The fine structure of Crithidia fasciculata with special reference to the organelles involved in the ingestion and digestion of protein

  • B. E. Brooker
Article

DOI: 10.1007/BF00335057

Cite this article as:
Brooker, B.E. Z. Zellforsch. (1971) 116: 532. doi:10.1007/BF00335057

Summary

As in other trypanosomatids, the cell membrane of Crithidia fasciculata overlies a single layer of microtubules. Each microtubule possesses a large number of periodically arranged drumstick-like appendages and adjacent microtubules are joined by fibrillar connectives. Anteriorly, the microtubules gradually taper to terminate just before or just after entering the reservoir. An attempt is made to correlate microtubule tapering with maintenance of form of the truncated anterior end of the cell. Smooth and coated vesicles are proliferated from the Golgi saccules and the prominent contractile vacuole lies nearby. The single mitochondrion is extensive and expanded at one point to form a capsule for the kinetoplast. The cristae are predominantly plate-like but other configurations do occur. The cytostome, a shallow invagination of the reservoir membrane, is found between two constrictions in the reservoir wall. Supporting the cytostome are several microtubules which penetrate deeply into the cytoplasm. Ingestion of ferritin occurs by pinocytosis from the cytostome and by coated vesicle formation from the reservoir membrane. Digestion probably occurs in multivesicular bodies which contain acid phosphatase activity.

Key-Words

Trypanosomatids Crithidia fasciculata Fine structure 

Copyright information

© Springer-Verlag 1971

Authors and Affiliations

  • B. E. Brooker
    • 1
    • 2
  1. 1.Department of ZoologyBritish Museum (Natural History)London
  2. 2.The Zoological Society of LondonNuffield Institute of Comparative MedicineLondonEngland