火灾与气候、植被存在复杂的关系,搞清东亚季风区的火灾模式及其发生机制,对预测未来气候变化及火灾防治具有重要意义。通过对黔西高原MIS3—MIS2期间的古湖相沉积物进行炭屑分析并结合AMS^(14)C测年数据研究发现:MIS3晚期以来研究区的...火灾与气候、植被存在复杂的关系,搞清东亚季风区的火灾模式及其发生机制,对预测未来气候变化及火灾防治具有重要意义。通过对黔西高原MIS3—MIS2期间的古湖相沉积物进行炭屑分析并结合AMS^(14)C测年数据研究发现:MIS3晚期以来研究区的火灾主要发生于36.3—35 cal ka BP、26.2—17.6 cal ka BP期间,中粒炭屑和大炭屑分别在35、26.2、23.6 cal ka BP记录到3次地方火。研究区炭屑记录对冷干事件响应敏感,炭屑峰值区对应Heinrich事件(H事件)、末次冰盛期(LGM)等干旱事件,低值区对应DO事件,呈现千年旋回的特征。比对东亚地区的炭屑记录发现,在大范围的东亚季风区MIS2期比MIS3末期在火的强度和频率上都要高,与欧洲模式显著不同。火的发生机制可能受气候因素的控制,同时受植被类型的影响。展开更多
Spinal cord injury （SCI） is a devastating type of neurological trauma with limited therapeutic op- portunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary...Spinal cord injury （SCI） is a devastating type of neurological trauma with limited therapeutic op- portunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary injury mechanisms, the inflammatory response is the major contrib- utor and results in expansion of the lesion and further loss of neurologic function. Meanwhile, the inflammation directly and indirectly dominates the outcomes of SCI, including not only pain and motor dysfunction, but also preventingneuronal regeneration. Microglia and macrophages play very important roles in secondary injury. Microglia reside in spinal parenchyma and survey the microenvironment through the signals of injury or infection. Macrophages are derived from monocytes recruited to injured sites from the peripheral circulation. Activated resident microglia and monocyte-derived macrophages induce and magnify immune and inflammatory responses not only by means of their secretory moleculesand phagocytosis, but also through their influence on astrocytes, oligodendrocytes and demyelination. In this review, we focus on the roles of mi- croglia and macrophages in secondary injury and how they contribute to the sequelae of SCI.展开更多
利用AMS14C测年,结合地层沉积物特点,对中亚哈萨克斯坦南部Valikhanov黄土-古土壤沉积剖面进行孢粉浓度分析。沉积地层自下而上分为4个孢粉带(V1~V4),V1带蒿属花粉浓度高于其它种属;V2带孢粉种类丰富多样而且稳定;V3带总孢粉浓度比前面...利用AMS14C测年,结合地层沉积物特点,对中亚哈萨克斯坦南部Valikhanov黄土-古土壤沉积剖面进行孢粉浓度分析。沉积地层自下而上分为4个孢粉带(V1~V4),V1带蒿属花粉浓度高于其它种属;V2带孢粉种类丰富多样而且稳定;V3带总孢粉浓度比前面带段增加,草原成分的草本植物花粉浓度变化剧烈;V4带总孢粉浓度尤其是藜科和麻黄花粉浓度迅速大幅增加。揭示了中亚干旱区28000年以来植被和气候演化历史:28~1814C ka B.P.,植被是以蒿为主的干草原,气候寒冷并且偏湿润;18~1014C ka B.P.,植被为蒿属植物占绝对优势的温带草原,气候偏湿润;10~514C ka B.P.,植被为蒿-藜沙漠草原,气候干旱;514C ka B.P.以后,植被为藜-蒿草原,气候湿润。展开更多
Introduction A 405-cm sediment section GM02 from Gomo Co salt lake in the northern Tibetan Plateau was used to reconstruct climate changes during marine isotope stage(MIS)2,including the Last Glacial Maximum(LGM)and last
Root-knot nematodes(RKNs)cause huge agricultural losses every year.They secrete a repertoire of effectors to facilitate parasitism through the induction of plant-derived giant feeding cells,which serve as their sole s...Root-knot nematodes(RKNs)cause huge agricultural losses every year.They secrete a repertoire of effectors to facilitate parasitism through the induction of plant-derived giant feeding cells,which serve as their sole source of nutrients.However,the mode of action of these effectors and their targeted host pro-teins remain largely unknown.In this study,we investigated the role of the effector Mi2G02 in Meloidogyne incognita parasitism.Host-derived Mi2G02 RNA interference in Arabidopsis thaliana affected giant cell development,whereas ectopic expression of Mi2G02 promoted root growth and increased plant sus-ceptibility to M.incognita.We used various combinations of approaches to study the specific interactions between Mi2G02 and A.thaliana GT-3a,a trihelix transcription factor.GT-3a knockout in A.thaliana affected feeding-site development,resulting in production of fewer egg masses,whereas GT-3a overex-pression in A.thaliana increased susceptibility to M.incognita and also root growth.Moreover,we demon-strated that Mi2G02 plays a role in maintaining GT-3a protein stabilization by inhibiting the 26S proteasome-dependent pathway,leading to suppression of TOZ and RAD23C expression and thus promoting nematode parasitism.This work enhances our understanding of how a pathogen effector manipulates the role and regulation of a transcription factor by interfering with a proteolysis pathway to reprogram gene expression for development of nematode feeding cells.展开更多
Whether there were more extensive glaciations during the Marine Isotope Stage(MIS)3 relative to MIS 2 across the Tian Shan in Central Asia is intensely debated because of the uncertainty in chronological data and full...Whether there were more extensive glaciations during the Marine Isotope Stage(MIS)3 relative to MIS 2 across the Tian Shan in Central Asia is intensely debated because of the uncertainty in chronological data and fully understanding the driving mechanisms.To help resolve the ongoing debate,we assess the climate sensitivity of the glaciers and reconstruct the extent of glaciation during MIS 2 and 3 across the Tian Shan,using a glacier-resolving(250×250 m)ice sheet model asynchronously coupled with a global climate model.Our results demonstrate that the equilibrium-line altitude(ELA)over the Tian Shan decreases by∼180 m for every 1°C cooling under a modern precipitation regime,but precipitation reduction greatly lowers the sensitivity of the glaciers to temperature decrease(e.g.,the effect of 2°C cooling is broadly offset by a 50%decrease in precipitation).Under the modeled colder/drier-than-present climate,the model predicts an ELA depression(∆ELA)of∼75 m(162 m)over the Tian Shan during MIS 3 interstadials(stadials).The extent of MIS 3 glaciation is much smaller than that during MIS 2(i.e.,∆ELA=∼726 m).The more extensive glaciation during MIS 2 is largely attributed to the enhanced summer cooling.Furthermore,through a site-to-site model-data comparison,we find that the closest match between the modeled glacier margin and the locations of the glacial deposits previously argued to be MIS 3 is generally achieved under MIS 2 climatic conditions.These results suggest more extensive glacier advances over the Tian Shan during MIS 2 than MIS 3 on a regional scale,although MIS 3 glaciation may still occur in individual glacier catchments.This pattern suggests general synchronicity with the timing of maximum Northern Hemisphere ice sheets during the last glacial,which should be further tested in a multimodel framework in the future.展开更多
The bacterium Rhodococcus erythropolis MI2 uses 4,4´-dithiodibutyric acid(DTDB)as carbon source to synthesize polythioesters(PTE).The first step for the production of PTE using DTDB is catalyzed by an NADH:flavin...The bacterium Rhodococcus erythropolis MI2 uses 4,4´-dithiodibutyric acid(DTDB)as carbon source to synthesize polythioesters(PTE).The first step for the production of PTE using DTDB is catalyzed by an NADH:flavin oxidoreductase(nox)as it was previously shown in our laboratory,and the second step is catabolized by a putative luciferase-like monooxygenase(Llm).In the current study,experiments were carried out to identify the function of Llm.Hence,the llm gene,which encodes for the Llm protein,was amplified from the genomic DNA of MI2 using polymerase chain reaction and expressed in Escherichia coli BL21 cells.Protein purification was done using His Spin Trap affinity columns.Enzyme assay was carried out using the purified protein and p-coumaric acid as substrate giving a specific activity of 1.6 U/mg protein for the purified Llm.The responsible gene(llm)was deleted in the genome of MI2,and a single deletion mutant was subsequently generated.Finally,growth of the wild-type strain(MI2)and the mutant strain(MI2Δllm)were compared using DTDB or succinate as carbon sources.Whereas the wild type was successfully grown with DTDB or succinate,the llm-negative mutant exhibited low grow with DTDB although it grows very well with succinate.展开更多
文摘火灾与气候、植被存在复杂的关系,搞清东亚季风区的火灾模式及其发生机制,对预测未来气候变化及火灾防治具有重要意义。通过对黔西高原MIS3—MIS2期间的古湖相沉积物进行炭屑分析并结合AMS^(14)C测年数据研究发现:MIS3晚期以来研究区的火灾主要发生于36.3—35 cal ka BP、26.2—17.6 cal ka BP期间,中粒炭屑和大炭屑分别在35、26.2、23.6 cal ka BP记录到3次地方火。研究区炭屑记录对冷干事件响应敏感,炭屑峰值区对应Heinrich事件(H事件)、末次冰盛期(LGM)等干旱事件,低值区对应DO事件,呈现千年旋回的特征。比对东亚地区的炭屑记录发现,在大范围的东亚季风区MIS2期比MIS3末期在火的强度和频率上都要高,与欧洲模式显著不同。火的发生机制可能受气候因素的控制,同时受植被类型的影响。
基金supported by grants from National Institutes of Health(R01GM100474)the New Jersey Commission on Spinal Cord Research(CSCR13IRG006)
文摘Spinal cord injury （SCI） is a devastating type of neurological trauma with limited therapeutic op- portunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary injury mechanisms, the inflammatory response is the major contrib- utor and results in expansion of the lesion and further loss of neurologic function. Meanwhile, the inflammation directly and indirectly dominates the outcomes of SCI, including not only pain and motor dysfunction, but also preventingneuronal regeneration. Microglia and macrophages play very important roles in secondary injury. Microglia reside in spinal parenchyma and survey the microenvironment through the signals of injury or infection. Macrophages are derived from monocytes recruited to injured sites from the peripheral circulation. Activated resident microglia and monocyte-derived macrophages induce and magnify immune and inflammatory responses not only by means of their secretory moleculesand phagocytosis, but also through their influence on astrocytes, oligodendrocytes and demyelination. In this review, we focus on the roles of mi- croglia and macrophages in secondary injury and how they contribute to the sequelae of SCI.
文摘利用AMS14C测年,结合地层沉积物特点,对中亚哈萨克斯坦南部Valikhanov黄土-古土壤沉积剖面进行孢粉浓度分析。沉积地层自下而上分为4个孢粉带(V1~V4),V1带蒿属花粉浓度高于其它种属;V2带孢粉种类丰富多样而且稳定;V3带总孢粉浓度比前面带段增加,草原成分的草本植物花粉浓度变化剧烈;V4带总孢粉浓度尤其是藜科和麻黄花粉浓度迅速大幅增加。揭示了中亚干旱区28000年以来植被和气候演化历史:28~1814C ka B.P.,植被是以蒿为主的干草原,气候寒冷并且偏湿润;18~1014C ka B.P.,植被为蒿属植物占绝对优势的温带草原,气候偏湿润;10~514C ka B.P.,植被为蒿-藜沙漠草原,气候干旱;514C ka B.P.以后,植被为藜-蒿草原,气候湿润。
基金supported by the National Science Foundation of China (No: 40872031)Geological Survey of China (No: 12120113005600)
文摘Introduction A 405-cm sediment section GM02 from Gomo Co salt lake in the northern Tibetan Plateau was used to reconstruct climate changes during marine isotope stage(MIS)2,including the Last Glacial Maximum(LGM)and last
基金supported by the Youth Innovation Program of the Chinese Academy of Agricultural Sciences (grant no.Y2022QC06)the National Natural Science Foundation of China (grant nos.32001878,32172366)+2 种基金the Natural Science Foundation of Beijing (grant no.6222054)the China Agricultural Research System (CARS-23)the French Government (National Research Agency,ANR)through"Investments for the Future"LabEx SIGNALIFE (#ANR-11-LABX-0028-01),IDEX UCAJedi (#ANR-15-IDEX-0).
文摘Root-knot nematodes(RKNs)cause huge agricultural losses every year.They secrete a repertoire of effectors to facilitate parasitism through the induction of plant-derived giant feeding cells,which serve as their sole source of nutrients.However,the mode of action of these effectors and their targeted host pro-teins remain largely unknown.In this study,we investigated the role of the effector Mi2G02 in Meloidogyne incognita parasitism.Host-derived Mi2G02 RNA interference in Arabidopsis thaliana affected giant cell development,whereas ectopic expression of Mi2G02 promoted root growth and increased plant sus-ceptibility to M.incognita.We used various combinations of approaches to study the specific interactions between Mi2G02 and A.thaliana GT-3a,a trihelix transcription factor.GT-3a knockout in A.thaliana affected feeding-site development,resulting in production of fewer egg masses,whereas GT-3a overex-pression in A.thaliana increased susceptibility to M.incognita and also root growth.Moreover,we demon-strated that Mi2G02 plays a role in maintaining GT-3a protein stabilization by inhibiting the 26S proteasome-dependent pathway,leading to suppression of TOZ and RAD23C expression and thus promoting nematode parasitism.This work enhances our understanding of how a pathogen effector manipulates the role and regulation of a transcription factor by interfering with a proteolysis pathway to reprogram gene expression for development of nematode feeding cells.
基金funded by the National Natural Science Foundation of China(42022036,41888101)the Youth Innovation Promotion Association by CAS(2019080).
文摘Whether there were more extensive glaciations during the Marine Isotope Stage(MIS)3 relative to MIS 2 across the Tian Shan in Central Asia is intensely debated because of the uncertainty in chronological data and fully understanding the driving mechanisms.To help resolve the ongoing debate,we assess the climate sensitivity of the glaciers and reconstruct the extent of glaciation during MIS 2 and 3 across the Tian Shan,using a glacier-resolving(250×250 m)ice sheet model asynchronously coupled with a global climate model.Our results demonstrate that the equilibrium-line altitude(ELA)over the Tian Shan decreases by∼180 m for every 1°C cooling under a modern precipitation regime,but precipitation reduction greatly lowers the sensitivity of the glaciers to temperature decrease(e.g.,the effect of 2°C cooling is broadly offset by a 50%decrease in precipitation).Under the modeled colder/drier-than-present climate,the model predicts an ELA depression(∆ELA)of∼75 m(162 m)over the Tian Shan during MIS 3 interstadials(stadials).The extent of MIS 3 glaciation is much smaller than that during MIS 2(i.e.,∆ELA=∼726 m).The more extensive glaciation during MIS 2 is largely attributed to the enhanced summer cooling.Furthermore,through a site-to-site model-data comparison,we find that the closest match between the modeled glacier margin and the locations of the glacial deposits previously argued to be MIS 3 is generally achieved under MIS 2 climatic conditions.These results suggest more extensive glacier advances over the Tian Shan during MIS 2 than MIS 3 on a regional scale,although MIS 3 glaciation may still occur in individual glacier catchments.This pattern suggests general synchronicity with the timing of maximum Northern Hemisphere ice sheets during the last glacial,which should be further tested in a multimodel framework in the future.
基金supported by Alexander von Humboldt(AvH)foundation,Germany(Ref No:IND 1162665 HFST-P)。
文摘The bacterium Rhodococcus erythropolis MI2 uses 4,4´-dithiodibutyric acid(DTDB)as carbon source to synthesize polythioesters(PTE).The first step for the production of PTE using DTDB is catalyzed by an NADH:flavin oxidoreductase(nox)as it was previously shown in our laboratory,and the second step is catabolized by a putative luciferase-like monooxygenase(Llm).In the current study,experiments were carried out to identify the function of Llm.Hence,the llm gene,which encodes for the Llm protein,was amplified from the genomic DNA of MI2 using polymerase chain reaction and expressed in Escherichia coli BL21 cells.Protein purification was done using His Spin Trap affinity columns.Enzyme assay was carried out using the purified protein and p-coumaric acid as substrate giving a specific activity of 1.6 U/mg protein for the purified Llm.The responsible gene(llm)was deleted in the genome of MI2,and a single deletion mutant was subsequently generated.Finally,growth of the wild-type strain(MI2)and the mutant strain(MI2Δllm)were compared using DTDB or succinate as carbon sources.Whereas the wild type was successfully grown with DTDB or succinate,the llm-negative mutant exhibited low grow with DTDB although it grows very well with succinate.
