烟草培养细胞中钙离子、钙调素与细胞质流的关系

Calcium, Calmodulin and Cytoplasmic Streaming of Tobacco Cultured Cells

烟草愈伤组织的培养细胞中,当钙离子载体将Ca^(2+)导入细胞时,细胞质流停止.CaM拮抗剂试验表明,高钙使细胞质流停止的效应可能与CaM无关,除W7外的多种CaM拮抗剂都明显而且可逆地抑制细胞质流。酶联免疫吸附分析(ELISA)检出培养细胞中存在有CaM。间接酶标免疫组织化学分析进一步证明CaM存在于胞质条纹中。

Using the cultured cells of tobacco callus as a intact cell model, we studied the mechanism of cytoplasmic streaming. The detecting rea- gents included microfilament depolymerizing agent, cytochalasin B; microtubule depoly- merizing agent, colchicine; Ca^(2+) ionophore A 23187; Ca^(2+) chelator EGTA; calmodulin(CaM) antagonists. chlopromazine, fluephenazine,Tet and W7. The experiment results indicated that cyto- plasmic streaming was reversely inhibited only by cytochalasin B, but not by colchicine, sug- gesting that cytoplasmic streaming was control- led by microfilament. This is a typical model for studying cytoplasmic streaming. When in- tracellular Ca^(2+) was increased by introduction of 10～40 μmol/L A 23187,55～100% cells cytoplas- mic streaming stopped (Fig. 1). This evidence further confirmed that high concentration of Ca^(2+) could negatively control cytoplasmic stre- aming. Whenever 50 μmol/L CPZ or 20 μmol/L W7 was added during or after A23187 treat- ment, the reagents had no effects on the ces- sation of streaming induced by A 23187 (Fig. 2). This may imply that streaming cessation induced by high concentration of cytosol Ca^(2+) had no relation with CaM. Except W7, most of the CaM antagonists (20～100 μml/L) inhibited the normal cytoplasmic streaming considerably and reversely (Table 1, Fig. 3). CaM was detected in the culturcd cells by enzyme linked immunosorbent assay (ELISA) and was further found in cytoplasmic striation by indirect en- zyme linked immunocytochemical method (Fig. 5). These observations suggest that normal cytoplasmic streaming is regulated by Ca^(2+) and CaM.