Cockroach muscle hemagglutinins - candidate recognition macromolecules

Endogenous lectins in normal and dystrophic muscle development

Two endogenous lectin activities, one specific for beta-D-galactose (beta-D-Gal) residues and purified on asialofetuin-Sepharose and the second specific for iduronic acid containing glycosaminoglycans and purified on heparin-Sepharose, have been studied during myogenesis in both normal and dystrophic chickens. The Storrs strain, homozygous for muscular dystrophy, and the dystrophic strain 413 from the University of California at Davis were both used in this study. Strain 412 and local hatchery chickens were used as controls. The lectins derived from all sources appeared to be identical based on physical properties and carbohydrate specificity. Both normal and dystrophic adult chickens possessed similar lectin levels in lung, spleen, kidney, heart, and muscle tissue. No differences were noted in the temporal appearance of the heparin-binding lectin; however, the beta-D-Gal-binding lectin appeared earlier in the Storrs dystrophic strain than it did in the 413, 412, or hatchery embryos.

Lectin receptors in the cockroach neuromuscular system. II. Effects of denervation on muscle lectin receptors

The binding of fluorescent derivatives of plant lectins to the 6 coxal depressor muscles in the leg of the cockroach was examined at 1, 2, 3 and 5 weeks after denervation. Histochemical analysis of the binding of the lectins to frozen sections of the muscles demonstrated that all detectable binding was to the surfaces of the muscle fibers. In addition, within one week of denervation those muscles which in the innervated state have different amounts of D-galactose and/or alpha-N-acetylgalactosamine on their surfaces, now all have identical amounts of these carbohydrates. Biochemical analysis of concanavalin A and wheat germ agglutinin glycoprotein receptors by sodium dodecylsulphate polyacrylamide gel electrophoresis indicated that approximately 17% of all the receptors detected altered their relative levels in denervated muscles. These changes were observed in those receptors that were present in equal amounts in each of the muscles as well as in those receptors that were distributed among the 6 muscles in a manner that correlated with innervation by an identified motor neuron. However, in spite of these changes that reduced the biochemical differences in the denervated CDMs it was still possible to distinguish among the 6 muscles by the nature of the Con A and WGA glycoprotein receptors. Denervated muscles still present biochemically different cell surfaces to regenerating motor neurons.

Identified motor neurons in the cockroach exhibit stereotypic peripheral branching and nerve terminal structure

The peripheral branching of the identified motor neurons Df and Ds which innervate the coxal depressor muscles in the legs of cockroaches was examined using the anterograde transport of a cobaltic-lysine complex and the retrograde transport of cobaltous ion or horseradish peroxidase. In all animals the axons of these motor neurons leave the ganglion in the dorsal portion of nerve root 5 and undergo a 180 degree spiral that brings them directly to the first branch. They leave the nerve root at this branch to innervate the muscles. The pattern of branching of Df within muscles 178 and 179 was highly stereotyped with little variability being observed among identical and homologous muscles within the same and different individuals. The great extent of the neuronal branching within the muscles suggests that a relatively large percentage of the surface area of the muscle fibers is involved in intercellular interactions with the motor neurons. The two motor neurons could also be distinguished by the structure of their axon terminals. Those of Df were beaded and extended either parallel or perpendicular to the muscle fiber. those of Ds were thinner, wavy, less regular, and appeared with a greater frequency. Identified neurons may therefore be further characterized by their stereotypical peripheral branching and axon terminal structure.