Malonyl-CoA synthetases may modulate cell responses to abiotic stress by regulating stress-related signaling transduction pathways or activating expression of transcription factors.However,the molecular mechanism of c...Malonyl-CoA synthetases may modulate cell responses to abiotic stress by regulating stress-related signaling transduction pathways or activating expression of transcription factors.However,the molecular mechanism of cold stress tolerance enhanced by malonyl-CoA synthetase is not fully understood.Here,we report that overexpression of the Arabidopsis thaliana malonyl-CoA synthetase gene AAE13.1 resulted in increased cell viability and growth rate and decreased thiobarbituric acid reactive substances under cold stress in rice(Oryza sativa L.),tobacco(Nicotiana tabacum),and slash pine(Pinus elliottii Engelm.).AAE13.1 was associated with cold stress tolerance by increasing the activity of ascorbate peroxidase,catalase,polyphenol oxidase,and peroxidase and the accumulation of acid phosphatase and alkaline phosphatase.Among six rice mitogenactivated protein kinase(MAPK)genes examined,AAE13.1 overexpression increased the expression of OsMAPK genes during cold stress.AAE13.1 activated expression of stressresponse genes OsMAPK1,OsMAPK2,and OsMAPK3,indicating that AAE13.1 enhances cold stress tolerance by regulating expression of MAPK genes in plant cells.These results increase our understanding of cold stress tolerance in species of monocotyledons,dicotyledons,and gymnosperms.展开更多
The full-length genomic DNA of MCAT (Malonyl-CoA:acyl carrier protein transacylase) in Brassica napus was cloned. BnMCAT shares very high identity with AtMCAT in gene sequence and gene structure. A multiple alignment ...The full-length genomic DNA of MCAT (Malonyl-CoA:acyl carrier protein transacylase) in Brassica napus was cloned. BnMCAT shares very high identity with AtMCAT in gene sequence and gene structure. A multiple alignment of the protein sequence showed that BnMCAT shares high identity with other MCATs from E. coli and plants. BnMCAT was expressed in all tissues, such as roots, stems, leaves, flowers, and seeds, and no significant differences in the expression level were found in different embryo stages after pollination. According to an in vitro relative activity analysis, purified recombinant BnMCAT expressed in E. coli had transacylase activity. Although the relative activities of BnMCAT in crude extracts isolated from different staged embryos were similar and showed little variation, a higher relative activity was found in a crude extract isolated from embryos in comparison to leaves. Different relative activities of BnMCAT in crude extracts isolated from cultivars with different oil content were also found, suggesting that the activity of BnMCAT might be a decisive factor for a high oil content. Together, these results showed that BnMCAT is an important enzyme in the FAS system and indicate that BnMCAT might be a new target enzyme for future crop improvement through genetic engineering.展开更多
Aim Malonyl-CoA is regarded as a key signaling molecule in mammalian ceils. It is converted to acetyl-CoA, and to a lesser extent, to malonyl acid and malonylcamitine （C3DC）. Availability of carnitine has been repor...Aim Malonyl-CoA is regarded as a key signaling molecule in mammalian ceils. It is converted to acetyl-CoA, and to a lesser extent, to malonyl acid and malonylcamitine （C3DC）. Availability of carnitine has been reported to be essential for the developing fetus. The objectives of the present study were to analyze associations of malonylcarnitine, acetylcarnitine （C2）, and free carnitine （CO） in subjects with orofacial clefts. Methodology We performed a retrospective analysis of carnitine concentration obtained from a newborn screening program carried out in our institution. Concentrations of whole blood malonylcarnitine, acetylcarnitine, and free carnitine were measured using tandem mass spectrometry. The study group consisted of 51 children with nonsyndromic cleft lip with or without cleft palate. In total, 106 healthy children without congenital anomalies served as controls. Cut-off points were established using likeli-hood ratio values. Results The mean concentration of malonylcarnitine in the cleft group was lower than that of the control group, 0.048 μmol.L^1 vs. 0.058 μmol.L^-1, respectively （P=-0.009）. In patients with orofacial cleft, low malonylcarnitine levels （〈0.047 μmol.L-1） were 1.7 times more predominant than in healthy individuals （P=-0.03）. The mean concentration of acetylcarnitine was also lower in affected newborns in comparison to controls, 33.8 μol.L^-1 vs. 37.8 μmol·L^-1, respectively （P=-0.026）. After analysis of acetylearnitine and free carnitine concentrations, the likelihood ratio test did not indicate valuable cut-offpoints. Conclusion The study provides initial data indicating a potential association between decreased malonylcarnitine and abnormal palatogenesis.展开更多
目的:观察中等强度持续运动(MICT)与高强度间歇运动(HIIT)对高脂膳食大鼠心肌和比目鱼肌超微结构的影响并探讨其机制。方法:5周龄雄性SD大鼠随机分为普通膳食安静组(C)、高脂膳食安静组(F)、高脂膳食MICT组(M)和高脂膳食HIIT组(H),每组8...目的:观察中等强度持续运动(MICT)与高强度间歇运动(HIIT)对高脂膳食大鼠心肌和比目鱼肌超微结构的影响并探讨其机制。方法:5周龄雄性SD大鼠随机分为普通膳食安静组(C)、高脂膳食安静组(F)、高脂膳食MICT组(M)和高脂膳食HIIT组(H),每组8只,高脂膳食饲料脂肪含量为45%。M和H组进行12周坡度为25°的跑台运动,M组进行70%VO_(2)max强度的持续运动,H组进行以5 min 40%~45%VO_(2)max和4 min 95%~99%VO_(2)max强度依次交替的间歇运动。干预结束后检测血清FFA、TG、HDL、LDL含量;透射电镜观察大鼠心肌和比目鱼肌超微结构;Western blot检测心肌和比目鱼肌AMPK、MCD及CPT-1的蛋白表达。结果:与C组比较,F组大鼠体重、Lee`s指数、血清LDL、TG和FFA含量均增加,HDL含量降低(P<0.05);心肌和比目鱼肌AMPK、CPT-1蛋白表达升高,MCD蛋白表达降低(P<0.05),超微结构损伤。与F组比较,M、H组大鼠体重、Lee`s指数降低、血清LDL、FFA含量降低(P<0.01);心肌AMPK、MCD、CPT-1蛋白表达增加,比目鱼肌AMPK、MCD蛋白表达增加(P<0.05),超微结构损伤减轻。与M组比较,H组大鼠血清HDL含量增加(P<0.01),心肌AMPK、MCD蛋白表达增加,超微结构损伤较轻;比目鱼肌AMPK蛋白表达降低,MCD蛋白表达增加(P<0.05),超微结构损伤较重。结论:MICT与HIIT可通过干预AMPK、MCD、CPT-1蛋白表达,对高脂膳食大鼠心肌和比目鱼肌超微结构产生不同影响。展开更多
文摘Malonyl-CoA synthetases may modulate cell responses to abiotic stress by regulating stress-related signaling transduction pathways or activating expression of transcription factors.However,the molecular mechanism of cold stress tolerance enhanced by malonyl-CoA synthetase is not fully understood.Here,we report that overexpression of the Arabidopsis thaliana malonyl-CoA synthetase gene AAE13.1 resulted in increased cell viability and growth rate and decreased thiobarbituric acid reactive substances under cold stress in rice(Oryza sativa L.),tobacco(Nicotiana tabacum),and slash pine(Pinus elliottii Engelm.).AAE13.1 was associated with cold stress tolerance by increasing the activity of ascorbate peroxidase,catalase,polyphenol oxidase,and peroxidase and the accumulation of acid phosphatase and alkaline phosphatase.Among six rice mitogenactivated protein kinase(MAPK)genes examined,AAE13.1 overexpression increased the expression of OsMAPK genes during cold stress.AAE13.1 activated expression of stressresponse genes OsMAPK1,OsMAPK2,and OsMAPK3,indicating that AAE13.1 enhances cold stress tolerance by regulating expression of MAPK genes in plant cells.These results increase our understanding of cold stress tolerance in species of monocotyledons,dicotyledons,and gymnosperms.
文摘The full-length genomic DNA of MCAT (Malonyl-CoA:acyl carrier protein transacylase) in Brassica napus was cloned. BnMCAT shares very high identity with AtMCAT in gene sequence and gene structure. A multiple alignment of the protein sequence showed that BnMCAT shares high identity with other MCATs from E. coli and plants. BnMCAT was expressed in all tissues, such as roots, stems, leaves, flowers, and seeds, and no significant differences in the expression level were found in different embryo stages after pollination. According to an in vitro relative activity analysis, purified recombinant BnMCAT expressed in E. coli had transacylase activity. Although the relative activities of BnMCAT in crude extracts isolated from different staged embryos were similar and showed little variation, a higher relative activity was found in a crude extract isolated from embryos in comparison to leaves. Different relative activities of BnMCAT in crude extracts isolated from cultivars with different oil content were also found, suggesting that the activity of BnMCAT might be a decisive factor for a high oil content. Together, these results showed that BnMCAT is an important enzyme in the FAS system and indicate that BnMCAT might be a new target enzyme for future crop improvement through genetic engineering.
文摘Aim Malonyl-CoA is regarded as a key signaling molecule in mammalian ceils. It is converted to acetyl-CoA, and to a lesser extent, to malonyl acid and malonylcamitine （C3DC）. Availability of carnitine has been reported to be essential for the developing fetus. The objectives of the present study were to analyze associations of malonylcarnitine, acetylcarnitine （C2）, and free carnitine （CO） in subjects with orofacial clefts. Methodology We performed a retrospective analysis of carnitine concentration obtained from a newborn screening program carried out in our institution. Concentrations of whole blood malonylcarnitine, acetylcarnitine, and free carnitine were measured using tandem mass spectrometry. The study group consisted of 51 children with nonsyndromic cleft lip with or without cleft palate. In total, 106 healthy children without congenital anomalies served as controls. Cut-off points were established using likeli-hood ratio values. Results The mean concentration of malonylcarnitine in the cleft group was lower than that of the control group, 0.048 μmol.L^1 vs. 0.058 μmol.L^-1, respectively （P=-0.009）. In patients with orofacial cleft, low malonylcarnitine levels （〈0.047 μmol.L-1） were 1.7 times more predominant than in healthy individuals （P=-0.03）. The mean concentration of acetylcarnitine was also lower in affected newborns in comparison to controls, 33.8 μol.L^-1 vs. 37.8 μmol·L^-1, respectively （P=-0.026）. After analysis of acetylearnitine and free carnitine concentrations, the likelihood ratio test did not indicate valuable cut-offpoints. Conclusion The study provides initial data indicating a potential association between decreased malonylcarnitine and abnormal palatogenesis.
文摘目的:观察中等强度持续运动(MICT)与高强度间歇运动(HIIT)对高脂膳食大鼠心肌和比目鱼肌超微结构的影响并探讨其机制。方法:5周龄雄性SD大鼠随机分为普通膳食安静组(C)、高脂膳食安静组(F)、高脂膳食MICT组(M)和高脂膳食HIIT组(H),每组8只,高脂膳食饲料脂肪含量为45%。M和H组进行12周坡度为25°的跑台运动,M组进行70%VO_(2)max强度的持续运动,H组进行以5 min 40%~45%VO_(2)max和4 min 95%~99%VO_(2)max强度依次交替的间歇运动。干预结束后检测血清FFA、TG、HDL、LDL含量;透射电镜观察大鼠心肌和比目鱼肌超微结构;Western blot检测心肌和比目鱼肌AMPK、MCD及CPT-1的蛋白表达。结果:与C组比较,F组大鼠体重、Lee`s指数、血清LDL、TG和FFA含量均增加,HDL含量降低(P<0.05);心肌和比目鱼肌AMPK、CPT-1蛋白表达升高,MCD蛋白表达降低(P<0.05),超微结构损伤。与F组比较,M、H组大鼠体重、Lee`s指数降低、血清LDL、FFA含量降低(P<0.01);心肌AMPK、MCD、CPT-1蛋白表达增加,比目鱼肌AMPK、MCD蛋白表达增加(P<0.05),超微结构损伤减轻。与M组比较,H组大鼠血清HDL含量增加(P<0.01),心肌AMPK、MCD蛋白表达增加,超微结构损伤较轻;比目鱼肌AMPK蛋白表达降低,MCD蛋白表达增加(P<0.05),超微结构损伤较重。结论:MICT与HIIT可通过干预AMPK、MCD、CPT-1蛋白表达,对高脂膳食大鼠心肌和比目鱼肌超微结构产生不同影响。
