• Journal of Microbiology
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• 제44권6호
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• pp.649-654
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• 2006

A standard type II polyketide synthase (PKS) gene cluster was isolated while attempting to clone the biosynthetic gene for lipstatin from Streptomyces toxytricini NRRL 15,443. This result was observed using a Southern blot of a PstI-digested S. toxytricini chromosomal DNA library with a 444 bp amplified probe of a ketosynthase (KS) gene fragment. Four open reading frames [thioesterase (TE), $\beta$-ketoacyl systhase (KAS), chain length factor (CLF), and acyl carrier protein (ACP)], were identified through the nucleotide sequence determination and analysis of a 4.5 kb cloned DNA fragment. In order to confirm the involvement of a cloned gene in lipstatin biosynthesis, a gene disruption experiment for the KS gene was performed. However, the resulting gene disruptant did not show any significant difference in lipstatin production when compared to wild-type S. toxytricini. This result suggests that lipstatin may not be synthesized by a type II PKS.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.767-771
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• 2008

Second-order rate constants have been measured spectrophotometrically for the Michael-type reaction of 1-(Xsubstituted phenyl)-2-propyn-1-ones (2a-f) with amines in $H_2O$ at 25.0 ${\pm}$ 0.1 ${^{\circ}C}$. A linear Brønsted-type plot is obtained with ${\beta}_{nuc}$ = 0.25 ${\pm}$ 0.02, a typical $\beta_{nuc}$ value for reactions which proceed through a stepwise mechanism with attack of amine on the electrophilic center being the rate-determining step. Secondary alicyclic amines are found to be more reactive than isobasic primary amines. The Hammett plot for the reactions of 2a-f with morpholine is not linear, i.e., the substrate with a strong electron-donating group (e.g., 4-MeO) exhibits a negative deviation from the Hammett plot. However, the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation with ρ = 0.62 and r = 0.82. Thus, it has been proposed that the nonlinear Hammett plot is not due to a change in the ra te-determining step but due to ground-state stabilization through resonance interactions.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5671-5675
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• 2012

Objective: Arrestins act as mediators of G protein-coupled receptor (GPCR) desensitization and trafficking, also actin as a scaffold for many intracellular signaling network. The role that ${\beta}$-arrestin 1 plays in gastric cardiac adenocarcinoma (GCA) and its clinicopathologic significance are untouched. Methods: Fifty patients with gastric cardiac adenocarcinoma were retrospectively enrolled and ${\beta}$-arrestin 1 was detected using immunohistochemistry in tissue samples. Results: Nuclear expression of ${\beta}$-arrestin 1 was observed in 78% of GCA samples (39/50) and cytoplasmic expression in 70% (35/50). ${\beta}$-arrestin 1 could be found in both nucleus and cytoplasm of 54% GCA (27/50) or in either of them in 94% (47/50). ${\beta}$-arrestin 1 protein positivity in well/moderately differentiated carcinomas was significantly higher than that in poorly differentiated carcinomas (P=0.005). We found increased expression of ${\beta}$-arrestin 1 in cytoplasm was correlated with lymph nodal metastasis (P=0.002) and pathological lymph nodal staging (P=0.030). We also found ${\beta}$-arrestin 1 to be over-expressed in glandular epithelia cells of mucinous adenocarcinoma, a tumour type associated with an adverse outcome of gastric cardiac adenocarcinoma (P=0.022). Conclusion: ${\beta}$-arrestin 1 is over-expressed in the nucleus and/or cytoplasm of gastric cardiac adenocarcinoma. However, ${\beta}$-arrestin 1 has no relationship with the prognosis of gastric cardiac adenocarcinoma (P>0.05). Our data imply that ${\beta}$-arrestin 1 in cytoplasm may be involved in differentiation and metastasis of gastric cardiac adenocarcinoma.

• Molecules and Cells
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• 제27권6호
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• pp.651-656
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• 2009

The formation of ${\beta}$-amyloid peptide ($A{\beta}$) is initiated from cleavage of amyloid precursor protein (APP) by a family of protease, ${\alpha}$-, ${\beta}$-, and ${\gamma}$-secretase. Sub W, a substrate peptide, consists of 10 amino acids, which are adjacent to the ${\beta}$-cleavage site of wild-type APP, and Sub M is Swedish mutant with double mutations on the left side of the ${\beta}$-cleavage site of APP. Sub W is a normal product of the metabolism of APP in the secretary pathway. Sub M is known to increase the efficiency of ${\beta}$-secretase activity, resulting in a more specific binding model compared to Sub W. Three-dimensional structures of Sub W and Sub M were studied by CD and NMR spectroscopy in water solution. On the basis of these structures, interaction models of ${\beta}$-secretase and substrate peptides were determined by molecular dynamics simulation. Four hydrogen bonds and one water-mediated interaction were formed in the docking models. In particular, the hydrogen bonding network of Sub M-BACE formed spread over the broad region of the active site of ${\beta}$-secretase (P5-P3'), and the side chain of P2- Asn formed a hydrogen bond specifically with the side chain of Arg235. These are more favorable to the cleavage of Sub M by ${\beta}$-secretase than Sub W. The two substrate peptides showed different tendency to bind to ${\beta}$-secretase and this information may useful for drug development to treat and prevent Alzheimer's disease.

• Radiation Oncology Journal
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• 제31권2호
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• pp.57-65
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• 2013

Beta-lapachone (${\beta}$-Lap; 3,4-dihydro-2, 2-dimethyl-2H-naphthol[1, 2-b]pyran-5,6-dione) is a novel anti-cancer drug under phase I/II clinical trials. ${\beta}$-Lap has been demonstrated to cause apoptotic and necrotic death in a variety of human cancer cells in vitro and in vivo. The mechanisms underlying the ${\beta}$-Lap toxicity against cancer cells has been controversial. The most recent view is that ${\beta}$-Lap, which is a quinone compound, undergoes two-electron reduction to hydroquinone form utilizing NAD(P)H or NADH as electron source. This two-electron reduction of ${\beta}$-Lap is mediated by NAD(P)H:quinone oxidoreductase (NQO1), which is known to mediate the reduction of many quinone compounds. The hydroquinone forms of ${\beta}$-Lap then spontaneously oxidizes back to the original oxidized ${\beta}$-Lap, creating futile cycling between the oxidized and reduced forms of ${\beta}$-Lap. It is proposed that the futile recycling between oxidized and reduced forms of ${\beta}$-Lap leads to two distinct cell death pathways. First one is that the two-electron reduced ${\beta}$-Lap is converted first to one-electron reduced ${\beta}$-Lap, i.e., semiquinone ${\beta}$-Lap $(SQ)^{{\cdot}-}$ causing production of reactive oxygen species (ROS), which then causes apoptotic cell death. The second mechanism is that severe depletion of NAD(P)H and NADH as a result of futile cycling between the quinone and hydroquinone forms of ${\beta}$-Lap causes severe disturbance in cellular metabolism leading to apoptosis and necrosis. The relative importance of the aforementioned two mechanisms, i.e., generation of ROS or depletion of NAD(P)H/NADH, may vary depending on cell type and environment. Importantly, the NQO1 level in cancer cells has been found to be higher than that in normal cells indicating that ${\beta}$-Lap may be preferentially toxic to cancer cells relative to non-cancer cells. The cellular level of NQO1 has been found to be significantly increased by divergent physical and chemical stresses including ionizing radiation. Recent reports clearly demonstrated that ${\beta}$-Lap and ionizing radiation kill cancer cells in a synergistic manner. Indications are that irradiation of cancer cells causes long-lasting elevation of NQO1, thereby sensitizing the cells to ${\beta}$-Lap. In addition, ${\beta}$-Lap has been shown to inhibit the repair of sublethal radiation damage. Treating experimental tumors growing in the legs of mice with irradiation and intraperitoneal injection of ${\beta}$-Lap suppressed the growth of the tumors in a manner more than additive. Collectively, ${\beta}$-Lap is a potentially useful anti-cancer drug, particularly in combination with radiotherapy.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.96-97
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• 2000

• East Asian mathematical journal
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• 제1권
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• pp.35-42
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• 1985

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.271.2-271
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• 2002

• 한국수산과학회지
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• 제33권3호
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• pp.257-261
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• 2000

두토막눈썹참갯지렁이의 피부계는 바깥쪽으로 부터 큐티클층, 상피층, 진피층으로 구성된다. 큐티클층은 외분비공을 가지며, 표면은 epicuticular projections로 덮여있다. 큐티클층과 상피층의 지지세포 사이에서는 반접착반이 관찰된다. 상피층에서는 지지세포와 선세포들이 관찰된다. 지지세포는 불규칙한 형태이며, 이들 세포의 핵은 뚜렷하고 크며, $1{\~}2$개의 인을 가진다. 세포질에서는 잘 발달된 당김세사와 다수의 미토콘드리아, 조면소포체, 유리리보좀 그리고 전자밀도가 아주 높은 소수의 색소과립들이 관찰된다. 선세포는 AB-PAS에 청색으로 반응하였으며, 투과전자현미경 관찰 결과 ${\alpha}, {\beta}, {\gamma}$의 세 종류로 구분할 수 있다. 첫 번째 종류인 ${\alpha} type$은 난형으로 뚜렷한 핵을 가지며, 세포질에서는 잘 발달된 당김세사와 막으로 싸인 직경 $0.8{\~}~l.5 {\mu}m$크기의 분비과립들이 세포질 한쪽에 밀집되어 있는 것을 관찰할 수 있다. 두 번째 종류인 ${\beta} type$은 세포의 형태가 불규칙하며, 커다란 공포를 가지며, 직경 $0.5{\~}~0.8 {\mu}m$크기의 분비과립들이 세포질 전체에 분포한다. 세 번째 종류인 ${\gamma} type$은 세포의 형태가 불규칙하며, 잘 발달된 소포체와 골지체 그리고 직경 $0.2{\~}~0.3 {\mu}m$ 크기의 분비과립을 가지며, 이들의 전자밀도는 선세포들의 분비과립 가운데 가장 높다.

• 기본간호학회지
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• 제19권2호
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• pp.190-200
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• 2012

Purpose: The purpose of this study was to provide basic data for the development of weight control programs to maintain and promote healthy behavior in women college students by identifying their weight control behaviors and factors that influence these behaviors. Method: Data were collected from 300 women student participants and were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and multiple regression with the SPSS 18.0 program. Result: Weight control behavior showed a significant difference according to participants' gender role identity type. Weight control behaviors were correlated with self-efficacy, body image, objective BMI, and ideal BMI. Factors influencing weight control behavior were self-efficacy (${\beta}$= .449, $p$<.001), secret method for weight loss (${\beta}$= .181, $p$<.001), monthly allowance below 200,000 won (${\beta}$= .156, $p$= .006), weight control support from others (${\beta}$= .124, $p$= .013), eating breakfast (${\beta}$= .119, $p$= .015), and age (${\beta}$= .113, $p$= .023) with R-sq. value of 45.3%. Conclusion: The results of the study indicate that development of interventions for weight control behavior and health education for college women should reflect identified factors influencing weight control behavior and gender role identity.