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Biomedical subjects

U Desselberger

Publications and source records attributed to U Desselberger.

At least 109 records · Page 6Linked to original sources
PubMed1987

Reassortment of human rotavirus possessing genome rearrangements with bovine rotavirus: evidence for host cell selection.

Mixed infections of secondary rhesus monkey kidney cells with human rotaviruses carrying rearranged genomes and with bovine rotavirus yielded a high percentage of reassortants. The genotypes of 511 plaque-purified clones raised in either MA104 or BSC-1 cells have been determined and the frequencies of different genotypes have been calculated. It was found that reassortants did not emerge at random; there was non-random association of certain genes; the cell line used to isolate reassortants influenced the result, i.e. host cell factors had a selective effect on a recombinational mixture.

Animals↗
PubMed1987

Biophysical characterization of rotavirus particles containing rearranged genomes.

Human rotaviruses containing rearranged genomes were found to package up to 1,800 additional base pairs in virus particles. The viruses compared were indistinguishable in respect of their particle diameters and their apparent S values. Particles containing rearranged genomes were found to be of a higher density than rotavirus particles containing a standard genome as determined by equilibrium density ultracentrifugation. The increase in density was directly proportional to the number of additionally packaged base pairs.

Biophysical Phenomena↗
PubMed1987

Heterogeneity of genome rearrangements in rotaviruses isolated from a chronically infected immunodeficient child.

Rotaviruses with genome rearrangements, isolated from a chronically infected immunodeficient child, were adapted to growth in BSC-1 cells. Preparations of viral RNA from fecal extracts showed a mixed atypical rotavirus RNA profile, which was due to the presence of at least 12 subpopulations of viruses grossly differing in genotype. Besides various forms of genome rearrangements involving segment 8-, 10-, and 11-specific sequences, reassortment in vivo was likely to have occurred during the emergence of these viruses. The protein products of viral genomes with various forms of segmental rearrangements seemed to be largely unaltered. Genome rearrangement is proposed to be a third mechanism directing the evolution of rotaviruses.

Animals↗
PubMed1986

The stiffness of dsRNA: hydrodynamic studies on fluorescence-labelled RNA segments of bovine rotavirus.

The sedimentation coefficients of dsRNA segments of bovine rotavirus were determined in the analytical ultracentrifuge. The eleven segments were separated by preparative gel electrophoresis, and isolated by elution from gel pieces. The RNA was labelled by the intercalating fluorescent dye ethidium bromide at a ratio bound dye per base pair between 0.003 to 0.018. The analytical ultracentrifuge was equipped with a fluorescence recording optics. Sedimentation coefficients could be determined with amounts of RNA as little as 8 ng. All sedimentation coefficients were extrapolated to zero-concentration, zero-dye binding, and zero-impurities from the preparative gel electrophoresis. The hydrodynamic model of flexible cylinders was applied for the interpretation of the sedimentation coefficients. All dsRNA segments of rotavirus (663-3409 base pairs) and the dsRNA5 of cucumber mosaic virus (335 base pairs) fit the model of a "worm-like" or flexible cylinder with a persistence length of 1125 A and a hydrated diameter of 30 A. The results are compared with data from the literature on the persistence lengths of the B- and Z-forms of dsDNA and of viroids.

Animals↗
PubMed1986

Genome analysis of species 3 adenoviruses isolated during summer outbreaks of conjunctivitis and pharyngoconjunctival fever in the Glasgow and London areas in 1981.

Genome analysis was performed on 125 adenovirus isolates from conjunctival swabs of patients with conjunctivitis obtained in Glasgow between 1981 and 1984. A summer outbreak in 1981 was mainly due to species 3 adenoviruses, of which genotype 3GB and five different genotypic variants cocirculated. Three species 3 variants were also observed in 1982. The genome changes of variants were located on physical maps of the Ad3 reference strain and found to be clustered near the ends of the adenovirus DNA (including the fiber area), whereas the hexon coding region was unaltered. In contrast to the genome heterogeneity observed among the species 3 adenoviruses collected in Glasgow in 1981 it was found that all 69 Ad3 isolates obtained from an outbreak of pharyngoconjunctival fever in a boarding school near London during the summer of 1981 possessed the 3GB genotype.

Adenoviridae Infections↗
PubMed1986

Genome analysis of human rotaviruses by oligonucleotide mapping of isolated RNA segments.

The genomes of adult diarrhoea rotaviruses isolated in different parts of China during winter outbreaks in 1983 and 1984 were compared by segmental oligonucleotide (ON) mapping. The RNA profiles of most of the isolates were indistinguishable but it was found that some corresponding RNA segments had identical or very closely related ON maps whereas others differed considerably. This finding can be taken to suggest that the strains compared may be genetically related by a natural reassortment event. The genomes of cocirculating group A rotaviruses isolated in Scotland during winter outbreaks in 1981/82 were also compared. The ON maps of corresponding RNA segment differed extensively irrespective of whether or not the segments comigrated on gels.

Adult↗
PubMed1985

Noncumulative sequence changes in the hemagglutinin genes of influenza C virus isolates.

Sequence analysis and comparison of hemagglutinin (HA) genes of different influenza C viruses isolated between 1947 and 1983 reveals that (1) the extent of difference among the HA genes is independent of the year in which these viruses were isolated and that (2) changes in the HA genes do not appear to accumulate with time. These results suggest that epidemiologically dominant variants of influenza C viruses do not emerge successively with time and that C virus variants derived from multiple evolutionary pathways cocirculate at any one time. Thus the epidemiology of influenza C viruses differs markedly from that of influenza A viruses, which is characterized by the emergence of successive variants. Based on the nucleotide sequence data, we propose different evolutionary models for influenza A and influenza C viruses.

Amino Acid Sequence↗
PubMed1985

Genome rearrangements of bovine rotavirus after serial passage at high multiplicity of infection.

After serial passage at high multiplicity of infection of standard bovine rotavirus in MA104 cells, different genome rearrangements occurred in which segment 5 was lost from the RNA profile and distinct additional bands of double-stranded (ds) RNA were found in positions on gels between segments 1 and 6. It was shown that some of the additional RNA bands contained segment 5-specific sequences. The additional RNA bands were transcribed in vitro to apparent full length. Analysis of the proteins synthesized in cells infected with viruses possessing rearranged genomes showed that in all cases the product of RNA segment 5, VP5, was missing; however, in one case an abnormal protein was observed which corresponded in size to the coding capacity of the mRNA transcribed from the additional genomic RNA band. Viruses with rearranged genomes could be plaque purified, and they grew in the absence of standard virus to titers comparable to those obtained from standard virus. In mixed infections of standard virus and virus possessing genome rearrangements, standard virus overgrew during passage at low multiplicity of infection whereas virus possessing genome rearrangements overgrew during passage at high multiplicity of infection.

Animals↗
PubMed1985

Rise per base pair in helices of double-stranded rotavirus RNA determined by electron microscopy.

Regular helices of double-stranded RNA occur in nature only as the genome of certain viruses. The structure of such double-stranded RNA helices has been little studied compared to that of DNA, but some X-ray crystallographic data (Arnott, 1970; Saenger, 1984) are available. The recent advent of sequence data of bovine rotavirus RNA (Dyall-Smith et al., 1983; Elleman et al., 1983; Ward et al., 1984) has enabled us to determine by direct measurement of electron micrographs the translation, or axial distance between base pairs in RNA duplexes. Using two different spreading conditions we obtained values of 2.79 +/- 0.10 and 2.80 +/- 0.11 A. These results are consistent with the 11-fold A RNA (Arnott, 1970; Rosenberg et al., 1976) proposed for the conformation of double-stranded RNA. We included both circular and linear molecules of phi X174 RF DNA in the same preparations, and the translations for these molecules were between 3.23 +/- 0.06 and 3.29 +/- 0.05 A. Thus, double-stranded RNA contained 1.16 to 1.17 times more nucleotides per unit length than DNA.

Animals↗
PubMed1985

Protein and nucleic acid analyses of influenza C viruses isolated from pigs and man.

The virus-coded proteins and the genomes of influenza C virus isolates obtained from Chinese pigs in 1981-1982 and of human influenza C virus strains isolated between 1947 and 1981 were compared. Using SDS polyacrylamide gel electrophoresis and one-dimensional peptide mapping we found the virus-coded proteins of the pig influenza C viruses to be similar to those of human influenza C virus strains. The sizes of the genomes of human and pig influenza C viruses were indistinguishable. Genome analysis by oligonucleotide (ON) mapping revealed that the genomes of the pig influenza C viruses were very similar to but not identical with those of human influenza C virus strains. ON changes were found scattered over the whole genome. ON mapping of isolated segments of several influenza C virus strains suggested that two pig strains (C/P/B/10/81 and C/P/B/32/81) are related by a reassortment event which is likely to have occurred in nature. The rate of genome variation in influenza C viruses seemed to be similar to that seen in influenza B, and slower than that recorded for influenza A viruses.

Animals↗
PubMed1985

Reassortment of human rotaviruses carrying rearranged genomes with bovine rotavirus.

Rotaviruses isolated from chronically infected immunodeficient children were previously shown to contain RNA yielding abnormal migration profiles on gels: normal RNA segments were lost or decreased in concentration, and additional bands of dsRNA were found which were derived (rearranged) from genome segments of lower molecular weight by concatemer formation. These viruses grew very slowly during passage in secondary rhesus monkey kidney cells. Upon superinfection with the tissue culture-adapted UK Compton strain of bovine rotavirus (BRV) extensive genome reassortment occurred. Clones with the following reassorted genome patterns were isolated: (i) RNA segments 5 or 6 of BRV were replaced by the corresponding RNA segments of human rotavirus; (ii) RNA segments 9 or 11 of BRV were replaced by different rearranged bands of RNA of human rotavirus; (iii) reassortants were observed containing more than one segment/rearranged band of human rotavirus RNA in different combinations. The reassortant viruses possessed functional proteins coded for by the genome segments and/or by rearranged bands of RNA of the human rotaviruses. Rearrangement of parts of the rotavirus genome may be a mechanism of evolution of these viruses.

Animals↗
PubMed1985

Influenza C virus RNA 7 codes for a nonstructural protein.

The complete nucleotide sequence of RNA segment 7 of influenza C/California/78 virus was determined by using cloned cDNA derived from viral RNA. The gene is 934 nucleotides long and possesses a long open reading frame which can code for a protein of 286 amino acids. Hybrid arrest translation experiments with the cloned cDNA fragment and poly(A)-containing RNA isolated from virus-infected cells showed that a 28,500-molecular-weight protein is coded for by RNA 7. Comparison of the proteins induced in the cell-free system and in virus-infected cells with those found in purified virus suggests that the 28,500-molecular-weight protein is a nonstructural protein.

Amino Acid Sequence↗
PubMed1984

Molecular epidemiology of human rotaviruses. Analysis of outbreaks of acute gastroenteritis in Glasgow and the west of Scotland 1981/82 and 1982/83.

The molecular epidemiology of rotavirus infections in Glasgow and the west of Scotland during 1981/82 and 1982/83 was investigated by electron microscopy, ELISA testing and RNA migration pattern analysis. In 1981/82, rotaviruses of both the 'long' and the 'short' electropherotype (in different variants) co-circulated from the onset throughout the winter peak of the outbreak. Approximately 80% of the children were infected during the first year of life. No differences in incidence were found between sexes. In 1982/83 the isolated rotaviruses were almost exclusively of the 'long' electropherotype (in different variants) and 36% of the children were infected beyond the first year of life. Rotaviruses of the 'long' electropherotype serologically were of subgroup II and serotype 1 and those of the 'short' electropherotype of subgroup I and serotype 2.

Acute Disease↗
PubMed1984

Rotavirus RNA segments sized by electron microscopy.

The RNA segments of bovine rotavirus (UK Compton strain) were measured by electron microscopy in mixtures containing phi X174 double-stranded DNA as an internal reference molecule. The numbers of base pairs per segment were calculated and compared with data obtained by other procedures (comparative RNA gel electrophoresis; co-electrophoresis of cDNAs in denaturing gels; sequencing).

Animals↗
PubMed1984

Genome analysis of influenza C viruses isolated in 1981/82 from pigs in China.

The genomes of influenza C viruses isolated from pigs in Beijing, China during 1981/82 and of human influenza C virus strains isolated between 1947 and 1981 were analysed by comparison of RNA migration patterns on gels and by two-dimensional oligonucleotide (ON) mapping. The genomes of the pig isolates were closely related to one another, though in part distinguishable by point mutations. They were similar to but more distantly related to the genomes of human influenza C viruses. The genome of the C/pig/Beijing/10/81 isolate differed from that of the C/pig/Beijing/32/81 isolate obtained on the same day at the same place by a number of mutations which were all located in RNA segments 1 and 2 as shown by ON mapping. This result suggests that the two isolates are genetically related by a reassortment event which is likely to have occurred in nature. The question whether or not pigs are a natural reservoir for human influenza C viruses cannot be answered at present.

Animals↗
PubMed1984

Polypeptide synthesis in MDCK cells infected with human and pig influenza C viruses.

MDCK cells were infected with six human influenza C virus strains (isolated between 1947 and 1981) and seven pig influenza C virus strains (isolated in 1981 and 1982) and the virus-specific polypeptides were compared by SDS-polyacrylamide gel electrophoresis and one-dimensional peptide mapping. The major structural polypeptides, i.e. glycoprotein (gp88), nucleoprotein (NP), and membrane protein (M), and one non-structural polypeptide were identified in all strains by radiolabelling infected cells with [35S]methionine. No differences in the electrophoretic migration of the M proteins or NS proteins were observed. The two earliest human isolates, C/Taylor/1233/47 and C/Great Lakes/1167/54, had faster migrating NP proteins, and another human strain, C/Georgia/1/69, displayed a faster migrating gp88. Minor differences in the one-dimensional peptide maps produced by partial digestion of the M proteins with V8 protease were observed between the human and pig isolates, while more marked differences were noted in the peptide maps of the glycoproteins of the C/Georgia/1/69, C/Yamagata/10/81 and C/Yamagata/11/81 viruses compared to the other human strains and the pig strains. The overall conclusion is that the proteins of human influenza C viruses isolated over a 35 year period and those of recent pig influenza C virus isolates are highly conserved.

Animals↗