Intercisternal Material in the Golgi Body of Trichomonas

In the flagellate Trichomonas, the Golgi apparatus is present in the form of an organelle which has long been called the parabasal body. This term was applied before it was recognized that the structure is a Golgi system. The parabasal body is a long, cylindrical organelle, about 1 pu in diameter and, in one species (T. gigantea), up to 200 y long. It has the typical fine structure of a Golgi body, consisting of a stack of flattened, longitudinally oriented cisternae, together with associated vesicles. It differs from most other Golgi bodies in that a fiber, the parabasal filament (Figs. 4, 6), runs along the whole length of the organelle and terminates on one of the flagellar basal bodies situated at the anterior end of the cell. Such a filament is present in the Golgi bodies of some other flagellates, and in Trichonympha it has been shown that this filament lies on the concave, proximal face of the organelle, where new cisternae are believed to be formed (Grimstone, 1959). The opposite, distal face of the parabasal body is thought to be the site of vacuole formation. This paper is chiefly concerned with the parabasal bodies of some large members of the genus Trichomonas which live as symbionts in the gut of termites. In these forms, as in other flagellates, the parabasal body is readily seen in the light microscope after staining by Bodian's silverproteinate method. Kirby (1944), studying 7'. termopsidis, noted that in such preparations the organelle has a nodose appearance, consisting of alternating light and dark regions (Fig. I). It is difficult to observe the parabasal body in life in T. termopsidis, but it can be seen quite readily in an as yet undescribed species from the termite Porotermes adamsoni, and here the nodose structure is again apparent (Fig. 2). The finestructural basis of this nodose appearance has recently been determined in T. termopsidis and T. gigantea and appears to merit brief description, since this appearance results from a type of differentiation seemingly unlike that found in other Golgi bodies. T. termopsidis used in this study was obtained from the termite Zootermopsis angusticollis, and T. gigantea from Porotermes adamsoni. No essential difference has been detected between the parabasal bodies of these two species. The flagellates were fixed in cacodylate-buffered 2.5% glutaraldehyde, postfixed in buffered 1% osmium tetroxide, dehydrated in ethanol, embedded in Araldite epoxy resin, and sectioned in the usual way. Some material was fixed in osmium tetroxide alone. Sections were stained with both uranyl acetate and lead citrate. Fig. 3 shows an approximately longitudinal section of a small part of a parabasal body in