• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.462-466
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• 2001

To understand molecular mechanisms of mouse mammary gland involution, clones were isolated by differential screening of a cDNA library. Partial sequences of a clone showed 100% identity to cDNA sequences of mouse lysozyme P gene. Northern analysis was performed to examine expression levels of lysozyme mRNA in mammary gland at several physiological states. Expression of lysozyme gene was induced at involution day 5 compared with lactating stage. High levels of lysozyme mRNA were also detected at virgin tissues. Two types of separate genes, P and M lysozyme, have been known in mouse, and we found that both lysozyme P and M genes were expressed in mammary tissues by reverse transcriptase-polymerase chain reaction. The lysozyme enzyme activity determined by lysoplate assay was also higher in involuted mammary tissues compared with lactating tissues, showing a similar trend to its mRNA levels. Lysozyme is an antimicrobial protein and involved in host defense mechanism. The increase in lysozyme gene expression may help to prevent microbial infection during mammary gland involution at which stage the residual milk in the mammary gland provides good nutritional sources for microbial growth.

• Animal cells and systems
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• v.13 no.3
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• pp.345-350
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• 2009

We have isolated and characterized a new insect chicken type (c-type) lysozyme gene from the common cutworm, Spodoptera litura. The full-length cDNA of Spodoptera lysozyme is cloned by rapid amplification of cDNA ends PCR (RACE-PCR). The isolated cDNA consists of 1039 bp including the coding region for a 142-amino acid residue polypeptide, which included a signal peptide of 21-amino acid residue and a mature protein of 121-amino acid residue. The predicted molecular weight of mature lysozyme and its theoretical isoelectric point from amino acid composition is 13964.8 Da and 9.05, respectively. The deduced amino acid sequence of Spodoptera lysozyme gene shows the highest similarity (96.7%) to Spodoptera exigua lysozyme among other lepidopteran species. Amino acid sequence comparison with other the c-type lysozymes, Spodoptera lysozyme has the completely conserved $Glu^{32}$ and $Asp^{50}$ of the active site and eight Cys residues are completely conserved in the same position as that of other lepidopteran lysozymes.

• Animal cells and systems
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• v.16 no.6
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• pp.455-461
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• 2012

Amongst the various antimicrobial peptides, lysozyme plays a central role in initiating and maintaining the antibacterial defense response of insect. Here we propose the biosynthesis and refolding of recombinant lysozyme in Escherichia coli expressed in inclusion body form. The Agrius lysozyme gene was amplified using gene specific primers and then ligated into the pGEX-4T-1 vector, which contained the glutathione S-transferase (GST) gene as a fusion partner. A recombinant lysozyme was expressed in E. coli Rosetta cells using a pGEX-4T-1 expression vector, and the fusion protein was induced by ioporpyl-${\beta}$-D-thiogalactopyranoside (IPTG). The recombinant protein produced as an inclusion body was resolubilized in solubilization buffer, and the resultant solution was dialyzed in refolding buffer. After thrombin cleavage, the recombinant lysozyme was purified by ion exchange chromatography and reverse phase chromatography. The recombinant lysozyme was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoreactivity against the anti-Agrius lysozyme was observed by western blot analysis of this protein. The recombinant lysozyme displayed antibacterial activity against Bacillus megaterium and Micrococcus luteus, which was confirmed by the inhibition zone assay.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.12
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• pp.1774-1783
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• 2015

Milk lysozyme is the ubiquitous enzyme in milk of mammals. In this study, the cDNA sequence of a new chicken-type (c-type) milk lysozyme gene (YML), was cloned from yak mammary gland tissue. A 444 bp open reading frames, which encodes 148 amino acids (16.54 kDa) with a signal peptide of 18 amino acids, was sequenced. Further analysis indicated that the nucleic acid and amino acid sequences identities between yak and cow milk lysozyme were 89.04% and 80.41%, respectively. Recombinant yak milk lysozyme (rYML) was produced by Escherichia coli BL21 and Pichia pastoris X33. The highest lysozyme activity was detected for heterologous protein rYML5 (M = 1,864.24 U/mg, SD = 25.75) which was expressed in P. pastoris with expression vector $pPICZ{\alpha}A$ and it clearly inhibited growth of Staphylococcus aureus. Result of the YML gene expression using quantitative polymerase chain reaction showed that the YML gene was up-regulated to maximum at 30 day postpartum, that is, comparatively high YML can be found in initial milk production. The phylogenetic tree indicated that the amino acid sequence was similar to cow kidney lysozyme, which implied that the YML may have diverged from a different ancestor gene such as cow mammary glands. In our study, we suggest that YML be a new c-type lysozyme expressed in yak mammary glands that plays a role as host immunity.

• Animal cells and systems
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• v.12 no.3
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• pp.149-155
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• 2008

We have isolated and characterized Agrius convolvuli cDNA encoding a c-type lysozyme. The cDNA sequence encodes a processed protein of 139 amino acid residues with 19 amino acid residues amino-terminal signal sequence and 120 amino acid residues mature sequence. The amino acid residues responsible for the catalytic activity and the binding of the substrate are conserved. Agrius lysozyme has a high identity to Manduca sexta. Recombinant A. convolvuli lysozyme was expressed in Escherichia coli BL21(DE3) pLysS cells for pGEX 4T-1 expression vector. Their optimal conditions for the fusion protein expression and purification were screened. Lysozyme gene amplified with primers ACLyz BamHI and ACLyz XhoI was ligated into the pGEX 4T-1 vector, which contained the glutathione S-transferase(GST) gene for fusion partner. The fusion protein was induced by IPTG and identified by SDS-PAGE analysis. Molecular weight of the fusion protein was estimated to be about 45 kDa. Recombinant lysozyme, fused to GST, was purified by glutathion-Sepharose 4B affinity chromatography. Western blot analysis of this protein revealed an immunoreactivity with the anti-Agrius lysozyme.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.138-144
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• 1995

The cDNA, encoding human lysozyme (HLY) which was isolated from a human placenta cDNA library, has been well characterized (Yoshimura et al., 1988). Based on the communication, we have prepared an artificial HLY gene from chemically synthesized 38-oligomer with high codon usage in Saccharomyces cerevisiae. For directing the synthesis and secretion of HLY in S. cerevisiae, an expression vector, pHKl was constructed by inserting the HLY gene, containing a synthetic HLY secretion signal sequence, between the yeast GAP promoter and PH05 terminator. From a lysoplate assay, we have confirmed an yeast transformant harboring a pHK1 which makes a clearing zone on the overlayed Micrococcus luteus. This result means a chemically synthesized HLY gene which was normally expressed and secreted in yeast.

• Biomedical Science Letters
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• v.24 no.2
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• pp.116-124
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• 2018

Lysozyme is known as a key substance of the innate immunity and have antibacterial effect in the mucosal tissues, especially middle ear. Aquaporin (AQP) functions as water movement in the tissue and has been expected to be participated in the inflammatory responses. In the present study, we investigated to reveal association of lysozymes and AQPs in otitis media. The gene expression of lysozyme genes, homo sapiens lysozyme (hLYZ), homo sapiens lysozyme M (hLYZ M), and homo sapiens lysozyme G like-2 (hLYGH), and AQP genes (AQP 0 - AQP 12) were measured from postauricular skin, mastoid mucosa, inflamed mastoid mucosa, and middle ear mucosa. The hLYZ, hLYZ M and hLYGH gene were expressed in mastoid mucosa, inflamed mastoid mucosa, middle ear mucosa. Of AQP genes, all AQP gene except AQP 3 gene were expressed in the tissue of middle ear. Among them, AQP 4, AQP 8, AQP 9, AQP 10, AQP 11 and AQP 12 were highly expressed in the inflamed mastoid mucosa and normal mastoid mucosa (P<0.001). Interestingly, expression levels of AQP 4, AQP 9, and AQP 12 gene were significantly higher in the inflamed mastoid mucosa compared to normal middle ear mucosa (P<0.05). These results suggest that lysozyme and AQPs could be associated with inflammatory response in the middle ear.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.993-999
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• 2010

Serum lysozyme gene is one of the important genes influencing the immune system as its product can cause lysis of bacterial cell wall by cleaving the peptidoglycan layer. The present investigation on the serum lysozyme gene of Indian riverine buffalo was undertaken with the objectives to identify and characterize single nucleotide polymorphic patterns by PCR-SSCP method as well as to study the effect of different genotypes on serum lysozyme activity and somatic cell count. A total of 280 animals comprising four different famous bubaline breeds (Murrah, Mehsana, Surti and Bhadawari), spread over six different farms across the country were used for this study. A 276 bp (partial intron 2, complete exon 3 and partial intron 3) fragment of lysozyme gene was screened for polymorphism using the SSCP technique. Four genotypes namely AA, AB, BC and AC were observed, out of which BC genotype was found to be the most frequent. Among these three alleles, C allele (0.38) was most prevalent in these populations. Various SSCP allelic variants were cloned for sequencing and sequences were submitted to NCBI Genbank. From the alignment of the nucleotide sequences of various allelic variants, it was found that there were differences in 12 positions among the alleles, out of which maximum variation (at 8 places) was found in the intronic region. The allele A was closer to allele-C than allele-B. Allele B was phylogenetically equidistant from both of the other alleles. Mean lysozyme activity determined in serum samples of different animals of Murrah buffalo was $27.35{\pm}2.42\;{\mu}g$ per ml of serum, whereas the mean somatic cell count was $1.25{\pm}0.13{\times}10^5$ cells per ml of milk. The SSCP pattern-wise effects of various genotypes on lysozyme activity and SCC were analyzed. Although the mean values were apparently different in various genotypes, these differences were statistically non-significant. It can be concluded that the riverine buffaloes are sufficiently polymorphic with respect to serum lysozyme gene. The absence of AA genotype in Bhadawari breed of buffalo can be considered as a marker for breed characterization. The difference of four nucleotides in exon-3 indicates high selection pressure on the gene.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.83-91
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• 2004

Recently phage K11 lysozyme was cloned and characterized in our lab. The K11 lysozyme was identified to have dual functions. It not only cuts a peptidoglycan bond in bacterial cell wall but also acts as an inhibitor of K11 RNA polymerase. It has been known that the T7 lysozyme binds specifically to T7 RNA polymerase and inhibits transcription. The dual activities of K11 lysozyme are atreeable to the case of T7 phage lysozyme and RNA polymerare. In order to identify the binding magnitude of K11 lysozyme with K11 RNA polymerase, yeast two-hybrid system was used. K11 phage lysozyme gene was introduced into pLexA plasmid and used as a prey. Also, K11 phage RNA polymerase gene was introduced into pJG4-5 and used as a bait. The binding between K11 lysozyme and K11 RNA polymerase was demonstrated by expression of reporter genes such as lacZ and leu2.

• BMB Reports
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• v.31 no.4
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• pp.413-417
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• 1998

Transgenic mice containing a bovine ${\beta}-Casein/Human$ lysozyme fusion gene (pBZ) were generated in order to produce human lysozyme in their milk. The expression vector was a quadripartite fusion consisting of a 2 kb upstream DNA of the bovine ${\beta}-casein$ gene, human lysozyme gene, intron II of the rabbit ${\beta}-globin$ gene, and the polyadenylation/termination signals of SV40 DNA. Fertilized mouse zygotes were microinjected with pBZ, then transferred into the oviduct of foster mothers. Out of 20 mice born, 11 survived until postweaning and three were identified as positivetransgenic by Southern blot analysis (one male and two females). The founder mice were mated to BCFl mice to produce transgenic progeny. It was confirmed by RT-PCR and Northern blot analyses that the transgene was specifically expressed in the mammary gland of the founder mice. Furthermore, the artificial introns within the transgenic RNA was proven to be correctly spliced out as judged by RT-PCR analysis. These results indicated that transgenic mice generated in this study properly expressed the human lysozyme RNA in their mammary gland.