• Journal of Microbiology and Biotechnology
• /
• v.7 no.4
• /
• pp.229-236
• /
• 1997

A gene, $phbC_{2.4.1}$ encoding poly-3-hydroxybutyric acid (PHB) synthase of Rhodobacter sphaeroides 2.4.1 was cloned by employing heterologous expression in Escherichia coli. R. sphaeroides chromosomal DNA partially digested with MboI was cloned in pUC19 followed by mobilization into E. coli harbouring $phbA,B_{AC}$ in pRK415, which code for ${\beta}$-ketothiolase and acetoacetyl CoA reductase of Alcaligenes eutrophus, respectively. Two E. coli clones carrying R. sphaeroides chromosomal fragment of $phbC_{2.4.1}$ in pUC19 were selected from ca. 10,000 colonies. The PHB-producing colonies had an opaque white appearance due to the intracellular accumulation of PHB. The structure of PHB produced by the recombinant E. coli as well as from R. sphaeroides 2.4.1 was confirmed by [$H^{+}$]-nuclear magnetic resonance (NMR) spectroscopy. Restriction analysis of the two pUC19 clones revealed that one insert DNA fragment is contained as a part of the other cloned fragment. An open reading frame of 601 amino acids of $phbC_{2.4.1}$ with approximate M.W. of 66 kDa was found from nucleotide sequence determination of the 2.8-kb SaiI-PstI restriction endonuclease fragment which had been narrowed down to support PHB synthesis through heterologous expression in the E. coli harbouring $phbA,B_{AC}$. The promoter (s) of the $phbC_{2.4.1}$ were localized within a 340-bp DNA region upstream of the $phbC_{2.4.1}$ start codon according to heterologous expression analysis.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.6
• /
• pp.560-567
• /
• 1998

We have found that Thermoactinomyces vulgaris KFB-Cl00 produces a chitinase. The optimum temperature and pH of the enzyme activity were $55^{\circ}C$ and 6.5. The enzyme was stable after heat treatment at $80^{\circ}C$ for 30 min and stable in acidic and basic conditions (PH 6.0~11.0). The thermostable endo-chitinase from Thermoactinomyces vulgaris KFB-C100 was cloned into the plasmid pBR322 by using E. coli DH5$\alpha$ as a host strain. The positive clone carrying a recombinant plasmid (PKCHI23) with a 4.1-kb fragment containing the chitinase gene was found. The recombinant plasmid was analyzed to determine the essential region for chitinase activity and obtained a 2.3-kb fragment, which was sub cloned into pTrc99A using the PstI and SalI sites to construct pTrc99A/pKCHI23-3. The resulting plasmid exerted high chitinase activity upon transformation of E. coli XL1-Blue cells. Chitinase was overproduced 14 times more in the clone cells than in the wild-type cells and the enzyme was purified to homogeneity. The purified enzyme showed the similar properties as the native chitinase from T. vulgaris in terms of molecular weight and substrate specificity. The catalytic action of the cloned enzyme was an endo type, producing chitobiose as a major reaction product.

• Journal of Electrical Engineering and Technology
• /
• v.3 no.3
• /
• pp.391-400
• /
• 2008

Multi-pulse topology of converters using elementary six-pulse GTO - VSC (gate turn off based voltage source converter) operated under fundamental frequency switching (FFS) control is widely adopted in high power rating static synchronous compensators (STATCOM). Practically, a 48-pulse ($6{\times}8$ pulse) configuration is used with the phase angle control algorithm employing proportional and integral (PI) control methodology. These kinds of controllers, for example the ${\pm}80MVAR$ compensator at Inuyama switching station, KEPCO, Japan, employs two stages of magnetics viz. intermediate transformers (as many as VSCs) and a main coupling transformer to minimize harmonics distortion in the line and to achieve a desired operational efficiency. The magnetic circuit needs altogether nine transformers of which eight are phase shifting transformers (PST) used in the intermediate stage, each rating equal to or more than one eighth of the compensator rating, and the other one is the main coupling transformer having a power rating equal to that of the compensator. In this paper, a two-level 48-pulse ${\pm}100MVAR$ STATCOM is proposed where eight, six-pulse GTO-VSC are employed and magnetics is simplified to single-stage using four transformers of which three are PSTs and the other is a normal transformer. Thus, it reduces the magnetics to half of the value needed in the commercially available compensator. By adopting the simple PI-controllers, the model is simulated in a MATLAB environment by SimPowerSystems toolbox for voltage regulation in the transmission system. The simulation results show that the THD levels in line voltage and current are well below the limiting values specified in the IEEE Std 519-1992 for harmonic control in electrical power systems. The controller performance is observed reasonably well during capacitive and inductive modes of operation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.9
• /
• pp.1226-1230
• /
• 2005

The present investigation was undertaken to study the genetic polymorphism of the DRB3 exon 2 in 75 crossbred cattle by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Five genotypes i.e. HaeIII-a, HaeIII-b, HaeIII-e, HaeIII-ab and HaeIII-ae were observed when the 284 bp PCR products were digested with HaeIII restriction enzyme. The corresponding frequencies of these patterns were 0.53, 0.04, 0.01, 0.38 and 0.04, respectively. Digestion with RsaI restriction enzyme resolved 24 different restriction patterns. The frequencies of these patterns ranged from 0.013 (RsaI-f, RsaI-k and RsaI-c/n) to 0.120 (RsaI-n). The results revealed that the crossbred cows belonged to the RsaI patterns namely b, k, l, a/l, d/s, l/n, l/o and m/n, whose corresponding frequencies were 0.027, 0.013, 0.040, 0.027, 0.040, 0.067, 0.027 and 0.067, respectively. Digestion of the 284 bp PCR product of DRB3.2 gene with PstI in the crossbred cattle did not reveal any restriction site. These results suggested the absence of the recognition site in some of the animals. These results also revealed that the crossbred cows studied were in homozygous as well as heterozygous condition. On the basis of the above results it can be concluded that the DRB3.2 gene was found to be highly polymorphic in the crossbred cattle population.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.1
• /
• pp.179-182
• /
• 2013

Human cytochrome P4502E1 (CYP2E1) is a well-conserved xenobiotic-metabolizing enzyme expressed in liver, kidney, nasal mucosa, brain, lung, and other tissues. CYP2E1 is inducible by ethanol, acetone, and other low-molecular weight substrates and may mediate development of chemically-mediated cancers. CYP2E1 polymorphisms alter the transcriptional activity of the gene. This study was conducted in order to investigate the allele frequency variation in different populations of Andhra Pradesh. Two hundred and twelve subjects belonging to six populations were studied. Genotype and allele frequency were assessed through TaqMan allelic discrimination (rs6413419) and polymerase chain reaction-sequencing (-1295G>C and -1055C>T) after DNA isolation from peripheral leukocytes. The data were compared with other available world populations. The SNP rs6413419 is monomorphic in the present study, -1295G>C and -1055C>T are less polymorphic and followed Hardy-Weinberg equilibrium in all the populations studied. The -1295G>C and -1055C>T frequencies were similar and acted as surrogates in all the populations. Analysis of HapMap populations data revealed no significant LD between these markers in all the populations. Low frequency of $CYP2E1^*c2$ could be useful in the understanding of south Indian population gene composition, alcohol metabolism, and alcoholic liver disease development. However, screening of additional populations and further association studies are necessary. The heterogeneity of Indian population as evidenced by the different distribution of $CYP2E1^*c2$ may help in understanding the population genetic and evolutionary aspects of this gene.

• International Journal of Oral Biology
• /
• v.35 no.1
• /
• pp.13-19
• /
• 2010

The DNA probes Pn17 and Pn34 were evaluated for their ability to specifically detect clinical strains of P. intermedia and P. nigrescens from a Korean population by dot blot hybridization. These probes were sequenced by extension termination and their specificity was determined by Southern blot analysis. The results revealed that the Pn17 sequence (2,517 bp) partially encodes an RNA polymerase beta subunit (rpoB) and that Pn34 (1,918 bp) partially encodes both rpoB (1-169 nts) and the RNA polymerase beta subunit (rpoB'; 695-1918 nts). These probes hybridized with both HindIII- and PstI-digested genomic DNAs from the strains of P. intermedia and P. nigrescens used in this study. Interestingly, each of the hybrid bands generated from the HindIII-digested genomic DNAs of the two bacterial species could be used to distinguish between them via restriction fragment length polymorphism. These results thus indicate that Pn17 and Pn34 can simultaneously detect P. intermedia and P. nigrescens.

• Journal of Korean Biological Nursing Science
• /
• v.7 no.1
• /
• pp.29-46
• /
• 2005

Purpose ; 본 연구는 X-염색체와 관련된 장애 중에서 가장 흔하고 심한 Duchenne Muscular Dystrophy(DMD)의 세포유전학 및 분자유전학적 특성을 설명하기 위해서 DMD에 영향을 받고 있는 두 가계의 13명을 대상으로 가계도 분석과 염색체 분석 및 DNA 분석을 하였다. Method ; DNA분석은 DNA probe을 이용한 Southern blotting method로써 RFLPs와 DMD유전자 부위의 exon소실 유무를 조사하여 아래와 같은 결과를 얻었다. Conclusion ; A 염색체 분석 : 말초혈액과 양수를 표본으로 High-Resolution GTG염색에서 A가계와 B가계의 염색체 분석에서 12명의 염색체는 정상 X-염색체였으나 B가계의 I-2(DMD여성)에서 46, x,-x,+t(2:x)(q 21.1 : p21.2)로 나타난다. B. DNA분석3 : 1) RFLPs의 분석 J66,XJ-1.1,754-11로써 B가계의 RELPs(Restriction Fragment Length Polymorphisms)에서 J66/Pst I은 1.7hb(E), 1.6kb(e)을 보여 주었고 XJ-1.1/Taq I은 3.6kb(F), 3.0kb(f), 754-11/EoR I은 4.2kb(G), 2.0kb(g)의 대립인자를 나타내었다. 이상의 결과를 바탕으로 영향을 받고 있는 남자 (II-2)의 haplotype는 보인자인 어머니의 한쪽 인자를 받았으며 어머니와 딸은 보인자이고 임산부의 태아는 남아였고 태아의 인자들은 그의 할아버지로부터 물려받아 DMD에 영향을 받지 않은 것으로 진단되었다. 2) DMD 유전자의 exon 소실에 대한 분석 cDNA probe 8과 cDNA probe 2b-3으로써 소실에 대한 진단은 영향을 받은 남자(II-2)는 cDNA probe 8에서 12, 7.3, 6.6, 4.2kb에 소실이 있고 cDNA 2b-3은 1.7kb에 소실에 나타났다.

• The Mathematical Education
• /
• v.59 no.3
• /
• pp.271-294
• /
• 2020

The purpose of this study was to explore the possibility of digital simulation by which pre-service teachers (PSTs) can approximate the core teaching practice of eliciting student thinking. This study examined PSTs' questions to elicit student thinking, their use of "pause" session and peer feedback, and their reflections on doing a digital simulation. We analyzed a two-hour digital simulation session with 13 PSTs who enrolled in the elementary mathematics methods course. The results showed that PSTs shifted their general questions to more content-specific questions throughout the simulation and made a quick transition to comparing students' strategies. The number of lead PST-initiated "pause" ranged one to four times for various reasons. Their peer-coaches did not voluntarily "pause" the simulation session but actively shared what they noticed from the student work samples and suggested the next teaching moves. Without utilizing the pause session, the dramatic improvement of questioning was not observed. Even though the PSTs felt overwhelmed with interacting with the student-avatars in real-time, they highlighted the benefits of simulations, appreciated the opportunity to learn the core teaching practice, and viewed this digital simulation as "real" and "authentic" experience. The findings of this study provide implications for re-designing a practice-based teacher education program.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.1
• /
• pp.61-68
• /
• 2004

A reproducible transformation system via optimized regeneration media for Korean rice cultivars was established using Agrobacterium tumefeciens LBA4404 (pSBM-PPGN; gusA and bar). Although japonica rice genotypes were easier to produce transgenic plants compared to Tongil type cultivars, transformation efficiencies were not always correlated with regeneration efficiencies of non-transgenic callus on the control medium. Regeneration efficiencies of Donganbyeo, Ilmibyeo, and Manchubyeo were over 50% in non-transgenic control, however, transformation efficiencies were significantly low when only sucrose was added to the media as a carbon source. However, the medium, MSRK5SS-Pr (or MSRK5SM-Pr), that contains $5\textrm{mgL}^{-1}$ kinetin, $0.5\textrm{mgL}^{-1}$ NAA, 2 % sucrose (or maltose), 3% sorbitol, and $500\textrm{mgL}^{-1}$ proline, was the most efficient not only for regeneration of non-transgenic callus but also for regeneration of transgenic callus in the presence of L-phosphinotricin (PPT). Average transformation efficiencies of 16 Korean rice cultivars were significantly enhanced by using the optimized medium from 1.5% to 5.8% in independent callus lines and from 2.9% to 19.4% in tromsgenic plants obained. Approximately 98.9% (876 out of 885) transgenic plants obtained on optimized media showed basta resistance. Stable integration, inheritance and expression of gusA and bar genes were continued by GUS assay and PCR and Southern analysis of the bar gene. With Pst1 digestion of genomic DNA of transgenic plants, one to five copies of T-DNA segment were observed; however, 76% (19 out of 25 transgenic plants) has low copy number of T-DNA. The transformants obtained from one callus line showed the same copy numbers with the same fractionized band patterns.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.4
• /
• pp.366-372
• /
• 2009

This study looked at toxicity of Mediterranean mussels, Mytilus galloprovincialis, which had accumulated paralytic shellfish toxins (PST) from early March to late May 2005 at Jinhae Bay, Korea. Alexandrium sp. was observed in low densities (< 1,000 cells/L) at the beginning of the study in March, increased rapidly in April, declined rapidly and disappeared in May. Although low densities of Alexandrium sp. were observed in March, mussel toxicity exceeded regulation level ($80{\mu}g$ STXeq. /100 g). Peak PSP (Paralytic Shellfish Poisoning) toxicity in the mussels occurred during high Alexandrium sp. cell densities in April. Mussels toxicity decreased with decline of Alexandrium sp. cell density. Major toxin components identified were $GTX_1$, $GTX_4$, followed by $C_1$, $C_2$, $GTX_2$, $GTX_3$ and neoSTX. Trace or sporadic toxin components were STX, $GTX_5$, $dcGTX_2$, $dcGTX_3$ and dcSTX. Toxin component analysis from the middle to end of the study showed that $11{\beta}$-epimers ($GTX_{3,4}$, $C_2$) were converted into $11{\alpha}$-epimers ($GTX_{1,2}$, $C_1$) and started to determine STX.