Effect of parainfluenza-3 virus neuraminidase on the structure of the gel phase of bovine nasal secretion.

The gel phase of bovine nasal secretion was separated from the liquid phase and exposed to parainfluenza-3 virus or Vibrio cholerae neuraminidase under optimal in vitro conditions. N-Acetylneuraminic acid was released from the gel by either neuraminidase. The release of N-acetylneuraminic acid was accompanied by a decrease in the net negative charge of the gel, as evidenced by free zone electrophoresis. Scanning electron microscopy showed that after exposure to neuraminidases the regular network structure of the untreated gel attained a coarse, irregular structure. Samples of gel incubated with 0.15 M sodium chloride under similar conditions did not show changes in the net charge or morphology.