• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.20-20
• /
• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.97-97
• /
• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• Journal of The Korean Society of Inherited Metabolic disease
• /
• v.6 no.1
• /
• pp.15-23
• /
• 2006

Purpose: Glycogen storage disease type III (GSD-III), is a rare autosomal recessive disorder of glycogen metabolism. The affected enzyme is amylo-1,6-glucosidase, 4-alpha-glucanotransferase (AGL, glycogen debranching enzyme), which is responsible for the debranching of the glycogen molecule during catabolism. The disease has been demonstrated to show clinical and biochemical heterogeneity, reflecting the genotype-phenotype heterogeneity among different patients. In this study, we analyzed mutations of the AGL gene in three unrelated Korean GSD-III patients and discussed their clinical and laboratory implications. Methods: We studied three GSD-III patients and the clinical features were characterized. Sequence analysis of 35exons and part exon-intron boundaries of the AGLgene in patients were carried out by direct DNA sequencing method using genomic DNA isolated from patients' peripheral leukocytes. Results: The clinical features included hepatomegaly (in all patients), seizures (in patient 2), growth failure (in patients 1), hyperlipidemia (in patients 1 and 3), raised transaminases and creatinine kinase concentrations (in all patients) and mild EKG abnormalities (in patients 2). Liver transplantation was performed in patient 2due to progressive hepatic fibrosis. Administration of raw-corn-starch could maintain normoglycemia and improve the condition. DNA sequence analysis revealed mutations in 5 out of 6 alleles. Patient 1 was a compound heterozygote of c.1282 G>A (p.R428K) and c.1306delA (p.S603PfsX6), patient 2 with c.1510_1511insT (p.Y504LfsX10), and patient 3 with c.3416 T>C (p.L1139P) and c.l735+1 G>T (Y538_R578delfsX4) mutations. Except R428K mutation, 4 other mutations identified in3 patients were novel. Conclusion: GSD-III patients have variable phenotypic characteristics resembling GSD-Ia. The molecular defects in the AGL gene of Korean GSD-III patients were genetically heterogeneous.

• Journal of the Institute of Convergence Signal Processing
• /
• v.16 no.2
• /
• pp.74-82
• /
• 2015

In this study, a BMW plant process control system model which produces BMW is suggested and the BMW plant process controller with the following functions is developed. The first function is to operate the electronic overload relays to stop the blower for a certain period of time and to re-operate it again when the blower is overloaded. The second function is to close the motor operated valve automatically in case of power failure to prevent the circulation from the guided tank to the compost throwing tank and to block leak from the compost throwing tank due to the failure of ball valve. The third function is to transfer produced BMW from the concentration tank to 4 storage tanks for automatic managing of the BMW output. A device to measure the signal of the BMW plant process controller and a test equipment are developed. The designed BMW plant process controller is checked to see if it operates correctly according to the design specifications. The sequence control method based on BMW plant process controller is developed at a low cost in this study, so it is expected to bring improvements in the stability and the efficiency of system and to cause reductions in the operation and the management costs in the future.

• Clinical and Experimental Reproductive Medicine
• /
• v.24 no.1
• /
• pp.57-65
• /
• 1997

Cytogenetic observations of loss of the distal portion of the Y chromosome long arm were found to be associated with disrupted spermatogenesis. The existence of a gene involved in the regulation of spermatogenesis, the azoospermia factor (AZF), was postulated. In this study, we screened the AZF region including DAZ and DAZH genes and observed the expression pattern of DAZ and DAZH transcript in infertile men with azoospermia and oligospermia by using a sequence-tagged site (STS)-based PCR method. PCR primers were synthesized for 11 STSs that span Yq interval 6, SRY, DAZ, and DAZH, functional DAZ homologue on chromosome 3. Microdeletions were detected in 4/32 (12.5%) azoospermic men and 1/11 (9%) severe oligospermic men. Only 2 of 5 patients had microdeletions of Yq that contained the DAZ gene, whereas the other 3 patients had deletions extending from intervals 5L-6F proximal to the DAZ gene on Yq. Testis biopsies of the azoospermic patients revealed a variety from Sertoli cell-only syndrome to testicular maturation arrest. Of 4 men with clinical data available, average testis size was R: 13.8 cc, L: 13.8 cc, serum T was $4.0{\pm}1.25$ ng/ml, LH was $3.63{\pm}1.90$ mIU/ml, and FSH was $8.85{\pm}5.13$ mIU/ml. These values did not differ significantly from the remainder of the patients tested. We could not observed the DAZ transcript in 2 patients, who have no mature spermatozoa. In 11.6% of patients microdeletions of the AZF could be detected. These deletions in the AZF region seem to be involved causing spermatogenic failure. But the frequency of microdeletions proximal to DAZ suggests that DAZ is not the only gene associated with spermatogenic failure.

• 대한공업교육학회지
• /
• v.33 no.2
• /
• pp.312-324
• /
• 2008

To improve the newly designed HKS(hinge kit system) in common refrigerators, it was investigated the new robust methodologies. There were the study of failure modes, mechanisms in the marketplace, and the design parameters of HKS with various improvements using accelerated life testing. Based on the claimed marketplace product returns and 1st ALT reproduction, the fracturing and cracking occur in the housing of the HKS. The missing design parameters of the failed HKS in the design phase of the refrigerator was the housing hinge kit structure. The corrective action plans are the modifications of the housing hinge kit structure from the open supporting to all supporting structure. Based on 2nd ALTs, the fracturing and cracking occur in the torsion shaft. The missing design parameter was the roundness of torsion shaft. After a sequence of ALT testing, the levels of the missing design parameters were setup. The yearly failure rate and B1 life of the redesigned HKS, based on the results of ALT, were over 0.01 percent and 10 years, respectively. The parameter design through the inspection of the failed product, load analysis, and three rounds of ALT, was very effective in the new robust design methodologies of the mechanical system and this method can be applied to other design system.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.6
• /
• pp.853-861
• /
• 2018

This paper proposes the application of harmonic constraints to address the problems caused by abnormal voltage increases when electric railway vehicles are running. The AC line that supplies the train with power during operation is used to provide electricity of 25kV/60 Hz, but gradually the size and frequency of harmonics involved in the line are varied with the technological evolution of the railroad vehicle electrical equipment. An increase in heat losses due to the failure of the instrument transformer (PT), the main circuit device, which is a serious problem with the recent train safety operation, or to the main displacement voltage. When high frequency components are introduced through low frequency Transformers of the main circuit device, the high intensity of the components is caused by the high intensity of the core and the current flow of the parasitic core is increased, thus generating heat. To solve this problem, the recent adjustment of the sequence has applied artificial NOTCH OFF of the power converter. However, the method of receiving and controlling the OFF signal operates by interaction between the ground and the vehicle's devices, thus it is invalid in the event of failure, and an actual accident is occurring. Therefore, the harmonic currents were required to prevent possible flow of harmonics, and conducted a study to prevent accidental occurrence of train accidents and to verify feasibility of the device through the simulations of the train's experimental analysis and the simulations of the train for safe operation.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.9
• /
• pp.1584-1589
• /
• 2008

Although resistance of Helicobacter pylori to clarithromycin is a major cause of failure of eradication therapies, little information is available regarding gene mutations of clarithromycin-resistant primary and secondary H. pylori isolates in Korea. In the present study, we examined gene mutations of H. pylori 238 rRNA responsible for resistance to clarithromycin. DNA sequences of the 238 rRNA gene in 21 primary clarithromycin-resistant and 64 secondary clarithromycin-resistant strains were determined by PCR amplification and nucleotide sequence analyses. Two mutations of the 238 rRNA gene, A2143G and T2182C, were observed in primary clarithromycin-resistant isolates. In secondary isolates, dual mutation of A2143G+T2182C was frequently observed. In addition, A2143G+T2182C+ T2190C, A2143G+T2182C+C2195T, and A2143G+T2182C+A2223G were observed in secondary isolates. Furthermore, macrolide binding was tested on purified ribosomes isolated from T2182C or A2143C mutant strains with $[^{14}C]$erythromycin. Erythromycin binding increased in a dose-dependent manner for the susceptible strain but not for the mutant strains. These results indicate that secondary isolates show a greater variety of 238 rRNA gene mutation types than primary isolates, and triple mutations of secondary isolates are associated with A2143G+T2182C in H. pylori isolated from Korean patients.

• Clinical and Experimental Pediatrics
• /
• v.48 no.6
• /
• pp.655-659
• /
• 2005

Esophageal duplication cysts are rare congenital lesions that occur as a result of a failure in the tubulation of the esophagus. They are most frequently single, tubular, or cystic. They may cause compressive symptoms or may be discovered incidentally on chest radiographs. They become symptomatic when complications develop. Symptoms often are related to the location of the duplication; esophageal lesions can create respiratory difficulties. The definitive diagnosis of esophageal duplication cysts requires the pathological evaluation of the cyst after surgical removal. We experienced a rare tubular esophageal duplication, in a 2-month old girl who presented with fever and grunting. This is the first reported case in which the sequence of events of ruptured tubular esophageal duplication with empyema, mediastinitis and aneurysm occured.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.22 no.3
• /
• pp.209-222
• /
• 1997

In this paper, we study a bargaining order problem where one buyer sequentially bargains with two sellers whose reservation prices are unknown to the buyer but correlated. Our main question is who the buyer should bargain first with to maximize his expected payoff. This type of problem is widely applicable to business and political situations where one party negotiates with multiple parties sequentially. One of the most important element in a sequential bargaining is "linkage effect" which exists when the aggreement of the previous bargaining affects the outcome of the following bargaining. To examine "linkage effect", we assume that the sellers'objects are similar so that the sellers' reservation prices are correlated. In addition, to consider incomplete information aspect regarding reservation prices, it is assumed that the sellers' reservation prices are unknown to the buyer. That is, we deal with one sided incomplete information case. In our model, there are two stages in each of which the buyer meets one seller. Since we are concerned with the bargaining order, we consider two different bargaining orders. Using game theory, we find a perfect Bayesian equilibrium and compute the buyer's expected payoff for each bargaining order. Finally we identify the advantageous bargaining order for the buyer by comparing the expected payoffs obtained under two different bargaining orders. Our results are as follows: the advantageous bargaining order depends on the prior probability of the seller type. However, in general, the buyer should bargain first with the seller whose object is less valuable to the buyer. The basic reason for our result is that the buyer wants to experiment in the first stage to find out the sellers' reservation prices and in doing so, to minimize the experimental cost and maximize potential gain in case of negotiation failure in the first stage. in the first stage.