• 미생물학회지
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• 제46권1호
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• pp.96-103
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• 2010

단백질의 N-글리코실화는 대표적인 번역 후 변형 중의 하나로 진핵생물 뿐 아니라 원핵생물에서도 발견된다. N-글리코실화는 단백질 상의 N-글리코실 서열인 N-x-S/T 위치에 지질과 연결된 올리고당(lipid-linked oligosaccharide, LLO)으로부터 올리고당 전이효소(oligosaccharyltransferase, OTase) 활성에 의해 글리칸(glycan)이 전달되어 당단백질의 합성이 이루어진다. 본 연구에서는 OTase의 세포내 활성을 측정하기 위하여 5/6-carboxyltetramethylrhodamine (TAMRA)이 도입된 형광펩타이드 TAMRA-DA$\underline{N}$Y$\underline{T}$K-$NH_2$를 이용하였다. OTase활성 측정은 단일 서브유닛으로 효소의 활성을 갖는 운동핵 편모충류인 Leishmania major Stt3p와 병원성 미생물인 Campylobacter jejuni PglB를 진핵생물과 원핵생물의 모델 효소로 각각 사용하여 Saccharomyces cerevisiae와 C. jejuni 유래 LLO와 형광 펩타이드를 반응시켜 당-펩타이드를 합성하였다. 합성된 당-펩타이드를 미반응한 형광펩타이드와 분리 및 당-펩타이드의 정량 분석을 위하여 Tricine SDS-PAGE, ConA 렉틴 컬럼 및 fluorospectrophotometer, HPLC를 사용하였으며, 당-펩타이드 분석을 통해 각 방법의 장단점을 비교하였다. 비교 분석 결과 Tricine SDS-PAGE를 이용한 형광 이미지 분석과, 렉틴 컬럼을 통해 분리된 당-펩타이드의 fluorospectrophotometer 정량법에 비해, HPLC를 이용한 방법이 OTase에 의해 생성된 당-펩타이드를 분석하는데 더 정확하고 정량적인 값을 제시하는 것으로 확인되었다.

• Journal of Veterinary Science
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• 제22권4호
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• pp.56.1-56.10
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• 2021

Background: Fluorescent antibody virus neutralization (FAVN) test is a standard assay for quantifying rabies virus-neutralizing antibody (VNA) in serum. However, a safer rabies virus (RABV) should be used in the FAVN assay. There is a need for a new method that is economical and time-saving by eliminating the immunostaining step. Objectives: We aimed to improve the traditional FAVN method by rescuing and characterizing a new recombinant RABV expressing green fluorescent protein (GFP). Methods: A new recombinant RABV expressing GFP designated as ERAGS-GFP was rescued using a reverse genetic system. Immuno-fluorescence assay, peroxidase-linked assay, electron microscopy and reverse transcription polymerase chain reaction were performed to confirm the recombinant ERAGS-GFP virus as a RABV expressing the GFP gene. The safety of ERAGS-GFP was evaluated in 4-week-old mice. The rabies VNA titers were measured and compared with conventional FAVN and FAVN-GFP tests using VERO cells. Results: The virus propagated in VERO cells was confirmed as RABV expressing GFP. The ERAGS-GFP showed the highest titer (10^8.0 TCID₅₀/mL) in VERO cells at 5 days post-inoculation, and GFP expression persisted until passage 30. The body weight of 4-week-old mice inoculated intracranially with ERAGS-GFP continued to increase and the survival rate was 100%. In 62 dog sera, the FAVN-GFP result was significantly correlated with that of conventional FAVN (r = 0.95). Conclusions: We constructed ERAGS-GFP, which could replace the challenge virus standard-11 strain used in FAVN test.

• Annals of Laboratory Medicine
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• 제39권1호
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• pp.50-57
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• 2019

Background: The Automated Fluorescent Immunoassay System (AFIAS) rotavirus assay (Boditech Med Inc., Chuncheon, Korea) is a new rapid antigen test for rotavirus detection. We evaluated the performance of this assay for detecting rotaviruses and their specific genotypes in clinical stool samples. Methods: AFIAS rotavirus assay was performed in 103 rotavirus-positive and 103 rotavirus-negative stool samples (confirmed by both PCR and ELISA), and its results were compared with those of PCR, ELISA, and immunochromatographic assay (ICA). We evaluated diagnostic sensitivity/specificity, the detectability of rotavirus subtypes, lower limit of detection (LLOD), reproducibility, cross-reactivity, and interference of AFIAS rotavirus assay. Results: Based on PCR and ELISA results, diagnostic sensitivity and specificity of the AFIAS rotavirus assay were both 99.0%. LLOD results showed that the AFIAS assay had sensitivity similar to or greater than ICA and ELISA. High reproducibility was confirmed, and no cross-reactivity or interference was detected. This assay could detect genotypes G1P[8], G2P[4], G3P[8], G4P[6], G4P[8], G8P[4], G8P[8], G9P[4], and G9P[8]. Conclusions: The AFIAS rotavirus assay showed high reproducibility, sensitivity, and specificity as well as excellent agreement with ELISA, PCR, and ICA. It detected the most common as well as unusual genotypes of rotavirus prevalent in Korea. It could be a useful onsite assay for rapid, convenient, and cost-effective detection of rotavirus infection.

• 대한의생명과학회지
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• 제16권4호
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• pp.279-285
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• 2010

Endogenous cannabinoids (endocannabinoids) display various pharmacological effects including pain control, anti-inflammation, and neuroprotection. The synthesis and release of endocannabinoids are regulated under both physiological and pathological conditions. The main degrading enzyme of endocannabinoid is fatty acid amide hydrolase (FAAH). Therefore we have developed the fluorescence-based assay system for FAAH. We established stable CosM6 cell lines expressing human FAAH. We also synthesized 2-oxo-2H-chromen-7-yl decanoate (DAEC) as a fluorogenic substrate for FAAH. When crude membrane extracts stably expressing FAAH was incubated with DAEC at $25^{\circ}C$, FAAH reacted specifically to DAEC and catalyzes the hydrolysis of DAEC into decanoic acid and highly fluorescent coumarin. Furthermore, the serin hydrolase inhibitor, phenylmethanesulfonylfluoride, inhibited the coumarin release to the reaction buffer in concentration dependent manner. This assay system is suitable for high-throughput screening since this system has simple experimental procedure and measurement method.

• Parasites, Hosts and Diseases
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• 제60권3호
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• pp.201-205
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• 2022

Babesia microti is one of the most common causative agents of babesiosis. A sensitive and rapid detection is necessary for screening potentially infected individuals. In this study, B. microti cytochrome c oxidase subunit I (cox1) was selected as the target gene, multiple primers were designed, and optimized by a recombinase-aided amplification (RAA) assay. The optimal primers and probe were labeled with fluorescein. The sensitivity of fluorescent RAA (fRAA) was evaluated using gradient diluents of the cox1 recombinant plasmid and genomic DNA extracted from whole blood of B. microti infected mice. The specificity of fRAA was assessed by other transfusion transmitted parasites. The analytical sensitivity of the fRAA assay was 10 copies of recombinant plasmid per reaction and 10 fg/µl B. microti genomic DNA. No cross-reaction with any other blood-transmitted parasites was observed. Our results demonstrated that the fRAA assay would be rapid, sensitive, and specific for the detection of B. microti.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1269-1274
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• 2014

Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.

• International Journal of Industrial Entomology and Biomaterials
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• 제1권1호
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• pp.19-23
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• 2000

A novel recombinant baculovirus Autographa californica nuclear polyhedrosis virus (ACNPV) producing the green fluorescent polyhedra was constructed and characterized. The recombinant virus was stably produced fluorescent polyhedra in the infected cells and the morphology of the polyhedra was nearly similar to that of wild-type AcNPV. For the production of the fluorescent polyhedral the green fluorescent protein (GFP) gene was introduced under the control of polyhedrin gene promoter of AcNPV by translational fusion in the front and back of intact polyhedrin gene. The recombinant baculovirus was named as CXEP, As expected, the 93 kDa fusion protein was expressed in the CXEP-infected cells. Interestingly, however, the cells infected with CXEP also showed a 33 kDa protein band as cells infected with wild-type AcNPV. The results of Southern blot analysis and plaque assay suggested that two types of baculoviruses expressing the GFP fusion protein or only native polyhedrin were formed through homologous recombination between two polyhedrin genes in the same orientation. Thus, this system can be applied for the production of recombinant polyhedra with foreign gene product of diverse interest.

• Environmental Engineering Research
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• 제23권3호
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• pp.282-287
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• 2018

Three different methods of bacterial viability monitoring were compared to detect chemically or thermally inactivated Escherichia coli. Direct colony enumeration, live/dead bacterial cell staining with a fluorescent dye, and the dehydrogenase activity assay were compared with respect to their ease of use and time required to perform the three different tests. The green (live cell)/red (dead cell) ratio obtained from the fluorescent bacterial cell staining approach showed a linear relationship with the colony forming units; the result obtained with dehydrogenase was similar to those. The sensitivity of the monitoring methods to detect bacterial deactivation varied with different disinfection conditions. After thermal treatment, the sensitivity of the staining approach was lower, while that of the dehydrogenase activity assay was the highest. After chemical treatment, the sensitivity of detection for both methods was similar.

• Journal of Veterinary Science
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• 제21권4호
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• pp.68.1-68.8
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• 2020

A fluorescent microsphere-based immunochromatographic strip test (FICT) was developed for the rapid, sensitive, and quantitative detection of porcine reproductive and respiratory syndrome virus (PRRSV) antibodies at the pen-side. The assay was based on the formation of a sandwich immune-complex (anti-pig IgG-PRRSV antibodies-NSP7/N), which was validated by a comparison with IDEXX-ELISA using 3325 clinical specimens. The diagnostic specificity, sensitivity, and accuracy of FICT were 97.28, 93.41, and 94.95%, respectively. FICT showed a good correlation with the virus neutralization assay. Overall, a promising pen-side diagnostic tool was developed for the rapid and quantitative detection of PRRSV antibodies within 15 min.

• Bulletin of the Korean Chemical Society
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• 제11권1호
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• pp.54-58
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• 1990

Acid-base equilibria and spectroscopic properties of diazepam and chlorodiazepoxide were investigated in sodium dodecyl sulfate (SDS) micellar solutions as functions of pH. The results were compared with the behaviors in homogeneous aqueous media. The presence of SDS increased the $pK_a$ of chlorodiazepoxide to 6.3 from 4.7, while it has little effect on the $pK_a$ of diazepam. The acidic protonated form of diazepam was moderately fluorescent when the solution was excited at 350 nm, and emissnion intensity of the species was enhanced about 5 fold by the presence of SDS. On the other hand, the acidic solution of chlorodiazepoxide was non-fluorescent, but the neutral solution of the compound was fluorescent upon excitation at 350 nm. The emission peak of the neutral chlorodiazepoxide shifted to shorter wavelength region without significant change in the emission intensity upon the addition of SDS. Procedures for assay of the individual drugs from their mixture by the use of SDS micelle were discussed.