• Journal of Plant Biology
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• v.8 no.1_2
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• pp.19-23
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• 1965

Interaction occuring among the different Ca concentrations, pH and temperatures in the promotive effect of Ca in pollen growth was studied by using pollen from Crinum asiaticum and Cryptostegia grandiflora. Data for pollen tube elongation were found to be more indicative of representing the promotive action of Ca ion in pollen growth than those for pollen germination, and were served to evaluate the experimental results. The pollen growth increased as the concentration of Ca increase. The optimal pH range for pollen growth shifted from the lower pH to the higher as the concentration of Ca increase. The characteristic Ca effect was disappeared, and no pH effect at various ranges was observed when pollen grains were grown at the low temperature(8$^{\circ}C$). The Ca effect became quite pronounced if temperature were raised. The Ca effect became even mroe striking if the condition was in higher pH ranges (weak alkaline). Higher pH ranges were found to be more favorable for the Ca action, whereas higher temperature was required to bring about more pronounced Ca effect. Thus, the longest pollen tube was obtained with the highest pH, temperature adopted for the medium supplemented with Ca in the present experiment, and the shortest tube with the lowest temperature applied at the highest pH. Pectin synthesis in pollen tube was considered as a metabolic process, whereas Ca binding in pectin of the pollen tube wall as non-metabolic in nature. Disappearance of Ca effect at the low temperature was probably brought about by blocking the metabolic synthesis of pectin, and nonmetabolic Ca binding seems to take place more extensively with higher concentrations of Ca and at higher pH levels than the lower.

• The Journal of the Korean Society for Microbiology
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• v.6 no.1
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• pp.29-40
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• 1971

Various kinds of antibiotics are generally believed to have inhibitory effects on the antibody response. However, as polymyxin B which belongs to the cyclic polypeptide group of antibiotic was found to have some enhancing effects on the antibody response of rabbits to enterobacterial common antigen(CA) under specified conditions, experiments were carried out on this problem with the following results. 1. When mixture of polymyxin B and CA derived from Salmonella typhimurium(STM) was treated 30 minutes at $37^{\circ}C$ and injected three times into rabbits by intravenous route, the antibody response to CA was weaker than rabbits injected CA only. 2. Mixture of polymyxin B and CA showed a marked antibody production when injected into rabbits primed with small amounts of heat-extracted antigen of STM, while the injection of CA alone showed low titers of response. 3. Mixture of polymyxin B and heat-extracted CA-containing antigen of Escherichia coli 014 also showed a increased antibody production than CA alone in rabbits primed with antigen of STM. 4. The effect of polymyxin B appeared in different ways. This antibiotic did not enhance the CA antibody response in rabbits primed with small amounts of E. coli 0111 and 055, but enhance in rabbits primed with Shigella flexneri. 5. No enhancing effect on the antibody response was observed by polymyxin B in rabbits primed with CA. 6. No enhancing effect on the antibody response was also noted in rabbits primed with STM antigen in case polymyxin B and CA were administered simultaneously but in veins of different places. 7. Bacitracin did not enhance the CA antibody response in primed rabbits with STM antigen, but neomycin slightly enhance the response. 8. Lipopolysaccharide showed no priming effect on the CA antibody response, and no enhancement of the CA antibody response in rabbits printed with STM. 9. The priming effect of STM antigen against CA antibody response was very weak as compared with the effect of CA derived from STM antigen.

• The Journal of Information Systems
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• v.21 no.2
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• pp.115-133
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• 2012

According to previous studies, the effect of intrinsic motivation related variables such as cognitive absorption (CA) on the use of information technology(IT) should be mediated by the conscious intention. However, CA, which is a thought of previous emotional experience, a deep involvement with a software, may be one of environmental cues stimulating the use of IT independently of conscious intention. The objective of this study is to show the direct effect of CA on the automatic use of IT. For this purpose, as well as the relation between CA and use, two relations, CA-intention and intention-use, were also suggested as hypotheses, which will show that conscious intention would not fully mediate the relation between CA and automatic use. Moreover, for seeing the effects of CA as time passes, the proximal effect, which is short term and transitory effect, and the distal effect, which is long term and lingering, were simultaneously included in hyptheses. Finally, the effect of past use was also suggested as a hypothesis which aimed to show that automatic use would be controlled mostly by habit rather than not only intention but also CA. For the empirical validation of the hypotheses, 174 users of 'Cyworld', one of most influential social network services, were longitudinally surveyed, which showed that the hypotheses were accepted.

• Journal of Nutrition and Health
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• v.32 no.1
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• pp.30-39
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• 1999

This study was designed to investigate the effect of Ca supplementation of 1,000mg per day for 53 weeks on lipid, Na, and K metabolism and on blood pressure in postmenopausal women. The subjects were 12 healthy women aged from 60 to 70 years. They were divided into two groups : the placebo(control group) and the Ca supplemented(1,000 mg/day) group(Ca group). Metabolic studies were conducted twice in the 1st and the 53rd weeks. The results were as follows : Serum triglyceride, total cholesterol and LDL-choesterol levels tended to be decreased after the experiment. Serum VLDL-cholesterol lowering effect was observed with Ca supplementation(p<0.05), and also the significantly elevated HDL/(LDL+VLDL) ratio in Ca supplemented subjects whose average Na intake was as high as 4.9g per day. This phenomena was accompanied with increased Na retention and increased Na excretion in feces, but with decreased urinary Na in Ca supplemented group. However, considering much higher Na reteniton in the control group at the end of experiment(control va Ca ; 1272.3mg vs 732.9mg), Ca supplementation may have some beneficial effects on Na blance. Serum aldosterone level increased significantly in the Ca group after the exsperiment(p<0.05). With these normotensive subjects, there were no level increased significantly in the Ca group after the experiment(p<0.05). With these normotensive subjects, there were no pronounced effect of Ca supplementation on blood pressure, however, decrease in diastolic blood pressure were observed at the 14th week and end of the experiment(p<0.05). In summary, the Ca supplementation on postmenopausal Koran women appears to exert a desirables effect on blood lipid patterns related to the coronary heart diseases and to be beneficial in controlling diastolic blood pressure. Further studies with hypertensive or/and hyperlipidemic subjects are required to clarify the effect of Ca supplementation in Koreans.

• Journal of Plant Biology
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• v.30 no.4
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• pp.249-255
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• 1987

The effect of polyamine and Ca2+ on D-glucose-6-phosphate cyclohydrolase activity was studied in Daucus carota root. The enzyme activity was reduced in response to increase in concentration of Ca2+, not the Ca2+-calmodulin complex. The inhibition effect due to Ca2+ was reversed by polyamine, especially remarkable at low concentration of Ca2+. The effect of the Ca2+ on the enzyme seemed to compete with polyamine according to the Lineweaver-Burk plot. The enzyme activity from carrot root protoplast cultured in the prescence of verapamil was higher than that of the control. Such cumulative results suggest that the inhibition by the Ca2+ and enhancement or reversal by polyamine could regulate the biosynthesis of pectin and hemicellulose to some extent.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.943-949
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• 1996

Bone mineral density depends largely on the status of dietary minerals such as Ca, P, Mg, and F and proteins, physical activities, parathyroid hormone(PTH), calcitonin(CT), and vitamin D. The decrease of bone density often results in bone fractures and osteoporosis which is prevalent among postmenopausal women. This study was intended to examine the role of parathyroid hormone, calcitonin and cholecaliferol in bone density of mice that were fed different dual photon energy beams. We have measured three major parts of the bone : whole body, head and femur. The results are summarized as follows : 1) Bone mineral density (BMD) was more increased by feeding high Ca diet compared to that of the low Ca diet. 2) Both PTH and Vit D3 enhanced BMD in all of the different Ca levels. 3) When the dietary Ca was deequate CT showed a synergistic effect with PTH in boosting bone density, while CT+Vit D3 showed a negative effect. 4) CT tended to inhibit the effect of increasing bone density by PTH and Vit D3 in medium and low Ca groups. 5) The effect of increasing bone density by PTH in the head of mouse increased when dietary Ca was lower : The increment of bone density by PTH in high, medium, and low Ca was 3%, 8%, 19%, respectively. 6) Femur bone density was affected significantly by dietary Ca levels than hormones. The above observations indicate that bone mineral density can be improved by high dietary Ca and hormone injections including PTH, CT and cholecalciferol, and thus proper dietary and hormonal treatment may be used in preventing bone fractures and osteoporosis.

• Journal of Plant Biology
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• v.33 no.4
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• pp.315-320
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• 1990

We investigated the interaction of auxin and Ca2+ on coleoptile segment elongation in seedlings of Zea mays L. Seedlings imbibed and raised either in the presence of 10 mM CaCl2 (HC), or in the absence of Ca2+ (LC) were used. Exposure to 10-5M auxin of coleoptiles from either HC or LC seedlings resulted in strong promotion of elongation. However, longer latent period (90 min) of the auxin effect was observed in HC than in LC seedlings (20 min). The length of latent period observed in HC coleoptiles was proportional to the concentration of CaCl2. The latent period of auxin effect observed in HC seedlings was abolished by pretreatment of the coleoptiles with TMB-8 which inhibits IP3-induced Ca2+ release from the tonoplasts. In segments of LC seedlings, the promotive effect of IAA (10-5M) was abolished by treatment with 5 mM calcium but was reversible upon treatment of the segments with 5 mM EGTA. These results suggest that the effect of auxin on coleoptile elongation is closely related to intracellular Ca2+ level.

• Journal of Nutrition and Health
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• v.35 no.1
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• pp.45-52
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• 2002

This study was to investigate 1) the correlation of serum Ca, with depression and anxiety ; and 2) the effect of Ca intake on those symptoms. The subjects were three females and two males who were 53-66 years old with the severe subjective symptoms of depression and anxiety. They have taken more than twice Ca of RDA(recommended dietary allowances for Koreans) daily for 6 months(dietary treatment). The prestudy Ca intake of the subjects was low: 60% of RDA for Koreans. Their serum Ca concentration was also low: 6.67 $\pm$ 0.15mg/d1 before the dietary treatment. They expressed severs depression and anxiety, with high self scores in a psychological test. Their serum Ca concentration increased to 8.32 $\pm$ 0.17mg/dl after six months of dietary treatment, while the symptoms of depression and anxiety decreased significantly after two months and nearly disappeared after six months. This result seemed to be an effect of the dietary high Ca intake. Serum Ca and the psychological states of depression and anxiety correlated negatively, and the coefficients of determination were high in the results of linear regression analysis of depression and anxiety by serum Ca. Therefore the serum Ca concentration could be a good marker to predict depression or anxiety relatively well. The continuous high Ca intake could decrease the probability of developing depression or anxiety and mitigate their symptoms because serum Ca concentration increased, while the state of depression and anxiety decreased with the increased Ca intake.

• Journal of Plant Biology
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• v.30 no.3
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• pp.173-179
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• 1987

The effect of polyamine, Ca2+ and calmodulin on GS ($\beta$-glucan synthetase) activity was studied in Daucus carota root. The Ca2+ is shown to have no effect on the GS activity whereas the GS II activity is increased in response to increase in concentration of the Ca2+. When the protoplasts are cultured, for 4 days, the GS II activity increases as a tunction of time and reachs a maximum after 3 days at a time when the network of cellulose microfibrils is known to be synthesized. The effect of the Ca2+ and 1mM spermine on the GS II activity turns out to be synergistic, especially more synergistic at lower concentration of the Ca2+. The GS II activity seems to be enhanced by the Ca2+. The GS II activity in the protoplast treated by the calcium channel blocker, verapamil, turns out to be lower than that of the control. Cumulative results suggest that the Ca2+ stimulates the cell wall regeneration via enhancement of the GS II activity responsible for synthesizing the cell wall component throught synergistic effect with spermine.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.783-796
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• 1997

The relaxation induced by stimulation of the inhibitory non-adrenergic, non-cholinergic (iNANC) nerve is mediated by the release of iNANC neurotransmitters such as nitric oxide (NO), vasoactive intestinal peptide (VIP) and adenosine triphosphate (ATP). The mechanisms of NO, VIP or ATP-induced relaxation have been partly determined in previous studies, but the detailed mechanism remains unknown. We tried to identify the nature of iNANC neurotransmitters in the smooth muscle of guinea pig ileum and to determine the mechanism of the inhibitory effect of nitric oxide. We measured the effect of NO-donors VIP and ATP on the intracellular $Ca^{2+}$ concentration$([Ca^{2+}]_i)$, by means of a fluorescence dye(fura 2) and tension simultaneously in the isolated guinea pig ileal smooth muscle. Following are the results obtained. 1. Sodium nitroprusside $(SNP:10^{-5}\;M)$ or S -nitro-N-acetyl-penicillamine $(SNP:10^{-5}\;M)$ decreased resting $[Ca^{2+}]_i$ I and tension of muscle. SNP or SNAP also inhibited rhythmic oscillation of $[Ca^{2+}]_i$ and tension. In 40mM $K^+$ solution or carbachol ($(CCh:10^{-6}\;M)$-induced precontracted muscle, SNP decreased muscle tension. VIP did not change $[Ca^{2+}]_i$ and tension in the resting or precontracted muscle, but ATP increased resting $[Ca^{2+}]_i$ and tension in the resting muscle. 2. 1H-[1,2,4]oxadiazol(4,3-a)quinoxalin-1-one $(ODQ:1\;{\mu}M)$, a specific inhibitor of soluble guanylate cyclase, limited the inhibitory effect of SNP 3. Glibenclamide $(10\;{\mu}M)$, a blocker of $K_{ATP}$ channel, and 4-aminopyridine (4-AP:5 mM), a blocker of delayed rectifier K channel, apamin $(0.1\;{\mu}M)$, a blocker of small conductance $K_{Ca}$ channel had no effect on the inhibitory effect of SNP. Iberiotoxin $(0.1\;{\mu}M)$, a blocker of large conductance $K_{Ca}$ channel, significantly increased the resting $[Ca^{2+}]_i$, and tension, and limited the inhibitory effect of SNP. 4. Nifedipine $(1\;{\mu}M)$ or elimination of external $Ca^{2+}$ decreased not only resting $[Ca^{2+}]_i$ and tension but also oscillation of $[Ca^{2+}]_i$ and tension. Ryanodine $(5\;{\mu}M)$ and cyclopiazonic acid $(10\;{\mu}M)$ decreased oscillation of $[Ca^{2+}]_i$ and tension. 5. SNP decreased $Ca^{2+}$ sensitivity of contractile protein. In conclusion, these results suggest that 1) NO is an inhibitory neurotransmitter in the guinea pig ileum, 2) the inhibitory effect of SNP on the $[Ca^{2+}]_i$ and tension of the muscle is due to a decrease in $[Ca^{2+}]_i$ by activation of the large conductance $K_{Ca}$ channel and a decrease in the sensitivity of contractile elements to $Ca^{2+}$ through activation of G-kinase.