Genomic characterization, expression analysis, and antimicrobial function of a glyrichin homologue from rock bream, Oplegnathus fasciatus

Kasthuri, S.R.,Wan, Q.,Umasuthan, N.,Bathige, S.D.N.K.,Lim, B.S.,Jung, H.B.,Lee, J.,Whang, I. Academic Press 2013 Fish & shellfish immunology Vol.35 No.5

Antimicrobial peptides are important innate effector molecules, playing a vital role in antimicrobial immunity in all species. Glyrichin is a transmembrane protein and an antibacterial peptide, exerting its functions against a wide range of pathogenic bacteria. In this study, cDNA and a BAC clone harboring the glyrichin gene were identified from rock bream and characterized. Genomic characterization showed that the OfGlyrichin gene exhibited a 3 exon-2 intron structure. OfGlyrichin is a 79-amino-acid protein with a transmembrane domain at <SUP>22</SUP>GFMMGFAVGMAAGAMFGTFSCLR<SUP>44</SUP>. Pairwise and multiple sequence alignments showed high identity and conservation with mammalian orthologues. Phylogenetic analysis showed a close relationship with fish species. Higher levels of OfGlyrichin transcripts were detected in the liver from healthy rock bream which were induced by immunogens like lipopolysaccharide, poly I:C, rock bream irido virus, Edwardsiella tarda and Streptococcus iniae. The synthetic peptide (pOf19) showed antibacterial activity against Escherichia coli, E. tarda, and S. iniae. Analysis of the bacterial morphological features after pOf19 peptide treatment showed breakage of the cell membrane, affirming that antibacterial function is accomplished through membrane lysis. The pOf19 peptide also showed antiviral activity against RBIV infection. The high conservation of the genomic structure and protein, together with the antimicrobial roles of OfGlyrichin, provide evidence for the evolutionary existence of this protein playing a vital role in innate immune defense in rock bream.

Two duplicated chicken-type lysozyme genes in disc abalone Haliotis discus discus: Molecular aspects in relevance to structure, genomic organization, mRNA expression and bacteriolytic function

Umasuthan, N.,Bathige, S.D.N.K.,Kasthuri, S.R.,Wan, Q.,Whang, I.,Lee, J. Academic Press 2013 FISH AND SHELLFISH IMMUNOLOGY Vol.35 No.2

Lysozymes are crucial antibacterial proteins that are associated with catalytic cleavage of peptidoglycan and subsequent bacteriolysis. The present study describes the identification of two lysozyme genes from disc abalone Haliotis discus discus and their characterization at sequence-, genomic-, transcriptional- and functional-levels. Two cDNAs and BAC clones bearing lysozyme genes were isolated from abalone transcriptome and BAC genomic libraries, respectively and sequences were determined. Corresponding deduced amino acid sequences harbored a chicken-type lysozyme (LysC) family profile and exhibited conserved characteristics of LysC family members including active residues (Glu and Asp) and GS(S/T)DYGIFQINS motif suggested that they are LysC counterparts in disc abalone and designated as abLysC1 and abLysC2. While abLysC1 represented the homolog recently reported in Ezo abalone [1], abLysC2 shared significant identity with LysC homologs. Unlike other vertebrate LysCs, coding sequence of abLysCs were distributed within five exons interrupted by four introns. Both abLysCs revealed a broader mRNA distribution with highest levels in mantle (abLysC1) and hepatopancreas (abLysC2) suggesting their likely main role in defense and digestion, respectively. Investigation of temporal transcriptional profiles post-LPS and -pathogen challenges revealed induced-responses of abLysCs in gills and hemocytes. The in vitro muramidase activity of purified recombinant (r) abLysCs proteins was evaluated, and findings indicated that they are active in acidic pH range (3.5-6.5) and over a broad temperature range (20-60 <SUP>o</SUP>C) and influenced by ionic strength. When the antibacterial spectra of (r)abLysCs were examined, they displayed differential activities against both Gram positive and Gram negative strains providing evidence for their involvement in bacteriolytic function in abalone physiology.

A bifunctional invertebrate-type lysozyme from the disk abalone, Haliotis discus discus: Genome organization, transcriptional profiling and biological activities of recombinant protein

Bathige, S.D.N.K.,Umasuthan, N.,Kasthuri, S.R.,Whang, I.,Lim, B.S.,Nam, B.H.,Lee, J. Pergamon Press ; Elsevier Science 2013 Developmental and comparative immunology Vol.41 No.2

Lysozyme is an important enzyme in the innate immune system that plays a vital role in fighting microbial infections. In the current study, we identified, cloned, and characterized a gene that encodes an invertebrate-type lysozyme from the disk abalone, Haliotis discus discus (abLysI). The full-length cDNA of abLysI consisted of 545bp with an open reading frame of 393bp that encodes 131 amino acids. The theoretical molecular mass of mature abLysI was 12.3kDa with an isoelectric point of 8.03. Conserved features in other homologs, such as catalytic sites for lytic activity (Glu<SUP>30</SUP> and Asp<SUP>41</SUP>), isopeptidase activity (His<SUP>107</SUP>), and ten cysteine residues were identified in abLysI. Genomic sequence analysis with respect to its cDNA showed that abLysI was organized into four exons interrupted by three introns. Several immune-related transcription factor binding sites were discovered in the putative promoter region. Homology and phylogeny analysis of abLysI depicted high identity and closer proximity, respectively, with an annelid i-type lysozyme from Hirudo medicinalis, and indicated that abLysI is a novel molluscan i-type lysozyme. Tissue-specific expressional studies revealed that abLysI is mainly transcribed in hepatopancreas followed by mantle. In addition, abLysI mRNA expression was induced following bacterial (Vibrio parahaemolyticus and Listeria monocytogenes) and viral (viral hemorrhagic septicemia virus) challenges. Recombinantly expressed abLysI [(r)abLysI] demonstrated strong lytic activity against Micrococcus lysodeikticus, isopeptidase activity, and antibacterial activity against several Gram-positive and Gram-negative bacteria. Moreover, (r)abLysI showed optimum lytic activity at pH 4.0 and 60<SUP>o</SUP>C, while exhibiting optimum isopeptidase activity at pH 7.0. Taken together, these results indicate that abLysI is potentially involved in immune responses of the disk abalone to protect it from invaders.

Classical Tamil Speech Enhancement with Modified Threshold Function using Wavelets

Indra. J,Kasthuri. N,Navaneetha Krishnan. S 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.6

Speech enhancement is a challenging problem due to the diversity of noise sources and their effects in different applications. The goal of speech enhancement is to improve the quality and intelligibility of speech by reducing noise. Many research works in speech enhancement have been accomplished in English and other European Languages. There has been limited or no such works or efforts in the past in the context of Tamil speech enhancement in the literature. The aim of the proposed method is to reduce the background noise present in the Tamil speech signal by using wavelets. New modified thresholding function is introduced. The proposed method is evaluated on several speakers and under various noise conditions including White Gaussian noise, Babble noise and Car noise. The Signal to Noise Ratio (SNR), Mean Square Error (MSE) and Mean Opinion Score (MOS) results show that the proposed thresholding function improves the speech enhancement compared to the conventional hard and soft thresholding methods.

Feature Extraction and Classification of EEG Signal Using Multilayer Perceptron

Mouleeshuwarapprabu R.,Kasthuri N. 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

Electroencephalography (EEG) is a typical tool utilized for the discovery of epileptic seizures. Notwithstanding, long-term EEG, visual investigation of records is described by its subjectivity, time-consuming procedure, and misdiagnosis. Different types of seizure detection algorithms are used to solve the problems but these methods have a high false classification ratio. Therefore this work introduces a novel automatic seizure detection mechanism to reduce the false classification ratio. The proposed strategies suggest that users choose the appropriate one for a given classification problem. The wavelet transform is based on the principle of describing the temporal evolution of a signal across different time scales by providing information about the local regularity. Multi-Model Features must be extracted from individual sources of data by constructing a signal that is appropriate for the type of data. The extraction of features from one source is independent of the extraction of features from an ECG Signal. Therefore, the proposed method for detecting automatic epilepsy identification may be considered a significant option compared to the traditional strategies, which can reduce the overload of visual analysis and accelerate the detection of seizures.

Exploring the Connectome: Petascale Volume Visualization of Microscopy Data Streams

Beyer, J.,Hadwiger, M.,Al-Awami, A.,Won-Ki Jeong,Kasthuri, N.,Lichtman, J. W.,Pfister, H. IEEE 2013 IEEE computer graphics and applications Vol.33 No.4

<P>Recent advances in high-resolution microscopy let neuroscientists acquire neural-tissue volume data of extremely large sizes. However, the tremendous resolution and the high complexity of neural structures present big challenges to storage, processing, and visualization at interactive rates. A proposed system provides interactive exploration of petascale (petavoxel) volumes resulting from high-throughput electron microscopy data streams. The system can concurrently handle multiple volumes and can support the simultaneous visualization of high-resolution voxel segmentation data. Its visualization-driven design restricts most computations to a small subset of the data. It employs a multiresolution virtual-memory architecture for better scalability than previous approaches and for handling incomplete data. Researchers have employed it for a 1-teravoxel mouse cortex volume, of which several hundred axons and dendrites as well as synapses have been segmented and labeled.</P>