The characteristics of high-frequency(HF)electromagnetic(EM)wave propagation can be affected when EM waves propagate in the ionosphere.When ionospheric irregularities appear in the ionosphere,they can have a serious i...The characteristics of high-frequency(HF)electromagnetic(EM)wave propagation can be affected when EM waves propagate in the ionosphere.When ionospheric irregularities appear in the ionosphere,they can have a serious impact on the propagation of HF EM waves.In this study,the propagation of HF EM waves in ionospheric irregularities was investigated by numerical simulation.First,a twodimensional model of plasma bubbles was used to produce ionospheric irregularities in the ionosphere.A ray-tracing method was then utilized to simulate the propagation of HF radio waves in these ionospheric irregularities.Results showed that the propagation of HF radio waves in the ionosphere was more complex in ionospheric irregularities than without ionospheric irregularities.In addition,corresponding ionograms were synthesized by radio rays propagated in the ionosphere with these irregularities.The synthesized ionograms were then compared with the experimental ionograms recorded by an ionosonde.Results showed that spread F could be simulated on the ionograms when ionospheric irregularities occurred in the ionosphere.This result was consistent with the ionosonde observations.展开更多
Recently, kilometer-scale Martian ionospheric irregularities have been measured by the Mars Atmosphere and Volatile EvolutioN(MAVEN) mission(Fowler et al., 2020). In this study, we carried out a simulation of these ir...Recently, kilometer-scale Martian ionospheric irregularities have been measured by the Mars Atmosphere and Volatile EvolutioN(MAVEN) mission(Fowler et al., 2020). In this study, we carried out a simulation of these irregularities, assuming a uniform Martian zonal neutral wind and a cosinusoidal perturbation of the plasma density as the seeding source. Results show that a vertical electric field shear could be induced by such a plasma density perturbation. We find that the vertical electric field shear causes a velocity shear of the plasma between the topside and bottomside ionosphere, which in turn is able to produce kilometer-scale ionospheric irregularities — irregularities of a smaller scale than were seen in previous simulations(Jiang CH et al., 2021). These kilometer-scale variations with altitude, in plasma density and magnetic field profiles, are comparable to the MAVEN observations.展开更多
Eggplant(Solanum melongena L.)is a highly nutritious vegetable.Here,the molecular mechanism of color formation in eggplants was determined using six eggplant cultivars with different peel colors and two SmMYB113-overe...Eggplant(Solanum melongena L.)is a highly nutritious vegetable.Here,the molecular mechanism of color formation in eggplants was determined using six eggplant cultivars with different peel colors and two SmMYB113-overexpressing transgenic eggplants with a purple peel and pulp.Significant differentially expressed genes(DEGs)were identified by RNA-sequencing analysis using the following criteria:log2(sample1/sample2)≥0.75 and q-value≤0.05.Two analytical strategies were used to identify genes related to the different peel color according to the peel color,flavonoids content,delphinidins/flavonoids ratio,and the content of anthocyanins.Finally,27 novel genes were identified to be related to the color difference among eggplant peels and 32 novel genes were identified to be related to anthocyanin biosynthesis and regulated by SmMYB113.Venn analysis revealed that SmCytb5,SmGST,SmMATE,SmASAT3,and SmF3′5’M were shared among both sets of novel genes.Transient expression assay in tobacco suggested that these five genes were not sufficient for inducing anthocyanin biosynthesis alone,but they play important roles in anthocyanin accumulation in eggplant peels.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays indicated that the expression of the five genes could be directly activated by SmMYB113 protein.Finally,a regulatory model for the mechanism of color formation in eggplant was proposed.Overall,the results of this study provide useful information that enhances our understanding of the molecular mechanism underlying the different color formation in eggplant.展开更多
Dentin,the main component of dental hard tissues,is produced by differentiated odontoblasts.How odontoblast differentiation is regulated remains understudied.Here,we screen that the expression of membrane-associated R...Dentin,the main component of dental hard tissues,is produced by differentiated odontoblasts.How odontoblast differentiation is regulated remains understudied.Here,we screen that the expression of membrane-associated RING finger protein 2(March2) is the highest among all March family members,with an increasing trend during odontoblast differentiation.In mouse incisors and molars,MARCH2 is moderately expressed in the undifferentiated dental papilla cells and strongly expressed in the odontoblasts.Knockdown and overexpression experiments demonstrate that MARCH2 inhibits odontoblastic differentiation of mouse dental papilla cells(mDPCs).Additionally,both March2 deficient mice and mice with odontoblast specific knockdown of March2 exhibit the phenotype of increased dentin thickness,accelerated dentin deposition as well as elevated expression levels of odontoblast markers compared with control littermates.Therefore,MARCH2 plays an inhibitory role in odontoblast differentiation.Mechanistically,MARCH2 interacts with protein tyrosine phosphatase receptor delta(PTPRD) and facilitates its K27-linked polyubiquitination and subsequent degradation,which is dependent on the ligase activity of MARCH2.The presence of MARCH2promotes the translocation of PTPRD from the cell membrane to the lysosome,thereby enhancing its degradation via the lysosomal pathway.Further experiments show that knockdown of endogenous Ptprd impairs odontoblastic differentiation of mDPCs.Ptprd and March2 double knockdown in mDPCs apparently reversed the enhanced odontoblastic differentiation by knockdown of March2 alone,indicating that MARCH2 inhibits odontoblastic differentiation by promoting PTPRD degradation.This study unveils a novel mechanism where an E3 ubiquitin ligase regulates odontoblast differentiation through post-translational modification of a membrane protein,highlighting a promising direction for future exploration.展开更多
基金We acknowledge the Institute of Earthquake Forecasting for providing the ionosonde data.This work was supported by the National Natural Science Foundation of China(no.41604133).
文摘The characteristics of high-frequency(HF)electromagnetic(EM)wave propagation can be affected when EM waves propagate in the ionosphere.When ionospheric irregularities appear in the ionosphere,they can have a serious impact on the propagation of HF EM waves.In this study,the propagation of HF EM waves in ionospheric irregularities was investigated by numerical simulation.First,a twodimensional model of plasma bubbles was used to produce ionospheric irregularities in the ionosphere.A ray-tracing method was then utilized to simulate the propagation of HF radio waves in these ionospheric irregularities.Results showed that the propagation of HF radio waves in the ionosphere was more complex in ionospheric irregularities than without ionospheric irregularities.In addition,corresponding ionograms were synthesized by radio rays propagated in the ionosphere with these irregularities.The synthesized ionograms were then compared with the experimental ionograms recorded by an ionosonde.Results showed that spread F could be simulated on the ionograms when ionospheric irregularities occurred in the ionosphere.This result was consistent with the ionosonde observations.
基金supported by the National Natural Science Foundation of China(NSFC No.42074184 and No.41727804)。
文摘Recently, kilometer-scale Martian ionospheric irregularities have been measured by the Mars Atmosphere and Volatile EvolutioN(MAVEN) mission(Fowler et al., 2020). In this study, we carried out a simulation of these irregularities, assuming a uniform Martian zonal neutral wind and a cosinusoidal perturbation of the plasma density as the seeding source. Results show that a vertical electric field shear could be induced by such a plasma density perturbation. We find that the vertical electric field shear causes a velocity shear of the plasma between the topside and bottomside ionosphere, which in turn is able to produce kilometer-scale ionospheric irregularities — irregularities of a smaller scale than were seen in previous simulations(Jiang CH et al., 2021). These kilometer-scale variations with altitude, in plasma density and magnetic field profiles, are comparable to the MAVEN observations.
基金We would like to thank Prof.Daqi Fu(China Agricultural University)for offering pTRV1 and pTRV2 vectors.This work was supported by the Youth Project of Shandong Provincial Natural Science Foundation(grant no.ZR2020QC155)Key Project of Shandong Provincial Natural Science Foundation(grant no.ZR2020KC039)+1 种基金National Natural Sciences Foundations of China(grant no.31672169)the Shandong Provincial Key Research and Development Program(grant no.2022LZGC009).
文摘Eggplant(Solanum melongena L.)is a highly nutritious vegetable.Here,the molecular mechanism of color formation in eggplants was determined using six eggplant cultivars with different peel colors and two SmMYB113-overexpressing transgenic eggplants with a purple peel and pulp.Significant differentially expressed genes(DEGs)were identified by RNA-sequencing analysis using the following criteria:log2(sample1/sample2)≥0.75 and q-value≤0.05.Two analytical strategies were used to identify genes related to the different peel color according to the peel color,flavonoids content,delphinidins/flavonoids ratio,and the content of anthocyanins.Finally,27 novel genes were identified to be related to the color difference among eggplant peels and 32 novel genes were identified to be related to anthocyanin biosynthesis and regulated by SmMYB113.Venn analysis revealed that SmCytb5,SmGST,SmMATE,SmASAT3,and SmF3′5’M were shared among both sets of novel genes.Transient expression assay in tobacco suggested that these five genes were not sufficient for inducing anthocyanin biosynthesis alone,but they play important roles in anthocyanin accumulation in eggplant peels.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays indicated that the expression of the five genes could be directly activated by SmMYB113 protein.Finally,a regulatory model for the mechanism of color formation in eggplant was proposed.Overall,the results of this study provide useful information that enhances our understanding of the molecular mechanism underlying the different color formation in eggplant.
基金supported by grants from the National Natural Science Foundation of China (82370913,82170914 to Guohua Yuan and 82270947 to Guobin Yang)the National Natural Science Foundation of China Key Program (82230029 to Z.C)+1 种基金the Fundamental Research Funds for the Central Universities (2042022dx0003)the Innovation Project of Municipal Science and Technology Bureau (2023020201010170) to Guohua Yuan。
文摘Dentin,the main component of dental hard tissues,is produced by differentiated odontoblasts.How odontoblast differentiation is regulated remains understudied.Here,we screen that the expression of membrane-associated RING finger protein 2(March2) is the highest among all March family members,with an increasing trend during odontoblast differentiation.In mouse incisors and molars,MARCH2 is moderately expressed in the undifferentiated dental papilla cells and strongly expressed in the odontoblasts.Knockdown and overexpression experiments demonstrate that MARCH2 inhibits odontoblastic differentiation of mouse dental papilla cells(mDPCs).Additionally,both March2 deficient mice and mice with odontoblast specific knockdown of March2 exhibit the phenotype of increased dentin thickness,accelerated dentin deposition as well as elevated expression levels of odontoblast markers compared with control littermates.Therefore,MARCH2 plays an inhibitory role in odontoblast differentiation.Mechanistically,MARCH2 interacts with protein tyrosine phosphatase receptor delta(PTPRD) and facilitates its K27-linked polyubiquitination and subsequent degradation,which is dependent on the ligase activity of MARCH2.The presence of MARCH2promotes the translocation of PTPRD from the cell membrane to the lysosome,thereby enhancing its degradation via the lysosomal pathway.Further experiments show that knockdown of endogenous Ptprd impairs odontoblastic differentiation of mDPCs.Ptprd and March2 double knockdown in mDPCs apparently reversed the enhanced odontoblastic differentiation by knockdown of March2 alone,indicating that MARCH2 inhibits odontoblastic differentiation by promoting PTPRD degradation.This study unveils a novel mechanism where an E3 ubiquitin ligase regulates odontoblast differentiation through post-translational modification of a membrane protein,highlighting a promising direction for future exploration.
