• Biomolecules & Therapeutics
• /
• v.10 no.4
• /
• pp.293-302
• /
• 2002

The classical concept for iron uptake into mammalian cells has been the endocytosis of transferrin( $T_{f}$ )-bound F $e^{3+}$ via the $T_{f}$ - $T_{f}$ receptor cycle. In this case, we could not explain the uptake of F $e^{2＋}$ ion and the export of iron from endosome. Studies on iron transport revealed that other transport system exists in epithelial cells of the intestine. One of non- $T_{f}$ -receptor-mediated transport systems is Nramp2/DMT1/DCT1 which transports M $n^{＋＋}$, $Mg^{＋＋}$, Z $n^{＋＋}$, $Co^{＋＋}$, N $i^{＋＋}$ or C $u^{＋＋}$ ion as well as F $e^{+2}$ ion. DMT1 was cloned from intestines of iron-deficient rats and shown to be a hydrogen ion-coupled iron transporter and a protein regulated by absorbed dietary iron. DMT1 is founded in other cells such as cortical and hippocampal glial cells as well as endothelial cells in duodenum. Two F $e^{3+}$ ion bound to transferrin( $T_{f}$ ) are taken up via the $T_{f}$ - $T_{f}$ receptor cycle in the intestinal epithelial cell. F $e^{3+}$ in endosome was converted to F $e^{2＋}$ ion, and then exported to cytosol via DMT1. F $e^{2＋}$ ion is taken up into cytosol via DMT1. Several other transporters such as FET, FRE, CCC2, AFT1, SMF, FTR, ZER, ZIP, ZnT and CTR have been reported recently and dysfunction of the transporters are related with diseases containing Wilson's disease, Menkes disease and hemochromatosis. Evidences from several studies strongly suggest that DMT1 is the major transporter of iron in the intestine and functions critically in transport of other metal ions.

• Microbiology and Biotechnology Letters
• /
• v.49 no.1
• /
• pp.57-64
• /
• 2021

Lactic acid bacteria (LAB), belonging to the Firmicutes phylum, lack heme biosynthesis and, thus, are characterized as fermentative and catalase-negative organisms. To verify the hypothesis that heme-rich-nutrients might compensate the heme-biosynthesis incapability of non-respiratory LAB in animal gut, a heme-rich-nutrient was fed to a dog and its fecal microbiome was analyzed. Firmicutes abundance in the feces from the heme-rich-nutrient-fed dog was 99%, compared to 92% in the control dog. To clarify the reason of increased Firmicutes abundance in the feces from the heme-rich-nutrient-fed dog, Lacobacillus gasseri were used as model anerobic LAB to study a purified heme (hemin). The anaerobic growth of L. gasseri in the medium with 25 µM hemin supplementation was faster than that in the medium without hemin, while the growth in the 50 µM hemin-supplemented medium did not vary. Cellular activities of the cytochrome bd complex were 1.55 ± 0.19, 2.11 ± 0.14, and 2.20 ± 0.08 U/gcell in the cells from 0, 25, and 50 µM hemin-supplemented medium, while intracellular ATP concentrations were 7.90 ± 1.12, 11.95 ± 0.68, and 12.56 ± 0.58 µmol_ATP/g_cell, respectively. The ROS-scavenging activities of the L. gasseri cytosol from 25 µM and 50 µM hemin-supplemented medium were 68% and 82% greater than those of the cytosol from no hemin supplemented-medium, respectively. These findings indicate that external hemin could compensate the heme-biosynthesis incapability of L. gasseri by increasing the cytosolic ROS-scavenging and extra ATP generation, possibly through increasing the electron transfer. Increase in the number of anaerobic bacteria in heme-rich-nutrient-fed animal gut is discussed based on the results.

• Biomolecules & Therapeutics
• /
• v.32 no.1
• /
• pp.56-64
• /
• 2024

Biased signaling or functional selectivity refers to the ability of an agonist or receptor to selectively activate a subset of transducers such as G protein and arrestin in the case of G protein-coupled receptors (GPCRs). Although signaling through arrestin has been reported from various GPCRs, only a few studies have examined side-by-side how it differs from signaling via G protein. In this study, two signaling pathways were compared using dopamine D₂ receptor (D₂R) mutants engineered via the evolutionary tracer method to selectively transduce signals through G protein or arrestin (D₂G and D₂Arr, respectively). D₂G mediated the inhibition of cAMP production and ERK activation in the cytoplasm. D₂Arr, in contrast, mediated receptor endocytosis accompanied by arrestin ubiquitination and ERK activation in the nucleus as well as in the cytoplasm. D₂Arr-mediated ERK activation occurred in a manner dependent on arrestin3 but not arrestin2, accompanied by the nuclear translocation of arrestin3 via importin1. D₂R-mediated ERK activation, which occurred in both the cytosol and nucleus, was limited to the cytosol when cellular arrestin3 was depleted. This finding supports the results obtained with D₂Arr and D₂G. Taken together, these observations indicate that biased signal transduction pathways activate distinct downstream mechanisms and that the subcellular regions in which they occur could be different when the same effectors are involved. These findings broaden our understanding on the relation between biased receptors and the corresponding downstream signaling, which is critical for elucidating the functional roles of biased pathways.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.2
• /
• pp.116-126
• /
• 1993

The purposes of this study were to investigate the effect of seleniumc (Se) and vitamin E on activity of enzyme relevant to lipid peroxidation in alcohol administrated rats. Seventy two male rats of Sprague-Dawley strain weighing about 58~62g were divided into 12groups. The dietary Se levels were 0, 0.4 and 10mg and the dietary vitamin E levels were 0 and 150mg per kg diet, respectively. Alcohol-administrated groups received drinking water solution containing 10% of ethanol from the 3-weeks of experimental periods. The obtained experimental results are summarized as follow: The ${\gamma}$-GTP activity in plasma was higher in alcohol administrated groups and high selenium group (HSe) and low selenium group (LSe) than in control groups (CSe). The ${\gamma}$-GOT and GPT activities were higher in alcohol groups. The ${\gamma}$-GTP activity was significantly influenced by alcohol in LSe groups than in other groups. The glutathione peroxidase (GSH-Px) activity of plasma was significantly lower in LSe groups than HSe and CSe groups. The GSH-Px activity of microsomal and cytosolic fraction was slightly lower in alcohol groups and was about a half value lower in HSe and LSe groups than CSe groups. There was negative correlation between plasma Se level and GSH-Px activity of cytosolic fraction in HSe groups (r=- 0.662, p<0.001) and positive correlation in LSe groups (r=0.640, p<0.001). The GSH S-transferase activity in microsomal and cytosolic fraction was slightly higher in alcohol administrated but vitamin E nonadministrated groups, and significantly higher in LSe groups than in other groups. The catalase activity in mitochondria was lower in HSe than CSe groups, but rather higher in LSe groups. The superoxide dismutase (SOD) activity in cytosolic fraction of liver was not found any effect in all groups. The cytochrome P-450 was higher in alcohol groups, but significantly lower in HSe groups. In conclusion, the deficiency of Se and vitamin E develops the hyperoxidation of liver lipid through the increase of activity of enzyme related to the lipid peroxidation and alcohol administration appears to further increase of hyperoxidation of liver lipid.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.139-148
• /
• 2020

Red rose petals are usually disposed but they are an abundant source of phenolics and traditionally used as food supplement and as herbal medicine. Of the Various phenolics, they are known to have anticancer, antioxidant, and anti-inflammatory properties. In this study, we investigated the anti-inflammatory effects of red rose ethanolic extracts (GRP) on lipopolysaccharide (LPS)-activated RAW 264.7 cells. The results demonstrated that pretreatment of GRP (500㎍/mL) significantly reduced NO production by suppressing iNOS protein expression in LPS-stimulated cells. Anti-inflammatory effects by red rose petals were observed in the following. Red rose petals inhibited the translocation of NF-κB from the cytosol to the nucleus via the suppression of IκB-α phosphorylation and also inhibited LPS-stimulated NF-κB transcriptional activity. These findings suggest that red rose petals exert anti-inflammatory actions and help to elucidate the mechanisms underlying the potential therapeutic values of red rose petals. Therefore, red rose petals could be regarded as a potential source of natural anti-inflammatory agents.

• YAKHAK HOEJI
• /
• v.38 no.1
• /
• pp.12-19
• /
• 1994

Capsaicin(8-methyl-N-vanillyl-6-nonenamide) is the principal pungent component of Capsicum fruits. This work is directed to the capsaicin-hydrolyzing enzyme playing a key role in the rate limiting and critical step of capsaicin metabolism. In order to get precise information on the enzyme's subcellular location, rat liver homogenate was divided into six subcellular fractions by differential centrifugation technique: crude nuclear pellet, PNS(post nuclear supernatant) fraction, lysosomal pellet, cytosol, Tris wash fraction, micrisomes. Capsaicin-hydrolysing enzyme activity was analysed by high performance liquid chromatography(HPLC). This enzyme was found at the highest specific activity in the microsomal fraction and co-distributed with marker enzymes of the endoplasmic reticulum, NADPH-cytochrome c reductase and nucleoside diphosphatase. This is compatible with the result of ninhydrin color reaction of vanillylamine, primary metabolite of capsaicin hydrolysis, on thin layer chromatography(TLC). This enzyme is most active at pH $8.0{\sim}9.0$. Definite subcellular location of this enzyme will make it easy to proceed with further study.

• 대한치주과학회:학술대회논문집
• /
• 2005.11a
• /
• pp.87-88
• /
• 2005

• KSBB Journal
• /
• v.15 no.3
• /
• pp.318-322
• /
• 2000

An oxygen-sensitive fumarate reductase has been purified from the cytosol fraction of the Enterococcus faecalis RKY1 grown anaerobically on a defined medium containing glycerol and fumarate. A major portion of the purification was performed with employing Triton X-100 and reducing agents by Phenyl-sepharose CL-4B DEAE-sepharose and Dephadex G-150 The final activity was 0.42 unit/mg. The deduced molecular mass of active band was 66 kDa. The optimal pH and temperature for the activity were 7.0 and 38$^{\circ}C$ respectively. The enzyme activity was not affected by 1mM metal ions such as bacl2 $.$2H2O HgCl2 MnCl2$.$4H2O ZnCl2 CuCl2$.$2H2O Mgcl2$.$6H2O FeSo4$.$7H2O and by EDTA. Partially purified enzyme ws yellow in color ; spectroscopic study indicated the presence of flavins as a cofactor.

• BMB Reports
• /
• v.42 no.7
• /
• pp.456-461
• /
• 2009

Proteomic analyses of differentially expressed proteins in rat retinal ganglion cells (RGC-5) following S-nitrosoglutathione (GSNO), an NO donor, treatment were conducted. Of the approximately 314 protein spots that were detected, 19 were differentially expressed in response to treatment with GSNO. Of these, 14 proteins were up-regulated and 5 were down- regulated. Notably, an increase in GAPDH expression following GSNO treatment was detected in RGC-5 cells through Western blotting as well as proteomics. The increased GAPDH expression in response to GSNO treatment was accompanied by an increase in Herc6 protein, an E3 ubiquitin ligase. Moreover, GSNO treatment resulted in the translocation of GADPH from the cytosol to the nucleus and its subsequent accumulation. These results suggest that NO stress-induced apoptosis may be associated with the nuclear translocation and accumulation of GAPDH in RGC-5 cells.

• Applied Microscopy
• /
• v.21 no.2
• /
• pp.117-125
• /
• 1991

This study has been carried out to investigate the development of dictyosome, and roles of dictyosome about the formation of spherosome in the endosperm cell during seed formation of Panax ginseng with electron microscope. The result is as follows; In the endosperm cells of early stage during seed formation of Panax ginseng, plastid, mitochondria, endoplasmic reticulum, dictyosome and ribosomes are evenly distributed in cytoplasm. Electron lucent vesicles derived from dictyosome are observed in endosperm cells. Vesicles that contain low electron density are derived from forming face of dictyosome and releases into the cytosol. This vesicles formed multi vesicular body or fused with the plasma membrane. The spherical spherosomes are formed from dictyosome containing the lipid materials of even electron density and are gradually increased in size and number. Dictyosome is located in between vacuole and spherosome and it's cisternae form a semicircle and a circle. Some membrane of the protein body that accumulate the storage protein are originate from the spherical vacuole which interfused between vesicles and vacuoles derived from dictyosome.