• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.122-129
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• 1998

It were reported that antifungal mechanism of Enterobacter cloacae is a volatile ammonia that produced by the strain in soil, and the production of ammonia is related to the bacterial urease activity. A powerful bacterium SH14 against soil-borne pathogen Fusarium solani, which cause root rot of many important crops, was selected from a ginseng pathogen suppressive soil. The strain SH14 was identified as Bacillus subtilis by cultural, biochemical, morphological method, and $API^{circledR}$ test. From several in vitro tests, the antifungal substance that is produced from B. subtilis SH14 was revealed as heat-stable and low-molecular weight antibiotic substance. In order to construct the multifunctional biocontrol agent, the urease gene of Bacillus pasteurii which can produce pathogenes-suppressive ammonia transferred into antifungal bacterium. First, a partial BamH I digestion fragment of plasmid pBU11 containing the alkalophilic B. pasteurii l1859 urease gene was inserted into the BamH I site of pEB203 and expressed in Escherichia coli JM109. The recombinant plasmid was designated as pGU366. The plasmid pGU366 containing urease gene was introduced into the B. subtilis SH14 with PEG-induced protoplast transformation (PIP) method. The urease gene was very stably expressed in the transformant of B. subtilis SH14. Also, the optimal conditions for transformation were established and the highest transformation frequency was obtained by treatment of lysozyme for 90 min, and then addition of 1.5 ${mu}g$/ml DNA and 40% PEG4000. From the in vitro antifungal test against F. solani, antifungal activity of B. subtilis SH14(pGu366) containing urease gene was much higher than that of the host strain. Genetical development of B. subtilis SH14 by transfer of urease gene can be responsible for enhanced biocontrol efficacy with its antibiotic action.

• Journal of Aquaculture
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• v.22 no.1
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• pp.105-111
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• 2009

In this study, we carried out an experiment for estimation the larval digestibility in aspects which digestive enzymatic activities and nutrition of the rotifers, Brachionus rotundiformis. Thus we enhanced the digestive enzymatic activity through the addition of starch for the increase of digestibility of rotifer (starch-rotifer), and compared with the feed efficiency through rearing of the olive flounder, Paralichthys olivaceus used rotifer lipid-enriched with Algamac $2000^{(R)}$ (CE-rotifer). The digestive enzyme activities (except for TG-lipase), total protein contents, total essential amino acid, essential amino acids (methionin and phenylalanine) of starch-rotifer (the rotifer used a starch as additive, and enriched not) was assayed significantly higher than CE-rotifer (P<0.05). And total lipid, lipid classes (except for sterol) and fatty acids as DHA and EPA showed higher in CE-rotifer than starch-rotifer (P<0.05). But, sterol contents and ST/TG ratio were shown significantly higher in starch-rotifer (P<0.05). The flounder larvae supplied the two rotifers showed standard length and body weight that not significantly differed with ranges $3.72{\sim}3.79\;mm$ and $32.9{\sim}37.8\;mg$/larva on 6 days after hatching (DAH), respectively (P>0.05). However, these of 12 DAH showed the values of significantly higher to $5.94{\pm}0.249\;mm$, $144.0{\pm}23.86\;mg$/larva and $26.2{\pm}12.13%$ in standard length, body weight and survival in CE-flounder than that of starch-flounder (P<0.05). The hydrolytic enzymatic activities of flounder larvae severally supplied the two rotifers showed the significantly higher activities in acidic -amylase, neutral -amylase, TG-lipase, lysozyme and acidic phosphatase in starch-flounder on 5 DAH (P<0.05). But neutral $\alpha$-amylase, three proteases and two phosphatases of CE-flounder on 11 DAH showed the significantly higher activities than that of starch-flounder (P<0.05). Therefore, for the flounder, Paralichthys olivaceus larvae just depleted yolk was more beneficial to supply the feed, rotifer, enhanced the digestibility than to supply the feed lipid-enriched for aspect of larval digestibility up to 6 DAH, thereafter nutrition of absorption due to the development of digestive organs suggested that enrichment effect appeared with larval somatic growth. Consequently, investigation more detailed about the larval digestive physiological and nutritional requirement variations after 6 DAH will be necessary, thereafter.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1656-1664
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• 2015

The effects of lightyellow sophora, Sophora flavescens extract were tested on non-specific immune response and a disease resistance of olive flounder, Paralichthys olivaceus. For feeding trial, weight gain of fish fed different treated groups were not significant differences. Serum analysis of treated and control group did not demonstrated any differences. Lysozyme activity in the kidney and spleen of the 0.05% treated group on $4^{th}$ and $8^{th}$ week showed significant increase, respectively. In addition, phagocytic activity of the 0.05% treated group on $4^{th}$ and 8th week showed significant increase compared to the control group. Histopathology of the liver and kidney tissue of the administrated group for $4^{th}$, $8^{th}$ and $12^{th}$ week showed no particular signs of tissue degeneration. The treated group was higher than control group by analyzing the relative percent survival (RPS) of the experimental challenge of Edwardsiella tarda. Therefore, the lightyellow sophora showed effective in preventing fish-pathogenic edwardsiellosis for a certain period of time.

• Journal of Life Science
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• v.13 no.1
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• pp.90-98
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• 2003

An allium rhizobacterium Serratia plymuthica AL-1 was previously selected as a biocontrol agent of allium white rot. The chitinase from S. plymuthica AL-1 produced in medium containing colloidal chitin was purified by ammonium sulfate precipitation (40~70%), affinity adsorption, column chromatography on DEAE-sephadex A-50 and sephadex C-200 gel filtration. The enzyme was purified 10.8-fold with a yield of 7.3% from the starting culture broth. The purified chtinase gave a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis, it's molecular weight was estimated to be 55 kDa. The optimum pH and temperature of the purified enzyme were pH 5.5 and $55^{\circ}C$, respectively and it is stable up to $50^{\circ}C$ and maintains around 90% of its activity for 60min. The enzyme were activated by $Ca^{2+}$, $Mn^{2+}$ and $Mg^{2+}$ and inhibited by $Cu^{2+}$, SDS, $\rho$-CMB, MIA, respectively. The purified chitinase showed broad spectrum of antifungal activities against plant pathogenic fungi Sclerotium cepivoruin, Alternana alternnta, Colletotrichum glceosporioidrs, Phoma sp., Sclerotinia sclerotiorum, Stemphylium solani, Fusarium oxysporium f. sp. niveum but rarely inhibited Phytophthora capsici and Pythium ultimum.. The purified chitinase from S. plymuthica AL-1 caused swelling, lysis, deceleration and degradation of the hyphal tips of S. sczerotiorum causing allium white rot. It suggest that S. prymuthica AL-1 chitinase play an important part in the bifunctional chitinase / lysozyme activity.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1640-1650
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• 2016

In this study, the effect of the polychaete antimicrobial peptide as feed additives on fish, olive flounder (Paralichythys olivaceus) and black rockfish (Sebastes schlegelii), immune activity was described. The antimicrobial peptide of the polychaete was induced by peptidoglycan from Micrococcus luteus. The fish were fed an experimental diet supplemented with 0%, 0.05%, 0.1%, 0.5% or 1% of immune induced the polychaete to a commercial diet. Haematological parameters, nonspecific immunes and stress were evaluated 2, 4, 6 and 8 weeks during fed. The resistance against bacteria, Edwardsiella tarda and Streptococcus iniae, were analysed on after 8 weeks. The haematological parameters were not significantly changed among tested groups. But the lysozyme activities were significantly high in the 0.1% and 0.5% supplement group of olive flounder and black rockfish, respectively. Additionally, cortisol in plasma was low in the 0.1% and 0.5% supplement group of olive flounder and black rockfish, respectively. And resistance of these supplement groups were significantly induced against bacterial injection.

• Journal of fish pathology
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• v.23 no.3
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• pp.389-398
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• 2010

Effects of various concentration of yuzu Citrus junos Siebold ex Tanaka in the diets on growth, blood chemistry and disease resistance of olive flounder were determined. Fifteen hundred fish averaging 200~270g were fed on moist pellet containing yuzu at the concentrations of 0%(control), 2.5%, 5% and 7.5% for 3 months. After feeding trial, weight gain of fish fed 2.5% and 5.0% yuza diet was higher than those of fish fed 0% and 7.5% yuza diet but not significant(P>0.05). No differences in hematological and physiological indices of olive flounder were found among the experimental diets except for total cholesterol. Serum lysozyme activity was not significantly different among fish fed experimental diets but bactericidal activity of fish fed 7.5% yuza diet was significantly different from those of fish fed 0, 2.5 and 5% Yuza diets. Survival rates of fish fed 2.5% yuza diet at experimental infection with Edwardsiella tarda and Streptococcus sp. were higher than those of the other experimental groups but not significant. In conclusion, Dietary inclusion of 2.5~5% yuzu seems to have positive effects for fish health condition and disease resistance.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.347-353
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• 2022

In this study, the effect of a synbiotic mixture of probiotics and 3% inulin on the growth, non-specific immune response, and mortality due to disease resistance of Paralichthys olivaceus was investigated. The results revealed that an 8-week diet of synbiotic-added feed, had no significant effect on the growth of P. olivaceus, Analysis of the hematological parameters revealed that there was a significant difference in the content of AST, total protein, and cholesterol among the groups, whereas there was no significant difference in the ALT and glucose contents. Further, there was no significant difference in the lysozyme activity of the synbiotic and control group after 8 weeks' feeding. In addition, when the symbiotic mixture was used rather than probiotics alone, the NBT activity of the synbiotic group increased compared to that of the control group. Moreover, when only probiotics were used, the cytokine expression in the spleen of the samples was significantly lower than that in the control group, whereas the expression was significantly higher in the spleen of the synbiotics group. However, there was no significant difference in the cytokine expression in the liver, intestine, and kidney of the three groups. Lastly, after injection for 2 weeks, the mortality rates of the control group towards Edwardsiella tarda, Streptococcus parauberis, and Streptococcus iniae were 95, 85 and 85%, respectively; those of the probiotics group were 85, 80, and 80%, respectively; and those of the synbiotics group were 80, 80, and 85%, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.250-256
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• 2009

A 8-week feeding trial was conducted to investigate the effects of dietary supplementation of Kugija (Lycium chinense) on the growth and immunological response in juvenile Korean rockfish (Sebastes schlegeli). Six experimental diets were supplemented with Kugija at 0, 0.1, 0.5 1.0, 3.0 and 5.0% ($K_0,\;K_{0.1},\;Ko_{0.5},\;K_{1.0},\;K_{3.0},\;K_{5.0}$) on a dry-matter basis. After 2 weeks, triplicate groups of 30 fish initially averaging 3.36$\pm$0.2 g (mean$\pm$SD) were randomly distributed into the aquarium and were fed one of the experimental diets for 8 weeks. By the end of the 8-week feeding trial, fish fed the $K_{0.5}$ and $K_{1.0}$ diets exhibited a higher weight gain and specific growth rate than fish fed $K_0$ and $K_{0.1}$ diets (P<0.05). Feed efficiency of fish fed the $K_{0.5}$ diet showed significant higher value than that of fish fed the $K_0$, $K_{3.0}$ and $K_{5.0}$ diets (P<0.05). Hepatosomatic index of fish fed the $K_{0.5}$ diet was significantly higher than that of fish fed the $K_{0.1}$ and $K_{5.0}$ diets (P<0.05). Hematocrit of fish fed the $K_{0.5},\;K_{1.0}$ and $K_{5.0}$ diets was significantly higher than that of fish fed the $K_0$ diet (P<0.05). Glutamic oxaloacetic transaminase of fish fed the $K_{0.5},\;K_{1.0},\;K_{3.0}$ and $K_{5.0}$ diets was significantly lower than in fish fed the other diets (P<0.05). Glutamic pyruvic transaminase activity of fish fed the $K_{3.0}$ diet was significantly lower than those of fish fed the $K_0$ and $K_{0.1}$ diets (P<0.05). However, there was no significant difference in the activity of the transaminase in fish fed the $K_{0.5}\;K_{1.0},\;K_{3.0}$ and $K_{5.0}$ diets. Lysozyme activity of fish fed the $K_{0.5}$ and $K_{1.0}$ diets was significantly higher than that in fish fed the $K_0$ and $K_{0.1}$ diets (P<0.05). Respiratory burst activity of fish fed the $K_{3.0}$ diet was significantly higher than those of fish fed the $K_0$ and $K_{0.1}$ diets (P<0.05). However, there was no significant difference in respiratory burst activity of fish fed the $K_{0.5}\;K_{1.0},\;K_{3.0}$ and $K_{5.0}$ diets. Fish fed Kugija showed lower early mortality than fish fed a Kugija-free diet upon challenge with Vibrio ordalii. The results suggest that feeding of Kugija (Lycium chinense) enhances growth, non-specific immunity and disease resistance in juvenile Korean rockfish.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.428-434
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• 2009

This study was conducted to evaluate the anti-hypertensive effect of Lactobacillus sp. isolated from Kimchi by examining its effects on renal angiotensin-converting enzyme (ACE) inhibitory activity, lipid components and blood pressure using the spontaneously hypertensive rat (SHR) system. Most Lactobacillus sp. extracts (lysozyme, sonication and ethyl acetate extracts) showed higher capacities for the inhibition of ACE activity than those of cultured media. Particularly, LG 7, 8 and 42 of Lactobacillus sp. showed the strongest inhibitory activity among the Lactobacillus sp. extracts. The concentrations of total cholesterol and triglycerides in the serum were lower in the Lactobacillus sp. administration groups than in the control group, but these differences were not significant. The HDL-cholesterol concentrations of the LG 42 administration groups (IX, X) were significantly higher than that of the control group. At 4 weeks, the systolic blood pressure (SBP) in the LG 42 Lactobacillus sp. ($1{\times}10^9$ cfu/mL) group (XI) was about 27% lower than that of the control group (V). No adverse effects were observed on the liver and there was no difference in the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values among groups. The results of this study suggest that long term consumption of LG 42 Lactobacillus sp. may be beneficial to the prevention of high blood pressure.

• Fisheries and Aquatic Sciences
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• v.22 no.10
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• pp.23.1-23.10
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• 2019

Background: Taurine is a conditional essential amino acid for fish. A study was conducted to investigate the compensating effect of supplemental taurine in diets for red seabream (Pagrus major) on impaired growth performance by fish meal (FM) replacement with soybean meal (SM) at low water temperature (14.15 ± 1.95 ℃). Methods: A FM-based diet was considered as a high FM diet and three other experimental diets were formulated to replace FM with SM by 20, 35, or 50% (HFM, SM20, SM35, or SM50, respectively) without taurine and other four diets were formulated by adding 1% taurine to the diets (HFM-T, SM20-T, SM35-T, or SM50-T, respectively). Triplicate groups of fish (108.9 ± 1.58 g/fish) were distributed into 24 polyvinyl circular tanks (215 L) with 20 fish per tank and fed one of the diets to satiation for 20 weeks. Results: Growth performance and feed utilization of red seabream were significantly improved by the dietary taurine supplementation. SM20-T and SM35-T diets increased fish growth that are comparable to HFM diet. Feed intake, feed conversion ratio, and protein efficiency ratio of fish fed SM20-T and SM35-T diets were not significantly different from those of HFM group. Dietary taurine supplementation in each FM replaced group numerically increased innate immunity of the fish. Lysozyme and superoxide dismutase activities were significantly decreased in fish fed SM35, SM50, and SM50-T diets compared to those of fish fed HFM diet while they were not significantly lower in SM20, SM20-T, SM35, and SM35-T groups. Glutathione peroxidase activity was significantly lower in fish group fed SM50 diet while SM50-T group did not significantly lower compared to that of HFM group. The relative expression level of hepatic IGF-1 mRNA was improved in fish fed taurine-supplemented diets compared to their respective SM diets. Conclusions: Growth performance and feed utilization of red seabream can be accelerated or restored by 1% taurine supplementation when they are fed high level of SM up to 35% in diets during low water temperature season.