• 대한화학회지
• /
• 제17권2호
• /
• pp.95-104
• /
• 1973

일련의 염화알킬(염화메틸, 에틸, 이소-프로필, 트란스 n-부틸, sec-부틸, tert-부틸)의 바닥 상태 전자구조와 친핵성 치환반응성을 근사적 시그마 분자궤도법$(\sigma-MO)$인 EHT 와 CNDO/2 법을 이용하여 비교 검토하였다. 염화알킬처럼 상호 구조적 차이가 현저하지 못한 경우에 있어서는 EHT법이 CNDO/2 법에 비하여 비교적 부정확함을 알았다. CNDO/2 계산에 의하면, 쌍극자모멘트의 계산치가 실험치 보다 약간 크게 주어지며 대체로 primary$\alpha$탄소와 Cl사이에 비교적 약한 $\pi$-반결합 $({\pi}^{\ast})$성을 가지고 있으며, 전자밀도가 거의 염소원자에 집중되어 있어 염소의 p-고립상 전자와 같은 특성을 가지고 있음을 알았다. 그 반면 최저 비점유 궤도함수(LUMO)는$\alpha$탄소와 염소 사이에 강한 시그마-반결합$({\alpha}^{\ast})$성을 가짐을 알았다. 염화알킬의 $S_N2$반응성은 주로 $\alpha$인 LUMO에의하여 좌우되며, 특히 이 MO에서 $\alpha$탄소와 염소간의 반결합 세기가 $S_N2$반응성의 척도가 될 것으로 예측되며, 결합-polorizability와의 관련성도 논의하였다. 염화알킬의 $S_N2$반응성은 주로 ${\pi}^{\ast}$인 HOMO에서 $\alpha$탄소와 염소간의 반결합 세기가 큰 역할을 하며 바닥상태의 C-Cl결합세기도 상당한 역할을 할 것으로 기대된다.

• Bulletin of the Korean Chemical Society
• /
• 제33권2호
• /
• pp.629-635
• /
• 2012

Two novel conjugated copolymers utilizing 4,7-dithien-2-yl-2,1,3-benzothiadiazole (DTBT) coupled with cyano (-CN) substituted vinylene, as the electron deficient moeity, have been synthesized and evaluated in bulk heterojunction solar cell. The electron deficient moeity was coupled with carbazole and fluorene unit by Knoevenagel condition to provide poly(bis-2,7-((Z)-1-cyano-2-(5-(7-(2-thienyl)-2,1,3-benzothiadiazol-4-yl)-2-thienyl)ethenyl)-alt-9-(1-octylnonyl)-9H-carbazol-2-yl-2-butenenitrile) (PCVCNDTBT) and poly(bis-2,7-((Z)-1-cyano-2-(5-(7-(2-thienyl)-2,1,3-benzothiadiazol-4-yl)-2-thienyl)ethenyl)-alt-9,9-dihexyl-9H-fluoren-2-yl) (PFVCNDTBT). The optical band gaps of PCVCNDTBT (1.74 eV) and PFVCNDTBT (1.80 eV) are lower than those of PCDTBT (1.88 eV) and PFVDTBT (2.13 eV), which is advantageous to provide better coverage of the solar spectrum in the longer wavelength region. The high $V_{oc}$ value of the PSC of PCVCNDTBT (~0.91 V) is attributed to its lower HOMO energy level ( 5.6 eV) as compared to PCDTBT ( 5.5 eV). Bulk heterojunction solar cells based on the blends of the polymers with [6,6]phenyl-$C_{61}$-butyric acid methyl ester ($PC_{61}BM$) gave power conversion efficiencies of 0.76% for PCVCNDTBT under AM 1.5, 100 mW/$cm^2$.

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권1호
• /
• pp.126-133
• /
• 2016

A gene from Actinomyces sp. Korean native goat (KNG) 40 that encodes an endo-${\beta}$-1,4-glucanase, EG1, was cloned and expressed in Escherichia coli (E. coli) $DH5{\alpha}$. Recombinant plasmid DNA from a positive clone with a 3.2 kb insert hydrolyzing carboxyl methyl-cellulose (CMC) was designated as pDS3. The entire nucleotide sequence was determined, and an open-reading frame (ORF) was deduced. The ORF encodes a polypeptide of 684 amino acids. The recombinant EG1 produced in E. coli $DH5{\alpha}$ harboring pDS3 was purified in one step using affinity chromatography on crystalline cellulose and characterized. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis/zymogram analysis of the purified enzyme revealed two protein bands of 57.1 and 54.1 kDa. The amino terminal sequences of these two bands matched those of the deduced ones, starting from residue 166 and 208, respectively. Putative signal sequences, a Shine.Dalgarno-type ribosomal binding site, and promoter sequences related to the consensus sequences were deduced. EG1 has a typical tripartite structure of cellulase, a catalytic domain, a serine-rich linker region, and a cellulose-binding domain. The optimal temperature for the activity of the purified enzyme was $55^{\circ}C$, but it retained over 90% of maximum activity in a broad temperature range ($40^{\circ}C$ to $60^{\circ}C$). The optimal pH for the enzyme activity was 6.0. Kinetic parameters, $K_m$ and $V_{max}$ of rEG1 were 0.39% CMC and 143 U/mg, respectively.

• The Korean Journal of Physiology and Pharmacology
• /
• 제19권5호
• /
• pp.435-440
• /
• 2015

This study aimed to investigate the effect of pituitary adenylate cyclase-activating peptide (PACAP) on the pacemaker activity of interstitial cells of Cajal (ICC) in mouse colon and to identify the underlying mechanisms of PACAP action. Spontaneous pacemaker activity of colonic ICC and the effects of PACAP were studied using electrophysiological recordings. Exogenously applied PACAP induced hyperpolarization of the cell membrane and inhibited pacemaker frequency in a dose-dependent manner (from 0.1 nM to 100 nM). To investigate cyclic AMP (cAMP) involvement in the effects of PACAP on ICC, SQ-22536 (an inhibitor of adenylate cyclase) and cell-permeable 8-bromo-cAMP were used. SQ-22536 decreased the frequency of pacemaker potentials, and cell-permeable 8-bromo-cAMP increased the frequency of pacemaker potentials. The effects of SQ-22536 on pacemaker potential frequency and membrane hyperpolarization were rescued by co-treatment with glibenclamide (an ATP-sensitive $K^+$ channel blocker). However, neither $N^G$-nitro-L-arginine methyl ester (L-NAME, a competitive inhibitor of NO synthase) nor 1H-[1,2,4]oxadiazolo[4,3-${\alpha}$]quinoxalin-1-one (ODQ, an inhibitor of guanylate cyclase) had any effect on PACAP-induced activity. In conclusion, this study describes the effects of PACAP on ICC in the mouse colon. PACAP inhibited the pacemaker activity of ICC by acting through ATP-sensitive $K^+$ channels. These results provide evidence of a physiological role for PACAP in regulating gastrointestinal (GI) motility through the modulation of ICC activity.

• 한국발생생물학회:학술대회논문집
• /
• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
• /
• pp.81-81
• /
• 2003

DNA methylation is a covalent modification of DNA that can modulate gene expression and is now recognized as a major component of the epigenome. During evolution, the dinucleotide CpG has been progressively eliminated from the genome of higher eukaryotes and is present at only 5% to 10% of its predicted frequency. Approxymately 80% of the remaining CpG sites contain methylated cytosines in most vertebrates and they are distributed in a pattern that is unique in each tissue and is inversely correlated with gene expression. The pattern of methylation is faithfully maintained during cell division by the enzyme Dnmt1, the maintenance DNA methyltransferase, which catalyzes the transfer of a methyl group from S-adenosyl-methionine to the 5'-position of the cytosine ring. We have been identified bovine Dnmt1 cDNA full-length recently (AY173048) Little is known on the functions of Dnmt1 in bovine preimplantation embryos. Thus, we analyzed the specific pattern of Dnmt1 in in vitro derived/nuclear transfer bovine and in vivo derived mouse embryos to monitor the epigenetic reprogramming process. We investigated these process by using indirect immunofluresence with an antibody to Dnmt1. According to other studies, Dnmt1 accumulates in nuclei of early growing oocytes but is sequestered in the cytoplasm of mature oocytes. In 2-cell and 4-cell embryos, Dnmt1 is cytoplasmic, but at the 8-cell stage, it is present only in the nucleus. By the blastocyst stage, Dnmt1o is again found only in the cytoplasm. Thus, nuclear localization of Dnmt1o in preimplantation embryos is limited to the 8-cell stages After implantation, Dnmt1 is localized in the nucleus in mouse. However, we have found different patterns of Dnmt1 nuclear localization. Though we used the common antibody, immune-localization data revealed that Dnmt1 antibody have been detected at the nucleus in 1-cell to blastocyst embryos. Therefore, maybe we think that the functions of Dnmt1 between bovine and mice are different. In order to Identify the mechanisms that regulate DNA methylation in bovine preimplantation embryo, we have plans on using bovine oocyte and somatic specific Dnmt1 antibodies.

• The Korean Journal of Physiology and Pharmacology
• /
• 제26권6호
• /
• pp.531-540
• /
• 2022

Group 1 metabotropic glutamate receptors (mGluRs) can positively affect postsynaptic neuronal excitability and epileptogenesis. The objective of the present study was to determine whether group 1 mGluRs might be involved in synaptically-induced intracellular free Ca²⁺ concentration ([Ca²⁺]_i) spikes and neuronal cell death induced by 0.1 mM Mg²⁺ and 10 µM glycine in cultured rat hippocampal neurons from embryonic day 17 fetal Sprague-Dawley rats using imaging methods for Ca²⁺ and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays for cell survival. Reduction of extracellular Mg²⁺ concentration ([Mg²⁺]_o) to 0.1 mM induced repetitive [Ca²⁺]_i spikes within 30 sec at day 11.5. The mGluR5 antagonist 6-Methyl2-(phenylethynyl) pyridine (MPEP) almost completely inhibited the [Ca²⁺]_i spikes, but the mGluR1 antagonist LY367385 did not. The group 1 mGluRs agonist, 3,5-dihydroxyphenylglycine (DHPG), significantly increased the [Ca²⁺]_i spikes. The phospholipase C inhibitor U73122 significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The IP₃ receptor antagonist 2-aminoethoxydiphenyl borate or the ryanodine receptor antagonist 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate also significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The TRPC channel inhibitors SKF96365 and flufenamic acid significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The mGluR5 antagonist MPEP significantly increased the neuronal cell survival, but mGluR1 antagonist LY367385 did not. These results suggest a possibility that mGluR5 is involved in synaptically-induced [Ca²⁺]_i spikes and neuronal cell death in cultured rat hippocampal neurons by releasing Ca²⁺ from IP₃ and ryanodine-sensitive intracellular stores and activating TRPC channels.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권1호
• /
• pp.36-40
• /
• 2007

Proteins and lipids not only provide a source of energy to the cell, but also play vital roles in modifying the physical properties and function of the biological membranes. In the present study, we investigated the biochemical constituents, viz. proteins and lipids, in growing oocytes of goat antral follicles during summer and winter seasons. Goat genitalia in phosphate buffered saline (pH 7.4) were brought to the laboratory within one hour of slaughter under aseptic conditions at $37^{\circ}C$. Oocytes were aspirated from normal small (<3 mm in diameter) and large (>3 mm) follicles and pooled for biochemical estimations. A significant increase in the amount of protein and lipid was observed with the growth of the oocyte. The amount of protein varied non-significantly with the season, while the amount of lipid varied significantly. The amounts of phospholipid, cholesterol, free fatty acid, and triglyceride increased with the growth of the oocyte, but no significant effect of season in these constituents was observed. Lysolecithin, sphingomyelin, and sterols were the polar lipids identified in both oocytes prepared from small follicles (small oocytes) as well as large follicles (large oocytes). In addition, the small oocytes also contained phosphatidyl serine, while large oocytes contained phosphatidyl glycerol phosphate and phosphatidyl inositol. Among non-polar lipids, triglycerides and long chain alcohols appear only in small oocytes and not in large oocytes. Monoglycerides, 1,2-diglycerides, 1,3-diglycerides and o-dialkyl glycerol ethers, fatty acids, fatty acid methyl esters, and wax esters were identified in both small and large oocytes. Information on biochemical composition of growing oocytes is relevant to oocyte and embryo competence, culture and cryopreservation.

• Journal of Ginseng Research
• /
• 제14권2호
• /
• pp.317-331
• /
• 1990

Nitrogen compounds of Panax ginseng and their biological activities in plant and animal were reviewed. Major nitrogen combounds found in P. ginseng are free amino acids, Water soluble teins, insoluble proteins and peptides. Minor nitrogen compounds are dencichine. glycol)roteins. amines, alkaloides, methoxy or alkyl pyrazine derivatives. free nucleosides and nllrleir arid bases. 4-me- thymi-5-thiazoleethanol and pyroglutamic acid. The contents of total nitrogen and protein in root increased until 13 years old rvhich was the highest age tinder investigation. Soluble protein content increased With the root weight and was higher in xylem pith than cortex-epidermis indicating the rlosc relation with root growth. Arginine which covered 58% of total free amino aroids may serve as a storage nitrogen. Arginine seems to be changed into proline in rhizome, threonine in stem and again threoning and arginine in leaf. The greater the root weight the higher the polyaminc content. Polyamine stimulated the growth of root callus. Physiological roles of other minor nitrogen compounds are unknown although dencichine content is relatively high (0.5% d.w.). biochemical and pharmatological activities of some nitrogen compounds for animal were more investigated than physiological roll iota plant itself. Radiation and U.V. protective function (heat stable protein), insulin-like activity in lipogenesis and lipolysis (adenosine and pyroglutamic acid), depression of blood sugar content (glycopeptide). hemostatir and nellrotoxic activity (denrichine) and. sedative and hypnotic activity (4-methyl-5-thiazoleethilnol) are reported. Heat stable protein increased with root age. The traditional quality critsria appear to be well in accordance with biological activities of nitrogen compounds. Chemical stlldies of nitrogen compounds seem relatively rare, probably dole to difficulty of isolation, subsequently the investigations of biological activities are little.

• Natural Product Sciences
• /
• 제22권4호
• /
• pp.238-245
• /
• 2016

Gumiganghwal-tang has been used for the treatment of common cold for a long-time. We developed an accurate and sensitive high performance liquid chromatography-diode array detection (HPLC-DAD) and electrospray ionization mass spectrometry method for the simultaneous determination of ferulic acid, baicalin, bergapten, methyl eugenol, glycyrrhizin, oxypeucedanin, wogonin, nodakenin, atractylenolide III, imperatorin, and atractylenolide I in Gumiganghwal-tang samples. The analytes were separated on a Shiseido C18 column ($5{\mu}m$, $4.6mm\;I.D.{\times}250mm$) with gradient elution with acetonitrile and 0.1% trifluoroacetic acid. Eleven compounds were quantitatively determined by HPLC-DAD and identified by LC-MS data. We also validated this method. The calibration curves of all the compounds showed good linear regression. The limits of detection and the limits of quantification ranged from 0.04 to 0.63 and from 0.12 to $1.92{\mu}g/mL$, respectively. The relative standard deviation values of intra- and inter-days of this method represented less than 2.9%. The recoveries were found to be in the range of 90.06 - 107.66%. The developed method has been successfully applied to the analysis of Gumiganghwaltang samples. The established HPLC method could be used to quality control of Gumiganghwal-tang.

• 대한한방내과학회지
• /
• 제25권2호
• /
• pp.277-287
• /
• 2004

Objective : Diabetes is a disease in which the body does not produce or properly use insulin. Etiological studies of diabetes and its complications showed that oxidative stress might playa major role. Therefore, many efforts have been made to regulate oxygen free radicals for treating diabetes and its complications. Because Jindangwon has been known to be effective in treatment of diabetes, the methanol extract of Jindangwon was tested for its effectiveness in reducing the oxidative stress induced by Streptozotocin. Methods : Jindangwon was washed, dried in the shade and crushed. The crushed Jindangwon was extracted 3 times, each time with 3 volumes of methyl alcohol at $60^{\circ}C$ for 24 hours. The extract was filtered and evaporated under reduced pressure using a rotary evaporator to yield 30.6 g. Jindangwon extract was oral-administered to the diabetic rats induced by streptozotocin 50 mg per 1 kg of body weight for 15 days. The efficacy of the Jindangwon extract was examined with regard to the enzymatic pathways involved in the oxygen free radical production and the glutathione balance. Results : he effects of the methanol extract of Jindangwon in streptozotocin-induced diabetics rats with regard to body weight, blood glucose level, hepatic lipid peroxide level, hepatic xanthine oxidase activity and type conversion rate, hepatic glutathione level, hepatic glutathione peroxidase activity, hepatic glutathione reductase activity, hepatic aldose reductase activity, and hepatic sorbitol dehydrogenase activity were favorable enough to suggest that it is a cure for diabetes and its complications. Conclusions :These results support Jindangwon as an effective reducing agent for oxidative stress in the tissues and organs by regulating the production of oxygen free radicals. Jindangwon, in particular, shows promising results for its use as a cure, or preventative medicine for diabetes and its complications by reducing oxidative stress in beta-cells of the pancreas.