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Luan S, Gao Y, Liang X, Zhang L, Yin L, He C, Liu S, Yin Z, Yue G, Zou Y, Li L, Song X, Lv C, Zhang W, Jing B. Synthesis and structure-activity relationship of lipo-diterpenoid alkaloids with potential target of topoisomerase IIα for breast cancer treatment. Bioorg Chem 2021; 109:104699. [PMID: 33611138 DOI: 10.1016/j.bioorg.2021.104699] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/24/2021] [Accepted: 01/30/2021] [Indexed: 12/24/2022]
Abstract
Aconitine linoleate (11) isolated from the Aconitum sinchiangense W. T. Wang exhibited significant anti-tumor activity. Based on this, a series of novel lipo-diterpenoid alkaloids were synthesized and evaluated for their anticancer activities against MCF-7 and MCF-7/ADR cell lines. Seventeen compounds, including 18-20, 22, 24-32, 36, 39, 41-42 possessed higher anti-proliferative activities (IC50 < 20 μM) against MCF-7 cell lines, which were better than the reference drug etoposide (IC50 = 18.01 ± 1.64 μM), among which compound 24 (IC50 = 4.00 ± 0.30 μM) was found to be the most potent derivative, being 4.5-fold more active than etoposide. Meanwhile, eighteen compounds, including 18-22, 24, 26-32, 36, 38-39, 41-42 presented excellent activities (IC50 < 20 μM) against MCF-7/ADR cell lines, better than etoposide (IC50 = 35.48 ± 0.29 μM) and doxorubicin (IC50 = 67.61 ± 6.5 μM). The most potent compound (19) was 13.5- and 25.7-fold more active than etoposide and doxorubicin against MCF-7/ADR cell lines, respectively. The structure-activity relationship (SAR) studies indicated that the 3-OH, 8-lipo, 14-benzene ring, and nitrogen atom with proper alkaline are crucial elements for anti-proliferative activity of target lipo-diterpenoid compounds. The proper length, the double bonds or di-fluoro-substituted at C-8 fatty acid chain, the para-donating electron group on 14-benzene group, and 13-OH are all favorable for the enhancement of anti-proliferative activities. In conclusion, the introduction of the 8-lipo group into aconitine leads to significant increase of anti-proliferative activity against MCF-7 and MCF-7/ADR cells, which suggests these kinds of lipo-alkaloids are powerful and promising antitumor compounds for breast cancer, especially for drug-resistant breast cancer.
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Affiliation(s)
- Shangxian Luan
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Yingying Gao
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Xiaoxia Liang
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China.
| | - Li Zhang
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Lizi Yin
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Changliang He
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Shixi Liu
- School of Chemical Science and Technology, Yunnan University, Kunming, PR China
| | - Zhongqiong Yin
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Guizhou Yue
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Yuanfeng Zou
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Lixia Li
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Xu Song
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Cheng Lv
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Wei Zhang
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Bo Jing
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
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Wu Q, Er-Bu A, Liang X, Luan S, He C, Yin L, Yin Z, Zou Y, Li L, Song X. Determination of the main naphthoquinones in Onosma hookeri Clarke. var. longiforum Duthie and its optimization of the ultrasound-assisted extraction using response surface methodology. J Food Sci 2020; 86:357-365. [PMID: 32984979 DOI: 10.1111/1750-3841.15460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/13/2020] [Accepted: 08/26/2020] [Indexed: 11/28/2022]
Abstract
In this study, besides isovaleryl shikonin, another shikonin derivative, tigloylshikonin, was also isolated from the roots of Onosma hookeri Clarke. var. longiforum Duthie as a main naphthoquinone constituent for the first time. Then optimization of the ultrasonic-assisted extraction was done by Box-Behnken design-response surface methodology on the basis of single-factor experiments. The optimized conditions were 72% (v/v) ethanol and the material to solution ratio was 1:37(g/mL) at 52 °C for 77 min. Under these conditions, the extraction yield of ethanol extract was 36.74 ± 0.32%, the contents of isovaleryl shikonin and tigloylshikonin reached 0.094 ± 0.003% and 0.223 ± 0.006%, respectively. Notably, in that optimized condition, the yield of isovaleryl shikonin increased by approximately 7.64-fold than the previous report. In the in vitro antioxidant activity assay, the optimal ethanol extract exhibited similar 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity as butylated hydroxy toluene (BHT), but slightly weaker 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) scavenging activity and total antioxidant capacity than that of BHT. However, the active polar fraction, the ethyl acetate fraction, which is enriched with naphthoquinone constituents, performs as a better antioxidant agent than BHT. Therefore, both of them could be considered as a naturally sourced antioxidants compared to commercially available synthetic drugs. PRACTICAL APPLICATION: Onosma hookeri Clarke. var. longiforum Duthie, a traditional Chinese medicine and food item, has been in use since a long time. A systematic determination of the main naphthoquinones, and antioxidant capacity of the naphthoquinones-enriched ethanol extract and different polar fractions, was carried out in the present study. The results may provide theoretical basis for the claim that naphthoquinones-enriched ethanol extract and ethyl acetate fraction from the roots of Onosma hookeri Clarke. var. longiforum Duthie could be used as potential natural antioxidants in the pharmaceutical, food, and cosmetic industries.
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Affiliation(s)
- Qiang Wu
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Aga Er-Bu
- Medical College, Tibet Univ., Lasa, 850000, P. R. China
| | - Xiaoxia Liang
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Shangxian Luan
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Changliang He
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Lizi Yin
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Zhongqiong Yin
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Yuanfeng Zou
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Lixia Li
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
| | - Xu Song
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural Univ., Chengdu, 611130, P. R. China
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Wu Q, Er‐bu A, Liang X, Luan S, Wang Y, Yin Z, He C, Yin L, Zou Y, Li L, Song X. Evaluation of antioxidant and anticancer activities of naphthoquinones-enriched ethanol extracts from the roots of Onosma hookeri Clarke. var. longiforum Duthie. Food Sci Nutr 2020; 8:4320-4329. [PMID: 32884712 PMCID: PMC7455948 DOI: 10.1002/fsn3.1729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/08/2020] [Accepted: 06/02/2020] [Indexed: 11/30/2022] Open
Abstract
In this study, the optimal naphthoquinones-enriched ethanol extract from the roots of Onosma hookeri Clarke. var. longiforum Duthie (OHC-LD) was obtained under an optimal condition (69% ethanol, material to solution ratio of 27:1 at 60℃ for 59 min) by the ultrasound-assisted extraction, according to four-variable three-level Box-Behnken design-response surface methodology. The experimental yield of ethanol extract was 42.08 ± 0.65%, and the contents of naphthoquinones reached to 1.07 ± 0.004%. The optimal extract exhibited similar scavenging activity against ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid) radical as BHT(butylated hydroxytoluene) at 1,250 µg/ml, and better DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity than BHT at 250 µg/ml. However, the optimal ethanol extract was not sensitive to MCF-7 cell line ( IC50 of 321.849 µg/ml). The results revealed the naphthoquinones-enriched ethanol extract from the roots of OHC-LD had could be used as a potential natural antioxidant.
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Affiliation(s)
- Qiang Wu
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Aga Er‐bu
- Medical collegeTibet UniversityLasaP. R. China
| | - Xiaoxia Liang
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Shangxian Luan
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Yue Wang
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Zhongqiong Yin
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Changliang He
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Lizi Yin
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Yuanfeng Zou
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Lixia Li
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
| | - Xu Song
- Natural Medicine Research CenterCollege of veterinary medicineSichuan Agricultural UniversityChengduP. R. China
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Liang X, Wu Q, Luan S, Yin Z, He C, Yin L, Zou Y, Yuan Z, Li L, Song X, He M, Lv C, Zhang W. A comprehensive review of topoisomerase inhibitors as anticancer agents in the past decade. Eur J Med Chem 2019; 171:129-168. [PMID: 30917303 DOI: 10.1016/j.ejmech.2019.03.034] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/14/2019] [Accepted: 03/14/2019] [Indexed: 01/28/2023]
Abstract
The topoisomerase enzymes play an important role in DNA metabolism, and searching for enzyme inhibitors is an important target in the search for new anticancer drugs. Discovery of new anticancer chemotherapeutical capable of inhibiting topoisomerase enzymes is highlighted in anticancer research. Therefore, biologists, organic chemists and medicinal chemists all around the world have been identifying, designing, synthesizing and evaluating a variety of novel bioactive molecules targeting topoisomerase. This review summarizes types of topoisomerase inhibitors in the past decade, and divides them into nine classes by structural characteristics, including N-heterocycles compounds, quinone derivatives, flavonoids derivatives, coumarin derivatives, lignan derivatives, polyphenol derivatives, diterpenes derivatives, fatty acids derivatives, and metal complexes. Then we discussed the application prospect and development of these anticancer compounds, as well as concluded parts of their structural-activity relationships. We believe this review would be invaluable in helping to further search potential topoisomerase inhibition as antitumor agent in clinical usage.
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Affiliation(s)
- Xiaoxia Liang
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China.
| | - Qiang Wu
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Shangxian Luan
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Zhongqiong Yin
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Changliang He
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Lizi Yin
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Yuanfeng Zou
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Zhixiang Yuan
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Lixia Li
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Xu Song
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Min He
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Cheng Lv
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Wei Zhang
- Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China
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Liang X, Luan S, Yin Z, He M, He C, Yin L, Zou Y, Yuan Z, Li L, Song X, Lv C, Zhang W. Recent advances in the medical use of silver complex. Eur J Med Chem 2018; 157:62-80. [DOI: 10.1016/j.ejmech.2018.07.057] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/16/2018] [Accepted: 07/25/2018] [Indexed: 11/28/2022]
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Liang X, Gao Y, Luan S. Two decades of advances in diterpenoid alkaloids with cytotoxicity activities. RSC Adv 2018; 8:23937-23946. [PMID: 35540251 PMCID: PMC9081856 DOI: 10.1039/c8ra03911a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/18/2018] [Indexed: 12/24/2022] Open
Abstract
The important pharmacological activities and structural complexity of diterpenoid alkaloids have long stimulated strong scientific interest; some of these naturally abundant compounds have been reported to be highly promising for treating cancer.
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Affiliation(s)
- Xiaoxia Liang
- Natural Medicine Research Center
- College of Veterinary Medicine
- Sichuan Agricultural University
- Chengdu 611130
- P. R. China
| | - Yingying Gao
- Natural Medicine Research Center
- College of Veterinary Medicine
- Sichuan Agricultural University
- Chengdu 611130
- P. R. China
| | - Shangxian Luan
- Natural Medicine Research Center
- College of Veterinary Medicine
- Sichuan Agricultural University
- Chengdu 611130
- P. R. China
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Luan S, Cowles K, Murphy MR, Cardoso FC. Effect of a grain challenge on ruminal, urine, and fecal pH, apparent total-tract starch digestibility, and milk composition of Holstein and Jersey cows. J Dairy Sci 2016; 99:2190-2200. [PMID: 26774720 DOI: 10.3168/jds.2015-9671] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 12/02/2015] [Indexed: 11/19/2022]
Abstract
The effects of a grain challenge on ruminal, urine, and fecal pH, apparent total-tract starch digestibility, and milk composition were determined. Six Holstein cows, 6 rumen-cannulated Holstein cows, and 6 Jersey cows were used in a replicated 3 × 3 Latin square design balanced to measure carryover effects. Periods (10 d) were divided into 4 stages (S): S1, d 1 to 3, served as baseline with regular total mixed ration ad libitum; S2, d 4, served as restricted feeding, with cows offered 50% of the total mixed ration fed on S1 (dry matter basis); S3, d 5, a grain challenge was performed, in which cows were fed total mixed ration ad libitum and not fed (CON) or fed an addition of 10% (MG) or 20% (HG) pellet wheat-barley (1:1) top-dressed onto the total mixed ration, based on dry matter intake obtained in S1; S4, d 6 to 10, served as recovery stage with regular total mixed ration fed ad libitum. Overall, cows had a quadratic treatment effect for milk yield where CON (22.6 kg/d) and HG (23.5 kg/d) had lower milk yield than cows in MG (23.7 kg/d). Jersey cows had a quadratic treatment effect for dry matter intake where cows in CON (13.2 kg/d) and HG (12.4 kg/d) had lower dry matter intake than cows in MG (14 kg/d). Holstein cows had a linear treatment effect for dry matter intake (17.7, 18.4, and 18.6 kg/d for CON, MG, and HG, respectively). Rumen pH for the rumen-cannulated cows had a linear treatment effect (6.45, 6.35, and 6.24 for CON, MG, and HG, respectively). Cows in HG spent more time with rumen pH below 5.8 (4.33 h) than MG (2 h) or CON (2.17 h) as shown by the quadratic treatment effect. Holstein cows in HG (8.46) had lower urine pH than MG (8.51) or CON (8.54) as showed by the linear treatment effect for urine pH. Apparent total-tract starch digestibility had a tendency for a linear treatment effect on S3 (97.62 ± 1.5, 97.47 ± 1.5, and 91.84 ± 1.6%, for CON, MG, and HG, respectively). Fecal pH was associated with rumen pH depression as early as 15 h after feeding for Holstein cows. In conclusion, a grain challenge reduced urine pH in Holstein cows but not in Jersey cows. Holstein cows' health were not affected when rumen pH was depressed. A potentially useful link between rumen pH and systemic (urine) pH within 2 h after feeding was quantified in Holstein cows.
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Affiliation(s)
- S Luan
- Department of Animal Sciences, University of Illinois, Urbana 61801
| | - K Cowles
- Cargill Office Center, Minneapolis, MN 55440
| | - M R Murphy
- Department of Animal Sciences, University of Illinois, Urbana 61801
| | - F C Cardoso
- Department of Animal Sciences, University of Illinois, Urbana 61801.
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Luan S, Duersteler M, Galbraith E, Cardoso F. Effects of direct-fed Bacillus pumilus 8G-134 on feed intake, milk yield, milk composition, feed conversion, and health condition of pre- and postpartum Holstein cows. J Dairy Sci 2015; 98:6423-32. [DOI: 10.3168/jds.2015-9512] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/11/2015] [Indexed: 12/15/2022]
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Riofrio D, Zhou J, Ma L, Luan S. TU-AB-201-04: Optimizing the Number of Catheter Implants and Their Tracks for Prostate HDR Brachytherapy. Med Phys 2015. [DOI: 10.1118/1.4925542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Maierhofer T, Diekmann M, Offenborn JN, Lind C, Bauer H, Hashimoto K, S. Al-Rasheid KA, Luan S, Kudla J, Geiger D, Hedrich R. Site- and kinase-specific phosphorylation-mediated activation of SLAC1, a guard cell anion channel stimulated by abscisic acid. Sci Signal 2014; 7:ra86. [DOI: 10.1126/scisignal.2005703] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Riofrio D, Ma L, Zhou J, Luan S. TH-A-9A-06: Inverse Planning of Gamma Knife Radiosurgery Using Natural Physical Models. Med Phys 2014. [DOI: 10.1118/1.4889576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Bornstein J, McCullough K, Combe C, Bieber B, Jadoul M, Pisoni R, Mariani L, Robinson B, Saito A, Sen A, Tentori F, Guinsburg A, Marelli C, Marcelli D, Usvyat L, Maddux D, Canaud B, Kotanko P, Hwang SJ, Hsieh HM, Chen HF, Mau LW, Lin MY, Hsu CC, Yang WC, Pitcher D, Rao A, Phelps R, Canaud B, Barbieri C, Marcelli D, Bellocchio F, Bowry S, Mari F, Amato C, Gatti E, Zitt E, Hafner-Giessauf H, Wimmer B, Herr A, Horn S, Friedl C, Sprenger-Maehr H, Kramar R, Rosenkranz AR, Lhotta K, Ferris M, Marcelli D, Marelli C, Etter M, Xu X, Grassmann A, Von Gersdorff GD, Pecoits-Filho R, Sylvestre L, Kotanko P, Usvyat L, Consortium M, Dzekova-Vidimliski P, Nikolov I, Trajceska L, Selim G, Gelev S, Matevska Geshkovska N, Dimovski A, Sikole A, Suleymanlar G, Utas C, Ecder T, Ates K, Bieber B, Robinson BM, Pisoni RL, Laplante S, Liu FX, Culleton B, Tomilina N, Bikbov B, Andrusev A, Zemchenkov A, Bieber B, Robinson BM, Pisoni RL, Bikbov B, Tomilina N, Kotenko O, Andrusev A, Panaye M, Jolivot A, Lemoine S, Guebre-Egziabher F, Doret M, Juillard L, Filiopoulos V, Hadjiyannakos D, Papakostoula A, Takouli L, Biblaki D, Dounavis A, Vlassopoulos D, Bikbov B, Tomilina N, Al Wakeel J, Bieber B, Al Obaidli AA, Ahmed Almaimani Y, Al-Arrayed S, Alhelal B, Fawzy A, Robinson BM, Pisoni RL, Aucella F, Girotti G, Gesuete A, Cicchella A, Seresin C, Vinci C, Scaparrotta G, Naso A, Pilotto A, Hoffmann TR, Flusser V, Santoro LF, Almeida FA, Aucella F, Girotti G, Gesuete A, Cicchella A, Seresin C, Vinci C, Scaparrotta G, Ganugi S, Gnerre T, Russo GE, Amato M, Naso A, Pilotto A, Trigka K, Douzdampanis P, Chouchoulis K, Mpimpi A, Kaza M, Pipili C, Kyritsis I, Fourtunas C, Ortalda V, Tomei P, Ybarek T, Lupo A, Torreggiani M, Esposito V, Catucci D, Arazzi M, Colucci M, Montagna G, Semeraro L, Efficace E, Piazza V, Picardi L, Esposito C, Hekmat R, Mohebi M, Ahmadzadehhashemi S, Park J, Hwang E, Jang M, Park S, Resende LL, Dantas MA, Martins MTS, Lopes GB, Lopes AA, Engelen W, Elseviers M, Gheuens E, Colson C, Muyshondt I, Daelemans R, He Y, Chen J, Luan S, Wan Q, Cuoghi A, Bellei E, Monari E, Bergamini S, Tomasi A, Atti M, Caiazzo M, Palladino G, Bruni F, Tekce H, Ozturk S, Aktas G, Kin Tekce B, Erdem A, Uyeturk U, Ozyasar M, Taslamacioglu Duman T, Yazici M, Schaubel DE, McCullough KP, Morgenstern H, Gallagher MP, Hasegawa T, Pisoni RL, Robinson BM, Nacak H, Van Diepen M, Suttorp MM, Hoorn EJ, Rotmans JI, Dekker FW, Speyer E, Beauger D, Gentile S, Isnard Bagnis C, Caille Y, Baudelot C, Mercier S, Jacquelinet C, Briancon S, Sosorburam T, Baterdene B, Delger A, Daelemans R, Gheuens E, Engelen W, De Boeck K, Marynissen J, Bouman K, Mann M, Exner DV, Hemmelgarn BR, Hanley D, Ahmed SB. DIALYSIS. EPIDEMIOLOGY, OUTCOME RESEARCH, HEALTH SERVICES 2. Nephrol Dial Transplant 2014. [DOI: 10.1093/ndt/gfu178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Riofrio D, Sellner S, Cabal G, Keyes R, Holzscheiter M, Jaekel O, Luan S. SU-E-T-610: Impact of Variable Beam Spot Size on Treatment Time in Particle Therapy. Med Phys 2012; 39:3846. [DOI: 10.1118/1.4735699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Keyes R, Maes D, Luan S. MO-F-BRB-04: Fast Estimation of Secondary Particle Therapy Dose Using a Modified Track Repeating Method. Med Phys 2012; 39:3874. [DOI: 10.1118/1.4735817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ma L, Hu W, Luan S. SU-E-T-880: An Investigation of Kernel-Based Dynamic Dose Painting Treatment Approach. Med Phys 2011. [DOI: 10.1118/1.3612844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Riofrio D, Keyes R, Maes D, Luan S. TU-A-BRB-03: Simultaneous Optimization of Dose and LET in Proton Therapy Using Voronoi Partitions. Med Phys 2011. [DOI: 10.1118/1.3613068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Keyes R, Arnold D, Reynaud A, Luan S. SU-E-T-688: McCloud: Toward 10 Million Monte Carlo Primaries in 5 Minutes for Clinical Use. Med Phys 2011. [DOI: 10.1118/1.3612650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Keyes R, Romano C, Arnold D, Luan S. SU-GG-T-376: Medical Physics Calculations in the Cloud: A New Paradigm for Clinical Computing. Med Phys 2010. [DOI: 10.1118/1.3468773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Riofrio D, Cabal G, Keyes R, Holzscheiter M, DeMarco J, Jäkel O, Luan S. SU-GG-T-446: Minimizing Energy Changes in Particle Therapy Using Voronoi Partitions. Med Phys 2010. [DOI: 10.1118/1.3468844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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21
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Chen Z, Luan S, Riofrio D, Ma L. SU-HH-BRB-02: A Study on the Focusing Power of Dynamic Photon Painting. Med Phys 2010. [DOI: 10.1118/1.3469020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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22
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Riofrio D, Keyes R, Hecht A, Luan S, Holzscheiter M, DeMarco J, Fahimian B. SU-FF-T-160: Planning Dynamic Particle Therapy. Med Phys 2009. [DOI: 10.1118/1.3181634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Keyes RW, Luan S, Holzscheiter M. SU-FF-T-416: Antiproton Therapy: A Simplified Method to Characterize and Compare Dose From Peripheral Radiation Fields. Med Phys 2009. [DOI: 10.1118/1.3181898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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24
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Cao D, Rao M, Chen F, Ye J, Luan S, Shepard D. SU-FF-T-222: A Novel Approach to Machine Specific QA for Volumetric Modulated Arc Therapy. Med Phys 2009. [DOI: 10.1118/1.3181698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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25
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Chen F, Rao M, Ye J, Luan S, Shepard D, Cao D. MO-D-BRB-01: Study of Systemic and Random Errors On VMAT and IMRT Plan Quality and Deliver Accuracy. Med Phys 2009. [DOI: 10.1118/1.3182211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fahimian B, DeMarco J, Keyes R, Luan S, Zankl M, Holzscheiter M. WE-C-BRB-06: Antiproton Radiotherapy: Development of Physically and Biologically Optimized Monte Carlo Treatment Planning Systems for Intensity and Energy Modulated Delivery. Med Phys 2009. [DOI: 10.1118/1.3182464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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27
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Luan S, Swanson N, Chen Z, Ma L. SU-EE-A2-05: A Planning System for Dynamic Gamma Knife Radiosurgery. Med Phys 2009. [DOI: 10.1118/1.3181103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wang C, Luan S, Tang G, Chen D, Earl M, Yu C. SU-GG-T-542: Arc-Modulated Radiation Therapy (AMRT): A Novel Method for Rotational Radiation Therapy. Med Phys 2008. [DOI: 10.1118/1.2962291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Tang G, Earl M, Luan S, Wang C, Naqvi S, Yu C. TU-EE-A1-06: Comparison of Intensity-Modulated Radiation Therapy, Intensity-Modulated Arc Therapy and Arc-Modulated Radiation Therapy. Med Phys 2008. [DOI: 10.1118/1.2962610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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31
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Tang G, Earl M, Luan S, Wang C, Naqvi S, Yu C. TH-C-350-02: Is Dose Rate Variation Crucial for Single-Arc Radiation Therapy Delivery? Med Phys 2008. [DOI: 10.1118/1.2962827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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32
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Wang C, Luan S, Tang G, Chen D, Yu C. SU-GG-T-92: Dynamic Leaf Sequencing with Monitor Units Control. Med Phys 2008. [DOI: 10.1118/1.2961844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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33
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Tang G, Earl M, Luan S, Naqvi S, Yu C. Converting Multiple-Arc Intensity Modulated Arc Therapy Into a Single Arc for Efficient Delivery. Int J Radiat Oncol Biol Phys 2007. [DOI: 10.1016/j.ijrobp.2007.07.2031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Luan S, Wang C, Cao D, Chen D, Shepard D, Yu C. TH-C-AUD-01: IMAT Leaf Sequencing Using Graph Algorithms. Med Phys 2007. [DOI: 10.1118/1.2761660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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35
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Swanson N, Luan S, Li K, Ma L. TH-D-AUD-01: A Dynamic Dose Delivery Model for Gamma Knife Radiosurgery. Med Phys 2007. [DOI: 10.1118/1.2761720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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36
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Luan S, Wang C, Cao D, Chen D, D'Souza W, Yu C. SU-FF-J-102: Patient Breathing Motion Synchronized IMAT: A New Technique for Compensating Intra-Fraction Organ Motions. Med Phys 2006. [DOI: 10.1118/1.2240878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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37
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Cao D, Earl M, Luan S, Shepard D. TU-D-ValA-03: Continuous Intensity Map Optimization (CIMO): A Novel Leaf-Sequencing Algorithm. Med Phys 2006. [DOI: 10.1118/1.2241572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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38
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Luan S, Heintz P, Sorensen S, Jimenez A, Roedersheimer K, Chen D, Wong G. The Effect of Collimator Rotation on IMRT Treatment Planning. Int J Radiat Oncol Biol Phys 2005. [DOI: 10.1016/j.ijrobp.2005.07.886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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39
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Roedersheimer K, Chen DZ, Luan S, Xing L. SU-FF-T-105: The Impact of Multileaf Collimator Rotation in IMRT Planning. Med Phys 2005. [DOI: 10.1118/1.1997776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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40
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Wang C, Luan S, Chen DZ, Hu X, Yu C. SU-FF-T-97: A Generalized MLC Segmentation Algorithm for Step-And-Shoot IMRT with No Tongue-And-Groove Error. Med Phys 2005. [DOI: 10.1118/1.1997768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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41
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Abstract
A number of environmental conditions including drought, low humidity, cold and salinity subject plants to osmotic stress. A rapid plant response to such stress conditions is stomatal closure to reduce water loss from plants. From an external stress signal to stomatal closure, many molecular components constitute a signal transduction network that couples the stimulus to the response. Numerous studies have been directed to resolving the framework and molecular details of stress signalling pathways in plants. In guard cells, studies focus on the regulation of ion channels by abscisic acid (ABA), a chemical messenger for osmotic stress. Calcium, protein kinases and phosphatases, and membrane trafficking components have been shown to play a role in ABA signalling process in guard cells. Studies also implicate ABA-independent regulation of ion channels by osmotic stress. In particular, a direct osmosensing pathway for ion channel regulation in guard cells has been identified. These pathways form a complex signalling web that monitors water status in the environment and initiates responses in stomatal movements.
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Affiliation(s)
- S. Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
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Li L, Tutone AF, Drummond RS, Gardner RC, Luan S. A novel family of magnesium transport genes in Arabidopsis. Plant Cell 2001; 13:2761-75. [PMID: 11752386 PMCID: PMC139487 DOI: 10.1105/tpc.010352] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2001] [Accepted: 09/04/2001] [Indexed: 05/18/2023]
Abstract
Magnesium (Mg(2+)) is the most abundant divalent cation in plant cells and plays a critical role in many physiological processes. We describe the identification of a 10-member Arabidopsis gene family (AtMGT) encoding putative Mg(2+) transport proteins. Most members of the AtMGT family are expressed in a range of Arabidopsis tissues. One member of this family, AtMGT1, functionally complemented a bacterial mutant lacking Mg(2+) transport capability. A second member, AtMGT10, complemented a yeast mutant defective in Mg(2+) uptake and increased the cellular Mg(2+) content of starved cells threefold during a 60-min uptake period. (63)Ni tracer studies in bacteria showed that AtMGT1 has highest affinity for Mg(2+) but may also be capable of transporting several other divalent cations, including Ni(2+), Co(2+), Fe(2+), Mn(2+), and Cu(2+). However, the concentrations required for transport of these other cations are beyond normal physiological ranges. Both AtMGT1 and AtMGT10 are highly sensitive to Al(3+) inhibition, providing potential molecular targets for Al(3+) toxicity in plants. Using green fluorescence protein as a reporter, we localized AtMGT1 protein to the plasma membrane in Arabidopsis plants. We suggest that the AtMGT gene family encodes a Mg(2+) transport system in higher plants.
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Affiliation(s)
- L Li
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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43
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Abstract
Magnesium (Mg(2+)) is the most abundant divalent cation in plant cells and plays a critical role in many physiological processes. We describe the identification of a 10-member Arabidopsis gene family (AtMGT) encoding putative Mg(2+) transport proteins. Most members of the AtMGT family are expressed in a range of Arabidopsis tissues. One member of this family, AtMGT1, functionally complemented a bacterial mutant lacking Mg(2+) transport capability. A second member, AtMGT10, complemented a yeast mutant defective in Mg(2+) uptake and increased the cellular Mg(2+) content of starved cells threefold during a 60-min uptake period. (63)Ni tracer studies in bacteria showed that AtMGT1 has highest affinity for Mg(2+) but may also be capable of transporting several other divalent cations, including Ni(2+), Co(2+), Fe(2+), Mn(2+), and Cu(2+). However, the concentrations required for transport of these other cations are beyond normal physiological ranges. Both AtMGT1 and AtMGT10 are highly sensitive to Al(3+) inhibition, providing potential molecular targets for Al(3+) toxicity in plants. Using green fluorescence protein as a reporter, we localized AtMGT1 protein to the plasma membrane in Arabidopsis plants. We suggest that the AtMGT gene family encodes a Mg(2+) transport system in higher plants.
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Affiliation(s)
- L Li
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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Luan S, Kudla J, Harter K, Gruissem W, Chory J. Renaming genes and duplication of gene names in the literature. Plant Cell 2001; 13:2391-2392. [PMID: 11701876 PMCID: PMC2652722 DOI: 10.1105/tpc.131140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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45
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Abstract
Aluminum (Al) inhibits inward K(+) channels (K(in)) in both root hair and guard cells, which accounts for at least part of the Al toxicity in plants. To understand the mechanism of Al-induced K(in) inhibition, we performed patch clamp analyses on K(in) in guard cells and on KAT1 channels expressed in Xenopus oocytes. Our results show that Al inhibits plant K(in) by blocking the channels at the cytoplasmic side of the plasma membrane. In guard cells, single-channel recording revealed that Al inhibition of K(in) occurred only upon internal exposure. Using both "giant patch" recording and single-channel analyses, we found that Al reduced KAT1 open probability and changed its activation kinetics through an internal membrane-delimited mechanism. We also provide evidence that a Ca(2)+ channel-like pathway that is sensitive to antagonists verapamil and La(3)+ mediates Al entry across the plasma membrane. We conclude that Al enters plant cells through a Ca(2)+ channel-like pathway and inhibits K(+) uptake by internally blocking K(in).
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Affiliation(s)
- K Liu
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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Kim KN, Cheong YH, Gupta R, Luan S. Interaction specificity of Arabidopsis calcineurin B-like calcium sensors and their target kinases. Plant Physiol 2000; 124:1844-53. [PMID: 11115898 PMCID: PMC59879 DOI: 10.1104/pp.124.4.1844] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2000] [Revised: 09/11/2000] [Accepted: 09/28/2000] [Indexed: 05/17/2023]
Abstract
Calcium is a critical component in a number of plant signal transduction pathways. A new family of calcium sensors called calcineurin B-like proteins (AtCBLs) have been recently identified from Arabidopsis. These calcium sensors have been shown to interact with a family of protein kinases (CIPKs). Here we report that each individual member of AtCBL family specifically interacts with a subset of CIPKs and present structural basis for the interaction and for the specificity underlying these interactions. Although the C-terminal region of CIPKs is responsible for interaction with AtCBLs, the N-terminal region of CIPKs is also involved in determining the specificity of such interaction. We have also shown that all three EF-hand motifs in AtCBL members are required for the interaction with CIPKs. Several AtCBL members failed to interact with any of the CIPKs presented in this study, suggesting that these AtCBL members either have other CIPKs as targets or they target distinct proteins other than CIPKs. These results may provide structural basis for the functional specificity of CBL family of calcium sensors and their targets.
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Affiliation(s)
- K N Kim
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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Liu K, Fu H, Bei Q, Luan S. Inward potassium channel in guard cells as a target for polyamine regulation of stomatal movements. Plant Physiol 2000; 124:1315-26. [PMID: 11080307 PMCID: PMC59229 DOI: 10.1104/pp.124.3.1315] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2000] [Accepted: 08/03/2000] [Indexed: 05/18/2023]
Abstract
A number of studies show that environmental stress conditions such as drought, high salt, and air pollutants increase polyamine levels in plant cells. However, little is understood about the physiological function of elevated polyamine levels. We report here that polyamines regulate the voltage-dependent inward K(+) channel in the plasma membrane of guard cells and modulate stomatal aperture, a plant "sensor" to environmental changes. All natural polyamines, including spermidine, spermine, cadaverine, and putrescine, strongly inhibited opening and induced closure of stomata. Whole-cell patch-clamp analysis showed that intracellular application of polyamines inhibited the inward K(+) current across the plasma membrane of guard cells. Single-channel recording analysis indicated that polyamine regulation of the K(+) channel requires unknown cytoplasmic factors. In an effort to identify the target channel at the molecular level, we found that spermidine inhibited the inward K(+) current carried by KAT1 channel that was functionally expressed in a plant cell model. These findings suggest that polyamines target KAT1-like inward K(+) channels in guard cells and modulate stomatal movements, providing a link between stress conditions, polyamine levels, and stomatal regulation.
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Affiliation(s)
- K Liu
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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Huang Y, Li H, Gupta R, Morris PC, Luan S, Kieber JJ. ATMPK4, an Arabidopsis homolog of mitogen-activated protein kinase, is activated in vitro by AtMEK1 through threonine phosphorylation. Plant Physiol 2000; 122:1301-10. [PMID: 10759527 PMCID: PMC58966 DOI: 10.1104/pp.122.4.1301] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/1999] [Accepted: 11/23/1999] [Indexed: 05/18/2023]
Abstract
The modulation of mitogen-activated protein kinase (MAPK) activity regulates many intracellular signaling processes. In animal and yeast cells, MAP kinases are activated via phosphorylation by the dual-specificity kinase MEK (MAP kinase kinase). Several plant homologs of MEK and MAPK have been identified, but the biochemical events underlying the activation of plant MAPKs remain unknown. We describe the in vitro activation of an Arabidopsis homolog of MAP kinase, ATMPK4. ATMPK4 was phosphorylated in vitro by an Arabidopsis MEK homolog, AtMEK1. This phosphorylation occurred principally on threonine (Thr) residues and resulted in elevated ATMPK4 kinase activity. A second Arabidopsis MEK isoform, ATMAP2Kalpha, failed to phosphorylate ATMPK4 in vitro. Tyr dephosphorylation by the Arabidopsis Tyr-specific phosphatase AtPTP1 resulted in an almost complete loss of ATMPK4 activity. Immunoprecipitates of Arabidopsis extracts with anti-ATMPK4 antibodies displayed myelin basic protein kinase activity that was sensitive to treatment with AtPTP1. These results demonstrate that a plant MEK can phosphorylate and activate MAPK, and that Tyr phosphorylation is critical for the catalytic activity of MAPK in plants. Surprisingly, in contrast to the animal enzymes, AtMEK1 may not be a dual-specificity kinase but, rather, the required Tyr phosphorylation on ATMPK4 may result from autophosphorylation.
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Affiliation(s)
- Y Huang
- Department of Biological Sciences, Laboratory for Molecular Biology, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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Shi J, Kim KN, Ritz O, Albrecht V, Gupta R, Harter K, Luan S, Kudla J. Novel protein kinases associated with calcineurin B-like calcium sensors in Arabidopsis. Plant Cell 1999; 11:2393-405. [PMID: 10590166 PMCID: PMC144142 DOI: 10.1105/tpc.11.12.2393] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Members of the Arabidopsis calcineurin B-like Ca(2)+ binding protein (AtCBL) family are differentially regulated by stress conditions. One AtCBL plays a role in salt stress; another is implicated in response to other stress signals, including drought, cold, and wounding. In this study, we identified a group of novel protein kinases specifically associated with AtCBL-type Ca(2)+ sensors. In addition to a typical protein kinase domain, they all contain a unique C-terminal region that is both required and sufficient for interaction with the AtCBL-type but not calmodulin-type Ca(2)+ binding proteins from plants. Interactions between the kinases and AtCBLs require micromolar concentrations of Ca(2)+, suggesting that increases in cellular Ca(2)+ concentrations may trigger the formation of AtCBL-kinase complexes in vivo. Unlike most serine/threonine kinases, the AtCBL-interacting kinase efficiently uses Mn(2)+ to Mg(2)+ as a cofactor and may function as a Mn(2)+ binding protein in the cell. These findings link a new type of Ca(2)+ sensors to a group of novel protein kinases, providing the molecular basis for a unique Ca(2)+ signaling machinery in plant cells.
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Affiliation(s)
- J Shi
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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50
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Chrispeels MJ, Holuigue L, Latorre R, Luan S, Orellana A, Peña-Cortes H, Raikhel NV, Ronald PC, Trewavas A. Signal transduction networks and the biology of plant cells. Biol Res 1999; 32:35-60. [PMID: 10530340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
The development of plant transformation in the mid-1980s and of many new tools for cell biology, molecular genetics, and biochemistry has resulted in enormous progress in plant biology in the past decade. With the completion of the genome sequence of Arabidopsis thaliana just around the corner, we can expect even faster progress in the next decade. The interface between cell biology and signal transduction is emerging as a new and important field of research. In the past we thought of cell biology strictly in terms of organelles and their biogenesis and function, and researchers focused on questions such as, how do proteins enter chloroplasts? or, what is the structure of the macromolecules of the cell wall and how are these molecules secreted? Signal transduction dealt primarily with the perception of light (photomorphogenesis) or hormones and with the effect such signals have on enhancing the activity of specific genes. Now we see that the fields of cell biology and signal transduction are merging because signals pass between organelles and a single signal transduction pathway usually involves multiple organelles or cellular structures. Here are some examples to illustrate this new paradigm. How does abscisic acid (ABA) regulate stomatal closure? This pathway involves not only ABA receptors whose location is not yet known, but cation and anion channels in the plasma membrane, changes in the cytoskeleton, movement of water through water channels in the tonoplast and the plasma membrane, proteins with a farnesyl tail that can be located either in the cytosol or attached to a membrane, and probably unidentified ion channels in the tonoplast. In addition there are highly localized calcium oscillations in the cytoplasm resulting from the release of calcium stored in various compartments. The activities of all these cellular structures need to be coordinated during ABA-induced stomatal closure. For another example of the interplay between the proteins of signal transduction pathways and cytoplasmic structures, consider how plants mount defense responses against pathogens. Elicitors produced by pathogens bind to receptors on the plant plasma membrane or in the cytosol and eventually activate a large number of genes. This results in the coordination of activities at the plasma membrane (production of reactive oxygen species), in the cytoskeleton, localized calcium oscillations, and the modulation of protein kinases and protein phosphatases whose locations remain to be determined. The movement of transcription factors into the nucleus to activate the defense genes requires their release from cytosolic anchors and passage through the nuclear pore complexes of the nuclear envelope. This review does not cover all the recent progress in plant signal transduction and cell biology; it is confined to the topics that were discussed at a recent (November 1998) workshop held in Santiago at which lecturers from Chile, the USA and the UK presented recent results from their laboratories.
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Affiliation(s)
- M J Chrispeels
- Department of Biology, University of California San Diego, La Jolla 92093-0116, USA.
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