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Biomedical subjects

I S Lukashevich

Publications and source records attributed to I S Lukashevich.

12 recordsLinked to original sources
PubMed1992

Generation of reassortants between African arenaviruses.

Lassa (LAS) and Mopeia (MOP) viruses are African arenaviruses which are carried by wild rodents and occasionally transferred to humans. In humans and nonhuman primates, Lassa causes mortality in 60% of untreated cases, whereas Mopeia does not cause mortality and has been known to protect monkeys from lethal challenge with Lassa. These two African arenaviruses also differ in their lethality for suckling outbred mice and in their plaque sizes under agar overlay. MOP virus induces small plaques and lethal infection after intracerebral (ic) inoculation. In contrast, LAS inoculation does not kill mice and the virus induces large plaques. After coinfection of Vero cells with LAS and MOP viruses some phenotypic reassortants which produced small plaques and were not lethal for outbred mice were isolated and plaque-purified. Dot-blot hybridization using LAS and MOP cDNA probes specific for L and S RNA segments revealed a genotype consisting of the L RNA of MOP and the S RNA of LAS (MOP/LAS reassortant). Adoptive transfer experiments demonstrated an ability of immune splenocytes from CBA mice intraperitoneally infected with the MOP/LAS reassortants to protect recipient mice against lethal disease after ic inoculation with LAS virus.

Animals↗
PubMed1990

Lassa virus glycoproteins: antigenic and immunogenic properties of synthetic peptides to GP1.

Synthetic peptides corresponding to predicted Lassa virus GP1 glycoprotein B-epitopes were used to study the antigenicity and immunogenicity of the protein. ELISA results showed that guinea pig polyclonal anti-Lassa virus serum bound effectively to peptides corresponding to amino acid residues 119-133 and 164-176 of the GP1 protein. Essentially it did not react to a peptide corresponding to GP1 amino acid residues 234-256. Sera obtained against peptides representing amino acid residues 119-133 and 164-176 reacted with inactivated purified Lassa virus.

Amino Acid Sequence↗
PubMed1979

Newcastle disease virus-specific RNA: an analysis of 24 S and 35 S RNA transcripts.

The denaturation of Newcastle disease virus-specific 24 S and 35 S RNA by heat or formamide treatment led to a shift of a large part (60--80%) of RNA into the 18 S zone. The remaining 20--40% could not be dissociated further by repeated denaturation or by centrifugation in dimethyl sulfoxide-sucrose gradient. Hybridization-competition analysis revealed that the majority (approximately 75%) of the non-dissociable 35 S RNA and almost all the material present in the non-dissociable 24 S RNA were represented by nucleotide sequences homologous to 18 S RNA. On the other hand, the non-dissociable 35 S RNA lacked some of the sequences present in 18 S RNA, since no more than 45% of the labelled 18 S RNA could be displaced from the hybrid by an excess of unlabelled non-dissociable 35 S RNA. The possible origin of 24 S and 35 S RNA is discussed.

Base Sequence↗
PubMed1976

Newcastle disease virus-specific RNA: poly(A)-containing and poly(A)-deficient transcripts as revealed by chromatography on poly(U)-sepharose.

Total [3H]uridine-labeled, virus-specific RNA from Newcastle disease virus-infected cells was fractionated by poly(U)-sepharose chromatography and analyzed by rate zonal gradient centrifugation. The sedimentation pattern of both eluted and nonadsorbed RNA resembled that of the total RNA. However, nonadsorbed RNA was enriched in 50S material, ant its 18S peak was broader and slightly shifted towards the top of the gradient. Poly(U-sepharose chromatography of isolated 18S RNA and 24S RNA resulted in the separation of poly(A)-containing RNA and poly(A)-deficient RNA. In the former the percentage of adenosine content represented by poly(A) sequences was estimated as 10 to 12% (for 18S RNA) or approximately 6.0% (for 24S RNA). The size of poly(A) fragments as measured by their sedimentation rate was the same for 18S and 24S RNA. Polyacrylamide gel electrophoresis of poly(A)-containing RNA revealed a characteristic pattern closely resembling the pattern of nonchromatographed 18S and 24S RNA. The pattern of poly(A)-deficient RNA was heterogenous, and for 18S RNA it shifted towards the anode. The possible origin of poly(A)-deficient transcripts is discussed.

Base Sequence↗
PubMedDate not supplied

[Utilization of poly U-cellulose and poly U-sepharose for the study of virus-specific RNA of Newcastle disease virus].

Comparative characteristics of poly(U)-cellulose and poly(U)-sepharose used for the study of virus-specific 18S RNA of Newcastle disease virus are presented. Upon chromatography of 18S NDV RNA on any of these columns, approximately 60-70% RNA was adsorbed. The sorbing RNA contained in poly(A) 10-12% of the total amount of adenosine, in contrast to RNA not adsorbed on the column in which poly(A) contained 1-2% of the total amount of adenosine in RNA molecule. The analysis in sucrose density gradient and polyacryl amide gel of the RNAs eluated from the columns showed RNA chromatography under the conditions used not to cause its degradation. The advantages and short-comings of the sorbents used in studies of virus-specific RNA are discussed.

Cellulose↗
PubMedDate not supplied

[Sedimentation properties of virion RNA of Newcastle disease virus after annealing under different conditions].

After annealing at high temperatures 50S RNA of Newcastle disease virus was partially degraded. The resulting fragments had the sedimentation coefficient of 23--32S. Solution of dimethylsulfoxide and formamide were used to decrease the temperature of annealing. However, annealing with denaturating agents caused agglomeration of 50S RNA molecules. This phenomenon is discussed.

Centrifugation, Density Gradient↗
PubMedDate not supplied

[The detection of the Marburg virus antigen by solid-phase immunoenzyme analysis].

Comparative studies of two variants of the enzyme-linked immunosorbent assay (ELISA) were carried out to determine the sensitivity of the detection of Marburg virus antigens in Vero cells. Both competitive and two-antibody ELISA variants detected as little as 5 ng of Marburg virus antigen. The Vero cell monolayer was found to produce 5-50 ng/0.05 ml of the virus-specific proteins at 6 to 8 days postinfection.

Animals↗
PubMedDate not supplied

[The isolation and characteristics of reassortants between the Lassa and Mopeia arenaviruses].

Reassortants with a mixed phenotype were produced by combined inoculation of Vero cells with Lassa and Mopeya viruses. These reassortants produced small plaques (Mopeya virus phenotype) and were not pathogenic for newborn mice (Lassa virus phenotype). The genotype of the reassortants was studied by dot hybridization experiments on filters using cDNA-probes differentiating genome segments of these viruses. The reassortants were shown to have Mopeya virus L-RNA and Lassa virus S-RNA.

Animals↗
PubMedDate not supplied

[Characteristics of 24S and 35S virus-specific RNA in cells infected with Newcastle disease virus].

The properties of 24S and 35S virus-specific RNAs of Newcastle disease virus were studied after denaturation. It was shown that 60-80% of 24S and 35SRNA consisted of agglomerates of molecules of virus-specific 18S RNA. Undissociable upon denaturation, 24S RNA contained mainly the same components as undenaturated RNA and consisted completely of sequences of virus-specifis 18S RNA. Undissociable 35S RNA contained no "heavy" heterogenous material present in the intact undenaturated RNA and 75% of it consisted os sequences of 18S virus-specific RNA. Some sequences present in undissociable 24S RNA were absent in undissociable 35S RNA. The aggregation of virus-specific na-transcripts and subsequent formation of covalent bonds between transcripts as well as possible formation of "solid" transcripts of the adjacent genes are discussed.

Newcastle disease virus↗
PubMedDate not supplied

[Virus-specific poli(A)-containing RNA-transcripts in cells infected with Newcastle disease virus].

The techniques of chromatography on poly (U)-cellulose and sedimentation and electrophoresis analysis were used to study poly(A)-containing virus-specific RNA of Newcastle disease virus. The poly(A)-containing molecules were shown to be present in approximately similar amounts (60-80%) in 18S, 24S, and 35S RNA. No poly(A)-containing molecules capable of interaction with poly(U) sepharose were found in 50S RNA. In 18S RNA there are 6 individual poly(A)-containing RNA-transcripts with molecular weights well correlating with those of virus proteins. The average size of poly(A) for 18S and 24S RNA is 60-70 nucleotide residues. In the sedimentation analysis of poly; A)-containing 24S and 35S RNA eluted from poly(U)-columns, some of the material sedimented in the zone of 18S RNA. The presence of complexes of two or several molecules with the sedimentation coefficient 18S in these RNA's is suggested.

Base Sequence↗