Copper-zinc-superoxide dismutase (CuZnSOD), an antioxidant gene from seahorse (Hippocampus abdominalis); molecular cloning, sequence characterization, antioxidant activity and potential peroxidation function of its recombinant protein

Perera, N.C.N.,Godahewa, G.I.,Lee, J. Academic Press 2016 FISH AND SHELLFISH IMMUNOLOGY Vol.57 No.-

Copper-zinc-superoxide dismutase (CuZnSOD) from Hippocampus abdominalis (HaCuZnSOD) is a metalloenzyme which belongs to the ubiquitous family of SODs. Here, we determined the characteristic structural features of HaCuZnSOD, analyzed its evolutionary relationships, and identified its potential immune responses and biological functions in relation to antioxidant defense mechanisms in the seahorse. The gene had a 5' untranslated region (UTR) of 67 bp, a coding sequence of 465 bp and a 3' UTR of 313 bp. The putative peptide consists of 154 amino acids. HaCuZnSOD had a predicted molecular mass of 15.94 kDa and a theoretical pI value of 5.73, which is favorable for copper binding activity. In silico analysis revealed that HaCuZnSOD had a prominent Cu-Zn_superoxide_dismutase domain, two Cu/Zn signature sequences, a putative N-glycosylation site, and several active sites including Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> binding sites. The three dimensional structure indicated a β-sheet barrel with 8 β-sheets and two short α-helical regions. Multiple alignment analyses revealed many conserved regions and active sites among its orthologs. The highest amino acid identity to HaCuZnSOD was found in Siniperca chuatsi (87.4%), while Maylandia zebra shared a close relationship in the phylogenetic analysis. Functional assays were performed to assess the antioxidant, biophysical and biochemical properties of overexpressed recombinant (r) HaCuZnSOD. A xanthine/XOD assay gave optimum results at pH 9 and 25 <SUP>o</SUP>C indicating these may be the best conditions for its antioxidant action in the seahorse. An MTT assay and flow cytometry confirmed that rHaCuZnSOD showed peroxidase activity in the presence of HCO<SUB>3</SUB><SUP>-</SUP>. In all the functional assays, the level of antioxidant activity of rHaCuZnSOD was concentration dependent; metal ion supplementation also increased its activity. The highest mRNA expressional level of HaCuZnSOD was found in blood. Temporal assessment under pathological stress showed a delay response by HaCuZnSOD. Our findings demonstrated that HaCuZnSOD is an important antioxidant, which might be involved in the host antioxidant defense mechanism against oxidative stress.

Mitogen–activated protein kinase 1 from disk abalone (<i>Haliotis discus discus</i>): Roles in early development and immunity-related transcriptional responses

Perera, N.C.N.,Godahewa, G.I.,Lee, Jehee Elsevier 2016 FISH AND SHELLFISH IMMUNOLOGY Vol.59 No.-

<P><B>Abstract</B></P> <P>Mitogen–activated protein kinase (MAPK) is involved in the regulation of cellular events by mediating signal transduction pathways. MAPK1 is a member of the extracellular-signal regulated kinases (ERKs), playing roles in cell proliferation, differentiation, and development. This is mainly in response to growth factors, mitogens, and many environmental stresses. In the current study, we have characterized the structural features of a homolog of MAPK1 from disk abalone (AbMAPK1). Further, we have unraveled its expressional kinetics against different experimental pathogenic infections or related chemical stimulants. AbMAPK1 harbors a 5′ untranslated region (UTR) of 23 bps, a coding sequence of 1104 bps, and a 3′ UTR of 448 bp. The putative peptide comprises a predicted molecular mass of 42.2 kDa, with a theoretical <I>p</I>I of 6.28. Based on the <I>in silico</I> analysis, AbMAPK1 possesses two <I>N</I>-glycosylation sites, one S_TK catalytic domain, and a conserved His-Arg-Asp domain (HRD). In addition, a conservative glycine rich ATP-phosphate-binding loop and a threonine-x-tyrosine motif (TEY) important for the autophosphorylation were also identified in the protein. Homology assessment of AbMAPK1 showed several conserved regions, and ark clam (<I>Aplysia californica</I>) showed the highest sequence identity (87.9%). The phylogenetic analysis supported close evolutionary kinship with molluscan orthologs. Constitutive expression of <I>AbMAPK1</I> was observed in six different tissues of disk abalone, with the highest expression in the digestive tract, followed by the gills and hemocytes. Highest <I>AbMAPK1</I> mRNA expression level was detected at the trochophore developmental stage, suggesting its role in abalone cell differentiation and proliferation. Significant modulation of <I>AbMAPK1</I> expression under pathogenic stress suggested its putative involvement in the immune defense mechanism.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A MAPK1 from disk abalone (AbMAPK1) was identified and characterized. </LI> <LI> Expression profile of abalone developmental stages was analyzed. </LI> <LI> The expression profile of healthy tissues of adult abalones was investigated. </LI> <LI> Transcriptional level of <I>AbMAPK1</I> was modulated by both viral and bacterial exposure. </LI> </UL> </P>

Molecular, structural, and functional comparison of N lobe and C lobe of the transferrin from rock bream, <i>Oplegnathus fasciatus,</i> with respect to its immune response

Perera, N.C.N.,Godahewa, G.I.,Hwang, Jee Youn,Kwon, Mun Gyeong,Hwang, Seong Don,Lee, Jehee Elsevier 2017 Fish & shellfish immunology Vol.68 No.-

<P><B>Abstract</B></P> <P>The iron-withholding strategy of innate immunity is an effective antimicrobial defense mechanism that combats microbial infection by depriving microorganisms of Fe<SUP>3+</SUP>, which is important for their growth and propagation. Transferrins (Tfs) are a group of iron-binding proteins that exert their antimicrobial function through Fe<SUP>3+</SUP> sequestration. The current study describes both structural and functional characteristics of a transferrin ortholog from rock bream <I>Oplegnathus fasciatus</I> (RbTf). The RbTf cDNA possesses an open reading frame (ORF) of 2079 bp encoding 693 amino acids. It has a molecular mass of approximately 74 kDa and an isoelectric point of 5.4. <I>In silico</I> analysis revealed that RbTf has two conserved domains: N-terminal domain and C-terminal domain. Pairwise homology analysis and phylogenetic analysis revealed that RbTf shared the highest identity (82.6%) with <I>Dicentrarchus labrax</I> Tf. According to the genomic analysis, RbTf possesses 17 exons and 16 introns, similar to the other orthologs. Here, we cloned the N terminal and C terminal domains of RbTf to evaluate their distinct functional features. Results obtained through the CAS (chrome azurol S) assay confirmed the iron-binding ability of the RbTf, and it was further determined that the iron-binding ability of rRbTfN was higher than that of rRbTfC. The antimicrobial functions of the rRbTfN and the rRbTfC were confirmed via the iron-dependent bacterial growth inhibition assay. Tissue distribution profiling revealed a ubiquitous expression with intense expression in the liver. Temporal assessment revealed that <I>RbTf</I> increased after stimulation of LPS, <I>Edwardsiella tarda,</I> and <I>Streptococcus iniae</I> post injection (p.i.). These findings demonstrated that RbTf is an important antimicrobial protein that can combat bacterial pathogens.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Transferrin was identified from rock bream (<I>RbTf</I>). </LI> <LI> N terminal and C terminal domains of RbTf was separately cloned and evaluated their distinct functional features. </LI> <LI> CAS (chrome azurol S) assay confirmed the iron-binding ability of the RbTf. </LI> <LI> Transcriptional level of <I>RbTf</I> was modulated by pathological stress. </LI> </UL> </P>

An ionic liquid incorporated gel polymer electrolyte for double layer capacitors

Perera, Kumudu S.,Prasadini, K.W.,Vidanapathirana, Kamal P. Techno-Press 2020 Advances in energy research Vol.7 No.1

Energy storage devices have received a keen interest throughout the world due to high power consumption. A large number of research activities are being conducted on electrochemical double layer capacitors (EDLCs) because of their high power density and higher energy density. In the present study, an EDLC was fabricated using natural graphite based electrodes and ionic liquid (IL) based gel polymer electrolyte (GPE). The IL based GPE was prepared using the IL, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (1E3MITF) with the polymer poly(vinyl chloride) (PVC) and the salt magnesium trifluoromethanesulfonate (Mg(CF₃SO₃)₂ - MgTF). GPE was characterized by electrochemical impedance spectroscopy (EIS), DC polarization test, linear sweep voltammetry (LSV) test and cyclic voltammetry (CV) test. The maximum room temperature conductivity of the sample was 1.64 × 10^-4 Scm^-1. The electrolyte was purely an ionic conductor and the anionic contribution was prominent. Fabricated EDLC was characterized by EIS, CV and galvanostatic charge discharge (GCD) tests. CV test of the EDLC exhibits a single electrode specific capacitance of 1.44 Fg^-1 initially and GCD test gives 0.83 Fg^-1 as initial single electrode specific discharge capacitance. Moreover, a good stability was observed for prolonged cycling and the device can be used for applications with further modifications.

NOX-VOC-O3 Sensitivity in Urban Environments of Sri Lanka

Perera G.B.S.,Manthilake M.M.I.D.,Sugathapala A.G.T.,Huy L.N.,Lee S.C. 한국대기환경학회 2019 Asian Journal of Atmospheric Environment (AJAE) Vol.13 No.1

Physical phenomenon of the relation among the ground level O3, NOX and VOC governed by complex nonlinear photochemistry in urban environments is explained in detail using the ambient pollutant concentration data of eleven cities in Sri Lanka. The time-series analysis was conducted using the 24-hour average ambient concentrations of PM10, NO2, CO, O3 and SO2 air pollutants obtained from fixed air pollution monitoring station located in Colombo since 2008. Further analysis was carried out from the mobile air pollution monitoring station for eleven cities. The hourly averaged ambient real time air quality data i.e. VOC, NO2, NO, O3 pollutants and the corresponding meteorological parameters were analyzed and presented in weekly results for the base year 2013, 2014 and 2015. It was identified that there exist two regimes of NOX-VOC-O3 sensitivity among these cities. Colombo, Kurunegala, Jaffna, Matara, Badulla, Pollonnaruwa, and Gampaha are the NOX-sensitive regime. While Rathnapura, Anuradhapura, Kandy and Nuwaraelliya are the VOC-sensitive regime. In the NOX-sensitive regime (with relatively low NOX and high VOC), O3 increases with the increasing NOX and slightly changes in response to the increasing VOC levels. In the NOX-saturated or VOC-sensitive regime, O3 decreases with increasing NOX level and increases with increasing VOC levels. In the immediate vicinity of very large emissions of NO, O3 concentrations are depressed through the process of NOX titration. Mathematical relationships were developed to calculate the steady state ozone concentration (O3ss) that gives the values for both NOX-sensitive regime and the VOC-sensitive regime. Establishment of these relationships are essential for Sri Lanka to develop the appropriate interventions for controlling O3 pollution in each city.

Molecular structure and immune-stimulated transcriptional modulation of the first teleostean IFP35 counterpart from rockfish (Sebastes schlegelii)

Perera, N.C.N.,Godahewa, G.I.,Nam, B.H.,Lee, J. Academic Press 2016 FISH AND SHELLFISH IMMUNOLOGY Vol.56 No.-

<P>Interferons (IFNs) and IFN-inducible proteins play numerous physiological roles, particularly in antiviral defense mechanisms of the innate immune response with the presence of pathogens. IFN-induced protein-35 kDa (IFP35) is induced by Type II IFN (IFN-gamma); it is a cytoplasmic protein that can be trans located to the nucleus via the stimulation of IFN. In this study, we report the complete molecular characterization of the IFP35 cDNA sequence from the black rockfish in an effort to understand its role in the immune response. The coding sequence of RfIFP35 encoded a putative peptide of 371 amino acids containing two characteristic Nmi/IFP 35 domains (NIDs), which are highly conserved among its counterparts. The protein showed a molecular mass of 42.2 kDa with a theoretical pI of 5.05 and was predicted to be unstable because of its high instability index (4937). Therefore, the protein-protein interaction is essential for its stability, which may be facilitated by the intrinsically disordered regions in this protein. According to cellular location prediction, the RflFP35 protein is cytosolic. Phylogenetic analysis showed that RfIFP35 was cladded within the fish counterparts. Tissue distribution profiling revealed a ubiquitous presence of the protein in all examined tissues, with highest expression in the blood followed by the spleen tissues. The expression of RfIFP35 during immune challenge with poly I:C and lipopolysaccharide treatments affirms its putative importance in the first-line host defense system. RfIFN-gamma mRNA was significantly expressed at 6 h p.i. in blood and 3 h p.i. in the spleen following treatment with different immune stimulants, and its expression was higher compared to that of RfIFP35 mRNA. Therefore, the modulation patterns of both RfIFP35 and RfIFN-gamma suggest that RfIFP35 may be induced by RfEN-gamma. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Two metalloenzymes from rockfish (<i>Sebastes schligellii</i>): Deciphering their potential involvement in redox homeostasis against oxidative stress

Perera, N.C.N.,Godahewa, G.I.,Nam, Bo-Hye,Park, Jung Youn,Lee, Jehee Elsevier 2018 FISH AND SHELLFISH IMMUNOLOGY Vol.80 No.-

<P>Disturbance in the balance between pro-oxidants and anti-oxidants result oxidative stress in aerobic organisms. However, oxidative stress can be inhibited by enzymatic and non-enzymatic defense mechanisms. Superoxide dismutases (SODs) are well-known scavengers of superoxide radicals, and they protect cells by detoxifying hazardous reactive oxygen species. Here, we have identified and characterized two different SODs, CuZnSOD and MnSOD, from black rockfish (RfCuZnSOD and RfMnSOD, respectively). In silica analysis revealed the well conserved molecular structures comprising all essential properties of CuZnSOD and MnSOD. Phylogenetic analysis revealed that both RfCuZnSOD and RfMnSOD cladded with their fish counterparts. The recombinant RfSOD proteins demonstrated their potential superoxide scavenging abilities through a xanthine oxidase assay. The optimum temperature and pH conditions for both rRfSODs were 25 degrees C and pH 8, respectively. Moreover, the potential peroxidation function of rRfCuZnSOD was observed in the presence of HCO3-. The highest peroxidation activity was observed at 100 mu g/mL of rRfCuZnSOD using the MTT cell viability assay and flow cytometry. The analogous tissue-specific expression profile indicated ubiquitous expression of both RfCuZnSOD and RfMnSOD in selected tissues of healthy juvenile rockfish. An immune challenge experiment illustrated the altered expression profiles of both RfCuZnSOD and RfMnSOD against lipopolysaccharide, Streptococcus iniae, and polyinosinic-polycytidylic acid (poly I:C). Collectively, these results strengthen the general understanding of the structural and functional characteristics of SODs within the host defense system.</P>

Collaborative consumption participation intentions: A cross-cultural study of Indian and U.S. consumers

Perera B. Yasanthi,Albinsson Pia A.,Nafees Lubna,Matthews Lucy 한국마케팅과학회 2023 마케팅과학연구 Vol.33 No.1

Worldwide, the emergence and growth of collaborative consumption (CC) based companies increasingly offer consumers new consumption opportunities and experiences. Given the importance of culture in shaping consumers’ behavior, to advance knowledge on similarities and differences in CC engagement, this research examines select motivating factors as antecedents to CC participation intention (CCPI) in the U.S. and India. Partial least squaresstructural equation modeling (PLS-SEM) is used to analyze consumer panel data to investigate the relationships between resource motivation, risk-propensity, trust, generosity, materialism and attitude as antecedents to consumers’ CCPI. Results indicate that in both countries, risk-propensity has a positive impact on materialism, trust is positively related to materialism and attitude, while generosity is negatively related to materialism and attitude. Individual country differences, and theoretical and practical implications are discussed.

Identification and characterization of a carboxypeptidase N1 from red lip mullet (<i>Liza haematocheila</i>); revealing its immune relevance

Perera, N.C.N.,Godahewa, G.I.,Jung, Sumi,Kim, Myoung-Jin,Nam, Bo-Hye,Lee, Jehee ACADEMIC PRESS LTD 2019 FISH AND SHELLFISH IMMUNOLOGY Vol.84 No.-

<P><B>Abstract</B></P> <P>Complement system orchestrates the innate and adaptive immunity <I>via</I> the activation, recruitment, and regulation of immune molecules to destroy pathogens. However, regulation of the complement is essential to avoid injuries to the autologous tissues. The present study unveils the characteristic features of an important complement component, anaphylatoxin inactivator from red lip mullet at its molecular and functional level. Mullet carboxypeptidase N1 (MuCPN1) cDNA sequence possessed an open reading frame of 1347 bp, which encoded a protein of 449 amino acids with a predicted molecular weight of 51 kDa. <I>In silico</I> analysis discovered two domains of PM14-Zn carboxypeptidase and a C-terminal domain of M14 N/E carboxypeptidase, two zinc-binding signature motifs, and an N-glycosylation site in the MuCPN1 sequence. Homology analysis revealed that most of the residues in the sequence are conserved among the other selected homologs. Phylogeny analysis showed that MuCPN1 closely cladded with the <I>Maylandia zebra</I> CPN1 and clustered together with the teleostean counterparts. A challenge experiment showed modulated expression of MuCPN1 upon polyinosinic:polycytidylic acid and <I>Lactococcus garviae</I> in head kidney, spleen, gill, and liver tissues. The highest upregulation of MuCPN1 was observed 24 h post infection against poly I:C in each tissue. Moreover, the highest relative expressions upon <I>L. garviae</I> challenge were observed at 24 h post infection in head kidney tissue and 48 h post infection in spleen, gill, and liver tissues. MuCPN1 transfected cells triggered a 2.2-fold increase of nitric oxide (NO) production upon LPS stimulation compared to the un-transfected controls suggesting that MuCPN1 is an active protease which releases arginine from complement C3a, C4a, and C5a. These results have driven certain way towards enhancing the understanding of immune role of MuCPN1 in the complement defense mechanism of red lip mullet.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Carboxypeptidase N1 complement component was identified from the red lip mullet. </LI> <LI> Ubiquitous expression of MuCPN1 was observed in healthy mullet tissues. </LI> <LI> Modulated transcriptions of MuCPN1 revealed the importance in the immune responses. </LI> <LI> MuCPN1 was enhanced the nitric oxide production at an inflammatory condition. </LI> </UL> </P>

The effect of switching costs on resistance to change in the use of software

Perera, Nipuna,Kim, Hee-Woong 한국경영정보학회 2007 한국경영정보학회 학술대회논문집 Vol.2007 No.-

People tend to resist changing their software even alternatives are better then the current one. This study examines the resistance to change in the use of software from the switching costs perspective based on status quo bias theory. For this study, we select Web Browsers as software. Based on the classification of switching costs into three groups (psychological, procedural, and loss), this study identifies six types of switching costs (uncertainty, commitment, learning, setup, lost performance, and sunk costs). This study tests the effects of six switching costs on user resistance to change based on the survey of 204 web browser users. The results indicate that lost performance costs and emotional costs have significant effects on user resistance to change. This research contributes towards understanding of switching costs and the effects on user resistance to change. This study also offers suggestions to software vendors for retaining their users and to organizations for managing user resistance in switching and adopting software.