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Liu J, Chen H, Lv Y, Wu H, Yang LJ, Zhang J, Huang J, Wang W. Synthesis, Characterization, and Antifungal Activity of Benzimidazole-Grafted Chitosan against Aspergillus flavus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:11185-11194. [PMID: 38687832 DOI: 10.1021/acs.jafc.4c01010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Aspergillus flavus contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1H and 13C NMR). Then, the efficiency of BAC against A. flavus ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/mL) could not completely inhibit the growth of A. flavus. Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.
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Affiliation(s)
- Jing Liu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
| | - Hao Chen
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
| | - Yan Lv
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
| | - Huixiang Wu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
| | - Li-Jun Yang
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
| | - Jiahui Zhang
- Hangzhou Sanyan Biotechnology Co., Ltd., Hangzhou, Zhejiang 310018, PR. China
- Xiuzheng Bio-Medicine Research Institute Co., Ltd., Hangzhou, Zhejiang 310018, PR. China
| | - Jianying Huang
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
| | - Wenjie Wang
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, PR. China
- Hangzhou Sanyan Biotechnology Co., Ltd., Hangzhou, Zhejiang 310018, PR. China
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Barda O, Sadhasivam S, Gong D, Doron-Faigenboim A, Zakin V, Drott MT, Sionov E. Aneuploidy Formation in the Filamentous Fungus Aspergillus flavus in Response to Azole Stress. Microbiol Spectr 2023; 11:e0433922. [PMID: 37358460 PMCID: PMC10433848 DOI: 10.1128/spectrum.04339-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 06/06/2023] [Indexed: 06/27/2023] Open
Abstract
Aspergillus flavus is a mycotoxigenic fungus that contaminates many important agricultural crops with aflatoxin B1, the most toxic and carcinogenic natural compound. This fungus is also the second leading cause of human invasive aspergillosis, after Aspergillus fumigatus, a disease that is particularly prevalent in immunocompromised individuals. Azole drugs are considered the most effective compounds in controlling Aspergillus infections both in clinical and agricultural settings. Emergence of azole resistance in Aspergillus spp. is typically associated with point mutations in cyp51 orthologs that encode lanosterol 14α-demethylase, a component of the ergosterol biosynthesis pathway that is also the target of azoles. We hypothesized that alternative molecular mechanisms are also responsible for acquisition of azole resistance in filamentous fungi. We found that an aflatoxin-producing A. flavus strain adapted to voriconazole exposure at levels above the MIC through whole or segmental aneuploidy of specific chromosomes. We confirm a complete duplication of chromosome 8 in two sequentially isolated clones and a segmental duplication of chromosome 3 in another clone, emphasizing the potential diversity of aneuploidy-mediated resistance mechanisms. The plasticity of aneuploidy-mediated resistance was evidenced by the ability of voriconazole-resistant clones to revert to their original level of azole susceptibility following repeated transfers on drug-free media. This study provides new insights into mechanisms of azole resistance in a filamentous fungus. IMPORTANCE Fungal pathogens cause human disease and threaten global food security by contaminating crops with toxins (mycotoxins). Aspergillus flavus is an opportunistic mycotoxigenic fungus that causes invasive and noninvasive aspergillosis, diseases with high rates of mortality in immunocompromised individuals. Additionally, this fungus contaminates most major crops with the notorious carcinogen, aflatoxin. Voriconazole is the drug of choice to treat infections caused by Aspergillus spp. Although azole resistance mechanisms have been well characterized in clinical isolates of Aspergillus fumigatus, the molecular basis of azole resistance in A. flavus remains unclear. Whole-genome sequencing of eight voriconazole-resistant isolates revealed that, among other factors, A. flavus adapts to high concentrations of voriconazole by duplication of specific chromosomes (i.e., aneuploidy). Our discovery of aneuploidy-mediated resistance in a filamentous fungus represents a paradigm shift, as this type of resistance was previously thought to occur only in yeasts. This observation provides the first experimental evidence of aneuploidy-mediated azole resistance in the filamentous fungus A. flavus.
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Affiliation(s)
- Omer Barda
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Sudharsan Sadhasivam
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Di Gong
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Adi Doron-Faigenboim
- Department of Vegetable and Field Crops, Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Varda Zakin
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Milton T. Drott
- Cereal Disease Laboratory, USDA-ARS, St. Paul, Minnesota, USA
| | - Edward Sionov
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
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Basha NJ. Therapeutic Efficacy of Benzimidazole and Its Analogs: An Update. Polycycl Aromat Compd 2022. [DOI: 10.1080/10406638.2022.2118334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- N. Jeelan Basha
- Department of Chemistry, Indian Academy Degree College-Autonomous Bengaluru, India
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Antifungal Agents in Agriculture: Friends and Foes of Public Health. Biomolecules 2019; 9:biom9100521. [PMID: 31547546 PMCID: PMC6843326 DOI: 10.3390/biom9100521] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 09/12/2019] [Accepted: 09/19/2019] [Indexed: 12/14/2022] Open
Abstract
Fungal diseases have been underestimated worldwide but constitute a substantial threat to several plant and animal species as well as to public health. The increase in the global population has entailed an increase in the demand for agriculture in recent decades. Accordingly, there has been worldwide pressure to find means to improve the quality and productivity of agricultural crops. Antifungal agents have been widely used as an alternative for managing fungal diseases affecting several crops. However, the unregulated use of antifungals can jeopardize public health. Application of fungicides in agriculture should be under strict regulation to ensure the toxicological safety of commercialized foods. This review discusses the use of antifungals in agriculture worldwide, the need to develop new antifungals, and improvement of regulations regarding antifungal use.
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