• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1275-1281
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• 2005

The $G_{q/11}$ protein-coupled receptors, such as muscarinic (M1 & M3) receptors, have been shown to regulate the release of a soluble amyloid precursor protein (sAPP$\alpha$) produced from $\alpha$-secretase processing. However, there is no direct evidence for the precise characteristics of G proteins, and the signaling mechanism for the regulation of $G_{q/11}$ protein-coupled receptor mediated sAPP$\alpha$ release is not clearly understood. This study examined whether the muscarinic receptor-mediated release of sAPP$\alpha$ is directly regulated by $G\alpha_{q/11}$ proteins. The HEK293 cells were transiently cotransfected with muscarinic M3 receptors and a dominant-negative minigene construct of the G protein $\alpha$ subunit. The sAPP$\alpha$ release in the media was measured using an antibody specific for sAPP. The sAPP$\alpha$ release enhancement induced by muscarinic receptor stimulation was decreased by a $G_{q/11}$ minigene construct, whereas it was not blocked by a control minigene construct (the G$\alpha$ carboxy peptide in random order, G$\alpha_{q}$R) or $G\alpha_{j}$ constructs. This indicated a direct role of the $G\alpha_{q/11}$ protein in the regulation of muscarinic M3 receptor-mediated sAPP$\alpha$ release. We also investigated whether the transactivation of the epidermal growth factor receptor (EGFR) by a muscarinic agonist could regulate the sAPP$\alpha$ release in SH-SY5Y cells. Pretreatment of a specific EGFR kinase inhibitor, tyrophostin AG1478 (250 nM), blocked the EGF-stimulated sAPP$\alpha$ release, but did not block the oxoM­stimulated sAPP$\alpha$ release. This demonstrated that the transactivation of the EGFR by muscarinic receptor activation was not involved in the muscarinic receptor-mediated sAPP$\alpha$ release.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.507-513
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• 1996

Three sesquiterpene lactone compounds, two novel(1.betha.,3.betha.-dihydroxy-6.betha.,11.betha.,4.alpha.,5.alpha.,7.alpha.H -eudesm-12, 6-olide-1-O-.betha.-D-glucopyranoside, 1.betha.,3.betha.-dihydroxy-6.betha.,11.betha.,4.alpha.,5.alpha.,7.alpha.H-eudes m-12,6-olide-1-O-.betha.-D-glucopyranoside) and 1.betha.,3.betha.-dihydroxy-6.betha.,11.betha.,4.alpha.,5.alpha., 7.alpha.H-eudesm-12,6-olide were isolated from the aqueous fraction of MeOH extract of the roots from Taraxacum hallaisanensis (Compositae) employing Amberlite XAD-2, ODS-gel, silica gel and Sephadex LH-20 column chromatographics. Another known compound, (-)-epicatechin, was isolated from the aqueous fraction of the MeOH extract. The total MeOH extract also contained phytosterol and a mixture of .betha.-amyrin acetate, .alpha.-amyrin acetate and lupeol acetate. Structures of isolated compounds were elucidated by spectroscopic parameters of IR, Mass, /sup 13/C-NMR, /sup 1/H-NMR, /sup 1/H-/sup 1/H COSY, /sup 13/C-/sup 1/H COSY and HMBC.

• Fisheries and Aquatic Sciences
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• v.4 no.2
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• pp.70-74
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• 2001

To examine the production of steroids with potential oocyte maturation-inducing activity in the spotted flounder, Verasper variegatus, we have incubated post-vitellogenic oocytes (0.82­0.95mm in diameters) with radiolabeled pregnenolone and $17\alpha-hydroxyprogesterone$. The resulting metabolites were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The two main metabolites (progestogens) found in both incubations co-migrated with $17\alpha-hydroxy$, $20\alpha-dihydroprogesterone$ $(17\alpha, 20\alpha OHP)$ and $17\alpha-hydroxy,\;$20\beta-dihydroprogesterone$ (17 a20{30HP). Additional chromatography by HPLC and TLC confirmed the presence of radioactive $17\alpha, 20\alpha OHP$ and a large amount of unknown metabolite. The present study did not reveal in vitro formation of $l7\alpha 20\beta OHP$. Although 1$l7\alpha 20\beta OHP$ was found in a small amount, the synthesis of this steroid suggests that it may play a role in regulating the oocyte maturation process in the spotted flounder.

• Journal of the Korean Ceramic Society
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• v.25 no.5
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• pp.502-508
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• 1988

The $\alpha$ to $\beta$ phase transformation of $\alpha$-Si3N4 whisker and related microstructural changes have been investigated. When only $\alpha$-Si3N4 whisker was heat treated in the range 1650~175$0^{\circ}C$, the $\alpha$ to $\beta$ phase transformation occured. In this case, it eas suggested that the oxygen content in $\alpha$-Si3N4 whisker affected the transformation behavior. Although $\alpha$-Si3N4 whisker with Si was heat treated under the same condition, however, the variation of $\beta$- fraction had a similar tendency with heat treating time. Therfore, it was considered that the oxygen content in $\alpha$-Si3N4 whisker affected the transformation behavior dominently rather than the content of added Si. The added $\beta$ phase did not affect the transformation behaviro of $\alpha$-Si3N4 whisker.

• East Asian mathematical journal
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• v.24 no.4
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• pp.317-328
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• 2008

In this paper we introduce ${\pi}G{\alpha}$-LC sets, ${\pi}G{\alpha}-LC^*$ sets and ${\pi}G{\alpha}-LC^{**}$ sets and different notions of generalizations of continuous functions in topological space and discuss some of their properties. Further we prove pasting lemma for ${\pi}G{\alpha}-LC^{**}$ continuous functions and ${\pi}G{\alpha}-LC^{**}$ irresolute functions.

• YAKHAK HOEJI
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• v.37 no.1
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• pp.49-53
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• 1993

Arylalkanoic acid derivatives are known as good non-steroidal antiinflamatory and antirheumatic agents. The new arylalkanoic acid derivatives were synthesized when 2-chloro-3-($\alpha$-cyano-$\alpha$-ethoxycarbonyl-methyl)-1, 4-naphthoquinone was reacted with some arylamines.

• Applied Biological Chemistry
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• v.36 no.3
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• pp.191-196
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• 1993

This method using the synthesis substrate of $5-bromo-4-chloro-3-indolyl-{\alpha}-galactoside\;(X-{\alpha}-Gal)$ was examined for the differential enumeration of Bifidobacteria and lactic acid-producing bacteria. Bifidobacteria possess a high level of ${\alpha}-galactosidase$ activity. Bifidobacterium longum KCTC 3215 exhibited the highest ${\alpha}-galactosidase$ specific activity (8.57 units/mg protein). Determination of ${\alpha}-galactosidase$ activity using the PNPG procedure showed that Lactobacillus, Streptococcus, Pediococcus, and Leuconostoc strain had lower ${\alpha}-galactosidase$ activity as compared to Bifidobacteria. The $X-{\alpha}-Gal$ based medium is useful to identify Bifidobacteria among lactic acid-producing bacteria since the enzyme action of ${\alpha}-galactosidase$ spills $X-{\alpha}-Gal$ substrate and releases indol which impacts a blue color to Bifidobacterial colonies on agar plates. All strains of Bifidobacteria appeared as blue colonies on MRS agar medium supplemented with $100\;{\mu}M\;X-{\alpha}-Gal$ while colonies of other lactic acid-producing bacteria appeared white or light blue.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.37-41
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• 1995

The effect of age on the metabolism of progesterone was studied in the rat brain. Metabolic activity was more active in minced tissues than total homogenates. The activity of progesterone $5{\alpha}-reductase(s)$ was increased during postnatal periods(between 5 and 14 days after birth) and thereafter steadily decreased up to the one-fourth level of the fetus. When $5{\alpha}-dihydroprogesterone$ was incubated with brain tissues of various ages, the change in the activity of $3{\alpha}-hydroxysteroid$ oxidoreductase$(3{\alpha}-HSOR)$ was similar to that of $5{\alpha}-reductase(s)$. These results suggest that the reduced formation of total $5{\alpha}-reduced$metabolites was due to the decreased activities of $5{\alpha}-reductase(s)$ and $3{\alpha}-HSOR$. However the level of $3{\beta}-HSOR$ remained constant regardless of the age.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.802-804
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• 1990

A new colorimetric method to analyze ${\alpha}-Cyclodextrin({\alpha}-CD)$ by using a property of ${\alpha}-CD$ to decolor the starch-iodine complex, was presented. ${\alpha}-CD$ was quantitatively determined as follows. The ${\alpha}-CD$ standard solutions at concentrations up to 2 mg/ml were prepared. To 1ml of starch-iodine complex solution which contained starch(1%) and iodine (0.02% $I_2$, 0.2% KI) equivalently in distilled water, $200\;{\mu}l$ of ${\alpha}-CD$ standard solutions and 3 ml of distilled water were added and the absorbance was measured at 570 nm. Using this mothod ${\alpha}-CD$ concentration range at $0{\sim}2\;mg/ml$ could be determined and their absorbance patterns at 570 nm showed a good linearity. ${\beta}(CD)$ and glucose had no interference in this method for ${\alpha}-CD$ determination.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.332-338
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• 2002

A strain YB-4 producing the extracellular $\alpha$-galactosidase was isolated from soil, and has been identified as Streptomyces sp. on the basis of its cultural, morphological and physiological properties. The partially purified $\alpha$-galactosidase was most active on paranitrophenyl-$\alpha$-D-galactopyranoside at pH 6.0 and 6$0^{\circ}C$. The enzyme retained 90% of its maximum activity between pH 4.0 and pH 10.0 after pre-incubation for 1 h. The enzyme was able to hydrolyze oligomeric substrates such as melibiose, raffinose and stachyose to liberate galactose residue, indicating that the $\alpha$-galactosidase of Steptomyces sp. YB-4 hydrolyzed $\alpha$-1,6 linkage.