• Biomolecules & Therapeutics
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• v.20 no.5
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• pp.470-476
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• 2012

Resveratrol, a chemopreventive agent, is rapidly metabolized in the intestine and liver via glucuronidation. Thus, the pharmacokinetics of resveratrol limits its efficacy. To improve efficacy, the activity of resveratrol was investigated in the context of sphingolipid metabolism in human gastric cancer cells. Diverse sphingolipid metabolites, including dihydroceramides (DHCer), were tested for their ability to induce resveratrol cytotoxicity. Exposure to resveratrol ($100{\mu}M$) for 24 hr induced cell death and cell cycle arrest in gastric cancer cells. Exposure to the combination of resveratrol and dimethylsphingosine (DMS) increased cytotoxicity, demonstrating that sphingolipid metabolites intensify resveratrol activity. Specifically, DHCer accumulated in a resveratrol concentration-dependent manner in SNU-1 and HT-29 cells, but not in SNU-668 cells. LC-MS/MS analysis showed that specific DHCer species containing C24:0, C16:0, C24:1, and C22:0 fatty acids chain were increased by up to 30-fold by resveratrol, indicating that resveratrol may partially inhibit DHCer desaturase. Indeed, resveratrol mildly inhibited DHCer desaturase activity compared to the specific inhibitor GT-11 or to retinamide (4-HPR); however, in SNU-1 cells resveratrol alone exhibited a typical cell cycle arrest pattern, which GT-11 did not alter, indicating that inhibition of DHCer desaturase is not essential to the cytotoxicity induced by the combination of resveratrol and sphingolipid metabolites. Resveratrol-induced p53 expression strongly correlated with the enhancement of cytotoxicity observed upon combination of resveratrol with DMS or 4-HPR. Taken together, these results show that DHCer accumulation is a novel lipid biomarker of resveratrol-induced cytotoxicity in human gastric cancer cells.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3017-3029
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• 2023

In the late in-vessel phase of a nuclear reactor severe accident, the internal heat transfer and crust evolution during the debris bed melting process have important effects on the thermal load distribution along the vessel wall, and further affect the reactor pressure vessel (RPV) failure mode and the state of melt during leakage. This study coupled the phase change model and large eddy simulation to investigate the variations of the temperature, melt liquid fraction, crust and heat flux distributions during the debris bed melting process in the hypothetical severe accident of HPR1000. The results indicated that the heat flow towards the vessel wall and upper surface were similar at the beginning stage of debris melting, but the upward heat flow increased significantly as the development of the molten pool. The maximum heat flux towards the vessel wall reached 0.4 MW/m². The thickness of lower crust decreased as the debris melting. It was much thicker at the bottom region with the azimuthal angle below 20° and decreased rapidly at the azimuthal angle around 20-50°. The maximum and minimum thicknesses were 2 and 90 mm, respectively. By contrast, the distribution of upper crust was uniform and reached stable state much earlier than the lower crust, with the thickness of about 10 mm. Moreover, the sensitivity analysis of initial condition indicated that as the decrease of time interval from reactor scram to debris bed dried-out, the maximum debris temperature and melt fraction became larger, the lower crust thickness became thinner, but the upper crust had no significant change. The sensitivity analysis of in-vessel retention (IVR) strategies indicated that the passive and active external reactor vessel cooling (ERVC) had little effect on the internal heat transfer and crust evolution. In the case not considering the internal reactor vessel cooling (IRVC), the upper crust was not obvious.

• Journal of the Korean Society of Food Culture
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• v.22 no.2
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• pp.254-260
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• 2007

This study was examined closely physiological activation and intended to present the possibility of developing food low-fat food. Developing carbohydrate fat replacer as materials for low-fat food made of Korean potato starch, it is expected that the new demand of fat replacer will be created. Potato starch was modified by chemical modification. The calorie of starch of GPS was measured to be 3.0 kcal/g, those of chemically modified starch, HPR showed 2.5 kcal/g respectively, suggesting that calorie is decreased by modified treatment. The appropriateness of processing food was experimented by substituting the existing oil and fat containing food with gel of starch and modified starch in constant rate through utilization of modified starch. When producing mayonnaise by substituting edible oil with gel of modified starch in 10-50%, calorie was reduced by 44${\sim}$45% when substituted by 50%, suggesting the potential of low-fat food. Measuring viscosity of mayonnaise by Brookfield viscometer, the mayonnaise with HPR showed high viscosity and the chemical modified starch group of EZ also showed high viscosity. Generally, the material property of mayonnaise tended to reduce in all measured items when oil and fat are substituted by starch substituting materials and the substituting materials increase. When it comes to the emulsification stability of mayonnaise with starch substituting materials, emulsification stability of all mayonnaise with starch substituting materials is lower than that of compared group. While the group with NL as commercial fat replacer showed emulsification stability which was slightly higher than group with modified starch and the substitution group of HPR showed higher emulsification stability. Sensory evaluation for low-fat mayonnaise by substituting oil the products substituted by modified starch was more preferred than general starch substituting products such as GPS. While NL as commercially fat replacer showed the hight preference, products with H40, EZ were also highly preferred.

• KSBB Journal
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• v.11 no.1
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• pp.8-14
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• 1996

Bacillus subtillis strains with transition state regulator mutations and a spore mutation were developed for the overexpression of apsE and for the enhancement of expression level. Among the many regulator genes, degU and hpr were chosen as a representative positive and negative regulator for the aprE, respectively. Spo II G was used for the construction of asporogeneous strains. All the mutants were constructed from two protease-deleted strain DB104 and the apsE gene was transformed with an integration vector pMK101. DB104(deg$U^h$(32) $his^+$)::pMK101(Cm) and DB104($\Delta$her(Em))::pMKl01(Cm) show 7-fold and about 2-fold increase in aprE expression level, respectively. But the effect of transition state regulator mutation on the aprE expression was diminished when the integrated aprE gene was amplified by the high concentration of chloramphenicol, i. e. 30 $\mu\textrm{g}$/ml. DB104($\Delta$spoIIG(Pm) degUh(32) his+)::pMK101(Cm) and DB104($\Delta$spoIIG(Pm) $\Delta$hpr(Em))::pMK101 double mutant show 10-fold and 3-fold increase in aprE expression level, respectively. The results suggest that sporulation mutation and transition state regulator mutation have independent and additive effect on the aprE expression, and the same gene dosage effect on the transition state regulator mutation was also identified.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.1
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• pp.15-21
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• 2004

The purpose of this research was to investigate loading rate of influent for acidogenic fermentation. Laboratory batch experiments were conducted, at $35^{\circ}C$, HRT 18hr, pH 6 and used 3.5L reactor. Loading rate of influent was varied 2.0 to 4.0g VSS/L, TOA concentration is decreased according to increasing loading rate Over 2.5g VSS/L. When loading rate is 2.0g VSS/L, hydrolysis percentage show the maximum value of 87%. Most of SCFA is consist of HAc, HPr, I-HBu and MBu. HAc concentration is 5,233mg/L in the 2.0g VSS/L condition. So, for this study, we think that limiting loading rate is 2.5g VSS/L. SCFA species was investigated to HAc, HPr, I-HBu and n-HBu during our studying. HAc/SCFA ratio is about 89.3%, SCFA production rate is highest to $1,104mg\;COD/L/d{\cdot}gPCOD$ for 2.0g VSS/L loading rate.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4685-4694
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• 2023

The ability to calculate the material density sensitivity coefficients of power with respect to the material density has broad application prospects for accelerating Monte Carlo-Thermal Hydraulics iterations. The second-order material density sensitivity coefficients for the general Monte Carlo score have been derived based on the differential operator sampling method in this paper, and the calculation of the sensitivity coefficients of cell power scores with respect to the material density has been realized in continuous-energy Monte Carlo code RMC. Based on the power-density sensitivity coefficients, the sensitivity coefficients of power scores to some other physical quantities, such as power-boron concentration coefficients and power-temperature coefficients considering only the thermal expansion, were subsequently calculated. The effectiveness of the proposed method is demonstrated in the power-density coefficients problems of the pressurized water reactor (PWR) moderator and the heat pipe reactor (HPR) reflectors. The calculations were carried out using RMC and the ENDF/B-VII.1 neutron nuclear data. It is shown that the calculated sensitivity coefficients can be used to predict the power scores accurately over a wide range of boron concentration of the PWR moderator and a wide range of temperature of HPR reflectors.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.829-835
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• 2000

The ptsH and ptsI genes of Lactococus lactis subsp. lactis ATCC 7962 (L. lactis 7962), encoding the general proteins of phosphotransferase system (PTS) components, HPr and enzyme I, respectively, were cloned and characterized. A 1.3 kb PCR product was obtained using a primer set that was hybridized to the internal region of the L. lactis 7962 pts HI genes and then subcloned into a low-copy number vector, pACYC184. The 5' upstream and 3' downstream region from the 1.3 kb fragment were subsequently clone using the chromosome walking method. The complete ptsHI operon was constructed and the nucleotide sequences determined. Two ORFs corresponding to HPr (88 amino acids) and enzyme I (575 amino acids) were located. The ptsHI genes of L. lactis 7962 showed a very high homology (84-90%) with those genes from other Gram-positive bacteria. A primer extension analysis showed that the transcription started at either one of two adjacent bases upstream of the start codon. Using a Northern analysis, two transcripts were detected; the first, a 0.3 kb transcript corresponding to ptsH and the second, a 2 kb transcript corresponding to ptsH and ptsI. The transcription level of ptsH was higher than that of ptsI. The concentration of the ptsH transcript in cells grown on glucose was similar to that in cells grown on lactose, yet higher than that in cells grown on galactose. The ptsI transcript was scarcely detected in cell grown on lactose or galactose. The ptsI transcript was scarcely detected in cells grown on lactose or galactose. The results of a sequence analysis and Northern blot confirmed that the ptsH and ptsI genes of L. lactis 7962 were arranged in an operon like other known ptsHI genes and the expression of the ptsHI genes was regulated at the transcriptional level in response to the carbon source.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1869-1879
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• 2000

A series of experiments were conducted for modeling the fate and effect of the coupled oxidation reduction reaction of ethanol and propionate recognized as important intermediates in anaerobic degradation metabolism. Anaerobic kinetics for conversion of propionate and the interaction with ethanol were investigated using the model of specific substrate priority utilization effect. Seed cultures for the experiment were obtained from an anaerobically enriched steady-state propionate master culture reactor (HPr-MCR), ethanol-propionate master culture reactor (EtPr-MCR) and glucose master culture reactor (Glu-MCR). Experiments were consisted of four phases. Phase I, II and III were conducted by fixing the propionate organic loading as 1.0 g COD/L with increasing ethanol loading of 0, 100, 200, 400 and 1,000 mg/L, to find metabolic interaction of ethanol and propionate degradation by each enriched anaerobic culture. In phase IV, different mixing ratios of Glu-MCR and HPr-MCR cultures with fixed propionate organic loading, 1.0 g COD/L, were applied to observe the propionate degradation metabolic behavior. In the results of this study, different pathways of propionate and ethanol conversion were found using a modified competitive inhibition kinetic model. Increase of $K_{s2}$ value reflected the formation of acetate followed by ethanol degradation. In addition. $K_3$ value was increased slightly as the reactions of acetate formation and degradation were occurred in acetoclastic methanogenesis.

• Journal of Nutrition and Health
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• v.24 no.1
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• pp.30-39
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• 1991

This study was designed to investigate the effects of dietary calcium. serum estrogen level and physical activity on the bone status of 116 healthy elderly women living in urban area. Current calcium intake was assessed by convenient method(refered to as Ca intake) and calcium containing food frequency method(refered to as Ca index) Daily activity record was used for the estimation of physical activity level, and serum estrogen level was measured from fasting blood of subjects. The rate of bone resorption was evaluated by the determination of hydroxyproline(Hpr) in fasting urine with correction for creatinine excretion. The results of this study are summarized as follows : 1) Average daily Ca intake of subjects was 621.4$\pm$155.8mg, which is above the Korean recommended dietary allowances. However 44.8% of the subjects consumed Ca below RDA level. Ca index score was significantly correlated with the bone status(P<0.05), Ca intake did not show significant correlation with the bone status although a positive trend of influence was evident. 2) Average serum estrogen level of subjects was 18.7$\pm$9.8pg Contrary to our anticipation. estrogen level did not show any significant relation to age and bone status. 3) Daily physical activity was classified into four categories by activity intensity : sedentary. moderate, active and severe. The average physical activity of subjects belong to moderate level. and the bone status was significantly related to the physical activity(P<0.01) 4) Among other influential factors such as age, pocket-money. family type. drinking, smoking and BMI, there was a significant difference between bone status and BMI(P<0.05). 5) Multiple regression analysis of variables showed that physical activity has greater effect than other variables when the entire subjects were taken into account. However. eliminating the subjects whose bone status rated as excellent(Hpr/cr<0.009), Ca index showed higher correlation than physical activity. These results have demonstrated that dietary calcium intake is the primary important factor for keeping good bone health and that bone status of subjects with a sufficient calcium intake is affected by various factors such as physical activity, age, smoking. BMI and others.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.435-439
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• 2015

THO/TREX complex plays an important role in transcriptional elongation, mRNA processing, nuclear RNA export, and genome stability. A fission yeast, Schizosaccharomyces pombe, SPBC577.04 gene encoding the ortholog of THOC5, a component of THO/TREX complex, was identified and characterized. The S. pombe thoc5 (spthoc5) is not essential for both growth and mRNA export, but deletion of the spthoc5 gene caused growth defect and slight accumulation of $poly(A)^+$ RNA in the nucleus. And the functional spThoc5-GFP protein is localized mainly in the nucleus. Co-immunoprecipitation analysis showed that the Hpr1(THOC1) protein, an evolutionally well-conserved component of THO/TREX complex, interacted with spThoc5 as well as Tho2(THOC2), another subunit of THO complex. These results suggest that S. pombe Thoc5 as a component of THO/TREX complex is also involved in mRNA export from the nucleus.