Tritrichomonas foetus: Fine Structure of Freeze‐Fractured Membranes¹

Abstract

Freeze-fracture techniques reveal differences in fine structure between the anterior three flagella of Tritrichomonas foetus and its recurrent flagellum. The anterior flagella have rosettes of 9-12 intramembranous particles on both the P and E faces. The recurrent flagellum lacks rosettes but has ribbon-like arrays of particles along the length of the flagellum, which may be involved in the flagellum's attachment to the cell body. This flagellum is attached to the membrane of the cell body along a distinct groove that contains few discernible particles. Some large intramembranous particles are visible on the P face of the cell body membrane at the point where the flagellum emerges from the cell body. The randomly distributed particles on the P and E faces of the plasma membrane have a particle density of 919/micron2 and 468/micron2 respectively, and there are areas on both faces that are devoid of particles. Freeze-fracture techniques also reveal numerous fenestrations in the membrane of the Golgi complex and about 24 pores per micron2 in the nuclear membrane.

Trophozoites ofGiardia lambliamay have a Golgi-like structure

“…3a,b). In favorable fracture planes, connections between the cisternae, resembling those reported in the Golgi of T. foetus [11], were observed.…”

“…Even the endomembrane system formed by the ER and the Golgi varies significantly among these cells. For instance, a highly developed Golgi is seen in Trichomonas [11,12] while a typical Golgi is not observed in Entamoeba and Giardia trophozoites [13–15].…”

Trophozoites of Giardia lamblia may have a Golgi-like structure

“…Even the endomembrane system formed by the ER and the Golgi varies signi¢cantly among these cells. For instance, a highly developed Golgi is seen in Trichomonas [11,12] while a typical Golgi is not observed in Entamoeba and Giardia trophozoites [13^15].…”

Biochemical characterization of the Golgi-complex proteins of Tritrichomonas foetus

“…In relation to pathogenic protozoa there is little biochemical information about the Golgi complex, although in some protozoa, such as Tritrichomonas foetus it is a large structure, as has been shown in several morphology studies (Honigberg et al 1971;Benchimol et al 1982). However, nothing is known about the resident-protein composition of this organelle in pathogenic protozoa.…”