• Journal of Microbiology and Biotechnology
• /
• v.23 no.3
• /
• pp.304-312
• /
• 2013

The thermotolerant methylotrophic yeast Hansenula polymorpha is attracting interest as a potential strain for the production of recombinant proteins and biofuels. However, only limited numbers of genome engineering tools are currently available for H. polymorpha. In the present study, we identified the HpPOL3 gene encoding the catalytic subunit of DNA polymerase ${\delta}$ of H. polymorpha and mutated the sequence encoding conserved amino acid residues that are important for its proofreading 3'${\rightarrow}$5' exonuclease activity. The resulting $HpPOL3^*$ gene encoding the error-prone proofreading-deficient DNA polymerase ${\delta}$ was cloned under a methanol oxidase promoter to construct the mutator plasmid pHIF8, which also contains additional elements for site-specific chromosomal integration, selection, and excision. In a H. polymorpha mutator strain chromosomally integrated with pHIF8, a $URA3^-$ mutant resistant to 5-fluoroorotic acid was generated at a 50-fold higher frequency than in the wild-type strain, due to the dominant negative expression of $HpPOL3^*$. Moreover, after obtaining the desired mutant, the mutator allele was readily removed from the chromosome by homologous recombination to avoid the uncontrolled accumulation of additional mutations. Our mutator system, which depends on the accumulation of random mutations that are incorporated during DNA replication, will be useful to generate strains with mutant phenotypes, especially those related to unknown or multiple genes on the chromosome.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.5
• /
• pp.1999-2002
• /
• 2012

Background: DNA polymerase is a single-copy gene that is considered to be part of the DNA repair machinery in mammalian cells. The encoded enzyme is a key to the base excision repair (BER) pathway. It is evident that pol beta has mutations in various cancer samples, but little is known about ovarian cancer. Aim: Identification of any variant form of $pol{\beta}$ cDNA in ovarian carcinoma and determination of association between the polymorphism and ovarian cancer risk in Indian patients. We used 152 samples to isolate and perform RT-PCR and sequencing. Results: A variant of polymerase beta (deletion of exon 4-6 and 11-13, comprising of amino acid 63-123, and 208-304) is detected in heterozygous condition. The product size of this variant is 532 bp while wild type pol beta is 1 kb. Our study of association between the variant and the endometrioid type shows that it is a statistically significant factor for ovarian cancer [OR=31.9 (4.12-246.25) with p<0.001]. The association between variant and stage IV patients further indicated risk (${\chi}^2$ value of 29.7, and OR value 6.77 with 95% CI values 3.3-13.86). The correlation study also confirms the association data (Pearson correlation values for variant/stage IV and variant/endometrioid of 0.44 and 0.39). Conclusion: Individuals from this part of India with this type of variant may be at risk of stage IV, endometrioid type ovarian carcinoma.

• Molecules and Cells
• /
• v.26 no.4
• /
• pp.404-408
• /
• 2008

The genome of replication-competent BERV ${\gamma}4$ provirus, which is the most abundant ERV family in the bovine genome, was characterized in detail. The BERV ${\gamma}4$ genome showed that BERV ${\gamma}4$ harbors 8576 nucleotides and has the typical 5'-long terminal repeat (LTR)-gag-pro-pol-env-LTR-3' retroviral organization with a long leader region positioned before the gag open reading frame. Multiple sequences analysis showed that the nucleotide difference between 5' and 3' LTRs was 4.2% (mean value 0.042) in average, suggesting that the provirus formed at most 13.3 million years ago. Gag separated by a stop codon from pro-pol in the same reading frame, while env resides in another reading frame lacking of a functional surface domain. According to the current bovine genome sequence assembly, the full-length BERV ${\gamma}4$ provirus sequences were only found in the chromosomes 1, 2, 6, 10, 15, 23, 26, 28, X, and unassigned, although the partial sequences almost evenly distributed in the entire bovine genome. This is the first detailed study describing the genome structure of BERV ${\gamma}4$, the most abundant ERV family present in bovine genome. Combined with our recent reports on characterization of ERVs in bovine, this study will contribute to illuminate ERVs in the cattle of which no information was previously available.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09a
• /
• pp.591-594
• /
• 2003

In this paper, we propose a method to avoidance obstacle in which we assume that obstacle has an unstable limit cycle in the chaos trajectory surface. In order to avoid the obstacle, we assume that all obstacles in the chaos trajectory surface in which has an unstable limit cycle with Van der Pol equation. In this paper show also that computer simulation results are satisfy to avoid obstacle in the chaos trajectory with Chua's circuit equation of one or multi obstacle has an limit cycle with Van der Pol (VDP) efuation and compare to rate of cover in one robot which have random walk and Chua's equation.

• Restorative Dentistry and Endodontics
• /
• v.7 no.1
• /
• pp.101-106
• /
• 1981

The purpose of this study was to estimate the ability of the marginal fit of Glass ionomer cement. Using the human extracted teeth and 2% acqueous solution of methylene blue, the author investigated the marginal penetration of dye in restorative materials such as Amalgam, Hi-Pol, Glass ionomer cement, Estic microfill and Restodent. The results were as follows. 1. All filling materials showed some degree of marginal penetration. 2. Glass ionomer cement revealed nearly the same microleakage as Estic microfill and Hi-Pol, but showed inferior effect of the marginal seal as compared with Restodent. 3. It is appeared that Amalgam has more effective ability of the marginal fit than the others within a week.

• Korean journal of applied entomology
• /
• v.35 no.4
• /
• pp.315-320
• /
• 1996

The effects of 2-arnino-3-methyIimidazo[4,5-fq]u inoline (IQ), 2-amino-6dimethyl-dipyrido[l,2-a;3',2'-d] imidazole (Glu-P-1) and aflatoxin B1 (AFBI) on the mitotic recombinations and somatic chromosome mutations were investigated using the transgenic Drosophila bearing a chimeric gene consisting of a promoter region of Drosophila actin 5C gene and rat DNA polymerase $. For investigating mitotic recombinations and the somatic chromosome mutations, the heterozygous (mwhl+) strain possessing or lacking transgene pol P was used. The spontaneous frequency of small mwh spots, due to deletion or nondisjunction etc., in the non-transgenic w strain and the transgenic plpol $1-130 strain was 0.351 and 0.606, respectively. The spontaneous frequency (0.063) of large mwh spots, arising mostly from somatic recombination between the centromere and the locus mwh, in the transgenic plpol $1-130 strain, was about three times higher than that (0.021) of the non-transgenic w strain. The mutant clone frequencies of two types induced by two heterocyclic mines (IQ and Glu-P-1) and AFBl in the transformant pbol PI-130 were two or three times higher than those in the host strain w. These mean that rat DNA polymerase P participates at least in the somatic chromosome mutations and mitotic recombination processes. And the present results suggest that the transgenic Drosophl!~ used in this study can be used as a hypersensitive, in vivo short-term assaying system for various environmental mutagens.

• Journal of the Microelectronics and Packaging Society
• /
• v.28 no.3
• /
• pp.25-32
• /
• 2021

In this paper, the Magneto-Electric(ME) dipole array antenna with dual-polarization in the X-Band is proposed and it is implemented and measured. The proposed array antenna is composed of 32 single ME dipole antenna and a Teflon PCB. 1 × 1 ME dipole antenna is implemented dual-polarization by radiating vertical polarization and horizontal polarization from two pairs of radiators. 2-port feeding structures are realized by lamination process using LTCC. And, each port independently feeds the radiator through a Γ-shaped feeding strip with isolation between ports. The Teflon PCB used in the antenna array has a 4-layer structure, and 2-port is fed through the top and bottom layers. The λ_g/4 transformer is applied to the transmission line of the Teflon PCB for impedance matching of the arrayed antenna and the Teflon PCB, and the optimal parameters are obtained through simulation. The measured maximum antenna gains of port 1 was 18.2 dBi, Cross-pol was 1.0 dBi. And the measured maximum antenna gains of port 1 was 18.1 dBi, Cross-pol was 3.2 dBi.

• Journal of Life Science
• /
• v.26 no.1
• /
• pp.140-145
• /
• 2016

Genes in multicellular organisms are transcribed in development, differentiation, or tissue-specific manners. The transcription of genes is activated by enhancers, which are transcription regulatory elements located at long distances from the genes. Recent studies have reported that noncoding RNAs are transcribed from active enhancers by RNA polymerase II (RNA Pol II); these are called enhancer RNAs (eRNAs). eRNAs are transcribed bi-directionally from the enhancer core, and are capped on the 5’ end but not spliced or polyadenylated on the 3’ end. The transcription of eRNAs requires the binding of transcription activators on the enhancer and associates positively with the transcription of the target gene. The transcriptional inhibition of eRNAs or the removal of eRNA transcripts results in the transcriptional repression of the coding gene. The transcriptional procedure of eRNAs causes enhancer- specific histone modifications, such as histone H3K4me1/2. eRNA transcripts directly interact with Mediator and Rad21, a cohesin subunit, generating a chromatin loop structure between the enhancer and the promoter of the target gene. The recruitment of RNA Pol II into the promoter and its elongation through the coding region are facilitated by eRNAs. Here, we will review the features of eRNAs, and discuss the mechanism of eRNA transcription and the roles of eRNAs in the transcriptional activation of target genes.

• Korean Journal of Mathematics
• /
• v.9 no.1
• /
• pp.9-20
• /
• 2001

We are concerned with an activator-inhibitor system proposed by Ohta [8]. The purpose of this paper is to study the dynamics of interfaces in an interfacial problem which is reduced from the system in order to examine how this problem is different from an activator-inhibitor system [3, 7].

• Korean Journal of Pharmacognosy
• /
• v.50 no.2
• /
• pp.102-111
• /
• 2019

Inflammation that is considered to be mainly related to pathogenesis of atopic dermatitis (AD) is the biological response of a host to stimuli, such as cellular injury or infection. In this study, we investigated the anti-inflammatory and anti-oxidative activities of white ginseng roots by ultra high pressure extraction (Gin-UHP), fermentation followed by ultra high pressure extraction (Gin-UHPF), and polyol extraction (Gin-POL). As a result, ginseng extracts were able to decrease the secretion of pro-inflammatory cytokines (interleukin-8 and tumor necrosis factor-alpha) and immunoglobulin E. Also, Gin-POL had the highest DPPH radical scavenging activity and when we compared the SOD-like activity, Gin-UHP had the highest. Moreover, we looked into the effect of these ginseng extracts on anti-aging to show the possible usefulness as a raw material of cosmetics. As a result, ginseng extracts were able to reduce the production of melanin, and inhibit the tyrosinase and elastase activities in a dose-dependent manner. The extracts also decreased the expression of MMP-1 and had a significant hyaluronidase inhibitory activity. Taken together, these results demonstrate that ginseng extracts may have an improvement effect on AD by using its anti-inflammatory and antioxidant properties.