PROTEIN UPTAKE AND DIGESTION IN BLOOD-STREAM AND CULTURE FORMS OF TRYPANOSOMA-BRUCEI
PROTEIN UPTAKE AND DIGESTION IN BLOOD-STREAM AND CULTURE FORMS OF TRYPANOSOMA-BRUCEI
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DOI：
10.1111/j.1550-7408.1975.tb00943.x
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发表时间：
1975-01-01
期刊：
影响因子：
--
通讯作者：
BALBER, AE
中科院分区：
文献类型：
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作者：
LANGRETH, SG;BALBER, AE
布氏锥虫在血液和培养物中对铁蛋白的摄取和消化机制不同，铁蛋白通过胞饮作用从鞭毛袋进入血液，形成大的多刺囊泡。这些囊泡变得连续，具有复杂的、大部分为管状的收集膜系统的直管延伸，其中铁蛋白被浓缩。示踪剂从收集膜系统进入大的消化泡。小的多刺囊泡，从不含有铁蛋白，在高尔基体区域发现，与收集膜系统融合，并围绕鞭毛口袋。酸性磷酸酶活性存在于一些小的多刺囊泡中，这些囊泡可能代表初级溶酶体。这种酶活性也存在于鞭毛袋、胞饮小泡、收集膜系统、高尔基体（成熟面）和血流形式的消化泡中。血液中大约50%的酸性磷酸酶活性是潜伏的。其余的非潜伏活性与细胞紧密相关，可能代表鞭毛口袋中的活性。与铁蛋白的吸收和消化有关的结构在短粗型中比在细长型血流型中更大更活跃。短粗型也有较多的自噬泡。在培养物中未观察到胞饮性大的、多刺的囊泡或高尔基体衍生的、小的多刺的囊泡。铁蛋白离开这些形式的鞭毛口袋，进入位于口袋膜凸起下方的小而光滑的池。示踪剂然后穿过池收集膜网络，在那里它被浓缩，然后进入多泡体。在培养形式中，酸性磷酸酶活性定位于池系统、多泡体、高尔基体（成熟面）以及高尔基体和池区的小泡中。鞭毛袋没有酸性磷酸酶活性，几乎所有的活性都潜伏在这些形式中。在4天的生长过程中，培养形式不会将酸性磷酸酶释放到培养基中。所有形式的铁蛋白的摄取几乎完全被低温抑制。这些细长和短粗的血流形式和培养形式之间的差异无疑是适应性的，反映了寄生虫在不同生活史阶段的不同需求。
The mechanisms of ferritin uptake and digestion differ in bloodstream and culture forms ofTrypanosoma brucei.Ferritin enters bloodstream forms from the flagellar pocket by pinocytosis in large spiny‐coated vesicles. These vesicles become continuous with straight tubular extensions of a complex, mostly tubular, collecting membrane system where ferritin is concentrated. From the collecting membrane system the tracer enters large digestive vacuoles. Small spiny‐coated vesicles, which never contain ferritin, are found in the Golgi region, fusing with the collecting membrane system, and around the flagellar pocket. Acid phosphatase activity is present in some small spiny‐coated vesicles which may represent primary lysosomes. This enzymic activity is also found in the flagellar pocket, pinocytotic vesicles, the collecting membrane system, the Golgi (mature face), and digestive vacuoles of bloodstream forms. About 50% of the acid phosphatase activity of blood forms is latent. The remaining nonlatent activity is firmly cell‐associated and probably represents activity in the flagellar pocket. The structures involved in ferritin uptake and digestion are larger and more active in the short stumpy than in the long slender bloodstream forms. The short stumpy forms also have more autophagic vacuoles. No pinocytotic large, spiny‐coated vesicles or Golgi‐derived, small spiny‐coated vesicles are seen in culture forms. Ferritin leaves the flagellar pocket of these forms and enters small smooth cisternae located just beneath bulges in the pocket membrane. The tracer then passes through a cisternal collecting membrane network, where it is concentrated, and then into multivesicular bodies. In the culture forms, acid phosphatase activity is localized in the cisternal system, multivesicular bodies, the Golgi (mature face), and small vesicles in the Golgi and cisternal regions. The flagellar pocket has no acid phosphatase activity, and almost all the activity is latent in these forms. The culture forms do not release acid phosphatase into culture medium during 4 days growth. Uptake of ferritin by all forms is almost completely inhibited by low temperature. These differences among the long slender and short stumpy bloodstream forms and culture forms are undoubtedly adaptive and reflect different needs of the parasite in different life cycle stages.