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( Sangyeop Shin ),( D. C. M. Kulatunga ),( S. H. S. Dananjaya ),( Chamilani Nikapitiya ),( Jehee Lee ),( Mahanama De Zoysa ) 한국균학회 2017 Mycobiology Vol.45 No.4
Saprolegniasis is one of the most devastating oomycete diseases in freshwater fish which is caused by species in the genus Saprolegnia including Saprolegnia parasitica. In this study, we isolated the strain of S. parasitica from diseased rainbow trout in Korea. Morphological and molecular based identification confirmed that isolated oomycete belongs to the member of S. parasitica, supported by its typical features including cotton-like mycelium, zoospores and phylogenetic analysis with internal transcribed spacer region. Pathogenicity of isolated S. parasitica was developed in embryo, juvenile, and adult zebrafish as a disease model. Host-pathogen interaction in adult zebrafish was investigated at transcriptional level. Upon infection with S. parasitica, pathogen/antigen recognition and signaling (TLR2, TLR4b, TLR5b, NOD1, and major histocompatibility complex class I), pro/anti-inflammatory cytokines (interleukin [IL]-1β, tumor necrosis factor α, IL-6, IL-8, interferon γ, IL-12, and IL-10), matrix metalloproteinase (MMP9 and MMP13), cell surface molecules (CD8<sup>+</sup> and CD4<sup>+</sup>) and antioxidant enzymes (superoxide dismutase, catalase) related genes were differentially modulated at 3- and 12-hr post infection. As an anti-Saprolegnia agent, plant based lawsone was applied to investigate on the susceptibility of S. parasitica showing the minimum inhibitory concentration and percentage inhibition of radial growth as 200 μg/mL and 31.8%, respectively. Moreover, natural lawsone changed the membrane permeability of S. parasitica mycelium and caused irreversible damage and disintegration to the cellular membranes of S. parasitica. Transcriptional responses of the genes of S. parasitica mycelium exposed to lawsone were altered, indicating that lawsone could be a potential anti-S. parasitica agent for controlling S. parasitica infection.
Kulatunga, D.C.M.,Dananjaya, S.H.S.,Nikapitiya, Chamilani,Godahewa, G.I.,Cho, Jongki,Kim, Cheol-Hee,Lee, Jehee,De Zoysa, Mahanama Elsevier 2019 Fish & Shellfish Immunology Vol.84 No.-
<P><B>Abstract</B></P> <P>Proteins with dithiol-disulfide oxidoreductase catalytic domain are well known for their capacity in the cellular redox homeostasis. In this study, we characterized the zebrafish thioredoxin domain containing 12 (Zf<I>txndc12</I>) gene, analyzed the transcriptional responses and studied the functional properties of its recombinant protein. Full-length cDNA of Zf<I>txndc12</I> consists 519 bp coding region encoding 172 amino acids (AA) including the signal peptide. Highly consensus active motif (<SUP>65</SUP>WCGAC<SUP>69</SUP>) and probable ER retrieval motif (<SUP>169</SUP>GDEL<SUP>172</SUP>) were identified. Ubiquitous expression of Zf<I>txndc1</I>2 mRNA was observed from one cell to juvenile stage as well as different organs of adult zebrafish. Moreover, whole mount <I>in situ</I> hybridization (WISH) results showed a higher expression of Zf<I>txndc12</I> in primordial gills, central nerves system and eye. The tissue specific expression analysis (by qRT-PCR) also showed the highest expression in gills followed by brain in adult zebrafish. In larvae, up-regulated Zf<I>txndc1</I>2 mRNA expression upon exposure to H<SUB>2</SUB>O<SUB>2,</SUB> <I>Edwardsiella tarda</I> and <I>Saprolegnia parasitica</I> suggests that it may involve in both stress and immune responses. Moreover, transcriptional expression of Zf<I>txndc12</I> was up-regulated upon <I>Streptococcus iniae</I> challenge in gills of adult zebrafish<I>.</I> The recombinant ZfTxndc12 (rZfTxndc12) was overexpressed, purified and tested for its biological activities. Results revealed that rZfTxndc12 is able to reduce the DNA damage and detoxify the H<SUB>2</SUB>O<SUB>2</SUB> toxicity in concentration dependent manner. Overall results suggest that Zf<I>txndc12</I> is important antioxidant and immune functional member of the host defense system in zebrafish.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Txndc12 is important for oxidative stress defense and redox regulation. </LI> <LI> Constitutive expression of Zftxndc12 is ubiquitous in embryonic developmental stages and adult zebrafish. </LI> <LI> Immune challenge and oxidative stress induce the Zftxndc12 transcription in zebrafish larvae and adult's gills. </LI> <LI> >Recombinant Zftxndc12 shows <I>in vitro</I> ROS scavenging and cytoprotective activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Godahewa, G.I.,Kim, Yucheol,Dananjaya, S.H.S.,Jayasooriya, R.G.P.T.,Noh, Jae Koo,Lee, Jehee,De Zoysa, Mahanama Elsevier 2015 Fish & shellfish immunology Vol.43 No.1
<P><B>Abstract</B></P> <P>Pathogenic infections and environmental factors cause a variety of stresses in fish including oxidative stress by rapid elevation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Transcriptional activation and expression of antioxidant enzymes are essential for reducing the oxidative stress. In this study, we present the molecular characterization, immune responses and ROS scavenging activity of mitochondrial peroxiredoxin 3 from <I>Oplegnathus fasciatus</I> (<I>RbPrx3</I>). Coding sequence (CDS) of <I>RbPrx3</I> contains 248 amino acids polypeptide which consists of highly conserved peroxiredoxin super family domain and two cysteine residues. Pairwise sequence comparison revealed that <I>RbPrx3</I> has the greatest identity (94.8%) to <I>Sparus aurata</I> Prx3. Transcriptional analysis of <I>RbPrx3</I> indicated the ubiquitously expressed mRNA in wide array of organs showing the highest expression in the liver of rock bream. Upon immune challenge of <I>Edwardsiella tarda</I>, <I>Streptococcus iniae</I>, rock bream iridovirus (RBIV) and lipopolysaccharide (LPS), <I>RbPrx3</I> mRNA level was up-regulated in immunocompetent liver tissues compared to unchallenged fish. Purified recombinant RbPrx3 treated THP-1 cells showed higher survival rate against H<SUB>2</SUB>O<SUB>2</SUB> induced oxidative stress and significantly reduced the level of intracellular ROS. Overall results from our study suggest that RbPrx3 may be involved in broader functions such as regulating oxidative stresses by scavenging ROS and activating immune responses in rock bream.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PRx3 is important for antioxidant defense and redox signaling. </LI> <LI> RbPrx3 is categorized into 2-Cys Prx. </LI> <LI> Constitutive expression of RbPrx3 is shown in wider array of rock bream tissues. </LI> <LI> Immune challenge activates the transcription of Prx3 in liver. </LI> <LI> Recombinant Prx6 can protect cells from oxidative stress by reducing H<SUB>2</SUB>O<SUB>2</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Dananjaya S.H.S.,GODAHEWAGELSHAN IMARSHANA,이영득,조종기,이제희,디조이사마하나마 한국임상수의학회 2014 한국임상수의학회지 Vol.31 No.6
Recently nano particles have proven for wide array of bioactive properties. In the present study, antibacterialproperties of chitosan silver nano composites (CAgNCs) were investigated against fish pathogenic Edwardsiella tarda. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs against E. tarda were 25 μg/mL and 125 μg/mL, respectively. The field emission scanning electron microscope (FE-SEM) imageof CAgNCs treated E. tarda showed the strongly damaged bacteria cells than non-treated bacteria. Furthermore,treatment of CAgNCs induced the level of intracellular reactive oxygen species (ROS) in E. tarda cells in concentrationand time dependent manner suggesting that it may generate oxidative stress leading to bacterial cell death. In addition,MTT assay results showed that the lowest cell viability at 100 μg/mL of CAgNCs treated E. tarda. Overall resultsof this study suggest that CAgNCs is a potential antibacterial agent to control pathogenic bacteria.