Inhibitory effects of cold atmospheric plasma on the growth, ergosterol biosynthesis, and keratinase activity in Trichophyton rubrum Atena Shapourzadeh a, b , Neda Rahimi-Verki b , Seyed-Mohammad Atyabi c, * , Masoomeh Shams-Ghahfarokhi d , Zahra Jahanshiri a , Shiva Irani e , Mehdi Razzaghi-Abyaneh a, ** a Department of Mycology, Pasteur Institute of Iran, Tehran,13164, Iran b Department of Biochemistry, Faculty of Basic Science, Islamic Azad University Damghan Branch, Damghan, Iran c Department of Pilot Nanobiotechnology, Pasteur Institute of Iran, Tehran,13164, Iran d Department of Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran e Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran article info Article history: Received 22 March 2016 Received in revised form 3 July 2016 Accepted 16 July 2016 Available online 18 July 2016 Keywords: Cold atmospheric plasma Trichophyton rubrum Growth kinetics Keratinase activity Ergosterol biosynthesis abstract Background: Dermatophytosis is the most important superficial fungal infection which affects nearly 20% of human population worldwide. Recurrence of disease and emerging resistance of Trichophyton rubrum to synthetic antifungals are the main problems in control of dermatophytosis. The purpose of this study was to evaluate the effect of cold atmospheric plasma (CAP) on T. rubrum growth, ergosterol biosynthesis and keratinase activity. Methods: A CAP system, comprised of helium 98% e oxygen 2% (He/O 2 ), was used. Trichophyton rubrum conidia suspensions were treated with CAP in time periods of 90, 120, 150 and 180 s in 96-well microplates. Fungal growth was evaluated by counting the colony forming unit (CFU). Fungal dry weight, ergosterol biosynthesis and keratinase activity were evaluated in CAP-treated T. rubrum and untreated controls. Results: T. rubrum growth was significantly inhibited by 62%e91%. CAP strongly suppressed fungal ergosterol biosynthesis by 27%e54%. The keratinase activity was increased by 7.30%e21.88% up to 120 s CAP exposure. Conclusion: Our results demonstrated for the first time that CAP inhibits T. rubrum growth, suppresses ergosterol biosynthesis and increases moderately keratinase activity in a dose-dependent manner. Overall, CAP exposure could be a potentially useful method for treatment of clinical cases of human and animal dermatophytoses. © 2016 Elsevier Inc. All rights reserved. 1. Introduction Dermatophytes are a group of keratinophilic fungi which contain around 40 species classified into three main genera Microsporum (skin and hair), Trichophyton (skin, hair and nail) and Epidermophyton (skin and nail). Dermatophytosis is a superficial infection in keratinized skin tissue, in nails and hair which is prevalent worldwide. In the etiology of dermatophytosis, 5 major species involved are Trichophyton rubrum, Trichophyton inter- digitale, Trichophyton tonsurans, Microsporum canis, and Trichophy- ton violaceum [1]. They have an arsenal of proteases aimed to digest the keratin network into absorbable oligopeptides or amino acids. Dermatophytes secrete multiple serine-subtilisins and metallo- endoproteases (fungalysins), formerly called keratinases, which are used for penetration into host cellular system [2e5]. The enzyme reduces disulfide bonds in keratins of skin, hair and nail. This reduction depends on a sulfite efflux pump, encoded by the TruSsu1 gene. Keratinase enzyme plays a major role in tinea dis- eases [6]. According to previous studies, the disease incidence is increasing every year and approximately 20%e25% of the world * Corresponding author. Department of Pilot Nanobiotechnology, Pasteur Institute of Iran, Tehran, 13164, Iran. ** Corresponding author. Department of Mycology, Pasteur Institute of Iran, Tehran, 13164, Iran. E-mail addresses: atyabi@pasteur.ac.ir (S.-M. Atyabi), mrab442@yahoo.com, mrab442@pasteur.ac.ir (M. Razzaghi-Abyaneh). Contents lists available at ScienceDirect Archives of Biochemistry and Biophysics journal homepage: www.elsevier.com/locate/yabbi http://dx.doi.org/10.1016/j.abb.2016.07.012 0003-9861/© 2016 Elsevier Inc. All rights reserved. Archives of Biochemistry and Biophysics 608 (2016) 27e33