Abstract
The most distinct difference between the nucleopolyhedrosis virus of Euproctis similis and those of others (NPV) was the number of nucleocapsids enveloped in an envelope. A nucleocapsid bundle of NPV in E. similis was composed of 1 to 39 nucleocapsids, and the highest frequency in the enveloped number of nucleocapsids was 7. However, small peaks apparently appeared at the number of 1, 4, 10, 12, 16, 19, 21 and 24 nucleocapsids. The arrangement of nucleocapsids in an orderly hexagonal outline were observed in cross sections of the multiply enveloped nucleocapsids and the batches of naked nucleocapsids. The rod-shaped nucleocapsid is about 40nm in diameter, 350nm in length. The triangular or irregularly distorted polyhedra are 1 to 3μ in size, and the two-combined polyhedra was rarely observed in the nucleus.
Membrane-like profiles, which have been reported only in NPV-infected Trichoplusia ni, were seen in the host cells associated with the fibrillar material structure. During the maturation process of the NPV, many virus particles were observed to be closely apposed to the clumps of fibrillar structure. However, no virus was ever seen within the fibrillar structure. Multiplication of NPV of E. similis was observed in the cytoplasm of infected fat body cell, similar to intranuclear multiplication.
