为了能直观反映大麦生长发育进程，利用生理发育时问恒定的原理，建立了系统预测大麦顶端发育阶段和物候期的模拟模型。模型的检验结果表明，模型对大麦大多数发育阶段的绝对模拟误差都在0～6d，平均差平方和的根值（Root mean square e...为了能直观反映大麦生长发育进程，利用生理发育时问恒定的原理，建立了系统预测大麦顶端发育阶段和物候期的模拟模型。模型的检验结果表明，模型对大麦大多数发育阶段的绝对模拟误差都在0～6d，平均差平方和的根值（Root mean square error，RMSE）不超过4d。模型对出苗期、成熟期的模拟误差较小，RMSE分别为1．0和1．6d；对雌雄蕊分化期的模拟误差较大,RMSE为3．7d；对于比较重要的单棱期和药隔形成期，RMSE分别为1．8和3．2d，均没有超过4d。模型表现出较强的机理性和实用性。展开更多
Understanding limb development not only gives insights into the outgrowth and differentiation of the limb,but also has clinical relevance.Limb development begins with two paired limb buds(forelimb and hindlimb buds),w...Understanding limb development not only gives insights into the outgrowth and differentiation of the limb,but also has clinical relevance.Limb development begins with two paired limb buds(forelimb and hindlimb buds),which are initially undifferentiated mesenchymal cells tipped with a thickening of the ectoderm,termed the apical ectodermal ridge(AER).As a transitional embryonic structure,the AER undergoes four stages and contributes to multiple axes of limb development through the coordination of signalling centres,feedback loops,and other cell ac-tivities by secretory signalling and the activation of gene expression.Within the scope of proximodistal pattering,it is understood that while fibroblast growth factors(FGFs)function sequentially over time as primary components of the AER signalling process,there is still no consensus on models that would explain proximodistal patterning itself.In anteroposterior pattermning,the AER has a dual-direction regulation by which it promotes the sonic hedgehog(Shh)gene expression in the zone of polarizing activity(ZPA)for proliferation,and inhibits Shh expression in the anterior mesenchyme.In dorsoventral patterming,the AER activates Engrailed-1(En1)expression,and thus represses Wnt family member 7a(Wnt7a)expression in the ventral ectoderm by the expression of Fgfs,Sp6/8,and bone morpho-genetic protein(Bmp)genes.The AER also plays a vital role in shaping the individual digits,since levels of Fgf4/8 and Bmps expressed in the AER affect digit patterning by controlling apoptosis.In summary,the knowledge of crosstalk within AER among the three main axes is essential to understand limb growth and pattern fomation,as the development of its areas proceeds simultaneously.展开更多
During plant development, the frequency and context of cell division must be controlled, and cells must differentiate properly to perform their mature functions. In addition, stem cell niches need to be maintained as ...During plant development, the frequency and context of cell division must be controlled, and cells must differentiate properly to perform their mature functions. In addition, stem cell niches need to be maintained as a reservoir for new cells. All of these processes require intercellular signaling, whether it is a cell relaying its position to other cells, or more mature cells signaling to the stem cell niche to regulate the rate of growth. Receptor-like kinases have emerged as a major component in these diverse roles, especially within the Arabidopsis root. In this review, the functions of receptor-like kinase signaling in regulating Arabidopsis root development will be examined in theareas of root apical meristem maintenance, regulation of epidermal cell fate, lateral root development and vascular differentiation.展开更多
Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissecte...Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.展开更多
文摘为了能直观反映大麦生长发育进程，利用生理发育时问恒定的原理，建立了系统预测大麦顶端发育阶段和物候期的模拟模型。模型的检验结果表明，模型对大麦大多数发育阶段的绝对模拟误差都在0～6d，平均差平方和的根值（Root mean square error，RMSE）不超过4d。模型对出苗期、成熟期的模拟误差较小，RMSE分别为1．0和1．6d；对雌雄蕊分化期的模拟误差较大,RMSE为3．7d；对于比较重要的单棱期和药隔形成期，RMSE分别为1．8和3．2d，均没有超过4d。模型表现出较强的机理性和实用性。
基金Key Research and Development Project of Shandong Province(No.2017G006043),China。
文摘Understanding limb development not only gives insights into the outgrowth and differentiation of the limb,but also has clinical relevance.Limb development begins with two paired limb buds(forelimb and hindlimb buds),which are initially undifferentiated mesenchymal cells tipped with a thickening of the ectoderm,termed the apical ectodermal ridge(AER).As a transitional embryonic structure,the AER undergoes four stages and contributes to multiple axes of limb development through the coordination of signalling centres,feedback loops,and other cell ac-tivities by secretory signalling and the activation of gene expression.Within the scope of proximodistal pattering,it is understood that while fibroblast growth factors(FGFs)function sequentially over time as primary components of the AER signalling process,there is still no consensus on models that would explain proximodistal patterning itself.In anteroposterior pattermning,the AER has a dual-direction regulation by which it promotes the sonic hedgehog(Shh)gene expression in the zone of polarizing activity(ZPA)for proliferation,and inhibits Shh expression in the anterior mesenchyme.In dorsoventral patterming,the AER activates Engrailed-1(En1)expression,and thus represses Wnt family member 7a(Wnt7a)expression in the ventral ectoderm by the expression of Fgfs,Sp6/8,and bone morpho-genetic protein(Bmp)genes.The AER also plays a vital role in shaping the individual digits,since levels of Fgf4/8 and Bmps expressed in the AER affect digit patterning by controlling apoptosis.In summary,the knowledge of crosstalk within AER among the three main axes is essential to understand limb growth and pattern fomation,as the development of its areas proceeds simultaneously.
文摘During plant development, the frequency and context of cell division must be controlled, and cells must differentiate properly to perform their mature functions. In addition, stem cell niches need to be maintained as a reservoir for new cells. All of these processes require intercellular signaling, whether it is a cell relaying its position to other cells, or more mature cells signaling to the stem cell niche to regulate the rate of growth. Receptor-like kinases have emerged as a major component in these diverse roles, especially within the Arabidopsis root. In this review, the functions of receptor-like kinase signaling in regulating Arabidopsis root development will be examined in theareas of root apical meristem maintenance, regulation of epidermal cell fate, lateral root development and vascular differentiation.
基金supported by National Nature Science Foundation of China(Project No.3057 2046,30725042)
文摘Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.
