The purpose of this study was to investigate the morphology, transmission route of photosynthetic products in the seed stalk of Caragana arborescens Lam. at various stages after flowering and evaluate the role of the ...The purpose of this study was to investigate the morphology, transmission route of photosynthetic products in the seed stalk of Caragana arborescens Lam. at various stages after flowering and evaluate the role of the seed stalk in seed maturation using scanning electron microscopy. We found that the mature seed stalk mainly consisted of vessels,sclerenchymatous cells and parenchymatous cells. Elongated cells formed a ring at the junction between the seed stalk and seed, and a large hollow was produced by two layers of sclerenchymatous cells in the interior seed, which functions to sustain seed growth. The opening in the center of the ring was closed during an early stage of seed development, and the opening enlarged as the seed matured.There were two routes for material transport, which started from the seed stalk： one from the seed coat to the embryo,and another directly entering the embryo. Vessels, which are abundant in the seed stalk, are the pathway for absorption of nutrients by the seeds. The vessels were densely packed in the seed stalk, and secondary thickening of the cell wall of the vessels was characterized by net thread thickening, while the secondary thickening of the cell wall of the vessels within the seed was characterized by screw thread thickening. The morphological characteristics of the vessels were adaptive to its functions.展开更多
Bone morphogenic protein 4（BMP4） belongs into the transforming growth factor-β（TGF-β） superfamily.BMP4 was originally discovered to par- ticipate in embryonic development,bone and cartilage formation.BMP4 is up-...Bone morphogenic protein 4（BMP4） belongs into the transforming growth factor-β（TGF-β） superfamily.BMP4 was originally discovered to par- ticipate in embryonic development,bone and cartilage formation.BMP4 is up-regulated in calcified atherosclerotic plaques and reduces endothelium-de-pendent relaxations.BMP4 can stimulate superoxide production and exert pro-inflammatory effects on the endothelium.The underlying mechanisms of how BMP4 mediates endothelial dysfunction and hypertension remain to be elucidated.Our recent study shows that BMP treatment led to the impaired en-dothelium -dependent relaxations（EDR）,exaggerated endothelium-dependent contractions（EDC） and reactive oxygen species（ROS） generation in mouse aortas,which were reversed by BMP4 antagonist noggin.Pharmacological inhibition with thromboxane-prostanoid receptor antagonist or cyclooxygenase-2 （COX-2） but not cyclooxygenase-1（COX-1） inhibitor attenuates the BMP4-induced endothelial dysfunction which was further confirmed with the use of COX-1<sup>-/-</sup> or COX-2<sup>-/-</sup> mice.Noggin and knockdown of BMP receptor 1A abolished EDC and COX-2 up-regulation in BMP4-treated mouse aortas. Apocynin and tempol treatment were effective in restoring EDR,preventing EDC,eliminating ROS over-production and COX-2 over-expression in BMP4-treated aortae.COX-2 inhibition blocked the effect of BMP4 without affecting BMP4-induced ROS over-production and COX-2 up-regulation.Significantly, renal arteries from hypertensive rats and humans showed higher levels of COX-2 and BMP4 accompanied by endothelial dysfunction.We show for the first time that ROS serve as a pathological link between BMP4 stimulation and the downstream COX-2 up-regulation in endothelial cells,leading to endothelial dysfunction.This BMP4/ROS/COX-2 cascade is important in the maintenance of endothelial dysfunction in hypertension.展开更多
基金supported by National Natural Science Foundation of China(Grant No.31600364)
文摘The purpose of this study was to investigate the morphology, transmission route of photosynthetic products in the seed stalk of Caragana arborescens Lam. at various stages after flowering and evaluate the role of the seed stalk in seed maturation using scanning electron microscopy. We found that the mature seed stalk mainly consisted of vessels,sclerenchymatous cells and parenchymatous cells. Elongated cells formed a ring at the junction between the seed stalk and seed, and a large hollow was produced by two layers of sclerenchymatous cells in the interior seed, which functions to sustain seed growth. The opening in the center of the ring was closed during an early stage of seed development, and the opening enlarged as the seed matured.There were two routes for material transport, which started from the seed stalk： one from the seed coat to the embryo,and another directly entering the embryo. Vessels, which are abundant in the seed stalk, are the pathway for absorption of nutrients by the seeds. The vessels were densely packed in the seed stalk, and secondary thickening of the cell wall of the vessels was characterized by net thread thickening, while the secondary thickening of the cell wall of the vessels within the seed was characterized by screw thread thickening. The morphological characteristics of the vessels were adaptive to its functions.
文摘Bone morphogenic protein 4（BMP4） belongs into the transforming growth factor-β（TGF-β） superfamily.BMP4 was originally discovered to par- ticipate in embryonic development,bone and cartilage formation.BMP4 is up-regulated in calcified atherosclerotic plaques and reduces endothelium-de-pendent relaxations.BMP4 can stimulate superoxide production and exert pro-inflammatory effects on the endothelium.The underlying mechanisms of how BMP4 mediates endothelial dysfunction and hypertension remain to be elucidated.Our recent study shows that BMP treatment led to the impaired en-dothelium -dependent relaxations（EDR）,exaggerated endothelium-dependent contractions（EDC） and reactive oxygen species（ROS） generation in mouse aortas,which were reversed by BMP4 antagonist noggin.Pharmacological inhibition with thromboxane-prostanoid receptor antagonist or cyclooxygenase-2 （COX-2） but not cyclooxygenase-1（COX-1） inhibitor attenuates the BMP4-induced endothelial dysfunction which was further confirmed with the use of COX-1<sup>-/-</sup> or COX-2<sup>-/-</sup> mice.Noggin and knockdown of BMP receptor 1A abolished EDC and COX-2 up-regulation in BMP4-treated mouse aortas. Apocynin and tempol treatment were effective in restoring EDR,preventing EDC,eliminating ROS over-production and COX-2 over-expression in BMP4-treated aortae.COX-2 inhibition blocked the effect of BMP4 without affecting BMP4-induced ROS over-production and COX-2 up-regulation.Significantly, renal arteries from hypertensive rats and humans showed higher levels of COX-2 and BMP4 accompanied by endothelial dysfunction.We show for the first time that ROS serve as a pathological link between BMP4 stimulation and the downstream COX-2 up-regulation in endothelial cells,leading to endothelial dysfunction.This BMP4/ROS/COX-2 cascade is important in the maintenance of endothelial dysfunction in hypertension.
