【摘要】 本文利用电镜对贻贝棘尾虫 (Stylonychiamytilus)体内酸性磷酸酶的定位进行了观察。发现其体内除含有溶酶体性的酸性磷酸酶 (ACPase)外 ,在纤毛内部还存在非溶酶体性的ACPase。另外 ,本文还利用光镜和酶细胞化学技术观察并比较了棘尾虫年轻态和衰老态个体体内ACPase在食物诱导下的表达量随时间发生的动态变化和差异 ,印证了棘尾虫个体的衰老也是与细胞内的酶的活性和含量的降低相伴随的更多还原

【Abstract】 Acid phosphatase (ACPase) is a phosphomonoesterase, that is widely dis tributed in nature, mainly localized on lysosomes, Golgi complexes, and the endo plasmic reticulum. We did two experiments on acid phosphatase (ACPase) in young and ageing cells of Stylonychia mytilus. Ageing cells came from an emicronuc leat ed clone which was obtained in Sep. 1988 and had undergone more than 2000 asexua l cell divisions up to the present experiment. Young cells came from a new clone which originated recently from an exconjugant and had passed through only about 100 cell divisions. The two experiments were:Ⅰ. Observe the localization of ACPase in the young cells with enzyme cytochemical techniques and electron micro scopy. After being fed for 30 min, young cells were fixed with glutaraldehyde ( 2 5%) and paraformaldehyde (4%) in sodium cacodylate buffer and incubated in in cubating liquid (6 ml distilled water +2 ml tris maleicacid +2 ml lead nitr ate +2 5 mg β sodium phosphoglycerol) at 37 ℃ for 2 5-3 hr, re fixed for 10 mi n in 2 per cen t osmium tetroxide, gradient dehydrated in acetone, embeded in EPON812 and secti oned with a Leica ultramicrotome. Sections were viewed with a JEOL 1200 transmi s sion electron microscope. In the control experiment redistilled water replaced phosphoglycerol in the incubating liquid. Electron microscopy revealed that ther e are three positive ACPase reaction sites in Stylonychia mytilus : (1) in th e cilia; (2) on the lithosomes (Hausmann et al .,1996) and tubular bodie s i ns ide the digestive channels (Kaul et al .,1982); (3) in the food organisms. The ACPas e on the tubular bodies and in the food organisims inside digestive channels is lysosomic ACPase. This has been described by Kaul et al . (1982), who suggest ed t hat this was involved in the digestive process of Stylonychia . Lithosomes ar e sp herical deposits produced from concentric layers of organic and inorganic materi al inside the digestive channels. Hausmann considered it to be organic crystal. ACPase on lithosomes function in autophage and autolysis. Our discovery of ACPa se in the cilia of Stylonychia mytilus has not previously been reported. Thi s sh ould be a polysomic enzyme. However, its function remains unknown. Ⅱ. To trace the expression quantity of ACPase in Stylonychia mytilus and to compare diff eren t expression quantities between young and ageing cells during different digestiv e periods. The dynamic expression process of ACPase was observed using cytochemi cal and light microscopic techniques. We fed all cells to induce ACPase expressi on, then fixed the two groups of cells at different times. The time at which cel ls were fixed was selected as follows: before feeding fixed once only, during fe eding fixed once every 5 min over a 0-30 min interval and once every 30 min ove r a 0 5-5 hr interval. After food had been removed cells were fixed once every 30 min. Fixed cells were incubated in incubating liquid made of 6 ml distilled water +2 ml tris maleicacid +2 ml lead nitrate +2 5 mg β sodium phosphoglyce rol for 1-1 5 hr (25 ℃), stained in ammonium sulfide for 3-5 min, mounted on sl ides with a protein adhesive, hierarchically dehydrated in alcohol, cleared with xyle ne, mounted in balsam and observed with light microscopy. In the control experim ent redistilled water replaced β sodium phosphoglycerol in the incubating solu t ion. The expression process included four phases, i.e. primary phase, high peak phase, wind down phase and termination phase. The primary phase appeared after a bout 10 min of feeding in both young and ageing cells. ACPase is an epigamic enz yme and its expression is food induced. This can explain why theres no ACPase expression in cells before and during the first 10 min of feeding. The high peak phase and termination phase in ageing cells appeared much later than in young c ells, in which the high peak phase appeared about 1 5 hr earlier than in ageing cells. The entire digestive process of young cells required about 12 hrs compare d to 18 hrs更多还原