• 한국염색가공학회지
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• 제35권4호
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• pp.239-245
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• 2023

Cellulose is an abundant biodegradable material in nature with excellent properties, but due to its poor processability, it has been widely studied for processing through modification. Cellulose acetate propionate (CAP) is a cellulose derivative in which the hydroxyl group of cellulose is replaced by acetyl and propionyl groups. CAP has several advantages, such as excellent solubility, structural stability, light and weather resistance, and good transparency. Porous nanofibers with excellent specific surface area, which can be applied in various fields, can be easily formed by the phase separation method using highly volatile solvents. High speed centrifugal spinning is a nano/micro fiber preparation method with advantages such as fast spinning and easy alignment control. In this study, a CAP/polybutylene succinate (PBS) spinning solution with chloroform as solvent was prepared to prepare porous microfibers and the fiber morphology was examined as a function of the disk rotation speed in an high speed centrifugal spinning device.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.281-288
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• 2002

Recombinant Escherichia coli strain harboring the ${\lambda}$pR-pL promotor and heterologus poly-${\beta}$-hydroxybutyrate (PHB) biosynthesis genes was used to investigate the effect of culture conditions on the efficient PHB production. The expression of phb genes was induced by a temperature upshift from $33^{\circ}C\;to\;38^{\circ}C$. The protein expression levels were measured by using two-dimensional electrophoresis, and the enzyme activities were also measured to understand the effect of culture temperature, carbon sources, and the dissolved oxygen (DO) concentration on the metabolic regulations. AcetylCoA is an important branch point for PHB production. The decrease in DO concentration lowers the citrate synthase activity, thus limit the flux toward the TCA cycle, and increase the flux for PHB production. Since NADPH is required for PHB production, the PHB production does not continue leading the overproduction of acetate and lac-tate. Based on these observations, a new operation was considered where DO concentration was changed periodically, and it was verified its usefulness for the efficient PHB production by experiments.

• Fibers and Polymers
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• 제2권2호
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• pp.86-91
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• 2001

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) [copoly(ET/CPT)] was prepared using poly(ethylene terephthalate) (PET) as a flexible spacer, terephthalic acid (TPA), and chlorohydroquinone diacetate (CHQDA). All reactions involved in the copolymerization were investigated using some model compounds: TAP was used for acidolysis, diphenylethyl terephthalate (DPET) for interchange reaction between PET chains, and 야-o-chlorophenyl terephthalate (DOCT) and di-m-chlorophenyl terephthalate (DMCT) for interchange reaction between PET and rigid rodlike segments. Activation energies obtained for the acidolysis of PET with TPA and for interchange reaction of PET with DPET, DOCT, and DMCT were 19.8 kcal/mol, 26.5 kcal/mole, and 45.9 kcal/mole, respectively. This result supports that the copolymerization proceeds through the acidolysis of PET with TPA first and subsequent polycondensation between carboxyl end group and CHQDA or acetyl end group, which is formed from the reaction of CHQDA and TPA. Also, it was found that ester-interchange reaction can be influenced by the steric hindrance. Copoly(ET/CPT)s obtained has ethylene acetate end groups formed from acetic acid hydroxy ethylene end groups and showed almost the random sequence distribution for all compositions.

• 대한약리학회지
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• 제10권1호
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• pp.55-59
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• 1974

Further elucidation of the mechanism of halothane's negative inotropic action has resulted from a study of the effect of various substrates on halothane-depressed rat atria. Approximately 6 mg% halothane was required to maintain a 50% depression of the contractility of rat atria suspended in a modified Krebs-Ringer bicarbonate glucose medium, pH 7.4, $30^{\circ}C$ for 2hr. Both lactate and acetate were found to restore partially the contractility of halothane-depressed atria. The maximally effective concentration of lactate was 5 mM; for acetate it was 2.5mM. Neither 5 nor 20 mM of additional glucose was effective in restoring the force of contraction of halothane-depressed atria. The results are consistent with the hypothesis that halothane exerts at least a part of its negative inotropic effect on rat atria by inhibiting either the uptake or utilization of glucose by the myocardium. The site of blockade must be prior to the conversion of pyruvate to acetyl CoA. In our previous report dealing with the mechanism of cardiac depressant action of inhalation anesthetic halothane, it has been demonstrated that: 1) approximately 6 mg/100 ml halothane is required to maintain 50% depression of the force of contraction of isolated rat atria in Krebs-Ringer bicarbonate glucose medium; 2) pyruvate partially restores the contractility of halothane-depressed atria, but has no effect on normal atria; the partial recovery of depressed atria by the addition of sodium pyruvate is due to the effect of the pyruvate ion itself, not to the sodium ion; 4) addition of pyruvate, to atria depressed with hypertonic medium, produced only further depression. From these findings we concluded that the cardiac depressant action of halothane on rat atria is a manifestation of inhibition of glucose uptake or utilization. The present studies were undertaken to observe the effect of other substrates on halothane-depressed atria in order to substantiate our conclusion. As with the case of pyruvate, lactate and acetate also partially restored the force of contraction of halothane-depressed atria. These data are consistent with the hypothesis that halothane inhibits glucose uptake or utilization in the glycolytic cycle of the myocardium.

• 한방재활의학과학회지
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• 제28권3호
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• pp.13-25
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• 2018

Objectives We investigated anti-obesity effects of essential oils extracted from Cnidii Rhizoma (CR) in immature adipocytes to magnify it's clinical therapeutic usage. Methods Essential oil of CR was extracted with ethyl acetate or petroleum ether and through steam distillation, respectively. Oil red-O staining for monitoring its inhibition effect on adipogenesis and differentiation in murine 3T3-L1 adipocytes and 3-(4,5-methylthiazol-2-yl)-2,5-diphenyletetra zolium bromide (MTT) assay for cell safety were done. Also phospho-adenosine monophosphate (AMP)-activted protein kinase (P-AMPK), AMP-activated protein kinase, phospho-acetyl-CoA carboxylase (P-ACC), acetyl-CoA carboxylase, peroxisome proliferator-activated receptor-${\alpha}$ (PPAR-${\alpha}$), peroxisome proliferator-activated receptor-${\gamma}$ (PPAR-${\gamma}$) and CCAAT/enhancer binding protein ${\alpha}$ (C/EBP-${\alpha}$) expressions as obesity-related factors were measured by western blot analysis. Results Protein expressions of P-AMPK, P-ACC and PPAR-${\alpha}$ were increased in essential oils-treated adipocytes compared to those of control group, respectively. Furthermore, protein expressions of PPAR-${\gamma}$ and C/EBP-${\alpha}$ were decreased in essential oils-treated adipocytes compared to those of control group, respectively. Conclusions These results demonstrate that essential oils of CR inhibit adipogenesis and differentiation. Also they promote the oxidation of fatty acids in adipocytes. Thus, results suggest that essential oils of CR could be used as a valuable material for anti-obesity therapeutics via control of lipid metabolism.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.36-36
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• 2017

Out of twenty common protein amino acids, there are many kinds of non protein amino acids (NPAAs) that exist as secondary metabolites and exert ecological functions in plants. Mimosine (Mim), one of those NPAAs derived from L. leucocephala acts as an iron chelator and reversely block mammalian cell cycle at G1/S phases. Cysteine (Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur-containing secondary products. Cys biosynthesis includes consecutive two steps using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast, and mitochondria. In the first step, the acetylation of the ${\beta}$-hydroxyl of L-serine by acetyl-CoA in the existence of SAT and finally, OASTL triggers ${\alpha}$, ${\beta}$-elimination of acetate from OAS and bind $H_2S$ to catalyze the synthesis of Cys. Mimosine synthase, one of the isozymes of the OASTLs, is able to synthesize Mim with 3-hydroxy-4-pyridone (3H4P) instead of $H_2S$ for Cys in the last step. Thus, the aim of this study was to clone and characterize the cytosolic (Cy) OASTL gene from L. leucocephala, express the recombinant OASTL in Escherichia coli, purify it, do enzyme kinetic analysis, perform docking dynamics simulation analysis between the receptor and the ligands and compare its performance between Cys and Mim synthesis. Cy-OASTL was obtained through both directional degenerate primers corresponding to conserved amino acid region among plant Cys synthase family and the purified protein was 34.3KDa. After cleaving the GST-tag, Cy-OASTL was observed to form mimosine with 3H4P and OAS. The optimum Cys and Mim reaction pH and temperature were 7.5 and $40^{\circ}C$, and 8.0 and $35^{\circ}C$ respectively. Michaelis constant (Km) values of OAS from Cys were higher than the OAS from Mim. Inter fragment interaction energy (IFIE) of substrate OAS-Cy-OASTL complex model showed that Lys, Thr81, Thr77 and Gln150 demonstrated higher attraction force for Cys but 3H4P-mimosine synthase-OAS intermediate complex showed that Gly230, Tyr227, Ala231, Gly228 and Gly232 might provide higher attraction energy for the Mim. It may be concluded that Cy-OASTL demonstrates a dual role in biosynthesis both Cys and Mim and extending the knowledge on the biochemical regulatory mechanism of mimosine and cysteine.

• 생명과학회지
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• 제28권8호
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• pp.885-891
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• 2018

급성위막성대장염(Pseudomembranous colitis)은 C. difficile 세균이 분비하는 톡신A에 의해 유발되는 것으로 알려져 있다. 톡신A에 의한 점막 상피세포의 장벽기능 감소가 발병 원인으로 알려져 있다. 최근 연구에 의하면 톡신 A는 대장상피세포 속 HDAC-6의 활성을 높여 튜블린의 탈아세틸화를 증가시키는 것으로 알려져 있다. 튜블린 단백질의 탈아세틸화는 미세소관 불 형성을 초래하여 점막 상피세포의 극단적인 세포 형태 변형을 야기하게 되며 결국 상피세포의 고유기능인 장벽 기능이 파괴된다고 알려져 있다. 최근 연구자 등은 potassium acetate가 톡신A에 의한 튜블린 탈아세틸화와 미세소관 불 형성을 회복시켜 장염을 유의하게 억제함을 보고하였다. 따라서 본 연구에서는 아세틸기를 포함하는 또 다른 간단한 화학구조의 초산을 적용하여 톡신A의 세포독성을 억제하는지 확인해보고자 하였다. 인간 대장상피세포에서 초산 자극은 튜블린 단백질의 아세틸화를 유의하게 증가시켰다. 또한 초산은 대장상피세포 속 미세소관 형성과정도 강하게 촉진시킴을 확인하였다. 초산은 톡신A에 의한 튜블린 탈아세틸화와 미세소관 불 형성 그리고 세포독성 모두를 유의하게 회복시켰다. 이상의 결과는 초산에 의한 미세소관 형성 촉진이 톡신A에 의해 초래되는 세포골격계 파괴와 그로 인한 세포독성을 억제할 수 있음을 보여준다. 따라서 초산이 톡신A의 작용을 차단하여 위막성대장염 증상을 완화시킬 수 있는 치료제로서 개발 가치가 있음을 보여준다.

• 한국식품과학회지
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• 제32권5호
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• pp.1015-1021
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• 2000

현재 재배되고 있는 흑미 중 수원 415호와 진도를 n-pentane과 diethylether 혼합용액(1:1, v/v)을 추출용매로 사용하여 SDE방법으로, 취반된 흑미로부터 휘발성 향기 성분을 추출하였다. 이 향기 추출물을 정제 농축하여 GC와 GC/MS로 분석한 후 GC 분석에 의한 RI 및 GC/MS 분석에 의한 mass spectrum을 표준물질의 분석 자료와 비교, 확인함으로써 휘발성 향기 성분을 동정하였고, 내부 표준물질을 이용하여 이들 성분을 정량하였다. 수원415호와 진도에서 각각 91, 82종의 화합물이 분리되었다. 수원415호에서는 alcohol류 26종, ketone류 15종, ester류 11종, aldehyde류 10종, hydrocarbon류 9종, acid류 5종, 황화합물 9종, 질소화합물 3종, furan 화합물 3종이었고 동정된 물질 중에서 hexadecanoic acid, acetic acid, 1,2-ethanediol, guaiacol, ethyl acetate, 2,3-dihydrobenzofuran, ethanol, ethyl hexadecanoate, methyl 9,12- octadecadienoate, hexanol, ethyl formate, hexanal, 2-pentanone이 수원 415호 흑미의 주요한 성분으로 확인되었다. 진도 흑미에서 분리 동정된 성분으로는 alcohol류 28종, ketone류 14종, ester류 12종, aldehyde류 9종, hydrocarbon류 5종, acid류 4종, 황화합물 4종, 질소화합물 3종, furan 화합물 3종이었고, hexadecanoic acid, guaiacol, acetic acid, 2,3-dihydrobenzofuran, hydroperoxy pentane, ethyl acetate, methyl 9,12-octadecadienoate, 2-nonanone, ethyl hexadecanoiate, ethyl formate, ethyl 9-octadecenoate, hexanol, 2-pentanone, 3-methyl-1-butanol이 동정되어 이러한 성분들이 진도 흑미의 주요한 성분으로 확인되었다. 미량이지만 향기의 발현에 영향을 미칠 것으로 생각하는 1-acetyl-2-pyrrolidone과 ${\alpha}-pyrrolidone$이 동정되었다.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.427-433
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• 2008

The cephabacins produced by Lysobacter lactamgenus are ${\beta}$-lactam antibiotics composed of a cephem nucleus, an acetate residue, and an oligopeptide side chain. In order to understand the precise implication of the polyketide synthase (PKS) module in the biosynthesis of cephabacin, the genes for its core domains, ${\beta}$-ketoacyl synthase (KS), acyltransferase (AT), and acyl carrier protein (ACP), were amplified and cloned into the pET-32b(+) expression vector. The sfp gene encoding a protein that can modify apo-ACP to its active holo-form was also amplified. The recombinant KS, AT, apo-ACP, and Sfp overproduced in the form of $His_6$-tagged fusion proteins in E. coli BL21(DE3) were purified by nickel-affinity chromatography. Formation of stable peptidyl-S-KS was observed by in vitro acylation of the KS domain with the substrate [L-Ala-L-Ala-L-Ala-L-$^3H$-Arg] tetrapeptide-S-N-acetylcysteamine, which is the evidence for the selective recognition of tetrapeptide produced by nonribosomal peptide synthetase (NRPS) in the NRPS/PKS hybrid. In order to confirm whether malonyl CoA is the extender unit for acetylation of the peptidyl moiety, the AT domain, ACP domain, and Sfp protein were treated with $^{14}C$-malonyl-CoA. The results clearly show that the AT domain is able to recognize the extender unit and decarboxylatively acetylated for the elongation of the tetrapeptide. However, the transfer of the activated acetyl group to the ACP domain was not observed, probably attributed to the improper capability of Sfp to activate apo-ACP to the holo-ACP form.

• Natural Product Sciences
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• 제23권2호
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• pp.113-118
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• 2017

A new tetracyclic triterpenoid [4,4,24-trimethylcholesta-${\Delta}^{8,9;14,5;24,28}$-trien-$3{\beta},11{\beta},12{\alpha}$-triol-12-acetate, 3-sulfate] sodium salt (1), together with eight known compounds including ergosterol $5{\alpha},8{\alpha}$-endoperoxide (2), 1,9-dihydroxy-3-methoxy-2-methylpterocarpan (3), 3-O-${\beta}$-D-2-acetyl-amino-2-deoxyglucopyranoxyloleanoic acid (4), hydnocarpin (5), derrone (6), isovitexin (7), erythrinin C (8), and 5,4'-dihydroxy-2"-hydroxyisopropyldihydrofurano [4,5:7,8]-isoflavone (9), were isolated from the EtOAc soluble fraction of the methanol extract of aerial part of Desmodium uncinatum collected in the western highland of Cameroon. The structures of these compounds were established by comprehensive interpretation of their spectral data mainly including 1D- ($^1H$ and $^{13}C$), 2D-NMR($^1H$-$^1H$ COSY, HMQC, HMBC) spectroscopic and ESI-TOF-MS mass spectrometric analysis. The isolation of an integracide-like compound from plant origin is a very unusual finding.