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Xu X, Cao R, Li K, Wan Q, Wu G, Lin Y, Huang T, Wen G. The protective role and mechanism of melanin for Aspergillus niger and Aspergillus flavus against chlorine-based disinfectants. WATER RESEARCH 2022; 223:119039. [PMID: 36084430 DOI: 10.1016/j.watres.2022.119039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/20/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
Melanin is a critical component of fungal cell wall which protect fungi from adverse environmental tress. However, the role of melanin for fungi during the disinfection with chlorine-based disinfectants has not been elucidated. The results showed that the inactivation rate constants of Aspergillus niger with chlorine and chlorine dioxide decreased from 0.08 to 2.10 min-1 to 0 after addition of 0.32 mg/L melanin. The results indicated addition of extracted fungal melanin inhibited the inactivation efficiency of chlorine and chlorine dioxide. In contrast, the k of Aspergillus niger after inactivation with monochloramine ranged from 1.50 to 1.78 min-1 after addition of melanin which indicated effect of melanin on the inactivation efficiency of monochloramine was negligible. In addition, the extracted fungal melanin exhibited high reactivity with chlorine and chlorine dioxide but very low reactivity with monochloramine. The different inactivation mechanisms of chlorine-based disinfectants and different reactivity of melanin with chlorine-based disinfectants led to the different protective mechanism of melanin for A. niger and A. flavus spores against disinfection with chlorine-based disinfectants. The chlorine and chlorine dioxide appeared to react with functional groups of melanin in cell wall of spores, so sacrificial reactions between melanin and disinfectants decreased the available disinfectants and limited the diffusion of disinfectants to the reactive site on cell membrane, which led to the decrease of the disinfection efficiency for chlorine and chlorine dioxide. The monochloramine could penetrate into cell and damage DNA without the effect of melanin due to its strong penetration and low reactivity with melanin. Our results systematically demonstrate the protective roles of melanin on the fungal spores against chlorine-based disinfectants and the underlying mechanisms in resisting the environmental stress caused by chlorine-based disinfectants, which provides important implications for the control of fungi, especially for fungi producing melanin.
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Affiliation(s)
- Xiangqian Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ruihua Cao
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Kai Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Qiqi Wan
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Gehui Wu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yuzhao Lin
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Gang Wen
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architectur and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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Shittu OB, Iwaloye OF, Oloyede AR, Oni EO, Ajibola AT, Arowosegbe AO, Oluwasanya GO. Water safety, antifungal resistant aflatoxigenic
Aspergillus flavus
and other pathogenic fungi in a community hand‐dug wells. J Appl Microbiol 2022; 133:673-682. [DOI: 10.1111/jam.15559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 03/26/2022] [Accepted: 03/30/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Olufunke Bolatito Shittu
- Department of Microbiology; College of Biosciences Federal University of Agriculture Abeokuta Nigeria
| | - Opeoluwa Favour Iwaloye
- Department of Microbiology; College of Biosciences Federal University of Agriculture Abeokuta Nigeria
| | - Adejare Rasak Oloyede
- Department of Microbiology; College of Biosciences Federal University of Agriculture Abeokuta Nigeria
| | - Eniola Oluyemisi Oni
- Department of Microbiology; College of Biosciences Federal University of Agriculture Abeokuta Nigeria
| | - Abiola Tosin Ajibola
- Department of Microbiology; College of Biosciences Federal University of Agriculture Abeokuta Nigeria
| | | | - Grace Olutope Oluwasanya
- Department of Water Resources Management and Agricultural Meteorology; College of Environmental Management and Toxicology Federal University of Agriculture Abeokuta Nigeria
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Abstract
The exact cause of the disproportionate increase in COVID-19-associated mucormycosis (CAM) cases in India remains unknown. Most researchers consider the major cause of India’s CAM epidemic to be the conjunction of the COVID-19 pandemic and associated corticosteroid treatment with the enormous number of Indians with diabetes mellitus (DM). However, excess CAM cases were not seen to the same extent in the Western world, where diabetes is prevalent and corticosteroids are also used extensively for COVID-19 treatment. Herein, we hypothesize that previously overlooked environmental factors specific to India were important contributors to the country’s CAM epidemic. Specifically, we propose that the spread of fungal spores, mainly through fumes generated from the burning of Mucorales-rich biomass, like cow dung and crop stubble, caused extensive environmental exposure in the context of a large population of highly vulnerable patients with DM and COVID-19. Testing this hypothesis with epidemiologic studies, phylogenetic analyses, and strategic environmental sampling may have implications for preventing future epidemics.
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Novak Babič M, Gunde-Cimerman N. Water-Transmitted Fungi are Involved in Degradation of Concrete Drinking Water Storage Tanks. Microorganisms 2021; 9:microorganisms9010160. [PMID: 33445679 PMCID: PMC7828128 DOI: 10.3390/microorganisms9010160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 11/16/2022] Open
Abstract
Global warming, globalization, industrialization, and the rapidly growing population at present increasingly affect the production of safe drinking water. In combination with sustainable bio-based or recycled materials, used for water distribution systems, these factors promote emerging pathogens, including fungi. They can proliferate in oligotrophic water systems, affect the disinfection process, degrade building materials, and cause diseases in humans. In this study, we explored fungal-based degradation of modern concrete water storage tanks and the presence of fungi in chlorinated drinking water at the entrance and exit of the tanks. The degradation potential of isolated 52 fungal strains and their growth at different oligotrophic conditions was tested in vitro. Forty percent of strains grew at extremely oligotrophic conditions, and 50% classified as aerophilic. Two-thirds of tested strains produced acids, with Penicillium strains as the best producers. Only 29.7% of the strains were able to grow at 37 °C, and none of them was isolated from drinking water at consumers' taps. Although not yet part of the guidelines for building materials in contact with drinking water, fungi should be taken into consideration in case of visible degradation. Their number of consumers' endpoints should be checked to exclude possible health risks for consumers.
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Afonso TB, Simões LC, Lima N. Occurrence of filamentous fungi in drinking water: their role on fungal-bacterial biofilm formation. Res Microbiol 2020; 172:103791. [PMID: 33197515 DOI: 10.1016/j.resmic.2020.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
Water is indispensable to life and safe and accessible supply must be available to all. The presence of microorganisms is a threat to this commitment. Biofilms are the main reservoir of microorganisms inside water distribution systems and they are extremely ecologically diverse. Filamentous fungi and bacteria can coexist inside these systems forming inter-kingdom biofilms. This review has the goal of summarizing the most relevant and recent reports on the occurrence of filamentous fungi in water distribution systems along with the current knowledge and gaps about filamentous fungal biofilm formation. Special focus is given on fungal-bacterial interactions in water biofilms.
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Affiliation(s)
| | | | - Nelson Lima
- CEB, Centre of Biological Engineering, University of Minho, Braga, Portugal.
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Góralska K, Błaszkowska J, Dzikowiec M. The occurrence of potentially pathogenic filamentous fungi in recreational surface water as a public health risk. JOURNAL OF WATER AND HEALTH 2020; 18:127-144. [PMID: 32300087 DOI: 10.2166/wh.2020.096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microfungi occurring in surface water may represent an important health risk. Recreational water reservoirs are a potential reservoir of pathogenic fungi. The aim of the study was to assess the diversity of mycobiota in selected artificial bathing reservoirs with regard to its biosafety for the human population. The studies were conducted during the summer of 2016 in three research seasons (June (I), July and August (II), and September (III)), taking into account the various periods of recreational activities. Filamentous fungi were isolated from water samples collected at five different ponds utilized for recreation. From 162 water samples, 149 fungal taxa of filamentous fungi were identified: 140 were classified to species level and only nine to genus level. Aspergillus fumigatus was the dominant species. The highest species richness (S) was noted in June, with 93 fungal taxa (Menhinick's index from 2.65 to 4.49). Additionally, in season I, the highest diversity of fungal species was revealed (Simpson's diversity index from 0.83 to 0.99). The average number of CFU/1 mL sample ranged between 0.4 and 4.6 depending on the time of sampling and ponds. Of all the isolated species, 128 were clinically relevant (11 from RG-2 and 117 from RG-1), highlighting the need to introduce seasonal mycological monitoring of such reservoirs.
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Affiliation(s)
- Katarzyna Góralska
- Department of Biology and Parasitology Medical University of Lodz, Pomorska 251, 92-213 Lodz, Poland E-mail:
| | - Joanna Błaszkowska
- Department of Biology and Parasitology Medical University of Lodz, Pomorska 251, 92-213 Lodz, Poland E-mail:
| | - Magdalena Dzikowiec
- Department of Biomedicine and Genetics Medical University of Lodz, Pomorska 251, 92-213 Lodz, Poland
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