• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.773-778
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• 2006

The objective of this study was to evaluate three verocytotoxin-producing Escherichia coli (VTEC) detection kits to detect the presence of VT genes: Doupath Verocytotoxin (GLISA) developed by MERCK, ProsPect Shiga Toxin E. coil (STEC) Microplate Assay (ELISA) developed by Remel, and a polymerase chain reaction method. Our laboratory verified artificially inoculated samples. All three methods could detect very low numbers of VTEC, but VT-PCR had the best sensitivity for VTEC detection. From April through September 2005, 257 ground-beefs from supermakets and traditional markets were examined for the presence of VTEC by polymerase chain reaction immediately after purchase and total viable counts (TVC) were determined. VTEC was isolated from 30 of 257 ground-beefs. A variety of serogroups was found, including 10 stains belonging to the virulence type EHEC, but major serogroups such as O157, O26 and O111 were nor found.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1320-1324
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• 2006

The pancreatic and neutrophil elastases are associated with several illnesses including lung and vascular diseases, various cancers, and pancreatitis. The development of a potent and specific inhibitor to the elastases could lead to new therapies. In this study, an agar diffusion method was modified to include a substrate-dye conjugate (Elastin-Congo red) as a substrate of elastase and an indicator of elastase inhibitory activity. The Elastin-Congo red agar plates consisted of 0.1 % Elastin-Congo red and 2.5% agar. The elastase and elastase inhibitors were simultaneously loaded into wells, ultimately resulting in halo formations in which the halo diameter decreased as the concentration of elastase inhibitor increased. The concentration of elastase inhibitor in the samples, therefore, was inversely proportional to the halo diameters. This simplified method provided an excellent correlation with the standard microplate technique, which uses a chromogenic substrate. The concentration of elastase inhibitor obtained from the culture supernatant of a recombinant elastase inhibitor produced by the yeast Pichia pastoris was easily determined. This study has established a simple modified and inexpensive agar diffusion method that is potentially useful for the identification, quantification, and screening of new elastase inhibitors.

• Korean Journal of Veterinary Service
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• v.21 no.3
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• pp.313-323
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• 1998

In order to establish a sensitive and specific diagnostic method for detection of antibody to Salmonella pullorum, a enzyme-linked immunosorbent assay(ELISA) was designed and standardized. The diagnostic efficacy of the established ELISA was compared with that of the serum plate agglutination test and immunodiffusion test for pullorum disease. 1. The chicken hyperimmune sera to Salmonella pullorum, S gallinarum, S typhimurium and S typhi were shown the cross reaction to S pullorum antigen by serum plate agglutination test. 2. When compared the cross reaction titer of microplate agglutination test for chickens hyperimmune sera, it was found that the titer were 64 in S pullorum, 32 in S gallinarum, 4 in S typhimurium and 8 in S typhi, respectively. 3. When compared the specificity of various antigen(HA, EA, PA and SA) by the immunodiffusion test, the most suitable antigen was phenol-treated bactrium. 4. The optimal concentration of S pullorum antigen for ELISA was 1 : 160 dilution of bacterium. 5. The efficacy of the ELISA for detection of S pullorum antibody was compared with serum Plate agglutination test and immunodiffusion test in chickens infected with S pullorum. The antibody was first detected at 6 days after infection using three tests examined. The antibody was alldetected at 9 days by ELISA, at 12 days by serumplate agglutination test, at 15 days by immunodiffusion test.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.68-74
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• 1997

One hundred and eighty two lactic acid bacteria, isolated mainly from kimchi, including reference strains were examined for their ability to utilize 95 carbon sources. The test strains were assigned to 5 major, 1 minor and 12 single-membered clusters based on the $S_{SM}$, UPGMA algorithm (at similarity of $80{\%}$). These aggregate clusters were equivalent to the genus Leuconostoc (aggregate cluster M and N), the genus Lactobacillus (aggregate cluster Q and R), and the genera Lactobacillus and Leuconostoc (aggregate cluster O and P) according to the database of the Biolog system. This study demonstrates that rapid identification and classification of isolates originating from kimchi can be achieved on the basis of such carbon source utilization tests.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.225-231
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• 1997

Elastase inhibitor (EI) producing microorganisms were screened by microplate-assay of culture broth using Succinyl-$(Alanine)_3$-Nitroanilide as a chromogenic substrate. The portion of microorganisms showed EI activity above 90% was about 2% of all assayed. Isolated SMF-11 showed relatively high EI activity after filtration using membrane filter of NMWL 3,000. SMF-11 was identified as Streptomyces sp. according to results of morphological or physicochemical identification. SMF-11 has both rectiflexible and spiral spore chains with smooth spore surface and cell wall contained LL-DAP, iso- and anteiso-fatty acids. The amino acids in cell wall were alanine, glutamic acid and glycine. Fifty unit characters for major cluster were tested and the data were analyzed numerically using the TAXON program. The isolate SMF-11 was identified as a strain of Streptomyces lavendulae.

• Journal of the Korean Chemical Society
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• v.66 no.3
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• pp.194-201
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• 2022

A simple, efficient, and cost-effective method has been employed for the synthesis of 2,4,5-trisubstituted imidazole derivatives (3a-j) containing quinoline substituent at 2^nd position. Title compounds were obtained by multicomponent reaction (MCR), involving aryl substituted 1,2-diketone, quinoline carbaldehyde and ammonium acetate in the presence of acetic acid solvent under mild reaction conditions. The newly synthesized quinoline containing imidazole derivatives were confirmed through FT-IR, ¹H-NMR, ¹³C-NMR and mass spectral analysis. In-vitro microplate alamar blue assay (MABA) to determine the MIC (minimum inhibitory concentration) values against Mycobacterium tuberculosis H37Rv was performed for the synthesized compounds. The synthesized compounds exhibited activity against Mycobacterium tuberculosis and among which compounds, 3d, 3f and 3i showed good activity. The highest activity was showed with compound 3i. The anti-mycobacterial activity results are well correlated with the computational molecular docking analysis, which was performed for the synthesized compounds prior to the evaluation of the activity.

• The Korea Journal of Herbology
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• v.24 no.4
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• pp.121-126
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• 2009

Objectives : To evaluate the radical scavenging and acetylcholinesterase (AChE) inhibitory activities of the ethylacetate (EtOAc)-soluble portion of a methanolic extract of Aster yomena, three different assay systems were performed. Methods : The antioxidant activity of A. yomena extract was tested as its capacity to scavenging free radicals of DPPH and $ABTS^+$, which has been widely used to evaluate the antioxidant activity of natural products from plant sources. AChE inhibitory activity was tested against mouse brain AChE by spectrophotometric method of Ellman using ELISA microplate reader. Results : The methanolic extract of A. yomena was fractionated and the EtOAc-soluble portion showed significant AChE inhibitory and free radical scavenging effects. Also the EtOAc-soluble portion revealed the highest phenolic contents as compared to the other extracts. Conclusions : These results indicate that phenolic compounds may be important constituents that give rise to the anti-AChE and antioxidative activities of A. yomena extract. Further phytochemical studies on this plant, for nutraceutical or pharmaceutical application, are warranted.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1216-1225
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• 2014

Biofilm-related infections of Candida albicans are a frequent cause of morbidity and mortality in hospitalized patients, especially those with immunocompromised status. Options of the antifungal drugs available for successful treatment of drug-resistant biofilms are very few, and as such, new strategies need to be explored against them. The aim of this study was to evaluate the efficacy of phenylpropanoids of plant origin against planktonic cells, important virulence factors, and biofilm forms of C. albicans. Standard susceptibility testing protocol was used to evaluate the activities of 13 phenylpropanoids against planktonic growth. Their effects on adhesion and yeast-to-hyphae morphogenesis were studied in microplate-based methodologies. An in vitro biofilm model analyzed the phenylpropanoid-mediated prevention of biofilm development and mature biofilms using XTT-metabolic assay, crystal violet assay, and light microscopy. Six molecules exhibited fungistatic activity at ${\leq}0.5mg/ml$, of which four were fungicidal at low concentrations. Seven phenylpropanoids inhibited yeast-to-hyphae transition at low concentrations (0.031-0.5 mg/ml), whereas adhesion to the solid substrate was prevented in the range of 0.5-2 mg/ml. Treatment with ${\leq}0.5mg/ml$ concentrations of at least six small molecules resulted in significant (p < 0.05) inhibition of biofilm formation by C. albicans. Mature biofilms that are highly resistant to antifungal drugs were susceptible to low concentrations of 4 of the 13 molecules. This study revealed phenylpropanoids of plant origin as promising candidates to devise preventive strategies against drug-resistant biofilms of C. albicans.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.567-575
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• 1989

This study was conducted to evaluate the possibility of application of a microenzyme-linked immunosorbent assay(micro-ELISA) for the serodiagnosis of specific toxoplasma antibodies in swine sera and this test was performed as a microplate system by coating the polystyrene plates with toxoplasma soluble antigen, incubated serially diluted sera, then added horse radish peroxidase labelled goat anti-swine IgG(r) conjugate followed by o-phenylenediamine as substrate. The color development by enzyme-substrate reaction was determined by the photometric reading [ELISA reader at 490nm (OD)] and visual reading. The soluble antigen was prepared from the tachyzoites in mouse peritoneal cavity. A total of 1,200 swine sera from pig slaughter-house and a total of 116 swine sera from pig breeding station (S-C farm) were tested for the detection of antibodies to Toxoplasma gondii. The results obtained were summarized as follows: 1. The optimal reactions of indirect ELISA for the test sera were determined by the dilution of antigen 1:256 and 1:3,200 of horse radish peroxidase conjugate [anti-swine IgG(r)]. 2. The specific togoplasma antibody(IgG) in pigs infected with Tp artificially were detected as the serum titers of 1:64 or 1:128 at one week postinfection. 3. Of a total of 1,200 swine sera from pig slaughter-house 505 samples of sera were detected as positive (42.1%) and of a total of 116 swine sera from S-C pig breeding station 68 samples of sera as positive (58.6%). 4. The specific antibody(IgG) detection rates against a total of 1,200 test sera from pig slaughter-house were not significant between male (43.1%) and female (40.7%). 5. The indirect ELISA was proved to be a sensitive and specific procedure for the serodiagnosis of swine toxoplasmosis and also evaluated as an effective screening test for the large scale of test samples in laboratory.

• The Journal of the Korean Society for Microbiology
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• v.18 no.1
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• pp.73-85
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• 1983

The advantages of the enzyme-linked immunosorbent assay(ELISA) are its sensitivity and its simplicity in detecting IgM and IgG antibodies. For applying the ELISA to the diagnosis of typhoid fever, first of all, experiments were performed to determine which concentration of killed whole cell antigens and lipopolysaccharide(LPS) antigens of S. typhi(0.901 w) were optimally coated to the wells of the polystyrene and polyvinylchloride microplate, using the hyperimmune sera from rabbits against S. typhi. By using both kinds of antigens of S. typhi adsorbed to the ELISA microplate, the changing patterns of IgG and IgM antibodies in the sera from rabbits responding to the killed whole cell antigens of S. typhi(0901 w) during the prolonged immunization were serially traced by the ELISA. At the same time, the level of antibodies against S. typhi in sera fron patients with typhoid fever and from normal healthy persons were measured by the ELISA employing the killed whole cell antigens and LPS antigens as the coating antigens. The results obtained were summerized as follow: 1. The optimal concentration of the killed whole cell antigens, which were more easily adsorbed to the polystyrene plate than the polyvinylchloride plate, was $10^8cells/ml$ of carbonate buffer(pH. 9.6) on the wells of the polystyrene plate when treated at $37^{\circ}C$ for 4 hours. On the other hand, the optimal concentration of lipopolysaccharide antigens, which were adsorbed only to the polyvinylchloride plate, was $100{\mu}g/ml$ of carbonate buffer(pH. 9.6) on the wells of the polyvinylchloride plate when treated at $37^{\circ}C$ for 4 hours. 2. IgM antibody response were dominating in rabbits responding to the killed whole cell antigens of S. typhi(0.901 w), and were more specific to the LPS antigens than to the killed whole cell antigens in the ELISA. Good correlations were made between the IgM titers by the ELISA and the aggglutinating titers of sera from the immunized rabbits. 3. Both IgG and IgM agglutination titers by the ELISA in sera from most of patients with typhoid fever were above 1:320 but those in sera from most of normal, healthy persons were below 1:80. 4. There were close correlations between the antibody titers by the ELISA and the agglutinating titers to the killed whole cell antigens in the tested human sera, IgM titers being more correlated with the agglutinating titers than IgG titers. But a little correlations were made between the antibody titers by the ELISA and the agglutinating titers to the LPS antigens. 5. IgM titers in the tested human sera were similar to IgG titers detected by the ELISA employing the killd whole cells antigens and the LPS antigens. 6. Good correlations were made between the antibody titers demonstrated by the ELISA performed on the killed whole cell antigens and the LPS antigens as the different, coating antigens on the ELISA microplates.