Global CO_(2) concentration change induced by“trigger-connectors”model,especially since about 24 Ma?A preliminary hypothesis

Background,aim,and scope The tectonic uplift of the Cenozoic Tibetan Plateau has produced a chain effect,which is an excellent location for Earth system science research,and its uplift process,mechanism and environmental effects are the hot spot and frontier of the current research.The“Tibetan Plateau uplift-weathering-CO_(2) concentration-global climate change”model was put forward by Raymo and Ruddiman to interpret the Late Cenozoic climate change.However,there are still some questions suspended,such as does the weathering of the Tibetan Plateau have the ability to control the global climate?How to explain the modern-like global CO_(2) concentration starting at about 24 Ma?Here,a short space was taken to present a brainstorm about the above questions on account of existing geological pieces of evidence.Materials and methods In this paper,we integrate the formation and evolution of the Yangtze River and Pearl River,the origin and development of the Asian inland aridification-monsoon system,the Cenozoic tectonic uplift process of the Tibetan Plateau,and the westerly winds to discuss and analyze the relationship between the Cenozoic CO_(2) concentration changes and the uplift of the Tibetan Plateau and why the CO_(2) concentration similar to the present was formed at about 24 Ma.Results Similar correspondence of the surface uplift history of Xizang,other global mountains,and the declining CO_(2) concentration could support the theory Tibetan Plateau weathering inf luences CO_(2) concentration.Starting from 24 Ma,the most important character was the uplift and erosion of Xizang and Himalaya,collaborating with Ocean Iron Fertilization(OIF)together as an entity to control the atmospheric CO_(2) concentration because the great Asian rivers,Asian monsoons,and westerlies connected Xizang and surrounded seas together through materials transportation.Discussion Paleogeographic reconstructions from 40 Ma to 20 Ma illustrate that the main topographic change occurred in the Andes,Cordillera orogenic belt,and Xizang.We comprise a comprehensive set of evidence from independent data,which correspond temporally with the tipping point(about 24 Ma)of the atmospheric CO_(2) and we noticed that modern-like Asia monsoon,inland aridity,Asian great rivers,and climate zone formed at about 24 Ma and also there are tectonic activities for the Andes and Rockies.We raised the possibility that the modern-like atmospheric CO_(2) concentration at about 24 Ma was caused by the above geological factors.Here the rivers,monsoon,and westerlies are termed as“connectors”.In addition,these Asian rivers originated from Xizang,the monsoon,and inner Asian aridification are strongly a function of the uplift and growth of Xizang,thus,Xizang here is named as“trigger”.The distinct character of“trigger-connectors”model is that this not only takes the monsoon,westerlies,and the global great rivers into consideration but also expands the range which inf luences atmospheric CO_(2) concentration,from local points to a vast area since about 24 Ma,such as from Tibetan Plateau to Asia,including surrounded seas,after about 24 Ma.However,because the opening of the Late Oligocene-Early Miocene Antarctic periphery straits is highly coincident with the onset of modern-like global atmospheric CO_(2) concentration,we are forced to consider that they also had a significant impact on the reduction of atmospheric CO_(2) concentrations at this time.Conclusions“Trigger-connectors”was put forward to explain the Cenozoic CO_(2) variation,especially modern-like global CO_(2) concentration since about 24 Ma.Recommendations and perspectives Here we use the“trigger-connectors”model to explain the formation of modern-like CO_(2) concentrations starting at about 24 Ma,but there are still some problems.The most important premise for the“trigger-connectors”model is the constructed Cenozoic CO_(2) concentration record is reliable,which is the foundation of our hypothesis.In the future,potential improvements should focus on topographic reconstructions of Xizang and the global mountains.Here we have concentrated on Xizang in the considered timeslices but still,pay less attention to other global orogenic belts.Collaborations with geologist experts in those regions could provide valuable feedback to evaluate their potential role of them in CO_(2) evolution.What is more,considerable progress may be achieved with the addition and consideration of more and new geological data.

富里酸和Ca^(2+)共存对嗜酸性氧化亚铁硫杆菌介导生成次生高铁矿物的影响

为揭示富里酸和Ca^(2+)共存对嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)氧化酸性矿山废水(AMD)中的Fe^(2+)和形成次生高铁矿物的影响,分析了pH、Fe^(2+)氧化率、铁沉淀率以及次生高铁矿物矿相、基团等相关指标。结果表明,Ca^(2+)确实具有提高嗜酸性氧化亚铁硫杆菌氧化Fe^(2+)的能力。低质量浓度(0.2 g/L)的富里酸对嗜酸性氧化亚铁硫杆菌活性的提高具有促进作用,高质量浓度(0.4 g/L)的富里酸具有抑制作用,而增加Ca^(2+)反过来能够减弱高浓度富里酸对嗜酸性氧化亚铁硫杆菌的抑制作用。对形成的次生高铁矿物进行X射线衍射(XRD)和傅立叶红外光谱(FTIR)分析,结果表明高浓度富里酸促进了另一次生高铁矿物草黄铁矾的生成。

川芎嗪抑制ROCK的表达降低模拟失重大鼠血管Ca^(2+)敏感性

研究失重条件下血管平滑肌收缩性、Ca^(2+)敏感性及其调控通路RhoA-ROCK蛋白表达的变化,以及川芎嗪干预对其的影响。大鼠尾部悬吊模拟失重,在机体前、后部分别选取颈总动脉和肠系膜上动脉。在模拟失重大鼠颈总动脉中,由苯肾上腺素(PHE)或KCl诱发的血管收缩性和Ca^(2+)敏感性增强,RhoA激酶2(ROCK II)的表达、肌球蛋白磷酸酶靶亚基1(MYPT1)和肌球蛋白调节轻链(MLC)的磷酸化水平均上升,血管孵育Y-27632(ROCK特异性抑制剂)后可降低以上变化。模拟失重大鼠灌饲川芎嗪亦可降低以上变化。模拟失重后,大鼠肠系膜上动脉的收缩性和Ca^(2+)敏感性、ROCK II的表达、MYPT1和MLC的磷酸化水平降低,血管孵育Y-27632对以上变化无明显作用。模拟失重大鼠灌饲川芎嗪亦对以上变化无明显作用。结果表明,由RhoA-ROCK调控的血管平滑肌Ca^(2+)敏感性的变化可能是失重条件下机体前后部血管收缩性发生区域性重塑的关键因素。川芎嗪可抑制ROCK蛋白的表达,降低血管平滑肌升高的Ca^(2+)敏感性,从而纠正失重条件下机体前部血管收缩性的增强,但对失重条件下机体后部血管收缩性的减弱无恢复作用。

外源Ca^(2+)对玉米幼苗镉胁迫的缓解效应

本试验以玉米为研究材料,对玉米幼苗进行一定浓度的镉(20mg/L)胁迫,通过对玉米幼苗施加不同浓度的Ca^(2+)(0、2、5、8mmol/L),研究Ca^(2+)对镉胁迫下玉米幼苗的叶绿素、MDA、可溶性糖、可溶性蛋白、游离脯氨酸和POD活性6个生理生化指标的影响。结果表明:施加外源Ca^(2+)显著增加了镉胁迫下南瓜幼苗叶片中叶绿素含量(P<0.05),而MDA含量、可溶性糖含量、游离脯氨酸含量以及POD活性均显著降低(P<0.05),对可溶性蛋白的缓解作用不显著(P>0.05)。其中以5mmol/LCa^(2+)的缓解效果最好。

复合混凝剂中Ca^(2+)对高溶解态磷坑塘水混凝效果的影响

文章以Ca^(2+)改性后的AlCl_(3)和PACl作为混凝剂进行混凝实验,通过出水浊度、余铝、总磷、絮体粒径及有机物组成等分析改性后混凝剂的作用机理,探讨混凝剂中存在的Ca^(2+)对高磷坑塘水混凝效果的影响机制。浊度去除方面,低投加量下Ca^(2+)可明显降低出水浊度。当投加量为0.10 mmol/L时,PACl出水浊度下降了33.52 NTU,AlCl_(3)出水浊度下降了28.72 NTU。余铝去除方面,当AlCl_(3)作混凝剂时,Ca^(2+)可以通过增加混凝剂的电中和能力来降低出水余铝浓度。溶解态磷去除方面,Ca^(2+)与磷酸根反应或通过压缩双电层和吸附电中和作用来增加溶解态磷的去除率。当投加量为0.20 mmol/L时,Ca^(2+)浓度为0.9 mmol/L,PACl溶解态磷去除率较未改性前提高16.1%。絮体粒径方面,Ca^(2+)可以促进颗粒之间脱稳凝聚,增加絮体粒径和分形维数,AlCl_(3)在0.20 mmol/L投加量下絮体粒径增加79μm。并且Ca^(2+)的加入使AlCl_(3)生成的絮体抗剪切能力更强,但是絮体受到破坏后更不容易恢复,使PACl形成絮体强度因子和恢复因子变大。有机物去除方面,Ca^(2+)可以提高有机物的去除率。对于0.20 mmol/L投加量,Ca^(2+)为0.06 mmol/L投加量条件下AlCl_(3)改性后混凝剂荧光响应值由1100降至800。

Effects of Ca^(2+)concentrations on accumulations of mineral elements in the components of Pteroceltis tatarinowii

The bark of Pteroce/tis tatarinowii is a raw material for manufacturing XuanPaper. The effects of Ca^(2+) concentrations on the accumulation of mineral elements in the bark,leaf and root of Pteroceltis tatarinowii were studied under controlled conditions. The types ofHoagland nutrient solution with three Ca^(2+) concentrations levels (200, 400 and 600 μg·g^(-1))and a control (without Ca^(2+)) were designed to culture Pteroceltis tatarinowii. After 6 months,contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and barkwere analyzed. The results indicated that Ca accumulations content in the root, leaf and bark hadpositively relation with Ca^(2+) concentrations (200, 400, 600 μg · g^(-1)), and the order of theCa content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g^(-1) Ca^(2+) concentrations was 5.5 times as high as that of the control, and about 1.4 times ashigh as that of the root treated in 200 and 400 μg/g Ca^(2+) concentrations respectively. On thecontrary, K and Mg contents in the root, leaf and bark were negatively related to Ca^(2+)concentrations, especially in the bark, and their accumulation trend followed the order ofleaf>root>bark. K content in the bark treated with 600 μg ·g^(-1) Ca^(2+) concentrations was 39.3%of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 μg ·g^(-1)and 400 μg ·g^(-1) Ca^(2+) concentrations respectively; Mg content in the bark treated with 600μg ·g^(-1) Ca^(2+) concentrations was 23.4% of that of the control, and was 27.1% and 35.4% ofthat of the bark treated with 200 and 400 μg·g^(-1) Ca^(2+) concentrations respectively. Comparedwith the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca^(2+)concentrations and their contents were in the order: root>leaf>bark. Based on the results of thisstudy, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil.

Ca^(2+)/CaN/NFAT信号通路在肿瘤中的研究进展

肿瘤成为危害人类健康的主要原因,其发生发展与免疫炎症密切相关.Ca^(2+)/CaN/NFAT信号通路是目前已知的免疫炎症通路,可促进多种免疫细胞活化,介导免疫炎症因子释放,进而影响机体的免疫功能.目前,Ca^(2+)/CaN/NFAT信号通路在肿瘤中的存在和作用越来越受关注.多项研究表明与该通路与肿瘤发生发展密切相关.故本文从Ca^(2+)/CaN/NFAT信号通路概述、信号通路对肿瘤发生发展的影响、信号通路对肿瘤免疫炎症的作用及与信号通路相关药物在防治肿瘤中的作用四方面进行综述,以期为临床防治肿瘤提供新视角新靶点.

Ca^(2+)-ATPase参与植物耐盐性调控的研究进展

盐胁迫下细胞质Ca^(2+)浓度升高,细胞会激活Ca^(2+)调节的靶酶或者与Ca^(2+)高度亲和的受体蛋白,其中,与Ca^(2+)高度亲和的受体蛋白中,植物钙泵(Ca^(2+)-ATPase)是P型ATP酶,包含内质网Ca^(2+)-ATPases与质膜Ca^(2+)-ATPas‐es,通过主动运输将Ca^(2+)从细胞质转移到质外体或细胞器。大量研究表明,植物的耐盐性在很大程度上与其维持钙泵即Ca^(2+)-ATPase活性的能力有关。多种植物Ca^(2+)-ATPase对盐胁迫表现出敏感性,并受到外源Ca^(2+)的保护,表明外源钙处理与Ca^(2+)-ATPase活性可能在盐胁迫下的细胞内钙稳态和信号转导中起重要作用。该研究概述了植物Ca^(2+)-ATPase类型、结构与性质,亚细胞定位Ca^(2+)-ATPase及外源钙与亚细胞定位Ca^(2+)-ATPase参与植物耐盐调控研究进展,重点对质膜、液泡膜、核膜、内质网及高尔基体Ca^(2+)-ATPases参与植物耐盐调控的研究进展进行了综述,并提出展望。该研究为了解植物耐盐性生理及分子机制提供帮助,同时为作物耐盐栽培提供新思路。

外源Ca^(2+)对金线莲组培苗生长发育的影响

以金线莲组培苗为试验材料,研究添加不同浓度(0、1.5、3、6、9 mmol/L)Ca^(2+)对金线莲组培苗的气孔细胞、农艺性状、酶活性的影响。结果表明,在1.5 mmol/L Ca^(2+)环境下培养的金线莲叶片宽大、植株也相对健壮,总体长势较好,生理生化指标体现该浓度下的金线莲各类代谢活动较为旺盛,各种关键酶的活性也比较高,抗逆性能较优,6 mmol/L Ca^(2+)环境下培养的金线莲叶片较小且幼嫩,但植株丛芽多而健壮。因此,1.5 mmol/L Ca^(2+)是相对适宜金线莲组培苗生长发育的钙环境,而6 mmol/L Ca^(2+)是相对适宜金线莲长芽扩繁的钙环境。

β-细辛醚通过抑制TRPV4的表达缓解谷氨酸诱导的Ca^(2+)超载

谷氨酸处理会导致Ca^(2+)超载,瞬时受体电位香草素受体4(transient receptor potential vanilloid 4,TRPV4)在其中的作用及可能机制尚不清楚。β-细辛醚能快速透过血脑屏障,对兴奋性毒性具有较强的神经保护作用。文章以高分化的PC12细胞为研究对象,探究β-细辛醚(15、30、60μmol/L)预处理4 h,40 mmol/L谷氨酸处理实时记录对PC12细胞Ca^(2+)浓度的影响,采用钙成像技术检测Ca^(2+)浓度的变化;采用实时荧光定量聚合酶链式反应(polymerase chain reaction,PCR)、Western Blot及免疫荧光技术检测TRPV4的mRNA和蛋白的表达;采用Lipofectiamine 2000脂质体实验转染TRPV4-siRNA和pEX-3-TRPV4,观察沉默和过表达TRPV4对谷氨酸引起Ca^(2+)超载的影响。结果表明:与正常对照组相比,谷氨酸处理5 min可诱导Ca^(2+)超载,显著提高TRPV4的mRNA和蛋白的表达;与模型组相比,β-细辛醚能够剂量依赖性地降低谷氨酸诱导的Ca^(2+)超载和TRPV4的表达;沉默TRPV4抑制细胞Ca^(2+)超载;过表达TRPV4则部分逆转β-细辛醚抑制谷氨酸诱导的Ca^(2+)超载。该研究证明,谷氨酸处理PC12细胞5 min通过上调TRPV4的表达诱导Ca^(2+)超载,β-细辛醚作为TRPV4的拮抗剂,是一种潜在的抑制兴奋性毒性的药物。

活血益肾法联合西药对踝关节骨折术后血清Ca^(2+)、ALP及踝关节功能的影响

目的探讨活血益肾法联合西药对踝关节骨折术后血清Ca^(2+)、碱性磷酸酶(ALP)及踝关节功能的影响。方法选取踝关节骨折术后患者105例,随机分为试验组(n=53)和对照组(n=52)。对照组给予地塞米松治疗,试验组在对照组的基础上加用活血益肾法治疗。比较两组临床疗效、血清Ca^(2+)、ALP、踝关节功能水平变化情况、临床症状改善情况及不良反应发生情况。结果治疗后,试验组踝关节功能恢复优良率显著高于对照组;治疗后,试验组血清Ca^(2+)、ALP水平高于对照组;治疗后,两组肌力背伸、跖屈和背伸关节主动活动度、跖屈关节主动活动度水平均升高,且试验组高于对照组;治疗后,试验组临床各症状改善时间均显著低于对照组;以上组间差异均有统计学意义(P<0.05)。治疗期间,两组不良反应比较差异无统计学意义(P>0.05)。结论踝关节骨折术后应用活血益肾法联合西药效果显著,可有效改善患者血清Ca^(2+)、ALP及踝关节功能水平。

miR-361介导PI3K/Akt/Ca^(2+)通路对大鼠肥大细胞增殖情况及组胺与IL-4表达水平的影响

目的:探讨miR-361介导PI3K/AKt/Ca^(2+)通路对活化大鼠肥大细胞增殖情况及组胺与白细胞介素-4(IL-4)表达水平的影响。方法:将大鼠肥大细胞(RBL-2H3细胞)分为miR-361过表达组、miR-361抑制组、miR-361对照组和正常对照组,miR-361过表达组、miR-361抑制组、miR-361对照组细胞分别转染miR-361过表达、miR-361抑制及miR-361无义序列寡核苷酸片段,测定并比较各组细胞miR-361 mRNA、组胺、IL-4及PI3K/AKt/Ca^(2+)通路相关蛋白水平。结果:miR-361过表达组细胞miR-361 mRNA相对表达水平高于miR-361抑制组、miR-361对照组及正常对照组,差异均有统计学意义(P<0.05)。CCK-8法检测结果显示,miR-361过表达组24、48、72 h细胞增值率均低于miR-361抑制组、miR-361对照组及正常对照组,差异均有统计学意义(P<0.05)。ELISA法检测结果显示,miR-361过表达组细胞组胺和IL-4水平的表达水平低于miR-361抑制组、miR-361对照组及正常对照组,差异均有统计学意义(P<0.05)。Western印迹法检测结果显示,miR-361过表达组细胞p-AKT、AKT、p-PI3K、PI3K蛋白表达水平均高于miR-361抑制组、miR-361对照组及正常对照组,差异均有统计学意义(P<0.05)。结论:miR-361过表达可抑制大鼠肥大细胞的增殖,降低组胺与IL-4的表达水平,其作用机制可能与其能够提高PI3K/AKt/Ca^(2+)通路活性有关。

STIM1和Orai1/TRPCs在右心衰竭Ca^(2+)重塑中的作用

本文总结右心衰竭心肌细胞动作电位变化、心肌细胞内T管和内质网的改变,详细阐述了钙调神经磷酸酶(Calcineurin)-活化细胞活因子(NFAT)通路对心肌收缩力的作用。重点描述基质相互作用因子1(STIM1)和钙释放激活钙通道蛋白1(Orai1)/瞬时受体电位通道(TRPCs)通路在右心室心肌细胞兴奋收缩耦联、肥大及右心室成纤维细胞迁移增强方面的机制。

Ca^(2+)对茅苍术丛生芽诱导及生理特征的影响

为提高茅苍术组培苗品质,以信阳野生茅苍术种子获取的初代无菌试管苗为试材,采用植物组织培养试验方法,研究不同浓度Ca^(2+)对茅苍术丛生芽诱导及生理特征的影响。结果表明:Ca^(2+)浓度为1.50 mmol/L时茅苍术丛生芽增殖数最高,为16.36个;Ca^(2+)浓度为3.00 mmol/L时丛生芽总干重最高,为0.37 g;Ca^(2+)浓度为6.00 mmol/L时丛生芽总鲜重、单芽平均叶片数最高,分别为3.19 g、5.44个;Ca^(2+)浓度为12.00 mmol/L时茅苍术丛生芽的株高最高,为493.95 mm;Ca^(2+)浓度为24.00 mmol/L时叶绿素a含量、叶绿素b含量、类胡萝卜素含量、叶绿素总量和丛生芽SOD总活性最高,分别为1.54 mg/g、0.40 mg/g、0.36 mg/g、1.94 mg/g和329.36 U/g。在茅苍术组织培养过程中可根据不同需求选择相应的Ca^(2+)浓度。

Synergistic strengthening mechanism of Ca^(2+)-sodium silicate to selective separation of feldspar and quartz

Inhibitors are important for flotation separation of quartz and feldspar.In this study,a novel combined inhibitor was used to separate quartz and feldspar in near-neutral pulp.Selective inhibition of the combined inhibitor was assessed by micro-flotation experiments.And a series of detection methods were used to detect differences in the surface properties of feldspars and quartz after flotation reagents and put forward the synergistic strengthening mechanism.The outcomes were pointed out that pre-mixing combined inhibitors were more effective than the addition of Ca^(2+)and SS in sequence under the optimal proportion of 1:5.A concentrate from artificial mixed minerals that was characterized by a high quartz grade and a high recovery was acquired,and was found to be 90.70wt% and 83.70%,respectively.It was demonstrated that the combined inhibitor selectively prevented the action of the collector and feldspar from Fourier-transform infrared(FT-IR)and adsorption capacity tests.The results of X-ray photoelectron spectroscopy(XPS)indicated that Ca^(2+)directly interacts with the surface of quartz to increase the adsorption of collectors.In contrast,the chemistry property of Al on the feldspar surface was altered by combined inhibitor due to Na^(+)and Ca^(2+)taking the place of K^(+),resulting in the composite inhibitor forms a hydrophilic structure,which prevents the adsorption of the collector on the surface of feldspar by interacting with the Al active site.The combination of Ca^(2+)and SS synergically strengthens the difference of collecting property between quartz and feldspar by collector,thus achieving the effect of efficient separation.A new strategy for flotation to separate quartz from feldspar in near-neutral pulp was provided.

Uniform deposition of ultra-thin TiO_(2) film on mica substrate by atmospheric pressure chemical vapor deposition: Effect of precursor concentration

The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.

外源Ca^(2+)对两种产脲酶细菌修复Cd-As复合污染水稻土的影响

微生物诱导碳酸盐沉淀(Microbially induced carbonate precipitation,MICP)技术已被广泛应用于土壤重金属污染修复。为促进MICP过程,提高土壤修复效果,以Cd-As复合污染的水稻土为研究对象,利用巴氏八叠球菌(Octococcus pasteurii)和蜡样芽孢杆菌(Bacillus cereus)两种产脲酶细菌,分析比较了外源添加氯化钙(CaCl2)对两种菌株固定土壤中Cd、As效果的影响,并对修复后土壤理化性质、酶活性及微生物多样性的变化进行了检测。结果表明:两种菌株均能固定土壤Cd、As,其中,蜡样芽孢杆菌对土壤Cd、As的固定效果更佳,与巴氏八叠球菌处理相比,蜡样芽孢杆菌处理下土壤有效态Cd、As含量分别降低了16.7%、11.1%;添加外源Ca^(2+)后,在两种细菌处理下有效态Cd、As含量均发生显著变化,分别降低了17.3%~22.2%、16.8%~26.7%,可见Ca^(2+)的添加能有效促进MICP过程,促进对Cd、As的固定。此外,与未添加Ca^(2+)处理相比,添加Ca^(2+)后,两种细菌处理下显著提高了土壤脲酶活性(52.6%~113.3%)、蔗糖酶活性(13.1%~28.9%)、碱解氮含量(3.4%~25.5%)、速效钾含量(2.1%~34.1%)以及微生物多样性,表明外源Ca^(2+)可有效提高土壤肥力及土壤生态功能。综上,基于MICP作用,可通过添加外源Ca^(2+)来增强产脲酶细菌对Cd-As复合污染土壤的修复效果,其中,蜡样芽孢杆菌修复效果更佳。

氧糖剥夺再灌注对神经元Wnt5a/FZD2/Ca^(2+)通路的影响

目的:探讨氧糖剥夺再灌注(OGD/Rep)后神经元细胞内Wnt5a/FZD2/Ca^(2+)通路的变化。方法:采用OGD/Rep模型构建神经元细胞局部缺血/再灌注损伤,分正常组、再灌注(0、3、6、9、12、24 h)组。免疫荧光鉴定皮层神经元细胞,CCK-8法确定神经元细胞OGD时间,Western blotting检测非经典Wnt/Ca^(2+)信号通路中Wnt5a、FZD2、IP3-R和p-CaMKⅡ/CaMKⅡ蛋白的变化,免疫荧光和酶标仪检测细胞内Ca^(2+)和活性氧(ROS)的含量。结果:MAP-2免疫荧光鉴定原代皮层神经元细胞纯度较高。与正常组比较,神经元细胞OGD 3 h后细胞存活率为55.46%;与正常组比较,OGD/Rep后非经典Wnt/Ca^(2+)信号通路相关蛋白Wnt5a(3、6、9、12、24 h)、FZD2(3、6、9 h)、IP3-R(6、9、12、24 h)和p-CaMKⅡ/CaMKⅡ(6 h)的相对表达量上调(P<0.05~P<0.01);与正常组比较,OGD/Rep后神经细胞内Ca^(2+)和ROS的表达量均升高(P<0.01)。结论:神经元细胞OGD/Rep能激活Wnt5a/FZD2/Ca^(2+)信号通路。

炎症微环境作用下P38 MAPK调控Wnt/Ca^(2+)信号通路对牙周膜干细胞成骨分化的影响研究

目的探讨炎症微环境作用下P38丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)对牙周膜干细胞(periodontal ligament stem cell,PDLSC)成骨分化和Wnt/Ca^(2+)信号通路的影响。方法将人PDLSC分为对照组、TNF-α组、TNF-α+SB203580组(20μmol/L SB20358)、TNF-α+SB203580+XAV939组(20μmol/L SB20358+10μmol/L XAV939),除对照组外其余各组细胞给予10 ng/mL TNF-α模拟炎症微环境。茜素红染色检测成骨分化能力,比较各组细胞碱性磷酸酶(alkaline phosphatase,ALP)活性,RT-qPCR检测成骨关键基因Runt相关转录因子2(Runx2)、骨钙蛋白(osteocalcin,OCN)、Osterix(OSX)蛋白、骨桥蛋白(osteopontin,OPN)mRNA水平,蛋白质印迹检测P38 MAPK、β-catenin、钙调蛋白依赖性激酶Ⅱ(CaMKⅡ)、Nemo样激酶(Nemo-like kinase,NLK)蛋白质表达。结果TNF-α组细胞的染色强度明显减弱且钙化结节的数量明显减少,TNF-α+SB203580组的染色强度、钙化结节数量较TNF-α组得到明显改善,TNF-α+SB203580+XAV939组细胞的染色强度、钙化结节数量与TNF-α+SB203580组差别不明显。与对照组比较,TNF-α组ALP活性和Runx2、OCN、OSX、OPN mRNA水平降低(P<0.05),P38 MAPK蛋白质表达(P<0.05),β-catenin、CaMKⅡ、NLK蛋白质表达降低(P<0.05)。与TNF-α组比较,TNF-α+SB203580组ALP活性和Runx2、OCN、OSX、OPN mRNA水平升高(P<0.05),P38 MAPK蛋白表达质降低(P<0.05),β-catenin、CaMKⅡ、NLK蛋白质表达升高(P<0.05)。与TNF-α+SB203580组,TNF-α+SB203580+XAV939组β-catenin蛋白质表达降低(P<0.05),但ALP活性、Runx2、OCN、OSX、OPN mRNA水平和P38 MAPK、CaMKⅡ、NLK蛋白质表达比较无统计差异(P>0.05)。结论炎症微环境下条件下P38 MAPK抑制剂可提高PDLSC成骨分化能力,可能与激活Wnt/Ca^(2+)信号通路有关。

Spatial Inhomogeneity of Atmospheric CO_(2) Concentration and Its Uncertainty in CMIP6 Earth System Models

This paper provides a systematic evaluation of the ability of 12 Earth System Models(ESMs)participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)to simulate the spatial inhomogeneity of the atmospheric carbon dioxide(CO_(2))concentration.The multi-model ensemble mean(MME)can reasonably simulate the increasing trend of CO_(2) concentration from 1850 to 2014,compared with the observation data from the Scripps CO_(2) Program and CMIP6 prescribed data,and improves upon the CMIP5 MME CO_(2) concentration(which is overestimated after 1950).The growth rate of CO_(2) concentration in the northern hemisphere(NH)is higher than that in the southern hemisphere(SH),with the highest growth rate in the mid-latitudes of the NH.The MME can also reasonably simulate the seasonal amplitude of CO_(2) concentration,which is larger in the NH than in the SH and grows in amplitude after the 1950s(especially in the NH).Although the results of the MME are reasonable,there is a large spread among ESMs,and the difference between the ESMs increases with time.The MME results show that regions with relatively large CO_(2) concentrations(such as northern Russia,eastern China,Southeast Asia,the eastern United States,northern South America,and southern Africa)have greater seasonal variability and also exhibit a larger inter-model spread.Compared with CMIP5,the CMIP6 MME simulates an average spatial distribution of CO_(2) concentration that is much closer to the site observations,but the CMIP6-inter-model spread is larger.The inter-model differences of the annual means and seasonal cycles of atmospheric CO_(2) concentration are both attributed to the differences in natural sources and sinks of CO_(2) between the simulations.