Though the fagellum of Sciara sperm arises from a blepharoplast and is characterized by doublet tubules with arms, it differs markedly from the familiar type of flagella in the number and arrangement of its tubules. The axial filament complex in sperm from the testis of Sciara consists of approximately 70 doublet tubules, each with an associated singlet tubule. Near the nucleus these tubules are displaced in an oval array. Posteriorly the oval breaks and coils from one free end so that the axial filament complex at posterior levels has the form of a spiral. The singlet tubules do not extend the full length of the sperm but terminate in order from inside the spiral. Farther posteriorly the axial filament complex reverses the direction of coiling, and the doublets terminate from outside the spiral. Four arms are specifically positioned on the singlet and doublet tubules. A single mitochondrial derivative extends most of the length of the sperm; it consists of a large mass of proteinacious material, a crystalloid located adjacent to the axial filament complex, and peripheral cristae. In the female genital tract, sperm undergo gross morphological changes which include sloughing of practically all the mitochondrial material except the crystalloid, repositioning of the crystalloid, and uncoiling and subsequent recoiling of the axial filament complex into a different configuration. From analysis of serial sections it was determined that the orientation of arms, when the axial filament is viewed from base to tip, is the same as in conventional flagella.
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Article| September 01 1966
FINE STRUCTURE OF SCIARA COPROPHILA SPERM
David M. Phillips
From the Whitman Laboratory, The University of Chicago, Illinois.
The author's present address is the Department of Anatomy, Harvard Medical School, Boston, Massachusetts
Received: February 18 1966
Online Issn: 1540-8140
Print Issn: 0021-9525
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David M. Phillips; FINE STRUCTURE OF SCIARA COPROPHILA SPERM . J Cell Biol 1 September 1966; 30 (3): 499–517. doi: https://doi.org/10.1083/jcb.30.3.499
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