Infectious pancreatic necrosis virus (IPNV) attaches to CHSE-214 cells through two types of cell components: specific and non-specific ones. Competition experiments with inactivated IPNV showed that IPNV requires specific components to productively infect cells. Just a low amount of adsorbed IPNV enters the cell. After 20 minutes, part of the adsorbed IPNV was internalized into acid compartments. Also, the viruses adsorbed on the cell surface require similar periods of time to escape from the neutralization of antibodies.

Nucleic acid and protein electrophoretic analyses of the Chilean isolate of infectious pancreatic necrosis virus showed that genomic RNA, as well as the major proteins, were indistinguishable from those of the VR-299 serotype. The data are in good agreement with the theory that the virus was introduced into Chile from North America.

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The multiplication of IPNV in CHSE cells is inhibited by ammonium chloride. This inhibition is complete if NH4Cl is added early in the infective cycle. Immunofluorescence analysis shows that NH4Cl reduces the number of virus producing cells and thus suggests it may act by inhibiting virus internalization. In addition, NH4Cl can produce partial inhibition of IPNV multiplication if added later in the replicative cycle. Analysis of 3H-uridine incorporation into viral RNA shows that this later effect could be an inhibition of viral RNA synthesis.

Protoplasts were prepared from exponentially growing yeast cells with a lytic preparation of Streptomyces WL‐6. The following yeast strains were studied: Saccharomyces chevalieri, Candida albicans, Schizosaccharomyces pombe and Sacch. cerevisiae. True protoplasts were obtained in 100% yield after 15 min. incubation with the lytic preparation from Sacch. chevalieri and after 90 min. from Sacch. cerevisiae. For Schizosacch. pombe 10% of the cells were converted into protoplasts in the best conditions. Only spheroplasts were obtained from C. albicans.