• The Korean Journal of Zoology
• /
• v.32 no.4
• /
• pp.404-411
• /
• 1989

In this study, we attempted to determine the precise patterns of protein synthesis during the second cleavage in mouse. F1 hybrid 2-cell embryos showing a highly synchronized cell cycle and outbreed ICR strain 2-cell embryos were used. The patterns of protein synthesis during the second cleavage showed the sequential changes in the F1 hybrid and ICR strain 2-cell embryos. Moreover, we examined the effects of mitotic and transcriptional inhibitors such as colcemid and a-amanitin on the protein synthesis in the late 2-cell embryos of ICR strain. Treatment of colcemid (0.1mg/ml) blocked the second cleavage, but did not affect on the change of protein synthesis. However, treatment of a-amanitin induced the synthesis of two set of polypeptides without affecting on synthesis of other proteins and cleavage. It thus seems that the appearance of a-amanitin-sensitive proteins may be not involved in the second cleavage. Therefore, these results indicate that the second cell cycle in mouse embryos appears to be regulated at post transcriptional level, presumably independent on the expression of embryonic genome. 본 연구는 생쥐 배아의 2세포기 분열과정중 단백질 합성양상과 단백질합성에 미치는 colcemid와 $\alpha$-amanitin의 영향을 조사하였다 이를 위하여 체내 수정된 ICR strain의 2세포기 배아와 매우 일치된 초기배아 분열양상을 보여주는 체외 수정된 F1 (C57BL x CBA) hybrid 2세포기 배아를 사용하였다. 두 종류의 2세포기 배아에서 단백질 합성은 분열단계에 따라서 매우 일치된 변화를 보여 주었다. 또한 유사분열 억제제인 colcemid (0.1mg/ml)의 처리는 2세포기 배아분열을 억제하였으나, 단백질 합성에는 아무런 변화를 주지 못하였다. 그리고 후기 2세포기 배아에 전사 억제제인 a-amanitin (100mg/ml)을 처리하였을 때 세포분열이나 다른 단백질의 합성에는 아무런 영향이 없이 단지 두개의 단백질의 합성만을 유도하였다. 이는 아마도 a-amanitin의 stress효과에 기인하는 것으로 추측된다. 따라서 생쥐 2세포기 배아의 분열과정은 배아게놈의 유전자 발현과는 무관하게 이미 합성되어 존재하는 mRNA에 의하여 조절되는 것으로 사료된다.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.2
• /
• pp.196-200
• /
• 1999

A recombinant human $\alpha_{s1}$-casein was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Three different leader sequences derived from the mating factor $\alpha$l (MF$\alpha$l), inulinase, and human $\alpha_{s1}$-casein were used to direct the secretion of human $\alpha_{s1}$-casein into the extracellular medium. Among the three leader sequences tested, the native leader sequence of human $\alpha_{s1}$-casein was found to be the most efficient in the secretory expression of human $\alpha_{s1}$-casein, which implies that the native leader sequence of human $\alpha_{s1}$-casein might be used very efficiently for the secretory production of other heterologous proteins in yeast. The recombinant human $\alpha_{s1}$-casein was proteolytically cleaved as the culture proceeded. Therefore, an attempt was made to produce human $\alpha_{s1}$-casein using a S. cerevisiae mutant in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 72 h of culture, most of the human $\alpha_{s1}$-casein secreted by the wild type was cleaved, whereas more than 70% of the human $\alpha_{s1}$-casein secreted by yap3-disruptant remained intact. The results suggest that YAP3 might be involved in the internal cleavage of human $\alpha_{s1}$-casein expressed in yeast

• The Journal of the Petrological Society of Korea
• /
• v.26 no.1
• /
• pp.45-54
• /
• 2017

The characteristics of the rock cleavage in Jurassic Geochang granite were analysed using the distribution of microcrack lengths and spacings. The phases of distribution of the above lengths and spacings were derived from the enlarged photomicrographs(${\times}6.7$) of the thin section. First, the length and spacing-cumulative diagrams for the six directions of rock cleavages were arranged in increasing order($H2{\rightarrow}R1$) on the density(${\rho}$) of microcrack length. The various parameters were extracted through the combination of the above two types of diagrams. The discrimination factors representing the three quarrying planes and three rock cleavages were acquired through the mutual contrast between the values of parameters. The analysis results of the research are summarized as follows. The evaluation for the six directions of rock cleavages was performed using the parameters such as (1) intersection angle(${\alpha}-{\beta}$) and (2) exponent difference(${\lambda}_S-{\lambda}_L$) between two exponential straight lines related to spacing(${\alpha}$, ${\lambda}_S$) and length(${\beta}$, ${\lambda}_L$). The values of parameters(1 and 2) are in order of H(hardway, (H1 + H2)/2) < G(grain, (G1 + G2)/2) < R(rift, (R1 + R2)/2). On the contrary, the values of the above two parameters for three planes are in order of R < G < H. Meanwhile, the direction of convergence between two exponential straight lines was derived. The above direction is compliant to arrangement of the line os' centering around the line ol. The above two lines converge in the direction of the Y-axis when the line ol and line os' occupy the upper region on the left and the lower region on the right, respectively(R-type). On the contrary, the above two lines converge in the direction of the X-axis when the order of arrangement between line ol and line os' is reversed(H-type). Especially, the positive(+) or negative(-) value of intersection angle(${\alpha}-{\beta}$) is determined by the arrangement of two vertical lines. This type of correlation analysis is useful for evaluating the relative strength of rock cleavage and discriminating three quarrying planes.

• Molecules and Cells
• /
• v.27 no.6
• /
• pp.651-656
• /
• 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.

• Bulletin of the Korean Chemical Society
• /
• v.11 no.1
• /
• pp.49-54
• /
• 1990

The gas-phase thermolysis reactions of ${\alpha}$- and ${\beta}$-methylated ethyl formates, Y = $CH-X-CHR_1CH_2R_2$ where X = Y = O or S and $R_1\;=\;R_2$ = H or $CH_3$, are investigated theoretically using the AM1 method. The experimental reactivity order is reproduced correctly by AM1 in all cases. The thermolysis proceeds through a six-membered cyclic transition state conforming to a retro-ene reaction, which can be conveniently interpreted using the frontier orbital theory of three-species interactions. The methyl group substituted at $C_{\alpha}\;or\;C_{\beta}$ is shown to elevate the ${\pi}$-HOMO of the donor fragment (Y = C) and depress the ${\sigma}^{\ast}$-LUMO of the acceptor fragment ($C_{\beta}$-H), increasing the nucleophilicity of Y toward ${\beta}$-hydrogen which in turn increases the reactivity. The two bond breaking processes of the $C_{\alpha}$-X and $C_{\beta}$-H bonds are concerted but not synchronous so that the reaction takes place in two stages as Taylor suggested. The initial cleavage of $C_{\alpha}$-X is of little importance but the subsequent scission of $C_{\beta}$-H occurs in a rate determining stage.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.363.1-363.1
• /
• 2002

Costunolide. a sesquiterpene lactone is isolated from Magnolia Sieboldi. It is known to possess antitumour and anti-inflammatory activities. This compound is synthesized from Ihe easily available decalin dione using the ring cleavage approach to construct the ten-membered ring system. The two keys points in this work are the chiral inductionon the allyl alcohol moiety using Sharpless epoxidation reaction and opening of the eopxide with an organocuprate reagent which leads to a $\alpha$-exomethylene lactone. (omitted)

• Journal of Oriental Neuropsychiatry
• /
• v.12 no.2
• /
• pp.157-171
• /
• 2001

Astrocytes are glial cells that play a major role in the inflammation observed in Alzheimer's disease (AD). Upon stimulation from various agents, these cells adopt a reactive phenotype, a morphological hallmark in AD pathology, during which they themselves may produce still more inflammatory cytokines. Substance P (SP) can stimulate secretion of tumor necrosis $factor-\;{\alpha}$ $(TNF-\;{\alpha})$ from astrocytes stimulated with lipopolysaccharide (LPS). Here I report that Sunghyangjungkisan- ga- pogokyoung(Sgp) can modulate cytokines secretion from primary cultures of rat astrocytes. Sgp $(10\;to\;1000\;{\mu}g/ml)$ significantly inhibited the $TNF-\;{\alpha}$ secretion by astrocytes stimulated with LPS and SP. Interleukin-1 (IL-1) has been shown to elevate $TNF-\;{\alpha}$ secretion from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. Treatment of Sgp $(10\;to\;1000\;{\mu}g/ml)$ to astrocytes stimulated with both LPS and SP decreased IL-1 secretion significantly. The secretion of $TNF-\;{\alpha}$ by LPS and SP in astrocytes was progressively inhibited with increasing amount of IL-1 neutralizing antibody. Neurodegenerative processes in AD are thought to be driven in part by the deposition of ${\beta}\;-amyloid\;(A\;{\beta})$, a 39- to 43-amino acid peptide product resulting from an alternative cleavage of amyloid precursor protein. Sgp $(10\;to\;1000\;{\mu}g/ml)$ significantly inhibited the $TNF-\;{\alpha}$ secretion by astrocytes stimulated with $A-{\beta}-$and IL-1. These results suggest that Sgp may inhibit $TNF-\;{\alpha}$ secretion by inhibiting IL-1 secretion and that Sgp has an antiinflammatory activity in AD brain

• Biomedical Science Letters
• /
• v.21 no.2
• /
• pp.126-130
• /
• 2015

There are several studies that show hypothermia improves cellular ischemia damages on experimental and clinical bases. However, its exact molecular mechanisms are unclear. In this study, we demonstrate that hypothermia induced insulin-like growth factor 1 (IGF1) gene expression, and its expression was dramatically decreased under ischemic insults. It was also demonstrated that hypothermia activated endoplasmic reticulum (ER) stress sensors especially both the phosphorylation of $eIF2{\alpha}$ (eukaryotic translation initiation factor 2 alpha) and ATF6 (activating transcription factor-6) proteolytic cleavage. However, the factors of apoptosis and autophagy were not associated with hypothermia. We suggest that hypothermia-treated IGF1 gene expression after ischemia may show a good possibility for the development of treatments and diagnostic methods in cerebral ischemic damages.

• BMB Reports
• /
• v.38 no.2
• /
• pp.248-252
• /
• 2005

Dihydrolipoamide dehydrogenase (E3) catalyzes the reoxidation of dihydrolipoyl moiety of the acyltransferase components of three $\alpha$-keto acid dehydrogenase complexes and of the hydrogen-carrier protein of the glycine cleavage system. His-457 of Pseudomonas putida E3 is suggested to interact with the hydroxyl group of Tyr-18 of the other subunit and with Glu-446, a component in the last helical structure. To examine the importance of the suggested interactions in human E3 function, the corresponding residue of human E3, Asn-473, was substituted to Leu using site-directed mutagenesis. The E3 mutant was expressed in Escherichia coli and highly purified using an affinity column. Its E3 activity was decreased about 37-fold, indicating that Asn-473 residue was important to the efficient catalytic function of human E3. Its slightly altered spectroscopic properties implied that small conformational changes could occur in the E3 mutant.

• BMB Reports
• /
• v.39 no.2
• /
• pp.223-227
• /
• 2006

Dihydrolipoamide dehydrogenase (E3) belongs to the pyridine nucleotide-disulfide oxidoreductase family including glutathione reductase and thioredoxin reductase. It catalyzes the reoxidation of dihydrolipoyl moiety of the acyltransferase components of three $\alpha$-keto acid dehydrogenase complexes and of the hydrogen-carrier protein of the glycine cleavage system. Isoleucine-51 of human E3, located near the active disulfide center Cys residues, is highly conserved in most E3s from several sources. To examine the importance of this highly conserved Ile-51 in human E3 function, it was substituted with Ala using site-directed mutagenesis. The mutant was expressed in Escherichia coli and highly purified using an affinity column. Its E3 activity was decreased about 100-fold, indicating that the conservation of the Ile-51 residue in human E3 was very important to the efficient catalytic function of the enzyme. Its altered spectroscopic properties implied that conformational changes could occur in the mutant.