• Communications of the Korean Mathematical Society
• /
• v.12 no.3
• /
• pp.491-497
• /
• 1997

Let $C(F, M)$ and $C(S^{-1}F, S^{-1}M)$ be Cousin complexes for a modula M and a module $S^{-1}M$ over a commutative Noetherian ring with respect to a filtration F and a filtration $S^{-1}F$ respectively. In this paper, it is shown that there is an isomorphism between the Cousin complexes $S^{-1}C(F, M)$ and $C(S^{-1}F, S^{-1}M)$.

• Journal of Integrative Natural Science
• /
• v.10 no.1
• /
• pp.40-42
• /
• 2017

In this note, we study a generalization of a certain polynomial $z^n-{\sum\limits_{k=0}^{n-1}}a_kz^k$, where $\sum\limits_{k=0}^{n-1}a_k=1$, $a_k{\geq}0$ for each k, whose all zeros except for z=1 lie on the circle of radius 1/2 with center at the origin.

• Journal of Nutrition and Health
• /
• v.35 no.1
• /
• pp.53-59
• /
• 2002

Green tea has been recognized as a favorite beverage for centuries in Easter and Westers cultures. Recently, anti-tumor effects of green tea constituents have received increasing attention. However, the mechanism of catechin-mediated cytotoxicity against tumor cells remains to be elusive. To elucidate the mechanical insights of anti-tumor effects, (-)epigallocatechin-gallate(EGCG) of catechin was applied to human lung cancer A549 cells. (-)EGCG induced the death of A549 cells, which was revealed as apoptosis in DNA fragmentation assay. (-)EGCG induced the activation of caspase family cysteine proteases including capase-3, -8 and -9 proteases in A549 cells. Furthermore, (-)EGCG increased the phosphotransferase activity of c-Jun N-terminal kinase 1JNK 1), which further induced tole transcriptional activation of activating protein-1(AP-1) in A549 cells. We suggest that (-)EGCG-induced apotosis of A549 cells is mediated by signaling pathway involving caspase family cysteine protease, JNK1 and transcription factor, AP-1.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1996.07a
• /
• pp.40-47
• /
• 1996

The promoters of a variety of plant genes are characterized by the presence of TGACG motif-containing sequences. These genes often exhibit quite diverse expression characteristics and in many case the TGACG-motif has been demonstrated to be essential for expression. Here we report the isolation and characterization of a soybean cDNA that encodes a novel basic/leucine zipper (bZIP) protein, STF1, that specifically interacts with Hex (TGACGTGG) and CRE (TGACGTCA) sequences. This protein contains a bZIP motif at C-teminus and an acidic domain at N-terminus. DNA binding specificities, heterodimer formation, and expression characteristics of STF1 were compared with a soybean TGA1 protein, STGA1. The soybean STF1 interacts with TGACG-sequences containing an ACGT core, while STGA1 requires TGACG as a sufficient binding sequence. The flanking sequences to the TGACG motif affected DNA binding of STF1 siginificantly. The STF1 mRNA is found mainly in dark grown soybean seedling with higher expression in apical and elongating hypocotyl, while STGA1 mRNA is highly abundant in roots of light grown plants. Furthermore, we demonstrate that STF1 heterodimerzes with G-box binding factorss (GBFs) which was not observed with TGA1. The fact that STF1 possesses both distinct DNA binding speficities and heterodimerization properties suggest that STF1 belongs to a new family of plant bZIP proteins which recognize the Hex/CRE motif.

• The Plant Pathology Journal
• /
• v.27 no.1
• /
• pp.20-25
• /
• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.1 no.1
• /
• pp.29-33
• /
• 2000

We cloned and characterized a very late expression factor 1 gene, vlf-1, which regulates the level of very late gene transcripts, from Bombyx mori nuclear polyhedrosis virus (BmNPV) K1 strain. The 1,140 bp vlf-1 has an open reading frame of 379 amino acid and a MW of 44 kDa. The vlf-1 nucleotide sequence of BmNPV-Kl showed high homology with Autographa californica nuclear polyhedrosis virus and BmNPV T3 strain so far known, and its deduced amino acid residues were identical to those of BmNPV T3. The location of vlf-1 in the BmNPV-Kl genome was confirmed by Southern blot analysis and its expression patterns at the transcriptional level were confirmed by Northern hybridization analysis.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.7
• /
• pp.2135-2138
• /
• 2014

A kinetic study is reported for the SNAr reaction of 1-Y-substituted-phenoxy-2,4-dinitrobenzenes (1a-1h) with OH- in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The second-order rate constant ($k_{OH^-}$) increases as the substituent Y in the leaving group changes from an electron-donating group (EDG) to an electronwithdrawing group (EWG). The Br${\o}$nsted-type plot for the reactions of 1a-1h is linear with ${\beta}_{lg}$ = -0.16, indicating that the reactivity of substrates 1a-1h is little affected by the leaving-group basicity. A linear Br${\o}$nsted-type plot with ${\beta}_{lg}=-0.3{\pm}0.1$ is typical for reactions reported previously to proceed through a stepwise mechanism in which formation of a Meisenheimer complex is the rate-determining step (RDS). The Hammett plot correlated with ${\sigma}_Y{^{\circ}}$ constants results in a much better correlation than that correlated with ${\sigma}_Y{^-}$constants, implyng that no negative charge is developing on the O atom of the leaving group (or expulsion of the leaving group is not advanced at all in the TS). This excludes a possibility that the $S_NAr$ reaction of 1a-1h with $OH^-$ proceeds through a concerted mechanism or via a stepwise pathway with expulsion of the leaving group being the RDS. Thus, the current reactions have been concluded to proceed through a stepwise mechanism in which expulsion of the leaving group occurs rapidly after the RDS.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.7
• /
• pp.911-917
• /
• 2022

As valuable antibiotics, microbial natural products have been in use for decades in various fields. Among them are polyene compounds including nystatin, amphotericin, and nystatin-like Pseudonocardia polyenes (NPPs). Polyene macrolides are known to possess various biological effects, such as antifungal and antiviral activities. NPP A1, which is produced by Pseudonocardia autotrophica, contains a unique disaccharide moiety in the tetraene macrolide backbone. NPP B1, with a heptane structure and improved antifungal activity, was then developed via genetic manipulation of the NPP A1 biosynthetic gene cluster (BGC). Here, we generated a Streptomyces artificial chromosomal DNA library to isolate a large-sized NPP B1 BGC. The NPP B1 BGC was successfully isolated from P. autotrophica chromosome through the construction and screening of a bacterial artificial chromosome (BAC) library, even though the isolated 140-kb BAC clone (named pNPPB1s) lacked approximately 8 kb of the right-end portion of the NPP B1 BGC. The additional introduction of the pNPPB1s as well as co-expression of the 32-kb portion including the missing 8 kb led to a 7.3-fold increase in the production level of NPP B1 in P. autotrophica. The qRT-PCR confirmed that the transcription level of NPP B1 BGC was significantly increased in the P. autotrophica strain containing two copies of the NPP B1 BGCs. Interestingly, the NPP B1 exhibited a previously unidentified SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibition activity in vitro. These results suggest that the Streptomyces BAC cloning of a large-sized, natural product BGC is a valuable approach for titer improvement and biological activity screening of natural products in actinomycetes.

• Journal of the Korean Mathematical Society
• /
• v.54 no.3
• /
• pp.967-986
• /
• 2017

We give the necessary condition for an operator defined on a cartesian product of $c_0(\mathcal{X})$ spaces to be summing or dominated and we show that for the multiplication operators this condition is also sufficient. By using these results, we show that ${\Pi}_s(c_0,{\ldots},c_0;c_0)$ contains a copy of $l_s(l^m_2{\mid}m{\in}\mathbb{N})$ for s > 2 or a copy of $1_s(l^m_1{\mid}{\in}\mathbb{N})$, for any $l{\leq}S$ < ${\infty}$. Also ${\Delta}_{s_1,{\ldots},s_n}(c_0,{\ldots},c_0;c_0)$ contains a copy of $l_{{\upsilon}_n(s_1,{\ldots},s_n)}$ if ${\upsilon}_n(s_1,{\ldots},s_n){\leq}2$ or a copy of $l_{{\upsilon}_n(s_1,{\ldots},s_n)}(l^m_2{\mid}m{\in}\mathbb{N})$ if 2 < ${\upsilon}_n(s_1,{\ldots},s_n)$, where ${\frac{1}{{\upsilon}_n(s_1,{\ldots},s_n})}={\frac{1}{s_1}}+{\cdots}+{\frac{1}{s_n}}$. We find also the necessary and sufficient conditions for bilinear operators induced by some method of summability to be 1-summing or 2-dominated.

• BMB Reports
• /
• v.30 no.5
• /
• pp.342-345
• /
• 1997

Catechol 1,2-dioxygenase $I_1$ (CD $I_1$) gene of Acinetobacter Iwoffii K24, $catA_1$ was expressed in Escherichia coli and was partially purified by using a MonoQ column. Expressed CD $I_1$ had the same molecular weight as purified CD $I_1$ from A. Iwoffii K24 on SDS-PAGE. Expressed CD $I_1$ was also identified by Western blotting and peptide sequencing of N-terminal and internal regions. When compared with purified CD $I_1$ of A. Iwoffii K24, expressed CD $I_1$ had similar substrate specificities and the effects of compounds on enzyme activity. N-terminal amino acid sequence of CD I expressed in E. coli was the same as that of purified CD $I_1$, suggesting that CD $I_1$ may be under the same posttranslational processing in E. coli and A. Iwoffii K24.