Immunochemical characterization of Lymantri dispar NPV hemagglutinin: protein-carbohydrate interaction.

The agglutination of chicken erythrocytes by Lymantria dispar nuclear polyhedrosis virus polyhedrin has been shown to provide specific virus identification. Selected mono- and oligosaccharides, present in blood group substances, were assayed by the Land-steiner hapten inhibition technique for specific inhibition of polyhedrin hemagglutination. N-acetylgalactosamine and N-acetylglucosamine inhibit to the greatest extent; galactosamine, glucosamine and fucose to a lesser extent. The hapten inhibition data suggest that a monosaccharide possessing an equatorial 2-acetamido group interacts most avidly with the polyhedrin-combining site. Bergold demonstrated that the polyhedrin dissociates into six subunits at a pH greater than 10.0. Diafiltration equilibrium and Scatchard analysis indicate that N-acetylgalactosamine binds most avidly to the polyhedrin (Kd = 1.7 X 10(-6)) which contains six available sites, suggesting that one hemagglutination site resides on each subunit. Since virions derived in vivo and polyhedrin are serologically cross-reactive, this protein-carbohydrate interaction may play a role in host infectivity by providing a receptor site for virus attachment to target cells.     

Histochemistry and acetylcholine receptor distribution in normal and denervated monkey extraocular muscles.

In monkey extraocular muscles (EOM), a battery of histochemical reactions delineates three muscle fiber types, coarse, fine, and granular. Normal EOM are compared with EOM denervated by intracranial oculomotor nerve section. The experimentally denervated EOM fibers did not show the constellation of histologic responses typical of denervated limb muscle, making a diagnosis of a denervation process in EOM muscle very difficult. Although the denervated fine and granular fibers (but not the coarse fibers) develop diffuse extrajunctional acetylcholine receptors (AChR) following experimental denervation, this is not a reliable criterion of denervation because not all of those fibers developed it and they did not show it beyond a 12-week period following nerve section; moreover, myopathic mechanisms have previously been shown capable of provoking diffuse extrajunctional AChR in limb-muscle fibers.     

Absorption of Vitamin B12 in the Guinea-Pig III. THE FORMS OF VITAMIN B12 IN ILEAL MUCOSA AND PORTAL PLASMA IN THE FASTING STATE AND DURING ABSORPTION OF CYANOCOBALAMIN

S ummary . The forms of vitamin B₁₂ in guinea-pig ileum, liver and portal plasma were studied using a chromatographic-bioautographic technique. 5'Deoxyadeno-sylcobalamin was the principal cobalamin in each tissue although significant amounts of methylcobalamin were detected in plasma. An unidentified cobalamin was also found in all three tissues.
During the absorption of labelled cyanocobalamin a proportion of this analogue was converted to 5'deoxyadenosylcobalamin in the ileum; preliminary experiments suggest that the site of inter-conversion was the mitochondria of the ileal epithelial cells. A significant proportion of the cyanocobalamin was transferred to the portal plasma unchanged however, indicating that the mitochondrial localization of vitamin B₁₂ during its absorption, shown in previous studies, is not solely related to the conversion of vitamin B₁₂ analogues from one form to another.