BACKGROUND： Ketamine is a noncompetitive N-methyl-D-aspartate （NMDA） receptor antagonists and plays an important role in the treatment of pain. OBJECTIVE： To analyze the preemptive analgesic effects of different d...BACKGROUND： Ketamine is a noncompetitive N-methyl-D-aspartate （NMDA） receptor antagonists and plays an important role in the treatment of pain. OBJECTIVE： To analyze the preemptive analgesic effects of different doses of ketamine on growth-associated protein-43 （GAP43） expression in dorsal root ganglion in a rat model of chronic sciatic nerve constricted injury, and to study the differences between high-dose and low-dose ketamine DESIGN： Randomized controlled animal study. SETTING： Medical College of Shantou University. MATERIALS： Thirty-five adult male Sprague Dawley rats were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. Ketamine hydrochloride injection was provided by Hengrui Pharmaceutical Co., Ltd., Jiangsu. METHODS： This study was performed at the Immunological Laboratory, Medical College of Shantou University from September to December 2006. Model of chronic sciatic nerve constricted injury： after anesthesia, the right sciatic nerve was exposed and ligated l-cm distal to the ischiadic tuberosity with a No. 3-0 cat gut suture. Grouping and intervention： 35 rats were randomly divided into 4 groups： normal control group （n = 5）, chronic constriction injury （CCI） group （n = 10）, low-dose ketamine group （n = 10）, and high-dose ketamine group （n = 10）. Rats in the normal control group did not undergo any surgery or drug intervention. Rats in the CCI group received intraperitoneal injection of saline （1 mL）, and their sciatic nerves were ligated after 10 minutes. Rats in the low-dose ketamine group underwent intraperitoneal injection of ketamine （25 mg/kg） 10 minutes prior to ligation of sciatic nerve; while, rats in the high-dose ketamine group were given intraperitoneal injection of ketamine （50 mg/kg） 10 minutes prior to ligation of sciatic nerve. On the third and the seventh days after surgery, dorsal root ganglion were resected from the sciatic nerve and cut into sections. MAIN OUTCOME MEASURES： GAP-43 expression in dorsal root ganglion was detected by immunohistochemistry and image analysis system, as well as semi-quantitative analysis. RESULTS： Thirty-five Sprague Dawley rats were included in the final analysis. Qualitative analysis： GAP-43 expression in the CCI group was higher than in the normal control group. Quantitative analysis： after three post-operative days, GAP-43 expression in the CCI group was significantly higher than in the normal control group （t = 22.919, 7.319, P 〈 0.05）. GAP-43 expression in the low-dose and high-dose ketamine group was significantly lower than in the CCI group （t = 11.166, 26.474, P 〈 0.05）. After seven postoperative days, GAP-43 expression in the low-dose and high-dose ketamine groups was significantly lower than in the CCI group （t = 2.382, 5.016, P 〈 0.05）. CONCLUSION： Preoperative administration of ketamine inhibited the increased GAP-43 expression in dorsal root ganglion during neuropathic pain.展开更多
Objective To investigate whether chronic constriction injury(CCI)of the sciatic nerve of rats could produce alterations in the phosphorylation of cyclic AMP response element binding(CREB)protein in dorsal root ganglia...Objective To investigate whether chronic constriction injury(CCI)of the sciatic nerve of rats could produce alterations in the phosphorylation of cyclic AMP response element binding(CREB)protein in dorsal root ganglia(DRG)and superficial dorsal horn neurons of the spinal cord.Methods Chronic constriction injury(CCI)of the sciatic nerve was employed as a model of neuropathic pain.Thirty-two Sprague-Dawley rats were randomly divided into Na⒍ve,Sham,CCI2w(received CCI for2weeks)and CCI4w(received CCI for4weeks)groups.Hind pawwithdrawal threshold to mechanical stimuli and withdrawal latency to thermal stimuli were used to determine the mechanical and thermal hyperalgesia.Then all the rats were deeply anesthetized and perfused intracardially with paraformaldehyde.The fixed L 4-5 spinal cord and the L 5 DRG ipsilateral to CCI were harvested for fixation.The pCREB-immunoreactive(pCREB-IR)cells in both DRG and superficial dorsal horn neurons were quantified for analysis using immunohistochemistry methods.Results On the14th day after sciatic nerve injury,all the rats exhibited significant mechanical and thermal hyperalgesia.The mechanical withdrawal thresholds to von Frey filament from CCI2w group decreased significantly compared to both baseline values and those of Sham group(P<0.01);Thermal withdwal latencies from CCI2w group decreased significantly compared to both baseline values and those of Sham group(P<0.01).Some rats from Sham group also showed mechanical hyperalgesia compared to both baseline values and those of Na⒍ve group(P<0.01).28days after CCI,both mechanical and thermal hypersensitivity were significantly alleviated,with no statistical significance compared to those of Sham group.On the14th day after CCI,the number of pCREB-IR cells significantly increased in ipsilateral L 5 DRGs and superficial dorsal horns(P<0.01)compared to Sham group.The number of phosphorylated CREB-IR cells in the ipsilateral DRGs from Sham group also increased compared to that of Naive rats(P<0.05).There were no significant statistical differences of numbers of CREB-IR neuron between Sham group and CCI4wgroup.Conclusion CCI increases CREB phosphorylation both in DRG and superficial dorsal horn neurons of the lumbar spinal cord,and may be one of the key molecular mechanisms of central and peripheral sensitization following peripheral nerve injury.展开更多
Ciliary neurotrophic factor has neuroprotective effects mediated through signal transducer and Janus kinase（JAK） 2/activator of transcription 3（STAT3） and phosphatidylinositol 3-kinase（PI3 K）/Akt signaling pathw...Ciliary neurotrophic factor has neuroprotective effects mediated through signal transducer and Janus kinase（JAK） 2/activator of transcription 3（STAT3） and phosphatidylinositol 3-kinase（PI3 K）/Akt signaling pathways.Whether ciliary neurotrophic factor is neuroprotective for glutamate-induced excitotoxicity of dorsal root ganglion neurons is poorly understood.In the present study,the in vitro neuroprotective effects of ciliary neurotrophic factor against glutamate-induced excitotoxicity were determined in a primary culture of dorsal root ganglion neurons from Wistar rat embryos at embryonic day 15.Whether the JAK2/STAT3 and PI3 K/Akt signaling pathways were related to the protective effects of ciliary neurotrophic factor was also determined.Glutamate exposure inhibited neurite outgrowth,cell viability,and growth-associated protein 43 expression and promoted apoptotic neuronal cell death,all of which were reversed by the administration of exogenous ciliary neurotrophic factor.Additionally,preincubation with either JAK2 inhibitor AG490 or PI3 K inhibitor LY294002 blocked the neuroprotective effect of ciliary neurotrophic factor.These data indicate that the two pathways JAK2/STAT3 and PI3 K/Akt play major roles in mediating the in vitro neuroprotective effects of ciliary neurotrophic factor on dorsal root ganglion neurons with glutamate-induced neurotoxicity.展开更多
‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristic...‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.展开更多
光合作用同化物分配供给是果实和种子发育的主要限制因子,增加蔗糖分配转运到果实和种子是增产优质的潜在策略。SWEET(sugar will eventually be exported transporter)是近年来被鉴定较多的一类糖转运蛋白,该蛋白质通过从源叶运输营养...光合作用同化物分配供给是果实和种子发育的主要限制因子,增加蔗糖分配转运到果实和种子是增产优质的潜在策略。SWEET(sugar will eventually be exported transporter)是近年来被鉴定较多的一类糖转运蛋白,该蛋白质通过从源叶运输营养物质调控库组织发育,参与植物生长发育以及生物和非生物胁迫反应。SWEET蛋白定位于膜结构,属于MtN3家族,通常包含7个跨膜结构域,其中包含2个MtN3/saliva结构域。随着染色体加倍、片段复制和串联复制等,SWEET基因在物种中得到扩张。SWEET4和SWEET39基因是作物驯化改良过程中选择的关键基因;SWEET9蛋白是蜜腺特异性糖转运蛋白,参与植物蜜腺的进化;SWEET16和SWEET17蛋白参与植物根系生长发育;SWEET11和SWEET15蛋白参与植物种子胚乳填充。本文系统综述了SWEET蛋白的结构、数量、分类、亚细胞定位、成员扩张与进化,分析了SWEET蛋白在叶、茎、根系发育,花药发育,花蜜分泌,种子填充和果实发育等植物生长发育中的功能作用,强调了SWEET蛋白在作物改良中的应用,说明增强源库强度对作物产量提高的可持续性具有重要意义。展开更多
In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radia...In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.展开更多
The mechanism underlying the modulatory effect of substance P（SP） on GABA-activated response in rat dorsal root ganglion（DRG） neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clam...The mechanism underlying the modulatory effect of substance P（SP） on GABA-activated response in rat dorsal root ganglion（DRG） neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA（1–1000 μmol/L） induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons（89.8 %） examined with whole-cell patch-clamp recordings. Bath application of GABA（1–1000 μmol/L） evoked a depolarizing response in 236 out of 257（91.8%） DRG neurons examined with intracellular recordings. Application of SP（0.001–1 μmol/L） suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1（NK1） receptors antagonist spantide but not by L659187 and SR142801（1 μmol/L, n=7）, selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C（PLC） inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca2＋-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the ＂pre-synaptic inhibition＂ evoked by GABA, which may explain its role in pain and neurogenic inflammation.展开更多
In a previous study, heat shock protein 27 was persistently upregulated in ventral motor neurons following nerve root avulsion or crush. Here, we examined whether the upregulation of heat shock protein 27 would increa...In a previous study, heat shock protein 27 was persistently upregulated in ventral motor neurons following nerve root avulsion or crush. Here, we examined whether the upregulation of heat shock protein 27 would increase the survival rate of motor neurons. Rats were divided into two groups： an avulsion-only group （avtflsion of the L4 lumbar nerve root only） and a crush-avulsion group （the L4 lumbar nerve root was crushed 1 week prior to the avulsion）. Immunofluores- cent staining revealed that the survival rate of motor neurons was significantly greater in the crush-avulsion group than in the avulsion-only group, and this difference remained for at least 5 weeks after avulsion. The higher neuronal survival rate may be explained by the upregulation of heat shock protein 27 expression in motor neurons in the crush-avulsion group. Further- more, preconditioning crush greatly attenuated the expression of nitric oxide synthase in the motor neurons. Our findings indicate that the neuroprotective action of preconditioning crush is mediated through the upregulation of heat shock protein 27 expression and the attenuation of neuronal nitric oxide synthase upregulation following avulsion.展开更多
This study investigated the possible involvement of microRNAs in the regulation of genes that participate in peripheral neural regeneration. A microRNA microarray analysis was conducted and 23 microRNAs were identiife...This study investigated the possible involvement of microRNAs in the regulation of genes that participate in peripheral neural regeneration. A microRNA microarray analysis was conducted and 23 microRNAs were identiifed whose expression was signiifcantly changed in rat dorsal root ganglia after sciatic nerve transection. The expression of one of the downregulated microRNAs, microRNA-214, was validated using quantitative reverse transcriptase-PCR. MicroRNA-214 was predicted to target the 3′-untranslated region of Slit-Robo GTPase-activating protein 3. In situ hybridization veriifed that microRNA-214 was located in the cytoplasm of dorsal root ganglia primary neurons and was downregulated following sciatic nerve transection. Moreover, a com-bination of in situ hybridization and immunohistochemistry revealed that microRNA-214 and Slit-Robo GTPase-activating protein 3 were co-localized in dorsal root ganglion primary neu-rons. Western blot analysis suggested that Slit-Robo GTPase-activating protein 3 was upregulated in dorsal root ganglion neurons after sciatic nerve transection. These data demonstrate that mi-croRNA-214 is located and differentially expressed in dorsal root ganglion primary neurons and may participate in regulating the gene expression of Slit-Robo GTPase-activating protein 3 after sciatic nerve transection.展开更多
The role of type-2 astrocytes in the repair of central nervous system injury remains poorly un- derstood. In this study, using a relatively simple culture condition in vitro, type-2 astrocytes, differentiated from oli...The role of type-2 astrocytes in the repair of central nervous system injury remains poorly un- derstood. In this study, using a relatively simple culture condition in vitro, type-2 astrocytes, differentiated from oligodendrocyte precursor cells by induction with bone morphogenetic pro- tein-4, were co-cultured with dorsal root ganglion neurons. We examined the effects of type-2 astrocytes differentiated from oligodendrocyte precursor cells on the survival and growth of dorsal root ganglion neurons. Results demonstrated that the number of dorsal root ganglion neurons was higher following co-culture of oligodendrocyte precursor cells and type-2 astrocytes than when cultured alone, but lower than that of neurons co-cultured with type-1 astrocytes. The length of the longest process and the length of all processes of a single neuron were shortest in neurons cultured alone, followed by neurons co-cultured with type-2 astroc^es, then neurons co-cultured with oligodendrocyte precursor cells, and longest in neurons co-cultured with type-1 astrocytes. These results indicate that co-culture with type-2 astrocytes can increase neuronal survival rate and process length. However, compared with type-1 astrocytes and oligodendrocyte precursor cells, the promotion effects of type-2 astrocytes on the growth of dorsal root ganglion neurons were weaker.展开更多
文摘BACKGROUND： Ketamine is a noncompetitive N-methyl-D-aspartate （NMDA） receptor antagonists and plays an important role in the treatment of pain. OBJECTIVE： To analyze the preemptive analgesic effects of different doses of ketamine on growth-associated protein-43 （GAP43） expression in dorsal root ganglion in a rat model of chronic sciatic nerve constricted injury, and to study the differences between high-dose and low-dose ketamine DESIGN： Randomized controlled animal study. SETTING： Medical College of Shantou University. MATERIALS： Thirty-five adult male Sprague Dawley rats were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. Ketamine hydrochloride injection was provided by Hengrui Pharmaceutical Co., Ltd., Jiangsu. METHODS： This study was performed at the Immunological Laboratory, Medical College of Shantou University from September to December 2006. Model of chronic sciatic nerve constricted injury： after anesthesia, the right sciatic nerve was exposed and ligated l-cm distal to the ischiadic tuberosity with a No. 3-0 cat gut suture. Grouping and intervention： 35 rats were randomly divided into 4 groups： normal control group （n = 5）, chronic constriction injury （CCI） group （n = 10）, low-dose ketamine group （n = 10）, and high-dose ketamine group （n = 10）. Rats in the normal control group did not undergo any surgery or drug intervention. Rats in the CCI group received intraperitoneal injection of saline （1 mL）, and their sciatic nerves were ligated after 10 minutes. Rats in the low-dose ketamine group underwent intraperitoneal injection of ketamine （25 mg/kg） 10 minutes prior to ligation of sciatic nerve; while, rats in the high-dose ketamine group were given intraperitoneal injection of ketamine （50 mg/kg） 10 minutes prior to ligation of sciatic nerve. On the third and the seventh days after surgery, dorsal root ganglion were resected from the sciatic nerve and cut into sections. MAIN OUTCOME MEASURES： GAP-43 expression in dorsal root ganglion was detected by immunohistochemistry and image analysis system, as well as semi-quantitative analysis. RESULTS： Thirty-five Sprague Dawley rats were included in the final analysis. Qualitative analysis： GAP-43 expression in the CCI group was higher than in the normal control group. Quantitative analysis： after three post-operative days, GAP-43 expression in the CCI group was significantly higher than in the normal control group （t = 22.919, 7.319, P 〈 0.05）. GAP-43 expression in the low-dose and high-dose ketamine group was significantly lower than in the CCI group （t = 11.166, 26.474, P 〈 0.05）. After seven postoperative days, GAP-43 expression in the low-dose and high-dose ketamine groups was significantly lower than in the CCI group （t = 2.382, 5.016, P 〈 0.05）. CONCLUSION： Preoperative administration of ketamine inhibited the increased GAP-43 expression in dorsal root ganglion during neuropathic pain.
文摘Objective To investigate whether chronic constriction injury(CCI)of the sciatic nerve of rats could produce alterations in the phosphorylation of cyclic AMP response element binding(CREB)protein in dorsal root ganglia(DRG)and superficial dorsal horn neurons of the spinal cord.Methods Chronic constriction injury(CCI)of the sciatic nerve was employed as a model of neuropathic pain.Thirty-two Sprague-Dawley rats were randomly divided into Na⒍ve,Sham,CCI2w(received CCI for2weeks)and CCI4w(received CCI for4weeks)groups.Hind pawwithdrawal threshold to mechanical stimuli and withdrawal latency to thermal stimuli were used to determine the mechanical and thermal hyperalgesia.Then all the rats were deeply anesthetized and perfused intracardially with paraformaldehyde.The fixed L 4-5 spinal cord and the L 5 DRG ipsilateral to CCI were harvested for fixation.The pCREB-immunoreactive(pCREB-IR)cells in both DRG and superficial dorsal horn neurons were quantified for analysis using immunohistochemistry methods.Results On the14th day after sciatic nerve injury,all the rats exhibited significant mechanical and thermal hyperalgesia.The mechanical withdrawal thresholds to von Frey filament from CCI2w group decreased significantly compared to both baseline values and those of Sham group(P<0.01);Thermal withdwal latencies from CCI2w group decreased significantly compared to both baseline values and those of Sham group(P<0.01).Some rats from Sham group also showed mechanical hyperalgesia compared to both baseline values and those of Na⒍ve group(P<0.01).28days after CCI,both mechanical and thermal hypersensitivity were significantly alleviated,with no statistical significance compared to those of Sham group.On the14th day after CCI,the number of pCREB-IR cells significantly increased in ipsilateral L 5 DRGs and superficial dorsal horns(P<0.01)compared to Sham group.The number of phosphorylated CREB-IR cells in the ipsilateral DRGs from Sham group also increased compared to that of Naive rats(P<0.05).There were no significant statistical differences of numbers of CREB-IR neuron between Sham group and CCI4wgroup.Conclusion CCI increases CREB phosphorylation both in DRG and superficial dorsal horn neurons of the lumbar spinal cord,and may be one of the key molecular mechanisms of central and peripheral sensitization following peripheral nerve injury.
基金supported by the Natural Science Foundation of Shandong Province of China,No.ZR2014HQ065a grant from the Medical Science and Technology Development Project of Shandong Province of China,No.2015WS0445
文摘Ciliary neurotrophic factor has neuroprotective effects mediated through signal transducer and Janus kinase（JAK） 2/activator of transcription 3（STAT3） and phosphatidylinositol 3-kinase（PI3 K）/Akt signaling pathways.Whether ciliary neurotrophic factor is neuroprotective for glutamate-induced excitotoxicity of dorsal root ganglion neurons is poorly understood.In the present study,the in vitro neuroprotective effects of ciliary neurotrophic factor against glutamate-induced excitotoxicity were determined in a primary culture of dorsal root ganglion neurons from Wistar rat embryos at embryonic day 15.Whether the JAK2/STAT3 and PI3 K/Akt signaling pathways were related to the protective effects of ciliary neurotrophic factor was also determined.Glutamate exposure inhibited neurite outgrowth,cell viability,and growth-associated protein 43 expression and promoted apoptotic neuronal cell death,all of which were reversed by the administration of exogenous ciliary neurotrophic factor.Additionally,preincubation with either JAK2 inhibitor AG490 or PI3 K inhibitor LY294002 blocked the neuroprotective effect of ciliary neurotrophic factor.These data indicate that the two pathways JAK2/STAT3 and PI3 K/Akt play major roles in mediating the in vitro neuroprotective effects of ciliary neurotrophic factor on dorsal root ganglion neurons with glutamate-induced neurotoxicity.
基金supported by the national 948 subject ‘Introduction of fresh-eating jujube cultivar and new cultivating technology from Israel(2012-4-61)’
文摘‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.
文摘光合作用同化物分配供给是果实和种子发育的主要限制因子,增加蔗糖分配转运到果实和种子是增产优质的潜在策略。SWEET(sugar will eventually be exported transporter)是近年来被鉴定较多的一类糖转运蛋白,该蛋白质通过从源叶运输营养物质调控库组织发育,参与植物生长发育以及生物和非生物胁迫反应。SWEET蛋白定位于膜结构,属于MtN3家族,通常包含7个跨膜结构域,其中包含2个MtN3/saliva结构域。随着染色体加倍、片段复制和串联复制等,SWEET基因在物种中得到扩张。SWEET4和SWEET39基因是作物驯化改良过程中选择的关键基因;SWEET9蛋白是蜜腺特异性糖转运蛋白,参与植物蜜腺的进化;SWEET16和SWEET17蛋白参与植物根系生长发育;SWEET11和SWEET15蛋白参与植物种子胚乳填充。本文系统综述了SWEET蛋白的结构、数量、分类、亚细胞定位、成员扩张与进化,分析了SWEET蛋白在叶、茎、根系发育,花药发育,花蜜分泌,种子填充和果实发育等植物生长发育中的功能作用,强调了SWEET蛋白在作物改良中的应用,说明增强源库强度对作物产量提高的可持续性具有重要意义。
文摘In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.
基金supported by grants from the National Natural Science Foundation of China(No.30160026)the Youth Science and Technology Innovation Special Foundation of Xinjiang Production and Construction Corps,China(No.2010JC33)
文摘The mechanism underlying the modulatory effect of substance P（SP） on GABA-activated response in rat dorsal root ganglion（DRG） neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA（1–1000 μmol/L） induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons（89.8 %） examined with whole-cell patch-clamp recordings. Bath application of GABA（1–1000 μmol/L） evoked a depolarizing response in 236 out of 257（91.8%） DRG neurons examined with intracellular recordings. Application of SP（0.001–1 μmol/L） suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1（NK1） receptors antagonist spantide but not by L659187 and SR142801（1 μmol/L, n=7）, selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C（PLC） inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca2＋-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the ＂pre-synaptic inhibition＂ evoked by GABA, which may explain its role in pain and neurogenic inflammation.
基金supported by a grant from Education Ministry of Jiangsu Province,No.08KJB310002Excellent Discipline of Jiangsu Province,No.JX10131801096
文摘In a previous study, heat shock protein 27 was persistently upregulated in ventral motor neurons following nerve root avulsion or crush. Here, we examined whether the upregulation of heat shock protein 27 would increase the survival rate of motor neurons. Rats were divided into two groups： an avulsion-only group （avtflsion of the L4 lumbar nerve root only） and a crush-avulsion group （the L4 lumbar nerve root was crushed 1 week prior to the avulsion）. Immunofluores- cent staining revealed that the survival rate of motor neurons was significantly greater in the crush-avulsion group than in the avulsion-only group, and this difference remained for at least 5 weeks after avulsion. The higher neuronal survival rate may be explained by the upregulation of heat shock protein 27 expression in motor neurons in the crush-avulsion group. Further- more, preconditioning crush greatly attenuated the expression of nitric oxide synthase in the motor neurons. Our findings indicate that the neuroprotective action of preconditioning crush is mediated through the upregulation of heat shock protein 27 expression and the attenuation of neuronal nitric oxide synthase upregulation following avulsion.
基金supported by the National Natural Science Foundation of China,No.81160158 and 30860290
文摘This study investigated the possible involvement of microRNAs in the regulation of genes that participate in peripheral neural regeneration. A microRNA microarray analysis was conducted and 23 microRNAs were identiifed whose expression was signiifcantly changed in rat dorsal root ganglia after sciatic nerve transection. The expression of one of the downregulated microRNAs, microRNA-214, was validated using quantitative reverse transcriptase-PCR. MicroRNA-214 was predicted to target the 3′-untranslated region of Slit-Robo GTPase-activating protein 3. In situ hybridization veriifed that microRNA-214 was located in the cytoplasm of dorsal root ganglia primary neurons and was downregulated following sciatic nerve transection. Moreover, a com-bination of in situ hybridization and immunohistochemistry revealed that microRNA-214 and Slit-Robo GTPase-activating protein 3 were co-localized in dorsal root ganglion primary neu-rons. Western blot analysis suggested that Slit-Robo GTPase-activating protein 3 was upregulated in dorsal root ganglion neurons after sciatic nerve transection. These data demonstrate that mi-croRNA-214 is located and differentially expressed in dorsal root ganglion primary neurons and may participate in regulating the gene expression of Slit-Robo GTPase-activating protein 3 after sciatic nerve transection.
基金supported by the NIH Foundation of the USA,No.R01 NS061975the Natural Science Foundation of Hunan Province in China,No.11JJ6077
文摘The role of type-2 astrocytes in the repair of central nervous system injury remains poorly un- derstood. In this study, using a relatively simple culture condition in vitro, type-2 astrocytes, differentiated from oligodendrocyte precursor cells by induction with bone morphogenetic pro- tein-4, were co-cultured with dorsal root ganglion neurons. We examined the effects of type-2 astrocytes differentiated from oligodendrocyte precursor cells on the survival and growth of dorsal root ganglion neurons. Results demonstrated that the number of dorsal root ganglion neurons was higher following co-culture of oligodendrocyte precursor cells and type-2 astrocytes than when cultured alone, but lower than that of neurons co-cultured with type-1 astrocytes. The length of the longest process and the length of all processes of a single neuron were shortest in neurons cultured alone, followed by neurons co-cultured with type-2 astroc^es, then neurons co-cultured with oligodendrocyte precursor cells, and longest in neurons co-cultured with type-1 astrocytes. These results indicate that co-culture with type-2 astrocytes can increase neuronal survival rate and process length. However, compared with type-1 astrocytes and oligodendrocyte precursor cells, the promotion effects of type-2 astrocytes on the growth of dorsal root ganglion neurons were weaker.
