Antiviral resistance by the polyinosinic acid-poly (1-vinylcytosine) complex

The antiviral activities of analogs of the double-stranded complex of polyinosinic and polycytidylic acids [poly(I).poly(C)], which is a potent interferon inducer, have been studied. Structural changes that modify the polymer backbone substantially, such as loops or 2' --> 5' phosphodiester bonds, lead to decreased antiviral activity. Unexpectedly, however, the complex of polyinosinic acid and poly(1-vinylcytosine), which is only a much more distantly related analog of poly(I) . poly(C), shows high activity. It is postulated that the high activity is related to the reduction of the charge/mass ratio and to the existence of this complex in an aggregated state; these are two factors that generally enhance the uptake of compo unds by cells.

The photolysis of O-methylcytosine in phosphate solutions

Ultraviolet irradiation of solutions of 27 pyrimidine derivatives in the presence and absence of inorganic orthophosphate demonstrated a "phosphate effect" in only four cases. Each of these had a methyl or methoxyl group at position 2 and an amino group at position 4 of the pyrimidine ring. Ultraviolet irradiation of solutions of 4-amino-2-methoxypyrimidine containing inorganic orthophosphate gave two major photoproducts, neither of which contained a cyanide group. One was an aliphatic compound described previously, the other apparently a pyrimidine.