• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.91-98
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• 2022

Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1672-1683
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• 2021

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla_CARB-17 gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla_CARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg²⁺, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10^-4 ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.

• The Plant Pathology Journal
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• 제38권6호
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• pp.665-672
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• 2022

Cymbidium mosaic virus (CymMV) is one of economically important viruses that cause significant losses of orchids in the world. In the present study, a reverse transcription recombinase polymerase amplification (RT-RPA) assay combined with a lateral flow immunostrip (LFI) assay was developed for the detection of CymMV in orchid plants. A pair of primers containing fluorescent probes at each terminus that amplifies highly specifically a part of the coat protein gene of CymMV was determined for RT-RPA assay. The RT-RPA assay involved incubation at an isothermal temperature (39℃) and could be performed rapidly within 30 min. In addition, no cross-reactivity was observed to occur with odontoglossum ringspot virus and cymbidium chlorotic mosaic virus. The RT-RPA with LFI assay (RT-RPA-LFI) for CymMV showed 100 times more sensitivity than conventional reverse transcription polymerase chain reaction (RT-PCR). Furthermore, the RT-PCR-LFI assay demonstrated the simplicity and the rapidity of CymMV detection since the assay did not require any equipment, by comparing results with those of conventional RT-PCR. On-site application of the RT-RPA-LFI assay was validated for the detection of CymMV in field-collected orchids, indicating a simple, rapid, sensitive, and reliable method for detecting CymMV in orchids.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7061-7069
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• 2015

Background: During the past decades, the incidence and mortality rate of stomach cancer has demonstrated a great decrease in the world, but it is still one of the most common and fatal cancers especially among men worldwide, including Iran. The MYC proto-oncogene, which is located at 8q24.1, regulates 15% of genes and is activated in 20% of all human tumors. MYC amplification and overexpression of its protein product has been reported in 15-30% of gastric neoplasias. The aim of this investigation was to find the relative efficacy of CISH (chromogenic in situ hybridization) or IHC (immunohistochemistry) in diagnosis and prognosis of gastric cancer, as well as the relationship of amplification and expression of C-MYC gene with patient survival. Materials and Methods: In this cross-sectional study, 102 samples of gastric cancer were collected from patients who had undergone primary surgical resection at the Cancer Institute Hospital, Tehran University of Medical Sciences, from July 2009 to March 2014. All samples were randomly selected from those who were diagnosed with gastric adenocarcinomas. CISH and IHC methods were performed on all of them. Results: Patients were classified into two groups. The first consisted of stage I and II cases, and the second of stage III and IV. Survival tests for both groups was carried out with referrnce to CISH test reults. Group II (stage III & IV) with CISH+ featured lower survival than those with CISH- (p=0.233), but group I (stage I & II) patients demonstrated no significant variation with CISH+ or CISH- (p=0.630). Kaplan-Meier for both groups was carried out with IHC test findings and showed similar results. This data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in men than women. Our data also showed that CISH+ patients (43%) were more frequent in comparison with IHC+ patients (14.7%). Conclusions: For planning treatment of gastric cancer patients, by focusing on expanding tumors, which is the greatest concern of the surgeons and patients, CISH is a better and more feasible test than IHC, in regard to sensitivity and specificity. Therefore, CISH can be used as a feasible test for tumor growth and prognosis in stage III and IV lesions. This study also indicated that C-MYC amplification in gastric cancer is correlated with survival in advanced stages.

• 한국축산식품학회지
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• 제33권5호
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• pp.610-616
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• 2013

본 연구에서는 영유아에게 치명적인 감염을 일으키는 C. sakazakii에 대하여 LAMP 검출법을 개발하였다. LAMP법에 의한 C. sakazakii의 검출율은 100%였으며 13개의 음성 지표군에 대해서는 모두 음성 반응을 보여 특이도가 매우 높은 것으로 판단되었다. 또한, HhaI과 NruI 두 개의 제한 효소를 LAMP product에 반응시킨 결과, 유전자의 특정 염기서열이 절단되는 것을 확인하였으며, 이를 통해 LAMP 검출법에 의해 증폭된 DNA가 C. sakazakii-specific ompA임을 확인하였다. 조제분유에 오염 된 C. sakazakii를 LAMP법으로 검출 시 검출한계는 $10^0$ CFU/mL이었으며 이는 기존의 PCR법이나 real-time PCR법에 비해 100-10,000배 높은 수준으로 민감도가 매우 높은 것으로 판단되었다. 이와 같이 높은 특이도와 민감도를 가진 LAMP 검출법은 C. sakazakii와 같은 급성 기회 감염균이나 병원성 미생물에 의한 식중독 발생시 현장에서 병원체를 간편하고 신속하게 검출할 수 있는 기술로 기대된다.

• 생명과학회지
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• 제27권7호
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• pp.746-753
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• 2017

참조기는 민어과에 속하는 우리나라의 중요한 산업 어종 중 하나이다. 최근 과도한 남획과 해양 환경의 변화로 참조기의 어획량이 줄어들자 일부 유통과정에서 유사어종인 부세, 흑조기 및 긴가이석태를 참조기로 둔갑시키는 사례가 빈번하게 발생하고 있다. 이에 본 연구에서는 종 특이 primer를 사용하여 참조기, 부세, 흑조기 및 긴가이석태를 신속하게 분석할 수 있는 방법을 마련하였다. 약 1,400 bp의 미토콘드리아 COI 유전자 분석을 통하여 종간 특이성을 나타내는 단일염기다형성 유전자를 탐색하였으며, PCR 증폭산물의 크기를 고려하여 4개의 종특이적 정방향 primer를 제작하였다. 단일 PCR을 이용한 종간 교차반응을 통하여 최적의 PCR 조건을 확립하였으며, 이후 제작된 4개의 정방향 primer를 혼합하여 4종에 대한 다중 PCR 반응을 진행하였다. 증폭된 산물은 전기영동을 통해 크기에 따라 1,540 bp, 1,013 bp, 470 bp 그리고 182 bp로 분리되었으며, 각각 참조기, 흑조기, 부세, 긴가이석태로 명확하게 판별이 가능하였다. PCR 민감도 측정에서도 모든 종에서 $0.1ng/{\mu}l$의 농도까지 검출 가능함을 확인하였다. 따라서, 본 연구에서 개발된 참조기와 유사어종에 대한 종특이 다중 PCR 분석법은 정확도와 민감도가 우수하여, 불법 유통가능성이 있는 제품에 대한 신속하고 정확한 판별로 식품안전관리에 효과적으로 활용될 것이라 사료된다.

• Animal Systematics, Evolution and Diversity
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• 제33권2호
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• pp.136-139
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• 2017

The genus Iksookimia (Actinopterygii: Cypriniformes: Cobitidae) is a bottom-dwelling freshwater loaches, which are well-known as their endemism and high geographic variation. However, population genetic relationships among Iksookimia spp. have remained unclear due to a shortage of genetic markers that can be applied generally in the genus. Here, we developed high-resolving microsatellite markers using I. koreensis and I. longicorpa as representatives of Iksookimia species because of their wide distribution range and phylogenetic position. Ten of polymorphic microsatellite loci were isolated from Iksookimia koreensis and were successfully cross-amplified in I. longicorpa. The mean number of observed alleles per locus was about 10.4 (range, 2-17) for I. koreensis and about 13.2 (range, 2-24) for I. longicorpa. The loci, IK03 and IK08, deviated from the Hardy-Weinberg equilibrium in I. koreensis, after applying the Bonferroni correction. The microsatellite markers obtained in the present study will be useful to evaluate population genetic structure and to establish conservation strategies for I. koreensis and related Iksookimia species.

• Korea-Australia Rheology Journal
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• 제20권2호
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• pp.51-58
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• 2008

This paper describes a two-step Tikhonov regularization procedure for converting the steady shear data generated by parallel-disk viscometers, in the presence of wall slip, into a shear stress-shear rate function and a wall shear stress-slip velocity functions. If the material under test has a yield stress or a critical wall shear stress below which no slip is observed the method will also provide an estimate of these stresses. Amplification of measurement noise is kept under control by the introduction of two separate regularization parameters and Generalized Cross Validation is used to guide the selection of these parameters. The performance of this procedure is demonstrated by applying it to the parallel disk data of an oil-in-water emulsion, of a foam and of a mayonnaise.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2011년도 춘계학술발표회
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• pp.242-243
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• 2011

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1279-1286
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• 2010

This paper deals with the influence on the dynamic response of I-type girder railway bridge with high-speed electric multiple unit(HEMU) train load. This bridge system which has six I-girder and several cross beams, is modeled with plate and frame elements. And the upper slab is assumed to be fully connected with girders using rigid rinks. Span lengths, types of vehicle and running speeds are selected as parameters for analyses. For more exact analysis, it was adopted that 3-dimensional section of bridge models was produced by the assumed design wheel loads of HEMU vehicle at 200~350 km/hr speeds. Dynamic vertical deflections, dynamic amplification factors and vertical accelerations of bridges having 30 and 35 m span length were investigated and compared with the limit values specified in various national railway bridge specifications.