• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.414-419
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• 1996

The xylnX gene encoding a xylanase from Clostridium thermocellum ATCC27405 was cloned in the plasmid pJH27, an E. coli-Bacillus shuttle vector and the resultant recombinant plasmid, pJX18 was transformed into E. coli HB101. The overexpressed xylanase was found to be secreted into the periplasmic space of the recombinant E. coli cells. The crude enzyme was obtained by treating the E. coli cells with lysozyme, and purified by DEAE-Sepharose column chromatography. Molecular wieght of the xylanase was estimated to be 53 kDa by gel filtration. The pI value was determined to be pH 8.8. The N-terminal sequence of the enzyme protein was Asp-Asp-Asn-Asn-Ala-Asn-Leu-Val-Ser-Asn which was considered to be the sequence of that of the mature form protein. The Km value of the enzyme for oat spelt xylan was calculated to be 2.63 mg/ml and the Vmax value was $0.47 {\mu}mole/min$. The xylanase had a pH optimum for its activity at pH 5.4 and a temperature optimum at $60^{\circ}C$. The enzyme hydrolyzed xylan into xylooligosaccharides which were composed mainly of xylobiose (40%) and xyloltriose (12%) after 5 hour reaction. This result indicates that the xylanase from C. thermocellum ATCC27405 is an endo-acting enzyme.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.93-97
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• 2015

PURPOSE. Xerostomia can diminish the quality of life, leads to changes in normal chemical composition of saliva and oral microbiata, and increases the risk for opportunistic infections, such as Candida albicans. Various artificial salivas have been considered for patients with xerostomia. However, the knowledge on the antifungal and antiadhesive activity of artificial saliva substitutes is limited. The aim of the present study was to evaluate influence of two artificial salivas on the adhesion of Candida albicans to the polymethylmethacrylate disc specimens. MATERIALS AND METHODS. Two commercial artificial salivas (Saliva Orthana and Biotene Oral Balance Gel) were selected. 45 polymethylmethacrylate disc specimens were prepared and randomly allocated into 3 groups; Saliva Orthana, Biotene-Oral Balance gel and distilled water. Specimens were stored in the artificial saliva or in the sterile distilled water for 60 minutes at $37^{\circ}C$. Then they were exposed to yeast suspensions including Candida albicans. Yeast cells were counted using ${\times}40$ magnification under a light microscope and data were analysed. RESULTS. Analysis of data indicated statistically significant difference in adhesion of Candida albicans among all experimental groups (P=.000). Findings indicated that Saliva Orthana had higher adhesion scores than the Biotene Oral Balance gel and distilled water (P<.05). CONCLUSION. In comparison of Saliva Orthana, the use of Biotene Oral Balance Gel including lysozyme, lactoferrin and peroxidase may be an appropriate treatment method to prevent of adhesion of Candida albicans and related infections in patients with xerostomia.

• KSBB Journal
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• v.18 no.4
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• pp.289-293
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• 2003

Doxorubicin is an anthracycline-family polyketide compound with a very potent anti-cancer activity, typically produced by Streptomyces peucetius. In order to increase doxurubicin productivity, a semi-industrial doxorubicin-producing Streptomyces strain named BR-Dox was cultured in a R2YE liquid medium containing CaCO$_3$, and then converted to a cell wall-free protoplast using lysozyme treatment method, followed by PEG-mediated cell wall regeneration. Among several protoplast-regenerated Streptomyces BR-Dox strains, two independent isolates named BR-Dox4 and BR-Dox6 were visually selected using thin layer chromatography (TLC) based on the pigment overproducing phenotype. Comparing with Streptomyces BR-Dox parental strain, two protoplast-regenerated strains, BR-Dox4 and BR-Dox6 exhibited 25.2％ and 12.2％ higher doxorubicin productivity analyzed by high pressure liquid chromatography (HPLC), respectively. This result suggests that a protoplast-regeneration of an antibiotics-producing Streptomyces strain should be a promising strain development approach for antibiotics overproduction in Streptomyces species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.411-417
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• 2021

By-products produced from medicinal plants (MP) were evaluated as feed additives on growth performance, blood chemistry, and immune responses of the juvenile red lip mullet Liza haematocheila. A commercial diet was used as the control. Four experimental diets were prepared by combining 0.5% of MPs such as Panax ginseng (PG), Schisandra chinensis (SC), Angelica gigas (AG), and Rehmannia glutinosa (RG), via water absorption, to the control diet. Triplicate groups of fish averaging 61.8 g were fed one of experimental diets to apparent satiation for 8 weeks. Dietary supplementation of MPs did not affect the growth performance, biological indices and whole body composition of fish compared to the control. The fish fed with AG diet had an increased weight gain, and specific growth rate compared to fish in SC group. Decreased level of plasma glucose was observed in fish fed diet containing MPs. Lysozyme activity was significantly increased in the fish fed AG diet compared to that of fish in PG group. These results indicate that dietary supplementation of Angelica gigas may enhance growth performance and immune responses in juvenile red lip mullet.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.617-623
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• 2021

The study was conducted to investigate the dietary supplementation of citrus by-product (CBP) and CBP fermented with Bacillus subtilis (BS) or B. pumilus (BP) on growth performance, feed utilization, innate immune responses and disease resistance of Korean rockfish Sebastes schlegelii. Triplicate groups of juvenile fish (initial weight of 22.9 g) were fed one of five experimental diets which were formulated to replace a synthetic vitamin C (L-ascorbyl-2-polyphosphate, LAPP) with CBP or fermented CBP. A basal diet without LAPP and CBP was used as the control diet (Con). At the end of the 13 weeks feeding trial, growth performance, feed utilization and survival of fish fed the Con were significantly lower than those of fish fed the LAPP, CBP and fermented CBP diets. Fish fed the Con were significantly lower in lysozyme activity than fish fed LAPP, CBP and fermented CBP diets. In a challenge test against Edwardsiella tarda, cumulative mortality of fish fed LAPP, CBP and fermented CBP diets was significantly lower (20-30%) than that of the Con (60%). The findings in this study indicate that the CBP and/or fermented CBP can be a promising vitamin C source for LAPP replacement in diet for Korean rockfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.634-643
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• 2021

Han In-jin (Artemisia iwayomogi Kitamura) and Cham Dang-gwi (Angelica gigas Nakai) exhibit antibacterial, antiparasitic, antifungal, and antiviral properties in vitro. In this study, mixture of the extracts of these two medicinal plants was absorbed on pellets. Thereafter, these pellets were fed to olive flounder Paralichthys olivaceus for 12 weeks at laboratory (1^st experiment) and 24 weeks at field test (2^nd experiment), and the immune activity and disease resistance properties of the extracts were examined. It was observed that lysozyme activities of plasma, spleen, and kidney improved after 12 weeks. Furthermore, when the olive flounders were artificially infected with bacterial pathogens, their cumulative mortality decreased in the group that was fed the extracts for 12 weeks compared to that in control group, and the relative percent survival also improved. This study concluded that mixture of Han In-jin and Cham Dang-gwi extracts provides disease resistance in vivo.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.532-540
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• 2023

This study aimed to evaluate the effects of dietary supplementation with two different types of hydrolyzed blood meal (HBM) on the growth performance, feed utilization, digestibility and innate immunity of olive flounder Paralichthys olivaceus. A control diet (Con) consisting of 60% fish meal was formulated and four diets containing two different types of HBM at varying concentrations were prepared 2.5 and 5.0% liquid HBM (L2.5 and L5.0) and 0.5 and 1.0% powdered HBM (P0.5 and P1.0). A total of 450 olive flounder (average body weight: 50±0.07 g) were distributed in 15 tanks (240 L), with three replicate groups per diet. The fish were fed the diets to apparent satiation for 9 weeks and subsequently exposed to Edwardsiella tarda. The results showed that fish fed L2.5, L5.0 and P0.5 diets exhibited significantly higher lysozyme activity compared to those fed the Con and P1.0 diets. During the challenge test against E. tarda, the L5.0 and P0.5 fish groups exhibited higher disease resistance than that of the Con group. These findings indicate that dietary supplementation with HBM could positively effect the innate immunity and disease resistance of olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.3
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• pp.300-308
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• 2023

This study aimed to evaluate the utilization of low fish meal (LFM) diet and black soldier fly (BSF) Hermetia illucens meal supplementation in LFM diet as a fish meal (FM) replacer or functional additive for juvenile olive flounder Paralichthys olivaceus. Three LFM diets were prepared to contain 30, 25, and 20% FM, respectively (designated as F30, F25, and F20). Three BSF diets were prepared by adding 2.0, 2.5, and 3.0% BSF in the LFM diets, respectively (designated as F30B2.0, F25B2.5, and F20B3.0). A total of 540 fish (initial mean body weight: 22.3±0.01g) were randomly distributed into 18 tanks (240 L) in triplicate groups and fed the experimental diets twice daily for 12 weeks. Results showed that there were no significant differences in the growth performance, feed utilization and survival among all the groups. Lysozyme activity significantly increased in F30B2.0 and F25B2.5 groups compared to their respective LFM groups. Total immunoglobulin was significantly higher in F30 group than in F20 group. Anti-protease and myeloperoxidase activities were significantly higher in F30B2.0 group than in F20 group. Innate immunity gradually decreased with decreasing FM level in all the groups. BSF supplementation significantly improved immunity compared to their respective LFM diets. Therefore, BSF could be used as an immuno-stimulant supplement in LFM diets for P. olivaceus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.850-860
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• 2023

The effects of dietary mannan oligosaccharides, Lactobacillus plantarum, Bacillus subtilis, and Bacillus licheniformis supplementation on hybrid grouper Epinephelus akaara ♀×Epinephelus lanceolatus ♂ were evaluated. The fish were fed a basal diet and five other diets consisting of 0.6% mannan oligosaccharides, L. plantarum, B. subtilis, and B. licheniformis and mixture of each 0.15% prebiotic and all the probiotics (designated as MOS, LP, BS, BL, and SYN) for 56 days. Growth performance and feed utilization showed no significant differences among all experimental groups. Lipid level of whole-body was significantly high in MOS and BL groups. Plasma aspartate aminotransferase was significantly low in BL and SYN groups. Nitro-blue tetrazolium, lysozyme and anti-protease, and glutathione peroxidase in BS, SYN, and all probiotic groups, respectively, were significantly high. Intestinal Vibrio bacteria was significantly low in all probiotic and SYN groups. Gene expression of interleukin-1β and interleukin-10 in SYN group; transforming growth factor β2 in MOS and BS groups, toll-like receptor 2-2 in BS and BL groups; and C-type lectin in MOS, LP and SYN groups were significantly upregulated. Our findings indicate that mannan oligosaccharides, L. plantarum, B. subtilis, and B. licheniformis could improve innate immunity, antioxidant capacity, anti-inflammation, and intestinal microbiota of hybrid grouper.

• Applied Biological Chemistry
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• v.26 no.4
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• pp.222-230
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• 1983

This study was designed to develop a process for the immobilization of xylose isomerase(D-xylose ketol isomerase, EC 5.3.1.5) from Streptomyces griseolus previously isolated by the authors and its application on a pilot plant scale for the production of high fructose corn syrup. The biomass which has endo-excreted xylose isomerase was homogenized under a pressure of $500kg/cm^2$ and 90.8% of the enzyme recovery of the native activity was obtained as compared to 54.7% recovery by the lysozyme treatment. Ionic bonding method was adopted for the enzyme immobilization due to its many reported merits. It was found that the porous resins such as Diaion HP 20, Duolite A-7, Amberlite IRA 93 and 94 were effective in immobilizing the enzyme. In addition, it was disclosed that the regeneration form of $BO_4--$ is effective for Amberlite IRA 93 and $HCO_3-$ for Diaion HP 20. Optimal immobilization condition for Amberlite IRA 93 was pH 8.0 and $55^{\circ}C$ yielding 80.6% of immobilization. Activity decay test showed half life of the immobilized enzyme with Amberlite IRA 93 was more than 24 days at $65^{\circ}C$. The carrier was evaluated to be resuable and its result showed the relative immobilization yields were 98.2, 93.3, 90.7 and 87.5%, respectively at second, third, forth and fifth rebinding test of the enzyme on Amberlite IRA 93. Optimal temperature of the immobilized enzyme was slightly lowered and the range widened to $60\sim70^{\circ}C$, while optimal pH moved toward $8.0\sim8.3$ in its isomerization reaction. The trial production result of high fructose corn syrup in pilot scale immobilization showed that one liter of immobilized xylose isomerase (350 IXIU/ml-R) is capable producing about 293l high fructose corn syrup(75% dry substance) in 30 days.