• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.111-113
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• 1986

The axial alcohol in trans-3,3,5-trimethylcyclohexanol was oxidized more readily than the equatorial alcohol in cis-3,3,5-trimethylcyclohexanol by NBS in aqueous dioxane. On the contrary, the equatorial alcohol was preferentially oxidized to the axial one by 10% aqueous sodium hypochlorite in the presence of tetrabutylammonium hydrogen sulfate (TBHS). The specificity indicates the presence of two different mechanism. In acidic medium, the cleavage of C-H bond is rate determining step while the reactivity of the alcohol is important in the presence of TBHS. The mechanism in basic medium without TBHS will be discussed.

• 한국의류학회지
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• 제13권1호
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• pp.59-66
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• 1989

This paper is concerned with formaldehyde release from durable press finished rayon fabrics. $100\%$ rayon fabrics were treated with 3 kinds of commercial N-methylol crosslinking agents using a pad-dry cure technique. Aqueous extractions of fabric samples were carried out at $40^{\circ}C$ under pH's of 4, 7, 10. Formaldehyde release was evaluated for the types of resins, catalyst concentrations and extraction conditions. Results indicated that the higher concentration of catalyst leads to the more fixation of resin on the fabric. Total formaldehyde released to the extract was decreased as the catalyst concentration increased. For the resin types, the amount of formaldehyde released was in the order of DMU>MDMDHEU>DMDHEU. Free formaldehyde content in the extract was in the order of pH10>pH4>pH7. This result proved that resins are least resistant to alkaline hydrolysis and the N-C bond cleavage under alkaline condition. Under acidic condition, however, N-methylol formaldehyde was accumulated before the release of free formaldehyde. This suggested the C·0 bond cleavalge to form carbonium - immonim intermediate.

• 한국동물생명공학회지
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• 제35권4호
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• pp.357-365
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• 2020

The aim of present study was to investigate regulatory mechanism of alpha-linolenic acid (ALA) during in vitro maturation (IVM) on nuclear and cytoplasmic maturation of porcine oocytes. Basically, immature cumulus-oocyte complexes (COCs) were incubated for 22 h in IVM-I to which hormone was added, and then further incubated for 22 h in IVM-II without hormone. As a result, relative cumulus expansion was increased at 22 h after IVM and it was enhanced by treatment of ALA compared with control group (p < 0.05). During IVM process within 22 h, cAMP level in oocytes was decreased at 6 h (p < 0.05) and it was recovered at 12 h in ALA-treated group, while oocytes in control group recovered cAMP level at 22 h. In cumulus cells, it was reduced in all time point (p < 0.05) and ALA did not affect. Treatment of ALA enhanced metaphase-I (MI) and MII population of oocytes compared with oocytes in control group at 22 and 44 h, respectively (p < 0.05). Intracellular GSH levels in ALA group was increased at 22 and 44 h after IVM (p < 0.05), whereas it was increased in control group at 44 h after IVM (p < 0.05). In particular, the GSH in ALA-treated oocytes during 22 h of IVM was higher than control group at 22 h (p < 0.05). Lipid amount in oocytes from ALA group was higher than control group (p < 0.05). Treatment of ALA did not influence to absorption of glucose from medium. Cleavage and blastocyst formation of ALA-treated oocytes were enhanced compared with control group (p < 0.05). These findings suggest that supplementation of ALA could improve oocyte maturation and development competence through increasing GSH synthesis, lipid storage, and regulation of cAMP accumulation during early 22 h of IVM, and these might be mediated by cumulus expansion.

• Journal of Microbiology
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• 제34권4호
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• pp.305-310
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• 1996

A microorganism producing carboxymethyl-cellulase (CMCase) was isolated from 300 soil and compost samples. The isolate was identified as Bacillus sp. by $Biolog^{TM}$ test and fatty acid analysis, and named as Bacillus sp. KD1014. The isolate could degrade, in addition to CMC, various kinds of polysaccharides such as levan, xylan, starch, and filter paper but hardly degrade microcrystalline Avicel. The optimum growth and CMCase production of the isolate was observed between 16-and 25 hr-culture at 45$^{\circ}C$ and pH 5.0. The maximum CMCase activity was observed at pH 4.5 and 6$0^{\circ}C$. The CMCase was found to bind to Avicel. The CMCase was internally cleaved as growth continued. When crude supernatant was used for activity staining, three major bands were detected on a native gel, however, only one major band was detected on a denaturating gel after removal of the detergent.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.

• 한국식품영양학회지
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• 제9권4호
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• pp.490-495
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• 1996

홑파래로부터 황산기를 함유한 다당체를 크로마토그래프로 분리정제하여 rhamnan sulfate가 항보체 활성화에 미치는 영향을 조사하였다. 항보체 활성능력은 F-4-3 획분을 비교군으로 Heparin H-180, Dextran과 비교해 결과 비교군보다 높았고, C4a와 C3a의 C convertase의 형성과 기능을 F-4-3 획분이 억제하였다. 이러한 보체 활성화 양식은 classical pathway 및 alternative pathway로도 경유함을 알 수 있었다.

• Reproductive and Developmental Biology
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• 제38권4호
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• pp.147-158
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• 2014

Differentiated nuclei can experimentally be returned to an undifferentiated embryonic status after nuclear transfer (NT) to unfertilized metaphase II (MII) oocytes. Nuclear reprogramming is triggered immediately after somatic cell nucleus transfer (SCNT) into recipient cytoplasm and this period is regarded as a key stage for optimizing reprogramming. In a recent study (Dai et al., 2010), use of m-carboxycinnamic acid bishydroxamide (CBHA) as a histone deacetylase inhibitor during the in vitro early culture of murine cloned embryos modifies the acetylation status of somatic nuclei and increases the developmental competence of SCNT embryos. Thus, we examined the effects of CBHA treatment on the in vitro preimplantation development of porcine SCNT embryos and on the acetylated status of histone H3K9 on cloned embryos at the zygote stage. We performed the three groups SCNT: SCNT (NT), CBHA treatment at the porcine fetus fibroblast cells (PFFs) used as donor cells prior to SCNT (CBHA-C) and CBHA treatment at the porcine SCNT embryos during the in vitro early culture after oocyte activation (CBHA-Z). The PFFs were treated with a $15{\mu}M$ of CBHA (8 h) for the early culture and the porcine cloned embryos were treated with a $100{\mu}M$ concentration of CBHA during the in vitro early culture (10 h). Cleavage rates and development to the blastocyst stage were assessed. No significant difference was observed the cleavage rate among the groups (82.6%, 76.4% and 82.2%, respectively). However, the development competence to the blastocyst stage was significantly increased in CBHA-Z embryos (22.7%) as compared to SCNT and CBHA-C embryos (8.6% and 4.1%)(p<0.05). Total cell numbers and viable cell numbers at the blastocyst stage of porcine SCNT embryos were increased in CBHA-Z embryos as compared to those in CBHA-C embryos (p<0.05). Signal level of histone acetylation (H3K9ac) at the zygote stage of SCNT was increased in CBHA-Z embryos as compared to SCNT and CBHA-C embryos. The results of the present study suggested that treatment with CBHA during the in vitro early culture (10 h) had significantly increased the developmental competence and histone acetylation level at the zygote stage.

• Bulletin of the Korean Chemical Society
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• 제13권6호
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• pp.588-592
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• 1992

A series of new ferrocene derivatives containing cyclohexylphosphines have been prepared from the reactions of lithioferrocenes with corresponding chlorodicyclohexylphosphines. 1-diphenylphosphino-1'-dicyclohexylphosphinoferro cene has been prepared from [1]-ferrocenophane via a ring cleavage reaction. Chiral ferrocenylaminophosphines incorporating cyclohexyl-and cyclopentadienylphosphines have also been prepared from the chiral template 2-N,N-dimethylaminoethylferrocene (FA) via stereoselective lithiation followed by phosphination with corresponding $R_2PCl$(R= $C_6H_{11}$, $C_5H_5$). The synthesis of cyclopentadienylphosphine derivative of (R)-FA (6b) led to the formation of a mixture of four diastereomers due to the presence of three chiral sources in the final product in addition to the fluxional behavior of the $η^1$-$C_5H_5$ group attached to the phosphorus. All these new compounds have been characterized by analytical and spectroscopic techniques.

• 대한화학회지
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• 제37권3호
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• pp.287-293
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• 1993

n-헥산과 아세톤 용매내에서 요오드와 테트라메틸주석간의 전하이동 상호작용을 분광학적 방법으로 연구하였다. 이들의 결과로부터 일시적인 전하이동착물의 흡수 스펙트럼이 관찰되었으며, 흡수 스펙트럼의 후속적인 감소현상이 요오드에 의한 테트라메틸주석의 분해반응임을 알았다.(iododestannylation). 따라서 iododestannylation에 대한 속도상수를 온도 10, 25 및 35$^{\circ}C$, 압력을 1600 bar까지 변화시켜 가면서 측정하였으며, 이때의 반응속도상수는 온도와 압력에 따라 증가함을 알았다. 이 반응속도상수로부터 ${\Delta}V^{\neq}$, ${\Delta}{\beta}^{\neq}$, ${\Delta}H^{\neq}$ 및 ${\Delta}S^{\neq}$의 값을 얻었으며, 이들 값으로부터 전이상태의 용매구조 변화 및 메카니즘을 규명하였다. 이러한 사실로부터 본 반응은 S$_F$2 메카니즘이 지배적이며 압력이 증가함에 따라 S$_F$2의 성격이 약화됨을 알았다.

• Applied Biological Chemistry
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• 제31권2호
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• pp.137-142
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• 1988

Saccharomycopsis lipolytica ATCC 44601에서 정제한 isocitrate lyase 반응산물의 축합반응과 개열반응은 $30^{\circ}C$, pH 7.0에서 분석되었다. Glyoxylate와 succinate의 축합반응에서 Km값은 각각 0.06 mM과 0.21 mM이었고, 개열 반응에서 glyoxylate는 직선적인 경쟁적 저해를, succinate는 직선적인 비경쟁적 저해를 나타내었으며 이때 Ki 값은 각각 0.22 mM과 0.82 mM이었다. 그러므로 이 kinetic분석은 이 효소가 축합 반응에서 glyoxylate가 succinate보다 먼저 결합하는 정서반응기구인 것을 나타내었다. 3-Bromopyruvate(BrP)의 불활성화는 포화 kinetics를 나타내면서 효소를 불가역적으로 불활성화하였으며 반감기는 0.15분이고 $K_{BrP}$는 0.032 mM이었으며, 기질과 반응생성물들을 불활성화에 대하여 보호작용이 있었다.