Background: The high power output necessary for insect flight has driven the evolution of muscles with large myofibrils (primary energy consumers) and abundant mitochondria (primary energy suppliers). The intricate fu...Background: The high power output necessary for insect flight has driven the evolution of muscles with large myofibrils (primary energy consumers) and abundant mitochondria (primary energy suppliers). The intricate functional interrelationship between these two organelles remains largely unknown despite its fundamental importance in understanding insect flight bioenergetics. Unlike vertebrate muscle that relies on a phosphagen (creatine phosphate/creatine kinase) system to regulate high energy phosphate flux, insect flight muscle has been reported to lack mitochondrial arginine kinase (analogous to creatine kinase), a key enzyme that enables intracellular energy transport. Creatine kinase is known to interact with mitochondrial adenine nucleotide translocase (ANT) in the transfer of ADP and ATP into and out of the mitochondria. Results: Here, we use quantitative immunogold transmission electron microscopy to show that in Drosophila melanogaster indirect flight muscles (IFM), ANT is present in the mitochondria as well as throughout the myofibril. To confirm this unexpected result, we created a transgenic line that expresses a chimeric GFP-ANT protein and used an anti-GFP antibody to determine the intracellular distribution of the fusion protein in the IFM. Similar to results obtained with anti-ANT, the fusion GFP-ANT protein is detected in myofibrils and mitochondria. We confirmed the absence of arginine kinase from IFM mitochondria and show that its sarcomeric (i.e., intramyofibrillar) distribution is similar to that of ANT. Conclusions: These results raise the possibility that direct channeling of nucleotides between mitochondria and myofibrils is assisted by an ANT protein thereby circumventing the need for a phosphagen shuttle in the IFM. The myofibrillar ANT may represent a unique adaptation in the muscles that require efficient exchange of nucleotides between mitochondria and myofibrils.展开更多
Successful completion of spermatogenesis is crucial for the perpetuation of the species.In Drosophila,spermatid individualization,a process involving changes in mitochondrial structure and function is critical to prod...Successful completion of spermatogenesis is crucial for the perpetuation of the species.In Drosophila,spermatid individualization,a process involving changes in mitochondrial structure and function is critical to produce functional mature sperm.Ant2,encoding a mitochondrial adenine nucleotide translocase,is highly expressed in male testes and plays a role in energy metabolism in the mitochondria.However,its molecular function remains unclear.Here,we identified an important role of Ant2 in spermatid individualization.In Ant2 knockdown testes,spermatid individualization complexes composed of F-actin cones exhibited a diffuse distribution,and mature sperms were absent in the seminal vesicle,thus leading to male sterility.The most striking effects in Ant2-knockdown spermatids were decrease in tubulin polyglycylation and disruption of proper mitochondria derivatives function.Excessive apoptotic cells were also observed in Ant2-knockdown testes.To further investigate the phenotype of Ant2 knockdown in testes at the molecular level,complementary transcriptome and proteome analyses were performed.At the mRNA level,868 differentially expressed genes were identified,of which 229 genes were upregulated and 639 were downregulated induced via Ant2 knockdown.iTRAQ-labeling proteome analysis revealed 350 differentially expressed proteins,of which 117 proteins were upregulated and 233 were downregulated.The expression of glutathione transferase(GstD5,GstE5,GstE8,and GstD3),proteins involved in reproduction were significantly regulated at both the mRNA and protein levels.These results indicate that Ant2 is crucial for spermatid maturation by affecting mitochondrial morphogenesis.展开更多
目的研究黄芪总黄酮对肝硬化大鼠肝组织脂肪酸转位酶(FAT)和环氧化酶2表达水平的影响。方法将53只SD大鼠随机分为正常组10只和肝硬化组43只,给予二甲基亚硝胺(DMN)腹腔注射4周造模。在实验第3周,将造模组大鼠随机分为模型组14只和黄芪...目的研究黄芪总黄酮对肝硬化大鼠肝组织脂肪酸转位酶(FAT)和环氧化酶2表达水平的影响。方法将53只SD大鼠随机分为正常组10只和肝硬化组43只,给予二甲基亚硝胺(DMN)腹腔注射4周造模。在实验第3周,将造模组大鼠随机分为模型组14只和黄芪总黄酮治疗组(小剂量组14只和大剂量组15只),治疗组给予相应剂量的药物灌胃4周。在实验结束时,处死大鼠,取肝组织行天狼猩红染色,部分肝组织抽提总RNA,采用Real time PCR法检测目标m RNA水平;采用Western blot法检测目标蛋白表达水平。结果模型组大鼠肝组织胶原增多,而治疗组胶原纤维明显下降;模型组FAT m RNA为(0.098±0.08),蛋白为(1.05±0.076),而小剂量黄芪总黄酮治疗组分别为(0.58±0.04)和(0.67±0.021),大剂量组分别为(0.45±0.07)和[(0.31±0.072),P均<0.01];模型组环氧化酶2 m RNA为(0.78±0.044),蛋白为(1.48±0.13),而小剂量黄芪总黄酮治疗组分别为(0.52±0.010)和(1.24±0.11),大剂量黄芪总黄酮治疗组分别为(0.28±0.049)和[(0.68±0.09),P均<0.01]。结论黄芪总黄酮发挥抗大鼠肝纤维化作用可能与抑制脂肪酸转位酶和环氧化酶2表达有关。展开更多
文摘Background: The high power output necessary for insect flight has driven the evolution of muscles with large myofibrils (primary energy consumers) and abundant mitochondria (primary energy suppliers). The intricate functional interrelationship between these two organelles remains largely unknown despite its fundamental importance in understanding insect flight bioenergetics. Unlike vertebrate muscle that relies on a phosphagen (creatine phosphate/creatine kinase) system to regulate high energy phosphate flux, insect flight muscle has been reported to lack mitochondrial arginine kinase (analogous to creatine kinase), a key enzyme that enables intracellular energy transport. Creatine kinase is known to interact with mitochondrial adenine nucleotide translocase (ANT) in the transfer of ADP and ATP into and out of the mitochondria. Results: Here, we use quantitative immunogold transmission electron microscopy to show that in Drosophila melanogaster indirect flight muscles (IFM), ANT is present in the mitochondria as well as throughout the myofibril. To confirm this unexpected result, we created a transgenic line that expresses a chimeric GFP-ANT protein and used an anti-GFP antibody to determine the intracellular distribution of the fusion protein in the IFM. Similar to results obtained with anti-ANT, the fusion GFP-ANT protein is detected in myofibrils and mitochondria. We confirmed the absence of arginine kinase from IFM mitochondria and show that its sarcomeric (i.e., intramyofibrillar) distribution is similar to that of ANT. Conclusions: These results raise the possibility that direct channeling of nucleotides between mitochondria and myofibrils is assisted by an ANT protein thereby circumventing the need for a phosphagen shuttle in the IFM. The myofibrillar ANT may represent a unique adaptation in the muscles that require efficient exchange of nucleotides between mitochondria and myofibrils.
基金supported by China Agriculture Research System of MOF and MARA(CARS-18-SYZ10)Hubei Province Agricultural Science and Technology Innovation Center Project(2021-620-000-001-009)Hubei Province Key Research and Development Project(2022BBA0079).
文摘Successful completion of spermatogenesis is crucial for the perpetuation of the species.In Drosophila,spermatid individualization,a process involving changes in mitochondrial structure and function is critical to produce functional mature sperm.Ant2,encoding a mitochondrial adenine nucleotide translocase,is highly expressed in male testes and plays a role in energy metabolism in the mitochondria.However,its molecular function remains unclear.Here,we identified an important role of Ant2 in spermatid individualization.In Ant2 knockdown testes,spermatid individualization complexes composed of F-actin cones exhibited a diffuse distribution,and mature sperms were absent in the seminal vesicle,thus leading to male sterility.The most striking effects in Ant2-knockdown spermatids were decrease in tubulin polyglycylation and disruption of proper mitochondria derivatives function.Excessive apoptotic cells were also observed in Ant2-knockdown testes.To further investigate the phenotype of Ant2 knockdown in testes at the molecular level,complementary transcriptome and proteome analyses were performed.At the mRNA level,868 differentially expressed genes were identified,of which 229 genes were upregulated and 639 were downregulated induced via Ant2 knockdown.iTRAQ-labeling proteome analysis revealed 350 differentially expressed proteins,of which 117 proteins were upregulated and 233 were downregulated.The expression of glutathione transferase(GstD5,GstE5,GstE8,and GstD3),proteins involved in reproduction were significantly regulated at both the mRNA and protein levels.These results indicate that Ant2 is crucial for spermatid maturation by affecting mitochondrial morphogenesis.
文摘目的研究黄芪总黄酮对肝硬化大鼠肝组织脂肪酸转位酶(FAT)和环氧化酶2表达水平的影响。方法将53只SD大鼠随机分为正常组10只和肝硬化组43只,给予二甲基亚硝胺(DMN)腹腔注射4周造模。在实验第3周,将造模组大鼠随机分为模型组14只和黄芪总黄酮治疗组(小剂量组14只和大剂量组15只),治疗组给予相应剂量的药物灌胃4周。在实验结束时,处死大鼠,取肝组织行天狼猩红染色,部分肝组织抽提总RNA,采用Real time PCR法检测目标m RNA水平;采用Western blot法检测目标蛋白表达水平。结果模型组大鼠肝组织胶原增多,而治疗组胶原纤维明显下降;模型组FAT m RNA为(0.098±0.08),蛋白为(1.05±0.076),而小剂量黄芪总黄酮治疗组分别为(0.58±0.04)和(0.67±0.021),大剂量组分别为(0.45±0.07)和[(0.31±0.072),P均<0.01];模型组环氧化酶2 m RNA为(0.78±0.044),蛋白为(1.48±0.13),而小剂量黄芪总黄酮治疗组分别为(0.52±0.010)和(1.24±0.11),大剂量黄芪总黄酮治疗组分别为(0.28±0.049)和[(0.68±0.09),P均<0.01]。结论黄芪总黄酮发挥抗大鼠肝纤维化作用可能与抑制脂肪酸转位酶和环氧化酶2表达有关。
