• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.669-672
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• 2001

Pseudo-first-order rate constants have been measured spectrophotometrically for the title reactions. The plot of kobs vs the concentration of alkali metal ethoxides is linear for the reactions performed in the presence of complexing age nt, 18-crown-6 ether, but curved upwardly for the corresponding reactions performed in the absence of the complexing agent, indicating that the alkali metal ions studied in this study behave as a catalyst. The catalytic effect was found to increase in the order Li+ << K+ ${\leq}$ Na+. Second-order rate constants were determined for the reactions with dissociated free ethoxide (kEtO-) and with ion paired alkali metal ethoxides (kEtO-M+ ) from ion pairing treatments. The magnitude of catalytic effect (kEtO-M+/kEtO-) was found to be 2.3, 9.5 and 8.7 for the reaction of 8-(5-nitroquinolyl) 2-furoate, while 1.4, 3.6 and 4.2 for that of 4-nitrophenyl 2-furoate, indicating that the catalytic effect is larger in the reaction of the former substrate than in that of the latter one. The larger catalytic effect was attributed to two possible complexing sites with alkali metal ions in the former substrate.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.673-677
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• 2001

Pseudo-first-order rate constants have been measured spectrophotometrically for the reactions of 8-(5-nitroquinolyl) 3-furoate with alkali metal ethoxides in anhydrous ethanol. The plot of kobs vs the concentration of alkali metal ethox ides is linear for the reactions performed in the presence of a complexing agent, 18-crown-6 ether, but exhibits upward curvatures for the corresponding reactions performed in the absence of the complexing agent, indicating that the alkali metal ions in this study behave as catalysts. Second-order rate constants were determined for the reactions with dissociated free ethoxide (kEtO-) and with ion paired alkali metal ethoxides (kEtO-M + ) from ion pairing treatments. The magnitude of catalytic effect (kEtO-M + /kEtO-) was found to be 1.7, 3.4 and 2.5 for the reaction of 8-(5-nitroquinolyl) 3-furoate, while 1.4, 3.6 and 4.2 for that of 4-nitrophenyl 2-furoate, 1.8, 3.7 and 2.4 for that of 8-(5-nitroquinolyl) benzoate, and 2.0, 9.8 and 9.3 for that of 8-(5-nitroquinolyl) 2-furoate with EtO- Li+ , EtO- Na+ and EtO- K+ , respectively. A 5-membered chelation at the leaving group is suggested to be responsible for the catalytic effect shown by alkali metal ions.

• 생명과학회지
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• 제20권1호
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• pp.97-102
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• 2010

식품단백질의 물성과 기능성을 개선시켜 산업적인 가치가 매우 높은 TGase를 생산하는 S. platensis YK-2의 분자 유전학적인 연구를 위해 형질전환방법을 확립하였으며 본 연구를 위해 도입된 방법은 대장균을 plasmid DNA의 공여체로, S. platensis의 포자를 수용체로 사용하는 접합전달법이다. S. platensis를 위한 최적 접합전달조건은 50 mM의 $MgCl_2$를 첨가한 MS배지에 열처리를 하지 않은 포자와 $5{\times}10^7$의 plasmid DNA 공여체인 E. coli를 사용하는 것이다. 또 본 연구를 통해 얻어진 접합전달체의 attB site에 대한 분석을 통해 S. platensis chromosome의 pirin 상동체를 코드하는 ORF내에 attB site가 단일위치로 존재하고 있으며 이미 밝혀진 다른 방선균유래 attB site의 염기서열에 대해 77.8%~96.3%의 상동성을 나타냈다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1075-1083
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• 2015

Adipose tissue deposited within muscle fibers, known as intramuscular fat (IMF or marbling), is a major determinant of meat quality and thereby affects its economic value. The biological mechanisms that determine IMF content are therefore of interest. In this study, 48 genes involved in the bovine peroxisome proliferator-activated receptor signaling pathway, which is involved in lipid metabolism, were investigated to identify candidate genes associated with IMF in the longissimus dorsi of Hanwoo (Korean cattle). Ten genes, retinoid X receptor alpha, peroxisome proliferator-activated receptor gamma (PPARG), phospholipid transfer protein, stearoyl-CoA desaturase, nuclear receptor subfamily 1 group H member 3, fatty acid binding protein 3 (FABP3), carnitine palmitoyltransferase II, acyl-Coenzyme A dehydrogenase long chain (ACADL), acyl-Coenzyme A oxidase 2 branched chain, and fatty acid binding protein 4, showed significant effects with regard to IMF and were differentially expressed between the low- and high-marbled groups (p<0.05). Analysis of the gene co-expression network based on Pearson's correlation coefficients identified 10 up-regulated genes in the high-marbled group that formed a major cluster. Among these genes, the PPARG-FABP4 gene pair exhibited the strongest correlation in the network. Glycerol kinase was found to play a role in mediating activation of the differentially expressed genes. We categorized the 10 significantly differentially expressed genes into the corresponding downstream pathways and investigated the direct interactive relationships among these genes. We suggest that fatty acid oxidation is the major downstream pathway affecting IMF content. The PPARG/RXRA complex triggers activation of target genes involved in fatty acid oxidation resulting in increased triglyceride formation by ATP production. Our findings highlight candidate genes associated with the IMF content of the loin muscle of Korean cattle and provide insight into the biological mechanisms that determine adipose deposition within muscle.

• 대한유전성대사질환학회지
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• 제5권1호
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• pp.1-8
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• 2005

제II형 글루타르산혈증은 발생 시기와 정도에 따라서 질병의 경과를 달리한다. 지발형의 경우 평상시에는 증상이 없고, 검사 소견도 정상 소견을 보이나 대사가 증가되는 hypercatabolic status에서는 저혈당, 대사성 산혈증, 고암모니아혈증 등이 나타나며, 다양한 신경학적인 증상들이 나타날 수 있다. 따라서 신경학적인 증상들이 있는 경우 기본적인 검사들을 시행해 보고, 위와 같은 소견들이 보이는 경우에는 소변의 유기산 분석을 통한 진단이 필요하다. 정맥내로 포도당이 투여되면 유기산 분석의 양상이 매우 빠른 속도로 정상화될 수 있으므로 정맥내로 포도당을 투여하기 전에 소변 검체를 채취하여 냉동 보관하는 것은 정확하고 빠른 진단을 위하여 필수적이라고 할 수 있다.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.579-588
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• 2015

Fungi of the genus Pestalotiopsis have drawn attention for their capability to produce an array of bioactive secondary metabolites that have potential for drug development. Here, we report the determination of a polyketide derivative compound, pestalotiollide B, in the culture of the saprophytic fungus Pestalotiopsis microspora NK17. Structural information acquired by analyses with a set of spectroscopic and chromatographic techniques suggests that pestalotiollide B has the same skeleton as the penicillide derivatives, dibenzodioxocinones, which are inhibitors of cholesterol ester transfer protein (CETP), and as purpactins A and C', inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). Strain NK17 can make a fairly high yield of pestalotiollide B (i.e., up to 7.22 mg/l) in a constitutive manner in liquid culture. Moreover, we found that a putative histone deacetylase gene, designated as hid1, played a role in the biosynthesis of pestalotiollide B. In the hid1 null mutant, the yield of pestalotiollide B increased approximately 2-fold to 15.90 mg/l. In contrast, deletion of gene hid1 led to a dramatic decrease of conidia production of the fungus. These results suggest that hid1 is a modulator, concerting secondary metabolism and development such as conidiation in P. microspora. Our work may help with the investigation into the biosynthesis of pestalotiollide B and the development for new CETP and ACAT inhibitors.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2403-2407
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• 2009

Second-order rate constants have been measured for two series of nucleophilic displacement reactions, i.e., reactions of 4-nitrophenyl benzoate with Z-substituted phenoxides and those of Y-substituted phenyl benzoates (1a-h) with 4-chlorophenoxide (4-ClPhO–) in 80 mol% $H_2O$/20 mol% DMSO at 25.0 ${\pm}\;0.1\;{^{\circ}C}$. The Br$\phi$nsted-type plot for reactions of 4-nitrophenyl benzoate with Z-substituted phenoxides exhibits an excellent linear correlation with ${\beta}_{nuc}$ = 0.72. Reactions of 1a-h with 4-chlorophenoxide result in also a linear Br$\phi$nsted-type plot with ${\beta}_{lg}$ = –0.62, a typical ${\beta}_{lg}$ value for a concerted mechanism. The Hammett plots correlated with ${\sigma}^o\;and\;{\sigma}^-$ constants show many scattered points for reactions of 1a-h with 4-chlorophenoxide. In contrast, the corresponding Yukawa-Tsuno plot exhibits an excellent linear correlation with $\rho_Y$ = 2.26 and r = 0.53, indicating that expulsion of the leaving group occurs at the rate-determining step (RDS) either in a concerted mechanism or in a stepwise pathway. However, a stepwise mechanism with leaving group departure being the RDS is excluded since the leaving Y-substituted phenoxide is less basic and a better nucleofuge than the incoming 4-ClPh$O^-$. Thus, the reactions have been concluded to proceed through a concerted mechanism, in which bond formation between the nucleophile and electrophilic center is more advanced than expulsion of the leaving group in the transition state on the basis of the magnitude of ${\beta}_{nuc}\;and\;{\beta}_{lg}$ values.

• 한국수정란이식학회지
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• 제25권1호
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• pp.29-34
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• 2010

난포낭종은 소 번식 장애의 주요 원인 중의 하나이며, 다양한 유전자의 변화는 여러 세포와 조직 기능에 영향을 준다. 이러한 유전자 변화는 낭종성 난소에서도 나타날 수 있다. 이온 및 수송체와 관련된 유전자 변화가 한우의 난포낭종을 유발할 수 있을 것이라는 가설 하에 난포낭종성 난포에서 발현 변화를 보이는 유전자를 찾기 위하여 마이크로어레이 분석을 수행하였다. 마이크로어레이 분석 결과, 난포낭종성 난포에서 FGG와 LRP8이 증가하고, SLC44A4, SLC27A5, ANXA8 및 aquaporin 4는 감소하였다. 반정량적 역전사중합효소 연쇄 반응으로 마이크로어레이 분석 결과를 재확인하였다. 6개의 DEG 중 3개의 DEG(FGG, SLC44A4 및 aquaporin 4)는 마이크로어레이 분석 결과와 동일하게 증가와 감소를 보였다. 마이크로어레이와 역전사중합효소 반응에서 동일한 결과를 보이는 3개의 유전자 중 가장 크게 변화를 보인 섬유소원에 중점을 두고 연구를 수행하였다. 마이크로어레이와 역전사중합효소 연쇄 반응은 난포낭종성 난포에서 섬유소원 유전자 발현을 각각 8.4배와 1.7배 증가시켰다. 그러나 난포 및 과립층세포에서 섬유소원의 단백질 양은 웨스턴 블랏 분석으로 분석한 결과, 정상에 비하여 낭종에서 유의한 차이를 보이지 않았다. 본 연구에서 섬유소원은 유전자와 단백질 발현에 있어 상관관계는 보이지 않았지만 섬유소원 유전자는 정상 조직으로부터 난포낭종을 구별하는데 있어서 중요한 생물표지자가 될 수 있는 가능성을 제시한다.

• Fisheries and Aquatic Sciences
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• 제22권12호
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• pp.30.1-30.11
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• 2019

Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2, and CAI-1. Bioassay-guided purification of F. cf reticulata extract was conducted on two bacterial species, i.e., Tenacibaculum maritimum and V. harveyi for antibiotic and QS inhibition bioactivities. Toxicity bioassay of fractions was also evaluated on the freshwater fish Poecilia reticulata and the marine fish Acanthurus triostegus. Cyclohexanic and dichloromethane fractions of F. cf reticulata exhibited QS inhibition on V. harveyi and antibiotic bioactivities on V. harveyi and T. maritimum, respectively. Palauolide (1) and fascaplysin (2) were purified as major molecules from the cyclohexanic and dichloromethane fractions, respectively. Palauolide inhibited QS of V. harveyi through HAI-1 QS pathway at 50 ㎍ ml^-1 (26 μM), while fascaplysin affected the bacterial growth of V. harveyi (50 ㎍ ml^-1) and T. maritimum (0.25 ㎍). The toxicity of fascaplysin-enriched fraction (FEF) was evaluated and exhibited a toxic effect against fish at 50 ㎍ ml^-1. This study demonstrated for the first time the QSI potential of palauolide (1). Future research may assess the toxicity of both the cyclohexanic fraction of the sponge and palauolide (1) on fish, to confirm their potential as alternative to antibiotics in fish farming.

• 대한화학회지
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• 제67권3호
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• pp.191-198
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• 2023

본 연구에서는 2,4-dinitrophenyl-5-substituted-2-furoates (1a-d)와 R₂NH/R₂NH₂⁺-20 mol%DMSO(aq)의 아실 이동 반응을 반응속도론적으로 연구하였다. 이 반응은 이차반응이고, pK_a⁰ = 9.5, β₁= 0.23-0.35 및 β₂ = 0.88-0.99의 결과와 함께 아래 방향으로 굽은 Brönsted plots이 관측되었다. k₁값은 5-furyl 치환기의 전자끄는 능력이 증가하고 친핵체의 친핵성도가 커질수록 증가하였다. 반면, k₂/k_-1 값 비율은 5-furyl 치환기에 관계없이 거의 일정하였다. 실험결과로 부터 반응은 속도결정단계가 변하는 단계반응 메커니즘으로 진행됨을 제안하였다.