Loeb Marcia J
Insect Biocontrol Laboratory, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA.
Arch Insect Biochem Physiol. 2005 Aug;59(4):202-10. doi: 10.1002/arch.20060.
Cultured stem cells from larval midgut tissue of the lepidopteran Heliothis virescens respond to alterations in external calcium ion concentration (Ca(2+) (out)) by changing the rate of stem cell proliferation and by differentiating to larval or non-larval phenotypes. Decreasing the external concentration of Ca(2+) with the Ca(2+) chelating agent EGTA increased proliferation of stem cells in culture, and doubled the proportion of cells differentiating to columnar and goblet cells typical of larval midgut compared to controls. In contrast, increasing inward transport of Ca(2+) into the cells by increasing the concentration of external calcium ion concentration, or by incubation with the Ca(2+) ionophore A23187 (which tends to open inward plasma membrane Ca(2+) channels), induced dose-dependent differentiation to non-midgut cell types such as squamous and scale-like cells. However, the latter treatments did not significantly alter stem cell proliferation or differentiation to normal larval midgut epithelium.
从鳞翅目昆虫烟草天蛾幼虫中肠组织培养的干细胞，通过改变干细胞增殖速率以及分化为幼虫或非幼虫表型，来响应外部钙离子浓度（Ca(2+) (out)）的变化。用钙离子螯合剂乙二醇双四乙酸（EGTA）降低外部Ca(2+)浓度，可增加培养中干细胞的增殖，与对照组相比，分化为幼虫中肠典型柱状细胞和杯状细胞的细胞比例增加了一倍。相反，通过增加外部钙离子浓度或与钙离子载体A23187（倾向于打开向内的质膜Ca(2+)通道）孵育来增加Ca(2+)向细胞内的转运，会诱导剂量依赖性地分化为非中肠细胞类型，如鳞状细胞和鳞片状细胞。然而，后一种处理并未显著改变干细胞增殖或向正常幼虫中肠上皮的分化。
