[Detection of virus-specific protein synthesis in animal organs]. / Vyiavlenie virusspetsificheskikh belkovykh sintezov v organakh zhivotnykh.

Registration of intracellular protein syntheses in vivo was shown to be possible by inoculation of labeled amino acids directly into animal organs. In the lungs of intranasally infected mice there occurs inhibition of cellular protein syntheses against the background of which synthesis of virion proteins is recorded. In the brains of intracerebrally inoculated animals intracellular protein synthesis is enhanced. The recommended approach opens ways for investigations of the molecular mechanisms of the pathogenesis of viral infections as well as mechanisms of virulence.

[Effect of protease inhibitors on influenza virus reproduction]. / Vliianie ingibitorov proteaz na reproduktsiiu virusa grippa.

Natural inhibitors of proteases have been shown to inhibit plaque production by influenza virus. Investigation of the fate of viral intracellular proteins revealed the inhibiting effect of these inhibitors on their posttranslation cutting. It is assumed, therefore, that the antiviral effect of the preparation under study is associated with inhibition of viral proteins cutting, in particular, of hemagglutinin. A comparative study of the antiviral activity of inhibitors of proteases from various sources was carried out: from potato, haricot, common honey locust, as well as trypsin inhibitor from soybeans. The highest antiviral activity determined by the plaque reduction test was found with the preparation obtained from potato.

[Synthesis of influenza virus protein in the inhibition of cellular DNA transcription]. / Sintez belkov virusa grippa pri podavlenii transkriptsii kletochnoi DNK.

After preliminary UV-irradiation of cells as well as in the presence of actinomycin D the doses of both agents inhibiting influenza virus production are slightly lower than those inhibiting formation of viral proteins and considerably lower than those producing complete blocking of viral genome expression. These data demonstrate the existence of a cellular DNA-dependent factor the blocking of which prevents the formation of virus progeny without preventing primary transcription and formation of virion proteins. It is assumed that, apart from relatively small genes of cellular DNA participating in primary transcription of viral genome, some larger genes of the cell take part in some process of influenza virus reproduction.

Gradual changes of influenza virions during passage of undiluted material.

Defective influenza virions undergo gradual changes during passage of undiluted material: the amount of RNA in virions diminishes, the equimolarity of the RNA segments is lost and the interfering activity of defective virions decreases. Defective virions of early passages have a small deficiency in genetic material and at a high m.o.i. induce the synthesis of the complete set of virus-specific proteins. Defective virions from later passages are characterized by a considerable deficiency in genetic material and a decrease in the amount of high mol. wt. RNA segments. They do not demonstrate complementation and at a high m.o.i. do not induce the synthesis of virus-specific proteins, thus revealing analogous defects in the genome of the majority of defective virions. The characteristics of protein synthesis in cells infected with these virions are similar to those in uninfected cells. During undiluted passage of influenza virus the cyclic production of defective and infectious virions takes place.

[Interrelationships between the interfering capacity of an "incomplete" virus and its infectivity]. / Vzaimootnosheniia mezhdu interferiruiushchei sposobnost'iu "nepolnogo" virusa grippa i infektsionnost'iu.

A comparative analysis of UV inactivation curves of the interfering activity of "incomplete" influenza virus and infectivity showed certain differences in the structures responsible for these functions. All the data exclude the role of virus protein and virus-induced interferon of "incomplete" influenza virus and suggest that RNA is responsible for this interference. The size of the "target" of the "incomplete" virus interfering capacity calculated on the basis of sensitivity to UV-light is approximately 40 times as small as that of the "target" responsible for infectivity. The analogous pattern of UV inactivation in the standard influenza virus and the so-called Magnus virus suggests that in the latter the infectivity is due to the presence of complete virions in the preparation.

[Analysis of the nature of virus-associated DNA in the influenza virus]. / Analiz prirody virusassotsiirovannoi DNK u virusa grippa.

DNA sequences comprising about 5% of virus RNA were found to be present in nucleoids of influenza virus grown in chick embryos. DNA was found in two influenza virus strains under study belonging to different antigenic groups: HONI and H3N2. No DNA was demonstrated in nucleoids of a paramyxovirus, Newcastle disease virus, grown under analogous conditions. The virus-associated DNA belongs to unique sequences of cell DNA.

[Use of the plaque method to reveal the phenomenon of autointerference in influenza virus]. / Ispol'zovanie metoda bliashek dlia vyiavleniia fenomena autointerferentsii u virusa grippa.

The paper describes a simple and convenient method for qualitative and quantitative evaluation of the capacity of influenza virus for autointerference consisting in the lack or considerable reduction of the cytolytic effect of the virus under agar overlay at a high multiplicity of infection. Some experimental and theoretical arguments assuming the role of defective interfering particles in the formation of the observed phenomenon. It is assumed that the detection of autointerference under agar may be used as an additional criterion for detection of non-plaque-forming strains of influenza virus, tentative determination of their interfering capacity as well as for the establishment of biological relationships of viruses.

DNA sequences in influenza virions.

During the propagation of A (H3N2) influenza virus in chick embryos, incorporation of 3H-thymidine into virions takes place, whereas no such incorporation occurs with Newcastle disease virus. Incorporation of 3H-thymidine is a result of DNA synthesis. This virion-associated DNA is present in cores obtained after treatment of virions with bromelain.

[Detection of DNA in the composition of influenza virus]. / Vyisvlenie DNK v sostave virusa grippa.

When influenza virus multiplies in chick embryos, incorporation of 3H-thymidine into virus particles is observed. The radioactivity is localized in influenza virus nucleoprotein. The analysis of 3H-thymidine-containing structures in cesium chloride density gradient permits to qualify them as DNA. Isodensity centrifugation of in vitro 125I-labeled preparation of nucleic acid from influenza virus in cesium sulphate gradient also reveals DNA molecules, in addition to RNA. A high hybridization rate of influenza virus 125I-DNA with virion RNA has been demonstrated.