• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.801-806
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• 2002

A multiplex competitive polymerase chain reaction (PCR) method was developed for the rapid identification and quantification of Leuconostoc mesnteroides and Lactobacillus plantarum populations which are the key microorganisms in kimchi fermentation. The strain-specific primers were designed to selectively amplify the target genes encoding 165 rRNA of L. plantarum and dextransucrase of L. mesenteroides. There was a linear relationship between the band intensity of PCR products and the number of colony forming units of each model organism. The PCR quantification method was compared with a traditional plate-counting method f3r the enumeration of the two lactic acid bacteria in a mixed suspension culture and also applied to a real food system, namely, watery kimchi. The population dynamics of the two model organisms in the mixed culture were reliably predictable by the competitive PCR analysis.

• Environmental Engineering Research
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• v.17 no.1
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• pp.35-39
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• 2012

In this study, multiparametric flow cytometry (FCM) was installed to enumerate the diagnosis of Pseudomonas aeruginosa ATCC 10145 and Escherichia coli K12 (IFO 3301). The nucleic acids (DNA/RNA) were double stained by a LIVE/DEAD bacLight viability kit, involving green SYTO 9 and red propidium iodide (PI), based on the permeability of two chemicals according to the integrity of plasma membrane. As the results showed, the gate for dead bacteria was defined as the range of $0.2{\times}10^0$ to $6.0{\times}10^1$ photo multiplier tube (PMT) 2 fluorescence (X-axis) and $2.0{\times}10^0$ to $2.0{\times}10^2$ PMT 4 fluorescence (Y-axis), and the gate for live bacteria was defined as the range of $6.0{\times}10^0$ to $6.0{\times}10^2$ PMT 2 fluorescence (X-axis) and $2.0{\times}10^0$ to $4.0{\times}10^2$ PMT 4 fluorescence (Y-axis). In the comparison of the number of the tested bacteria detected by FCM (viability assessment) and plate culture (cultivability assessment), the number of bacteria detected by FCM well represented the number of bacteria that was detected by the colony forming unit (CFU) counting method when bacteria were exposed to isopropyl alcohol and silver/copper cations. Consequently, it is concluded that the application of FCM to monitor the functional effect of disinfectants on the physiological status of target bacteria can offer more rapid and reliable data than the plate culture colony counting method.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.457-462
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• 2022

This study is about the case applied of a shallow foundation reinforcement method for a low/mid-rise building where a relatively small load is applied by using a soil stabilized material that utilizes recycled resources. First, laboratory mixing test was conducted for four mixing ratios in order to derive the optimal mixing ratio in the field. Using the derived optimal mixing ratio, it was applied as a shallow foundation for the building in the field. The field application method used a simple process of compaction by the soil mixedure with the original soil and the soil stabilized material in the field. After field application, a plate bearing test was performed on one original ground and two improved ground to confirm the allowable bearing capacity. As a result of checking the bearing capacity, it was found that sufficient bearing capacity was exhibited.Therefore, it was confirmed that it can be used as a shallow foundation for the building.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.687-692
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• 1992

A simple method to determine viable cell numbers of each species in mixed culture was developed. The oxygen uptake rate (OUR) equals to the product of the specific OUR and the size of the microbial population. In a mixed culture, the OUR is a result of the respiration activities of each sub-population. The OUR was determined from the slope of the linear relationship between time and the decrease of dissolved oxygen concentration when aeration was stopped. The specific OUR was calculated from the slope of the viable cell number versus OUR curve. These values for C. lusitaniae at 20 and $30^{\circ}C$ were $1.36{\times}10^{-9}$ and $3.90{\times}10^{-9}$ and those for P tannoPhilus at 20 and $30^{\circ}C$ were $0.59{\times}10^{-9}$ and $1.86{\times}10^{-9}$ [(%/s)/(cells/ml)J. respectively. Using these values, viable cell numbers were calculated after the OURs of mixed culture at two temperatures were measured. A good agreement between the viable cell numbers determined by this method and by plate count was obtained.

• ALGAE
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• v.33 no.1
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• pp.21-35
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• 2018

The phototrophic dinoflagellate genus Scrippsiella is known to have a worldwide distribution. Here, we report for the first time, the occurrence of Scrippsiella lachrymosa in Korean waters. Unlike the other stains of S. lachrymosa whose cultures had been established from cysts in the sediments, the clonal culture of the Korean strain of S. lachrymosa was established from motile cells. When the sulcal plates of S. lachrymosa, which have not been fully described to date, were carefully examined using scanning electron microscopy, the Korean strain of S. lachrymosa clearly exhibited the anterior sulcal plate (s.a.), right sulcal plate (s.d.), left sulcal plate (s.s.), median sulcal plate (s.m.), and posterior sulcal plate (s.p.). When properly aligned, the large subunit (LSU) rDNA sequence of the Korean strain of S. lachrymosa was ca. 1% different from those of two Norwegian strains of S. lachrymosa, the only strains for which LSU sequences have been reported. The internal transcribed spacer (ITS) rDNA sequence of the Korean strain of S. lachrymosa was also ca. 1% different from those of the Scottish and Chinese strains and 3% different from those of the Canadian, German, Greek, and Portuguese strains. Thus, the Korean S. lachrymosa strain has unique LSU and ITS sequences. The abundances of S. lachrymosa in the waters of 28 stations, located in the East, West, and South Sea of Korea, were quantified in four seasons from January 2016 to October 2017, using quantitative real-time polymerase chain reaction method and newly designed specific primer-probe sets. Its abundances were >$0.1cells\;mL^{-1}$ at eight stations in January and March 2016 and March 2017, and its highest abundance in Korean waters was $26cells\;mL^{-1}$. Thus, S. lachrymosa has a nationwide distribution in Korean waters as motile cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.356-362
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• 1986

This experiment was designed to evaluate effects of freezing and frozen storage on survival of sanitary indicative bacteria in seafoods. Culture of bacteria such as Escherichia coli type I, Citrobacter freundii type I, Klebsiella aerogenes type I and Streptococcus faecalis was inoculated into homogenates of pollack, shrimp, and sardine frozen in a contact plate freezer at $-40^{\circ}C$ and chest freezer at $-20^{\circ}C$, stored at $-20^{\circ}C$, and then survival of the inoculated bacteria was determined over a period of 95 days. Coliform group was highly sensitive to freezing and frozen storage showing survival of about $2\%$ after 95 days of frozen storage at $-20^{\circ}C$, whereas Streptococcus faecalis was relatively resistant with $20\%$ survival rate. The sanitary indicative bacteria count was rapidly decreased in the early stage of frozen storage revealing 90 to $95\%$ loss of coliform group and 40 to $70\%$ loss in case of Streptococcus faecalis after 10 days storage. In determining recovery rate, most probable number (MPN) method gave more reproducible recovery of the tested strain than did the selected agar plate method.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.10-17
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• 2023

Dairy products are extensively used as carriers of probiotic strains that have potential health benefits. Assessment of the viability of probiotic strains during manufacturing is important to ensure that products meet recommended levels. Hence, the method for accurately quantifying lactic acid bacteria (LAB) in probiotic or dairy products is required. The present study aims to examine the performance of de-Man Rogosa Sharpe (MRS), plate count agar with bromocresol purple (PCA with BCP), and glucose blood liver (BL) agars recommended in the Korea Food Code guidelines for counting LAB. Analysis of the performance of culture media containing 19 lactic acid bacterial species commonly encountered in probiotic and dairy products showed no statistically significant difference between 18 reference strains and three culture media (p > 0.01). Furthermore, the suitability of three culture media was verified for the quantitative assessment of LAB in 25 probiotic and dairy products. The number of LAB in three culture media was determined to be more than 10⁷ colony-forming unit (CFU)/ml for fermented milk products and 10⁸ CFU/ml for condensed fermented milk and probiotic products, indicating that they all satisfied the Korea Food Code guidelines. Moreover, there was no statistically significant difference in the amount of LAB counted in all three culture media, suggesting that they can be used to isolate or enumerate LAB in commercial products. Finally, three culture media will be useful for isolating and enumerating LAB from fermented foods as well as gut microflora.

• Steel and Composite Structures
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• v.15 no.1
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• pp.57-79
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• 2013

This paper studies the dynamic instability of laminated composite plates under thermal and arbitrary in-plane periodic loads using first-order shear deformation plate theory. The governing partial differential equations of motion are established by a perturbation technique. Then, the Galerkin method is applied to reduce the partial differential equations to ordinary differential equations. Based on Bolotin's method, the system equations of Mathieu-type are formulated and used to determine dynamic instability regions of laminated plates in the thermal environment. The effects of temperature, layer number, modulus ratio and load parameters on the dynamic instability of laminated plates are investigated. The results reveal that static and dynamic load, layer number, modulus ratio and uniform temperature rise have a significant influence on the thermal dynamic behavior of laminated plates.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.189-199
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• 2000

To search for the antifungal substances, various actino-mycete isolates were obtained from various soils of Korea using plate dilution method on the humic acid vitamin agar plates. In the screening procedures using a dual culture method, 32 actionomycete isolates were selected, which showed the inhibitory activity against mycelial growth of plant pathogenic fungi Altirnaria mali, Colletotrichum gloeosporides, Fusarium oxysporum f.sp. cucumerinum, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. Bioassay of the crude extracts from culture filtrates and mycelial mets revealed that 12 antagonistic actionomycetes produced highly active antifungal substances. Actinomycete strain S5-55 which showed the substantial antifungal activity against the tested fungi was selected for production of the antifungal substances. Based on the cytochemical and morphological characteristics, strain S5-55 was identified as a Streptomyces species. The results of the numerical identification using the TAXON program confirmed that Streptomyces strain S5-55 was identical with Streptomyces humidus including in TAXON major cluster 19. The production of antifungal substance was most favorable when S. humidus strain S5-55 was cultivated for 10 dats on soluble starch broth supplemented with $K_2$HPO$_4$. The antifungal substances active against the plant pathogenic fungi P. capsici and M. grisea were partially purified using $\textrm{C}_{18}$ reversed-phase column chromatography.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.1
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• pp.19-27
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• 1993

For the purpose of this study was to determine the growth of Candide albicans on the surface of the resilient denture liners. The discs$(40\times40mm)$ of 2 resilient lining materals (Molloplast B, Mollosil) and one conventional acrylic resin (K-33) and one metal plate were processed and disinfected. Firstly, the test discs were placed into petri dish, and Candide albicans suspensions was overlayed on the test discs. And the test discs were incubated with intermitant shaking for 1 hour, 2 hours, 6 hours, 12 hours, 24 hours. After incubation, imprint culture method was achived and counted the colony on the agar plate. Secondly, the effect of denture cleansing agents on the growth of Candide alibicans on the resilient dentureliners was evaluated. The results were as follows : 1. The growth of Candida albicans on discs of Molloplast B and Mollosil was increased than that on discs of acrylic resin and metal plate (p<0.05). 2. As Candide albicans suspensions were incubated for 2 hours, the growth of Candida albicans on discs of Mollosil was increased than that on discs of Molloplast B (p<0.05), and the growth of Candide albicans on discs of metal plate was increased than that on discs of acrylic resin (p<0.05). 3. As Candide albicans suspensions were incubated for 6 hours, the growth of Candide albicans on discs of Mollosil was increased than that on discs of Molloplast B (p<0.05). 4. The growth of Candide albicans on discs of Mollosil and Molloplast B in treating denture cleansing agent was inhibited than control discs (p<0.05).