Physico-chemical and Morphological Features of Infectious Pancreatic Necrosis Virus

Abstract

SUMMARY Infectious pancreatic necrosis (IPN) virus has been purified and some physico- chemical properties of its nucleic acid and protein moieties have been determined. The buoyant density of the virus particle in CsC1 is 1.35 g/ml; degraded particle banded at a density of 1.31 g/ml. The virus nucleic acid was found to be double- stranded, according to several different criteria, namely resistance to pancreatic RNase, low density in Cs2SO4 (I'615), sharp melting curve with a T~ of 89 °C in hypotonic buffer, and base composition. In a sucrose gradient the bulk of the virus RNA banded as a single peak (i 4 S); a small part of the virus nucleic acid was found at the top of the gradient. By gel electrophoresis virus RNA was resolved into three peaks corresponding to double-stranded molecules with mol. wt. ranging from 2"8 5 × I06 to 2"55 × I06. Gel analysis of virus proteins revealed three polypeptides of tool. wt. 8o, 5o and 3o × IO ~, representing respec- tively 3 ~, 68 9/00 and 29 ~oo of the total protein. On the basis of these results IPN virus appears to be related to some reo-like viruses, having a single protein shell and a single class of double-stranded RNA.