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Bovine brain tubulin, purified by phosphocellulose chromatography (PC), was assembled in the presence of 10% dimethyl sulfoxide (DMSO), and the reaction was monitored turbidimetrically. Samples were fixed in glutaraldehyde-tannic acid after completion of polymerization, as indicated by no further change in absorbance, and then sectioned and studied electron(More)
Axonal extensions of neurons show microtubules (MTs) with a uniform polarity indicating that they originate at or near the perikaryon. To obtain information on the polarity of dendritic MTs, a polarity assay was used to examine MTs in dendrites of interneurons (mitral cells) of the olfactory pathway of the bullfrog. The assay involved incubating pieces of(More)
Pieces of olfactory nerve of the bullfrog were extracted in a tubulin assembly buffer medium containing detergents. With incubation at 37 degrees C in such medium containing soluble tubulin, ribbons of protofilaments are formed on the surfaces of microtubules, with the ribbons curving in a clockwise or counterclockwise direction. The direction of hooking(More)
The ultrastructure of the accessory olfactory bulb (AOB) of the bullfrog tadpole and adult was examined, and the main difference between tadpole and adult is that the latter is more compact and shows more synapses. Except for vomeronasal (VMN) glomeruli, the AOB is not highly organized, with mitral cell neurons scattered throughout the neuropil. VMN axon(More)
The substructure and distribution of luminal material in microtubules of olfactory axons were studied in the bullfrog, Rana catesbeiana. By using numerous fixation methods, with and without osmium tetroxide, the luminal component was shown not to be an artifact of fixation. The material consists of globular elements 4-5 nm in diameter loosely arranged(More)
The ciliated dendritic bulb of the olfactory neuron of the bullfrog was studied with the electron microscope, with emphasis on microtubular elements. Methods used included various fixation procedures with and without detergent extraction, serial sectioning, microtubule polarity assays, and an assay to demonstrate F-actin. Structural continuity exists, via(More)
The distribution of primary olfactory and vomeronasal (VMN) glomeruli is demonstrated in the forebrain of the larval (stage III tadpole) and adult bullfrog. Olfactory glomeruli are massed at the anterior end of the olfactory bulb; farther posterior, they are located at the periphery and then become distributed in a superficial layer all along the ventral(More)
In the present study, the structural and functional role of smooth endoplasmic reticulum was investigated in bullfrog olfactory axon terminals. Structural evidence obtained from this study indicated that this vesiculotubular organelle becomes a more elaborate network of anastomosing tubules near the nerve terminal, located in the olfactory lobe of frog(More)
Subunit structure in the walls of sectioned microtubules was first noted by Ledbetter and Porter (6), who clearly showed that certain microtubules of plant meristematic cells have 13 wall protofilaments when seen in cross section. Earlier, protofilaments of microtubular elements had been described in negatively stained material, although exact counts of(More)