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Air Atmospheric Pressure Plasma Jet to Improve Fruiting Body Production and Enhance Bioactive Phytochemicals from Mutant Cordyceps militaris (White Cordyceps militaris). FOOD BIOPROCESS TECH 2023. [DOI: 10.1007/s11947-023-03028-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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Intensified inactivation of model and environmental bacteria by an atmospheric-pressure air-liquid discharge plasma compared with chlorination. J Environ Sci (China) 2022; 117:80-90. [PMID: 35725092 DOI: 10.1016/j.jes.2022.01.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/18/2022] [Accepted: 01/23/2022] [Indexed: 11/21/2022]
Abstract
Water-borne pathogenic bacteria are always the top priority to be removed through disinfection process in water treatment due to their threat to human health. It was necessary to develop novel disinfection methods since the conventional chlorine disinfection was inefficient in inactivating chlorine-resistant bacteria, inducing the viable but non-culturable (VBNC) bacteria and forming disinfection by-products (DBPs). In this study, the inactivation of four model strains including Gram-negative (G-), Gram-positive (G+) and environmental samples by atmospheric-pressure air-liquid discharge plasma (ALDP) was assessed systematically. The results showed that ALDP was superior in inactivating all of the samples compared with chlorination. During 10 min ALDP treatment, the G- bacteria were completely inactivated, and the G+ one was inactivated by more than 4.61 logs. The inactivation of bacteria from a campus lake and a wastewater treatment plant effluent exceeded 99.82% and 97.78%, respectively. For G- bacteria, ALDP resulted in a much lower (102∼103 times) levels of VBNC cells than chlorination. ALDP could effectively remove the chlorine-resistant bacteria. More than 96.41% of the intracellular DNA and 99.99% of the extracellular DNA were removed, whereas it was only 56.35% and 12.82% for chlorination. ALDP had a stronger ability to destroy cell structure than chlorination, presumably due to the existence of ROS (·OH, 1O2 and O2-). GC-MS analysis showed that ALDP produced less DBPs than chlorination. These findings provided new insights for the application of discharge plasma in water disinfection, which could be complemental or alternative to the conventional disinfection methods.
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Veerana M, Yu N, Ketya W, Park G. Application of Non-Thermal Plasma to Fungal Resources. J Fungi (Basel) 2022; 8:jof8020102. [PMID: 35205857 PMCID: PMC8879654 DOI: 10.3390/jof8020102] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/15/2022] [Accepted: 01/20/2022] [Indexed: 12/21/2022] Open
Abstract
In addition to being key pathogens in plants, animals, and humans, fungi are also valuable resources in agriculture, food, medicine, industry, and the environment. The elimination of pathogenic fungi and the functional enhancement of beneficial fungi have been the major topics investigated by researchers. Non-thermal plasma (NTP) is a potential tool to inactivate pathogenic and food-spoiling fungi and functionally enhance beneficial fungi. In this review, we summarize and discuss research performed over the last decade on the use of NTP to treat both harmful and beneficial yeast- and filamentous-type fungi. NTP can efficiently inactivate fungal spores and eliminate fungal contaminants from seeds, fresh agricultural produce, food, and human skin. Studies have also demonstrated that NTP can improve the production of valuable enzymes and metabolites in fungi. Further studies are still needed to establish NTP as a method that can be used as an alternative to the conventional methods of fungal inactivation and activation.
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Affiliation(s)
- Mayura Veerana
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Korea; (M.V.); (N.Y.); (W.K.)
| | - Nannan Yu
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Korea; (M.V.); (N.Y.); (W.K.)
| | - Wirinthip Ketya
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Korea; (M.V.); (N.Y.); (W.K.)
| | - Gyungsoon Park
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Korea; (M.V.); (N.Y.); (W.K.)
- Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Korea
- Correspondence: ; Tel.: +82-2-940-8324
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Lee GJ, Lamichhane P, Ahn SJ, Kim SH, Yewale MA, Choong CE, Jang M, Choi EH. Nitrate Capture Investigation in Plasma-Activated Water and Its Antifungal Effect on Cryptococcus pseudolongus Cells. Int J Mol Sci 2021; 22:12773. [PMID: 34884579 PMCID: PMC8657772 DOI: 10.3390/ijms222312773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 11/22/2022] Open
Abstract
This research investigated the capture of nitrate by magnesium ions in plasma-activated water (PAW) and its antifungal effect on the cell viability of the newly emerged mushroom pathogen Cryptococcus pseudolongus. Optical emission spectra of the plasma jet exhibited several emission bands attributable to plasma-generated reactive oxygen and nitrogen species. The plasma was injected directly into deionized water (DW) with and without an immersed magnesium block. Plasma treatment of DW produced acidic PAW. However, plasma-activated magnesium water (PA-Mg-W) tended to be neutralized due to the reduction in plasma-generated hydrogen ions by electrons released from the zero-valent magnesium. Optical absorption and Raman spectra confirmed that nitrate ions were the dominant reactive species in the PAW and PA-Mg-W. Nitrate had a concentration-dependent antifungal effect on the tested fungal cells. We observed that the free nitrate content could be controlled to be lower in the PA-Mg-W than in the PAW due to the formation of nitrate salts by the magnesium ions. Although both the PAW and PA-Mg-W had antifungal effects on C. pseudolongus, their effectiveness differed, with cell viability higher in the PA-Mg-W than in the PAW. This study demonstrates that the antifungal effect of PAW could be manipulated using nitrate capture. The wide use of plasma therapy for problematic fungus control is challenging because fungi have rigid cell wall structures in different fungal groups.
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Affiliation(s)
- Geon Joon Lee
- Department of Electrical and Biological Physics, Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, Korea; (P.L.); (M.A.Y.)
| | - Pradeep Lamichhane
- Department of Electrical and Biological Physics, Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, Korea; (P.L.); (M.A.Y.)
| | - Seong Jae Ahn
- Department of Microbiology, Institute of Biodiversity, Dankook University, Cheonan 31116, Korea;
| | - Seong Hwan Kim
- Department of Microbiology, Institute of Biodiversity, Dankook University, Cheonan 31116, Korea;
| | - Manesh Ashok Yewale
- Department of Electrical and Biological Physics, Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, Korea; (P.L.); (M.A.Y.)
| | - Choe Earn Choong
- Department of Environmental Engineering, Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, Korea; (C.E.C.); (M.J.)
| | - Min Jang
- Department of Environmental Engineering, Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, Korea; (C.E.C.); (M.J.)
| | - Eun Ha Choi
- Department of Electrical and Biological Physics, Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, Korea; (P.L.); (M.A.Y.)
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Xu H, Zhu Y, Du M, Wang Y, Ju S, Ma R, Jiao Z. Subcellular mechanism of microbial inactivation during water disinfection by cold atmospheric-pressure plasma. WATER RESEARCH 2021; 188:116513. [PMID: 33091801 DOI: 10.1016/j.watres.2020.116513] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/15/2020] [Accepted: 10/10/2020] [Indexed: 06/11/2023]
Abstract
Although the identification of effective reactive oxygen species (ROS) generated by plasma has been extensively studied, yet the subcellular mechanism of microbial inactivation has never been clearly elucidated in plasma disinfection processes. In this study, subcellular mechanism of yeast cell inactivation during plasma-liquid interaction was revealed in terms of comprehensive factors including cell morphology, membrane permeability, lipid peroxidation, membrane potential, intracellular redox homeostasis (intracellular ROS and H2O2, and antioxidant system (SOD, CAT and GSH)), intracellular ionic equilibrium (intracellular H+ and K+) and energy metabolism (mitochondrial membrane potential, intracellular Ca2+ and ATP level). The ROS analysis show that ·OH, 1O2, ·O2-and H2O2 were generated in this plasma-liquid interaction system and ·O2-served as the precursor of 1O2. Additionally, the solution pH was reduced. Plasma can effectively inactivate yeast cells mainly via apoptosis by damaging cell membrane, intracellular redox and ion homeostasis and energy metabolism as well as causing DNA fragmentation. ROS scavengers (l-His, d-Man and SOD) and pH buffer (phosphate buffer solution, PBS) were employed to investigate the role of five antimicrobial factors (·OH, 1O2, ·O2-, H2O2 and low pH) in plasma sterilization. Results show that they have different influences on the aforementioned cell physiological activities. The ·OH and 1O2 contributed most to the yeast inactivation. The ·OH mainly attacked cell membrane and increased cell membrane permeability. The disturb of cell energy metabolism was mainly attributed to 1O2. The damage of cell membrane as well as extracellular low pH could break the intracellular ionic equilibrium and further reduce cell membrane potential. The remarkable increase of intracellular H2O2 was mainly due to the influx of extracellular H2O2 via destroyed cell membrane, which played a little role in yeast inactivation during 10-min plasma treatment. These findings provide comprehensive insights into the antimicrobial mechanism of plasma, which can promote the development of plasma as an alternative water disinfection strategy.
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Affiliation(s)
- Hangbo Xu
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China
| | - Yupan Zhu
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China
| | - Mengru Du
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China
| | - Yuqi Wang
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China
| | - Siyao Ju
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China
| | - Ruonan Ma
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China.
| | - Zhen Jiao
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, China.
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Ott LC, Appleton HJ, Shi H, Keener K, Mellata M. High voltage atmospheric cold plasma treatment inactivates Aspergillus flavus spores and deoxynivalenol toxin. Food Microbiol 2020; 95:103669. [PMID: 33397632 DOI: 10.1016/j.fm.2020.103669] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 10/23/2022]
Abstract
Fungal contamination is a concern for the food industry. Fungal spores resist food sterilization treatments and produce mycotoxins that are toxic for animals and humans. Technologies that deactivate spores and toxins without impacting food quality are desirable. This study demonstrates the efficiency of a high voltage atmospheric cold plasma (HVACP) technology using air to generate reactive oxygen (ROS) and nitrogen (RNS) species for the degradation of Aspergillus flavus cultures and the deoxynivalenol (DON) mycotoxin. Optical emission and absorption spectroscopy demonstrate ionization of hydroxyl groups, atomic oxygen and nitrogen, and confirm production of ROS and RNS, e.g. O3, NO2, NO3, N2O4, and N2O5. Fungal cultures show a depletion in pigmentation and an ~50% spore inactivation after 1-min treatments. Treated spores show surface ablation and membrane degradation by scanning electron microscopy. Twenty-minute direct HVACP treatments of 100 μg of DON in one mL aqueous suspensions resulted in a greater than 99% reduction in DON structure and rescued over 80% of Caco-2 cell viability; however, the same treatment on 100 μg of powdered DON toxin only showed a 33% reduction in DON and only rescued 15% of cell viability. In summary, HVACP air treatment can inactivate both fungal spores and toxins in minutes.
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Affiliation(s)
- Logan C Ott
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, USA
| | - Holly J Appleton
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA
| | - Hu Shi
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA
| | - Kevin Keener
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA
| | - Melha Mellata
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, USA.
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Influence of Nonthermal Atmospheric Plasma-Activated Water on the Structural, Optical, and Biological Properties of Aspergillus brasiliensis Spores. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10186378] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Plasma-activated water (PAW) has emerged as a platform for sterilizing fungal pathogens. In this study, we investigated the influence of PAW on black melanized spores of Aspergillus brasiliensis to explore the mechanism of fungal spore inactivation. PAW was prepared by activating deionized water with a nonthermal atmospheric pressure air plasma jet (soft plasma jet). The concentrations of H2O2 and NOx in the PAW treated by the soft plasma jet for 3 min were 50 μM and 1.8 mM, respectively, and the pH of the PAW was 3.10. The reactive oxygen and nitrogen species (RONS) in the PAW increased with longer plasma activation time. After being treated for 30 min in the PAW with a plasma activation time of 3 min, the spore viability dramatically dropped to 15%. The viabilities of 0.3% H2O2- and 0.3% HNO3-treated spores were 22% and 42%, respectively. The breakage of the spore cell wall by the PAW was revealed in scanning electron microscope images and flow cytometry measurements. Disruption of cell wall integrity provides a path for intracellular components to escape and RONS of the PAW can attack intracellular components directly. Degradation of high molecular genomic DNA was also observed by agarose gel electrophoresis. These results suggest that long-lived reactive species generated in the PAW play an important role in the inactivation of melanized fungal spores. Consequently, PAW produced by a soft plasma jet can be applied to sterilize bioprotective walled fungal spores in a relatively large volume.
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Xu H, Ma R, Zhu Y, Du M, Zhang H, Jiao Z. A systematic study of the antimicrobial mechanisms of cold atmospheric-pressure plasma for water disinfection. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:134965. [PMID: 31740060 DOI: 10.1016/j.scitotenv.2019.134965] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/11/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Waterborne diseases caused by pathogenic microorganisms pose a severe threat to human health. Cold atmospheric-pressure plasma (CAP) has recently gained much interest as a promising fast, effective, economical and eco-friendly method for water disinfection. However, the antimicrobial mechanism of CAP in aqueous environments is still not clearly understood. Herein, we investigate the role of several short-lived reactive oxygen species (ROS) and cellular responses in the CAP inactivation of yeast cells in water. The results show that singlet oxygen (1O2), hydroxyl radical (OH) and superoxide anion (O2-) are generated in this plasma-water system, and O2- served as the precursor of OH. The 5-min plasma treatment resulted in the effective inactivation (more than 2-log reduction) of yeast cells in water. The ROS scavengers significantly increased the survival ratio in the following order: water < D-Man (scavenging OH) < SOD (scavenging O2-) < L-His (scavenging 1O2), indicating that 1O2 contributes the most to the yeast inactivation. In addition, the acidic pH had a synergetic antimicrobial effect with ROS against the yeast cells. During the CAP inactivation process, yeast cells underwent apoptosis in the first 3 min due to the accumulation of intracellular ROS, mitochondrial dysfunction and intracellular acidification, later followed by necrosis under longer exposure times, attributed to the destruction of the cell membrane. Additionally, L-His could switch the cell fate from necrosis to apoptosis through mitigating plasma-induced oxidative stress, indicating that the level of oxidative stress is a critical factor for cell death fate determination. These findings provide comprehensive insights into the antimicrobial mechanism of CAP, which can promote the development of CAP as an alternative water disinfection strategy.
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Affiliation(s)
- Hangbo Xu
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, PR China
| | - Ruonan Ma
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, PR China.
| | - Yupan Zhu
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, PR China
| | - Mengru Du
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, PR China
| | - Hua Zhang
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, PR China; School of Food and Bioengineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450000, PR China
| | - Zhen Jiao
- Henan Key Laboratory of Ion-beam Bioengineering, College of Agricultural Science, Zhengzhou University, Zhengzhou 450052, PR China.
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Spore Viability and Cell Wall Integrity of Cordyceps pruinosa Treated with an Electric Shock-Free, Atmospheric-Pressure Air Plasma Jet. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9183921] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Atmospheric-pressure Ar plasma jets are known to be detrimental to Cordyceps pruinosa spores. However, it is not clear what kinds of reactive species are more effective with regard to fungal cell death. Herein, we study which reactive species plays pivotal roles in the death of fungal spores using an electric shock-free, atmospheric-pressure air plasma jet, simply called soft plasma jet. Plasma treatment significantly reduced the spore viability and damaged fungal DNA. As observed from the circular dichroism spectra, scanning electron microscope images, and flow cytometric measurements, cell wall integrity was decreased by reactive oxygen and nitrogen species (RONS) from the plasma itself and the plasma-activated water. Consequently, degradation of the spore cell wall allows RONS from the plasma to reach the intracellular components. Such plasma-induced intracellular RONS can attack spore DNA and other intracellular components, as confirmed by electrophoresis analysis and phosphorylated histone measurement. In addition, weakening of the spore cell wall allowed for the loss of intracellular components, which can lead to cell death. Plasma radicals were investigated by measuring the optical emission spectrum of the soft plasma jet, and intracellular reactive oxygen species were confirmed by measuring the fluorescence of 2′, 7′-dichlorodihydrofluorescein-diacetate (H2DCF-DA)-stained spores. The soft plasma jet generated considerable amounts of H2O2 and NOx but a very small number of OH radicals as compared to the atmospheric-pressure Arplasma jet; this indicates that plasma-induced long-lived reactive species (H2O2 and NOx) play an important role in the weakening of spore cell walls and cell death.
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