• Fisheries and Aquatic Sciences
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• 제15권1호
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• pp.83-89
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• 2012

Flavobacterium johnsoniae was isolated from farmed rainbow trout Oncorhynchus mykiss in Korea, and its biochemical and molecular characterization was determined. Yellow-pigmented bacterial colonies were isolated from 18 of 64 fish samples (28.1%) on trypticase soy agar plates, and their biochemical profiles were characterized by API 20E and API 20NE test kits. F. johnsoniae was identified by biochemical phenotyping of factors including rapid gliding motility, Gram-negative condition, oxidase- and catalase-positive status, Congo red absorption, nitrate reduction, ${\beta}$-galactosidase production, acid production from glucose, and gelatin and casein hydrolysis. PCR and subsequent sequencing of 16S rRNA confirmed that the yellow-pigmented colonies were most similar to F. johnsoniae. The alignment analysis of 16S rRNA sequences also showed that all 18 rainbow trout isolates had highly similar homologies (97-99% identity). One isolate was selected and named FjRt09. This isolate showed 98% homology with previously reported F. johnsoniae isolates, and in phylogenetic analysis was more closely grouped with F. johnsoniae than with F. psychrophilum, F. columnare, or F. branchiophilum. This is the first report on the occurrence and biochemical characterization of F. johnsoniae isolated from rainbow trout in Korea.

• Journal of Acupuncture Research
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• 제17권3호
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• pp.151-167
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• 2000

Objective : The aim of this study is to determine the antimutagenic effect and genetic safety of Buthus martensi Karsch aqua-acupuncture solution(BMKAS) against various chemical carcinogens. Method : Ames(Salmonella typhimurium) test and Rec assay(Bacillus subtilis) were used as indicators for DNA damage and antimutagenesis. Furthermore, the levels of umu operon expression by measuring the ${\beta}$-galactosidase activity wete monitored with the SOS umu test using S. typhimurium 1535 containing plasmid pSK1002. And the host-mediated assay was used to investigate the mutagenicity and antimutagenicity of BMKAS inducing various chemical carcinogens after the activation with in vivo metabolic systems. Results : From the results, BMKAS did not atfect DNA of S. typhimurium and B. subtilis strains and showed no mutagenicity at the all concentrations of tested solution. Furthermore BMKAS dose-dependently protected the mutagenecity by AF-2, 2-AA and B[a]P. These phenomena was also similar to that after metabolic activation of BMKAS in in vivo system. Conclusion : These results suggested that BMKAS did not show the mutagenicity and protected the mutagenesis against various chemical carcinogens by four different methods used in this study.

• 약학회지
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• 제32권5호
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• pp.328-333
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• 1988

Based on the following tests with fractions extracted from organic solvents such as benzene, chloroform, ethyl acetate and methanol, this study is to analyse the antimutagenicity of Lonicerae Flos. When carrying out Ames test with Salmonella typhimurium strain, it seemed that there was stronger antimutagenicity in TA 100 treated by MNNG than did one in TA 98 by NPD, and that there was stronger antimutagenicity through base pair exchange than one through frame shift. In the umu test, each fraction tended to inhibit the activity of ${\beta}-galactosidase$ induced by AF-2. As shown in these above tests, the ethyl acetate fraction was the strongest among four fractions. On the other hand, its component consisted of luteolin, apigenin, chlorogenic acid and five unknown ingredients. Of these unknown ingredients, E, F strongly tended to inhibit the activity of ${\beta}-galacosidase$. In addition,there was also the decrease in its activity of apigenin, luteolin and chlorogenic acid.

• 한국식품영양과학회지
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• 제24권2호
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• pp.313-322
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• 1995

This study was conducted to investigate the effect of ginseng on the preservability and quality of Chinese cabbage Kimchi. The effect of ginseng on the growth of Lactobacilli, pH, titratable acidity, amount of juice, sensory quality and fracitonation of cell wall ploysaccharides, and enzyme activities related to softening were examined during fermentation. Ginseng promoted the growth of L. brevis and it didn't influence L. plantarum and L. fermentum. But Leuc. mesenteroides and P. cerevisiae was inhibited a little by adding of ginseng. The quality of ginseng added Kimchi evaluated by nalysis of the pH, acidity, sensory quality, the amount of juice, and overall eating quality during fermentation was better than those of control Kimchi, and 2% ginseng added Kimchi was the best ont the preservability and quality. The activity of β -galactosidase in ginseng added Kimchi was higher than that of control Kimchi. But the activity of polygalacturonase in ginseng added Kimchi was the same as that of control Kimchi. Ginseng added Kimchi showed more desirable softness of tissue. This was the same result as the analysis of pectic substance and hemicellulosic polysaccharides composed of cell wall polysaccharides. The value of L(lightness) of ginseng added Kimchi was highly maintained during the edible period and the yellow color from the ginseng was moved to Kimchi tissue in the ginseng added Kimchi.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.670-676
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• 2000

Several clones obtained from Serratia marcescens stimulated E. coli TP2139 (${\Delta}lac, \;{\Delta} crp$) cells to use maltose as a carbon source. The crp gene clone, pCKB12, was confirmed to stimulate the $\beta$-galactosidase activity, by Southern hybridization [31]. The nucleotide sequence of the crp region consisting of 1,979 bp was determined. The sequencing of the fragment led to the identification of two open reading frames: One of these, the crp gene, encoded 210 amino acid and the other encoded a truncated protein. The S. marcescens and E. coli crp genes showed a higher degree of divergence in their nucleotide sequence with 120 changes, however, the corresponding amino acid sequences showed only two amino acid differences. Yet, an analysis of the amino acid divergence revealed that the catabolite gene activator protein, the crp gene product, was the most conserved protein observed so far. Using a crp-lac protein fusion, it was demonstrated that S. marcescens CRP could repress its own expression, probably via a mechanism similar to that previously described for the E. coli crp gene.

• Journal of Microbiology and Biotechnology
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• 제16권10호
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• pp.1613-1621
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• 2006

Isolation and identification of algal lytic bacteria were carried out. Nine strains of algal lytic bacteria were isolated by the double-layer method using Anabaena flos-aquae as a sole nutrient. The isolate, AFK-13, showing the highest algal lytic activity was identified as Sinorhizobium kostiense based on the l6S rDNA sequence. The algal lytic experiments of the culture supernatants of AFK-13 demonstrated that the bacterial cell growth reached a maximum at 36-h culture, but the supernatant of 72-h culture exhibited the highest activity. Components among the extracellular products in the crude enzyme of the supernatant from S. kostiense AFK-13 culture were responsible for degradation of cell walls of Anabaena flos-aquae. Algal lytic assay tests of the culture supernatants suggest that the main substances for algal lytic activity could be proteinaceous. The activity of glucosidase was observed highly by polysaccharolytic analysis using the crude enzyme from S. kostiense AFK-13, whereas activities of galactosidase, mannosidase, rhamnosidase, and arabinosidase were also detected in low levels. The molecular weights (MW) of ${\alpha}-\;and\;{\beta}$-glucosidases were estimated to be approximately 50-100 kDa by the ultrafiltration method.

• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1553-1560
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• 2019

In a previous study, the antimicrobial peptides extracted from Lactobacillus plantarum UTNGt2 of wild-type fruits of Theobroma grandiflorum (Amazon) were characterized. This study aimed to investigate the antimicrobial mechanisms of peptides in vitro and its protective effect on fresh tomatoes. The addition of partially purified Gt2 peptides to the E. coli suspension cells at the exponential ($OD_{605}=0.7$) growth phase resulted in a decrease with 1.67 (log10) order of magnitude compared to the control without peptide. A marginal event (< 1 log10 difference) was recorded against Salmonella, while no effect was observed when combined with EDTA, suggesting that the presence of a chelating agent interfered with the antimicrobial activity. The Gt2 peptides disrupted the membrane of E. coli, causing the release of ${\beta}$-galactosidase and leakage of DNA/RNA molecules followed by cell death, revealing a bacteriolytic mode of action. The tomatoes fruits coated with Gt2 peptides showed growth inhibition of the artificially inoculated Salmonella cocktail, demonstrating their preservative potential.

• 한국미생물·생명공학회지
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• 제49권1호
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• pp.18-23
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• 2021

The aim of this study was to determine the production of folate, short chain fatty acids (SCFAs), and antimicrobial activity exhibited by Lactobacillus plantarum G72 for potential dietary application in pregnant women. L. plantarum G72 has been reported to possess characteristic activities and functionality including β-galactosidase activity and antioxidant activities. L. plantarum G72 showed antibacterial activity against pathogenic bacteria (Listeria monocytogenes ATCC 15313, Salmonella typhimurium P99, Escherichia coli ATCC 25922, and Staphylococcus aureus KCCM 11335) using a modified method, and formation of the largest inhibition zone was observed against S. aureus KCCM 11335 (12.0-17.0 mm). The adherence of four food-borne pathogenic bacteria to HT-29 cells was inhibited by L. plantarum G72 (0.13 to 0.92 log CFU/ml). The most considerable inhibition of adherence to HT-29 cells was observed by using L. plantarum G72 against S. typhimurim P99. Additionally, folate production by L. plantarum G72 was 50.1 ng/ml, and L. plantarum G72 produced relatively more lactic acid (11,176.73 mg/kg) than acetic, propionic, or butyric acids. Therefore, the results of this study suggest that L. plantarum G72 may serve as a multifunctional food additive in the health industry.

• Journal of Dairy Science and Biotechnology
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• 제38권4호
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• pp.207-221
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• 2020

This study aimed to investigate the physiological characteristics and anti-obesity effects of milk fermented by L. plantarum KI134. The lipase, α-amylase, and α-glucosidase inhibitory activities of milk fermented by L. plantarum KI134 was 94.57±1.25%, 9.44±2.85%, and 2.74±1.24% (10 fold dilution), respectively. L. plantarum KI134 showed higher sensitivity to clindamycin and erythromycin in comparison to sixteen different antibiotics. It demonstrated the highest resistance toward ampicillin and vancomycin. The strain showed higher β-galactosidase, leucine arylamidase, valine arylamidase, acid phosphatase, β-glucosidase, and N-acetyl-β-glucosaminidase activities compared to other enzymes. It also did not produce carcinogenic enzymes, such as β-glucuronidase. The survival rate of L. plantarum KI134 in 0.3% bile was 96.90%. Moreover, the strain showed a 91.45% survival rate at a pH of 2.0. L. plantarum KI134 has resistance to Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus at the rates of 70.00%, 68.18%, 59.05%, and 40.63%, respectively. L. plantarum KI134 (23.01%) showed higher adhesion ability than the positive control (16.32%) L. rhamnosus GG. These results demonstrated that milk fermented by L. plantarum KI134 demonstrated an anti-obesity effect under in vitro conditions, with confirmed potential as a probiotic.

• Journal of Dairy Science and Biotechnology
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• 제39권1호
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• pp.20-26
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• 2021

Lactase (β-galactosidase) is abundant in the small intestine during early childhood and gradually decreases with age. Lactic acid bacteria (LAB) present in yogurt could survive in the stomach, and lactase produced by these LAB can aid in lactose breakdown in the small intestine, thereby reducing lactose intolerance. This study aims to provide preliminary data for development of lactose-free yogurts for the elderly, and investigate the effect of lactose-hydrolyzed milk on the growth of starter cultures. The pH during yogurt fermentation using lactose-free milk was slightly higher at 2 and 4 h of incubation, but reached 4.5 at the end of incubation, similar to that of the yogurt prepared from regular milk. The number of viable cells of Streptococcus thermophilus reached 108 CFU/mL after 2 h of incubation and increased to 109 CFU/mL after 4 h of incubation. During yogurt fermentation, the viable cells of Lactobacillus species and Bifidobacterium longum did not affect lactose hydrolysis. Although lactose-hydrolyzed milk did not promote the growth of starter cultures, manufacturing yogurt with lactose-free milk could be beneficial for the intestinal health of lactose-sensitive elderly.