• Food Science of Animal Resources
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• v.28 no.5
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• pp.587-595
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• 2008

In order to develop a new starter for fermented milk, 1037 bacterial strains were isolated from raw milk. The strain that showed excellent acid producing and angiotensin converting enzyme (ACE) inhibitory activity (88.6%) was selected and identified as a Lactobacillus zeae based on the result of API carbohydrate fermentation pattern and 16S rDNA sequence. Lactobacillus zeae RMK354 was investigated further to study its physiological characteristics. It showed strong ACE inhibitory activity compared with commercial LAB starters tested. The optimum growth temperature of L. zeae RMK354 was $40^{\circ}C$ and it took 10 hr to reach pH 4.3 under this condition. L. zeae RMK354 showed more sensitive to penicillin-G, bacitracin, novobiocin, in a comparison of 14 different antibiotics, and showed most resistance to polymyxin B and vancomycin. It showed higher esterase and leucine arylamidase activities compared with 16 other enzymes. It was comparatively tolerant to bile juice and able to survive at pH 2 for 3 hr. It showed inhibitory activity against Salmonella Typhimurium with the rate of 60%. Based on these and previous results, L. zeae RMK354 could be an excellent starter culture for fermented milk with high level of ACE inhibitory activity.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.272-278
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• 2007

Proteases are enzymes that break peptide bonds between amino acids of other proteins and occupy a crucial position with respect to their applications in both physiological and commercial fields. In order to screen new source of protease, bacteria producing extracellular proteases at low temperature were isolated from deep sea water of East Sea, Korea. A bacterium showing the best growth rate and production of an extracellular protease at low temperature was designated HJ 47. The DNA sequence analysis of the 16S rRNA gene, phenotypic tests and morphology led to the placement of this organism in the genus Pseudoalteromonas. Although maximal growth was observed at $37^{\circ}C$, enzyme production per culture time was maximum at $20^{\circ}C$. At this temperature, extracellluar protease production was detected from the end of the exponential phage to stationary phase, and maximal at 15 hours after initial production. The optimum temperature and pH of the protease were found to be $35^{\circ}C$ and 8.

• Journal of Life Science
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• v.23 no.1
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• pp.110-115
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• 2013

A microorganism (strain AR1) producing an extracellular lipolytic enzyme was isolated from hot springs located in Beppu, Japan. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that AR1 belongs to the genus Geobacillus. This study focused on novel strategies to increase extracellular lipolytic enzyme production by this novel Geobacillus sp. AR1. Cultures of the AR1 strain grew within a wide temperature range (from 35 to $75^{\circ}C$); the optimum temperature was $65^{\circ}C$. The pH for optimal growth was 6.5, whereas the optimum pH for lipolytic enzyme production was 8.5. The presence of oils in the culture medium led to improvements in lipolytic enzyme activity. Soybean oil was the most efficient inducer, and it yielded better results when added in the exponential phase. On the other hand, the addition of chemical surfactants led to lipolytic enzyme production. Their addition to the culture could affect the location of the enzyme activity. The addition of Tween 20 in the stationary phase significantly increased the proportion of the extracellular enzyme activity. According to the results, following the addition of soybean oil and Tween 20 in the exponential and stationary phases, the extracellular lipolytic activity was increased 2.4-fold compared with that of a control.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.283-289
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• 2002

This study was performed to search for potential microorganism that has rapid fermenting and physiological function from anchovy sauce. We isolated three bacterial strains, JM-1, JM-2, and JM-3 with proteolytic and fibrinolytic activity from anchovy sauce. Among the 3 bacterial strains, JM-3 showed the strongest proteolytic and fibrinolytic activity. Bacterial strain JM-3 was gram-positive rod, motile and formed endospore. The 16S rRNA of bacterial strain JM-3 was amplified by PCR and then its sequence was determined by ABI 310 genetic analyzer. The 16S rRNA sequence of bacterial strain JM-3 was compared to BLAST DNA database and identified to Bacillus subtilis with 99% of homology. The optimum temperature, pH and NaCl concentration for growth of B. subtilis JM-3 were $40^{\circ}C$, 5.0 and 0%, respectively. The optimum temperature, pH and NaCl concentration for proteolytic and fibrinolytic enzyme production of B. subtilis JM-3 were same as optimum conditions for growth. At 20% of NaCl concentration which is common NaCl concentration of fish sauce, B. subtilis JM-3 showed about 60% of proteolytic and fibrinolytic activity of 0% NaCl concentration. From above results, we found that B. subtilis JM-3 will be able to used for starter of functional fish sauce.

• Food Science and Preservation
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• v.20 no.5
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• pp.727-734
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• 2013

The antifungal activity against cheese fungi by lactic acid bacteria isolated from kimchi was investigated. Eight fungi were isolated from cheese in the cheese ripening room. Two of them were identified as Penicillium and Cladosporium via ITS-5.8S rDNA analysis. Twenty-two species of lactic acid bacteria with antifungal activity were isolated from kimchi. Two of them were identified as Lactobacillus and Pediococcus via 16S rRNA sequence analysis. Of the 22 lactic acid bacteria species, six were selected (L. sakei subsp. ALJ011, L. sakei subsp. ALI033, L. sakei subsp. ALGy039, P. pentosaceus ALJ015, P. pentosaceus ALJ024 and P. pentosaceus ALJ026) due to their higher activity against the eight fungi isolated from cheese in the cheese ripening room; and among the six species, the P. pentosaceus ALJ015 and P. pentosaceus ALJ024 isolates from the Jeonju area kimchi and the L. sakei subsp. ALI033 isolate from the Iimsil area kimchi had higher antifungal activity than the other lactic acid bacteria. The minimum inhibitory concentration (MIC) of L. sakei subsp. ALI033 against the eight fungi isolated from cheese in the cheese ripening room was $62.5{\mu}g/mL$.

• Food Science and Preservation
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• v.22 no.6
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• pp.908-914
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• 2015

The objectives of this study were to isolate and characterize low temperature adaptation yeast and to obtain suitable yeasts strains for manufacturing Yakju. In this study, we isolated 482 wild yeasts from fermented foods. Out of these, 5 yeast strains were selected based on increased growth at low temperature ($15^{\circ}C$) and high ${\beta}$-glucosidase activity. To screen the aromatic level of isolates, media containing cerulenin and 5,5,5-trifluor-DL-leucine (TFL) were used. Y297 strain demonstrated tolerance against TFL and produced more than 13% alcohol. Y297 strain was identified a Saccharomyces cerevisiae based on the 26S rDNA gene sequences. Maximum cell growth was observed after 19 hr and 38 hr of incubation at $25^{\circ}C$ and $15^{\circ}C$, respectively. The exponential phase was followed by a lengthy stationary phase, at $15^{\circ}C$, when the cells remained high viable. Y297 strain demonstrated tolerance against alcohol (10%), glucose (60%) and salt(NaCl, 8%). ${\beta}$-glucosidase and esterase activity in Y297 were higher than those of controls at $15^{\circ}C$. Overall, these results indicated that using wild yeast strain, isolated from fermented food, affects the chemical characteristics of the brewed Yakju.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2889-2894
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• 2013

A new complex [$Ni(phen)(C_9H_8Br_2NO_3)_2{\cdot}2CH_3OH{\cdot}2H_2O$] [phen: 1,10-phenanthroline $C_9H_8Br_2NO_3$: 3,5-dibromo-L-tyrosine] was synthesized and characterized by IR, elemental analysis and single crystal X-ray diffraction. X-ray crystallography shows that Ni(II) ion is six-coordinated. The Ni(II) ion coordinates with four nitrogen atoms and two oxygen atoms from three ligands, forming a mononuclear Ni(II) complex. The crystal crystallizes in the Orthorhombic system, space group $P2_12_12$ with a = 12.9546 ${\AA}$, b = 14.9822 ${\AA}$, c = 9.9705 ${\AA}$, V = 1935.2 ${\AA}$, Z = 1, F(000) = 1008, S = 0.969, ${\rho}_{calcd}=1.742g{\cdot}cm^{-3}$, ${\mu}=4.688mm^{-1}$, $R_1$ = 0.0529 and $wR_2$ = 0.0738 for 3424 observed reflections (I > $2{\sigma}(I)$). Theoretical study of the title complex was carried out by density functional theory (DFT) method and the B3LYP method employing the $6-3l+G^*$ basis set. The energy gap between HOMO and LUMO indicates that this complex is prone to interact with DNA. CCDC: 908041.

• Korean Journal of Veterinary Service
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• v.37 no.2
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• pp.85-96
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• 2014

Total 99 strains of Campylobacter spp. were isolated from 117 cases of duck's fecal samples. Among 99 strains of Campylobacter spp. isolates, 93 strains (93.9%) were C. jejuni and 6 strains (6.1%) were C. coli. Prevalence of virulence and GBS associated genes of 72 C. jejuni isolates was determined by m-PCR. Among the 10 kinds of virulence associated genes, cadF, dnaJ, flaA and ceuE genes were detected in all of C. jejuni isolates from ducks, racR, pldA, iamA, ciaB, virB11 and docC genes were 87.5%, 84.7%, 77.8%, 48.6%, 13.9% and 11.1%, respectively. Antimicrobial susceptibility test was performed on 72 C. jejuni isolates. The rate of resistance were 62.5% for oxytetracycline, 55.6% for kanamycin, 54.2% for enrofloxacin, 50% for ciprofloxacin, 37.5% for tetracycline and nalidixic acid, 18.1% for ampicillin, 15.3% for streptomycin, and 6.9% for ofloxacin. All isolates were susceptible to erythromycin. The adherence (intracellular and extracellular bacteria) abilities of the 20 isolates to INT-407 cells were between $4.21{\pm}1.27{\times}10^4$ CFU/well and $1.053{\pm}0.451{\times}10^6$ CFU/well from the isolates of cj-55 and cj-52, respectively, and that can be expressed as 0.1033% to 5.2655% to the infecting inoculum. The invasion (intracellular bacteria) abilities of the 20 isolates to INT-407 were between $1.00{\pm}1.73{\times}10^3$ CFU/well and $8.47{\pm}5.16{\times}10^4$ CFU/well from the isolates of cj-13 and cj-47, respectively, and that can be expressed as 0.0050% to 0.4235% to the infecting inoculums. The average CFU/well of 20 campylobacters isolated from ducks for adherence to and invasion were $2.646{\pm}2.886{\times}10^5$ and $3.03{\pm}2.7{\times}10^4$ respectively, and that was $1.3230{\pm}1.2139%$ and $0.1516{\pm}0.1343%$ of the starting viable inoculum. There was considerable correlation ($R^2$=0.627) between the adherence and invasion ability of C. jejuni isolates for INT-407 cell.

• Journal of Life Science
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• v.23 no.3
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• pp.347-354
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• 2013

Innate immunity is the ability to differentiate infectious agents from self. The innate immune system is comprised of a complicated network of recognition and effector molecules that act together to protect the host in the early stage of an infectious challenge. Mannose-binding lectin (MBL or mannose-binding protein, MBP) belongs to the family of $Ca^{2+}$-dependent lectins (C-type lectin with a collagen-like domain), which are considered an important component of innate immunity. While it is associated with increased risk and severity of infections and autoimmunity, the most frequent immuno-deficiency syndrome was reported to be low MBL level in blood. Deficiency of human MBL is caused by mutations in the coding region of the MBL gene. Rat homologue gene of human MBL gene was used to study functions of wild type and mutant MBL proteins. Although extensive studies have yielded the structural information of MBL, the functions of MBL, especially mutant MBL, still require investigation. We previously reported the cloning of rat wild-type MBL gene and the production of a truncated form of MBL protein and its antibody. Here, we present the cloning of mutant MBL cDNA in collagen-like domain (R40C, G42D, and G45E) using site-directed mutagenesis and differential behaviors of wild type and mutant MBL in cells. The major difference between wild type and mutant MBL was that while wild type MBL was secreted, mutant MBL was inhibited for secretion, retained in endoplasmic reticulum, and still functioned as a lectin.

• Journal of Life Science
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• v.26 no.10
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• pp.1113-1120
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• 2016

Two bacterial strains producing extracellular man nanase were isolated from doenjang, a traditionally fermented soybean paste in Korea. The isolates, WL-6 and WL-11, were identified as Bacillus subtiis on the basis of their 16S rRNA gene sequences, morphological, and biochemical properties. Two genes encoding the mannanase of both B. subtilis WL-6 and B. subtilis WL-11 were each cloned into Escherichia coli, and their nucleotide sequences were determined. Both mannanase genes consisted of 1,086 nucleotides, encoding polypeptides of 362 amino acid residues. The deduced amino acid sequences of the two WL-6 and WL-11 mannanases, designated Man6 and Man11, respectively, differed from each other by eight amino acid residues, and they were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. The 26 amino acid stretch in the N-terminus of Man6 and Man11 was a predicted signal peptide. Both Man6 and Man11 were localized at the level of 94–95% in an intracellular fraction of recombinant E. coli cells. The enzymes hydrolyzed both locust bean gum and mannooligosaccharides, including mannotriose, mannotetraose, mannopentaose, and mannohexaose, forming mannobiose and mannotriose as predominant products. The optimal reaction conditions were 55°C and pH 6.0 for Man6, and 60°C and pH 5.5 for Man11. Man11 was more stable than Man6 at high temperatures.