Chapter 5 



WE 

 TRICHOmUdS 



The trichomonads belong to the family 

 Trichomonadidae within the order Trich- 

 omonadorida. The body is usually piriform, 

 with a rounded anterior end and a pointed 

 posterior end. There is a single nucleus 

 in the anterior part of the body. Anterior 

 to the nucleus is a blepharuplasl composed 

 of several basal granules . Two to five 

 anterior flagella and a posterior flagellum 

 arise from the blepharoplast. The posterior 

 flagellum passes along the border of an iin- 

 dHlati)ig me»ibrane which extends along the 

 side of the body; a secondary or accessory 

 filament may be associated with it. The 

 posterior flagellum may or may not extend 

 beyond the undulating membrane as a free 

 flagellum. A filamentous costa arises from 

 the blepharoplast and runs along the base of 

 the undulating membrane. A parabasal 

 body arises from the blepharoplast; there 

 may or may not be a parabasal filament 

 at its posterior end. A clear, rod-like 

 axostyle also arises from the blepharoplast 

 and passes thru the center of the body to 

 emerge from the posterior end. The an- 

 terior end of the axostyle is enlarged to 

 form a capitulum. There may or may not 

 be a chromatic ring at the point of emer- 

 gence of the axostyle. There may or may 

 not be a cytostome near the anterior end. 

 Just anterior to the blepharoplast and lying 

 along the anterior margin of the body is a 

 pelta which stains with silver. In addition 

 to these structures, there may be various 

 granules within or along the axostyle, 

 along the costa, or in other locations. 



An electron micrograph study of 

 Tritrichomonas muris by Anderson (1955) 

 revealed the fine structures of these or- 

 ganelles which may be taken to represent 

 the group. He found that the blepharoplast 

 appears to be limited by a membrane and 

 to contain basal granules for each organelle. 

 The anterior and posterior flagella are 

 composed of 2 central and 9 peripheral 

 fibrils. The accessory filament is com- 

 posed of two differentiated meshwork 

 areas. The undulating membrane is com- 

 posed of a series of lamellae 300 to 400 A 

 thick; it is attached to the outer surface of 

 the body by fine fibers 167 to 300 A thick. 



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