Cold plasma treatment triggers antioxidative defense system and induces changes in hyphal surface and subcellular structures of Aspergillus flavus

• Published in: Applied microbiology and biotechnology Vol. 102; no. 15; pp. 6647 - 6658
• Main Authors: Šimončicová, Juliana, Kaliňáková, Barbora, Kováčik, Dušan, Medvecká, Veronika, Lakatoš, Boris, Kryštofová, Svetlana, Hoppanová, Lucia, Palušková, Veronika, Hudecová, Daniela, Ďurina, Pavol, Zahoranová, Anna
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2018; Springer; Springer Nature B.V
• Subjects: antioxidant activity; Antioxidants; Antioxidants - metabolism; Apoptosis; Applied Microbial and Cell Physiology; Aspergillus; Aspergillus flavus; Aspergillus flavus - drug effects; Aspergillus flavus - enzymology; atmospheric pressure; Biodegradation; Biological materials; biomass; Biomedical and Life Sciences; Biotechnology; Cell death; Cell surface; Cell walls; chemical structure; Cold plasmas; Cold pressing; Cold treatment; death; Decontamination; Deoxyribonucleic acid; Disintegration; DNA; Drying; Enzymatic activity; enzyme activity; Fluorescence; fluorescence microscopy; Fluorescent dyes; Fluorescent indicators; Fourier transform infrared spectroscopy; Glutathione; Hyphae; Hyphae - drug effects; Iodides; Life Sciences; Membrane permeability; Membranes; Microbial Genetics and Genomics; Microbial Viability - drug effects; Microbiology; Microscopy; Molecular chains; Molecular structure; Mortality; Nuclei; Nuclei (cytology); Organic chemistry; Oxidative stress; Permeability; Physiological aspects; Plasma; Plasma Gases - pharmacology; plasma membrane; propidium; Propidium iodide; Reactive oxygen species; Scanning electron microscopy; Thiobarbituric acid; thiobarbituric acid-reactive substances; Vibrations; Lipid peroxidation; Oxidative stress; FTIR; Cold atmospheric pressure plasma; Antioxidant defense system; Aspergillus flavus
• ISSN: 0175-7598; 1432-0614; 1432-0614
• DOI: 10.1007/s00253-018-9118-y

The cold atmospheric-pressure plasma (CAPP) has become one of the recent effective decontamination technologies, but CAPP interactions with biological material remain the subject of many studies. The CAPP generates numerous types of particles and radiations that synergistically affect cells and tissues differently depending on their structure. In this study, we investigated the effect of CAPP generated by diffuse coplanar surface barrier discharge on hyphae of Aspergillus flavus . Hyphae underwent massive structural changes after plasma treatment. Scanning electron microscopy showed drying hyphae that were forming creases on the hyphal surface. ATR-FTIR analysis demonstrated an increase of signal intensity for C=O and C-O stretching vibrations indicating chemical changes in molecular structures located on hyphal surface. The increase in membrane permeability was detected by the fluorescent dye, propidium iodide. Biomass dry weight determination and increase in permeability indicated leakage of cell content and subsequent death. Disintegration of nuclei and DNA degradation confirmed cell death after plasma treatment. Damage of plasma membrane was related to lipoperoxidation that was determined by higher levels of thiobarbituric acid reactive species after plasma treatment. The CAPP treatment led to rise of intracellular ROS levels detected by fluorescent microscopy using 2′,7′-dichlorodihydrofluorescein diacetate. At the same time, antioxidant enzyme activities increased, and level of reduced glutathione decreased. The results in this study indicated that the CAPP treatment in A. flavus targeted both cell surface structures, cell wall, and plasma membrane, inflicting injury on hyphal cells which led to subsequent oxidative stress and finally cell death at higher CAPP doses.