• Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.188-203
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• 2023

Lysozymes are well-known antibacterial enzymes that mainly target the peptidoglycan layer of the bacterial cell wall. Animal lysozymes are mainly categorized as g-type, c-type, and i-type based on protein sequence and structural differences. In this study, c-type (AcLysC) and g-like-type (AcLysG-like) lysozymes from Amphiprion clarkii were characterized in silico via expressional and functional approaches. According to in silico analysis, open reading frames of AcLysC and AcLysG-like were 429 bp and 570 bp, respectively, encoding the corresponding polypeptide chains with 142 and 189 amino acids. Elevated expression levels of AcLysC and AcLysG-like were observed in the liver and the heart tissues, respectively, as evidenced by quantitative real-time polymerase chain reaction assays. AcLysC and AcLysG-like transcript levels were upregulated in gills, head kidney, and blood cells following experimental immune stimulation. Recombinant AcLysC exhibited potent lytic activity against Vibrio anguillarum, whereas recombinant AcLysG-like showed remarkable antibacterial activity against Vibrio harveyi and Streptococcus parauberis, which was further evidenced by scanning electron microscopic imaging of destructed bacterial cell walls. The findings of this study collectively suggest the potential roles of AcLysC and AcLysG-like in host immune defense.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.36-40
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• 1998

This experiment was carried out in order to evaluate the immunomodulatory activity of levamisole (LMS) in 5. fgrjn challenged eels with different treatment regimens: 7-day LMS treatment before the challenge, 7-day LMS treatment started simultaneously with the challenge, 14-day treatment before and after the challenge. The antibacterial effect was activated in all treated groups, with the best being obtained in the simultaneously treated group. LMS stimulated the defense mechanisms of the eel as demonstrated by increase in the level of total protein, albumin, trypsin inhibitor capacity, lysozyme activity, antibody titers antibacterial activity and survival rate. These results suggest that antibacterial effects of LMS was achieved by not only non-specific immune response but also specific one in eel.

• Journal of fish pathology
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• v.32 no.1
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• pp.9-20
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• 2019

The study investigated the dietary effects of medicinal herbs extract and multiple probiotics mixture on the growth performance, innate immune response and antibacterial activity of nile tilapia Oreochromis niloticus. Tilapia were divided in four groups. The first is a fish group fed a basal diet added with 40% medicinal herbs extract (MHE). The second is a fish group fed a basal diet supplied with $2{\times}10^8CFU/g$ of 2 Bacillus sp, 2 Lactobacillus sp and 2 Yeast sp, respectively (PB). The third group was fed with a mixture of probiotics (2 Bacillus sp, 2 Lactobacillus sp and 2 Yeast sp) with the medicinal herbs extract added in basal diet (MHE+PB). The fourth group was fed only a basal diet (C). In a non-specific immune parameters analysis, respiratory burst activity, lysozyme activity, phagocytic activity (PA), alternative complement pathway activity ($ACH_{50}$) and superoxide dismutase (SOD) activity were significantly (p<0.05) increased in the group MHE+PB compared to other groups. Both PB and MHE groups showed a significant (p<0.05) increase in respiratory burst activity, lysozyme activity compared to the control C group, whereas no significant differences were observed in PA, $ACH_{50}$ and SOD activity compared to the control group. In challenging test, fish were administered with Edwardsiella tarda (E. tarda) on 30 days after feeding with each experimental diet and viable E. tarda cell reduction was checked over 21 days post injection. MHE+PB group showed a significantly (p<0.05) reduced E. tarda cells compared to other groups. No significant antibacterial difference (p>0.05) was observed between PB and MHE only treated group. Compared to the control, a significant antibacterial difference (p<0.05) appeared in PB but not in MHE (p>0.05). The results suggest that the probiotics and MHE mixture could be utilized as an alternative to antibiotics in the control of fish diseases caused by E. tarda.

• The Journal of the Korean Society for Microbiology
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• v.12 no.1
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• pp.19-32
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• 1977

The specificity of the N- and C-terminal antigenic determinant($P_{17}$: sequence $Lys^1-{cys-}^6-Asn^{27},\;{Trp^{12}}_2-Cys^{127}-Leu^{129}$) of hen egg-white lysozyme(HL) was studied in more detail. In a Scatchard plot of the binding of $^{14}C$-acetyl HL with guinea pig purified anti-$P_{17}$ antibody experimental values bent sharply aear r=1. This suggests of two antibody populations with different affinities for HL or possible steric hindrance in the binding of a second HL molecule to the second binding site of the antibody molecule. The antigenic activities of various peptides were tested by measuring their inhibition of the binding of $^{14}C-acetyl-P_{17}$ with the antibody, Only $P_{17}$ and $P_{17}t$(sequence $Lys^1-cys^6-Homoser^{12},\;Trp^{123}-Cys^{127}-Leu^{128})$) were inhibitory, with $K_1$ values of $2.0{\times}10^4$ and $8.1{\times}10^3$, respectively. These results indicate that the direct binding site of $P_{17}$ to anti-$P_{17}$ antibody may be located in the terminal portion of $P_{17}$ (sequence $Lys^1-Cys^6-Homoser^{12},\;Trp^{123}-Cys^{127}-Leu^{129})$) while the rest of $P_{17}$ may be important in maintaining the conformation of this determinant. The single disulphide bond involved in this determinant is essential for manifestation of immunological activity.

• Journal of fish pathology
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• v.27 no.1
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• pp.47-56
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• 2014

Propolis is a beehive product with a very complex chemical composition, widely used in folk medicine because of its several therapeutic activities. This study was conducted to measure the efficacy of propolis on non-specific defense reactions, specific immune response, and protection levels against pathogen challenge with Streptococcus iniae. in vitro and in vivo. In vitro, the phagocytic activity and NBT assay of peripheral blood leukocytes (PBL) were evaluated in a various propolis extractsconcentrations (0, 10, 50, 100, 150, 250 and $500{\mu}g/ml$). The optimal concentration showing activation of propolis extracts was determined to $100{\mu}g/ml$. In vivo, they were divided into four groups (PBS, propoli extractss, vaccine, propolis extracts + vaccine) in vivo. Fish were received i.p. injection of either PBS or propolis extracts, and in the presence or absence of formalin inactivated S. iniae ($1{\times}10^8$ CFU/fish), respectively. The level of haematocrit is not affected among experimental groups. The phagocytic activity and the NBT reduction activities of head kidney phagocyte were markedly (p<0.05)augmented in the propolis extracts groups than in the PBS-control group, respectively. The level of serum lysozyme activity was significantly (p<0.05) increased in the propolis extracts treated groups than in the PBS-control group. The agglutinin titer was significantly (p<0.05) enhanced in the vaccine+propolis extracts group than in the vaccine group, but there was no difference between PBS-control and propolis treated group. The results of the present study suggest that propolis extracts seems to be a promising compounds of non-specific immune stimulator, also being able to use a good adjuvant.

• Journal of fish pathology
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• v.15 no.1
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• pp.25-35
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• 2002

Effects of medicinal herb extract on nonspecific immune responses, hematology and disease resistance against Edwardsiella tarda in olive flounder, Paralichthys olivaceus were evaluated. Wormwood, Artemisia asiatica NAKAI and barrenwort, Epimedium koreanum NAKAI were mixed at a ratio of 7 : 3 (w/w) for 2-herbs extract and wormwood, barrenwort, Korean forsythia, Forsythia koreana NAKAI, chrysanthemum, Chrysanthemum zawadskii var. latilobum KITAMURA, peppermint, Mentha arvensis L. var, piperascens MALINV., great burnet, Snaguisorba afficinalis L., Lizard tail. Saururus chinensis BAILL., mulberry, Morus alba L., and star anise, Illicium varum HOOK, f, at the same weight for 9-herbs extract. Two-herbs of 9-herbs extract were prepared by heating after adding 10㎖ of distilled water per g of the herb mixtures. Fish (10.3$\pm$2.5g) were fed the experimental diets supplemented with the 2-herbs or 9-herbs extract at the different concentrations of 0%, 0.1%, 0.5% and 1% per kg diet for 12 weeks. Lysozyme and bactericidal activities of serum, and hematological characteristics were examined during experimental period. After feeding test period, all experimental groups were challenged with E. tarda. Lysozyme activity from the fish fed the diet supplemented with 0.1% or 0.5% of 2-herbs extract was significantly higher than the control. But there was no difference both in bactericidal activity and hematology among each group. Sixty seven % of relative percent survival values (RPS) in the group fed the diet supplemented with 0.1% of 2-herbs was higher than the other group and the control. These results suggest that supplenmentation of 0.1% of 2-herbs extract to a commercial diet may enhance disease resistance in olive flounder. Although both 0.1% and 0.5% 9-herbs extract did not improve non-specific immune reponses, they could enhance disease resistance of 53% RPS, respectively.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.47-54
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• 1990

In order to investigate physiological characteristics of fusants by interspecific protoplast fusion of the genus Cellulomonas, protoplasts of Cellulomonas flavigena NCIB 12901 and Cellulomonas bibula NCIB 8142 were fused and cell wall regenerated. To give gene maker, C. bibula was treated with 500 ug/ml NTG for 1 hr and arginine requiring auxotrophic mutants were isolated. Protoplasts of the genus Cellulomonas were obtained by treatment with $600{\mu}{\textrm{g}}$/ml lysozyme, and 0.5M sorbitol was optimal for osmotic stabilizer on protoplast fromation. Protoplast fusion was enhanced by 40% PEG)M.W.6,000) containing 25 mM $CaCl_{2}$ at $30^{\circ}C$ for 30 min and fusion frequency between C. bibula and C. flavigena was $5\times 10^{-4}$. Processes of protoplast formation, cell wall regeneration and protoplast fusion were obsdrved by scanning electron microscope. By comparing enzyme activities of cellulase, exocellobiohydrolase, .betha.-glucosidase of the parent strains of Cellulomonas with those of thier mutants and fusants, fusants with increased enzyme activity were obtained. By the studies on nutritional requirement, antibiotic resistance, cellulolytic enzyme activities, type of peptidoglycan and motility of two mutants and fusants, fusants were proved to be recombinant of both mutant strains.

• Journal of fish pathology
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• v.21 no.3
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• pp.219-228
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• 2008

The effects of dietary yeast β-glucan administration on growth, nonspecific immune responses, serum lysozyme, skin mucous lysozyme, NBT (nitroblue tetrazolium) reduction by phagocytes, and disease resistance against Edwardsiella tarda in Japanese eel, Anguilla japonica were evaluated. Fish were fed the diets supplemented with 0%, 0.1% and 0.5% of yeast β-glucan to a commercial diet for 6 weeks. The body weight gain from the fish fed on the 0.5% supplemented diet for 6 weeks was significantly higher than the control. Both serum and skin mucous lysozyme were significantly higher in the all experimental groups except 2 weeks of 0.5% group. The bactericidal activity of serum was slightly increased at 6 weeks. Also, The intracellular superoxide anion production of kidney phagocytes was significantly higher in the all experimental groups. The diet supplemented with 0.1% were also found to raise the relative percent survival (RPS) of Japanese eel after an artificial challenge with 1×107 cells of Edwardsiella tarda per fish. The results suggested the potential of yeast β-glucan to activate some innate immune responses and to improve the growth in Japanese eel.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1360-1367
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• 2014

Triplicate groups of fed and starved olive flounder, Paralichthys olivaceus (body weight: $119.8{\pm}17.46$ g), were examined over 42 days for physiological changes using hematological, biochemical, and non-specific immune parameters. No significant differences in concentrations of blood hemoglobin and hematocrit and plasma levels of total cholesterol, aspartate aminotransferase, alanine aminotransferase, glucose, and cortisol were detected between fed and starved groups at any sampling time throughout the experiment. In contrast, plasma total protein concentrations were significantly lower in starved fish than in fed fish from day 7 onwards. Moreover, plasma lysozyme concentrations were significantly higher in starved flounder from day 21 onwards. This result confirms that the response of olive flounder to short-term (less than about 1.5 months) starvation consists of a readjustment of metabolism rather than the activation of an alarm-stress response. The present results indicate that starvation does not significantly compromise the health status of fish despite food limitation.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.302-307
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• 1995

Four strains of lactic acid bacteria which produced bacteriocins inhibitory to Listeria species were isolated from Kimchi, and were identified as Leuconostoc mesenteroides subsp. mesenteroides (2 strains), Leuconostoc paramesenteroides and Pediococcus pentosaceus. The bacteriocins produced by the isolates inhibited all of the Listeria monocytogenes strains tested, but L. denigrificans 28 and L. welchimeri 89 were not inhibited by the bacteriocin produced by the Leu. paramesenteroides isolate. The bacteriocin produced by the P. pentosaceus isolate was more inhibitory against sensitive strains and showed broader spectrum of antimicrobial activity than those produced by other isolates. The bacteriocins produced by Leuconostoc isolates were sensitive to pronase E treatment, but that produced by the P. pentosaceus isolate was not completely inactivated. The bacteriocins produced by all of the isolates were not sensitive to catalase, ${\alpha}$-amylase and lysozyme and heat (30 min at $100^{\circ}C$) treatments.