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Yabe K, Ozaki H, Maruyama T, Hayashi K, Matto Y, Ishizaka M, Makita T, Noma SY, Fujiwara K, Kushiro M. Improvement of the Culture Medium for the Dichlorvos-Ammonia (DV-AM) Method to Selectively Detect Aflatoxigenic Fungi in Soil. Toxins (Basel) 2018; 10:toxins10120519. [PMID: 30563113 PMCID: PMC6316280 DOI: 10.3390/toxins10120519] [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: 11/10/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 11/16/2022] Open
Abstract
The dichlorvos-ammonia (DV-AM) method is a simple but sensitive visual method for detecting aflatoxigenic fungi. Here we sought to develop a selective medium that is appropriate for the growth of aflatoxigenic fungi among soil mycoflora. We examined the effects of different concentrations of carbon sources (sucrose and glucose) and detergents (deoxycholate (DOC), Triton X-100, and Tween 80) on microorganisms in soils, using agar medium supplemented with chloramphenicol. The results demonstrated that 5–10% sucrose concentrations and 0.1–0.15% DOC concentrations were appropriate for the selective detection of aflatoxigenic fungi in soil. We also identified the optimal constituents of the medium on which the normal rapid growth of Rhizopus sp. was completely inhibited. By using the new medium along with the DV-AM method, we succeeded in the isolation of aflatoxigenic fungi from non-agricultural fields in Fukui city, Japan. The fungi were identified as Aspergillus nomius based on their calmodulin gene sequences. These results indicate that the new medium will be useful in practice for the detection of aflatoxigenic fungi in soil samples including those from non-agricultural environments.
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Affiliation(s)
- Kimiko Yabe
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Haruna Ozaki
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Takuya Maruyama
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Keisuke Hayashi
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Yuki Matto
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Marika Ishizaka
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Takeru Makita
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Syun-Ya Noma
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Kousuke Fujiwara
- Department of Environmental and Food Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, 3-6-1 Gakuen, Fukui-shi, Fukui 910-8505, Japan.
| | - Masayo Kushiro
- Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannon-dai, Tsukuba-shi, Ibaraki 305-8642, Japan.
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Abstract
The availability of complete fungal genomes is expanding rapidly and is offering an extensive and accurate view of this "kingdom." The scientific milestone of free access to more than 1000 fungal genomes of different species was reached, and new and stimulating projects have meanwhile been released. The "1000 Fungal Genomes Project" represents one of the largest sequencing initiative regarding fungal organisms trying to fill some gaps on fungal genomics. Presently, there are 329 fungal families with at least one representative genome sequenced, but there is still a large number of fungal families without a single sequenced genome. In addition, additional sequencing projects helped to understand the genetic diversity within some fungal species. The availability of multiple genomes per species allows to support taxonomic organization, brings new insights for fungal evolution in short-time scales, clarifies geographical and dispersion patterns, elucidates outbreaks and transmission routes, among other objectives. Genotyping methodologies analyze only a small fraction of an individual's genome but facilitate the comparison of hundreds or thousands of isolates in a small fraction of the time and at low cost. The integration of whole genome strategies and improved genotyping panels targeting specific and relevant SNPs and/or repeated regions can represent fast and practical strategies for studying local, regional, and global epidemiology of fungi.
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Affiliation(s)
- Ricardo Araujo
- University of Porto, Porto, Portugal; School of Medicine and Health Sciences, Flinders University, Adelaide, SA, Australia.
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