• Journal of Genetic Medicine
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• v.12 no.2
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• pp.72-78
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• 2015

Recently, noninvasive prenatal test (NIPT) has been adopted as a primary screening tool for fetal chromosomal aneuploidy. The principle of NIPT lies in isolating the fetal fraction of cell-free DNA in maternal plasma and analyzing it with bioinformatic tools to measure the amount of gene from the target chromosome, such as chromosomes 21, 18, and 13. NIPT will contribute to decreasing the need for unnecessary invasive procedures, including amniocentesis and chorionic villi sampling, for confirming fetal aneuploidy because of its higher positive predictive value than that of the conventional prenatal screening method. However, its greater cost than that of the current antenatal screening protocol may be an obstacle to the adoption of this innovative technique in clinical practice. Digital polymerase chain reaction (dPCR) is a novel approach for detecting and quantifying nucleic acid. dPCR provides real-time diagnostic advantages with higher sensitivity, accuracy, and absolute quantification than conventional quantitative PCR. Since the groundbreaking discovery that fetal cell-free nucleic acid exists in maternal plasma was reported, dPCR has been used for the quantification of fetal DNA and for screening for fetal aneuploidy. It has been suggested that dPCR will decrease the cost by targeting specific sequences in the target chromosome, and dPCR-based noninvasive testing will facilitate progress toward the implementation of a noninvasive approach for screening for trisomy 21, 18, and 13. In this review, we highlight the principle of dPCR and discuss its future implications in clinical practice.

• Journal of the Ergonomics Society of Korea
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• v.19 no.3
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• pp.23-37
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• 2000

Usability is one of the most important factors that affect customers' decision to purchase a product. Several studies have been conducted to model the relationship between the product design variables and the product usability. Since there could be hundreds of design variables to be considered in the model, a variable screening method is required. Traditional variable screening methods are based on expert opinions (Expert screening) in most Kansei engineering studies. Suggested in this study are statistical methods for screening important design variables by using the principal component regression(PCR), cluster analysis, and partial least squares(PLS) method. Product variables with high effect (PCR screening and PLS screening) or representative variables (Cluster screening) can be used to model the usability. Proposed variable screening methods are used to model the usability for 36 audio/visual products. The three analysis methods (PCR, Cluster, and PLS) show better model performance than the Expert screening in terms of $R^2$, the number of variables in the model, and PRESS. It is expected that these methods can be used for screening the product design variables efficiently.

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.157-165
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• 2000

The efficiency of transgenic livestock production could be improved by early screening of transgene-integration and sexing of embryos at preimplantational stages before trasferring them into recipients. We examined the effciency of multiplex PCR analysis for the simultaneous confirmation of the trasgene and sex during the preimplantational development of bovine embryos and the possibility of green fluorescent protein(GFP) gene as a non-invasive marker for the early screening of transgenic embryos. The GFP gene was microinjected into the male pronuclei of bovine zygotes produced in vitro. The injected zygotes were co-cultured in TCM-199 containing 10% FCS with boving oviductal epithelial cells in a 5% CO2 incubator. Seventeen(13.0%) out of 136 gene-injected bovine zygotes developed by multiplex PCR analysis and the expression of GFP was detected by observing green fluorescence in embryos under a fluorescent microscope. Eight(67%) of 12 embryos at 2-cell to blastocyst stage were positive in the PCR analysis, but only two(11.8%) of 17 blastocysts expressed the GFP gene. Their sex was determined as 7 female and 5 male embryos by the PCR analysis. The results indicate that the screening of GFP gene and sex in bovine embryos by PCR analysis and fluorescence detection could be a promisible method for the preselection of transgenic embryos.

• Journal of Life Science
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• v.9 no.1
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• pp.14-16
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• 1999

Genetic variability was monitored by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) in dicofol-susceptible (S), dicofol-resistant (R) and its reverse-selected (RS) strains of two-spotted spider mite, of Tetranychus urticae. Before the reverse-selection, RS strain, selected reversely from R strain, was 23-fold resistance ratio at {TEX}$LC_{50}${/TEX} to S strain. The resistance was started to in incline slowly to the resistance level of S strain after one year, and the resistance ratio was 4-fold in the 7 years after then. PCR-amplification of T. urticae DNA showed polymorphism in the amplifications with 12 primers in 100 kinds of arbitrary DNA sequences. RAPD amplification with primer OPR-12 (5`-ACAGGTGCGT-3`) showed amplified bands at 1,000 base pair in the S-and RS-strain, and at 350 base pair in R-strain. The results of polymorphism are genetic variabilities derived from development and selection of resistance in each strain. The peculiarly amplified fragments were guessed to participate in dicofol resistance. From the analysis of genetic similarity, it is inferred the gene composition of S-and RS-strain is much closer than that of R-strain.

• Mycobiology
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• v.47 no.3
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• pp.350-354
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• 2019

In the post-genomic era, gene function analysis has attracted much attention. Transformation is often needed to investigate gene function. In this study, an easy, rapid, reliable, and cost-effective colony polymerase chain reaction (PCR) method for screening mushroom transformants was developed: picking up a suitable amount of transformant's tissue ($1-10{\mu}g$) to $20{\mu}l$ 0.25% Lywallzyme solution, and vortexing for 10 s followed by incubation at $34^{\circ}C$ for 15 min. Finally, $2{\mu}l$ of the suspension was used as templates to perform PCR and single target bands were successfully amplified from respective transformants of Tremella fuciformis, Pleurotus ostreatus, and Pleurotus tuber-regium. This procedure could be widely employed for screening transformants in mushroom transformation experiments.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.282-285
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• 2004

The polyene antibiotics including nystatin, pimaricin, amphotericin and candicidin are a family of most promising antifungal polyketide compounds, typically produced by rare actinomycetes species. The biosynthetic gene clusters for these polyenes have been previously investigated, revealing the presence of highly homologous biosynthetic genes among polyene-producers such as polyketide synthase (PKS) and cytochrome P450 hydroxylase (CYP) genes. Based on amino acid sequence alignment among actinomycetes CYP genes, the highly-conserved regions specific for only polyene CYP genes were identified and chosen for degenerate PCR primers, followed by the PCR-screening with various actinomycetes genomic DNAs. Among tested several polyene non-producing actinomycetes strains, Pseudonorcardia autotrophica strain was selected based on the presence of PCR product with polyene-specific CYP gene primers, and then confirmed to contain a cryptic novel polyene hydroxylase gene in the chromosome. These results suggest that the polyene-specific hydroxylase gene PCR should be an efficient way of screening and isolating potentially-valuable cryptic polyene antibiotic biosynthetic genes from various microorganisms including rare actinomycetes.

• Korean Journal of Microbiology
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• v.38 no.2
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• pp.103-106
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• 2002

Direct PCR from intact fungal cells is not readily suitable to all fungi mainly because of difficulties in rupturing the cell walls. Microwave irradiation has been proven to be useful in fungal DNA extraction protocol. Here we describe a fast template preparation method for PCR amplification from Aspefillus nidulans conidiospores using microwave irradiation. We optimized the duration far microwave irradiation, and the amount of template DNA for PCR. Amplification from samples prepared in this manner was so efficient that we could get PCR products with size enough to identify transformants. We believe that this is a time-saving procedure for screening true transformants of A. nidulans.

• BMB Reports
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• v.40 no.1
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• pp.7-14
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• 2007

Helicases are ubiquitous enzymes, which utilize the energy liberated during nucleotide triphosphate hydrolysis to separate double-stranded nucleic acids into single strands. These enzymes are very attractive targets for the development of new antibacterial compounds. The PcrA DNA helicase from Staphylococcus aureus is a good candidate for drug discovery. This enzyme is unique in the genome of S. aureus and essential for this bacterium. Furthermore, it has recently been published that it is possible to identify inhibitors of DNA helicases such as PcrA. In this report, we study the properties of recombinant PcrA from S. aureus purified from Escherichia coli to develop ATPase and helicase assays to screen for inhibitors.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.159-161
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• 2003

The coat protein (CP) gene of Apple mosaic virus (ApMV), a member of the genus Ilarvirus, was selected for the design of virus-specific primers for amplification and molecular detection of the virus in cultivated apple. A combined assay of reverse transcription and polymerase chain reaction (RT-PCR) was performed with a single pair of ApMV-specific primers and crude nucleic acid extracts from virus-infected apple for rapid detection of the virus. The PCR product was verified by restriction mapping analysis and by sequence determination. The lowest concentration of template viral RNA required for detection was 100 fg. This indicates that the RT-PCR for detection of the virus is a 10$^3$times more sensitive, reproducible and time-saving method than the enzyme-linked immunosorbent assay. The specificity of the primers was verified using other unrelated viral RNAs. No PCR product was observed when Cucumber mosaic virus (Cucumovirus) or a crude extract of healthy apple was used as a template in RT-PCR with the same primers. The PCR product (669 bp) of the CP gene of the virus was cloned into the plasmid vector and result-ant recombinant (pAPCP1) was selected for molecule of apple transformation to breed virus-resistant transgenic apple plants as the next step. This method can be useful for early stage screening of in vitro plantlet and genetic resources of resistant cultivar of apple plants.

• Parasites, Hosts and Diseases
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• v.54 no.2
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• pp.187-190
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• 2016

Trichomoniasis is the most common curable sexually-transmitted infection (STI) worldwide. There are few reports on the prevalence of Trichomonas vaginalis in Korea. The purpose of this study was to examine the prevalence of trichomoniasis by PCR in Guri city, Korea. All adult women who visited Hanyang University Guri Hospital for health screening within the National Health Care Service were invited to participate in the study, and 424 women were enrolled between March and June 2011. PCR was used to detect Trichomonas vaginalis using primers based on a repetitive sequence cloned from T. vaginalis (TV-E650). Fourteen women (3.3%) were found to have T. vaginalis. All were over 50, and they were significantly older on average than the 410 Trichomonas-negative women (mean ages 63.4 vs 55.3 years). It seems that T. vaginalis infection is not rare in women receiving health screening, especially among those over 50.