• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1481-1483
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• 2010

We constructed an efficient T-vector, pTQEST216T that employed an engineered esterase as an indicator for direct cloning of PCR products. After ligation of the XcmI-digested vector with PCR products, this cloning system could easily discriminate positive clones owing to insertional inactivation of the esterase reporter. Additionally, PCR products were efficiently cloned into this vector without the gel purification steps, owing to the well-designed multi-cloning site that was in-frame fused at the circularly permutated gap of the reporter.

• BMB Reports
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• v.35 no.2
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• pp.248-250
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• 2002

Discrimination between the amplification of mRNA and contaminating genomic DNA is a common problem when performing a reverse transcriptase-polymerase chain reaction (RT-PCR). Even after treatment of the samples with DNAse, it is possible that negative controls (samples in which no reverse transcriptase was added) will give positive results. This indicates that there was amplification of DNA, which was not generated during the reverse transcriptase step. The possibility exists that Taq DNA polymerase acts as a reverse transcriptase, generating cDNA from RNA during the PCR step. In order to test this hypothesis, we incubated samples with a DNAse-free RNAse after the cDNA synthesis. Comparison of the results that were obtained from these samples (incubated with or without DNAse-free RNAse) confirms that the reverse transcriptase activity of Taq DNA polymerase I is a possible source of false positive results when performing RT-PCR from intronless genes. Moreover, we describe here a simple and rapid method to overcome the false positive results that originate by this activity of Taq polymerase.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1331-1335
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• 2000

The WL6 strain isolated from Kimchi could not be made scientific name because it was identified as three species, i.e., Leuconostoc mesenternides ssp cremoris, Leu. mesenteroides ssp. dextranicum or Lactobacillus bifermentans when it was tested by API kit or Biolog system methods. The unidentifiable WL6 strain was finally reclassified as Lactobacillus bifermentans by genetic identification using two PCR-based specific sequence primer sets which were originated from homologous pepN and 16S rRNA genes.

• Mycobiology
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• v.31 no.1
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• pp.19-22
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• 2003

The primary objective of the current research was to detect genetic variations within the Indonesian isolates of Cochliobolus heterostrophus collected from ecologically different places of the country at molecular level using PCR-RFLP analyses. The primer pair of NS3 and NS6 produced amplification fragment in all of the isolates tested. A single fragment of estimated 907 bp was observed in the PCR product pattern. RFLP analysis of the PCR product employing three restriction enzymes, HaeIII, HhaI, and RsaI, respectively, did not reveal intraspecific variations within the fungus. Similarly, nucleotide sequences of portion of small subunit of the ribosomal DNA gene of two of the isolates collected showed no appreciable differences, indicating the absence of genetic diversities among the isolates tested. A phylogenetic tree was constructed and the Indonesian C. heterostrophus, represented by SM-1 isolate, was found to be phylogenetically located near C. sativus, a closely related species.

• Genomics & Informatics
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• v.6 no.2
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• pp.84-86
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• 2008

The Tetrahymena group I intron has been shown to employ a trans-splicing reaction and has been modified to specifically target and replace human telomerase reverse transcriptase (hTERT) RNA with a suicide gene transcript, resulting in the induction of selective cytotoxicity in cancer cells that express the target RNA, in animal models as well as in cell cultures. In this study, we evaluated the target RNA specificity of trans-splicing phenomena by the group I intron in mice that were intraperitoneally inoculated with hTERT-expressing human cancer cells to validate the anti-cancer therapeutic applicability of the group I intron. To this end, an adenoviral vector that encoded for the hTERT-targeting group I intron was constructed and systemically injected into the animal. 5'-end RACE-PCR and sequencing analyses of the trans-spliced cDNA clones revealed that all of the analyzed products in the tumor tissue of the virus-infected mice resulted from reactions that were generated only with the targeted hTERT RNA. This study implies the in vivo target specificity of the trans-splicing group I intron and hence suggests that RNA replacement via a trans-splicing reaction by the group I intron is a potent anti-cancer genetic approach.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.371-376
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• 2012

Background: Caveolin-1 (CAV-1), encoding the structural component of cellular caveolae, is a suggested tumor suppressor gene involved in cell signalling. Aberrant promoter methylation of CAV-1 is associated with inactivation of expression. We previously observed CAV-1 mutations in breast cancers and therefore devised this study to examine the hypermethylation status of the promoter region of CAV-1 with reference to breast cancer progression and development. Methods: Hypermethylation status of CAV-1 was analyzed by methylation specific PCR. Loss of expression of the CAV-1 gene was further evaluated by semi-quantitative rt-PCR. Results: 28/130 (21.5%) breast cancer cases showed promoter hypermethylation with reduced CAV-1 expression levels when compared with adjacent normal breast tissue. CAV-1 gene hypermethylation was significantly related to menopausal status, histopathological grade and age. Conclusion: The rationale of our study is that CAV-1 gene is transcriptionally repressed in breast cancer cells due to hypermethylation. Our results reveal that promoter hypermethylation and loss of expression of the CAV-1 gene is an important alternative mechanism for inactivation of CAV-1 leading to complete gene silencing.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.91-98
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• 1996

벼도열병균 14개 균주와 벼 이외 화본과 식물 도열병균 12개 균주를 대상으로 rDNA의 ITS II 부위를 증폭하여 그들의 핵산 구조 차이를 분석함으로 도열병균 균주간 분류를 시도하였다. 5.8S rDNA의 3`-말단 부위와 28S rDNA의 5`-말단 부위의 sequence 중 5`-CCCGGGAATTCGCATCGATCGATCGAATGAAGA-ACGCAGC-3`와 5`-CCCGGGATCCTCCGCTTATT-GATATGC-3`를 이용하여 PCR 증폭을 하였을 때 벼도열병균 14개 균주는 동일한 길이의 단일 밴드를 형성하였으며 벼 이외 화본과 식물 도열병균에서는 레드톱 식물로부터 분리한 도열병균만이 나머지 균주보다 38bp가 더 큰 길이를 가진 밴드를 형성하였다. PCR로 증폭된 DNA를 HaeIII와 MspI 제한효소로 절단하였을 때 벼도열병균 레이스간에는 제한효소 절단에 의한 전기영동 밴드 형태 차이를 관찰할 수 없었으나, 벼 이외 화본과 식물 도열병균 12개 균주는 3군으로 구분할 수 있었다. 벼도열병균 90=054와 강아지풀에서 분리한 도열병균 G90-5, 기장에서 분리한 G88-4, 바랭이에서 분리한 G88-5 그리고 레드톱에서 분리한 RT 균주의 ITS II 부위의 DNA 염기서열 비교 분석에 의하면 G88-4와는 다른 HaeIII와 MspI 제한효소 위치를 가지고 있었기에 제한효소 절단에 의한 전기영동 형태가 상이하였다. 또한 RT균주는 HaeIII와 MspI위치가 존재하지 않았다.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.323-332
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• 2017

Homology-specific transcriptional and post-transcriptional silencing, an intrinsic mechanism of gene regulation in most eukaryotes, can be induced by anti-sense, co-suppression, or hairpin-based double-stranded RNA. Hairpin-based RNA interference (RNAi) has been applied to analyze gene function and genetically modify crops. However, RNAi vector construction usually requires high-cost cloning steps and large amounts of time, or involves methods that are protected by intellectual property rights. We describe a more effective method for generating intron-spliced RNAi constructs. To produce intron-spliced hairpin RNA, an RNAi cassette was ligated with the first intron and splicing sequences of the Brassica rapa ssp. pekinensis histone deacetylase 1 gene. This method requires a single ligation of the PCR-amplified target gene to SpeI-NcoI and SacI-BglII enzyme sites to create a gene-specific silencing construct. We named the resulting binary vector system pKHi and verified its functionality by constructing a vector to silence DIHYDROFLAVONOL 4-REDUCTASE (DFR), transforming it into tobacco plants, and confirming DFR gene-silencing via PCR, RT-qPCR, and analysis of the accumulation of small interfering RNAs. Reduction of anthocyanin biosynthesis was also confirmed by analyzing flower color of the transgenic tobacco plants. This study demonstrates that small interfering RNAs generated through the pKHi vector system can efficiently silence target genes and could be used in developing genetically modified crops.

• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.12-20
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• 2008

Validation of viral safety is essential in ensuring the safety of mammalian cell culture-derived biopharmaceuticals, because numerous adventitious viruses have been contaminated during the manufacture of the products. Mammalian cells are highly susceptible to minute virus of mice(MVM), and there are several reports of MVM contamination during the manufacture of biopharmaceuticals. In order to establish the validation system for the MVM safety, a real-time PCR method was developed for quantitative detection of MVM in cell lines, raw materials, manufacturing processes, and final products as well as MVM clearance validation. Specific primers for amplification of MVM DNA was selected, and MVM DNA was quantified by use of SYBR Green I. The sensitivity of the assay was calculated to be $6{\times}10^{-2}TCID_{50}/mL$. The real-time PCR method was proven to be reproducible and very specific to MVM. The established real-time PCR assay was successfully applied to the validation of Chinese hamster ovary (CHO) cell artificially infected with MVM. MVM DNA could be Quantified in CHO cell as well as culture supernatant. When the real-time PCR assay was applied to the validation of virus removal during a virus filtration process, the result was similar to that of virus infectivity assay. Therefore, it was concluded that this rapid, specific, sensitive, and robust assay could replace infectivity assay for detection and clearance validation of MVM.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1134-1139
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• 2002

Campylobacter, Arcobacter, and Helicobacter, classified into the same rRNA superfamily VI by taxonomy, cause food-borne diseases, stomach ulcer, and gastric cancer. To detect each strain selectively from contaminated foods, PCR, multiplex-PCR, and restricion fragment length polymorphism (RFLP) were applied on Campylobacter, Arcobacter, and Helicobacter. The same PCR products could be detected using CHA primer targeted for 16S rRNA of Campylobacter, Arcobacter, and Helicobacter. To detect C. jejuni and C. coli from A. butzleri and H. pylori, pg50/pg3 primer targeted for fla A gene was used, and for A. butzleri, Arco2/Butz primer targeted for 23S rRNA was utilized. For H. pylori detection, icd1/icd2 primer targeted for isocitrate dehydrogenase gene was employed, and JEJ1/JEJ2 primer targeted for ceuE gene was effective for C. jejuni detection from the three strains. C. jejuni, C. coli could be separated from A. butzleri and H. pylori through PCR-RFLP using restriction enzyme Dde I. Such primers would be effective for detecting each strain selectively through PCR when C. jejuni, C. coli, A butzleri and H. pylori are contaminated together.