Considerable research is now focusing on abrupt Holocene changes at millennial- and centennial-scales all over the world. This study shows that the changes in theHolocene summer monsoon can be divided into two main pe...Considerable research is now focusing on abrupt Holocene changes at millennial- and centennial-scales all over the world. This study shows that the changes in theHolocene summer monsoon can be divided into two main periods, based on climatic proxy records of lake sediments from the Sanjiaocheng section located at the NW boundary of the summer monsoon, Gansu Province. The early and middle Holocene was humid with stronger summer monsoon, while the late Holocene is dry with weak summer monsoon. Detailed results also show a series of millennial- and centennial-scale changes in the intensity of the summer monsoon, with a periodicity of 1600 years during the whole Holocene, and with a periodicity of 800 years during the early Holocene. Ten dry events during the Holocene are associated with the weakening of the summer monsoon. These rapid climatic changes may be representative of a global climatic change pattern during the Holocene.展开更多
Propelled partly by the Materials Genome Initiative,and partly by the algorithmic developments and the resounding successes of data-driven efforts in other domains,informatics strategies are beginning to take shape wi...Propelled partly by the Materials Genome Initiative,and partly by the algorithmic developments and the resounding successes of data-driven efforts in other domains,informatics strategies are beginning to take shape within materials science.These approaches lead to surrogate machine learning models that enable rapid predictions based purely on past data rather than by direct experimentation or by computations/simulations in which fundamental equations are explicitly solved.Data-centric informatics methods are becoming useful to determine material properties that are hard to measure or compute using traditional methods—due to the cost,time or effort involved—but for which reliable data either already exists or can be generated for at least a subset of the critical cases.Predictions are typically interpolative,involving fingerprinting a material numerically first,and then following a mapping(established via a learning algorithm)between the fingerprint and the property of interest.Fingerprints,also referred to as“descriptors”,may be of many types and scales,as dictated by the application domain and needs.Predictions may also be extrapolative—extending into new materials spaces—provided prediction uncertainties are properly taken into account.This article attempts to provide an overview of some of the recent successful data-driven“materials informatics”strategies undertaken in the last decade,with particular emphasis on the fingerprint or descriptor choices.The review also identifies some challenges the community is facing and those that should be overcome in the near future.展开更多
Infection with hepatitis B virus (HBV) leads to a wide spectrum of clinical presentations ranging from an asymptomatic carrier state to self-limited acute or fulminant hepatitis to chronic hepatitis with progression t...Infection with hepatitis B virus (HBV) leads to a wide spectrum of clinical presentations ranging from an asymptomatic carrier state to self-limited acute or fulminant hepatitis to chronic hepatitis with progression to cirrhosis and hepatocellular carcinoma. Infection with HBV is one of the most common viral diseases affecting man. Both viral factors as well as the host immune response have been implicated in the pathogenesis and clinical outcome of HBV infection. In this review, we will discuss the impact of virus-host interactions for the pathogenesis of HBV infection and liver disease. These interactions include the relevance of naturally occurring viral variants for clinical disease, the role of virus-induced apoptosis for HBV-induced liver cell injury and the impact of antiviral immune responses for outcome of infection.展开更多
The Songliao basin （SB） is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyrodastic and ep...The Songliao basin （SB） is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyrodastic and epiclastic rocks. The volcanic rocks, dating from 110 Ma to 130 Ma, are of geochemically active continental margin type. Fast northward migration of the SB block occurred during the major episodes of the volcanism inferred from their paleomagnetic information. The upper one of the basin fill is dominated by non-marine sag-style sedimentary sequence of silicidastics and minor carbonates. The basin center shifted westwards from the early to late Cretaceous revealed by the GGT seismic velocity structure suggesting dynamic change in the basin evolution. Thus, a superposed basin model is proposed. Evolution of the SB involves three periods including （1） Alptian and pre- Aptian： a retroarc basin and range system of Andes type related to Mongolia-Okhotsk collisional belt （MOCB）; （2） Albian to Companian： a sag-like strike-slip basin under transtension related to oblique subduction of the Pacific plate along the eastern margin of the Eurasian plate; （3） since Maastrichtian： a tectonic inverse basin under compression related to normal subduction of the Pacific plate under the Eurasian plate, characterized by overthrust, westward migration of the depocenter and eastward uplifting of the basin margin.展开更多
治疗药物监测(Therapeutic drug monitoring,TDM),如通过定量测定血清或血浆药物浓度指导用药剂量优化,已经成为对患者进行精神药物治疗的很有价值的工具。在患者用药依从性难以判断、药物耐受性不佳、治疗剂量下无效以及可能存在药代...治疗药物监测(Therapeutic drug monitoring,TDM),如通过定量测定血清或血浆药物浓度指导用药剂量优化,已经成为对患者进行精神药物治疗的很有价值的工具。在患者用药依从性难以判断、药物耐受性不佳、治疗剂量下无效以及可能存在药代动力学药物-药物相互作用等情况下,测定药物浓度是很有用的。在精神科,有可能明显获益于TDM的主要患者群体包括儿童、孕妇、老年患者、智力障碍患者、涉及司法的患者、已知或怀疑携带药代动力学相关基因变异的患者,以及合并躯体疾病影响药代动力学的患者。然而,只有将TDM充分整合到临床治疗过程中去,才能发挥其优化药物治疗的潜在优势。为了促进TDM的合理应用,神经精神药理学与药物精神病学协会(Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie,AGNP)的TDM专家组在2004年发表了精神药物治疗药物监测指南。之后,随着知识不断更新,又有许多可能需要进行TDM的新药上市。因此,本次更新将神经精神药物的种类扩展到了128种,并将其TDM必要性划分为从"强烈推荐"到"可能有用"的四个等级。经过大量细致且全面的文献检索与分门别类的汇总整理,将基于循证医学理念的"治疗参考浓度范围"和"剂量相关参考浓度范围"呈现给大家。本共识指南引入了"实验室警戒浓度"的新概念,即实验室需要马上告知治疗医生的药物浓度上限。本共识指南还给出了诸如药物作为细胞色素P450酶的底物和抑制剂的性质,代谢物与母药浓度比值的常见范围,以及与结果解释相关的内容,还提供了何时将TDM与遗传药理学检测相结合的建议。遵循本指南,有助于改善许多患者精神药物治疗的效果,特别是那些存在药代动力学异常的患者。TDM是一门交叉学科,有时针对看起来不一致的数据,需要多学科坦诚地讨论,只有这样,患者才能从这种合作中展开更多
Macrophages,which are key cellular components of the liver,have emerged as essential players in the maintenance of hepatic homeostasis and in injury and repair processes in acute and chronic liver diseases.Upon liver ...Macrophages,which are key cellular components of the liver,have emerged as essential players in the maintenance of hepatic homeostasis and in injury and repair processes in acute and chronic liver diseases.Upon liver injury,resident Kupffer cells(KCs)sense disturbances in homeostasis,interact with hepatic cell populations and release chemokines to recruit circulating leukocytes,including monocytes,which subsequently differentiate into monocyte-derived macrophages(MoMφs)in the liver.Both KCs and MoMφs contribute to both the progression and resolution of tissue inflammation and injury in various liver diseases.The diversity of hepatic macrophage subsets and their plasticity explain their different functional responses in distinct liver diseases.In this review,we highlight novel findings regarding the origins and functions of hepatic macrophages and discuss the potential of targeting macrophages as a therapeutic strategy for liver disease.展开更多
Growth factors and their corresponding receptors are commonly overexpressed and/or dysregulated in many cancers including hepatocellular cancer （HCC）. Clinical trials indicate that growth factor receptors and their ...Growth factors and their corresponding receptors are commonly overexpressed and/or dysregulated in many cancers including hepatocellular cancer （HCC）. Clinical trials indicate that growth factor receptors and their related signalling pathways play important roles in HCC cancer etiology and progression, thus providing rational targets for innovative cancer therapies. A number of strategies including monoclonal antibodies, tyrosine kinase inhibitors （＂small molecule inhibitors＂） and antisense oligonucleotides have already been evaluated for their potency to inhibit the activity and downstream signalling cascades of these receptors in HCC. First clinical trials have also shown that multi-kinase inhibition is an effective novel treatment strategy in HCC. In this respect sorafenib, an inhibitor of Raf-, VEGF- and PDGF-signalling, is the first multi-kinase inhibitor that has been approved by the FDA for the treatment of advanced HCC. Moreover, the serine-threonine kinase of mammalian target of rapamycin （mTOR） upon which the signalling of several growth factor receptors converge plays a central role in cancer cell proliferation, roTOR inhibition of HCC is currently also being studied in preclinical trials. As HCCs represent hypervascularized neoplasms, inhibition of tumour vessel formation via interfering with the VEGF/VEGFR system is another promising approach in HCC treatment. This review will summarize the current status of the various growth factor receptor-based treatment strategies and in view of the multitude of novel targeted approaches, the rationale for combination therapies for advanced HCC treatment will also be taken into account.展开更多
Ulcerative colitis (UC) is a chronic disease featuring re- current inflammation of the colonic mucosa. The goal of medical treatment is to rapidly induce a steroid-free remission while at the same time preventing comp...Ulcerative colitis (UC) is a chronic disease featuring re- current inflammation of the colonic mucosa. The goal of medical treatment is to rapidly induce a steroid-free remission while at the same time preventing complica- tions of the disease itself and its treatment. The choice of treatment depends on severity, localization and the course of the disease. For proctitis, topical therapy with 5-aminosalicylic acid (5-ASA) compounds is used. More extensive or severe disease should be treated with oral and local 5-ASA compounds and corticosteroids to induce remission. Patients who do not respond to this treatment require hospitalization. Intravenous steroids or, when refractory, calcineurin inhibitors (cyclosporine, tacrolimus), tumor necrosis factor-α antibodies (infliximab) or immunomodulators (azathioprine, 6-mercaptopurine) are then called for. Indications for emergency surgery include refractory toxic megacolon, perforation, and continuous severe colorectal bleeding. Close collaboration between gastroenterologist and surgeon is mandatory in order not to delay surgical therapy when needed. This article is intended to give a general, practice-orientated overview of the key issues in ulcerative colitis treatment. Recommendations are based on published consensus guidelines derived from national and international guidelines on the treatment of ulcerative colitis.展开更多
This paper applies the newest emission scenarios of the sulfur and greenhouse gases, namely IPCC SRES A2 and B2 scenarios, to investigate the change of the North China climate with an atmosphere-ocean coupled general ...This paper applies the newest emission scenarios of the sulfur and greenhouse gases, namely IPCC SRES A2 and B2 scenarios, to investigate the change of the North China climate with an atmosphere-ocean coupled general circulation model. In the last three decades of the 21st century, the global warming enlarges the land-sea thermal contrast, and hence, causes the East Asian summer (winter) monsoon circulation to he strengthened (weakened). The rainfall seasonality strengthens and the summer precipitation increases significantly in North China. It is suggested that the East Asian rainy area would expand northward to North China in the last three decades of the 21st century. In addition, the North China precipitation would increase significantly in September. In July, August, and September, the interannual variability of the precipitation enlarges evidently over North China, implying a risk of flooding in the future.展开更多
Calcium-dependent protein kinases （CDPKs） comprise a family of plant serine/threonine protein kinases in which the calcium sensing domain and the kinase effector domain are combined within one molecule. So far, a bi...Calcium-dependent protein kinases （CDPKs） comprise a family of plant serine/threonine protein kinases in which the calcium sensing domain and the kinase effector domain are combined within one molecule. So far, a biological function in abiotic stress signaling has only been reported for few CDPK isoforms, whereas the underlying biochemical mechanism for these CDPKs is still mainly unknown. Here, we show that CPK21 from Arabidopsis thaliana is biochemically activated in vivo in response to hyperosmotic stress. Loss-of-function seedlings of cpk21 are more tolerant to hyperosmotic stress and mutant plants show increased stress responses with respect to marker gene expression and metabolite accumulation. In transgenic Arabidopsis complementation lines in the cpk21 mutant background, in which either CPK21 wildtype, or a full-length enzyme variant carrying an amino-acid substitution were stably expressed, stress responsitivity was restored by CPK21 but not with the kinase inactive variant. The biochemical characterization of in planta synthesized and purified CPK21 protein revealed that within the calcium-binding domain, N-terminal EF1- and EF2-motifs compared to C-terminal EF3- and EF4-motifs differ in their contribution to calcium-regulated kinase activity, suggesting a crucial role for the N-terminal EF-hand pair. Our data provide evidence for CPK21 contributing in abiotic stress signaling and suggest that the N-terminal EF-hand pair is a calcium-sensing determinant controlling specificity of CPK21 function.展开更多
Roads with very high traffic loads in regions where soils are low in both pH and sorption capacity might be a source of percolation water loaded with heavy metals. Looking at some "worst case" scenarios, thi...Roads with very high traffic loads in regions where soils are low in both pH and sorption capacity might be a source of percolation water loaded with heavy metals. Looking at some "worst case" scenarios, this study focused on the input of traffic related pollutants and on Pb, Cd, Cu, Zn, Ni and Cr concentrations in the soil matrix and soil solution, respectively. The analysis also included pH and electrical conductivity and at some sites DOC. The investigations were carried out on sandy soils with more or less low pH values at four motorway sites in Germany. The average of daily traffic was about 50 000 up to 90 000 vehicles. Soil pore water was collected in two soil depths and at four distances from the road. The pH in general decreased with increasing distance from the roadside. The elevated pH near the roadside was presumably caused by deposition of dust and weathering residues of the road asphalt, as well as by infiltration of salt that was used during winter time. At these road sites, increased heavy metal concentrations in the soil matrix as well as in the soil solution were found. However, the concentrations seldom exceeded reference values of the German Soil Protection Act. The soil solution concentrations tended to increase from the road edge to 10 m distance, whereas the concentration in the soil matrix decreased. Elevated DOC concentrations corresponded with elevated Cu concentrations but did not substantially change this tendency. High soil water percolation rates were found near the roads. Thus, even low metal concentrations of percolation water could yield high metal loads in a narrow area beside the road.展开更多
基金This study was supported by the National Natural Science Foundation of China (Grant No. 49731010)the National Key Basic Research Project on Western Chinese Arid Areas (Grant No. G1999043501).
文摘Considerable research is now focusing on abrupt Holocene changes at millennial- and centennial-scales all over the world. This study shows that the changes in theHolocene summer monsoon can be divided into two main periods, based on climatic proxy records of lake sediments from the Sanjiaocheng section located at the NW boundary of the summer monsoon, Gansu Province. The early and middle Holocene was humid with stronger summer monsoon, while the late Holocene is dry with weak summer monsoon. Detailed results also show a series of millennial- and centennial-scale changes in the intensity of the summer monsoon, with a periodicity of 1600 years during the whole Holocene, and with a periodicity of 800 years during the early Holocene. Ten dry events during the Holocene are associated with the weakening of the summer monsoon. These rapid climatic changes may be representative of a global climatic change pattern during the Holocene.
基金financial support from several grants from the Office of Naval Research that allowed them to explore many applications of machine learning within materials science,including N00014-14-1-0098,N00014-16-1-2580,and N00014-10-1-0944.
文摘Propelled partly by the Materials Genome Initiative,and partly by the algorithmic developments and the resounding successes of data-driven efforts in other domains,informatics strategies are beginning to take shape within materials science.These approaches lead to surrogate machine learning models that enable rapid predictions based purely on past data rather than by direct experimentation or by computations/simulations in which fundamental equations are explicitly solved.Data-centric informatics methods are becoming useful to determine material properties that are hard to measure or compute using traditional methods—due to the cost,time or effort involved—but for which reliable data either already exists or can be generated for at least a subset of the critical cases.Predictions are typically interpolative,involving fingerprinting a material numerically first,and then following a mapping(established via a learning algorithm)between the fingerprint and the property of interest.Fingerprints,also referred to as“descriptors”,may be of many types and scales,as dictated by the application domain and needs.Predictions may also be extrapolative—extending into new materials spaces—provided prediction uncertainties are properly taken into account.This article attempts to provide an overview of some of the recent successful data-driven“materials informatics”strategies undertaken in the last decade,with particular emphasis on the fingerprint or descriptor choices.The review also identifies some challenges the community is facing and those that should be overcome in the near future.
文摘Infection with hepatitis B virus (HBV) leads to a wide spectrum of clinical presentations ranging from an asymptomatic carrier state to self-limited acute or fulminant hepatitis to chronic hepatitis with progression to cirrhosis and hepatocellular carcinoma. Infection with HBV is one of the most common viral diseases affecting man. Both viral factors as well as the host immune response have been implicated in the pathogenesis and clinical outcome of HBV infection. In this review, we will discuss the impact of virus-host interactions for the pathogenesis of HBV infection and liver disease. These interactions include the relevance of naturally occurring viral variants for clinical disease, the role of virus-induced apoptosis for HBV-induced liver cell injury and the impact of antiviral immune responses for outcome of infection.
文摘The Songliao basin （SB） is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyrodastic and epiclastic rocks. The volcanic rocks, dating from 110 Ma to 130 Ma, are of geochemically active continental margin type. Fast northward migration of the SB block occurred during the major episodes of the volcanism inferred from their paleomagnetic information. The upper one of the basin fill is dominated by non-marine sag-style sedimentary sequence of silicidastics and minor carbonates. The basin center shifted westwards from the early to late Cretaceous revealed by the GGT seismic velocity structure suggesting dynamic change in the basin evolution. Thus, a superposed basin model is proposed. Evolution of the SB involves three periods including （1） Alptian and pre- Aptian： a retroarc basin and range system of Andes type related to Mongolia-Okhotsk collisional belt （MOCB）; （2） Albian to Companian： a sag-like strike-slip basin under transtension related to oblique subduction of the Pacific plate along the eastern margin of the Eurasian plate; （3） since Maastrichtian： a tectonic inverse basin under compression related to normal subduction of the Pacific plate under the Eurasian plate, characterized by overthrust, westward migration of the depocenter and eastward uplifting of the basin margin.
文摘治疗药物监测(Therapeutic drug monitoring,TDM),如通过定量测定血清或血浆药物浓度指导用药剂量优化,已经成为对患者进行精神药物治疗的很有价值的工具。在患者用药依从性难以判断、药物耐受性不佳、治疗剂量下无效以及可能存在药代动力学药物-药物相互作用等情况下,测定药物浓度是很有用的。在精神科,有可能明显获益于TDM的主要患者群体包括儿童、孕妇、老年患者、智力障碍患者、涉及司法的患者、已知或怀疑携带药代动力学相关基因变异的患者,以及合并躯体疾病影响药代动力学的患者。然而,只有将TDM充分整合到临床治疗过程中去,才能发挥其优化药物治疗的潜在优势。为了促进TDM的合理应用,神经精神药理学与药物精神病学协会(Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie,AGNP)的TDM专家组在2004年发表了精神药物治疗药物监测指南。之后,随着知识不断更新,又有许多可能需要进行TDM的新药上市。因此,本次更新将神经精神药物的种类扩展到了128种,并将其TDM必要性划分为从"强烈推荐"到"可能有用"的四个等级。经过大量细致且全面的文献检索与分门别类的汇总整理,将基于循证医学理念的"治疗参考浓度范围"和"剂量相关参考浓度范围"呈现给大家。本共识指南引入了"实验室警戒浓度"的新概念,即实验室需要马上告知治疗医生的药物浓度上限。本共识指南还给出了诸如药物作为细胞色素P450酶的底物和抑制剂的性质,代谢物与母药浓度比值的常见范围,以及与结果解释相关的内容,还提供了何时将TDM与遗传药理学检测相结合的建议。遵循本指南,有助于改善许多患者精神药物治疗的效果,特别是那些存在药代动力学异常的患者。TDM是一门交叉学科,有时针对看起来不一致的数据,需要多学科坦诚地讨论,只有这样,患者才能从这种合作中
基金supported by the Federal Ministry of Education and Research(BMBF,ImmuneAvatar)supported by NIH grants DK109574,DK121330,DK122708,and DK122796supported by the German Research Foundation(DFG SFB/TRR296,CRC1382,Ta434/3-1,and Ta434/5-1).
文摘Macrophages,which are key cellular components of the liver,have emerged as essential players in the maintenance of hepatic homeostasis and in injury and repair processes in acute and chronic liver diseases.Upon liver injury,resident Kupffer cells(KCs)sense disturbances in homeostasis,interact with hepatic cell populations and release chemokines to recruit circulating leukocytes,including monocytes,which subsequently differentiate into monocyte-derived macrophages(MoMφs)in the liver.Both KCs and MoMφs contribute to both the progression and resolution of tissue inflammation and injury in various liver diseases.The diversity of hepatic macrophage subsets and their plasticity explain their different functional responses in distinct liver diseases.In this review,we highlight novel findings regarding the origins and functions of hepatic macrophages and discuss the potential of targeting macrophages as a therapeutic strategy for liver disease.
文摘Growth factors and their corresponding receptors are commonly overexpressed and/or dysregulated in many cancers including hepatocellular cancer （HCC）. Clinical trials indicate that growth factor receptors and their related signalling pathways play important roles in HCC cancer etiology and progression, thus providing rational targets for innovative cancer therapies. A number of strategies including monoclonal antibodies, tyrosine kinase inhibitors （＂small molecule inhibitors＂） and antisense oligonucleotides have already been evaluated for their potency to inhibit the activity and downstream signalling cascades of these receptors in HCC. First clinical trials have also shown that multi-kinase inhibition is an effective novel treatment strategy in HCC. In this respect sorafenib, an inhibitor of Raf-, VEGF- and PDGF-signalling, is the first multi-kinase inhibitor that has been approved by the FDA for the treatment of advanced HCC. Moreover, the serine-threonine kinase of mammalian target of rapamycin （mTOR） upon which the signalling of several growth factor receptors converge plays a central role in cancer cell proliferation, roTOR inhibition of HCC is currently also being studied in preclinical trials. As HCCs represent hypervascularized neoplasms, inhibition of tumour vessel formation via interfering with the VEGF/VEGFR system is another promising approach in HCC treatment. This review will summarize the current status of the various growth factor receptor-based treatment strategies and in view of the multitude of novel targeted approaches, the rationale for combination therapies for advanced HCC treatment will also be taken into account.
文摘Ulcerative colitis (UC) is a chronic disease featuring re- current inflammation of the colonic mucosa. The goal of medical treatment is to rapidly induce a steroid-free remission while at the same time preventing complica- tions of the disease itself and its treatment. The choice of treatment depends on severity, localization and the course of the disease. For proctitis, topical therapy with 5-aminosalicylic acid (5-ASA) compounds is used. More extensive or severe disease should be treated with oral and local 5-ASA compounds and corticosteroids to induce remission. Patients who do not respond to this treatment require hospitalization. Intravenous steroids or, when refractory, calcineurin inhibitors (cyclosporine, tacrolimus), tumor necrosis factor-α antibodies (infliximab) or immunomodulators (azathioprine, 6-mercaptopurine) are then called for. Indications for emergency surgery include refractory toxic megacolon, perforation, and continuous severe colorectal bleeding. Close collaboration between gastroenterologist and surgeon is mandatory in order not to delay surgical therapy when needed. This article is intended to give a general, practice-orientated overview of the key issues in ulcerative colitis treatment. Recommendations are based on published consensus guidelines derived from national and international guidelines on the treatment of ulcerative colitis.
基金supported by the Key Project of the Chinese Academy of Sciences(KZCX2-SW-210)the Key Project of the Chinese Academy of Sciences(KZCX2-203)the National Key Programme for Developing Basic Sciences(G1998040904).
文摘This paper applies the newest emission scenarios of the sulfur and greenhouse gases, namely IPCC SRES A2 and B2 scenarios, to investigate the change of the North China climate with an atmosphere-ocean coupled general circulation model. In the last three decades of the 21st century, the global warming enlarges the land-sea thermal contrast, and hence, causes the East Asian summer (winter) monsoon circulation to he strengthened (weakened). The rainfall seasonality strengthens and the summer precipitation increases significantly in North China. It is suggested that the East Asian rainy area would expand northward to North China in the last three decades of the 21st century. In addition, the North China precipitation would increase significantly in September. In July, August, and September, the interannual variability of the precipitation enlarges evidently over North China, implying a risk of flooding in the future.
文摘Calcium-dependent protein kinases （CDPKs） comprise a family of plant serine/threonine protein kinases in which the calcium sensing domain and the kinase effector domain are combined within one molecule. So far, a biological function in abiotic stress signaling has only been reported for few CDPK isoforms, whereas the underlying biochemical mechanism for these CDPKs is still mainly unknown. Here, we show that CPK21 from Arabidopsis thaliana is biochemically activated in vivo in response to hyperosmotic stress. Loss-of-function seedlings of cpk21 are more tolerant to hyperosmotic stress and mutant plants show increased stress responses with respect to marker gene expression and metabolite accumulation. In transgenic Arabidopsis complementation lines in the cpk21 mutant background, in which either CPK21 wildtype, or a full-length enzyme variant carrying an amino-acid substitution were stably expressed, stress responsitivity was restored by CPK21 but not with the kinase inactive variant. The biochemical characterization of in planta synthesized and purified CPK21 protein revealed that within the calcium-binding domain, N-terminal EF1- and EF2-motifs compared to C-terminal EF3- and EF4-motifs differ in their contribution to calcium-regulated kinase activity, suggesting a crucial role for the N-terminal EF-hand pair. Our data provide evidence for CPK21 contributing in abiotic stress signaling and suggest that the N-terminal EF-hand pair is a calcium-sensing determinant controlling specificity of CPK21 function.
基金supported by the German Federal Highway Research Institute (No. 15.305/1998/GRB)
文摘Roads with very high traffic loads in regions where soils are low in both pH and sorption capacity might be a source of percolation water loaded with heavy metals. Looking at some "worst case" scenarios, this study focused on the input of traffic related pollutants and on Pb, Cd, Cu, Zn, Ni and Cr concentrations in the soil matrix and soil solution, respectively. The analysis also included pH and electrical conductivity and at some sites DOC. The investigations were carried out on sandy soils with more or less low pH values at four motorway sites in Germany. The average of daily traffic was about 50 000 up to 90 000 vehicles. Soil pore water was collected in two soil depths and at four distances from the road. The pH in general decreased with increasing distance from the roadside. The elevated pH near the roadside was presumably caused by deposition of dust and weathering residues of the road asphalt, as well as by infiltration of salt that was used during winter time. At these road sites, increased heavy metal concentrations in the soil matrix as well as in the soil solution were found. However, the concentrations seldom exceeded reference values of the German Soil Protection Act. The soil solution concentrations tended to increase from the road edge to 10 m distance, whereas the concentration in the soil matrix decreased. Elevated DOC concentrations corresponded with elevated Cu concentrations but did not substantially change this tendency. High soil water percolation rates were found near the roads. Thus, even low metal concentrations of percolation water could yield high metal loads in a narrow area beside the road.
