• Korean Journal of Agricultural Science
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• v.8 no.2
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• pp.238-243
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• 1981

This experiment was carried out to study the availability of Korean peat as a main carrier material of rhizobial inoculant, using the alfalfa strain Rhizobium meliloti M 14 which was isolated in the previous report. Modification of powdered peat with calcium carbonate and other materials was studied; inoculation of the peat with culture broth, maturation of the mixture under different conditions, and survival of the strain in the peat culture was examined. The results obtained were as follows. 1. Peat produced in Pyongtak was highly acidic, pH 3.8, and addition of calcium carbonate by 14% was required for pH adjustment to 6.4. However the amount of calcium carbonate could be reduced by 4 to 8% when carbon or charcoal was mixed with the peat. 2. Viable number of the strain reached to $7-9{\times}10^9cells/g$ after 3 days, when inoculated with the culture broth of early stationary growth phase and matured in unsteriled peat of open trays; and the number in steriled peat was $1.1-6.2{\times}10^{10}cells/g$ after 5 days, when matured in closed bottles. 3. Survival of the strain was affected markedly by storage temperature, and positive effect of D-sorbitol on the viability was recognized at elevated temperatures, when added as an additional carbon source and moistening agent. Glycerol, sorbitol, or sodium lactate was utilized by the strain as a sole source of carbon, and the decimal reduction time of viable number in the peat culture was was found to be 8 to 9 weeks at $25^{\circ}C$ when these agents were added by 0.5%.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.197-204
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• 1987

In order to know the growth of suspended cells by explant sources, the change of nitrogen contents of cultured cells following the growth periods, capability of micro-callus formation according to cell plating methods, growth of suspended cells on various media, and efficiency of micro-callus formation by using growth regulators and different N strengths were investigated. 1. When suspension culture was tried by using the callus induced from internode and petiole, cell fresh weight and packed cell volume increased with similar way and the growth reached at stationary phase after 12 culture days. 2. N-contents of cultured cells increased upto 3 days and decreased around 6days. But the values increased again upto 9 days, after that they showed gradual decreases. 3. Of cell plating methods, embedding method was the best for micro-callus formation. 4. Growth of suspened cells showed the rest performanoes, when they were cultured on LM medium with 1/2N strengths and BAP 0.01.2.4-D 0.1, and NAA $1.0mg/{\ell}$, after 15 cultured days(upto 76.9 folds). LM medium was better than MS or GD. The combination of auxin and cytokinin was better for cell growing than auxin-treatment only. 5. Micro-callus from single cell and small cell aggregates was formed only on MS and LM media with 2,4-D $1.0mg/{\ell}$.

• Microbiology and Biotechnology Letters
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• v.11 no.3
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• pp.223-231
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• 1983

The productions of beta-exotoxin from sixteen Bacillus thuringiensis strains were examined by Micrococus flava primarily, and then measured by spectrophotometer during culturing in Conner and Hansen mineral salts medium at 28$^{\circ}C$. Also the toxic effects of the toxin to mice were checked. The growth of Bacillus thuringiensis K2 and BTK2-T1, -T13, -T33 and -T40 got into stationary phase at 6 hour culture and then maintained it up to 48 hours without severe fluctuation. The production of beta-exotoxin from the strains, BTK2, BTK2-T1, -T13, -T17 and -T33 appeared at 6 hour culture and the amounts of the toxin were about 40 $\mu\textrm{g}$/$m\ell$ at 6 hour culture, approximately 70 $\mu\textrm{g}$/$m\ell$ at 12 hours, approximately 85$\mu\textrm{g}$/$m\ell$ from 24 hours to 48 hours. At 48 hour-culture, BTK2 produced 80 $\mu\textrm{g}$/$m\ell$ of beta-exotoxin (5.5$\times$10$^{8}$ cells/$m\ell$, BTK2-T13 produced 84 $\mu\textrm{g}$/$m\ell$ (4.3$\times$10$^{8}$ cells/$m\ell$), BTK2-T17 produced 87$\mu\textrm{g}$/$m\ell$ (1.4$\times$10$^{8}$ cells/$m\ell$), and BTK2-T33 produced 84 $\mu\textrm{g}$/$m\ell$ (4.9$\times$10$^{8}$ cells/$m\ell$). All other serotypes also produced beta-exotoxin. At 48 hour culture, BTK-37 produced 88$\mu\textrm{g}$/$m\ell$ (6.1$\times$10$^{8}$ cells/$m\ell$), BTK-35 produced 81 $\mu\textrm{g}$/$m\ell$), and the rest of them produced less than 70 $\mu\textrm{g}$/$m\ell$. To check the toxicity of beta-exotoxin and B. thuringiensis, the cultured media with microorganisms were inoculated to mice by per os, intraperiloneal, subcutaneous and intracerebral injection, and nasal cavity inoculation for 30 days. However, the toxin did not kill all of the treated mice.

• Food Science and Preservation
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• v.20 no.6
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• pp.863-870
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• 2013

This study was conducted to investigate the quality characteristics of kimchi with Allium hookeri powder (AHP) added during eight weeks fermentation at $4^{\circ}C$. AHP was added to salted cabbage at concentrations of 0, 0.1, 1, and 5% (w/w). The quality characteristics of the AHR-added kimchi were determined by measuring pH, acidity, salinity, reducing sugar, microbial amounts, and sensory properties. The vitamin $B_1$ and vitamin C contents of the Allium hookeri root were 0.04 mg/100 g and 5.76 mg/100 g, respectively. As for the mineral contents, the K content was highest, followed by the Ca, Mg, and Fe contents. The pH was higher in the kimchi with 0.1%, 1%, and 5% AHP than in the kimchi without AHP during the eight-week fermentation. The salinity ranged from 2.02% to 2.37% over the eight weeks. The microbial cells and lactobacilli increased rapidly throughout the fermentation in the exponential phase and hardly increased in the stationary phase. In the sensory evaluations, the overall acceptance, taste, and texture of the kimchi with 1% AHP added were highest. In conclusion, the kimchi with 0.1%, 1%, and 5% AHP generally showed better quality than the kimchi without AHP. Especially, the kimchi with 1% AHP had the best scores in quality and overall acceptance during the fermentation.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.69-75
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• 2017

Dormancy-associated protein (DRM) is involved in the dormancy physiology of plants and is conserved in almost all plant species. Recent studies found that DRM genes are involved in the abiotic stress response, and characterization studies of these genes have been conducted in several plants. However, few studies have focused on DRM genes in woody plants. Therefore, in this study, cDNA coding for DRM (PagDRM1) was isolated from poplar (Populus alba ${\times}$ P. glandulosa), and its structure and expression characteristics were investigated. PagDRM1 encodes a putative protein composed of 123 amino acids, and the protein contains two conserved domains (Domain I and Domain II). PagDRM1 is present as one or two copies in the poplar genome. Its expression level was highest in the stem, followed by mature leaves, roots, and flowers. During the growth of cultured cells in suspension, PagDRM1 was highly expressed from the late-exponential phase to the stationary phase. In addition, PagDRM1 expression increased in response to drought, salt stress, and treatment with plant hormones (e.g., abscisic acid and gibberellic acid). Therefore, we suggested that PagDRM1 not only plays an important role in the induction of dormancy, but also contributes to stress tolerance in plants.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2021-2026
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• 2009

Toluene, xylene and styrene are volatile organic solvents that are commonly used in mixtures in many industries. Because these solvents are metabolized and then excreted in urine, their urinary metabolites are thought to be biomarkers of occupational exposure to these solvents. Therefore, a simple, rapid, and yet reliable analytical method for determining the metabolites is required for accurate biological monitoring. In the present study, a simple and rapid HPLC-UV method was developed for the simultaneous determination of eight major metabolites of toluene, xylene and styrene: hippuric acid (HA), mandelic acid (MA), o-, m- and p-methylhippuric acids (o-, m- and p-MHAs), and o-, m- and p-cresols. A monolithic column was employed as the stationary phase and several conditions, including flow rate, composition of mobile phase and column temperature, were variables for the optimization of the chromatographic resolution. All eight metabolites were successfully resolved within 5 minutes in 10% aqueous ethanol containing 0.3% acetic acid and 1.6% $\beta$-cyclodextrin, using a flow rate gradient of 1.0 - 5.0 mL/min at 25 ${^{\circ}C}$. The performance of this method was validated by linearity, intra- and inter-day accuracy, and precision. The linearity was observed with correlation coefficients of 0.9998 for HA, 0.9999 for MA, 0.9989 for o-MHA, 0.9998 for m-MHA, 0.9991 for p-MHA, 0.9997 for o-cresol, 0.9998 for m-cresol, and 0.9986 for p-cresol. The intra- and inter-day precision of the method were less than 5.89% (CV) and the accuracy ranged from 92.95 to 106.62%. The validity was further confirmed by analysis of reference samples that were prepared by the inter-laboratory quality assurance program of the Korea Occupational Safety and Health Agency (KOSHA, Seoul, Korea). All measured concentrations of the analytes agreed with the certified values.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.125-132
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• 2009

In order to develop probiotics which may be a viable alternative of antibiotic use in pig industry, five bacterial strains (Lactobacillus sp. HN 52, 92, 98, 235 and AP 116) possessing antimicrobial properties were selected from 500 strains isolates of pig intestines. The bacteriocin produced by Lactobacillus sp. HN 235 displayed a relative broad spectrum of inhibitory activity against all Enterococcus strains, Pseudomonas aeruginosa, Listeria monocytogenes and Clostridium perfringens using the spot-on-lawn method. The production of antimicrobial substance started in the middle of the exponential growth phase, reached maximum levels (6,400 AU/mL) in the stationary phase, and then declined. Bacteriocin activity remained unchanged after 30 min of heat treatment at $95^{\circ}C$ and stable from pH 2.0 to 10 for 1 h, or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.151-158
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• 2007

Among 68 strains of lactic acid bacteria (LAB) isolated from Dongchimi, a strain K11 was selected due to its bactericidal activity against Escherichia coli O157 The strain K11 was identified as Lactobacillus plantarum, based on physiological and biochemical characteristics. In the late exponential phase, La. plantarum K11 showed maximum bacteriocin activity (12,800 BU/mL) and maintained until the early stationary phase. The bacteriocin activity was completely inactivated by all the proteolytic enzymes such as pepsin, protease, proteinase K, papain, chymotrypsin, and trypsin, but the activity was not affected by catalase, a-amylase, lysozyme, and lipase, suggesting proteinaceous nature of the bacteriocin. Additionally, this activity was not affected in the pH range from 3.0 to 9.0 and under storage conditions like 30 days at -20,4, or $25^{\circ}C$. Although the bacteriocin activity was absolutely lost after 15 min treatment at 121, it was relatively stable at $70^{\circ}C$ for 60 min or $100^{\circ}C$ for 30 min. The activity was disappeared by treatment with acetone, benzene, ethanol, or methanol, but it was not affected by treatment with chloroform or hexane. The antibacterial activity of the bacteriocin was good against some LAB including Lactobacillus spp., Enterococcus spp., and Streptococcus spp., but not against food-borne pathogens such as Bacillus spp., Listeria spp., and Staphylococcus spp. as well as yeasts and molds. Especially, some intestinal bacteria such as Enterobacter aerogenes and E. coli were significantly affected by the bacteriocin of La, plantarum K11. Furthermore, the addition of 640 BU/mL resulted in the complete clearance of E. coli O157 after 10 hr.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1737-1741
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• 2014

An HPLC method for determination of naringin was developed to standardize it as a marker compound in Goheung yuzu extract as a functional health food. Optimum results were obtained by C-18 column chromatography using solvent mixtures (A: 0.5% acetic acid, B: acetonitrile) as the stationary phase and mobile phase. The method was fully validated and sensitive with a limit of detection (LOD) of 0.0218 mg/L and limit of quantification (LOQ) of 0.0661 mg/L. The method showed high linearity (coefficient of correlation=0.9986) and high accuracy, as recovery rates of naringin at concentrations of 1, 0.5, 0.1, 0.05 mg/mL were in the ranges of 95.74~98.25%, 97.67~101.01%, 97.33~104.64%, and 95.53~106.82%, respectively. Intra-day and inter-day variation, which are measures of method precision, were 1.39~1.95% and 0.17~1.49%, respectively. Therefore, the method could be used without modification for determination of naringin as a marker compound in Goheung yuzu extracts.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.81-86
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• 2011

Xylanase is a class of enzymes that hydrolyze the linear polysaccharide ${\beta}$-1,4-xylan into xylose. This enzyme is applied in the process of paper making and may be used for the process of biofuel production in the future. The Paenibacillus donghaensis JH8, isolated from Donghae deepsea sediment and reported as a novel bacterium, was known to degrade xylan and its xylanase was characterized in this study. The enzyme was maximally induced in the presence of 0.1% xylan. The production of xylanase was started at early logarithmic phase and reached about 55 miliunit at stationary phase of growth. The optimal temperature and pH of extracellular xylanase were found to be $40^{\circ}C$ and pH 6.0, respectively. The activity of xylanase was inhibited by the presence of $Ca^{2+}$, $Mn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, $Al^{3+}$ or EDTA, and activated by $K^+$, $Ag^+$ or DTT. This xylanase was stable at $40^{\circ}C$ for 120 min, but lost almost their activity in 30 min at $60^{\circ}C$. Zymography analysis of concentrated culture supernatant revealed one major band at 42 kDa and two faint bands at 68 and 120 kDa.