• Journal of Plant Biology
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• v.35 no.2
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• pp.125-134
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• 1992

Taxonomic account is given to the five species of Scytosiphonaceae, Colpomenia peregrina (Sauvageau) Hamel, Endarachne binghamiae J. Agardh, Hydroclathrus clathratus (C. Agardh) Howe, Petalonia fascia (O. F. Muller) Kuntze, and Scytosiphon lomentaria (Lyngbye) Link, collected from Ullungdo Island, Korea. C. peregrina, introduced for the first time in Korea, is similar to C. sinuosa (Roth) Derbes et SolieI in outer appearance but is distinguished by absence of cuticle over the plurilocular sporangial sori. E. binghamiae accords well with American plants but varies in height and width of the thallus according to seasons. H. clathratus has small cortical cells and large clear medullary cells. P fascia is characterized by one to two celled small cortical layer and two to four celled large medullary layer. S. lomentaria shows variation in gross morphology, especially in height and width of thallus according to seasons.easons.

• Natural Product Sciences
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• v.17 no.3
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• pp.221-224
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• 2011

A $CH_3Cl$ extract from the flower of Lonicera japonica (Lauraceae) significantly protected primary cultures of rat cortical cells injured by the excitotoxic amino acid, L-glutamate. Loganin (1), secoxyloganin (2), caffeic acid (3) rutin (4), hyperoside (5), quercetin-3-O-glucoside (6), lonicerin (7), kaempferol-3-O-rutinoside (8), luteolin-7-O-b-D-glucopyranoside (9), quercetin (10) and luteolin (11) were isolated by bioactivity-guided fractionation from the $CH_3Cl$ fraction and further separated using chromatographic techniques. Caffeic acid, lonicerin, kaempferol-3-O-rutinoside, quercetin and luteolin had significant neuroprotective activities against glutamate-induced neurotoxicity in primary cultures of rat cortical cells at concentrations ranging from $0.1{\mu}M$ to $10.0\;{\mu}M$.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.427-433
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• 1998

In brain hypoxic-ischemia, an excess release of glutamate and a marked production of reactive oxygen species (ROS) occur in neuronal and non-neuronal cells. The present study investigated the effect of the biological antioxidants dihydrolipoic acid (DHLA) and lipoic acid (LA) on N-methyl-D-aspartate (NMDA)- and ROS-induced neurotoxicity in cultured rat cortical neurons. DHLA enhanced NMDA-evoked rises in intracellular calcium concentration ($[Ca^{2+}]_i$). In contrast, LA did not alter the NMDA-evoked calcium responses but decreased after a brief treatment of dithiothreitol (DTT), which possesses a strong reducing potential. Despite the modulation of NMDA receptor-mediated rises in $[Ca^{2+}]_i$, neither DHLA nor LA altered the NMDA receptor-mediated neurotoxicity, as assessed by measuring the amount of lactate dehydrogenase released from dead or injured cells. DHLA, but not LA, prevented the neurotoxicity induced by xanthine/xanthine oxidase-generated superoxide radicals. Both DHLA and LA decreased the glutathione depletion-induced neurotoxicity. The present data may indicate that biological antioxidants DHLA and LA protect neurons from ischemic injuries via scavenging oxygen free radicals rather than modulating the redox modulatory site(s) of NMDA receptor.

• Animal cells and systems
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• v.9 no.1
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• pp.19-25
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• 2005

This study was conducted to determine the effect of dietary salt on the synthesis of glucocorticoids in the adrenal cortex of mice. Mice had ad libitum access to 3% sodium chloride as the only drinking fluid (high salt diet) for either 4 days or 4 weeks. Adrenocortical expression of cytochrome P450 11beta-hydroxylase, a major regulatory enzyme in the biosynthesis of glucocorticoids, was examined by immunohistochemistry and western blot analysis. Ultrastructure of adrenocortical cell and plasma level of corticosterone were analyzed as well. Size and density of lipid droplets in the cortical cell were increased by high salt diet. Four days of high salt diet decreased P450 11beta-hydroxylase in the adrenal cortex, but 4 weeks increased it. Plasma level of corticosterone changed in parallel with the Cortical level of P450 11 beta-hydroxylase. These results suggest that high salt diet may modulate the biosynthesis of glucocorticoids, at least partly, via regulating the expression of P450 11beta-hydroxylase in adrenocortical cells.

• ALGAE
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• v.20 no.3
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• pp.225-232
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• 2005

Optical microscopy of recently living and cleared material of the fucoid, Ascophyllum nodosum (L.) Le Jolis, revealed novel aspects of its interaction with the ascomycete Mycophycias ascophylli (Cotton) Kohlmeyer and Kohlmeyer (previously Mycosphaerella ascophylli Cotton). Most host cells are associated with hyphae by lateral attachment of cell walls. Hyphae form extensive networks throughout the host thallus and show considerable differentiation in the various host tissues. In the base of epidermal cells, hyphae form multicellular rings around each host cell to produce a continuous network. In medullary regions, long, relatively unbranched and longitudinally aligned hyphae occur, with radial branches extending into cortical regions. Scattered in the inner cortex of host tissue are numerous multicellular nodes of smaller, polygonal to irregular shaped cells with five or more radiating arms of hyphae. Individual hyphal cells show a variety of specializations including swellings and appressoria-like attachments to some host cells. These observations provide the morphological basis for the mutualistic symbiosis supported by recent experimental work. We conclude that this association is best described by the term “symbiotum.”

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.3
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• pp.229-236
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• 2016

Resveratrol (RSV) may provide numerous protective effects against chronic inflammatory diseases. Due to local hypoxia and hypertonicity, the renal medulla is subject to extreme oxidative stress, and aldehyde products formed during lipid peroxidation, such as 4-hydroxy-2-hexenal (HHE), might be responsible for tubular injury. This study aimed at investigating the effects of RSV on renal and its signaling mechanisms. While HHE treatment resulted in decreased expression of Sirt1, AQP2, and nuclear factor erythroid 2-related factor 2 (Nrf2), mouse cortical collecting duct cells (M1) cells treated with HHE exhibited increased activation of p38 MAPK, extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and increased expression of NOX4, $p47^{phox}$, Kelch ECH associating protein 1 (Keap1) and COX2. HHE treatment also induced $NF-{\kappa}B$ activation by promoting $I{\kappa}B-{\alpha}$ degradation. Meanwhile, the observed increases in nuclear $NF-{\kappa}B$, NOX4, $p47^{phox}$, and COX2 expression were attenuated by treatment with Bay 117082, N-acetyl-l-cysteine (NAC), or RSV. Our findings indicate that RSV inhibits the expression of inflammatory proteins and the production of reactive oxygen species in M1 cells by inhibiting $NF-{\kappa}B$ activation.

• Biomolecules & Therapeutics
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• v.25 no.6
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• pp.593-598
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• 2017

The $Na^+/H^+$ exchanger-1 (NHE-1) is a ubiquitously expressed pH-regulatory membrane protein that functions in the brain, heart, and other organs. It is increased by intracellular acidosis through the interaction of intracellular $H^+$ with an allosteric modifier site in the transport domain. In the previous study, we reported that glutamate-induced NHE-1 phosphorylation mediated by activation of protein kinase C-${\beta}$ (PKC-${\beta}$) in cultured neuron cells via extracellular signal-regulated kinases (ERK)/p90 ribosomal s6 kinases (p90RSK) pathway results in NHE-1 activation. However, whether glutamate stimulates NHE-1 activity solely by the allosteric mechanism remains elusive. Cultured primary cortical neuronal cells were subjected to intracellular acidosis by exposure to $100{\mu}M$ glutamate or 20 mM $NH_4Cl$. After the desired duration of intracellular acidosis, the phosphorylation and activation of PKC-${\beta}$, ERK1/2 and p90RSK were determined by Western blotting. We investigated whether the duration of intracellular acidosis is controlled by glutamate exposure time. The NHE-1 activation increased while intracellular acidosis sustained for >3 min. To determine if sustained intracellular acidosis induced NHE-1 phosphorylation, we examined phosphorylation of NHE-1 induced by intracellular acidosis by transient exposure to $NH_4Cl$. Sustained intracellular acidosis led to activation and phosphorylation of NHE-1. In addition, sustained intracellular acidosis also activated the PKC-${\beta}$, ERK1/2, and p90RSK in neuronal cells. We conclude that glutamate stimulates NHE-1 activity through sustained intracellular acidosis, which mediates NHE-1 phosphorylation regulated by PKC-${\beta}$/ERK1/2/p90RSK pathway in neuronal cells.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.285-296
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• 1995

Anatomical studies of sink tissues are required for better understanding the biological plant growth system and energy metabolism. Kinematics of root growth zones of two genotypes of tall fescue (Festuca arundinacea Schreb.) receiving 50 or 200 ppm N were determined. Longitudinal anatomy and cell dynamics of root growth zones were studied and calculated. The root growth zone is organized similarly to the leaf growth zone which has cell division, elongation, and maturation zones, but the root growth zone is only about 3.0 mm long compared to 25 to 30 mm for the leaf growth zone. The root cap extends about 0.4 to 0.5 mm from the apical initial, while the cell elongation zone for both cortical and metaxylem cells extends about 3.3 mm from the apical initial for both genotypes and N levels. Root cap cells elongate from an initial length of about 5$\mu{m}$ long to a final length of about 40$\mu{m}$ before being sloughed. Initial lengths of cortical and metaxylem cells were about 8.5 $\mu{m}$ and 13.0 $\mu{m}$, respectively. Elongation of cortex and metaxylem cell showed sigmoidal curves with final lengths of about 120 $\mu{m}$ for cortex cells and 650 $\mu{m}$ for metaxylem cells. Initial size and final size for both types were not affected by N level, but cell fluxes and cell elongation rates of cortical and metaxylem cells were about double in low N. Cell production rates were about 5 to 6 times higher in cortical cells than in metaxylem cells. Differences in N caused a larger change in cell production rate, duration of cell elongation, and relative cell elongation rate than did the genotypes. These data indicate that N application affects root growth longitudinally by changing cell production rate and elongation rate.

• Animal cells and systems
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• v.2 no.1
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• pp.65-69
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• 1998

The hippocampus and prefrontal cortex are regarded as the highest-order association cortices. The hippocampus has been proposed to store "cognitive maps" of external environments, and the prefrontal cortex is known to be involved in the planning of behavior, among other functions. Considering the prominent functional roles played by these structures, it is not surprising to find direct monosynaptic projections from the hippocampus to the prefrontal cortex. Rhythmic stimulation of this projection patterned after the hippocampal EEG theta rhythm induced stable long-term potentiation of field potentials in the prefrontal cortex. Comparison of behavioral correlates of hippocampal and prefrontal cortical neurons during an a-arm radial maze, working memory task shows a striking contrast. Hippocampal neurons exhibit clear place-specific firing patterns, whereas prefrontal cortical neurons do not show spatial selectivity, but are correlated to different stages of the behavioral task. These data lead to the hypothesis that the role of hippocampal projection to the prefrontal cortex is not to impose spatial representations upon prefrontal activity, but to provide a mechanism for learning the spatial context in which particular behaviors are appropriate.propriate.

• The Journal of the Korean dental association
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• v.54 no.2
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• pp.149-154
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• 2016

The glandular odontogenic cyst (GOC) is a rare cyst derived from odontogenic epithelium with a spectrum of characteristics including salivary gland features. It occurs more commonly in the mandible and most often in the anterior mandible. Radiographically, most cases present a well-defined unilocular or multilocular radiolucency with a cortical boundary. Despite no unique or pathognomonic clinical or radiographic features, the lesion shows potentially aggressive behavior. A 76-year-old male was referred to Gangneung-Wonju National University Dental Hospital with a chief complaint of slight swelling of the right mandible. Cone-beam computed tomography examination revealed a unilocular radiolucent lesion involving impacted third molar at the right posterior mandible. Slight lingual cortical thinning with suspected perforation was also shown. Histopathologically, multiple areas of cyst epithelium showed a glandular differentiation, resulting in mucoid-filled secretory cells and microcyst. Based on these findings, the final diagnosis was determined to be GOC.