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Nitric Oxide Mediates Root K+/Na+ Balance in a Mangrove Plant, Kandelia obovata, by Enhancing the Expression of AKT1-Type K+ Channel and Na+/H+ Antiporter under High Salinity  [PDF]
Juan Chen, Duan-Ye Xiong, Wen-Hua Wang, Wen-Jun Hu, Martin Simon, Qiang Xiao, Juan Chen, Ting-Wu Liu, Xiang Liu, Hai-Lei Zheng
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071543
Abstract: It is well known that nitric oxide (NO) enhances salt tolerance of glycophytes. However, the effect of NO on modulating ionic balance in halophytes is not very clear. This study focuses on the role of NO in mediating K+/Na+ balance in a mangrove species, Kandelia obovata Sheue, Liu and Yong. We first analyzed the effects of sodium nitroprusside (SNP), an NO donor, on ion content and ion flux in the roots of K. obovata under high salinity. The results showed that 100 μM SNP significantly increased K+ content and Na+ efflux, but decreased Na+ content and K+ efflux. These effects of NO were reversed by specific NO synthesis inhibitor and scavenger, which confirmed the role of NO in retaining K+ and reducing Na+ in K. obovata roots. Using western-blot analysis, we found that NO increased the protein expression of plasma membrane (PM) H+-ATPase and vacuolar Na+/H+ antiporter, which were crucial proteins for ionic balance. To further clarify the molecular mechanism of NO-modulated K+/Na+ balance, partial cDNA fragments of inward-rectifying K+ channel, PM Na+/H+ antiporter, PM H+-ATPase, vacuolar Na+/H+ antiporter and vacuolar H+-ATPase subunit c were isolated. Results of quantitative real-time PCR showed that NO increased the relative expression levels of these genes, while this increase was blocked by NO synthesis inhibitors and scavenger. Above results indicate that NO greatly contribute to K+/Na+ balance in high salinity-treated K. obovata roots, by activating AKT1-type K+ channel and Na+/H+ antiporter, which are the critical components in K+/Na+ transport system.
An assessment method of Kandelia obovata population biomass

JIN Chuan,WANG Jinwang,ZHENG Jian,CHEN Qiuxi,LI Junqing,LU Xiang,

生态学报 , 2012,
Abstract: Mangroves are the unique intertidal plant formations growing in sheltered tropical and subtropical coastal areas.The past decade,many measures were undertaken for mangrove forestation in the Aojiang Estuary,Zhejiang Province,with 47 hm2 of existing Kandelia obovata forest.The present experiment was conducted to assess the population biomass of K.obovata in Aojiang Estuary.Mathematical methods that use easily measured variables to predict difficult-to-measure variables are important to mangrove managers.As a result,standard plant methods and allometric equations have been developed for several decades to estimate mangrove biomass.Single-stemed mangrove production was usually estimated by allometry between biomass and stem diameter at breast height.Because mangroves are usually dwarf forests in higher latitude sites,and moreover,the crown bases and multi-stems of dominant individuals may begin within a few decimeters of ground level,estimates of community production that depend on allometry based on single-stemed mangrove may not be accurate.Here,we develop allometric relations to predict total biomass and individual components of biomass(e.g.,leaves,stemts,roots and butts) of K.obovata,a multi-stemmed mangrove,in the Aojiang Estuary,Zhejiang province.This procedure treated each stem as a discrete tree that shared a proportion of the butt and other elements common to all stems.Linear log-log relationships were obtained between biomass and stem diameter at one-tenth of the stem length nearly the ground.Population biomass of artificial K.obovata forest in Aojiang Estuary was calculated according to the function model.We compared the difference on population biomass of K.obovata in different regions of China.The results showed that K.obovata biomass(W) correlated to the stem diameter(D) at a significance level(P < 0.001).The function model between plant biomass(leaf,WL;stem,WS;Root and butt,WB;and total,WT) and stem diameter(D) was as follows: WL=0.187D1.855(R2 =0.612,P < 0.0001);WS=0.267D1.906(R2 =0.821,P < 0.0001);WB=4.6D1.136(R2 =0.644,P < 0.0001);WT=3.614D1.446(R2 =0.801,P < 0.0001).The regression relationship between K.obovata aboveground biomass and stand age and latitude was significant in different regions of China,that is,lg(aboveground biomass)=3.123 + 0.84lg(stand age)-2.019lg(latitude)(R2 =0.431,F2,11=4.161,P =0.045).Population biomass of K.obovata increased with increased stand age,while trend to decrease with increased latitude.Population biomass of 3-,5-and 10-year-old K.obovata forest in Aojiang Estuary was estimated at 7.13,11.32 and 24.35 t/hm2,respectively.The 5-year-old population biomass in this experiment was only of 18% compared with the same age population of K.obovata grown in natural wetlands in Zhanjiang,Guangdong province.However,the biomass of 3-year-old population grown in artificial wetlands in Shenzhen was only 9.3% of the same age population biomass in this experiment.In addition,the regression relationship between pop
秋茄(Kandelia obovata)和无瓣海桑(Sonneratia apetala)红树人工林消波效应量化研究

CHEN Yu-Jun,LIAO Bao-Wen,HUANG Bo,ZHANG Qiao-Min,XU Da-Ping,CHEN Yuan-Hai,LIN Wei-Hai,LI Mei,
,廖宝文,黄 勃,张乔民,徐大平,陈元海,林卫海,李 玫

海洋与湖沼 , 2011,
Abstract: Attenuation effect of artificial mangrove Sonneratia apetala and Kandelia obovata on waves was studied quantitatively through field monitoring at Sanjiang Bay, Dongzhai Harbor, Hainan. The results showed that bare mudflat could only attenuate waves slightly, with 1/10 wave height, 1/3 wave height and mean wave height reduced by 2.9%, 4.4% and 5.8% respectively after the waves traveled 50m across the mudflat. Significant attenuation effect on waves could be seen of both artificial mangrove forests. In general, 1/10 wave height, 1/3 wave height and mean wave height were reduced by 46.3%, 46.4% and 46.1% respectively after the waves traveled 50m across artificial K. obovata forest stand, and the same indexes were reduced by 30.1%, 29.6% and 28.8% respectively on artificial S. apetala forest stand. Larger section area of mangrove forest stand turned to result in higher wave attenuation rate. At shallow water area, attenuation rate of mangrove forest decreased as the water grew deeper. While at the same water depth, attenuation rate of mangrove increased as wave height grew higher. Attenuation rate of mangrove on waves kept a nonlinearly positive relationship with travel distance of the waves. With the extension of waves across mangrove forest, wave height tended to be reduced continually, while the decline rate became less significant gradually.
镉胁迫下铵态氮对红树植物秋茄(Kandelia obovata)生理生态特征的影响
Effects of Ammonium Nitrogen on Physiological and Ecological Characteristics of Kandelia obovata under Cadmium Stress

李荣玉, 邱国玉, 沈小雪, 柴民伟
LI Rong-Yu
, QIU Guo-Yu, SHEN Xiao-Xue, CHAI Min-Wei

植物研究 , 2018, DOI: 10.7525/j.issn.1673-5102.2018.05.003
Abstract: 城市红树林湿地面临重金属污染和营养元素过量输入的环境问题。其中,镉(Cd)污染具有较高的生态风险,而铵态氮(NH4+-N)是红树林湿地沉积物中氮素的主要赋存形态。本论文采用盆栽实验研究了镉(Cd)胁迫下铵态氮(NH4+-N)对红树植物秋茄(Kandelia obovata)生理生态特征的影响,包括生物量、叶光合参数(净光合速率Pn,气孔导度Gs,胞间CO2浓度Ci和蒸腾速率E)、叶丙二醛(MDA)和可溶性糖含量以及根系活力。结果表明:(1)在单Cd胁迫下,秋茄生物量和蒸腾速率(E)显著降低,但根系活力在较高的单Cd胁迫下显著增加;(2)Cd胁迫下,低浓度NH4+-N显著增加秋茄根生物量,但对地上生物量(Cd3处理的叶和Cd1处理的茎除外)和光合作用(Pn、Gs和E)的促进作用不显著;高浓度NH4+-N显著抑制了生物量和光合作用(Pn、Gs和E);(3)在Cd1处理下,根系活力随NH4+-N胁迫的增强呈先升高后降低的趋势;在Cd2和Cd3处理下,NH4+-N显著降低了根系活力;(4)Cd胁迫下,低浓度NH4+-N对叶MDA(表征氧化损伤)和叶可溶性糖含量(表征渗透调节)的抑制不显著,高浓度NH4+-N显著降低了MDA和可溶性糖的含量。因此,较低浓度的NH4+-N能够缓解Cd对秋茄地下根的毒害,对地上部分的缓解作用有限;高浓度NH4+-N会与Cd产生协同的复合胁迫,加重对秋茄的毒害。
Thiol Reactive Probes and Chemosensors  [PDF]
Hanjing Peng,Weixuan Chen,Yunfeng Cheng,Lovemore Hakuna,Robert Strongin,Binghe Wang
Sensors , 2012, DOI: 10.3390/s121115907
Abstract: Thiols are important molecules in the environment and in biological processes. Cysteine (Cys), homocysteine (Hcy), glutathione (GSH) and hydrogen sulfide (H2S) play critical roles in a variety of physiological and pathological processes. The selective detection of thiols using reaction-based probes and sensors is very important in basic research and in disease diagnosis. This review focuses on the design of fluorescent and colorimetric probes and sensors for thiol detection. Thiol detection methods include probes and labeling agents based on nucleophilic addition and substitution, Michael addition, disulfide bond or Se-N bond cleavage, metal-sulfur interactions and more. Probes for H2S are based on nucleophilic cyclization, reduction and metal sulfide formation. Thiol probe and chemosensor design strategies and mechanism of action are discussed in this review.
Thiol-Disulfide Homeostasis in Patients with Panic Disorder  [PDF]
Burak Kulaksizoglu, Sibel Kulaksizoglu
International Journal of Clinical Medicine (IJCM) , 2017, DOI: 10.4236/ijcm.2017.81004
Abstract: Objective: To determine serum thiol/disulfide homeostasis in panic disorder (PD). Methods: Serum native thiol, total thiol, and disulfide levels were measured in the patients with 40 PD patients and 40 healthy subjects. Serum native thiol, total thiol, and disulfide levels were measured with a novel colorimetric, automated method. The thiol-disulfide ratio was also calculated. Results: The native thiol (p < 0.001) and total thiol (p < 0.001) levels, and the native thiol/total thiol (p < 0.001) ratio were significantly lower, whereas disulfide/native thiol (p < 0.001) and disulfide/total thiol (p < 0.001) ratio significantly increased in the PD patient group compared to the control group. The cut-off value was 92.26, 3.83 and 3.56 for native thiol/total thiol, disulfide/native thiol and disulfide/total thiol respectively. Conclusion: This is the first study in the literature to evaluate thiol-disulfide homeostasis in patients with PD. Our results suggest that the disulfide/thiol ratio is significantly greater in panic disorder patients.

MA Li,YANG Sheng-Chang,

水生生物学报 , 2011,
Abstract: 为探讨铝对秋茄幼苗生理特性的影响, 实验研究了不同浓度铝盐(0—100 mmol/L AlCl3)处理后秋茄的各种生理反应, 对幼苗的生长、净光合效率、膜脂过氧化作用、游离脯氨酸含量等生理指标与胁迫程度及时间的关系作了对比研究, 特别分析了高浓度(25—100 mmol/L Al3+)胁迫下, 秋茄叶片和根部活性氧清除系统保护酶活性的变化趋势。研究发现, 在10 mmol/L 浓度以下, 秋茄在生理特性上表现出对铝胁迫的最大适应性, 能维持正常生命生长过程。当浓度增加至25—100 mmol/L, 秋茄的生理反应较为敏感, 膜脂过氧化加重, MDA含量及保护酶活性随铝浓度增加的变化趋势与其在海莲中的表现基本相似。高浓度铝胁迫的极端环境使植物体内产生过量的活性氧自由基, 诱导了细胞膜系统的氧化损伤, 最终导致秋茄植株衰老甚至死亡。抗氧化保护酶系统SOD、CAT、POD的协同作用, 在一定时间内可以维持细胞内活性氧代谢平衡; 特别是POD被激活的程度最大, 且持续时间最长, 可以考虑作为秋茄幼苗抗铝胁迫的生理标志。秋茄叶片和根部的游离脯氨酸含量在25和100 mmol/L Al3+ 胁迫下均显著增加。
gao-yong理性湍流方程  [PDF]
推进技术 , 2010,
Abstract: 对近十年来gao-yong理性湍流方程的研究进行综述,给出矢量形式的可压湍流封闭方程组的推导过程。侧偏统计平均保留了湍流脉动量的一阶统计信息,在引入加权漂移速度对称性及正交各向异性后,导出了漂移流的连续方程、动量方程及机械能方程,最后依据湍流物理的唯象论,使用动量传输链概念模化封闭了整个方程组。方程组不含任何经验系数,不使用壁面函数,保留了ns方程的均化的非线性特性。其级数形式的能量方程与非线性现象多尺度层次现象相对应,具备了描述湍流统计平均流动及拟序结构流动的双重功能。已进行了大量算例验证,验证结果证明了gao-yong湍流方程对广泛范围的复杂湍流问题的适定性。
Selenium Modulates Growth and Thiol Metabolism in Wheat (Triticum aestivum L.) during Arsenic Stress  [PDF]
Srijita Ghosh, Asok K. Biswas
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.83026
Abstract: Arsenic affects plants by disrupting their growth and metabolism while selenium, an essential micronutrient has beneficial role in stress tolerance. Owing to the antioxidative capacity of selenium, it can counteract detrimental effects of arsenic induced stress in plants. The interactive influence of arsenate and selenate on the growth, arsenic and selenium accumulation, activities of non-enzymatic and enzymatic antioxidants, levels of ascorbate, α-tocopherol, total glutathione and activities of glutathione regulatory enzymes along with characterization and quantification of phytochelatins in growing wheat (Triticum aestivum L.) seedlings were investigated. Rate of arsenic accumulation was increased in arsenate treated seedlings while in seedlings treated jointly with arsenate and selenate, arsenic accumulation decreased. Arsenate stress resulted decrease in ascorbate and total glutathione contents, activities of the glutathione metabolism enzymes while significantly increased the levels of α-tocopherol and phytochelatins (PC2 and PC4), along with activities of ascorbate peroxidase and ascorbic acid oxidase in the test seedlings. The effects were more pronounced in roots than in shoots. Joint application of arsenate along with selenate was able to overcome the adverse effects caused by arsenic alone to variable extents by exhibiting significant alterations of all parameters tested, imparting better growth and thiol metabolism in the test seedlings. Our results conclude that application of selenium fertilizer in arsenic contaminated soil might be favourable to improve growth and defense ability in wheat against arsenic toxicity.
Protein Thiol Modifications Visualized In Vivo  [PDF]
Lars I. Leichert,Ursula Jakob
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0020333
Abstract: Thiol-disulfide interconversions play a crucial role in the chemistry of biological systems. They participate in the major systems that control the cellular redox potential and prevent oxidative damage. In addition, thiol-disulfide exchange reactions serve as molecular switches in a growing number of redox-regulated proteins. We developed a differential thiol-trapping technique combined with two-dimensional gel analysis, which in combination with genetic studies, allowed us to obtain a snapshot of the in vivo thiol status of cellular proteins. We determined the redox potential of protein thiols in vivo, identified and dissected the in vivo substrate proteins of the major cellular thiol-disulfide oxidoreductases, and discovered proteins that undergo thiol modifications during oxidative stress. Under normal growth conditions most cytosolic proteins had reduced cysteines, confirming existing dogmas. Among the few partly oxidized cytosolic proteins that we detected were proteins that are known to form disulfide bond intermediates transiently during their catalytic cycle (e.g., dihydrolipoyl transacetylase and lipoamide dehydrogenase). Most proteins with highly oxidized thiols were periplasmic proteins and were found to be in vivo substrates of the disulfide-bond-forming protein DsbA. We discovered a substantial number of redox-sensitive cytoplasmic proteins, whose thiol groups were significantly oxidized in strains lacking thioredoxin A. These included detoxifying enzymes as well as many metabolic enzymes with active-site cysteines that were not known to be substrates for thioredoxin. H2O2-induced oxidative stress resulted in the specific oxidation of thiols of proteins involved in detoxification of H2O2 and of enzymes of cofactor and amino acid biosynthesis pathways such as thiolperoxidase, GTP-cyclohydrolase I, and the cobalamin-independent methionine synthase MetE. Remarkably, a number of these proteins were previously or are now shown to be redox regulated.
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