• Molecules and Cells
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• 제44권2호
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• pp.88-100
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• 2021

Anoctamin 6/TMEM16F (ANO6) is a dual-function protein with Ca2+-activated ion channel and Ca2+-activated phospholipid scramblase activities, requiring a high intracellular Ca2+ concentration (e.g., half-maximal effective Ca2+ concentration [EC50] of [Ca2+]i > 10 μM), and strong and sustained depolarization above 0 mV. Structural comparison with Anoctamin 1/TMEM16A (ANO1), a canonical Ca2+-activated chloride channel exhibiting higher Ca2+ sensitivity (EC50 of 1 μM) than ANO6, suggested that a homologous Ca2+-transferring site in the N-terminal domain (Nt) might be responsible for the differential Ca2+ sensitivity and kinetics of activation between ANO6 and ANO1. To elucidate the role of the putative Ca2+-transferring reservoir in the Nt (Nt-CaRes), we constructed an ANO6-1-6 chimera in which Nt-CaRes was replaced with the corresponding domain of ANO1. ANO6-1-6 showed higher sensitivity to Ca2+ than ANO6. However, neither the speed of activation nor the voltage-dependence differed between ANO6 and ANO6-1-6. Molecular dynamics simulation revealed a reduced Ca2+ interaction with Nt-CaRes in ANO6 than ANO6-1-6. Moreover, mutations on potentially Ca2+-interacting acidic amino acids in ANO6 Nt-CaRes resulted in reduced Ca2+ sensitivity, implying direct interactions of Ca2+ with these residues. Based on these results, we cautiously suggest that the net charge of Nt-CaRes is responsible for the difference in Ca2+ sensitivity between ANO1 and ANO6.

• 대한화학회지
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• 제39권1호
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• pp.7-13
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• 1995

$Ca^{2+}$ 이온으로 완전히 치환된 제올라이트 $X(Ca_{46}Al_{92}Si_{100}O_{384})$와 $Ca^{2+}$ 이온과 $K^+$ 이온으로 치환된 제올라이트 $X(Ca_{46}Al_{92}Si_{100}O_{384})$를 $360^{\circ}C에서2{\times}10^{-6}$ Torr의 진공하에서 탈수한 구조를 $21^{\circ}C에서$ 입방공간군 Fd3을 사용하여 단결정 X-선 회절법으로 해석하고 구조를 정밀화하였다. 탈수한 $Ca_{46}-X$의 구조는 Full-matrix 최소자승법 정밀화 계산에서 $I>3\sigma(I)인$ 166개의 독립반사를 사용하여 최종오차인자를 R_1=0.096,\;R_2=0.068$까지 정밀화 계산하였고, $Ca_{32}K_{28}-X$의 구조는 130개의 독립반사를 사용하여 R_1=0.078,\;R_2=0.056$까지 정밀화시켰다. 탈수된 $Ca_{46}-X$에서 $Ca^{2+}$ 이온은 점유율이 높은 서로 다른 두개의 자리에 위치하고 있었다. 16개의 $Ca^{2+}$ 이온은 이중 6-산소고리(D6R)의 중심에 위치하였고(자리 I; $(Ca(1)-O(3)=2.51(2)\AA)$, 30개의 $Ca^{2+}$ 이온은 큰 동공쪽으로 약 0.44 $\AA$ 들어간 자리에 위치하고 있다(Ca(2)-O_(2)=2.24(2) $\AA$, $O(2)-Ca(2)-O(2)=119(1)^{\circ}).$ 탈수한 $Ca_{32}K_{28}-X$의 구조에서 모든 $Ca^{2+}$ 이온과 $K^+$ 이온은 4개의 서로 다른 결정학적 자리에 위치하고 있었다 : 16개의 $Ca^{2+}$ 이온은 D6R의 중심에 위치하였고, 다른 16개의 $Ca^{2+}$ 이온과 16개의 $K^+$ 이온은 큰 동공에 있는 자리 II에 각각 위치하고 있었다. 이러한 $Ca^{2+}$ 이온과 $K^+$ 이온은 O(2)의 평면에서 큰 동공쪽으로 약 0.56 $\AA$과 1.54 $\AA$ 들어간 자리에 각각 위치하고 있었다. $(Ca(2)-O(2)=2.29(2)\AA$, $O(2)-Ca(2)-O(2)=119(1)^{\circ}$, $K(1)-O(2)=2.59(2)\AA$, and $O(2)-K(1)-O(2)=99.2(8)^{\circ}).$ 12개의 $K^+$ 이온은 큰 동공에 있는 자리 III에 위치하고 있었다. $(K(2)-O(4)=3.11(6)\AA$ and $O(1)-K(2)-O(1)=128(2)^{\circ}).$

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.871-884
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• 2022

Two experiments were conducted to evaluate the effects of calcium (Ca) levels in weanling pigs (Landrace × Yorkshire × Duroc). In experiment 1, one hundred and eighty weanling pigs were randomly allotted to one of the three treatments. The treatments were low (Ca 0.60% in phase 1 and 0.50% in phase 2), standard (Ca 0.72% in phase 1 and 0.66% in phase 2), and high (Ca 0.84% in phase 1 and 0.72% in phase 2). In experiment 2, hundred and forty weanling pigs were randomly assigned to one of four treatments differing in Ca levels (high and low) and sources (CaCl₂ and CaCO₃) in a 2 × 2 factorial arrangement. There were 10 pigs per replicate in both experiments, with 6 replicates in each treatment, and they were conducted in two phases (phase 1, days 0-14; phase 2, days 15-28). In experiment 1, body weight (BW), average daily gain (ADG), and growth to feed ratio (G/F) increased as the Ca level decreased (p < 0.05). P digestibility was higher in the low-Ca diet group than in the high-Ca diet group (p <0.05). In experiment 2, the final BW, ADG, and G/F increased in the CaCl₂ diet group compared with the case in the CaCO₃ diet group (p < 0.05). The digestibility of crude protein (CP), Ca, and P was higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Cl^- levels were higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). The bicarbonate (HCO_3-), base excess (BE), and electrolyte balance (EB) levels were lower in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Hematocrit increased as the Ca level decreased (p < 0.05). The HCO_3- interacted with the Ca sources and thus, affected the Ca levels (p < 0.05). Bone ash, Ca, and P were downregulated in the low-Ca diet group compared with the case in the high-Ca diet group. Overall, the low dietary Ca supplementation led to greater growth performance. Furthermore, CaCl₂ appeared to be a better Ca source than CaCO₃ because of the greater digestibility of CP, Ca, and P, and improved EB.

• Journal of Nutrition and Health
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• 제32권3호
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• pp.248-258
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• 1999

This study examined the effect of excess loading of calcium (Ca)and iron(Fe) on the bioavailability of minerals in both normal and Ca-and Fe-deficient rats. Three-week-old male rats were divided into four groups and fed experimental diets for six weeks, containing either normal (0.5%) or high(1.5%) Ca and normal (35ppm) or high (350ppm)Fe. Likewise, three-week-old male rats were first fed a Ca-and Fe-deficient diet for three weeks, and then fed one of four experimental diets for additional three weeks. In both normal and Ca-and Fe-deficient rats, ca contents of serum, liver, kidney and femur were not significantly affected by dietary Ca and Fe levels. Apparent Ca absorption(%) decreased in rats fed a high Ca diet regardless of dietary Fe levels. Magnesium(Mg) contents of serum, liver and femur significantly decreased in rats fed a high Ca diet. Fe contents of serum and liver significantly increased in rats fed a high-Fe diet, but decreased in rats fed a high Ca diet. Fe content of serum and liver significantly increased in rate fed a high-Fe diet, decreased in rats fed a high-Ca diet. Apparent Fe absorption increased in rats fed a high-Fe diet, and decreased in rats fed a high-Ca diet in Ca-and Fe-deficient rats, but dietary Ca did not seem to affect Fe absorption in normal rats. Phosphorus(P) contents of serum and femur were not significantly affected by dietary Ca and Fe levels in both normal and Ca-and Fe-deficient rats. Serum copper(Cu) decreased in rats fed a high-Fe diet, while serum zinc(Zn) decreased in rats fed a high-Ca diet in normal rats. Cu contents of liver, and Zn contents of serum and liver decreased in rats fed a high-Fe diet in Ca-and Fe-deficient rats. There results suggest that a dietary overload of Ca and Fe in both normal and Ca-and Fe-deficient rats may decrease mineral bioavailability leading to potential health problems.

• Journal of Nutrition and Health
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• 제33권2호
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• pp.147-157
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• 2000

This study examined the effects of excess intake of calcium (Ca) and iron (Fe) supplement on bone loss, nephrocalcinosis and renal function in osteoporotic model rats. Seven-week-old female rats were first fed a Ca-deficient diet for four weeks after ovariectomy operation, and then one of nine experimental diets for additional eight weeks, containing three levels of Ca, normal (0.5%) or high (1.5%) or excess (2.5%) and three levels of Fe, normal (35ppm) or high (210ppm) or excess (350ppm). The osteoporotic model rats showed a remarkable increase in body weight, serum alkaline phosphatase (ALP) and decrease in breaking force, Ca, P, Mg contents of femur. Serum Ca concentration was not significantly affected by dietary Ca and Fe levles. Liver Ca content increased in rats fed a high-and excess-Ca diet. Kidney Ca content and microscopic Ca deposition remarkably increased in osteoporotic model rats compared to control group, and showed a tendency to decrease in rats fed a excess-Ca diet. Breaking force of femur increased with increasing dietary Ca levels, but Ca, P contents of femur and serum ALP were not significantly affected by dietary Ca and Fe levels. Serum total protein decreased in rats fed a excess-Ca diet, BUN increased in rats fed a excess-Ca diet, while serum uric acid and creatinine were not significantly affected by dietary Ca levels. Urinary creatinine, GFR increased in rats fed a high-and excess-Ca, diet, and GFR was highest in rats fed a excess-Ca/excess-Fe diet. These results suggest that excess intake of Ca may increase breaking force of femur, but not increase mineral contents of femur, and decrease kidney function. Furthermore, excess intake of Fe and Ca concurrently may aggravate kidney function leading to potential health problems in ovariectomized osteoporotic model rats.

• Journal of Applied Biological Chemistry
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• 제43권1호
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• pp.5-11
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• 2000

Three cDNA clones encoding rice calmodulin (CaM) isoforms (OsCaM-1, OsCaM-2, and OsCaM-3) were isolated from a rice cDNA library constructed from suspension-cultured rice cells treated with fungal elicitor. The coding regions of OsCaM-1 and O.sCaM-2 were 89% homologous at DNA Ievel, whereas the 5' and 3' untranslated regions were highly divergent. The polypeptides encoded by OsCaM-1 and OsCaM-2 was identical except two conservative substitution at position 8 and 75. The coding region of OsCaM-3 was consist of a typical conserved CaM domain and an additional C-terminal extension. The amino acid sequence of conserved CaM domain of OsCaM-3 shared only 86% identity with that OsCaM-1. The OsCaM-3 cDNA is belongs to a novel group of calmodulin gene due to its C-terminal extension of 38 amino acids, a large number of which are positively charged. The extension also contains a C-terminal CaaX-box prenylation site (CVlL). Genomic Southern analysis revealed at least six copies of CaM or CaM-related genes, suggesting that calmodulin may be represented by a small multigene family in the rice geneme. Expression of OsCaM gene was examined through Northern blot analysis. Transcript level of OsCaM-3 was increased by treatment with a fungal elicitor, whereas the OsCaM-1 and OsCaM-2 genes did not respond to the fungal elicitor. The expression of OsCaM-3 gene was remarkable inhibited in the rice cells treated with cyclosporine A, calcinurin inhibitor.

• Journal of Nutrition and Health
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• 제26권3호
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• pp.277-285
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• 1993

To investigate the effects of dietary calcium levels on the Ca metabolism in a rat model of ovariectomized osteoporosis, two studies were conducted. In Expt. I, five week-old femalc rats ovariectomized and fed a low Ca diet(0.06% Ca) for four weeks were compared with rats fed a normal (0.53% Ca) or low Ca diet under the sham-operated condition. Ovariectomized rats showed a significant increase in body weight and food intake. In rats fed the low Ca diet, a remarkable decrease was shown regardless of ovariectomy in serum Ca concentration, breaking force of bones, Ca and phopsphrus contents of bones, and apparent absorption and retention of Ca. Furthermore hte decrease of Ca contents of serum and bones in rats ovariectomized and fed the low Ca diet was similar to that in rats model of postmenopausal osteoporosis. In Expt. II, rats ovariectomized and fed on the low Ca diet for four weeks were divided into three groups, those given low Ca diet, normal Ca diet and high Ca diet(1.06%) respectively. The results indicated that supplementations of Ca at the intake level of 0.53% and 1.06% for 4 weeks tend to improve the relative Ca deficiency shown in experimental rat model of ovariectomized osteoporosis.

• Journal of Nutrition and Health
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• 제30권6호
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• pp.605-613
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• 1997

This study was to investigate interaction between dietary protein and Ca levels in Ca metabolism and renal function in osteporosis rats. Five week-old female rats were fed a low Ca diet for 4 weeks after ovariectomy operation to establish rat models of osteoporosis. The ovariectomized osteoporosis rats were divided into six groups and were fed experimental diets which contained two levels of protein, normal (20%) and high(40%) , and three levels of Ca, low (0.06%), normal (0.47%) and high(0.94%) for 4 weeks , respectively. The ovaricetmized rat model of osteoporosis showed a remarkable decrease in serum Ca concentration, fresh weight and breaking force of femur, Ca and P contents of femur, and apparent absorption and retention of Ca. The supplementations of Ca and P contents of femur, and apparent absorption and retention of Ca. The supplementations of Ca at the dietary levels of normal and high levels significantly enhanced Ca bioavailability shown in the above experimental rat models of osteoporosis, regardless of dietary protein levels ; whereas the rats which were fed the low Ca diet demonstrated rather a decrease in its bioavailability. Irrespectively of the dietary Ca levels, the rats which were fed high protein diet exhibited an increase in kidney weight, urinary Ca, volume and hydroxyproline, and glomerular filtration ratio(GFR). The results show that dietary protein and calcium levels affect the renal function and Ca metabolism independently, while the interaction between protein and calcium have not been shown.

• 약학회지
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• 제50권2호
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• pp.111-117
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• 2006

Cardiac chambers serve as mechanosensory systems during the haemodynamic or mechanical disturbances. To examine a possible role of fluid pressure (FP) in the regulatien of atrial $Ca^{2+}$ signaling we investigated the effect of FP on L-type $Ca^{2+}$ current $(I_{Ca})$ in rat ventricular myocytes using whole-cell patch-clamp technique. FP $(\sim40cm\;H_2O)$ was applied to whole area of single myocytes with electronically controlled micro-jet system. FP suppressed the magnitude of peak $I_{Ca}$ by $\cong25\%$ at 0 mV without changing voltage dependence of the current-voltage relationship. FP significantly accelerated slow component in inactivation of $I_{Ca}$, but not its fast component. Analysis of steady-state inactivation curve revealed a reduction of the number of $Ca^{2+}$ channels available for activity in the presence of FP. Dialysis of myocytes with high concentration of immobile $Ca^{2+}$ buffer partially attenuated the FP-induced suppression of $I_{Ca}$. In addition, the intracellular $Ca^{2+}$ buttering abolished the FP-induced acceleration of slow component in $I_{Ca}$ inactivation. These results indicate that FP sup-presses $Ca^{2+}$ currents, in part, by increasing cytosolic $Ca^{2+}$ concentration.

• 생물환경조절학회지
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• 제11권3호
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• pp.127-132
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• 2002

시설토양내 Na나 Cl이온의 과다집적은 직접 또는 간접적으로 작물의 생육에 장해를 준다 따라서 본 실험은 플라스틱 포트재배에서 NaCl에 의해 생육이 억제된 작물에 Ca을 토양에 시용함으로써 치유효과를 검토코자 수행되었다. 토마토(하우스 모모타로)를 공시하여 80 mM NaCl를 처리하고 Ca(NO$_3$)$_2$과 CaCl$_2$을 각각 0, 10, 20mM을 토마토 재배용 야마자키 표준양액에 첨가하여 공급하였다. NaCl집적토양에 Ca을 시용함으로써 모두 초장,생체중,건물중,착과수,과중의 생육을 촉진하였다 이러한 효과는 Ca의 농도가 높을수록 좋았고 Ca(NO$_3$)$_2$이 CaCl$_2$보다 좋았다 수량은 NaCl 집적＋Ca(NO$_3$)$_2$ 20mM 처리구에서 대조구를 제외한 여타 처리구보다 많았다. 광합성 속도는 Ca 처리구가 NaCl 처리구보다 높았으며, Ca 농도가 증가할수록 높았다. 엽록소 함량은 Ca처리구에서 대조구보다 많았으며, 새로운 잎이 오래된 잎보다 많았으나 Ca의 농도간에는 큰 차이가 없었다. Ca(NO$_3$)$_2$이나 CaCl$_2$을 처리함으로써 식물체의 Na함량은 감소하였고 N, K및 Ca함량은 증가하였다. 특히 K/Na비율이 현저하게 증가하였으나, Cl함량은 감소하였다. 이상의 결과에서 NaCl의 스트레스를 받은 작물에 Ca(NO$_3$)$_2$및 Cac12을 처리함으로써 생육이 촉진되고 수량이 증가되나 대조구보다는 저조함을 알 수 있었다.