppci1 was cloned into expression vector and the protein was expressed in prokaryotic expression system. Activity of recombinant ppci1 protein was particularly inhibited by FK506, CsA and rapamycin. 3D-Homology model of ppci1 has been constructed with the template, based on 59.7% amino acid similarity. The homologous recombination method was used to construct the single ppci1 gene deletion strain Δppci1. We found that, the ppci1 gene plays important roles in A. flavus growth, conidiation, and sclerotia formation, all of which showed reduction in Δppci1 and increased in conidiation compared with the wild-type and complementary strains in A. flavus. Furthermore, aflatoxin and peanut seeds infection assays indicated that ppci1 contributes to virulence of A. flavus. Furthermore, we evaluated the effect of PPIase inhibitors on A. flavus growth, whereby these were used to treat wild-type strains. We found that the growths were inhibited under every inhibitor. All, these results may provide valuable information for designing inhibitors in the controlling infections of A. flavus.
Collapse
|
163
|
Devi MS, Sashidhar RB. Antiaflatoxigenic effects of selected antifungal peptides. Peptides 2019; 115:15-26. [PMID: 30776385 DOI: 10.1016/j.peptides.2019.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 12/11/2022]
Abstract
Aflatoxins are potent carcinogenic mycotoxins produced as secondary metabolites mainly by the fungi Aspergillus flavus and Aspergillus parasiticus. Control measures to curtail the contamination of aflatoxin in food products is still a challenge. Although there are several reports on the antifungal peptides, there is no specific study on the action of antifungal peptides on aflatoxin synthesis. This work details the effect of four antimicrobial peptides (AMPs) - PPD1 (FRLHF), 66-10 (FRLKFH), 77-3 (FRLKFHF) and D4E1 (FKLRAKIKVRLRAKIKL) on the aflatoxin production by A. flavus and A. parasiticus. Results of the investigations suggests that AMPs at near minimum inhibitory concentrations (MIC) were effectively inhibiting aflatoxins, without hindering the growth of the fungi. These AMPs, at concentrations near MIC, induced membrane permeabilisation, without inducing cellular leakage. The involvement of oxidative stress for the aflatoxin synthesis was reversed by the antioxidant nature of the peptides as evidenced by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay, reactive oxygen species production, malondialdehyde and antioxidant enzymes analysis. Quantitative real time polymerase chain reaction (RT-qPCR) analysis of the aflatoxin gene cluster showed that 'aflR' and its downstream genes expressions were significantly down regulated. Conidiation of the fungi were negatively influenced by the peptides as evidenced by scanning electron microscopy analysis and RT-qPCR. mRNA levels of Manganese-superoxide dismutase (Mn-SOD) showed a decrease in the expression in RT-qPCR. The effect of these peptides on aflatoxin inhibition provides insight into their use as novel antiaflatoxigenic molecules.
Collapse
Affiliation(s)
- Manju S Devi
- Department of Biochemistry, University College of Science, Osmania University, Hyderabad-500 007, Telangana State, India
| | - R B Sashidhar
- Department of Biochemistry, University College of Science, Osmania University, Hyderabad-500 007, Telangana State, India.
| |
Collapse
|
164
|
Ortega-Beltran A, Moral J, Picot A, Puckett RD, Cotty PJ, Michailides TJ. Atoxigenic Aspergillus flavus Isolates Endemic to Almond, Fig, and Pistachio Orchards in California with Potential to Reduce Aflatoxin Contamination in these Crops. PLANT DISEASE 2019; 103:905-912. [PMID: 30807246 DOI: 10.1094/pdis-08-18-1333-re] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In California, aflatoxin contamination of almond, fig, and pistachio has become a serious problem in recent years due to long periods of drought and probably other climatic changes. The atoxigenic biocontrol product Aspergillus flavus AF36 has been registered for use to limit aflatoxin contamination of pistachio since 2012 and for use in almond and fig since 2017. New biocontrol technologies employ multiple atoxigenic genotypes because those provide greater benefits than using a single genotype. Almond, fig, and pistachio industries would benefit from a multi-strain biocontrol technology for use in these three crops. Several A. flavus vegetative compatibility groups (VCGs) associated with almond, fig, and pistachio composed exclusively of atoxigenic isolates, including the VCG to which AF36 belongs to, YV36, were previously characterized in California. Here, we report additional VCGs associated with either two or all three crops. Representative isolates of 12 atoxigenic VCGs significantly (P < 0.001) reduced (>80%) aflatoxin accumulation in almond and pistachio when challenged with highly toxigenic isolates of A. flavus and A. parasiticus under laboratory conditions. Isolates of the evaluated VCGs, including AF36, constitute valuable endemic, well-adapted, and efficient germplasm to design a multi-crop, multi-strain biocontrol strategy for use in tree crops in California. Availability of such a strategy would favor long-term atoxigenic A. flavus communities across the affected areas of California, and this would result in securing domestic and export markets for the nut crop and fig farmer industries and, most importantly, health benefits to consumers.
Collapse
Affiliation(s)
- Alejandro Ortega-Beltran
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Juan Moral
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Adeline Picot
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Ryan D Puckett
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Peter J Cotty
- 2 United States Department of Agriculture-Agricultural Research Service, School of Plant Sciences, The University of Arizona, Tucson, AZ 85721
| | - Themis J Michailides
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| |
Collapse
|
165
|
Pires PN, Vargas EA, Gomes MB, Vieira CBM, Santos EAD, Bicalho AAC, Silva SDC, Rezende RP, Oliveira ISD, Luz EDMN, Trovatti Uetanabaro AP. Aflatoxins and ochratoxin A: occurrence and contamination levels in cocoa beans from Brazil. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2019; 36:815-824. [DOI: 10.1080/19440049.2019.1600749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Polyane Novais Pires
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz (UESC), Campus Soane Nazaré de Andrade, Ilhéus, Bahia, Brazil
| | - Eugênia Azevedo Vargas
- Laboratório de Controle de Qualidade e Segurança Alimentar (LACQSA), Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Belo Horizonte, Minas Gerais, Brazil
| | - Mateus Batista Gomes
- Laboratório de Controle de Qualidade e Segurança Alimentar (LACQSA), Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Belo Horizonte, Minas Gerais, Brazil
| | - Caroline Brasil Melo Vieira
- Laboratório de Controle de Qualidade e Segurança Alimentar (LACQSA), Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Belo Horizonte, Minas Gerais, Brazil
| | - Eliene Alves dos Santos
- Laboratório de Controle de Qualidade e Segurança Alimentar (LACQSA), Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Belo Horizonte, Minas Gerais, Brazil
| | - Ana Angélica Cangussu Bicalho
- Laboratório de Controle de Qualidade e Segurança Alimentar (LACQSA), Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Belo Horizonte, Minas Gerais, Brazil
| | | | - Rachel Passos Rezende
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz (UESC), Campus Soane Nazaré de Andrade, Ilhéus, Bahia, Brazil
| | - Idjane Santana De Oliveira
- Centro Acadêmico de Vitória – CAV, Universidade Federal de Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - Edna Dora Martins Newman Luz
- Centro de Pesquisa do Cacau - CEPEC, Setor de Fitopatologia, Comissão Executiva do Plano da Lavoura Cacaueira (CEPLAC), Ilhéus, Bahia, Brazil
| | - Ana Paula Trovatti Uetanabaro
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz (UESC), Campus Soane Nazaré de Andrade, Ilhéus, Bahia, Brazil
| |
Collapse
|
166
|
Uka V, Moore GG, Arroyo-Manzanares N, Nebija D, De Saeger S, Diana Di Mavungu J. Secondary Metabolite Dereplication and Phylogenetic Analysis Identify Various Emerging Mycotoxins and Reveal the High Intra-Species Diversity in Aspergillus flavus. Front Microbiol 2019; 10:667. [PMID: 31024476 PMCID: PMC6461017 DOI: 10.3389/fmicb.2019.00667] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/18/2019] [Indexed: 12/18/2022] Open
Abstract
Aspergillus flavus is one of the most important mycotoxigenic species from the genus Aspergillus, due to its ability to synthesize the potent hepatocarcinogen, aflatoxin B1. Moreover, this fungus is capable of producing several other toxic metabolites from the class of indole-tetramates, non-ribosomal peptides, and indole-diterpenoids. Populations of A. flavus are characterized by considerable diversity in terms of morphological, functional and genetic features. Although for many years A. flavus was considered an asexual fungus, researchers have shown evidence that at best these fungi can exhibit a predominantly asexual existence. We now know that A. flavus contains functional genes for mating, uncovering sexuality as potential contributor for its diversification. Based on our results, we reconfirm that A. flavus is a predominant producer of B-type aflatoxins. Moreover, this fungus can decisively produce AFM1 and AFM2. We did not observe any clear relationship between mating-type genes and particular class of metabolites, probably other parameters such as sexual/asexual ratio should be investigated. A dynamic secondary metabolism was found also in strains intended to be used as biocontrol agents. In addition we succeeded to provide mass spectrometry fragmentation spectra for the most important classes of A. flavus metabolites, which will serve as identification cards for future studies. Both, metabolic and phylogenetic analysis proved a high intra-species diversity for A. flavus. These findings contribute to our understanding about the diversity of Aspergillus section Flavi species, raising the necessity for polyphasic approaches (morphological, metabolic, genetic, etc.) when dealing with this type of complex group of species.
Collapse
Affiliation(s)
- Valdet Uka
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.,Department of Pharmacy, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo†
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, LA, United States
| | - Natalia Arroyo-Manzanares
- Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare-Nostrum", University of Murcia, Murcia, Spain
| | - Dashnor Nebija
- Department of Pharmacy, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo†
| | - 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
| |
Collapse
|
167
|
Kövesi B, Pelyhe C, Zándoki E, Mézes M, Balogh K. Effect of short-term sterigmatocystin exposure on lipid peroxidation and glutathione redox system and expression of glutathione redox system regulatory genes in common carp liver. Toxicon 2019; 161:50-56. [DOI: 10.1016/j.toxicon.2019.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 02/26/2019] [Accepted: 03/03/2019] [Indexed: 11/29/2022]
|
168
|
Lan H, Wu L, Fan K, Sun R, Yang G, Zhang F, Yang K, Lin X, Chen Y, Tian J, Wang S. Set3 Is Required for Asexual Development, Aflatoxin Biosynthesis, and Fungal Virulence in Aspergillus flavus. Front Microbiol 2019; 10:530. [PMID: 31001207 PMCID: PMC6455067 DOI: 10.3389/fmicb.2019.00530] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/01/2019] [Indexed: 12/30/2022] Open
Abstract
Aspergillus flavus is an opportunistic pathogenic fungus for both plant and animal that produces carcinogenic toxins termed aflatoxins (AFs). To identify possible genetic targets to reduce AF contamination, in this study, we have characterized a novel A. flavus Set3, and it shares sequence homology with the yeast protein Set3. The set3 deletion mutants present no difference in growth rate but alterations in asexual development and secondary metabolite production when compared to the A. flavus wild type. Specifically, deletion of set3 gene decreases conidiophore formation and conidial production through downregulating expression of brlA and abaA genes. In addition, normal levels of set3 are required for sclerotial development and expression of sclerotia-related genes nsdC and sclR. Further analyses demonstrated that Set3 negatively regulates AF production as well as the concomitant expression of genes in the AF gene cluster. Importantly, our results also display that A. flavus Set3 is involved in crop kernel colonization. Taking together, these results reveal that a novel Set3 plays crucial roles in morphological development, secondary metabolism, and fungal virulence in A. flavus.
Collapse
Affiliation(s)
- Huahui Lan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lianghuan Wu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kun Fan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ruilin Sun
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guang Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kunlong Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,College of Life Science, Jiangsu Normal University, Xuzhou, China
| | - Xiaolu Lin
- Longyan City Corporation of Fujian Tobacco Corporation, Longyan, China
| | - Yanhong Chen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jun Tian
- College of Life Science, Jiangsu Normal University, Xuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| |
Collapse
|
169
|
Li B, Chen Y, Zong Y, Shang Y, Zhang Z, Xu X, Wang X, Long M, Tian S. Dissection of patulin biosynthesis, spatial control and regulation mechanism in Penicillium expansum. Environ Microbiol 2019; 21:1124-1139. [PMID: 30680886 DOI: 10.1111/1462-2920.14542] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/20/2019] [Accepted: 01/22/2019] [Indexed: 01/17/2023]
Abstract
The patulin biosynthesis is one of model pathways in an understanding of secondary metabolite biology and network novelties in fungi. However, molecular regulation mechanism of patulin biosynthesis and contribution of each gene related to the different catalytic enzymes in the biochemical steps of the pathway remain largely unknown in fungi. In this study, the genetic components of patulin biosynthetic pathway were systematically dissected in Penicillium expansum, which is an important fungal pathogen and patulin producer in harvested fruits and vegetables. Our results revealed that all the 15 genes in the cluster are involved in patulin biosynthesis. Proteins encoded by those genes are compartmentalized in various subcellular locations, including cytosol, nucleus, vacuole, endoplasmic reticulum, plasma membrane and cell wall. The subcellular localizations of some proteins, such as PatE and PatH, are required for the patulin production. Further, the functions of eight enzymes in the 10-step patulin biosynthetic pathway were verified in P. expansum. Moreover, velvet family proteins, VeA, VelB and VelC, were proved to be involved in the regulation of patulin biosynthesis, but not VosA. These findings provide a thorough understanding of the biosynthesis pathway, spatial control and regulation mechanism of patulin in fungi.
Collapse
Affiliation(s)
- Boqiang Li
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yong Chen
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanyuan Zong
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yanjiao Shang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhanquan Zhang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaodi Xu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Wang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois 60637, USA
| | - Shiping Tian
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China.,Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian 116600, China
| |
Collapse
|
170
|
Santos-Ciscon BAD, van Diepeningen A, Machado JDC, Dias IE, Waalwijk C. Aspergillus species from Brazilian dry beans and their toxigenic potential. Int J Food Microbiol 2019; 292:91-100. [DOI: 10.1016/j.ijfoodmicro.2018.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 11/27/2018] [Accepted: 12/06/2018] [Indexed: 10/27/2022]
|
171
|
Abstract
One of the exciting movements in microbial sciences has been a refocusing and revitalization of efforts to mine the fungal secondary metabolome. The magnitude of biosynthetic gene clusters (BGCs) in a single filamentous fungal genome combined with the historic number of sequenced genomes suggests that the secondary metabolite wealth of filamentous fungi is largely untapped. Mining algorithms and scalable expression platforms have greatly expanded access to the chemical repertoire of fungal-derived secondary metabolites. In this Review, I discuss new insights into the transcriptional and epigenetic regulation of BGCs and the ecological roles of fungal secondary metabolites in warfare, defence and development. I also explore avenues for the identification of new fungal metabolites and the challenges in harvesting fungal-derived secondary metabolites.
Collapse
|
172
|
Yuan J, Li D, Qin L, Shen J, Guo X, Tumukunde E, Li M, Wang S. HexA is required for growth, aflatoxin biosynthesis and virulence in Aspergillus flavus. BMC Mol Biol 2019; 20:4. [PMID: 30744561 PMCID: PMC6371581 DOI: 10.1186/s12867-019-0121-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 01/31/2019] [Indexed: 11/17/2022] Open
Abstract
Background Woronin bodies are fungal-specific organelles whose formation is derived from peroxisomes. The former are believed to be involved in the regulation of mycotoxins biosynthesis, but not in their damage repair function. The hexagonal peroxisome protein (HexA or Hex1) encoded by hexA gene in Aspergillus is the main and the essential component of the Woronin body. However, little is known about HexA in Aspergillus flavus. Results In this study, hexA knock-out mutant (ΔhexA) and complementation strain (ΔhexAC) were produced using homologous recombination. The results showed that, ΔhexA and ΔhexAC were successfully constructed. And the data analysis indicated that the colony diameter, stress sensitivity and the sclerotia formation of A. flavus were nearly not affected by the absence of HexA. Yet, the deletion of hexA gene reduced the production of asexual spores and lessened virulence on peanuts and maize seeds markedly. In addition, it was also found that there was a significant decrease of Aflatoxin B1 production in deletion mutant, when compared to wild type. Conclusions Therefore, it suggested that the hexA gene has an essential function in conidia production and secondary metabolism in A. flavus. The gene is also believed to be playing an important role in the invasion of A. flavus to the host.
Collapse
Affiliation(s)
- Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and 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, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ling Qin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jiaojiao Shen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiaodong Guo
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and 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, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mingzhu Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and 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, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| |
Collapse
|
173
|
Olarte RA, Menke J, Zhang Y, Sullivan S, Slot JC, Huang Y, Badalamenti JP, Quandt AC, Spatafora JW, Bushley KE. Chromosome rearrangements shape the diversification of secondary metabolism in the cyclosporin producing fungus Tolypocladium inflatum. BMC Genomics 2019; 20:120. [PMID: 30732559 PMCID: PMC6367777 DOI: 10.1186/s12864-018-5399-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/19/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Genes involved in production of secondary metabolites (SMs) in fungi are exceptionally diverse. Even strains of the same species may exhibit differences in metabolite production, a finding that has important implications for drug discovery. Unlike in other eukaryotes, genes producing SMs are often clustered and co-expressed in fungal genomes, but the genetic mechanisms involved in the creation and maintenance of these secondary metabolite biosynthetic gene clusters (SMBGCs) remains poorly understood. RESULTS In order to address the role of genome architecture and chromosome scale structural variation in generating diversity of SMBGCs, we generated chromosome scale assemblies of six geographically diverse isolates of the insect pathogenic fungus Tolypocladium inflatum, producer of the multi-billion dollar lifesaving immunosuppressant drug cyclosporin, and utilized a Hi-C chromosome conformation capture approach to address the role of genome architecture and structural variation in generating intraspecific diversity in SMBGCs. Our results demonstrate that the exchange of DNA between heterologous chromosomes plays an important role in generating novelty in SMBGCs in fungi. In particular, we demonstrate movement of a polyketide synthase (PKS) and several adjacent genes by translocation to a new chromosome and genomic context, potentially generating a novel PKS cluster. We also provide evidence for inter-chromosomal recombination between nonribosomal peptide synthetases located within subtelomeres and uncover a polymorphic cluster present in only two strains that is closely related to the cluster responsible for biosynthesis of the mycotoxin aflatoxin (AF), a highly carcinogenic compound that is a major public health concern worldwide. In contrast, the cyclosporin cluster, located internally on chromosomes, was conserved across strains, suggesting selective maintenance of this important virulence factor for infection of insects. CONCLUSIONS This research places the evolution of SMBGCs within the context of whole genome evolution and suggests a role for recombination between chromosomes in generating novel SMBGCs in the medicinal fungus Tolypocladium inflatum.
Collapse
Affiliation(s)
- Rodrigo A. Olarte
- 0000000419368657grid.17635.36Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN USA
| | - Jon Menke
- 0000 0001 0703 5300grid.450240.7Cargill Inc., Wayzata, MN USA
| | - Ying Zhang
- 0000000419368657grid.17635.36Minnesota Supercomputing Institute, Minneapolis, MN USA
| | | | - Jason C. Slot
- 0000 0001 2285 7943grid.261331.4Department of Plant Pathology, Ohio State University, Columbus, OH USA
| | - Yinyin Huang
- 0000000419368657grid.17635.36Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN USA
| | - Jonathan P. Badalamenti
- 0000000419368657grid.17635.36University of Minnesota Genomics Center, University of Minnesota, Minneapolis, MN USA
| | - Alisha C. Quandt
- 0000000096214564grid.266190.aDepartment of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO USA
| | - Joseph W. Spatafora
- 0000 0001 2112 1969grid.4391.fDepartment of Botany and Plant Pathology, Oregon State University, Corvallis, OR USA
| | - Kathryn E. Bushley
- 0000000419368657grid.17635.36Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN USA
| |
Collapse
|
174
|
Hua SST, Sarreal SBL, Chang PK, Yu J. Transcriptional Regulation of Aflatoxin Biosynthesis and Conidiation in Aspergillus flavus by Wickerhamomyces anomalus WRL-076 for Reduction of Aflatoxin Contamination. Toxins (Basel) 2019; 11:toxins11020081. [PMID: 30717146 PMCID: PMC6410245 DOI: 10.3390/toxins11020081] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/12/2018] [Accepted: 01/08/2019] [Indexed: 12/22/2022] Open
Abstract
Aspergillus flavus is a ubiquitous saprophytic fungus found in soils across the world. The fungus is the major producer of aflatoxin (AF) B₁, which is toxic and a potent carcinogen to humans. Aflatoxin B₁ (AFB₁) is often detected in agricultural crops such as corn, peanut, almond, and pistachio. It is a serious and recurrent problem and causes substantial economic losses. Wickerhamomyces anomalus WRL-076 was identified as an effective biocontrol yeast against A. flavus. In this study, the associated molecular mechanisms of biocontrol were investigated. We found that the expression levels of eight genes, aflR, aflJ, norA, omtA, omtB, pksA, vbs, and ver-1 in the aflatoxin biosynthetic pathway cluster were suppressed. The decreases ranged from several to 10,000 fold in fungal samples co-cultured with W. anomalus. Expression levels of conidiation regulatory genes brlA, abaA, and wetA as well as sclerotial regulatory gene (sclR) were all down regulated. Consistent with the decreased gene expression levels, aflatoxin concentrations in cultural medium were reduced to barely detectable. Furthermore, fungal biomass and conidial number were significantly reduced by 60% and more than 95%, respectively. The results validate the biocontrol efficacy of W. anomalus WRL-076 observed in the field experiments.
Collapse
Affiliation(s)
- Sui Sheng T Hua
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.
| | - Siov Bouy L Sarreal
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.
| | - Perng-Kuang Chang
- U.S. Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, 1100 Robert E. Boulevard, New Orleans, LA 70124, USA.
| | - Jiujiang Yu
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Center, Beltsville, MD 70124, USA.
| |
Collapse
|
175
|
Jiang MP, Zheng SY, Wang H, Zhang SY, Yao DS, Xie CF, Liu DL. Predictive model of aflatoxin contamination risk associated with granary-stored corn with versicolorin A monitoring and logistic regression. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2019; 36:308-319. [DOI: 10.1080/19440049.2018.1562226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Meng Ping Jiang
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
| | - Shao Yan Zheng
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
| | - Hao Wang
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
| | - Shu Yao Zhang
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China
| | - Dong Sheng Yao
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
- National Engineering Research Centre of Genetic Medicine, Jinan University, Guangzhou, China
| | - Chun Fang Xie
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
- National Engineering Research Centre of Genetic Medicine, Jinan University, Guangzhou, China
| | - Da Ling Liu
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, China
- Institute of Microbial Biotechnology, Jinan University, Guangzhou, China
| |
Collapse
|
176
|
Tumukunde E, Li D, Qin L, Li Y, Shen J, Wang S, Yuan J. Osmotic-Adaptation Response of sakA/hogA Gene to Aflatoxin Biosynthesis, Morphology Development and Pathogenicity in Aspergillus flavus. Toxins (Basel) 2019; 11:toxins11010041. [PMID: 30646608 PMCID: PMC6356625 DOI: 10.3390/toxins11010041] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 12/19/2018] [Accepted: 01/11/2019] [Indexed: 02/06/2023] Open
Abstract
Aspergillus flavus is one of the fungi from the big family of Aspergillus genus and it is capable of colonizing a large number of seed/crops and living organisms such as animals and human beings. SakA (also called hogA/hog1) is an integral part of the mitogen activated protein kinase signal of the high osmolarity glycerol pathway. In this study, the AfsakA gene was deleted (∆AfsakA) then complemented (∆AfsakA::AfsakA) using homologous recombination and the osmotic stress was induced by 1.2 mol/L D-sorbital and 1.2 mol/L sodium chloride. The result showed that ∆AfsakA mutant caused a significant influence on conidial formation compared to wild-type and ∆AfsakA::AfsakA strains. It was also found that AfsakA responds to both the osmotic stress and the cell wall stress. In the absence of osmotic stress, ∆AfsakA mutant produced more sclerotia in contrast to other strains, whereas all strains failed to generate sclerotia under osmotic stress. Furthermore, the deletion of AfsakA resulted in the increase of Aflatoxin B1 production compared to other strains. The virulence assay on both maize kernel and peanut seeds showed that ∆AfsakA strain drastically produced more conidia and Aflatoxin B1 than wild-type and complementary strains. AfSakA-mCherry was located to the cytoplasm in the absence of osmotic stress, while it translocated to the nucleus upon exposure to the osmotic stimuli. This study provides new insights on the development and evaluation of aflatoxin biosynthesis and also provides better understanding on how to prevent Aspergillus infections which would be considered the first step towards the prevention of the seeds damages caused by A. flavus.
Collapse
Affiliation(s)
- Elisabeth Tumukunde
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Ministry of Education and 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 the Ministry of Education and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Ling Qin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Ministry of Education and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Yu Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Ministry of Education and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Jiaojiao Shen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Ministry of Education and 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 the Ministry of Education and 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 the Ministry of Education and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| |
Collapse
|
177
|
Gomaa EZ, Abdelall MF, El-Mahdy OM. Detoxification of Aflatoxin B1 by Antifungal Compounds from Lactobacillus brevis and Lactobacillus paracasei, Isolated from Dairy Products. Probiotics Antimicrob Proteins 2019; 10:201-209. [PMID: 29150754 DOI: 10.1007/s12602-017-9350-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Aflatoxins are a large group of highly toxic, mutagenic, and carcinogenic mycotoxins produced by specific species of fungi. Potential contamination of food commodities by these compounds causes extensive damage that lead to great economic losses. This study explored the potential use of antifungal compounds, produced by Lactobacillus brevis and Lactobacillus paracasei, for growth inhibition and subsequent aflatoxin B1 production from select strains of Aspergillus flavus and Aspergillus parasiticus. Lactobacilli strains were isolated from traditional Egyptian dairy products, whereas fungal strains were isolated from infected cereal seeds. There were noticeable decreases in mycelium biomass and aflatoxin production as well. L. brevis exhibited the highest reduction of aflatoxin B1 production by A. flavus and A. parasiticus, 96.31 and 90.43%, respectively. The concentrations of amino acids of the antifungal compound produced by L. brevis were significantly higher than that produced by L. paracasei. Asparagine, glutamine, glycine, alanine, and leucine were the most concentrated amino acids for both strains. The antifungal compounds produced by L. brevis and L. paracasei were active in a wide range of pH, heat stable and inactivated by proteolytic enzymes (protease K and trypsin A). The expression of Omt-A gene that involved in the later step of aflatoxin production was evaluated by real-time PCR. There was a vigorous reduction at transcriptional level of Omt-A gene observed in A. flavus that is treated by L. brevis and L. paracasei (80 and 70%, respectively). However, the reduction of Omt-A gene observed in A. parasiticus that is treated by L. brevis and L. paracasei was 64.5 and 52%, respectively. Treating maize seeds with antifungal compounds exhibited great efficiency in controlling fungal infection and increasing seed germination. The results confirmed that lactic acid bacteria are a promising strategy to control food contamination of fermented food and dairy products.
Collapse
Affiliation(s)
- Eman Zakaria Gomaa
- Department of Biological and Geological Sciences, Faculty of Education, Ain Shams University, Cairo, Egypt.
| | - Manal Farouk Abdelall
- Department of Microbial Molecular Biology, Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Center (ARC), Giza, Egypt
| | - Omima Mohammed El-Mahdy
- Department of Biological and Geological Sciences, Faculty of Education, Ain Shams University, Cairo, Egypt
| |
Collapse
|
178
|
Cary JW, Entwistle S, Satterlee T, Mack BM, Gilbert MK, Chang PK, Scharfenstein L, Yin Y, Calvo AM. The Transcriptional Regulator Hbx1 Affects the Expression of Thousands of Genes in the Aflatoxin-Producing Fungus Aspergillus flavus. G3 (BETHESDA, MD.) 2019; 9:167-178. [PMID: 30425054 PMCID: PMC6325891 DOI: 10.1534/g3.118.200870] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022]
Abstract
In filamentous fungi, homeobox proteins are conserved transcriptional regulators described to control conidiogenesis and fruiting body formation. Eight homeobox (hbx) genes are found in the genome of the aflatoxin-producing ascomycete, Aspergillus flavus While loss-of-function of seven of the eight genes had little to no effect on fungal growth and development, disruption of hbx1, resulted in aconidial colonies and lack of sclerotial production. Furthermore, the hbx1 mutant was unable to produce aflatoxins B1 and B2, cyclopiazonic acid and aflatrem. In the present study, hbx1 transcriptome analysis revealed that hbx1 has a broad effect on A. flavus gene expression, and the effect of hbx1 increases overtime, impacting more than five thousand protein-coding genes. Among the affected genes, those in the category of secondary metabolism (SM), followed by that of cellular transport, were the most affected. Specifically, regarding the effect of hbx1 on SM, we found that genes in 44 SM gene clusters where upregulated while 49 were downregulated in the absence of hbx1, including genes in the SM clusters responsible for the synthesis of asparasone, piperazine and aflavarin, all known to be associated with sclerotia. In addition, our study revealed that hbx1 affects the expression of other transcription factor genes involved in development, including the conidiation central regulatory pathway and flb genes.
Collapse
Affiliation(s)
- Jeffrey W Cary
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Sarah Entwistle
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Timothy Satterlee
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Brian M Mack
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Matthew K Gilbert
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Perng K Chang
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Leslie Scharfenstein
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Yanbin Yin
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| |
Collapse
|
179
|
Adetunji MC, Ngoma L, Atanda OO, Mwanza M. A polyphasic method for the identification of aflatoxigenic Aspergilla from cashew nuts. World J Microbiol Biotechnol 2019; 35:15. [PMID: 30607686 DOI: 10.1007/s11274-018-2575-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/07/2018] [Indexed: 02/04/2023]
Abstract
The invasion of food by toxigenic fungi is a threat to public health. This study aimed at enumerating the microbial profile, detection of aflatoxin producing genes and quantification of the levels of aflatoxin contamination of cashew nuts meant for human consumption. A polyphasic method of analysis using newly formulated β-Cyclodextrin Neutral Red Desiccated coconut agar (β-CDNRDCA) and Yeast Extract Sucrose agar (YES) with Thin Layer Chromatography (TLC), Polymerase Chain Reaction (PCR) and High Performance Liquid Chromatographic (HPLC) method was adopted in determining the aflatoxigenic potential of the isolates, the presence of aflatoxin biosynthetic gene (aflM, aflD, aflR, aflJ omt-A) and estimation of the total aflatoxin content of the nuts. The fungal counts ranged from 2.0 to 2.4 log10cfu/g and sixty-three fungal isolates belonging to 18 genera and 34 species were isolated. The Aspergillus spp. were the most frequently isolated (50.79%) while Trichoderma spp. (1.59%) were the least. and fluorescence production was enhanced on the newly formulated β-CDNRDCA by the aflatoxigenic species. The aflD gene was amplified in all the isolates while aflM, aflR and aflJ gene were each amplified in 77.77% of the isolates and omt-A gene in 70.37%. The aflatoxin content of the nuts ranged from 0.03 to 0.77 µg/kg and were below the 4 µg/kg EU recommended limit for total aflatoxins. The present work confirms that a single method of analysis may not be sufficient to screen for the presence of aflatoxins in foods, as with a combination of different methods.
Collapse
Affiliation(s)
- Modupeade C Adetunji
- Department of Animal Health, School of Agriculture, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho, 2735, South Africa. .,Department of Biological Sciences, McPherson University, P.M.B. 2094, Seriki Sotayo, Abeokuta, Ogun State, Nigeria.
| | - Lubanza Ngoma
- Department of Animal Health, School of Agriculture, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho, 2735, South Africa.,Food Security and Food Safety Niche Area, North-West University, Private Bag X2046, Mmabatho, 2735, South Africa
| | - Olusegun O Atanda
- Department of Biological Sciences, McPherson University, P.M.B. 2094, Seriki Sotayo, Abeokuta, Ogun State, Nigeria
| | - Mulunda Mwanza
- Department of Animal Health, School of Agriculture, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho, 2735, South Africa.,Food Security and Food Safety Niche Area, North-West University, Private Bag X2046, Mmabatho, 2735, South Africa
| |
Collapse
|
180
|
Ren Y, Jin J, Zheng M, Yang Q, Xing F. Ethanol Inhibits Aflatoxin B 1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes. Front Microbiol 2019. [PMID: 32010073 DOI: 10.3389/fmicb.2019.02946/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
Abstract
As the most carcinogenic, toxic, and economically costly mycotoxins, aflatoxin B1 (AFB1) is primarily biosynthesized by Aspergillus flavus and Aspergillus parasiticus. Aflatoxin biosynthesis is related to oxidative stress and functions as a second line of defense from excessive reactive oxygen species. Here, we find that ethanol can inhibit fungal growth and AFB1 production by A. flavus in a dose-dependent manner. Then, the ethanol's molecular mechanism of action on AFB1 biosynthesis was revealed using a comparative transcriptomic analysis. RNA-Seq data indicated that all the genes except for aflC in the aflatoxin gene cluster were down-regulated by 3.5% ethanol. The drastic repression of aflatoxin structural genes including the complete inhibition of aflK and aflLa may be correlated with the down-regulation of the transcription regulator genes aflR and aflS in the cluster. This may be due to the repression of several global regulator genes and the subsequent overexpression of some oxidative stress-related genes. The suppression of several key aflatoxin genes including aflR, aflD, aflM, and aflP may also be associated with the decreased expression of the global regulator gene veA. In particular, ethanol exposure caused the decreased expression of stress response transcription factor srrA and the overexpression of bZIP transcription factor ap-1, C2H2 transcription factors msnA and mtfA, together with the enhanced levels of anti-oxidant enzymatic genes including Cat, Cat1, Cat2, CatA, and Cu, Zn superoxide dismutase gene sod1. Taken together, these RNA-Seq data strongly suggest that ethanol inhibits AFB1 biosynthesis by A. flavus via enhancing fungal oxidative stress response. In conclusion, this study served to reveal the anti-aflatoxigenic mechanisms of ethanol in A. flavus and to provide solid evidence for its use in controlling AFB1 contamination.
Collapse
Affiliation(s)
- Yaoyao Ren
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Jing Jin
- 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
| | - Mumin Zheng
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Qingli Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Fuguo Xing
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
- 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
| |
Collapse
|
181
|
Chen Y, Kong Q, Liang Y. Three newly identified peptides from Bacillus megaterium strongly inhibit the growth and aflatoxin B1 production of Aspergillus flavus. Food Control 2019. [DOI: 10.1016/j.foodcont.2018.07.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
182
|
Alternative Splicing of the Aflatoxin-Associated Baeyer⁻Villiger Monooxygenase from Aspergillus flavus: Characterisation of MoxY Isoforms. Toxins (Basel) 2018; 10:toxins10120521. [PMID: 30563144 PMCID: PMC6315744 DOI: 10.3390/toxins10120521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/01/2018] [Accepted: 12/03/2018] [Indexed: 01/24/2023] Open
Abstract
Aflatoxins are carcinogenic mycotoxins that are produced by the filamentous fungus Aspergillus flavus, a contaminant of numerous food crops. Aflatoxins are synthesised via the aflatoxin biosynthesis pathway, with the enzymes involved encoded by the aflatoxin biosynthesis gene cluster. MoxY is a type I Baeyer–Villiger monooxygenase (BVMO), responsible for the conversion of hydroxyversicolorone (HVN) and versicolorone (VN) to versiconal hemiacetal acetate (VHA) and versiconol acetate (VOAc), respectively. Using mRNA data, an intron near the C-terminus was identified that is alternatively spliced, creating two possible MoxY isoforms which exist in vivo, while analysis of the genomic DNA suggests an alternative start codon leading to possible elongation of the N-terminus. These four variants of the moxY gene were recombinantly expressed in Escherichia coli, and their activity evaluated with respect to their natural substrates HVN and VN, as well as surrogate ketone substrates. Activity of the enzyme is absolutely dependent on the additional 22 amino acid residues at the N-terminus. Two MoxY isoforms with alternative C-termini, MoxYAltN and MoxYAltNC, converted HVN and VN, in addition to a range of ketone substrates. Stability and flavin-binding data suggest that MoxYAltN is, most likely, the dominant isoform. MoxYAltNC is generated by intron splicing, in contrast to intron retention, which is the most prevalent type of alternative splicing in ascomycetes. The alternative C-termini did not alter the substrate acceptance profile, or regio- or enantioselectivity of the enzyme, but did significantly affect the solubility and stability.
Collapse
|
183
|
Lu X, Luo C, Xing J, Han Z, Li T, Wu W, Xu H, Zhan R, Chen W. Optimization of Storage Conditions of the Medicinal Herb Ilex asprella against the Sterigmatocystin Producer Aspergillus versicolor Using Response Surface Methodology. Toxins (Basel) 2018; 10:toxins10120499. [PMID: 30486344 PMCID: PMC6316290 DOI: 10.3390/toxins10120499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 11/16/2022] Open
Abstract
The root of Ilex asprella is a commonly used herb in Southern China, and also constitutes the main raw material of Canton herbal tea. I. asprella is readily contaminated by mildew because of rich nutrients. Aspergillus versicolor producing sterigmatocystin is one of the most common molds that contaminate foodstuffs and medicinal herbs. Previous study on the evaluation of fungal contamination on samples of I. asprella revealed that A. versicolor was the dominant contaminant. In this study, experiments based on response surface methodology combined with central composite design were carried out to determine the optimal storage conditions of I. asprella to minimize the contamination of sterigmatocystin. The herb, manually innoculated with A. versicolor, was stored under different temperatures (20⁻40 °C) and humidity (80⁻95%) for seven days. The effects of temperature and humidity were evaluated using total saponin, polysaccharide and the sterigmatocystin levels as quality indexes. The results showed that A. versicolor grew quickly and produced large amounts of sterigmatocystin on I. asprella, at humidity ranging from 85% to 90% and temperatures above 26 °C. Meanwhile, total saponin and polysaccharide amounts were reduced significantly. These findings suggested that I. asprella samples should be stored in an environment with humidity and temperature below 85% and 26 °C, respectively, to reduce A. versicolor growth and sterigmatocystin production.
Collapse
Affiliation(s)
- Xiaofang Lu
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- Ministry of Education Key Laboratory of Chinese Medicinal Resource from Lingnan, Guangzhou 510006, China.
- Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou 510006, China.
| | - Chaoquan Luo
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- Ministry of Education Key Laboratory of Chinese Medicinal Resource from Lingnan, Guangzhou 510006, China.
- Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou 510006, China.
| | - Jianyong Xing
- China Resources Sanjiu Medical & Pharmaceutical Co, Ltd., Shenzhen 518110, China.
| | - Zhengzhou Han
- China Resources Sanjiu Medical & Pharmaceutical Co, Ltd., Shenzhen 518110, China.
| | - Tong Li
- School Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Weiwei Wu
- School Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Hui Xu
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- Ministry of Education Key Laboratory of Chinese Medicinal Resource from Lingnan, Guangzhou 510006, China.
- Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou 510006, China.
| | - Ruoting Zhan
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- Ministry of Education Key Laboratory of Chinese Medicinal Resource from Lingnan, Guangzhou 510006, China.
- Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou 510006, China.
| | - Weiwen Chen
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- Ministry of Education Key Laboratory of Chinese Medicinal Resource from Lingnan, Guangzhou 510006, China.
- Joint Laboratory of National Engineering Research Center for the Pharmaceutics of Traditional Chinese Medicines, Guangzhou 510006, China.
| |
Collapse
|
184
|
Akbari Dana M, Kordbacheh P, Daei Ghazvini R, Moazeni M, Nazemi L, Rezaie S. Inhibitory effect of vitamin C on Aspergillus parasiticus growth and aflatoxin gene expression. Curr Med Mycol 2018; 4:10-14. [PMID: 30619963 PMCID: PMC6315201 DOI: 10.18502/cmm.4.3.170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background and Purpose: Aflatoxin is known as one of the most important mycotoxins threatening human life. This toxin is produced by Aspergillus species, which is the common cause of agricultural product contamination. The use of organic compounds has been always considered for the inhibition of fungal growth and toxin production. Regarding this, the aim of the present study was to investigate the effect of vitamin C on the rate of fungal growth, aflR gene expression, and toxin production. Materials and Methods: For the purpose of the study, first, Aspergillus parasiticus ATCC15517 was cultured in Sabouraud dextrose agar medium containing vitamin C at concentrations of 200, 100, 50, 25, 12.5, 6.25, and 3.1 mg/ml and temperature of 28°C for 72 h. Then, the amount of aflatoxin produced in the presence of vitamin C was measured through high performance liquid chromatography. Finally, by extracting the DNA of the cultured samples, the aflR gene expression level was evaluated by means of real-time polymerase chain reaction at different concentrations of vitamin C. Results: The results showed that mycelium deformation was started at the vitamin C concentration of 50 mg/ml, and that only fungal spores were observed at higher concentrations. The levels of total aflatoxin and its subsets, namely B1, B2, G1, and G2, in the presence of vitamin C were estimated as 5.9, 1.9, 0.2, 3.5, and 0.3 ppm, respectively. On the other hand, these values were respectively obtained as 207.5, 73.6, 4.5, 123.4, and 6 ppm in the absence of vitamin C. Measurement of the expression level of aflR genes showed that the level of gene expression decreased to 68% and up to 81% at the vitamin C concentrations of 25 and 50 mg/ml, respectively. Conclusion: This study showed that vitamin C, as a human-compatible compound, could be considered a good agent to protect agricultural products against fungal aflatoxin.
Collapse
Affiliation(s)
- Maryam Akbari Dana
- Division of Molecular Biology, Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Parivash Kordbacheh
- Division of Molecular Biology, Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Roshanak Daei Ghazvini
- Division of Molecular Biology, Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Moazeni
- Invasive Fungi Research Centre, Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ladan Nazemi
- Division of Molecular Biology, Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sasan Rezaie
- Division of Molecular Biology, Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
185
|
Lv Y, Lv A, Zhai H, Zhang S, Li L, Cai J, Hu Y. Insight into the global regulation of laeA in Aspergillus flavus based on proteomic profiling. Int J Food Microbiol 2018; 284:11-21. [DOI: 10.1016/j.ijfoodmicro.2018.06.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/15/2018] [Accepted: 06/29/2018] [Indexed: 12/21/2022]
|
186
|
Liang Y, Kong Q, Yao Y, Xu S, Xie X. Fusion expression and anti-Aspergillus flavus activity of a novel inhibitory protein DN-AflR. Int J Food Microbiol 2018; 290:184-192. [PMID: 30347354 DOI: 10.1016/j.ijfoodmicro.2018.10.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/10/2018] [Accepted: 10/14/2018] [Indexed: 02/06/2023]
Abstract
The regulatory gene (aflR) encodes AflR, a positive regulator of transcriptional pathway that activates aflatoxin biosynthesis. It has been demonstrated in our laboratory that L-Asp-L-Asn (DN) extracted from Bacillus megaterium inhibited the growth of Aspergillus flavus. We fused gene encoding DN with the gene encoding specific dinuclear zinc finger cluster protein of AflR, then fusion protein competed with the AflS-AflR complex for the AflR binding site and significantly improved anti-A. flavus activity (growth of A. flavus and biosynthesis of aflatoxin B1) of DN. The fusion gene dn-aflR was cloned into pET32a and recombinant plasmid was introduced into Escherichia coli BL21. The highest expression was observed after 10 h induction and fusion protein was purified by affinity chromatography column. Compared with DN, the novel fusion protein DN-AflR significantly inhibited the growth of A. flavus and biosynthesis of aflatoxin B1 (P < 0.05). This study promoted the use of competitive inhibition of fusion proteins to reduce the expression of regulatory genes in the biosynthetic pathway of aflatoxin. Moreover, it provided more supports for deep research and industrialization of such novel anti-A. flavus bio-inhibitors and biological control of microbial contamination.
Collapse
Affiliation(s)
- Yuan Liang
- School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong, China
| | - Qing Kong
- School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong, China.
| | - Yao Yao
- School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong, China
| | - Shujing Xu
- School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong, China
| | - Xiang Xie
- School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong, China
| |
Collapse
|
187
|
Buitimea-Cantúa GV, Velez-Haro JM, Buitimea-Cantúa NE, Molina-Torres J, Rosas-Burgos EC. GC-EIMS analysis, antifungal and anti-aflatoxigenic activity of Capsicum chinense and Piper nigrum fruits and their bioactive compounds capsaicin and piperine upon Aspergillus parasiticus. Nat Prod Res 2018; 34:1452-1455. [DOI: 10.1080/14786419.2018.1514395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Génesis V. Buitimea-Cantúa
- Tecnológico de Monterrey, Escuela de Ingeniería y Ciencias, Centro de Biotecnología-FEMSA, Monterrey, México
- Departamento de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados, Irapuato, Guanajuato, México
| | - John M. Velez-Haro
- Laboratorio de Biología Molecular, Departamento de Ingeniería Bioquímica, Instituto Tecnológico de Celaya, Celaya, Guanajuato, México
| | - Nydia E. Buitimea-Cantúa
- Tecnológico de Monterrey, Escuela de Ingeniería y Ciencias, Centro de Biotecnología-FEMSA, Monterrey, México
| | - Jorge Molina-Torres
- Departamento de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados, Irapuato, Guanajuato, México
| | - Ema C. Rosas-Burgos
- Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Hermosillo, Sonora, México
| |
Collapse
|
188
|
Wu ZH, Liu D, Xu Y, Chen JL, Lin WH. Antioxidant xanthones and anthraquinones isolated from a marine-derived fungus Aspergillus versicolor. Chin J Nat Med 2018; 16:219-224. [PMID: 29576058 DOI: 10.1016/s1875-5364(18)30050-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 02/02/2023]
Abstract
Chemical examination of an EtOAc extract of cultured Aspergillus versicolor fungus from deep-sea sediments resulted in the isolation of four xanthones, eight anthraquinones and five alkaloids, including a new xanthone, oxisterigmatocystin D (1) and a new alkaloid, aspergillusine A (13). High resolution electron impact mass spectrometry (HR-EI-MS), FT-IR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds, and the absolute configuration of compound 1 was established by its NMR features and coupling constant. Furthermore, the biosynthesis pathway of these xanthones and anthraquinones were deduced, and their antioxidant activity and cytotoxicity in human cancer cell lines (HTC-8, Bel-7420, BGC-823, A549, and A2780) were evaluated. The trolox equivalent antioxidant capacity (TEAC) assay indicated most of the xanthones and anthraquinones possessing moderate antioxidant activities. The Nrf2-dependent luciferase reporter gene assay revealed that compounds 6, 7, 9, and 12 potentially activated the expression of Nrf2-regulated gene. In addition, compounds 5 and 11 showed weak cytotoxicity on A549 with the IC50 values of 25.97 and 25.60 μmol·L-1, respectively.
Collapse
Affiliation(s)
- Ze-Hong Wu
- The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen 518033, China; State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, China
| | - Dong Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, China
| | - Ying Xu
- Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, College of Life Science, Shenzhen University, Shenzhen 518060, China
| | - Jian-Liang Chen
- The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen 518033, China.
| | - Wen-Han Lin
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, China.
| |
Collapse
|
189
|
Meng S, Tang GL, Pan HX. Enzymatic Formation of Oxygen-Containing Heterocycles in Natural Product Biosynthesis. Chembiochem 2018; 19:2002-2022. [PMID: 30039582 DOI: 10.1002/cbic.201800225] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Indexed: 01/12/2023]
Abstract
Oxygen-containing heterocycles are widely encountered in natural products that display diverse pharmacological properties and have potential benefits to human health. The formation of O-heterocycles catalyzed by different types of enzymes in the biosynthesis of natural products not only contributes to the structural diversity of these compounds, but also enriches our understanding of nature's ability to construct complex molecules. This minireview focuses on the various modes of enzymatic O-heterocyclization identified in natural product biosynthesis and summarizes the possible mechanisms involved in ring closure.
Collapse
Affiliation(s)
- Song Meng
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, University of the Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Gong-Li Tang
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, University of the Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Hai-Xue Pan
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, University of the Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| |
Collapse
|
190
|
Díaz Nieto CH, Granero AM, Zon MA, Fernández H. Sterigmatocystin: A mycotoxin to be seriously considered. Food Chem Toxicol 2018; 118:460-470. [DOI: 10.1016/j.fct.2018.05.057] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/23/2018] [Accepted: 05/25/2018] [Indexed: 01/25/2023]
|
191
|
Delgado J, Rodríguez A, García A, Núñez F, Asensio MA. Inhibitory Effect of PgAFP and Protective Cultures on Aspergillus parasiticus Growth and Aflatoxins Production on Dry-Fermented Sausage and Cheese. Microorganisms 2018; 6:E69. [PMID: 30011880 PMCID: PMC6164858 DOI: 10.3390/microorganisms6030069] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/29/2018] [Accepted: 07/11/2018] [Indexed: 11/17/2022] Open
Abstract
Aflatoxigenic molds can grow and produce aflatoxins on dry-fermented meat and cheese. The small, basic, cysteine-rich antifungal protein PgAFP displays a time-limited inhibitory ability against unwanted molds by increasing reactive oxygen species (ROS), which can lead to increased aflatoxin production. However, calcium abolishes the inhibitory effect of PgAFP on certain Aspergillus spp. To maximize the antifungal effect, this protein may be combined with protective cultures. Yeasts and lactic acid bacteria may counteract the impact of calcium on PgAFP fungal inhibition. The objective of this work was to study the effect of PgAFP and different combined treatments with Debaryomyces hansenii and/or Pediococcus acidilactici against growth of and aflatoxin production by an aflatoxigenic strain of Aspergillus parasiticus in both culture media and dry-fermented foods with low or high calcium levels. Aflatoxins production was increased by PgAFP but dramatically reduced by P. acidilactici in low calcium culture medium, whereas in the Ca-enriched culture medium, all treatments tested led to low aflatoxins levels. To study whether PgAFP and the protective microorganisms interfere with ROS and aflatoxin production, the relative expression of genes foxA, which is involved in peroxisomal β-oxidation, and aflP, which is required for aflatoxin biosynthesis, were evaluated. The aflatoxin overproduction induced by PgAFP seems not to be linked to peroxisomal β-oxidation. The combination of PgAFP and D. hansenii provided a successful inhibitory effect on A. parasiticus growth as well as on aflatoxin production on sliced dry-fermented sausage and cheese ripened up to 15 days, whereas P. acidilactici did not further enhance the protective effect of the two former agents. Therefore, the combined treatment of PgAFP and D. hansenii seems to provide a promising protective mean against aflatoxin-producing A. parasiticus on dry-fermented foods.
Collapse
Affiliation(s)
- Josué Delgado
- Food Hygiene and Safety, Institute of Meat Products, University of Extremadura, 10003 Cáceres, Spain.
| | - Alicia Rodríguez
- Food Hygiene and Safety, Institute of Meat Products, University of Extremadura, 10003 Cáceres, Spain.
| | - Alfredo García
- Food Hygiene and Safety, Institute of Meat Products, University of Extremadura, 10003 Cáceres, Spain.
| | - Félix Núñez
- Food Hygiene and Safety, Institute of Meat Products, University of Extremadura, 10003 Cáceres, Spain.
| | - Miguel A Asensio
- Food Hygiene and Safety, Institute of Meat Products, University of Extremadura, 10003 Cáceres, Spain.
| |
Collapse
|
192
|
Abstract
Sterigmatocystin (STC) is a possible human carcinogen (2B) according to International Agency for Research on Cancer classification and has been associated with immunotoxic and immunomodulatory activity, together with mutagenic effects. It might be found in numerous substrates, from foods and feeds to chronically damp building materials and indoor dust. Although European Food Safety Authority concluded that the exposure to STC to be of low concern for public health, reinforces the need of data concerning exposure of European citizens. Climate change can represent an increased risk of exposure to STC since it is a crucial factor for agro-ecosystem powering fungal colonisation and mycotoxin production This aspect can represent an increased risk for European countries with temperate climates and it was already reported by the scientific community.
Collapse
Affiliation(s)
- Carla Viegas
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal.,Centro de Investigação em Saúde Pública, Escola Nacional de Saúde Pública, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Janne Nurme
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Elena Piecková
- Faculty of Medicine, Slovak Medical University, Bratislava, Slovakia
| | - Susana Viegas
- H&TRC- Health & Technology Research Center, ESTeSL- Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal.,Centro de Investigação em Saúde Pública, Escola Nacional de Saúde Pública, Universidade NOVA de Lisboa, Lisbon, Portugal
| |
Collapse
|
193
|
Zhao X, Zhi QQ, Li JY, Keller NP, He ZM. The Antioxidant Gallic Acid Inhibits Aflatoxin Formation in Aspergillus flavus by Modulating Transcription Factors FarB and CreA. Toxins (Basel) 2018; 10:toxins10070270. [PMID: 29970790 PMCID: PMC6071284 DOI: 10.3390/toxins10070270] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 06/23/2018] [Accepted: 06/27/2018] [Indexed: 12/28/2022] Open
Abstract
Aflatoxin biosynthesis is correlated with oxidative stress and is proposed to function as a secondary defense mechanism to redundant intracellular reactive oxygen species (ROS). We find that the antioxidant gallic acid inhibits aflatoxin formation and growth in Aspergillus flavus in a dose-dependent manner. Global expression analysis (RNA-Seq) of gallic acid-treated A. flavus showed that 0.8% (w/v) gallic acid revealed two possible routes of aflatoxin inhibition. Gallic acid significantly inhibited the expression of farB, encoding a transcription factor that participates in peroxisomal fatty acid β-oxidation, a fundamental contributor to aflatoxin production. Secondly, the carbon repression regulator encoding gene, creA, was significantly down regulated by gallic acid treatment. CreA is necessary for aflatoxin synthesis, and aflatoxin biosynthesis genes were significantly downregulated in ∆creA mutants. In addition, the results of antioxidant enzyme activities and the lipid oxidation levels coupled with RNA-Seq data of antioxidant genes indicated that gallic acid may reduce oxidative stress through the glutathione- and thioredoxin-dependent systems in A. flavus.
Collapse
Affiliation(s)
- Xixi Zhao
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Qing-Qing Zhi
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Jie-Ying Li
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Zhu-Mei He
- The Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
| |
Collapse
|
194
|
Yin G, Hua SST, Pennerman KK, Yu J, Bu L, Sayre RT, Bennett JW. Genome sequence and comparative analyses of atoxigenic Aspergillus flavus WRRL 1519. Mycologia 2018; 110:482-493. [PMID: 29969379 DOI: 10.1080/00275514.2018.1468201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aflatoxins are toxic secondary metabolites produced by Aspergillus flavus and a few other closely related species of Aspergillus. These highly toxigenic and carcinogenic mycotoxins contaminate global food and feed supplies, posing widespread health risks to humans and domestic animals. Field application of nonaflatoxigenic strains of A. flavus to compete against aflatoxigenic strains has emerged as one of the best management practices for reducing aflatoxins contamination, yielding successful commercial products for corn, cotton seed, and peanuts. In this study, we sequenced the genome and transcriptome of atoxigenic (does not produce aflatoxin or cyclopiazonic acid) A. flavus strain WRRL 1519 isolated from a tree nut orchard to define the genetic characteristics of the strain in relation to aflatoxigenic and other nonaflatoxigenic A. flavus strains. WRRL 1519 strain was similar to other strains in size (38.0 Mb), GC content (47.2%), number of predicted secondary metabolite gene clusters (46), and number of putative proteins (12 121). About 87.4% of the predicted proteome had high shared identity with protein sequences derived from other A. flavus genomes. However, the atoxigenic A. flavus strain WRRL 1519 had deletions, or low shared identity, for many genes in the clusters required for aflatoxins and cyclopiazonic acid (CPA) synthesis. Over half of the aflatoxin synthesis gene cluster was missing, and none of the components of the CPA gene cluster were identified with high sequence similarity. Importantly, the strain appeared to maintain functional sequences of several genes thought to be required for high infectivity. Since the ability to grow on target crop is an important attribute for a successful biocontrol agent, these results indicate that the nonaflatoxigenic A. flavus strain WRRL 1519 would be a good candidate as a biocontrol agent for reducing aflatoxin and CPA accumulation in high-value nut crops.
Collapse
Affiliation(s)
- Guohua Yin
- a Department of Plant Biology, Rutgers , The State University of New Jersey , New Brunswick , New Jersey 08901.,b New Mexico Consortium and Pebble Labs , Los Alamos , New Mexico 87544
| | - Sui Sheng T Hua
- c Foodborne Toxin Detection and Prevention Research, Western Regional Research Center, Agricultural Research Service , US Department of Agriculture , Albany , California 94710
| | - Kayla K Pennerman
- a Department of Plant Biology, Rutgers , The State University of New Jersey , New Brunswick , New Jersey 08901
| | - Jiujiang Yu
- d Food Quality Laboratory, Agricultural Research Service , US Department of Agriculture, Beltsville Agricultural Research Center , Beltsville , Maryland 20705
| | - Lijing Bu
- e Center for Evolutionary & Theoretical Immunology, Department of Biology , University of New Mexico , Albuquerque , New Mexico 87131
| | - Richard T Sayre
- b New Mexico Consortium and Pebble Labs , Los Alamos , New Mexico 87544
| | - Joan W Bennett
- a Department of Plant Biology, Rutgers , The State University of New Jersey , New Brunswick , New Jersey 08901
| |
Collapse
|
195
|
Bernáldez V, Córdoba JJ, Delgado J, Bermúdez E, Rodríguez A. Gene expression analysis to predict aflatoxins B1 and G1 contamination in some plant origin foods. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.03.068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
196
|
Ogawara H. Comparison of Strategies to Overcome Drug Resistance: Learning from Various Kingdoms. Molecules 2018; 23:E1476. [PMID: 29912169 PMCID: PMC6100412 DOI: 10.3390/molecules23061476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 11/16/2022] Open
Abstract
Drug resistance, especially antibiotic resistance, is a growing threat to human health. To overcome this problem, it is significant to know precisely the mechanisms of drug resistance and/or self-resistance in various kingdoms, from bacteria through plants to animals, once more. This review compares the molecular mechanisms of the resistance against phycotoxins, toxins from marine and terrestrial animals, plants and fungi, and antibiotics. The results reveal that each kingdom possesses the characteristic features. The main mechanisms in each kingdom are transporters/efflux pumps in phycotoxins, mutation and modification of targets and sequestration in marine and terrestrial animal toxins, ABC transporters and sequestration in plant toxins, transporters in fungal toxins, and various or mixed mechanisms in antibiotics. Antibiotic producers in particular make tremendous efforts for avoiding suicide, and are more flexible and adaptable to the changes of environments. With these features in mind, potential alternative strategies to overcome these resistance problems are discussed. This paper will provide clues for solving the issues of drug resistance.
Collapse
Affiliation(s)
- Hiroshi Ogawara
- HO Bio Institute, Yushima-2, Bunkyo-ku, Tokyo 113-0034, Japan.
- Department of Biochemistry, Meiji Pharmaceutical University, Noshio-2, Kiyose, Tokyo 204-8588, Japan.
| |
Collapse
|
197
|
Lv C, Wang P, Ma L, Zheng M, Liu Y, Xing F. Large-Scale Comparative Analysis of Eugenol-Induced/Repressed Genes Expression in Aspergillus flavus Using RNA-seq. Front Microbiol 2018; 9:1116. [PMID: 29899734 PMCID: PMC5988903 DOI: 10.3389/fmicb.2018.01116] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/11/2018] [Indexed: 11/24/2022] Open
Abstract
Aflatoxin B1 (AFB1), which is mainly produced by Aspergillus flavus and Aspergillus parasiticus, is the most toxic and hepatocarcinogenic polyketide known. Chemical fungicides are currently utilized to reduce this fungal contaminant, but they are potentially harmful to human health and the environment. Therefore, natural anti-aflatoxigenic products are used as sustainable alternatives to control food and feed contamination. For example, eugenol, presents in many essential oils, has been identified as an aflatoxin inhibitor. However, its exact mechanism of inhibition is yet to be clarified. In this study, the anti-aflatoxigenic mechanism of eugenol in A. flavus was determined using a comparative transcriptomic approach. Twenty of twenty-nine genes in the aflatoxin biosynthetic pathway were down-regulated by eugenol. The most strongly down-regulated gene was aflMa, followed by aflI, aflJ, aflCa, aflH, aflNa, aflE, aflG, aflM, aflD, and aflP. However, the expression of the regulator gene aflR did not change significantly and the expression of aflS was slightly up-regulated. The down-regulation of the global regulator gene veA resulted in the up-regulation of srrA, and the down-regulation of ap-1 and mtfA. The early developmental regulator brlA was profoundly up-regulated in A. flavus after eugenol treatment. These results suggested a model in which eugenol improves fungal development by up-regulating the expression of brlA by the suppression of veA expression and inhibits aflatoxin production through the suppression of veA expression. Exposure to eugenol also caused dysregulated transcript levels of the G protein-coupled receptors (GPCRs) and oxylipins genes. A Gene Ontology analysis indicated that the genes that were highly responsive to eugenol were mainly enriched in RNA-binding functions, suggesting that post-transcriptional modification plays a pivotal role in aflatoxin biosynthesis. KEGG analysis showed that ribosome biogenesis was the most dysregulated pathway, suggesting that eugenol dysregulates ribosome biogenesis, which then interrupts the biosynthesis of Nor-1, Ver-1, and OmtA, and prevents aflatoxisomes performing their normal function in aflatoxin production. In conclusion, our results indicated that eugenol inhibited AFB1 production by modulating the expression of structural genes in aflatoxin pathway, fungal antioxidant status, post-transcriptional modifications and biosynthesis of backbone enzymes in A. flavus.
Collapse
Affiliation(s)
- Cong Lv
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Ping Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Longxue Ma
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Mumin Zheng
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Yang Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| | - Fuguo Xing
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture, Beijing, China
| |
Collapse
|
198
|
Shakeel Q, Lyu A, Zhang J, Wu M, Li G, Hsiang T, Yang L. Biocontrol of Aspergillus flavus on Peanut Kernels Using Streptomyces yanglinensis 3-10. Front Microbiol 2018; 9:1049. [PMID: 29875755 PMCID: PMC5974058 DOI: 10.3389/fmicb.2018.01049] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 05/02/2018] [Indexed: 01/11/2023] Open
Abstract
The bacterium, Streptomyces yanglinensis 3-10, shows promise in the control of many phytopathogenic fungi. In this study, S. yanglinensis and its antifungal substances, culture filtrate (CF3-10) and crude extracts (CE3-10), were evaluated for their activity in reducing growth and aflatoxin AFB1 production by Aspergillus flavus, both in vitro and in vivo on peanut kernels. The results showed that in dual culture conditions, S. yanglinensis reduced the mycelial growth of A. flavus about 41% as compared to control. The mycelial growth of A. flavus was completely inhibited on potato dextrose agar amended with CF3-10 at 3% (v/v) or CE3-10 at 2.5 μg/ml. In liquid culture experiments, growth inhibition ranged from 32.3 to 91.9% with reduction in AFB1 production ranging from 46.4 to 93.4% using different concentrations of CF3-10 or CE3-10. For in vivo assays, CF3-10 at 0.133 ml/g (v/w) or CE3-10 at 13.3 μg/g (w/w) reduced the postharvest decay of peanut kernels by inhibiting visible growth of A. flavus leading to an 89.4 or 88.1% reduction in AFB1 detected, respectively. Compared with the controls, CF3-10 and CE3-10 in A. flavus shake culture significantly reduced expression levels of two AFB1 biosynthesis genes, aflR and aflS. Furthermore, electron microscopy observation showed that CF3-10 (2%, v/v) caused hyphae growth to be abnormal and shriveled, cell organelles to degenerate and collapse, large vacuoles to appear. These results suggest that S. yanglinensis 3-10 has potential as an alternative to chemical fungicides in protecting peanut kernels and other agricultural commodities against postharvest decay from A. flavus.
Collapse
Affiliation(s)
- Qaiser Shakeel
- State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, China
| | - Ang Lyu
- State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, China
| | - Jing Zhang
- State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, China
| | - Mingde Wu
- State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, China
| | - Guoqing Li
- State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Long Yang
- State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, China
| |
Collapse
|
199
|
Ámon J, Keisham K, Bokor E, Kelemen E, Vágvölgyi C, Hamari Z. Sterigmatocystin production is restricted to hyphae located in the proximity of hülle cells. J Basic Microbiol 2018; 58:590-596. [PMID: 29733450 DOI: 10.1002/jobm.201800020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/19/2018] [Accepted: 04/22/2018] [Indexed: 12/20/2022]
Abstract
Aspergillus nidulans produces sterigmatocystin, a secondary metabolite mycotoxin, for the protection of its reproductive structures. Previous studies on grazing behavior of fungivore arthropods, regulation of sexual development, and secondary metabolite biosynthesis have revealed the association of sterigmatocystin biosynthesis with sexual reproduction, but the spatial distribution of sterigmatocystin producing hyphae within the colony has never been investigated. In this work, we aimed to locate the site of sterigmatocystin production within the colony by employing a yCFP reporter system. We demonstrated that the stcO promoter is active only in vegetative hyphae that surround groups of hülle cells and the activity decreases and eventually ceases as the distance between the hypha and the hülle cells increases. This phenomenon indicates that the vegetative mycelium might consist of morphologically uniform, but functionally different hyphae.
Collapse
Affiliation(s)
- Judit Ámon
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Kabichandra Keisham
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Eszter Bokor
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Evelyn Kelemen
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Zsuzsanna Hamari
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| |
Collapse
|
200
|
Metabolites Identified during Varied Doses of Aspergillus Species in Zea mays Grains, and Their Correlation with Aflatoxin Levels. Toxins (Basel) 2018; 10:toxins10050187. [PMID: 29735944 PMCID: PMC5983243 DOI: 10.3390/toxins10050187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 04/30/2018] [Accepted: 05/04/2018] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin contamination is associated with the development of aflatoxigenic fungi such as Aspergillus flavus and A. parasiticus on food grains. This study was aimed at investigating metabolites produced during fungal development on maize and their correlation with aflatoxin levels. Maize cobs were harvested at R3 (milk), R4 (dough), and R5 (dent) stages of maturity. Individual kernels were inoculated in petri dishes with four doses of fungal spores. Fungal colonisation, metabolite profile, and aflatoxin levels were examined. Grain colonisation decreased with kernel maturity: milk-, dough-, and dent-stage kernels by approximately 100%, 60%, and 30% respectively. Aflatoxin levels increased with dose at dough and dent stages. Polar metabolites including alanine, proline, serine, valine, inositol, iso-leucine, sucrose, fructose, trehalose, turanose, mannitol, glycerol, arabitol, inositol, myo-inositol, and some intermediates of the tricarboxylic acid cycle (TCA—also known as citric acid or Krebs cycle) were important for dose classification. Important non-polar metabolites included arachidic, palmitic, stearic, 3,4-xylylic, and margaric acids. Aflatoxin levels correlated with levels of several polar metabolites. The strongest positive and negative correlations were with arabitol (R = 0.48) and turanose and (R = −0.53), respectively. Several metabolites were interconnected with the TCA; interconnections of the metabolites with the TCA cycle varied depending upon the grain maturity.
Collapse
|