Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting trigge...Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.展开更多
Ischemic postconditioning renders brain tissue tolerant to brain ischemia,thereby alleviating ischemic brain injury.However,the exact mechanism of action is still unclear.In this study,a rat model of global brain isch...Ischemic postconditioning renders brain tissue tolerant to brain ischemia,thereby alleviating ischemic brain injury.However,the exact mechanism of action is still unclear.In this study,a rat model of global brain ischemia was subjected to ischemic postconditioning treatment using the vessel occlusion method.After 2 hours of ischemia,the bilateral common carotid arteries were blocked immediately for 10 seconds and then perfused for 10 seconds.This procedure was repeated six times.Ischemic postconditioning was found to mitigate hippocampal CA1 neuronal damage in rats with brain ischemia,and up-regulate acid-sensing ion channel 2a expression at the m RNA and protein level.These findings suggest that ischemic postconditioning up-regulates acid-sensing ion channel 2a expression in the rat hippocampus after global brain ischemia,which promotes neuronal tolerance to ischemic brain injury.展开更多
Increasing plant density has been recognized as an effective strategy for boosting maize yields over the past few decades.However,dense planting significantly reduces the internal light intensity and the red to far-re...Increasing plant density has been recognized as an effective strategy for boosting maize yields over the past few decades.However,dense planting significantly reduces the internal light intensity and the red to far-red(R:FR)light ratio in the canopy,which subsequently triggers shade avoidance responses(SAR)that limit further yield enhancements,particularly under high-density conditions.In this study,we identified double B-box containing protein DBB2,a member of the ZmBBX family that is rapidly induced by shade,as a crucial regulator of plant height and SAR.Disruption of DBB2 resulted in shorter internodes,reduced plant height,decreased cell elongation,and diminished sensitivity to shade in maize,effects that can be largely alleviated by external treatment with gibberellins(GA).Furthermore,we discovered that DBB2physically interacted with the transcription factor HY5,inhibiting its transcriptional activation of ZmGA2ox4,a gene encoding a GA2 oxidase that can deactivate GA.This interaction positively influences maize plant height through the GA pathway.Additionally,we found that the induction of ZmDBB2 by shade is mediated by the transcription factor PIF4.Interestingly,DBB2 then interacted with PIF4 to enhance the transcriptional activation of cell elongation-related genes,such as ZmEXPA1,thereby establishing a positive feedback loop promoting cell elongation under canopy shade conditions.Our findings highlight the critical role of BBX proteins in modulating plant height and SAR,presenting them as key genetic targets for developing maize varieties suited to high-density planting conditions.This study also provides new insights into the molecular mechanisms underlying SAR and offers potential strategies for the genetic improvement of maize plant architecture and grain yield.展开更多
Background:In small fiber neuropathy (SFN),thinly myelinated Aδ and unmyelinated C fibers are primarily affected,resulting in sensory and/or autonomic symptoms.Various etiologies have been shown to be associated with...Background:In small fiber neuropathy (SFN),thinly myelinated Aδ and unmyelinated C fibers are primarily affected,resulting in sensory and/or autonomic symptoms.Various etiologies have been shown to be associated with SFN.This study was aimed to analyze a variety of features in peripheral neuropathy (PN) with small fiber involvement.and to compare disease severity among patients with idiopathic PN,PN associated with impaired glucose tolerance (IGT),and metabolic syndrome (MS) PN.Methods:Thirty-eight PN patients with small fiber involvement were enrolled from December 20,2013 to May 31,2016.Patients were divided into idiopathic PN,IGT-related PN,and MS-related PN groups.Detailed medical history and small fiber neuropathy were investigated,and symptom inventory questionnaire was conducted,as well as the visual analog scale.Nerve conduction studies and skin biopsies were also performed.The differences among the groups were analyzed using analysis of variance and Kruskal-Wallis test.Results:Eight patients were diagnosed with pure SFN.lntraepidermal nerve fiber density (I ENFD) weakly correlated with motor conduction velocity (MCV) (r =0.372,P =0.025),and proximal (r =0.383,P =0.021) and distal (r =0.358,P 0.032) compound muscle action potential (CMAP) of the tibial nerve.IENFD also weakly correlated with MCV of the peroneal nerve (r=0.399,P =0.016).IENFD was shown to be significantly different among all groups (x2 =9.901,P-0.007).IENFD was significantly decreased (x2 =23.000,P=0.003) in the MS-related PN group compared to the idiopathic PN group.The MCV of the tibial nerve was significantly different among all groups (x2 =8.172,P 〈 0.017).The proximal (F =4.336,P =0.021) and distal (F =3.262,P =0.049) CMAP of the tibial nerve was also significantly different among all groups.Conclusions:IENFD of patients included in the present study weakly correlated with various electrophysiological parameters.Small and large fibers are more involved in patients with MS-related PN than in patients with idiopathic PN.展开更多
基金the National Natural Science Foundation of China(32270263 to G.L.,32130077 to H.W.,and 32272140 to P.L.)the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2020MC023,ZR2022MC019).
文摘Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.
文摘Ischemic postconditioning renders brain tissue tolerant to brain ischemia,thereby alleviating ischemic brain injury.However,the exact mechanism of action is still unclear.In this study,a rat model of global brain ischemia was subjected to ischemic postconditioning treatment using the vessel occlusion method.After 2 hours of ischemia,the bilateral common carotid arteries were blocked immediately for 10 seconds and then perfused for 10 seconds.This procedure was repeated six times.Ischemic postconditioning was found to mitigate hippocampal CA1 neuronal damage in rats with brain ischemia,and up-regulate acid-sensing ion channel 2a expression at the m RNA and protein level.These findings suggest that ischemic postconditioning up-regulates acid-sensing ion channel 2a expression in the rat hippocampus after global brain ischemia,which promotes neuronal tolerance to ischemic brain injury.
基金supported by the National Natural Science Foundation of China(32270263 to G.L.,32400297 to Q.S.,32372198 to F.K.)the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2022MC019)。
文摘Increasing plant density has been recognized as an effective strategy for boosting maize yields over the past few decades.However,dense planting significantly reduces the internal light intensity and the red to far-red(R:FR)light ratio in the canopy,which subsequently triggers shade avoidance responses(SAR)that limit further yield enhancements,particularly under high-density conditions.In this study,we identified double B-box containing protein DBB2,a member of the ZmBBX family that is rapidly induced by shade,as a crucial regulator of plant height and SAR.Disruption of DBB2 resulted in shorter internodes,reduced plant height,decreased cell elongation,and diminished sensitivity to shade in maize,effects that can be largely alleviated by external treatment with gibberellins(GA).Furthermore,we discovered that DBB2physically interacted with the transcription factor HY5,inhibiting its transcriptional activation of ZmGA2ox4,a gene encoding a GA2 oxidase that can deactivate GA.This interaction positively influences maize plant height through the GA pathway.Additionally,we found that the induction of ZmDBB2 by shade is mediated by the transcription factor PIF4.Interestingly,DBB2 then interacted with PIF4 to enhance the transcriptional activation of cell elongation-related genes,such as ZmEXPA1,thereby establishing a positive feedback loop promoting cell elongation under canopy shade conditions.Our findings highlight the critical role of BBX proteins in modulating plant height and SAR,presenting them as key genetic targets for developing maize varieties suited to high-density planting conditions.This study also provides new insights into the molecular mechanisms underlying SAR and offers potential strategies for the genetic improvement of maize plant architecture and grain yield.
基金This study was supported by the grants from a scientificresearch project of health care of the Ministry of Health ofthe General Logistics Department(No.13BJZ41)CapitalHealth Development Research Project(No.2014-2-5012)Health and Family Planing Project of Hainan Province(No.16A200081).
文摘Background:In small fiber neuropathy (SFN),thinly myelinated Aδ and unmyelinated C fibers are primarily affected,resulting in sensory and/or autonomic symptoms.Various etiologies have been shown to be associated with SFN.This study was aimed to analyze a variety of features in peripheral neuropathy (PN) with small fiber involvement.and to compare disease severity among patients with idiopathic PN,PN associated with impaired glucose tolerance (IGT),and metabolic syndrome (MS) PN.Methods:Thirty-eight PN patients with small fiber involvement were enrolled from December 20,2013 to May 31,2016.Patients were divided into idiopathic PN,IGT-related PN,and MS-related PN groups.Detailed medical history and small fiber neuropathy were investigated,and symptom inventory questionnaire was conducted,as well as the visual analog scale.Nerve conduction studies and skin biopsies were also performed.The differences among the groups were analyzed using analysis of variance and Kruskal-Wallis test.Results:Eight patients were diagnosed with pure SFN.lntraepidermal nerve fiber density (I ENFD) weakly correlated with motor conduction velocity (MCV) (r =0.372,P =0.025),and proximal (r =0.383,P =0.021) and distal (r =0.358,P 0.032) compound muscle action potential (CMAP) of the tibial nerve.IENFD also weakly correlated with MCV of the peroneal nerve (r=0.399,P =0.016).IENFD was shown to be significantly different among all groups (x2 =9.901,P-0.007).IENFD was significantly decreased (x2 =23.000,P=0.003) in the MS-related PN group compared to the idiopathic PN group.The MCV of the tibial nerve was significantly different among all groups (x2 =8.172,P 〈 0.017).The proximal (F =4.336,P =0.021) and distal (F =3.262,P =0.049) CMAP of the tibial nerve was also significantly different among all groups.Conclusions:IENFD of patients included in the present study weakly correlated with various electrophysiological parameters.Small and large fibers are more involved in patients with MS-related PN than in patients with idiopathic PN.
