Molecular Immunology 78 (2016) 171–182 Contents lists available at ScienceDirect Molecular Immunology j ourna l ho me pa ge: www.elsevier.com/locate/molimm Pellino-1 derived cationic antimicrobial prawn peptide: Bactericidal activity, toxicity and mode of action Gayathri Ravichandran a,b , Venkatesh Kumaresan a , Mariadhas Valan Arasu c , Naif Abdullah Al-Dhabi c , Munuswamy-Ramanujam Ganesh d , Arun Mahesh e , Arunkumar Dhayalan e , Mukesh Pasupuleti f , Jesu Arockiaraj a,∗ a Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur 603 203, Chennai, Tamil Nadu, India b SRM Research Institute, SRM University, Kattankulathur 603 203, Chennai, Tamil Nadu, India c Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia d Interdisciplinary Institute of Indian System of Medicine, SRM University, Kattankulathur 603 203, Chennai, Tamil Nadu, India e Department of Biotechnology, Pondicherry University, Puducherry 605 014, India f Lab PCN 206, Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226 031, Uttar Pradesh, India a r t i c l e i n f o Article history: Received 22 July 2016 Received in revised form 9 September 2016 Accepted 11 September 2016 Keywords: Pellino Peptide Prawn Membrane permeabilization Electrophoretic mobility a b s t r a c t The antimicrobial peptides (AMPs) are multifunctional molecules which represent significant roles in the innate immune system. These molecules have been well known for decades because of their role as natural antibiotics in both invertebrates and vertebrates. The development of multiple drug resistance against conventional antibiotics brought a greater focus on AMPs in recent years. The cationic peptides, in particular, proven as host defense peptides and are considered as effectors of innate immunity. Among the various innate immune molecules, functions of pellino-1 (Peli-1) have been recently studied for its remarkable role in specific immune functions. In our study, we have identified Peli-1 from the cDNA library of freshwater prawn Macrobrachium rosenbergii (Mr) and analyzed its features using various in- silico methods. Real time PCR analysis showed an induced expression of MrPeli-1 during white spot syndrome virus (WSSV), bacteria (Vibrio harveyi) and lipopolysaccharide (LPS) from Escherichia coli chal- lenge. Also, a cationic AMP named MrDN was derived from MrPeli-1 protein sequence and its activity was confirmed against various pathogenic bacteria. The mode of action of MrDN was determined to be its membrane permeabilization ability against Bacillus cereus ATCC 2106 as well as its DNA binding abil- ity. Further, scanning electron microscopic (SEM) images showed the membrane disruption and leakage of cellular components of B. cereus cells induced by MrDN. The toxicity of MrDN against normal cells (HEK293 cells) was demonstrated by MTT and hemolysis assays. Overall, the results demonstrated the innate immune function of MrPeli-1 with a potential cationic AMP in prawn. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Macrobrachium rosenbergii is a commercially valuable food source and holds the sixth place among the marketable aqua- culture species in Asian countries. The total production of M. rosenbergii was recently reported as 1.4 million tonnes globally. However, frequent occurrence of bacterial and viral infections such as white spot syndrome, white tail disease, luminescent lar- ∗ Corresponding author. E-mail address: jesuaraj@hotmail.com (J. Arockiaraj). val syndrome, bacterial necrosis and white post larval disease in the hatcheries resulted a huge economic crisis in the aquacul- ture industry (Hameed and Bonami, 2012; Chaurasia et al., 2016a). Therefore, the recent research has been focusing on understanding the immune mechanisms underlying the host-pathogen interac- tion. Recently, few immune genes that are potentially involved against the prawn diseases have been reported in M. rosenbergii (Kumaresan et al., 2016). However, the participation of pellino proteins in immune functions has been poorly understood in M. rosenbergii. Pellino proteins are evolutionary conserved proteins and demonstrated to play a crucial role in immune functions. Though http://dx.doi.org/10.1016/j.molimm.2016.09.015 0161-5890/© 2016 Elsevier Ltd. All rights reserved.