• Journal of fish pathology
• /
• v.6 no.2
• /
• pp.93-101
• /
• 1993

The RNAI mutation of Saccharomyces cerevisia is a recessive and temperature sensitive lethal mutation which interferes with the production of mRNA, rRNA, and tRNA. However, the precise role of RNAI gene have not been revealed until yet. We have cloned rna1-1 mutant gene from rna1-1 mutant yeast strain(R49 ; trpl, ura3-52, rna1-1). The 3.4kb BglII fragment of wild type RNAI clone(81-2-6) contains whole RNAI gene. The genomic southern blotting with BglII digested R49 genomic DNA as a probe shows the unique and identical band with wild type 3.4kb BglII fragment. Therefore, We prepared partial BglII genomic library(3~4kb BglII fragments) into BamH I site of pUC19. The rna 1-1 mutant clone was screened with Digoxigenin(DIG)-lableled probe by high density colony hybridization. The 5'-flanking region of rna1-1 gene was sequenced by dideoxy chain termination method. The 5'-flanking sequence of RNAI gene contains three TATA-like sequence ; TAATA, TATA and TTTTAA at position of -67, -45, and -36 from first ATG codon respectively. The 5'-flanking region of wild type RNA I gene from ATG codon to -103nt was deleted with Bal31 exonuclease digestion, generating $pUC{\Delta}$/RNA I. After constructing $pYEP{\Delta}RNA$ I (consists of -103nt deleting RNA I gene, URA3 gene, $2{\mu}m$ rep. origin), pYEPrna1-1(consists of Xba I fragment of pUCrna1-1. URA3 gene, $2{\mu}m$ rep. origin), and pYEPRNAI. each plasmid was transformed into host strain(trpl, ura3-52, rna1-1) by electroporation, respectively. Yeast transformant carrying $pYEP{\Delta}RNA$ I did not complement the thermal sensitivity of rna1-1 gene. It means that TATA-like sequences in 5'-flanking region is not TATA sequence for transcribing RNAI gene and there may be other essential sequence in upstream region for the transcription of RNAI gene.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.72.1-72.1
• /
• 2013

Even though current microlensing follow-up observations focus on high-magnification events due to the high efficiency of planet detection, it is very difficult to do a confident detection of planets in high-magnification events with extremely weak central perturbations (i.e., the fractional deviation is ${\delta}{\leq}0.02$). For the confident detection of planets in the extremely weak central perturbation events, it is needed both the high cadence monitoring and the high photometric accuracy. A next-generation ground-based observation project, KMTNet (Korea Microlensing Telescope Network), satisfies both the conditions. Here we investigate how well planets in high-magnification events with extremely weak central perturbations are detected by KMTNet. First, we determine the probability of occurrence of events with ${\delta}{\leq}0.02$. From this, we find that for ${\leq}100M_E$ planets in the separation of $0.2AU{\leq}d{\leq}20AU$, events with ${\delta}{\leq}0.02$ occur with a frequency of more than 70%, in which d is the projected planet-star separation. Second, we estimate the efficiency of detecting planetary signals in the events with ${\delta}{\leq}0.02$ via KMTNet. We find that for main-sequence and subgiant source stars, ${\geq}1M_E$ planets can be detected more than 50% in a certain range that has the efficiency of ${\geq}10%$ and changes with the planet mass.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.18 no.1
• /
• pp.16-24
• /
• 1981

The delay-lock loop (DLL) is a statistically optimum device for tracking the de]ay difference between two correlated waveforms. In this paper an extended n - $\Delta$ (n=1,2,3‥‥) DLL is described, and its baseband performance including the frequency to lose lock is analyzed. The present DLL system employs a correlator and a pseudonoise sequence synthesizer that has been improved from the previously used ones The shape of the correlator characterigtic has the form of expanded S-curve. Despite of increase noise, this extended DLL has desirable characteristics in tracking range and initial synchronization time. Comparing a 3 - $\Delta$ DLL with a 1 - A DLL, the former Bives three times faster initial synchronization time with the serial synchronization method, and gives two times immunity against doppler shift.

• Journal of the Korean Chemical Society
• /
• v.19 no.1
• /
• pp.11-15
• /
• 1975

Kinetic study of halogen exchange for N,N-dimethylcarbamoyl chloride and N,N-diethylcarbamoyl chloride in acetone by using radioisotopic halide ions has been carried out at two temperatures as a part of studying the reactivity of carbonyl carbon atom. The order of nucleophilicity showed a similar tendency as that for alkyl chloroformate, but reaction rate is much slower than that for solvolysis and alkyl chloroformate. The activation parameters,${\Delta}H^*$and${\Delta}S^*$ were found to decrease in sequence $Cl^{\rightarrow}Br^{\rightarrow}I^-$ for N,N-dialkylcarbamoyl chlorides. The results are interpreted in terms of solvation effect, degree of bond-breaking and bond-formation and electronic requirements.

• Journal of the Korean Chemical Society
• /
• v.17 no.6
• /
• pp.406-410
• /
• 1973

Kinetic study of halide exchange for dimethylsulfamoyl chloride in dry acetone by using radioisotopic halide ions has been carried out at two temperatures. The result of the order of nucleophilicity, as compared with benzenesulfonyl chloride, shows a similar tendency but reaction rate is slower, more than $10^{-2}$times, than benzenesulfonyl chloride. The activation parameter, ${\Delta}H^{\neq}\;and\;{\Delta}S^{\neq}$ decrease in sequence $Cl^-\;>\;Br^-\;>\;I^-$ in dimethylsulfamoyl chloride but it is the reverse order found for benzenesulfonyl chloride. The results are interpreted with bond-breaking, bond-formation, and electronic requirments, and in the light of HSAB Principle.

• Kyungpook Mathematical Journal
• /
• v.60 no.4
• /
• pp.683-710
• /
• 2020

Let ℕ be the set of nonnegative integers and 𝕬 be a 2-torsion free triangular algebra over a commutative ring ℛ. In the present paper, under some lenient assumptions on 𝕬, it is proved that if Δ = {𝛿_n}_n∈ℕ is a sequence of ℛ-linear mappings 𝛿_n : 𝕬 → 𝕬 satisfying ${\delta}_n([[x,\;y],\;z])\;=\;\displaystyle\sum_{i+j+k=n}\;[[{\delta}_i(x),\;{\delta}_j(y)],\;{\delta}_k(z)]$ for all x, y, z ∈ 𝕬 with xy = 0 (resp. xy = p, where p is a nontrivial idempotent of 𝕬), then for each n ∈ ℕ, 𝛿_n = d_n + 𝜏_n; where d_n : 𝕬 → 𝕬 is ℛ-linear mapping satisfying $d_n(xy)\;=\;\displaystyle\sum_{i+j=n}\;d_i(x)d_j(y)$ for all x, y ∈ 𝕬, i.e. 𝒟 = {d_n}_n∈ℕ is a higher derivation on 𝕬 and 𝜏_n : 𝕬 → Z(𝕬) (where Z(𝕬) is the center of 𝕬) is an ℛ-linear map vanishing at every second commutator [[x, y], z] with xy = 0 (resp. xy = p).

• Journal of Microbiology and Biotechnology
• /
• v.10 no.5
• /
• pp.670-676
• /
• 2000

Several clones obtained from Serratia marcescens stimulated E. coli TP2139 (${\Delta}lac, \;{\Delta} crp$) cells to use maltose as a carbon source. The crp gene clone, pCKB12, was confirmed to stimulate the $\beta$-galactosidase activity, by Southern hybridization [31]. The nucleotide sequence of the crp region consisting of 1,979 bp was determined. The sequencing of the fragment led to the identification of two open reading frames: One of these, the crp gene, encoded 210 amino acid and the other encoded a truncated protein. The S. marcescens and E. coli crp genes showed a higher degree of divergence in their nucleotide sequence with 120 changes, however, the corresponding amino acid sequences showed only two amino acid differences. Yet, an analysis of the amino acid divergence revealed that the catabolite gene activator protein, the crp gene product, was the most conserved protein observed so far. Using a crp-lac protein fusion, it was demonstrated that S. marcescens CRP could repress its own expression, probably via a mechanism similar to that previously described for the E. coli crp gene.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.10
• /
• pp.1688-1694
• /
• 2007

A gene encoding the mannanase of Bacillus subtilis WL-3, which had been isolated from Korean soybean paste, was cloned into Escherichia coli and the nucleotide sequence of a 2.7-kb DNA fragment containing the mannanase gene was subsequently determined. The mannanase gene, designated manA, consisted of 1,080 nucleotides encoding a polypeptide of 360 amino acid residues. The deduced amino acid sequence was highly homologous to those of mannanases belonging to glycosyl hydrolase family 26. The manA gene was strongly expressed in B. subtilis 168 by cloning the gene downstream of a strong B. subtilis promoter of plasmid $pJ27{\Delta}88U$. In flask cultures, the production of mannanase by recombinant B. subtilis 168 reached maximum levels of 300 units/ml and 450 units/ml in LB medium and LB medium containing 0.3% locust bean gum, respectively. Based on the zymogram ofthe mannanase, it was found that the mannanase produced by recombinant B. subtilis could be maintained stably without proteolytic degradation during the culture time.

• Proceeding of EDISON Challenge
• /
• 2016.03a
• /
• pp.313-318
• /
• 2016

2차원 화합물 반도체인 Metal monochalcogenides (MMC)는 원자 4층으로 이루어진 tetralayer (TL)가 층상으로 쌓여진 구조이다. 서로 이웃한 tetralayer들이 쌓이는 방법에 따라 4가지의 stacking sequence를(${\beta}$, ${\varepsilon}$, ${\gamma}$, ${\delta}$) 고려할 수 있으며 물질에 따라 상대적인 안정성이 달라진다. GaS는 ${\beta}-type$이 가장 안정하다고 알려져 있다. 이 연구에서는 GaS의 층수를 4층까지 쌓으며, ${\beta}$와 ${\varepsilon}$의 stacking sequence의 모든 경우를 다루어 van der Waals interaction을 고려한 LCAO-DFT 제일원리 계산을 수행하였다. 그 결과를 원자구조의 변화, 에너지 안정성, 전자구조의 변화로 나누어 분석하였다. TL 층이 많을수록 TL의 thickness가 감소하고 더 높은 에너지 안정성을 나타냈다. 또한 stacking sequence를 고려하였을 때 ${\varepsilon}$ stacking을 한 결과가 더 안정한 에너지가 나왔다. 이후 ${\varepsilon}$ stacking을 하였을때의 전자구조 변화를 energy band와 projected density of states를 이용해 관찰하였다.

• Molecules and Cells
• /
• v.22 no.2
• /
• pp.146-153
• /
• 2006

Cell polarity is critical for the division, differentiation, migration, and signaling of eukaryotic cells. RAX2 of budding yeast encodes a membrane protein localized at the cell cortex that helps maintain the polarity of the bipolar pattern. Here, we designate SPAC6f6.06c as $rax2^+$ of Schizosaccharomyces pombe, based on its sequence homology with RAX2, and examine its function in cell polarity. S. pombe $rax2^+$ is not essential, but ${\Delta}rax2$ cells are slightly smaller and grow slower than wild type cells. During vegetative growth or arrest at G1 by mutation of cdc10, deletion of $rax2^+$ increases the number of cells failing old end growth just after division. In addition, this failure of old end growth is dramatically increased in ${\Delta}tea1{\Delta}rax2$, pointing to genetic interaction of $rax2^+$ with $tea1^+$. ${\Delta}rax2$ cells contain normal actin and microtubule cytoskeletons, but lack actin cables, and the polarity factor for3p is not properly localized at the growing tip. In ${\Delta}rax2$ cells, and endogenous rax2p is localized at the cell cortex of growing cell tips in an actin- and microtubule-dependent manner. However, ${\Delta}rax2$ cells show no defects in cell polarity during shmoo formation and conjugation. Taken together, these observations suggest that rax2p controls the cell polarity of fission yeast during vegetative growth by regulating for3p localization.