• 한국산학기술학회논문지
• /
• 제5권2호
• /
• pp.114-117
• /
• 2004

비소성 Pt/MoO₃와 200℃에서 소성한 Pt/MoO₃가 150℃에서 수소를 흡착하는 속도를 측정하였다. 소성된 Pt/MoO₃의 수소 흡착량이 비소성 Pt/MoO₃의 수소 흡착량보다 증가하는 것으로 관찰되었다. 상기 두가지 흡착 속도를 나타내는 Pt/MoO₃ 촉매에서 탈착량은 흡착량과 탈착 온도의 증가에 비례하는 것을 알 수 있었다. 또한 X-Ray Photoelectron Spectroscope(XPS) 결과로부터 Pt와 MoO₃간의 활성점에 존재하는 Cl의 존재가 수소 이동 속도를 결정하는 것으로 판단되었다.

• 대한한방내과학회지
• /
• 제18권1호
• /
• pp.147-155
• /
• 1997

This study was undertaken to determine whether Salviae-radix (SVR) exraction exerts benefical effect against oxidant-induced inhibition of tetraethylammonium (TEA) uptake which is actively secreted by renal proximal tubules. TEA uptake increased as function of incubation time to 60 min. When renal cortical slices were exposed to 50 mM $H_2O_2$, TEA uptake was significantly inhibited. The inhibition was significantly protected by addition of 0.5% SVR extraction. The benefical effect of SVR was dose-dependent over the concentration range of 0.1-1%; $H_2O_2$ (50 mM)-induced inhibition of TEA uptake was completely protected by 0.5-1% SVR extraction. $H_2O_2$ increased LDH release which was accompanied by an increase in lipid peroxidation in renal cortical slices. These changes were prevented by 0.5% SVR. These results suggest that SVR exerts benefical effect against oxidant-induced impairment of membrane transport function, this effect may be due to by an antioxidant action.

• Fisheries and Aquatic Sciences
• /
• 제9권1호
• /
• pp.30-37
• /
• 2006

We performed experiments on the uptake and excretion of dissolved organic phosphorus (DOP) using two toxic dinoflagellates, Alexandrium tamarense Lebour (Balech) and Gymnodinium catenatum Graham, isolated from Hiroshima Bay, Japan. ATP (adenosine triphosphate), UMP (uridine-5-monophosphate), G-6-P (glucose-6-phosphate) and Glycero-P (glycerophosphate) were used as DOP sources in preliminary uptake experiments. ATP was selected as the DOP species for the short-tenn uptake experiment because preliminary experiments showed it to be the DOP source used by both species. Although the $K_s$ values of A. tamarense and G. catenatum (5.63 and $7.61{\mu}M$, respectively) obtained from the short-term experiments for ATP were only slightly higher than those reported for dissolved inorganic phosphorus (DIP), the ${\rho}_{max}$ values (5.04 pmol/cell/h and 13.4 pmol/cell/h, respectively) were much higher. The DOP excretion rate in batch-culture experiments was estimated at 0.084 pmol/cell/h for A. tamarense and 0.012 pmol/cell/h for G. catenatum, accounting for about 30% and 25%, respectively, of the assimilated phosphorus. Our results suggest that the DIP-depleted conditions of Hiroshima Bay favor these two species by supporting their ability to use DOP.

• Journal of Dairy Science and Biotechnology
• /
• 제14권2호
• /
• pp.195-206
• /
• 1996

Cholesterol assimilated by Lactobacillus acidophilus ATCC 43121 was not metabolically degraded in that most of it was recovered with the cells. Cells grown in the presence of cholesterol micelles and bile salts were more resistant to Iysis by sonication than those grown in their absence, suggesting a possible alteration of cellular membranes. Cholesterol assimilation occurred during growth at pH 6.0, the amount of which was more than that by cells grown without pH control. Cholesterol assimilated by cells was recovered in the membrane fractions of cells both grown at pH 6.0 and without pH control. The effect of unsaturated fatty acids on cholesterol assimilation was not clear, since there was no significant (P> 0.05) difference in the amount taken up from micelles prepared using L-${\alpha}$-phosphatidylcholine, dioleoyl or L-${\alpha}$-phosphatidylcholine, distearoyl. Without Tween 80, little, if any, cell growth or cholesterol uptake was observed. In the presence of 0.05% Tween 80, cholesterol uptake increased dramatically as did growth. However, as the amount of Tween 80 increased beyond 0.05%, cholesterol uptake decreased while the amount of growth remained the same.

• Clinical and Experimental Reproductive Medicine
• /
• 제18권2호
• /
• pp.153-162
• /
• 1991

The present study was undertaken to clarify the role of calcium ion as a factor for the maturation of follicle-enclosed mouse oocytes. Follicles were isolated with two sharp needles under a stereomicroscope from mouse(ICR) ovaries which were treated PMSG 5 IU 45 hours previously. Isolated follicles were cultured for 14-16 hours in an organ culture system at $37^{\circ}C$, 5% $CO_2$ in air and in a 100% humidified incubator by treatment of hCG, EDTA and $^{45}Ca^{++}$. Culture medium was Modified Hank's Balanced Salt Sol. (MHBS) and addition of hCG (human chorionic gonadotropin) was made into two doses level 0.4 IU and 0.8IU from the stock sol. and also $^{45}Ca^{++}$ was treated in the culture medium. To explain the role of calcium, calcium chelating agent EDTA was treated to the culture of the mouse follicle-enclosed oocytes. Two observations were made in the present study; nucleus phase and $^{45}Ca^{++}$ uptake into the oocyte. HCG induced oocyte maturation in the follicle about two folds as much as the control group, whereas there is no difference in oocyte maturation between 0.4 IU and 0.8 IU of hCG. Optimum level of hCG seems to be 0.4 IU/ml in the mouse follicle culture. HCG stimulated $^{45}Ca^{++}$ uptake into the oocyte of the follicles by two folds. $^{45}Ca^{++}$ uptake in the control group is about 2.5 folds in comparison of the EDTA(1.71mM) treated group. However, calcium uptake in the EDTA treated groups tends to increase depending on the decrease of EDTA concentration. These observations suggest that firstly, hCG stimulates maturation of the oocyte of the follicle, secondly, $Ca^{++}$ influx is induced by hCG and thirdly, $Ca^{++}$ influx by the treatment of EDTA decreases as a dosage-dependent process. This $Ca^{++}$ uptake may take place by the changes of permeability which was induced by hCG treatment. That is, $Ca^{++}$ influx may trigger the resumption of oocyte maturation. It is further necessary in the future study how this $Ca^{++}$ uptake is induced by hCG and increases permeability of the follicle and oocyte.

• Asian-Australasian Journal of Animal Sciences
• /
• 제15권8호
• /
• pp.1210-1214
• /
• 2002

The large and rapid changes of glucose utilization in lactating mammary tissue in response to changes in nutritional state must be largely related by external signal of insulin. This also must be related with the quantity and composition of the diet in vivo. To characterize the mode of gut extract protein with insulin, in vitro experiment was conducted with HC11 cells. The gut extract protein has not only the same effect as insulin alone but also the synergistic effect with insulin in 2-Deoxy[3H] glucose uptake. Although the gut extract did not modulates glucose uptake via increasing the rate of translation of the GLUT1 protein, northern blot analysis indicated that the gut extract protein increased the expression of GLUT1 mRNA by a threefold and also there was a dose-dependent increase in the expression of GLUT1 mRNA. The gut extract protein is therefore shown to be capable of modulating glucose uptake by transcription level with insulin in HC 11 cells.

• Journal of Pharmaceutical Investigation
• /
• 제20권4호
• /
• pp.223-228
• /
• 1990

The contribution of endogenous transport systems to the blood-brain barrier (BBB) transport of basic and acidic drugs was studied by using a carotid injection technique in rats and an isolated bovine cerebrovascular disease state were compared between the normotensive rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP) which have been well established as an animal model with pathogenic similarities to humans. Basic drugs such as eperisone, thiamine and scopolamine inhibited, in a concentration dependent manner the in vivo uptake of $[{^3}H]choline$ through BBB, whereas amino acids and acidic drugs such as salicylic acid and valproic acid did not inhibit the uptake. The uptake of $[^3H]choline$ by B-CAP increased with time and showed a remarkable temperature dependency. The uptake of $[^3H]choline$ by B-CAP showed the very similar inhibitory effects as observed in the in vivo brain uptake, and was competitively inhibited by a basic drug, eperisone. The in vivo BBB uptakes of $[^3H]acetic$ acid and $[^{14}C]salicylic$ acid were dependent on pH of the injectate and the concentration of drugs. Several acidic drugs such such as salicylic acid, benzoic acid and valproic acid inhibited the in vivo uptake of $[^3H]acetic$ acid, whereas amino acid, choline and a basic drug such as eperisone did not inhibit the uptake. The uptake of acetic acid by B-CAP was competitively inhibited by salicylic acid. The permeability surface area product (PS) through BBB for $[^3H]choline$ in SHRSP was significantly lower than that in WKY. The concentration of choline in the brain dialysate in SHRSP was about half of that in WKY, while no significant difference was observed in the plasma concentration of choline between SHRSP and WKY. No significant difference was observed in the transport of monocarboxylic acids, glucose and neutral amino acid through BBB between SHRSP and WKY. From these results, it was concluded that BBB transport system of choline contributes to the transport of basic drugs through BBB, that acidic drugs can be transported via a moncarboxylic acid BBB transport system and that the specific dysfuntion of the BBB choline transport in SHRSP was ascribed to the reduction of the maximum velocity of choline concentration in the brain interstitial fluids.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권11호
• /
• pp.1690-1694
• /
• 2003

The large and rapid changes of glucose utilization in lactating mammary tissue in response to changes in nutritional state must be largely related by external signal of insulin. This also must be related with the quantity and composition of the diet in vivo. To characterize the mode of growth factors and gut regulatory peptides with insulin, in vitro experiment was conducted with HC11 cells. All the growth factor alone and the combinations of growth factors significantly (p<0.05) increased in glucose uptake. Insulin, EGF and IGF-1 exhibited a stimulation of glucose uptake for at least 24 h. Furthermore, the highest (p<0.05) synergistic effect was shown in EGF plus IGF-1 and the second synergistic effect in insulin plus EGF while no synergistic effect was found between insulin and IGF-1. However, the gut regulatory peptides neither potentiated nor inhibited the action of insulin on glucose uptake. Although growth factors did not modulates glucose uptake via increasing the rate of translation of the GLUT1 protein, RT-PCR analysis indicated that the growth factors significantly (p<0.05) increased the expression of GLUT1. The growth factors are therefore shown to be capable of modulating glucose uptake by transcription level with insulin in HC 11 cells.

• Journal of the korean society of oceanography
• /
• 제37권1호
• /
• pp.45-50
• /
• 2002

New production (NP) values in well-mixed waters of the Yellow Sea were estimated using two different methods and were compared with each other; one is from the quantum yield model of nitrate uptake and chlorophyll ${\alpha}$-specific light absorption coefficient, and the other is from a traditional $^{15}N$-labelled stable isotope uptake technique. The quantum yields of nitrate uptake were highly variable, ranging from 0.0001 to 0.04 mol $NO_3Ein^{-1}$, and the small values in this study might have resulted from either the partitioning into nitrate uptake of little portions of light energy absorbed by phytoplankton or that phytoplankton may predominantly utilize other N sources (E. G. ammonium and/or urea) than nitrate. The estimates (0.54-8.47 nM $h^{-1}$) of NP from the quantum yield model correlated well ($r^2$=0.67, p<0.1) with those (0.01-4.93 nM $h^{-1}$) obtained using the $^{15}NO_3$ uptake technique. To improve the ability of estimating NP values using this model in the Yellow Sea, more data need to be accumulated in the future over a variety of time and space scales.

• Journal of Plant Biology
• /
• 제30권4호
• /
• pp.277-285
• /
• 1987

Undifferentiated suspension cells had the ability to transfer glucose and fructose actively, but the suspension culture cells were unable to transfer saccharide without previously splitting to monosccarides. The uptake of fructose showed the low- and high-affinity system compared to of glucose, which possessed only one saturable uptake system. In this paper, the low affinity system of the uptake of fructose has been studied intensively. Glucose did not inhibit the low affinity system of fructose competitively. The Km value was 47 mM for fructose, 7.4 mM for glucose and Vmax was 69 $\mu$mol/h.g fresh weight for fuctose, 9.8 $\mu$ mol/h.g fresh weight for glucose. Metabolizer inhibitors, both 50 $\mu$M of CCCP and DNP, inhibited 70% of the uptake of the low affinity system of fructose. The proton ions were accompanied by the uptake of fructose. The stoichiometry showed ratio of proton to fructose was 0.17. The mechanism ofthe uptake was fructose-proton-symport. The molecules of fructose accmululated inside 25 times more than outside. Therefore, the low affinity system of fructose was not mere diffusion, but depended on metabolic energy and thus transported actively. The importance of this system was discussed.