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A R Bellamy

Publications and source records attributed to A R Bellamy.

At least 55 records · Page 3Linked to original sources
PubMed1985

Rotavirus neutralizing protein VP7: antigenic determinants investigated by sequence analysis and peptide synthesis.

The rotavirus neutralizing antigen, VP7, is a 37,000-molecular-weight glycoprotein which is a major component of the outer shell of the virion. The amino acid sequence of VP7 for strain S2 (human serotype 2) and Nebraska calf diarrhea virus (bovine serotype) has been inferred from the nucleic acid sequence of cloned copies of genomic segment nine. Comparison of the amino acid sequences of these two VP7 proteins with those already determined for other rotavirus strains reveals extensive sequence conservation between serotypes with clusters of amino acid differences sited predominantly in hydrophilic domains of the protein. Six peptides have been synthesized that span the hydrophilic regions of the molecule. Antisera to these peptides both recognize the respective homologous peptides in a solid-phase radioimmunoassay and bind to denatured VP7 in a Western blot. However, none of the antisera either recognize virus or exhibit significant neutralizing activity, indicating that these peptide sequences are not available on the surface of the virus.

Amino Acid Sequence↗
PubMed1985

Diagnosis of rotavirus infection with cloned cDNA copies of viral genome segments.

The diagnostic potential of cloned cDNA copies of human rotavirus (strain WA) genome segments for the detection of rotavirus in clinical specimens has been determined. A hybridization assay in which a mixture of 32P-labeled cDNAs representing the 11 rotavirus segments was used as a probe compared favorably with three frequently used diagnostic tests for rotavirus in terms of both specificity and sensitivity. Significantly, clinical isolates could be readily distinguished when cloned cDNA copies of individual genome segments were used independently as a probe. In assays in which genome RNA from rotaviruses of known subgroups and serotypes were tested, cloned probes that encode nonstructural viral proteins hybridized efficiently to genome RNAs of all strains, whereas cloned probes corresponding to genome segments 6 and 9 exhibited the potential for differentiating strains of different subgroups and serotypes. Cloned cDNA copies of rotavirus genome segments therefore offer considerable potential for improved general diagnosis of rotavirus in clinical specimens, as well as for epidemiological studies in which virus isolates can be distinguished on the basis of nucleotide sequence homology of individual genome segments.

Cloning, Molecular↗
PubMed1984

Nucleotide sequence of the dsRNA genomic segment 7 of Simian 11 rotavirus.

A full length cDNA copy of dsRNA segment seven of Simian 11 rotavirus has been obtained by standard molecular cloning techniques. Segment seven codes for the non-structural viral protein NCVP4 and is 1104 nucleotides in length with putative 5'- and 3'- terminal non-coding regions of 25 and 134 residues respectively. The longest open reading frame of 315 codons extends from nucleotide 26 to 970 inclusive. However, the presence nearby of two other AUG codons makes it unclear which codon is used for initiation. The second AUG conforms to the Kozak consensus sequence and if utilised, would yield a protein 312 amino acids in length with a nett charge at pH7 of -2.5. Determination of the gene 7 sequence indicates that terminal sequence conservation among rotavirus gene segments is limited to three and two nucleotides at the 5' and 3' ends of the plus strand, respectively.

Amino Acid Sequence↗
PubMed1984

Reovirus RNA transcriptase: evidence for a conformational change during activation of the core particle.

Reovirus cores contain an RNA transcriptase capable of synthesizing messenger RNA. When cores are suspended in 1 X SSC at 37 degrees they are quiescent and synthesize no product, but in the presence of the components of an RNA transcriptase reaction mixture they actively synthesize mRNA. Photochemical crosslinking has been used to investigate the arrangement of RNA and protein in both "quiescent" and "active" cores. Irradiation induces the formation of a noncovalent RNA:protein complex in "quiescent" but not in "active" cores. This difference is attributed to a conformational change in the reovirus core which results from the transition between the "quiescent" and "active" states of the particle.

Enzyme Activation↗
PubMed1984

Comparative sequence analysis of rotavirus genomic segment 6--the gene specifying viral subgroups 1 and 2.

Cloned DNA copies of rotavirus genomic segment 6 from simian 11 (subgroup 1) and human strain Wa (subgroup 2) rotaviruses have been used to determine the nucleotide sequences of the gene that determines viral subgroup specificity. Both genomic segments are 1,356 nucleotides in length and possess 5'- and 3'-terminal untranslated regions of 23 and 142 nucleotides, respectively. The inferred amino acid sequence reveals VP6 to be a polypeptide of 397 amino acids in which more than 90% of the amino acid sequence is conserved between the two viruses. There are 34 amino acid changes between the subgroup 1 and 2 polypeptides, most clustered in three regions of the molecule at residues 39 through 62, 80 through 122, and 281 through 315.

Amino Acid Sequence↗
PubMed1983

Serotype-specific glycoprotein of simian 11 rotavirus: coding assignment and gene sequence.

Cloned DNA copies of the double-stranded RNA genomic segments of simian 11 rotavirus have been used to determine the coding assignment for VP7, the type-specific antigen of this virus. Translation of hybrid-selected mRNAs in an in vitro system supplemented with canine pancreatic microsomes permitted VP7 to be assigned to segment 9 and the two nonstructural viral proteins NCVP4 and NCVP3, to segments 7 and 8, respectively. Hybridization of cloned DNA probes for segments 7-9 with the corresponding segments of human rotavirus Wa confirmed these assignments. The complete nucleotide sequence of gene 9 has been determined. The deduced amino acid sequence reveals VP7 to be 326 amino acids in length with two NH2-terminal hydrophobic regions and a single glycosylation site at residues 69-71.

Amino Acid Sequence↗
PubMed1983

Coding assignment and nucleotide sequence of simian rotavirus SA11 gene segment 10: location of glycosylation sites suggests that the signal peptide is not cleaved.

A cloned DNA copy of simian rotavirus SA11 genomic segment 10 was used to confirm the assignment of the nonstructural glycoprotein NCVP5 to this gene. Determination of the nucleotide sequence for gene 10 indicated that NCVP5 is 175 amino acids in length and has an N-terminal hydrophobic region with the characteristics of a signal sequence for membrane translocation. Unexpectedly, this region was also the location for the only two potential glycosylation sites within the molecule, asparagine residues 8 and 18. The carbohydrates carried by NCVP5 were of the high-mannose type, Man9GlcNAc and Man8GlcNAc, with the mannose 9 species predominating; no complex oligosaccharides were present. If these asparagine residues are the sites for carbohydrate attachment, this implies that cleavage of the putative signal peptide does not occur during the maturation of this nonstructural glycoprotein.

Amino Acid Sequence↗
PubMed1982

A general strategy for cloning double-stranded RNA: nucleotide sequence of the Simian-11 rotavirus gene 8.

Using Simian-11 rotavirus RNA, a strategy has been developed for the production of full length cloned copies of the genes of double-stranded (dsRNA) viruses. Genomic RNA segments were polyadenylated and reverse transcribed to yield a mixture of full length cDNA copies of both possible polarities. The cDNAs were annealed, filled in to complete any partial copies, tailed and inserted into the PstI site of pBR322 using dG/dC tailing. Cloned rotavirus cDNA gene copies were assigned to genomic RNA segments by Northern hybridization. The complete sequence of gene 8 which codes for NCVP3, a non-structural protein of SA11 rotavirus, was determined from a cloned gene copy. It is 1059 bases in length and has an open reading frame which could code for a protein containing 317 amino acids. The apparent 5' and 3' terminal non coding regions are 46 and 59 bases in length, respectively. The sequence ATGTGACCOH at the 3' end of the plus strand is conserved in four of the eleven genes examined. The cloning procedures used should be generally applicable to viruses with segmented dsRNA genomes.

Base Sequence↗
PubMed1982

Sequence diversity of human rotavirus strains investigated by northern blot hybridization analysis.

Rotavirus genomic RNAs, derived from a series of human isolates that exhibit variability in the pattern of migration of the double-stranded RNA on polyacrylamide gels, were transferred to diazobenzyloxymethyl paper, and their sequence diversity was investigated. Hybridization of cDNA probes prepared from the 11 segments of rotavirus RNA indicated that considerable sequence diversity exists among these viruses. Under conditions of both low and high stringency, hybridization analysis of virus collected between 1975 and 1980 suggested that the variation among rotavirus strains may have occurred by a process involving both "drift" and "shift" in the sequence of the rotavirus genomic segments.

Base Sequence↗
PubMed1982

Sequence relationships between the genome segments of human and animal rotavirus strains.

The sequence relationships of a range of cultivable and noncultivable human and animal rotaviruses were investigated by hybridization of rotavirus cDNA probes to genomic RNAs immobilized on diazobenzyloxymethyl paper. Under conditions of low stringency (34% base mismatch tolerated) most genome segments exhibited partial homology except for genes 4 and 5. In contrast, under more stringent conditions of hybridization in which no more than 8% base mismatch was tolerated, few segments exhibited homology. Generally the human and animal rotaviruses were found to possess distinct nucleic acid sequences that exhibit only a low order of sequence relatedness. These results are consistent with the notion that both cumulative changes in nucleic acid sequences and the interchange of segments may be involved in the evolution of distinct rotavirus strains.

Animals↗
PubMed1981

Extraction of rotavirus from human feces by treatment with lithium dodecyl sulfate.

A procedure has been developed for the isolation of rotavirus from human fecal specimens based on the resistance of the virus to treatment with cold 1% lithium dodecyl sulfate at neutral pH. A single detergent treatment of fecal material followed by low- and high-speed centrifugations yielded a virus suspension of sufficient purity for viral ribonucleic acid to be analyzed directly by electrophoresis on polyacrylamide gels.

Detergents↗
PubMed1980

Subunit structure of the reovirus spike.

Cross-linking reovirus spike protein with the bifunctional reagent dimethyl suberimidate revealed that each spike was composed of a pentameric aggregate of polypeptide lambda 2.

Cross-Linking Reagents↗
PubMed1979

Two strains of human rotavirus in Auckland.

Polyacrylamide gel electrophoresis of human rotavirus RNA has identified at least two distinct strains of virus currently circulating in Auckland. The sensitivity of the method both for detecting rotavirus infection and for identifying variation in rotavirus strains is discussed.

Diarrhea↗
PubMed1978

Virus accumulation by the rock oyster Crassostrea glomerata.

The accumulation of virus by the New Zealand rock oyster Crassostrea glomerata has been studied in a static seawater system using radioactively labeled reovirus type III and Semliki Forest virus. The uptake of virus was found to be less rapid than for the bacterium Escherichia coli and to be unaffected by the presence of the marine alga Dunaliella primolecta in the seawater. Accumulation was dependent on virus concentration, with saturation achieved at 4 X 10(10) reovirus particles per oyster, implying that an oyster possesses a large but finite number of sites for virus adsorption. When the rates of uptake of two viruses of similar size but differing surface properties were compared, the rate of accumulation of the lipoprotein-enveloped Semliki Forest virus was found to be less than that for the protein-enclosed reovirus. This observation, together with the finding that the oyster shell has a strong affinity for virus, suggests that surface properties, rather than size, are the principal factors governing the accumulation of viruses by filter-feeding marine bivalves.

Adsorption↗