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PubMedDate not supplied

[Complementary interaction of multialkylated polyribonucleotides].

Effect of modification of polyinosinic acid (poly(I)) by alkylating agent 4-N,N-bis (beta-chloroethyl) aminobenzaldedehyde on its complementary interaction with polycytidylic acid (poly(C)) was investigated. The data demonstrate that when no more than 10% of inosine residues are modified poly(I) still retains its capacity to form complementary complex with poly (C) this capacity disappears after modification of 11--13% of inosine residues. However when more than 3,5% of inosine residues were modified the poly(I). .poly(C) complex became sensitive to RNAse T1 and its Tm decreases, indicating that single-stranded regions (loops) are formed under these conditions. The data suggest that modified polynucleotides carrying alkylating groups on their surface can be applied for the directed action on the complementary regions of the genome.

Alkylation↗
PubMedDate not supplied

[Combined antiviral effect of synthetic polyribonucleotide interferonogens and specific antiviral antibodies in arbovirus infections].

A model of tick-borne encephalitis in BALB/c mice was used to investigate the protective anti-viral effect of an interferon inducer, poly(G).poly(C), and specific gamma-globulin administered to the animals together or separately in small doses 24 hours before or after virus inoculation. Administration to the animals of poly(G).poly(C) alone or gamma-globulin alone was shown to produce a poor protective effect. Simultaneous administration of both preparations resulted in a significant decrease of mouse mortality after infection. As a result of the pretreatment of chick embryo cell cultures with poly(G).poly(C) before inoculation and the addition of specific immune serum to the agar overlay after the Sindbis virus inoculation, its multiplication was inhibited much more than after treatment of the cells with interferon inducer alone or antibody alone. Possible mechanisms of the observed additive antiviral effects of the interferon inducer and antibody, including those associated with the influence on the virus-induced interferon production, as well as the possibility of their combined use for the prevention and treatment of viral infections are discussed.

Animals↗
PubMed1983

Electrochemistry of double-stranded complexes of synthetic polyribonucleotides having interferonogenic and antiviral activity.

Double-stranded (ds) complexes of poly(C) with poly(G) and poly(G,I) were studied using differential pulse polarography (DPP) and differential pulse voltammetry at a pyrolytic graphite electrode (DPV). The complex formed by copolymer was found to be DPP inactive. On the other hand, poly(G).poly(C) yielded a small DPP peak corresponding to single-stranded (ss) poly(C). It was suggested that ss poly(C) present in the solutions of poly(G).poly(C) appeared due to the existence of segments in poly(G) during the complex-forming process in which guanine residues were unable to be hydrogen-bonded with bases in poly(C). Polynucleotide complexes investigated in this report yielded a DPV peak corresponding to electrooxidation of guanine residues, which was markedly lower than that yielded by ss polymers. Moreover, this DPV peak yielded by the complex prepared from an equimolar mixture of poly(G) and poly(C) was still markedly higher than that yielded by poly(G,I).poly(C), or by poly(G).poly(C) prepared in the excess of poly(C). The lowering of the DPV peak was explained as being particularly due to the presence of the polynucleotide segments with an intact and regular secondary structure. The results of our electrochemical analysis of the complexes investigated were compared with their biological activity reported earlier. This comparison calls attention to the fact that biological effectiveness of these biopolymers may be dependent on details of their secondary structure which may be monitored using the methods of electrochemical analysis.

Antiviral Agents↗
PubMedDate not supplied

[Conformational possibilities of the regular single-stranded polyribonucleotides].

It was shown that in case of C(3')-endo pucker of ribose two left and two right types of helices are possible from the energetical point of view. However, such helices with C(2')-endo conformation of ribose are extremely unfavourable due to the steric hindrance caused by 2'-OH group. In this case the low energy structures have bases outside and phosphate groups inside the helix. The right and the left poly(A) helices have similar energy values, the barrier of transition between them being rather small. Biregular structures, i.e. the helices on which dinucleotide serves as the repeating unit, were also considered. These forms proved to be energetically optimal in the case of poly(A-C).

Models, Molecular↗
PubMed1980

Antibodies to natural double-stranded RNA and to synthetic polyribonucleotides in the sera of patients with systemic lupus erythematosus.

A parallel testing of antibodies to double-stranded ribonucleic acid in 80 sera from patients with systemic lupus erythematosus by the membrane binding method using natural 3H-dsRNA preparation and synthetic 125I-poly I. poly C preparation revealed a good correlation (r = +0.81). In a selected set of patients with SLE we observed a slight tendency to preferential binding of the natural preparation and a lower frequency of anti-dsRNA antibodies when compared to that reported by other investigators. The presence of anti-dsRNA did not correlate with the presence of anti-dsDNA.

Antibodies↗