Pleshinger J, Weidner E
J Cell Biol. 1985 Jun;100(6):1834-8. doi: 10.1083/jcb.100.6.1834.
The microsporidian spore extrusion apparatus activates with a calcium influx from Spraguea lophii spore wall/plasma membrane; this influx requires preconditioning with an extrasporular shift in medium pH to the alkaline in the presence of the polyanions mucin or polyglutamate. Undischarged S. lophii spores display calcium bound to the wall/plasma membrane with a characteristic calcium-chlorotetracycline fluorescence; this fluorescence declines significantly during spore discharge. S. lophii spores do not discharge when spore wall/plasma membrane calcium is removed with EGTA. Extrasporular mucin or polyglutamate and a pH shift to the alkaline appear to be necessary preconditions for the triggering of the influx of spore wall/plasma membrane-bound 45Ca2+. Ionophore A-23187 also effectively activates spore discharge without other extrasporular polyanions. Micromolar concentrations of the calcium antagonists lanthanum or verapamil prevent spore discharge, and micromolar concentrations of calmodulin inhibitors chlorpromazine and trifluroperazine prevent spore discharge. Calmodulin, visualized with a calmodulin antibody and a peroxidase conjugate, is localized particularly on the plasma membrane and the polaroplast membranes of the extrusion apparatus.
微孢子虫的孢子挤出装置会随着来自嗜鱼外瓶霉孢子壁/质膜的钙离子内流而激活；这种内流需要在存在多阴离子粘蛋白或聚谷氨酸的情况下，将培养基的细胞外pH值转变为碱性来进行预处理。未排出的嗜鱼外瓶霉孢子显示出与壁/质膜结合的钙，具有特征性的钙-氯四环素荧光；这种荧光在孢子排出过程中显著下降。当用乙二醇双（2-氨基乙基醚）四乙酸（EGTA）去除孢子壁/质膜钙时，嗜鱼外瓶霉孢子不会排出。细胞外粘蛋白或聚谷氨酸以及pH值转变为碱性似乎是触发孢子壁/质膜结合的45Ca2+内流的必要前提条件。离子载体A-23187在没有其他细胞外多阴离子的情况下也能有效地激活孢子排出。微摩尔浓度的钙拮抗剂镧或维拉帕米可阻止孢子排出，微摩尔浓度的钙调蛋白抑制剂氯丙嗪和三氟拉嗪也可阻止孢子排出。用钙调蛋白抗体和过氧化物酶偶联物可视化的钙调蛋白特别定位于挤出装置的质膜和极质体膜上。
