• Korean Journal of Microbiology
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• v.15 no.4
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• pp.145-153
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• 1977

Penicillin amidase (EC 3.5.1.11) was produced by a mutant strain of Bacillius megaterium ATCC 14945. Hydroxylamine assay method for the determination of 6-APT was modified by using "HCl addition techniques" in order to simplify the time consuming orginal assay method without sacrifice of accuracy. Using the new mutant strain, the effects of fermentation conditions on enzyme production were studied.e studied.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1009-1014
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• 2000

In order to detect pantothenic acid (PA), conditions for enzyme-linked immunosorbent assay (ELISA) were established. Anti-PA-BSA antibody was produced from rabbits immunized with PA-bovine serum albumin (BSA) conjugates which were prepared by the bromoacetyl chloride [Bc] method (PA-BSA[Bc]) and by the periodate oxidation [Po] method (PA-BSA[Po]). PA-BSA[Bc] and PA-BSA[Po] was used as a coating antigen for competitive indirect(ci)ELISA. The Anti-PA-BSA[Po] antibody on ciELISA showed no competitive reaction. The detection limit of PA by ciELISA using Anti-PA-BSA[Bc] antibody was 1 ppm. The Anti-PA-BSA[Bc] antibody showed little cross-reactivity to PA derivatives such as pantoyllactone, pantetheine, pantothenyl alcohol, and acetyl CoA. The detection limit of PA by microbiological assay (MBA) was 10 ppb. Assay recoveries of PA in egg, cow's liver, and lettuce by ciELISA were 109, 64, and 344%, respectively, comparing with the MBA results.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1273-1278
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• 1998

Conditions for enzyme-protein binding assay (EPBA) were established in order to detect biotin more rapidly and reproducibly than traditional microbiological assay (MBA). EPBA with streptavidin and biotin-KLH conjugate showed cross-reactivities on biocytin, a derivative with biotin activity, at the rate of 109% $(IC_{50}=0.3\;ppb)\;and\;197%\;(IC_{50}=0.8\;ppb)$, respectively, but not on other derivatives with no biotin activities, such as desthiobiotin, diaminobiotin and 2-iminobiotin. Detection ranges of biotin by EPBA with streptavidin and biotin-KLH conjugates were $0.01{\sim}30\;ng/mL\;and\;0.01{\sim}1.0\;ng/mL(ppb)$, respectively. In the spike test with milk, fruit flake and pine-carrot juice, the correlation coefficience between MBA and EPBA with biotin-KLH conjugates was r=0.994. But MBA showed cross-reactivities both on biocytin and desthiobiotin at the rate of 80.1% and 66.7%, respectively. Detection range of biotin by MBA was $0.1{\sim}0.5\;ng/mL(ppb)$. These results strongly suggest that EPBA is efficient for biotin detection in sensitivity, detection range, cross-reactivity and time consuming.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.358-367
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• 2021

The World Health Organization (WHO) has declared the coronavirus disease 2019 (COVID-19) as an international health emergency. Current diagnostic tests are based on the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method, which is the gold standard test that involves the amplification of viral RNA. However, the RT-qPCR assay has limitations in terms of sensitivity and quantification. In this study, we tested both qPCR and droplet digital PCR (ddPCR) to detect low amounts of viral RNA. The cycle threshold (CT) of the viral RNA by RT-PCR significantly varied according to the sequences of the primer and probe sets with in vitro transcript (IVT) RNA or viral RNA as templates, whereas the copy number of the viral RNA by ddPCR was effectively quantified with IVT RNA, cultured viral RNA, and RNA from clinical samples. Furthermore, the clinical samples were assayed via both methods, and the sensitivity of the ddPCR was determined to be equal to or more than that of the RT-qPCR. However, the ddPCR assay is more suitable for determining the copy number of reference materials. These findings suggest that the qPCR assay with the ddPCR defined reference materials could be used as a highly sensitive and compatible diagnostic method for viral RNA detection.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.204-210
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• 1993

The distribution and excretion of DWC-751, a new cephalosporin, were examined in rats and mice following a single intravenous administration. DWC-751 in plasma and urine was determined by both HPLC and microbiological assay. The plasma concentration of the drug declined biexponentially. The initial and terminal half lives of the drug were 3.0 and 28.3 min, respectively. Binding of the drug to plasma proteins was 42.3%. The distribution volume at steacly-state ($Vd_{ss}$) was only 0.341 ι/kg, which is well correlated with the low n-octanol/water partition coefficient of the drug ($K_{o/w{\cong}0$) Actually, the drug was distributed to liver, kidney and lung with very low organ/plasma concentration ratio. The drug, was excreted mainly via renal excretion, i.e., the total($CL_T$) and apparent renal($CL_{R}$) clearances of the drug were 10.8 and 7.5 ml/min/kg, respectively.

• The Korean Journal of Mycology
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• v.8 no.1
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• pp.69-71
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• 1980

To establish a competent method of microbiological assay for bacampicillin, one of new semi-synthetic derivatives of ${\beta}-lactam$ antibiotics, a comparison was carried out between different conditions for hydrolysis of bacampicillin into ampicillin which was then subjected to cylinder plate method. The results showed that the use of carboxylic ester hydrolase in vitro as a pretreatment of it in either pH value 6 or 8 was feasible and that the cylinder plate method with Sarcina lutea was adequate for potency estimation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.381-385
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• 2004

This study was conducted to develop an HPLC method for determining pantothenic acid in fortified foods which has typically been determined by microbiological assay (MBA) according to AOAC and Korean Food Code approved methods. Pantothenic acid was determined by reversed-phase ion-pair HPLC using UV absorption (200 nm) after extraction with 20 mM potassium phosphate solution by sonication. The recovery of spiked samples and detection limit (LOD) by HPLC were 83.5∼109.6% and 0.5 ppm (mg/kg), respectively. The LOD of the microbiological assay (MBA) was much lower than that of HPLC. The concentrations of pantothenic acid analyzed in all tested samples (n=13) confirmed compliance with declared label claims. The range of recovery ratio by the HPLC method when compared to the microbiological assay was 91.9∼117.6%. There was not significant difference (p<0.01) between the HPLC and MBA methods and the equation of the regression curve was y=1.1428x-0.2269 (r=0.9842). This proposed HPLC method for determining pantothenic acid appears to be suitable for determining pantothenic acid concentrations above 0.25 mg/100 g in fortified foods.

• Journal of Microbiology
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• v.38 no.2
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• pp.74-79
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• 2000

For the demonstration of a novel riboflavin kinase assay method based on the bacterial bioluminescence, partially purified riboflavin kinase was prepared from bovine liver through ammonium sulfate precipitation and DEAE-cellulose ion exchange chromatography. Using bacterial luciferase from Photobacterium phosphoreum and the dithionite reduction method, and easy, safe, and fast assay method was established. The optimal temperature, pH, Km values form riboflavin and ATP of boving liver riboflavin kinase determined with this luminescence method were 35$^{\circ}C$, pH 7, 15.3${\mu}$M and 8.3.${\mu}$M, respectively. The detection limit of FMN produced by riboflavin kinase was in the range of 200 pM to 4${\mu}$M which is comparable to the HPLC-fluorescence detection method, while the detection time for each assay was less than 15 sec compared to the HPLC method which requeires at least 10 min for completion.

• Journal of Microbiology
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• v.40 no.2
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• pp.146-150
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• 2002

A multiplex polymerase chain reaction (PCR) assay was developed for the identification of two Candida species-albicans and dubliniensis. Three sets of primers were selected from different genomic sequences to specifically amplify a 516 bp fragment within the tops gene, specific for several species of the genus Candida (CCL primers); a 239 bp fragment within the $\alpha$INT1 gene, specific for Candida albicans (CAL primers); and a 175 bp fragment within the ALSD1 gene, specific for Candida dubliniensis (CDL primers). Using the primers in conjunction (multiplex PCR), we were able to detect both C. albicans and C. dubliniensis and to differentiate between them. The detection limit of the PCR assay was approximately 10 cells per milliliter of saline. Thus, this multiplex PCR assay can be applied for differentiation of C. albicans and C. dubliniensis from clinical specimens.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.387-390
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• 2003

The microbiological stability was examined by detecting the growth of microorganisms in the closed bottles under anaerobic long-term storage at $25^{\circ}C$ and 35$^{\circ}C$. Microbial growth was examined by a microscope and total cell number on a plate medium was quantitatively measured. There was no observed microbial growth in biodiesel for 90 days.