• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.129-133
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• 2007

To breed virus resistant rice variety, developing an efficient screening method is the most important. Two screening methods such as field screening and tray screening method have been used, but the efficiency of the field screening method is too low because of environment factors and the that of the tray screening method is good but screening capability is limited with only $200{\sim}300$ lines per year. To overcome those problems, mass screening method using screen house was developed. Barely as host plant of vector insect was grown in screen house in winter season. Then viruliferous insects are spread in the first spring of the initiation year and sustain them annually. Screening of virus resistance was tested two times in a year, the first screening was from April to June and the second from July to September. The virus infected rate of each susceptible varieties was increased to 92% for RSV and 100% for RDV from the second year. Also, this method can evaluate as many as $1,500{\sim}2,000$ pedigree lines in one time compared with the tray screening method. The result indicates that the mass screening method using screen house, which combines the advantages of the field and tray screening methods, is proven to be more efficient and reliable.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.337-344
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• 2011

Integrase MJ1 from the bacteriophage ${\Phi}FC1$ carries out recombination between two DNA sequences (the phage attachment site, attP and the bacterial attachment site, attB) in NIH3T3 mouse cells. In this study, the integration vector containing attP, attB and the integrase gene MJ, was constructed. The integration mediated by integrase MJ1 in Escherichia coli led to excision of LacZ. Therefore, the frequency of integration was measured by the counting of the white colony, which is detectable on X-Gal plates. The extrachromosomal integration in NIH3T3 mouse cells was monitored by the expression of the green fluorescent protein (GFP) as a reporter. To demonstrate integration mediated integrase MJ1 in NIH3T3 cells, vectors containing attP and attB were co-transfected into NIH3T3 cells. The integration was confirmed by fluorescent microscopy. The expression of GFP was induced in NIH3T3 cells expressing MJ1 without accessory factors. By contrast, the excision mediated by the MJ1 between attR and attL had no effect on the expression of GFP. These results suggest that integrase MJ1 may enable a variety of genomic modifications for research and therapeutic purposes in higher living cells.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.261-268
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• 2018

Differences in host ethnicities and geographical distributions may influence the genetic variation and pathogenesis of Helicobacter pylori strains, particularly with respect to those with a high risk of gastric cancer and in Asian Enigma regions. We simultaneously identified H. pylori virulence-associated genes involved in inflammation and cell damage in Thai and Korean dyspeptic patients. The virulence-associated gene cagA, cagA genotypes (East Asian and Western type cagA), vacA genotypes (s- and m-), oipA, and sabA were detected in Thai and Korean dyspeptic patients by polymerase chain reaction (PCR), real-time PCR, and DNA sequence analysis. Comparisons between the two regions showed that cagA, East Asian type cagA, and vacA s1/m1 in Korean dyspeptic patients occurred at rates of 100%, 86.67%, and 88.89%, respectively (p < 0.05). The oipA- and sabA-positive samples were significantly more predominant in the Korean population (95.56%, 91.11%) than in the Thai population (32%, 34%). DNA sequence analysis revealed differences in the patterns of cytosine-thymine dinucleotide repeats of oipA and sabA among the two populations of dyspeptic patients. Our results indicate that the H. pylori strains detected in the two regions were divergent, and strains colonizing the Korean dyspeptic patients may be more virulent than those in the Thai population. Our data may help explain H. pylori pathogenesis in Asian Enigma areas with a low gastric cancer incidence. However, other factors involving H. pylori infection in these two regions should be further analyzed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2613-2618
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• 2014

Aims: Dysfunction of the host immune system in cancer patients can be due to a number of factors, including lymphocyte apoptosis. Several studies showed that $Foxp3^+T$ cells take part in inducing this process by expressing FasL in tumor patients. However, the relationship between apoptosis, $CD8^+T$ cells and $Foxp3^+T$ cells in HCC patients is still unclear. The present study was designed to investigate the correlation between apoptosis levels and Fas/FasL expression in $CD8^+T$ lymphocytes and $Foxp3^+T$ cells in patients with HCC. Methods: $CD8^+T$ cells and $CD3^+Foxp3^+T$ cells were tested from peripheral blood of HCC patients and normal controls and subjected to multicolor flow cytometry. The expression of an apoptosis marker (annexin V) and the death receptor Fas in $CD8^+T$ cells and FasL in $CD3^+Foxp3^+T$ cells were evaluated. Serum TGF-${\beta}1$ levels in patients with HCC were measured by enzyme-linked immunosorbent assay. The relationship between apoptosis and Fas expression, as well as FasL expression in $CD3^+Foxp3^+T$ cells was then evaluated. Results: The frequency of $CD8^+T$ cells binding annexin V and Fas expression in $CD8^+T$ cells, were all higher in HCC patients than normal controls and the proportion of apoptotic $CD8^+T$ cells correlated with their Fas expression. Serum TGF-${\beta}1$ levels correlated inversely with $CD3^+Foxp3^+T$ cells. Conclusions: Fas/FasL interactions might lead to excessive turnover of $CD8^+T$ cells and reduce anti-tumor immune responses in patients with HCC. Further investigations of apoptosis induction in $Fas^+CD8^+T$ cells in vitro are required.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.369-378
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• 2017

Vascular endotherial growth factor (VEGF) is a potent mitogen that stimulates vascular permeability and angiogenesis and has a potential in therapeutic applications. An industrial production method that provides high yield as well as purity is needed. Researches for various factors of mild solubilization with combination of ubiquitin fusion protein to increase solubility were carried out as well as by changing pH and denaturant concentration. Usage of pET28-a bacteral expression vector in BL21 (DE3) host cell was capable of producing approximately 14 g/L VEGF fusion protein in 20L fermentor. A purification process consisting of four chromatography steps including refolding and digestion with UBP1 resulted in mild solublization under the conditions of 2M urea and pH 10.0 due to ubiquitin fusion tag protein that increases in solubility of target protein VEGF. High yield of refolding and dimerization could be obtained between two step Ni-affinity chromatography. Multimeric and misfolded proteins and endotoxin were removed by DEAE anion exchange chromatography. Final monomers were removed from dimers by gel filtration chromatography. Characterization analysis of purified dimeric VEGF was performed using SDS-PAGE and RP-HPLC with a purity of 97%.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.979-984
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• 2016

The incidence rate of stomach cancer in Bali, Indonesia, is estimated to be strikingly lower than that in Japan. We conducted an on-site ecological study to investigate the association between the stomach cancer incidence and Helicobacter pylori (H. pylori) infection. Recruiting 291 healthy persons (136 men and 155 women) from the general population in Bali, Indonesia, we conducted a urea breath test (UBT) to examine H. pylori infection, along with a pepsinogen test to detect chronic atrophic gastritis and urine analysis to estimate sodium and potassium excretion. UBT positivities were 9% (2-15, 95% confidence interval) for men and 7% (1-12) for women, and positive cases for H. pylori IgG antibodies were 1% (0-3) for men and 3% (0-5) for women, significantly lower than the respective values in Japan. Positive pepsinogen tests in Bali were 0% (0-0) for men and 1% (0-4) for women, also significantly lower than the Japanese figures. Computed values for daily salt excretion were $13.3{\pm}4.1g$ (mean${\pm}$SD) for men and $11.1{\pm}3.1g$ for women, as high as corresponding Japanese consumption values. Moreover, the estimated potassium excretion was $3.2{\pm}0.7g$ for men and $2.8{\pm}0.6g$ for women in Bali, significantly higher than the figures in Japan. There were no associations across genetic polymorphisms of IL-beta, TNF-alpha, and PTPN11 with UBT positivity. The low incidence of stomach cancer in Bali may thus mainly be due to the rare H. pylori infection. Namely, the bacterium infection seems to be a critical factor for gastric cancer rather than host or other environmental factors.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3961-3968
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• 2015

Background: Variants of human papillomavirus (HPV) show more oncogenicity than do prototypes. The HPV16 Asian variant (HPV16As) plays a major role in cervical cancer of Asian populations. Some amino acid changes in the E6 protein of HPV16 variants affect E6 functions such as p53 interaction and host immune surveillance. This study aimed to investigate activities of HPV16As E6 protein on modulation of expression of miRNA-21 as well as interferon regulatory factors (IRFs) 1, 3, 7 and c-fos. Materials and Methods: Vectors expressing E6 protein of HPV16As (E6D25E) or HPV16 prototype (E6Pro) were constructed and transfected into C33A cells. HCK1T cells expressing E6D25E or E6Pro were established by transducing retrovirus-containing E6D25E or 16E6Pro. The E6AP-binding activity of E6 and proliferation of the transfected C33A cells were determined. MiR-21 and mRNA of interesting genes were detected in the transfected C33A cells and/or the HCK1T cells, with or without treatment by culture medium from HeLa cells (HeLa-CM). Results: E6D25E showed binding activity with E6AP similar to that of E6Pro. Interestingly, E6D25E showed a higher activity of miR-21 induction than did E6Pro in C33A cells expressing E6 protein. This result was similar to the HCK1T cells expressing E6 protein, with HeLa-CM treatment. The miR-21 up-regulation significantly corresponded to its target expression. Different levels of expression of IRFs were also observed in the HCK1T cells expressing E6 protein. Interestingly, when treated with HeLa-CM, IRFs 1, 3 and 7 as well as c-fos were significantly suppressed in the HCK1T cells expressing E6D25E, whereas those in the HCK1T cells expressing E6Pro were induced. A similar situation was seen for IFN-${\alpha}$ and IFN-${\beta}$. Conclusions: E6D25E of the HPV16As variant differed from the E6 prototype in its activities on epigenetic modulation and immune surveillance and this might be a key factor for the important role of this variant in cervical cancer progression.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7645-7652
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• 2014

Neuroblastoma (NB), the most common extracranial solid tumor, accounts for 10% of childhood cancer. To date, scientists have gained quite a lot of knowledge about microRNAs (miRNAs) and their genes in NB. Discovering inner regulation networks, however, still presents problems. Our study was focused on determining differentially-expressed miRNAs, their target genes and transcription factors (TFs) which exert profound influence on the pathogenesis of NB. Here we constructed three regulatory networks: differentially-expressed, related and global. We compared and analyzed the differences between the three networks to distinguish key pathways and significant nodes. Certain pathways demonstrated specific features. The differentially-expressed network consists of already identified differentially-expressed genes, miRNAs and their host genes. With this network, we can clearly see how pathways of differentially expressed genes, differentially expressed miRNAs and TFs affect on the progression of NB. MYCN, for example, which is a mutated gene of NB, is targeted by hsa-miR-29a and hsa-miR-34a, and regulates another eight differentially-expressed miRNAs that target genes VEGFA, BCL2, REL2 and so on. Further related genes and miRNAs were obtained to construct the related network and it was observed that a miRNA and its target gene exhibit special features. Hsa-miR-34a, for example, targets gene MYC, which regulates hsa-miR-34a in turn. This forms a self-adaption association. TFs like MYC and PTEN having six types of adjacent nodes and other classes of TFs investigated really can help to demonstrate that TFs affect pathways through expressions of significant miRNAs involved in the pathogenesis of NB. The present study providing comprehensive data partially reveals the mechanism of NB and should facilitate future studies to gain more significant and related data results for NB.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.210-216
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• 1987

A computer program written to predict blast occurrence based on micro climatic events was developed and tested as an on-site microcomputer in field plots in 1984 and 1985. A microcomputer unit operating on alkaline batteries; continuously monitored air temperature, leaf wetness, and relative humidity; interpreted the microclimate information in relation to rice blast development and displayed daily values (0-8) of blast units of severity (BUS). Cumulative daily BUS values (CBUS) were highly correlated with blast development on the two susceptible cultivars, M-201 and Brazos grown in field plots. When CBUS values were used to predict the logit of disease proportions, the average coefficients of determination $(R^2)$ between these two factors were 71 to $91\%$, depending on cultivar and year. This was a significant improvement when compared to 61 to $79\%$ when days were used as a predictor of logit disease severity. The ability of CBUS to predict logit disease severity was slightly less with Brazos than M-201. This is significant inasmuch as Brazos showed field resistance at mid-sea­son. The results in this study indicate that the model has the potential for future use and that the model could be improved by incorporating other variables associated with host plants and pathogen races in addition to the key environmental variables.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.1903-1907
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• 2016

Background: Studies of effects of IL-1 polymorphisms, CYP2C19 genotype together with antibiotic resistance for H. pylori eradication are rare worldwide. The present study was designed to evaluate efficacy of 10-day sequential therapy (SQT) and 14-day standard triple therapy (STT) with four- times-daily dosing of amoxicillin for H. pylori eradication related to these important host and bacterial factors in Thailand. Materials and Methods: This prospective randomized study was performed during March 2015 to January 2016. H. pylori infected gastritis patients were randomized to receive 10-day sequential therapy and 14-day standard triple therapy. CYP2C19 genotyping, IL1 polymorphism (IL-1B and IL-1RN genotypes) and antibiotic susceptibility tests were performed in all patients. 13C-UBT was conducted to confirm H. pylori eradication at least 4 weeks after treatment. Results: A total of 100 patients (33 males and 67 females, mean age=51.1 years) were enrolled. Eradication rate by PP analysis was 97.9% (47/48) with the 10-day SQT regimen and 87.8% (43/49) with 14-day STT regimen (97.9% vs 87.8%; p-value=0.053). Antibiotic susceptibility testing demonstrated 45% resistance to metronidazole, 14.8% to clarithromycin, and 24.1% to levofloxacin. CYP2C19 genotyping revealed 44.9% RM, 49% IM and 6.1% PM. IL-1B and IL-1RN genotypes were demonstrated as 21.4% for CC, 48.1% for TC, 36.8% for TT, 72.7% for 1/1, and 21.2% for 1/2 genotypes, respectively. The 10-day SQT regimen provided 100% eradication in patients with clarithromycin or dual clarithromycin and levofloxacin H. pylori resistant strains. Moreover, the 10-day SQT regimen resulted in a 100% eradication rate in all patients with CYP2C19 genotype RM and almost type of IL-1B (TC and TT) and IL1-RN genotypes ( 1/2 and other). Conclusions: Treatment with 10-day sequential therapy is highly effective for H. pylori eradication regardless of the effects of clarithromycin resistance, dual clarithromycin and levofloxacin resistance, CYP2C19 genotype, IL-1B and IL1-RN genetic polymorphisms and can be used as effective first line therapy in Thailand.