• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.537-542
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• 2004

To reveal the relationship between the changes in the growth and photo- synthesis induced by low dose radiation, red pepper (Capsicum annuum L.) plants were serially irradiated three times with gamma rays of 0.5, 1, 2, 3, and 4 Gy. The plant growth was monitored by the fresh weight, the stem length, and the leaf length & width. All the irradiation groups (0.5-4 Gy) were stimulated in growth at 1 day after the $1^{st}$ irradiation (DA1I), but rather inhibited at 3 days after the $3^{rd}$ irradiation (DA3I). The maximum photochemical efficiency (Fv/Fm), the photochemical quenching (qP), the non-:photochemical quenching (NPQ) and the apparent rate of the photosynthetic electron transport (ETR) were used to represent the changes in the photosynthesis by the serial irradiation. The irradiation groups except 0.5 Gy had higher Fv/Fm values at 3 DA3I than the control one. After the 3$^{rd}$ irradiation, the qP values appeared to be a little lower in the 1-4 Gy groups than in the control and 0.5 Gy ones. In contrast, the NPQ values were rather higher in the irradiation groups except 0.5 Gy. During the whole experimental period, the ETRs decreased in the control group but remained relatively constant in the 4-Gy one. In conclusion, the results obtained indicate that the stimulatory effect of ionizing radiation on the plant growth was determined by the incident dose of the single irradiation rather than by the cumulative one of the serial irradiation. They also demonstrate that the growth stimulation induced by a low dose radiation could not be positively correlated with an alteration in the photosynthesis. Additionally, we discuss in text that an ionizing radiation may partly protect the leaf senescence by delaying the development of the plants.

• The Korean Journal of Physiology
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• v.17 no.2
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• pp.125-133
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• 1983

Red cell glycolytic intermediates, metabolites and metabolic ratios were studied. Glycolytic intermediates were measured in neutralized perchloric acid extracts of red cell suspensions after 3 hr incubation at $37^{\circ}C$ in the presence and absence of saponin. Adenosine triphosphate(ATP), adenosine diphosphate(ADP), pyruvate and lactate were measured by enzymatic procedures involving stoichiometric oxidation or reduction of a pyridine nucleotide. Glucose was determined using glucose oxidase after zinc hydroxide extraction. The redox state was calculated from the lactate dehydrogenase equilibrium. Adenosine triphosphatase activity(ATPase) was measured by determining the amount of phosphate released from ATP by washed erythrocyte membranes(ghost) during 20 min. incubation. Both total hydrolysis and the amount of hydrolysis that occured in the presence of ouabain were measured. The second measurement yields Mg-ATPase and represents nonspecific ATPase activity of the membranes. The difference between total and Mg-ATPase activity can be attributed to Na-K-ATPase. For the measurement of sodium fluxes, human erythrocytes were preincubated in $^{22}Na$ for 3 hr at $37^{\circ}C$, washed and suspended in a tracer-free medium. The amount of $^{22}Na$ transported out of cells at any time was determined by analysis of supernatant samples taken at various time after addition of the labeled cells to isotope-free medium. The cells and medium were separated and the radioactivity appearing in the medium was measured. From the total radioactivity in the suspension and the radioactivity appearing in the medium at known time, the rate constant for sodium release was computed. The results are summarized as follows: 1) ATP and ATP/ADP were found to increase at every concentration of saponin tested whereas ADP declined at every cone. of saponin. The increase in pyruvate and lactate were observed at every cone, of saponin and thus $NAD^+/NADH$ computed from pyruvate/lactate also increased. Glucose utilization was stimulated by saponin. 2) $Na^+-K^+-ATPase$ activities showed a biphasic response to saponin, first increasing in lower concentration and then decreasing in higher concentration of saponin. 3) The efflux of sodium was significantly increased by saponin in the range of 5 to 10 mg%. The stimulatory effect of saponin on the rate constants for active(ouabain-sensitive) sodium efflux was inhibited by addition of ouabain.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.1
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• pp.101-108
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• 1998

We investigated the effect of ${\alpha}-subunit$ of the stimulatory GTP-binding protein ($G{\alpha}_s$) gene mutation on the expression of the thyrotropin-releasing hormone (TRH) receptor (TRH-R) gene in GH3 cells and in growth hormone (GH)-secreting adenomas of acromegalic patients. In the presence of cyclohexicmide, forskolin and isobutylmethylxanthine, cholera toxin, and GH-releasing hormone (GHRH) decreased rat TRH-R (rTRH-R) gene expression by about 39%, 43.7%, and 46.7%, respectively. Transient expression of a vector expressing mutant-type $G{\alpha}_s$ decreased the rTRH-R gene expression by about 50% at 24 h of transfection, whereas a wild-type $G{\alpha}_s$ expression vector did not. The transcript of human TRH-R (hTRH-R) gene was detected in 6 of 8 (75%) tumors. Three of them (50%) showed the paradoxical GH response to TRH and the other three patients did not show the response. The relative expression of hTRH-R mRNA in the tumors from patients with the paradoxical response of GH to TRH did not differ from that in the tumors from patients without the paradoxical response. Direct PCR sequencing of $G{\alpha}_s$ gene disclosed a mutant allele and a normal allele only at codon 201 in 4 of 8 tumors. The paradoxical response to TRH was observed in 2 of 4 patients without the mutation, and 2 of 4 patients with the mutation. The hTRH-R gene expression of pituitaty adenomsa did not differ between the tumors without the mutation and those with mutation. The present study suggests that the expression of TRH-R gene is not likely to be a main determinant for the paradoxical response of GH to TRH, and that $G{\alpha}_s$ mutation may suppress the gene expression of TRH-R in GH-secreting adenoma. However, a certain predisposing factor(s) may play an important role in determining the expression of TRH-R.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.417-424
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• 1996

The present study was done to examine the involvement of protein kinase C and protein tyrosine kinase in intracellular $Ca^{2+}$ mobilization in C5a-stimulated neutrophils. Although protein kinase C inhibitors, staurosporine and H-7 inhibited intracellular $Ca^{2+}$ release in C5a-stimulated neutrophils, they did not affect $Ca^{2+}$ influx across the plasma membrane and elevation of $[Ca^{2+}]_i$ C5a-induced intracellular $Ca^{2+}$ release and $Ca^{2+}$ influx were inhibited by protein tyrosine kinase inhibitors, genistein and methyl-2,5-dihydroxycinnamate. ADP-evoked elevation of $[Ca^{2+}]_i$ was inhibited by genistein and methyl-2,5-dihydroxycinnamate but was not affectd by staurosporine and H-7. Genistein and methyl-2,5-dihydroxycinnamate reduced the store-regulated $Ca^{2+}$ influx in thapsigargin-treated neutrophils, while the effect of staurosporine and H-7 was not detected. When neutrophils were preincubated wih phorbol 12-myristate 13-acetate, the stimulatory effect of C5a on the elevation of $[Ca^{2+}]_i$ was reduced. These results suggest that protein tyrosine kinase may be involved in control of intracellular $Ca^{2+}$ release and $Ca^{2+}$ influx across the plasma membrane in C5a-activated neutrophils.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.88-93
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• 2007

The preventive effect of Lentinus edodes extract (LE) against constipation was studied in rats. Rats were pretreated with LE contained in drinking water at the concentration of 10%, 20% and 40% over 30 days. Constipation was induced by subcutaneous injection of loperamide (4 mg/kg/day) 3 days prior to sacrifice. Treatment of loperamide resulted in decreases in the number and wet weight of fecal pellets, and increase in the number of fecal pellet in the distal colon and cecocolon weight. In contrast, the number and wet weight of fecal pellets were increased, and the number of fecal pellet in the distal colon and the cecocolon weight were decreased in LE-pretreated groups compared to the loperamide-treated group. Blood parameters such as white blood cell, red blood cell, hemoglobin, hematocrit, platelet, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, and serum alanine transaminase, aspartate aminotransferase and alkaline phosphatase activities, and blood urea nitrogen and creatinine values were not significantly different between the groups. In addition, LE (0.5 mg/mL) increased spontaneous contractile activity, which was reduced by atropine or loperamide in isolated rat ileum. Theses results suggest that the improvement of constipation symptoms in LE-pretreated rats resulted from a stimulatory effect of LE on intestine contractile activity.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9341-9346
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• 2014

Acanthopanax trifoliatus (L) Merr (AT) is commonly used as an herbal medicine and edible plant in some areas of China and other Asian countries. AT is thought to have anticancer effects, but potential mechanisms remain unknown. To assess the anticancer properties of AT, we exposed prostate cancer cells to AT extracts and assessed cell proliferation and signaling pathways. An ethanol extract of AT was suspended in water followed by sequential extraction with petroleum ether, ethyl acetate and n-butanol. PC-3 cells were treated with different concentrations of each extract and cell viability was determined by the MTT and trypan blue exclusion assays. The ethyl acetate extract of the ethanol extract had a stronger inhibitory effect on growth and a stronger stimulatory effect on apoptosis than any of the other extracts. Mechanistic studies demonstrated that the ethyl acetate extract suppressed the transcriptional activity of NF-${\kappa}B$, increased the level of caspase-3, and decreased the levels of phospho-Erk1/2 and phospho-Akt. This is the first report on the anticancer activity of AT in cultured human prostate cancer cells. The results suggest that AT can provide a plant-based medicine for the treatment or prevention of prostate cancer.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.300-308
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• 2000

The Fibroblast growth factors(FGFs) plays an important role in the control of osteogenesis during skeletal development. Especially, FGF-2 is a potent mesodermal inducer during embryogenesis and FGF receptors (FGFRs) messages are strongly expressed in developing bones. In this study, we investigated the effect of bFGF on osteopontin(OPN) gene expression in ST-2 cells and tried to elucidate the mechanism of its stimulatory effects. The obtain results were as follows; The treatment of bFGF(1ng/ml) upregulates OPN, fibronectin mRNA levels and downregulates type I collagen mRNA levels. But, there was no remarkable difference in alkaline phosphatase mRNA levels between two groups. The OPN gene expression increased in a dose-dependent manner up to 10ng/ml and OPN gene began to occur at around 3h with continuous increase up to 24h then decreased to basal level at 48h. 30 minutues pretreatment with cycloheximide (500ng/ml), a protein synthesis inhibitor, prior to addition bFGF resulted in blocking bFGF induced OPN expression. These results suggest that bFGF increased the level of OPN mRNA in a dose and time-dependent manner via the synthesis of certain transcriptional regulatory proteins.

• Microbiology and Biotechnology Letters
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• v.11 no.3
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• pp.205-210
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• 1983

Extracellular $\beta$-galactosidase was prepared from a culture of Lactobacillus sporogenes, a spore-forming lactic acid bacterium. The enzyme functioned optimally at pH 6.8 and at 6$0^{\circ}C$ o-nitrophenyl-$\beta$-D-galactopyranoside (ONPG) in 0.05M sodium phosphate buffer. The activation energy of the enzymatic hydrolysis of ONPG was about 16,000 cal/mole below $50^{\circ}C$ and 11,300 cal/mole above the temperature. It was fairly stable over a pH range from 4.0 to 8.0 losing only less than 30% of its activity after hearting at 6$0^{\circ}C$ and pH 6.8 for 3 hours. Metal ions showed no significant effect on the enzyme activity, whereas L-cysteine exerted a slight stimulatory effect at the concentration of 10mM. The km values were 1.48mM for ONPG and 64.5mM for lactose. Hydrolysis of ONPG by the enzyme was product-inhibited by galactose (Ki=13.3mM, competitive inhibition) and by glucose(Ki= 11.4mM, uncompetitive type). The enzyme activity was also noncompetitively inhibited in the presence of lactose (Ki= 17.8mM).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.295-305
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• 1994

Greenhouse and laboratory studies were conducted to investigate the allelopathic potential of alfalfa and vetch residues on soybean and corn using various extract concentrations (0, 5, 10, 15 and 20%, w/v) and residue rates (0, 0.25, 0.5, 0.75 and 1%, w/w). Aqueous extracts of alfalfa (Medicago sativa L.) and vetch (Vicia spp.) exhibited an allelopathic effect on soybean and corn seed germination, seedling length and weight. The degree of inhibition significantly increased as the aqueous extract concentration increased. Alfalfa and vetch 20% extracts reduced soybean seed germination, seedling length and weight by 35%, 57%, 32% and 15%, 42%, 25% respectively, when compared to control. Corn germination, seedling length and weight was inhibited by 20%, 23%, 38% by alfalfa and 19%, 18%, 35% by 20% vetch extracts. Alfalfa and vetch extracts inhibited secondary root formation and branching as the extract concentration increased. Alfalfa and vetch 20% extracts inhibited by 41% and 32% secondary root numbers, respectively as compared to control. It was found that the aqueous extract of alfalfa resulted in greater reduction in germination, seedling length and weight of soybean than that of vetch. Alfalfa and vetch 1% residue rate inhibited soybean plant height by 30% and 10%, leaf area by 31% and 23%, and dry weight by 18% and 1%, nodule number by 27% and 20% also. Alfalfa and vetch residue significantly enhanced plant height, leaf area and dry weight of corn. The maximum stimulation occurred with 0.25% and 1% of alfalfa and vetch residue rates, respectively. Plant height, leaf area, and dry weight increased by 23%, 59%, 58% and 17%, 52%, 94% with alfalfa and vetch residues of 0.25% and 1%, respectively. This study demonstrates that there is an allelopathic potential resulting from alfalfa and vetch residues on soybean growth and yield. It also suggests that these residues may affect crop growth and development due to the inhibitory or stimulatory effects of allelochemicals existing in the residue.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.225-235
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• 1986

Effects of anions on p-Aminohippurate (PAH) transport across the basolateral membrane (BLM) were studied. Basolateral membrane vesicles were isolated from rabbit renal cortex by using a self-orienting Percoll-gradient centrifugation and $Mg^{2+}-precipitation$. The characteristics of the membrane vesicles was examined by marker enzyme activity, membrane orientation and transport studies. The Na-K-ATPase activity in the fraction containing BLM vesicles was enriched 9·fold, and the alkaline phosphatase activity in the fraction containing BBM vesicles was increased 9-fold, compared with those of the homogenate. The transport properties of the two membrane preparations were studied by a rapid filtration technique. The uptake of PAH by BLM was sensitive to changes in medium osmolarity and inhibited by probenecid. When the uptake of $50{\mu}M$ PAH in voltage-clamped BLM vesicles was determined in the presence of various anions in the incubation medium, cis inhibitions by $SO_4\;and\;SSO_3$ were observed in the presence of sodium gradient (out>in). Sodium-dependent PAH uptake was inhibited competitively by external $SO_4$ PAH uptake in BLM vesicles loaded with 20 mM acetate and $SO_4\;or\;200\;{\mu}M$ PAH was significantly stimulated as compared with unloaded vesicles. The extent of trans-stmulation of PAH uptake by $SO_4$. was increased with the inside concentration of $SO_4$. This trans-stimulatory effect by $SO_4$, was observed to be additive in the presence of Na gradient and completely inhibited by 2 mM probenecid and 1 mM SITS. These results demonstrate that PAH/anion exchange is present in BLM of renal cortex and in this exchange mechanism inorganic as well as organic anions are involved as substrates.