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Park S.-Y.,Korea University | Lim J.-Y.,Korea University | Jeong W.,Korea University | Hong S.S.,Korea University | And 3 more authors.
Planta Medica | Year: 2010

Increased beta-amyloid (A) production and its aggregation to the oligomeric state is considered to be a major cause of Alzheimer's disease (AD). Therefore, reducing A-induced neurotoxicity could provide a suitable means of prevention or intervention in the disease course of AD. The neuroprotective effects of isolates from Callistemon lanceolatus DC. (Myrtaceae) against A were evaluated using PC12 cells. To evaluate the effects of A on apoptotic cell death and the effects of Bcl-2 family proteins and caspase-3, TUNEL assays and Western blotting were performed, respectively. Substantial fractionation and purification of the EtOAc-soluble extract of the aerial parts of C. lanceolatus afforded six flavonoids, 4,5-dihydroxy-6,8-dimethyl-7-methoxyflavanone (1), eucalyptin (2), 8-demethyleucalyptin (3), sideroxylin (4), syzalterin (5), and quercetin (6). Compounds 1, 5, and 6 were found to protect PC12 cells effectively against A-induced toxicity. In particular, compound 1 showed the most promising neuroprotective effect with an EDvalue of 6.7μ M in terms of decreasing A-induced apoptotic cell death, and this was accompanied by a decrease in caspase-3 activation and an increase in Bcl-2/Bax ratio. These results suggest that compound 1 could be developed as a candidate anti-AD agent due to its attenuation of A-induced apoptotic cell death. © Georg Thieme Verlag KG Stuttgart New York.

Kim J.Y.,Jeju special self governing province Agricultural Research and Extension Services | Kim J.Y.,Jeju National University | Kim Y.-K.,GreenGene BioTech Inc. | Kim Y.M.,Jeju National University | And 6 more authors.
Journal of the Korean Society for Applied Biological Chemistry | Year: 2013

Snail family proteins (Snail1 and Slug/Snail2) are transcription factors that regulate transcription of molecules during epithelial-mesenchymal transition (EMT). Snail1/2 is known to bind to the E-box motif (CANNTG). The proteasome activity is decreased in EMT (Kim et al., 2011), and several E-box motifs are found in the promoters of genes coding for proteasome subunits. We used a new protein-binding microarray to specify the Slug/Snail2 binding sequence. Among 563 9-mer clusters, the motif CACCTGC yielded the highest P-value in the Wilcoxon-Mann-Whitney test. Within this motif, the A and T were absolutely required, and CC was preferred, but could be replaced by GG with little effect. In hepatocytes overexpressing Slug/Snail2, the 20S proteasome expression and proteasome activity were decreased partly due to the down-regulation of proteasome subunit beta type 2 (PSMB2) and PSMB3 transcription. © 2013 The Korean Society for Applied Biological Chemistry.

Kim S.-B.,Jeju National University | Oh E.U.,Jeju National University | Park J.H.,Jeju National University | Yun S.-H.,Citrus Research Station | And 5 more authors.
Korean Journal of Horticultural Science and Technology | Year: 2013

The study was conducted to investigate the effect of fruit bearing type with leafy (LY) and leafless (LS) fruits on fruit growth, sugar, and acid characteristics in satsuma mandarin. Fruit growth including fruit length, diameter, shape index (diameter/length), weight, and size distribution was not different between LY and LS fruits at ripening time. Total soluble solids (TSS) concentration of the fruit juice increased and acidity decreased continuously and then TSS:acidity ratio increased with fruit development from 100 days after anthesis to ripening time. Soluble sugar was continuously increased, whereas organic acid decreased. Theses tendencies were related to the increase of sucrose and decline of citric acid, respectively. However, there was no effect of fruit bearing type on TSS, acidity, and TSS:acidity ratio, and soluble sugar and organic acid composition in fruit juice. Also, photosynthetic rate and chlorophyll index with SPAD value were not different between leaves adjacent to LY and LS fruits. The results indicated that fruit growth and sugar and acid characteristics were not affected by fruit bearing type with leafy and leafless fruits in satsuma mandarin.

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