食物泡是原生动物把食物纳入细胞内形成的临时细胞器,食物泡形成后在细胞质中沿一定路线运行流动,并与初级溶酶体结合形成次级溶酶体（食物泡）,对食物进行消化并吸收营养物质。食物泡中的食物残渣最后通过胞肛排出体外。从食物泡的产...食物泡是原生动物把食物纳入细胞内形成的临时细胞器,食物泡形成后在细胞质中沿一定路线运行流动,并与初级溶酶体结合形成次级溶酶体（食物泡）,对食物进行消化并吸收营养物质。食物泡中的食物残渣最后通过胞肛排出体外。从食物泡的产生到消失,有泡内液体p H的降低（p H 3~4）和再上升（p H约8）的变化。在观察草履虫实验中一般采用中性红（变色范围6.4~8.0,由红变黄）乙醇染液来观察食物泡的消化过程。根据相应的颜色反应来判断pH的变化。展开更多
OBJECTIVE: To investigate the direct effects of the Flt3 ligand (FL) on hematopoiesis, such as the stimulation of the formation of hematopoietic colonies and the proliferation of dendritic cells, as well as the indire...OBJECTIVE: To investigate the direct effects of the Flt3 ligand (FL) on hematopoiesis, such as the stimulation of the formation of hematopoietic colonies and the proliferation of dendritic cells, as well as the indirect stimulation of hematopoiesis, especially via the proliferation of endothelial cells. METHODS: Mononuclear cells from human cord blood were plated in methylcellulose medium containing different cytokines to induce hematopoietic colony formation. Dendritic cells (DCs) were induced from the mononuclear cells with a cytokine cocktail with or without recombinant human soluble FL (rhFL; 100 ng/ml). The Flt3 receptors on the surface of a human microvascular endothelial cell line (ECV) were analyzed by flow cytometry. The proliferation of ECV stimulated by rhFL was measured with the microculture tetrazolium assay. The levels of FL, IL-6, IL-8, G-CSF and GM-CSF in the supernatant of ECV cultures were measured by enzyme linked immunoabsorbent assay (ELISA). RESULTS: rhFL stimulates colony formation from cord blood when used as a sole stimulant. FL in combination with other cytokines increased colony formation significantly. The number of DCs was approximately 2.5 times higher when rhFL was used. rhFL stimulates the proliferation of ECV on which Flt3 receptors are expressed. Furthermore, ECV secretes FL, IL-6, IL-8, G-CSF and GM-CSF, which were augmented by tumor necrosis factor-alpha and rhFL. CONCLUSIONS: rhFL enhances hematopoietic colony formation and DC proliferation from human cord blood cells. FL not only stimulates the proliferation of ECV, but is also secreted by ECV. FL may exert direct and indirect effects on hematopoiesis.展开更多
文摘食物泡是原生动物把食物纳入细胞内形成的临时细胞器,食物泡形成后在细胞质中沿一定路线运行流动,并与初级溶酶体结合形成次级溶酶体（食物泡）,对食物进行消化并吸收营养物质。食物泡中的食物残渣最后通过胞肛排出体外。从食物泡的产生到消失,有泡内液体p H的降低（p H 3~4）和再上升（p H约8）的变化。在观察草履虫实验中一般采用中性红（变色范围6.4~8.0,由红变黄）乙醇染液来观察食物泡的消化过程。根据相应的颜色反应来判断pH的变化。
基金agrantfromtheIAEAFoundationfortheProtectionofAcuteIrradiationInjury (No CPR/9/0 2 5 )
文摘OBJECTIVE: To investigate the direct effects of the Flt3 ligand (FL) on hematopoiesis, such as the stimulation of the formation of hematopoietic colonies and the proliferation of dendritic cells, as well as the indirect stimulation of hematopoiesis, especially via the proliferation of endothelial cells. METHODS: Mononuclear cells from human cord blood were plated in methylcellulose medium containing different cytokines to induce hematopoietic colony formation. Dendritic cells (DCs) were induced from the mononuclear cells with a cytokine cocktail with or without recombinant human soluble FL (rhFL; 100 ng/ml). The Flt3 receptors on the surface of a human microvascular endothelial cell line (ECV) were analyzed by flow cytometry. The proliferation of ECV stimulated by rhFL was measured with the microculture tetrazolium assay. The levels of FL, IL-6, IL-8, G-CSF and GM-CSF in the supernatant of ECV cultures were measured by enzyme linked immunoabsorbent assay (ELISA). RESULTS: rhFL stimulates colony formation from cord blood when used as a sole stimulant. FL in combination with other cytokines increased colony formation significantly. The number of DCs was approximately 2.5 times higher when rhFL was used. rhFL stimulates the proliferation of ECV on which Flt3 receptors are expressed. Furthermore, ECV secretes FL, IL-6, IL-8, G-CSF and GM-CSF, which were augmented by tumor necrosis factor-alpha and rhFL. CONCLUSIONS: rhFL enhances hematopoietic colony formation and DC proliferation from human cord blood cells. FL not only stimulates the proliferation of ECV, but is also secreted by ECV. FL may exert direct and indirect effects on hematopoiesis.
