• Biomolecules & Therapeutics
• /
• v.22 no.3
• /
• pp.193-199
• /
• 2014

The aim of this study was to determine whether britanin, isolated from the flowers of Inula japonica (Inulae Flos), modulates the generation of allergic inflammatory mediators in activated mast cells. To understand the biological activity of britanin, the authors investigated its effects on the generation of prostaglandin $D_2$ ($PGD_2$), leukotriene $C_4$ ($LTC_4$), and degranulation in IgE/Ag-induced bone marrow-derived mast cells (BMMCs). Britanin dose dependently inhibited degranulation and the generations of $PGD_2$ and $LTC_4$ in BMMCs. Biochemical analyses of IgE/Ag-mediated signaling pathways demonstrated that britanin suppressed the phosphorylation of Syk kinase and multiple downstream signaling processes, including phospholipase $C{\gamma}1$ ($PLC{\gamma}1$)-mediated calcium influx, the activation of mitogen-activated protein kinases (MAPKs; extracellular signal-regulated kinase 1/2, c-Jun $NH_2$-terminal kinase and p38), and the nuclear factor-${\kappa}B$ ($NF-{\kappa}B$) pathway. Taken together, the findings of this study suggest britanin suppresses degranulation and eicosanoid generation by inhibiting the Syk-dependent pathway and britanin might be useful for the treatment of allergic inflammatory diseases.

• Journal of Plant Biotechnology
• /
• v.30 no.4
• /
• pp.411-419
• /
• 2003

The potent biosynthetic precursors, 24$\alpha$-methylcholesterol and 24$\alpha$-methylcholestanol, and the endogenous brassinosteroids (BRs), castasterone (CS) and 6-deoxocastasterone (6-deoxoCS), were identified from shoots of maize seedlings. In addition, the presence for activities of several enzymes involved in the late C6-oxida-lion pathway from 24$\alpha$-methylcholestanol to CS was demonstrated in the plants. However, activity for brassinolide (BL) synthase which catalyze the conversion of CS to BL, the last step of the late C6-oxidation pathway, was not detected in the enzyme solution obtained from the maize shoots. Together with the fact that BL was not identified from the maize shoots, these results strongly suggested that BRs in the maize shoots are biosynthesized during seedling growth and the active BR in the shoots is not BL but CS.

• Food Science and Biotechnology
• /
• v.17 no.2
• /
• pp.367-372
• /
• 2008

Cellular protection against carcinogens could be achieved by the induction of phase 2 detoxifying and antioxidant enzymes such as glutathione S-transferase (GST), NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO1). Nuclear transcription factor E2-related factor 2 (Nrf2) binds to antioxidant response element (ARE) in the promoter region of these genes and the resulting transactivation occurs. In the present study the effect of gujeolcho (Chrysanthemum zawadskii) roots on the Nrf2-ARE pathway were investigated. C. zawadskii root extract was fractionated with a series of organic solvents and their ability to induce Nrf2-ARE pathway was examined. We separated the most potent dichloromethane (DCM) fraction into 12 sub-fractions and found several sub-fractions with strong effects on the Nrf2-ARE pathway. Fraction 4 strongly induced the ARE-reporter gene activity as well as Nrf2 expression. Sitosterol was isolated as a major compound in fraction 4 although its activity was not as potent as its mother fraction. These results indicate that C. zawadskii roots might be used as a potential natural chemopreventive source.

• Biomolecules & Therapeutics
• /
• v.26 no.3
• /
• pp.313-321
• /
• 2018

Anti-cancer drug resistance is a major problem in colorectal cancer (CRC) research. Although several studies have revealed the mechanism of cancer drug resistance, molecular targets for chemotherapeutic combinations remain elusive. To address this issue, we focused on the expression of cellular prion protein ($PrP^C$) in 5-FU-resistant CRC cells. In 5-FU-resistant CRC cells, $PrP^C$ expression is significantly increased, compared with that in normal CRC cells. In the presence of 5-FU, $PrP^C$ increased CRC cell survival and proliferation by maintaining the activation of the PI3K-Akt signaling pathway and the expression of cell cycle-associated proteins, including cyclin E, CDK2, cyclin D1, and CDK4. In addition, $PrP^C$ inhibited the activation of the stress-associated proteins p38, JNK, and p53. Moreover, after treatment of 5-FU-resistant CRC cells with 5-FU, silencing of $PrP^C$ triggered apoptosis via the activation of caspase-3. These results indicate that $PrP^C$ plays a key role in CRC drug resistance. The novel strategy of combining chemotherapy with $PrP^C$ targeting may yield efficacious treatments of colorectal cancer.

• Proceedings of the Ginseng society Conference
• /
• 2002.10a
• /
• pp.66-83
• /
• 2002

Recently, we have provided evidence that ginsenosides, the active components of Panax ginseng, utilize pertussis toxin (PTX)-insensitive $G{\alpha}_{q/11}-phospholipase\;C-{\beta}3(PLC-{\beta}3)$ signal transduction pathway for the enhancement of $Ca^{2+}-activated\;Cl^{-}$ current in the Xenopus oocyte (British J. Pharmacol. 132, 641-647, 2001; JBC 276, 48797-48802, 2001). Other investigators have shown that stimulation of receptors linked to $G{\alpha}-PLC$ pathway inhibits the activity of G proteincoupled inwardly rectifying $K^+$ (GIRK) channel. In the present study, we sought to determine whether ginsenosides influenced the activity of GIRK 1 and GIRK 4 (GIRK 1/4) channels expressed in the Xenopus oocyte, and if so, the underlying signal transduction mechanism. In oocyte injected with GIRK 1/4 channel cRNAs, bath-applied ginsenosides inhibited high potassium (HK) solution-elicited GIRK current $(EC_{50}:4.9{\pm}4.3\;{\mu}g/ml).$ Pretreatment of the oocyte with PTX reduced the HK solution-elicited GIRK current by $49\%,$ but it did not alter the inhibitory ginsenoside effect on GIRK current. Prior intraoocyte injection of cRNA(s) coding $G{\alpha}_q,\;G{\alpha}_{11}\;or\;G{\alpha}_q/G{\alpha}_{11},\;but\;not\;G{\alpha}_{i2}\;or\;G{\alpha}_{oA}$ attenuated the inhibitory ginsenoside effect. Injection of cRNAs coding $G{\beta}_{1{\gamma}2}$ also attenuated the ginsenoside effect. Similarly, injection of the cRNAs coding regulators of G protein signaling 1, 2 and 4 (RGS1, RGS2 and RGS4), which interact with $G{\alpha}_i\;and/or\;G{\alpha}_{q/11}$ and stimulates the hydrolysis of GTP to GDP in active GTP-bound $G{\alpha}$ subunit, resulted in a significant reduction of ginsenoside effect on GIRK current. Preincubation of GIRK channel-expressing oocyte in PLC inhibitor (U73122) or protein kinase C (PKC) inhibitor (staurosporine or chelerythrine) blocked the inhibitory ginsenoside effect on GIRK current. On the other hand, intraoocyte injection of BAPTA, a free $Ca^{2+}$ chelator, had no significant effect on the ginsenoside action. Taken together, these results suggest that ginsenosides inhibit the activity of GIRK 1/4 channel expressed in the Xenopus oocyte through a PTX-insensitive and $G{\alpha}_{q/11}$-,PLC-and PKC-mediated signal transduction pathway.

• Mycobiology
• /
• v.46 no.4
• /
• pp.407-415
• /
• 2018

Pheromone (PHB)-receptor (RCB) interaction in the mating pheromone response pathway of Lentinula edodes was investigated using synthetic PHBs. Functionality of the C-terminally carboxymethylated synthetic PHBs was demonstrated by concentration-dependent induction of a mating-related gene (znf2) expression and by pseudoclamp formation in a monokaryotic strain S1-11 of L. edodes. Treatment with synthetic PHBs activated the expression of homeodomain genes (HDs) residing in the A mating type locus, and of A-regulated genes, including znf2, clp1, and priA, as well as genes in the B mating type locus, including pheromone (phb) and receptor (rcb) genes. The synthetic PHBs failed to discriminate self from non-self RCBs. PHBs of the B4 mating type (B4 PHBs) were able to activate the mating pheromone response pathway in both monokaryotic S1-11 and S1-13 strains, whose B mating types were B4 (self) and B12 (non-self), respectively. The same was true for B12 PHBs in the B4 (non-self) and B12 (self) mating types. The synthetic PHBs also promoted the mating of two monokaryotic strains carrying B4-common incompatible mating types ($A5B4{\times}A1B4$). However, the dikaryon generated by this process exhibited abnormally high content of hyphal branching and frequent clamp connections and, more importantly, was found to be genetically unstable due to overexpression of mating-related genes such as clp1. Although synthetic PHBs were unable to discriminate self from non-self RCBs, they showed a higher affinity for non-self RCBs, through which the mating pheromone response pathway in non-self cells may be preferentially activated.

• Applied Biological Chemistry
• /
• v.35 no.3
• /
• pp.210-217
• /
• 1992

A photosynthetic bacterium strain KUP-74 producing high amount of S-amino-levulinic acid(ALA) was isolated from soils, which was identified as Rhodocyclus gelatinosus. After 10 days cultivation under anaerobic-light condition at $30^{\circ}C$, 4 Klux and pH 6.8, 5 mg/l of ALA was formed extracellularly. ALA productions were increased up to 8 mg/l and 12 mg/l in cell cultivations either by the addition of 0.5% glycerol (v/v) or 10 mM of glycine and succinic acid, respectively, using Lascelles basal medium eliminated L-glutamic acid. By cultivation in the presence of 30 mM each D,L-glutamic acids and D,L-glutamines the yield of ALA showing a late induction phenomenon was reached the maximum value of 21 mg/l. Different culture times were needed to generate maximum ALA yields by the addition of initial precursors of $C_4$ and $C_5$ pathways in basal medium, as being 107 h and 262 h, respectively. 40 mg/l yield of ALA was observed by cell cultivation with the basal medium containing each 10 mM levulinic acid(LA) and glycine simultaneously.

• Korean Journal of Food Science and Technology
• /
• v.34 no.2
• /
• pp.290-295
• /
• 2002

Among 12 lactic acid bacteria examined for their abilities to activate the complement system by hemolytic complement assay $(TCH_{50})$, Lactobacillus plantarum previously isolated from Kimchi showed high anti-complementary activity. The anti-complementary activity of the cell wall fraction of L. plantarum was more potent than that of the cytosol fraction, and both activities showed dose dependency. These high activities of the cytosol and the cell wall fractions were relatively resistant to the digestion with pronase, but sharply decreased after the treatment of $NaIO_4$. These results suggested that the complement activation by the cytosol and the cell wall fractions was mainly due to their polysaccharides. By the cross-immunoelectrophoresis using anti-human C3, the C3 activation products from both fractions were identified in $Ca^{++}$-free condition. Anti-complementary activity $(ITCH_{50})$ of the cell wall fraction was retained under the same condition, whereas that of the cytosol fraction was reduced considerably. From these results, it was inferred that the mode of complement activation by the cell wall fraction was mainly via alternative pathway, and that of the cytosol fraction was via both alternative and classical pathways.

• Korean Journal of Microbiology
• /
• v.31 no.4
• /
• pp.261-266
• /
• 1993

A new methyltrophic bacterium which utilizes methanol as a sole source of carbon and energy was isolated from soil. It was Gram-negative, nonmotile, nonspore-forming rod, and strictly aerobic bacterium. Catalase and oxidase activities were present. Nitrate was reduced to nitrite. Vitamins and other growth factors were not required. Generation time was 1.6 hr under the optimal condition. The isolate assimilated methanol via the ribulose mono-phosphate pathway (Enter-Doudoroff varient) and did not have .alpha.-ketoglutarate dehydrogenase. It assimilated ammonia through glutamate dehydrogenase. The guanine plus cytosine content of the DNA was 61.0 mol%. The celular fatty acid composition was primarily straight-chain saturated $C^{16 : 0}$ acids (palmitic acids) and unsaturated $C_{16 :1}$ acid (palmitoleic acids), and the isolate also contained two unidentified $C_{17}$ branched fatty acids. The major ubiquinone was Q-8, and Q-6 and Q-7 were present as minor components. Phosphatidylethanolamine and phosphatidylglycerol were predominantly present, and diphosphatidyglycerol was also detected. Based on the physiological and biochemical properties, the isolate was assigned to a novel species of the genus Methylobacillus, Methylobacillus methanolovorus sp. nov.

• The Korean Journal of Ecology
• /
• v.13 no.4
• /
• pp.331-342
• /
• 1990

Analysis of vegetation on the pavements and under the trees of streets in Seoul city were investigated from July to November 1989. All of the vascular herbs were 9 orders, 13 families, 30 genera, 37 species and 1 forma. Species diversity and evenness index were higher on the pavements than under the trees of streets. Eragrostis multicaulis with C-4 pathway was a dominant species, and next orders of importace values were Eleusine indica(C-4), Digitaria sanguinalis(C-4), Taraxacum officinale(C-3) and Erigeron annus(C-3). On the pavements and under the trees of streets, light intensity and surface temperature were very high, Also, these sites were affected by many kinds of human interferences. Therefore, it was an example of adaptation to specific ecological environments that C-4 plats were more dominant than C-3, growth forms of C-3 plants were rosette or prostrate, and annual or biennial plants were distributed in these studied sites. Generally, fruits types were grains, achens and capsules. Seeds were very small and some had appendages such as pappus.