Kaneshiro E S, Reuter S F, Quattrone F J, Morris R E
Department of Biological Sciences, University of Cincinnati, Ohio 45221.
J Protozool. 1992 Nov-Dec;39(6):713-8. doi: 10.1111/j.1550-7408.1992.tb04453.x.
It is believed that the uptake mechanism of some nutrients by Paramecium tetraurelia primarily involves transport through the cell surface, whereas the uptake of other compounds appears to be restricted to bulk transport during food vacuole (phagosome) formation. In this study, we established that, in axenically grown cells, food vacuole formation occurred at continuous rates over long periods. This information allows quantitation of the volume of media taken up by bulk transport. India ink and latex beads were shown to be inert food vacuole markers and carmine was found to have an initial stimulatory effect on phagosome formation rates. Cultures grown for 3.5 h or longer with the glycocalyx stain Alcian Blue, contained only three phagosomes/cell, whereas cells cultured with the other markers contained 15 phagosomes/cell. Electron microscopy of fecal material that accumulated at the bottom of Alcian Blue-grown cells demonstrated the presence of membranes, suggesting that the vacuolar membrane was eliminated during defecation. Neither cell lysis nor the formation of autophagous vacuoles was detected in Alcian Blue-grown cells, indicating that the stain was not cytotoxic at the concentrations used. Thus it appeared that the binding of Alcian Blue to the digestive vacuole membrane resulted in a loss of the vacuole membranes from the cell which reduced the amount of membranes retrieved and recycled and hence eventually reduced the rate of phagosome formation. Alcian Blue-treated cultures exhibited decreased rate of growth and final density, which is consistent with a decrease in bulk transport of nutrients resulting from reduced membranes of digestive cycle organelles available in the cell.
据信，四膜虫摄取某些营养物质的机制主要涉及通过细胞表面进行运输，而其他化合物的摄取似乎仅限于食物泡（吞噬体）形成过程中的批量运输。在本研究中，我们确定，在无菌培养的细胞中，食物泡的形成在很长一段时间内以持续的速率发生。这一信息使得对通过批量运输摄取的培养基体积进行定量成为可能。印度墨汁和乳胶珠被证明是惰性的食物泡标记物，并且发现洋红对吞噬体形成速率有初始刺激作用。用糖萼染色剂阿尔辛蓝培养3.5小时或更长时间的培养物中，每个细胞仅含有三个吞噬体，而用其他标记物培养的细胞中每个细胞含有15个吞噬体。对在阿尔辛蓝培养的细胞底部积累的粪便物质进行电子显微镜观察，发现了膜的存在，这表明液泡膜在排便过程中被清除。在阿尔辛蓝培养的细胞中未检测到细胞裂解或自噬泡的形成，这表明在所使用的浓度下该染色剂没有细胞毒性。因此，似乎阿尔辛蓝与消化液泡膜的结合导致细胞中液泡膜的丢失，这减少了回收和再循环的膜的数量，从而最终降低了吞噬体形成的速率。用阿尔辛蓝处理的培养物表现出生长速率和最终密度降低，这与细胞中可用于消化循环细胞器的膜减少导致营养物质的批量运输减少一致。
