A. Rambourg

Tri-dimensional structure of the forming face of the Golgi apparatus as seen in the high voltage electron microscope after osmium impregnation of the small nerve cells in the semilunar ganglion of the trigeminal nerve

When rat trigeminal ganglia were osmicated for 45 h at 40°C in a 1% unbuffered aqueous solution of osmium tetroxide, only the one saccule located on the forming face of the Golgi stacks was impregnated with osmium. This staining property was therefore utilized to examine with the high voltage electron microscope the tri‐dimensional structure of the forming face of the Golgi apparatus of the small nerve cells using sections whose thickness ranged from 1 to 7 μm.

Tridimensional analysis of the formation of secretory vesicles in the Golgi apparatus of absorptive columnar cells of the mouse colon

The tridimensional structure of the Golgi apparatus has been studied in the absorptive cells of the mouse colon by means of reduced osmium postfixation and phosphatase cytochemistry. In thick sections of tissue impregnated with osmium tetroxide or treated with a technique to demonstrate TPPase activity, the Golgi formed a continuous ribbon‐like structure capping the upper pole of the nucleus. Along the longitudinal axis of this ribbon, compact zones made up of super‐posed flattened saccules alternated with less compact zones which consisted of highly perforated saccules of bridging anastomosed tubules. In the cis‐trans axis, the following elements were observed: (1) a cis element consisting of a continuous osmiophilic tubular network; (2) two or three subjacent elements selectively perforated by wells; (3) a trans compartment made up of two or three TPPase‐reactive sacculotubular elements, some showing a “peeling‐off” configuration. In some regions, the first flattened saccule of this trans compartment displayed discrete ovoid dilatations, located in compact zones and containing a dense granulofibrillar material; in the subjacent elements this material was seen concentrated in nodular swellings, at the intersection of the meshes of anastomosed membranous tubules. 100–300 nm vesicles containing a similar dense granulofilamentous material were observed in the trans Golgi zone and interspersed in the supranuclear cytoplasm between the Golgi zone and the apical surface of the cell. Smaller vesicles 80–100 nm in diameter containing a fine dusty material were also seen in proximity. These morphological observations suggested that at least two kinds of material were segregated in the saccules of the trans compartment and packaged in vesicles of two class sizes that detached from the Golgi stack on its trans aspect.

Effects of low temperature on the formation of secretion granules in the Golgi apparatus of granular cells of the frog urinary bladder

Summry— The formation of secretion granules has been studied in the Golgi apparatus of granular epithelial cells of frog urinary bladders maintained at room temperature or cooled at 4°C for various lengths of time. In control animals, the Golgi apparatus was composed of the following stacked elements: subjacent to the cis‐rmelement mad up of anastomosed tubules, two elements in the mid‐compartment consisted of flattened saccules interconnected by tubules. On the trans‐face, two or three sacculo‐tubular elements were slightly dilated by an electron dense granular material. In the trans‐Golgi elements, this material was segregated into dilatations of various sizes and shapes which are continuous with flattened portions devoid of stained material. In the trans‐Golgi region, free irregular progranules, seemingly formed by rupture of the trans‐most Golgi elements. In granular cells examined after 4 h at 4°C, all Golgi compartments were affected by the low temperature. The cis‐half portion of the Golgi apparatus consisted mainly of anastomosed membranous tubules and the cis‐element was no longer recognizable. The trans‐compartment was reduced to a few flattened saccules with progranules hardly visible on their trans‐aspect. At later time intervals, there was a progressive reconstitution of the cis‐zone while saccular elements started to pile up in the trans‐compartment. At 24 h, the trans‐compartment comprised six to eight saccular elements which showed irregular dilatations filled with granular material separated by large flattened portions. These various observations were interpreted as indicating that the trans‐compartment was a dynamic structure undergoing continuous renewal.