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J R Bell

Publications and source records attributed to J R Bell.

At least 73 records · Page 4Linked to original sources
PubMed1984

Primary structure of the neutralization antigen of simian rotavirus SA11 as deduced from cDNA sequence.

DNA sequences complementary to the double-stranded RNA coding for the neutralization antigen (glycoprotein VP7) of simian rotavirus SA11 have been cloned. The VP7 gene consists of 1,062 nucleotides, containing an uninterrupted coding sequence of 978 nucleotides which specifies a glycoprotein of 326 amino acids. The significance of a second possible initiation site 30 nucleotides downstream from the first is discussed. Partial amino acid sequence of this glycoprotein showed unequivocally that the cloned segment (segment 9) codes for glycoprotein VP7 of SA11. The resulting amino acid sequence contained only one carbohydrate acceptor site. Possible sites of membrane interaction and antigenic determinants are discussed based on the analysis of the hydrophobicity and hydrophilicity profiles of VP7.

Amino Acid Sequence↗
PubMed1983

Sequence analysis of two mutants of Sindbis virus defective in the intracellular transport of their glycoproteins.

We have sequenced the complementary DNA corresponding to the genes encoding the viral glycoproteins of ts10 and ts23, mutants of Sindbis virus defective in the intracellular transport of their glycoproteins, and of revertants of these mutants. These studies have been augmented by direct amino acid sequencing of the amino-terminal regions of the glycoproteins of several virus strains. By comparing the deduced amino acid sequence with that of Sindbis HR virus, the parental strain of these mutants, and with the sequence of the revertants, we found ts23 to have a double mutation in glycoprotein E1, while ts10 was a single mutant in the same glycoprotein. In each case reversion to temperature insensitivity occurred by changes at the same site as the mutation, in two cases restoring the original amino acid and in the third case substituting an homologous amino acid (arginine in place of lysine). The three mutations were far apart from each other in the protein, suggesting that the three-dimensional conformation is very important for the correct migration of the glycoproteins from the rough endoplasmic reticulum to the plasma membrane. The sequence data also reveal that a number of other changes have occurred in the various virus strains during mutagenesis or passage.

Amino Acid Sequence↗
PubMed1983

Isolation and chemical characterization of a melanoma-associated proteoglycan antigen.

Many melanoma-associated antigens have been identified by monoclonal antibodies. One of these monoclonal antibodies, O1-94-45, binds only to melanomas, nevus cells, some astrocytomas, and fetal epitheloid cells. There are approximately 100,000 cell surface antigens per melanoma cell with an association constant of 3 X 10(8) M-1. The antigen is efficiently extracted from the membrane only in the presence of detergent and is, therefore, bound by hydrophobic forces. However, it is also shed into the culture supernatant during normal cell growth. The two components of the O1-95-45 antigen are a chondroitin sulfate proteoglycan (CSP, greater than 500,000 Da) and a glycoprotein gp260 (260,000 Da, pI 6.9). CSP contains chondroitin sulfate and N-linked and O-linked oligosaccharides. Only N-linked saccharides were associated with gp260. The antigenic site is expressed on both components and is heat-sensitive. Since the CSP was converted to gp260 by chondroitinase, the protein cores of the two molecules are the same or similar. For more detailed study the O1-95-45 antigen was purified by immunoaffinity chromatography. The amino acid composition of the purified antigen was relatively polar with an unusually high Leu content and low Lys content. Initial attempts to sequence the antigen were unsuccessful probably due to a blocked N-terminus. CSP and gp260 were partially separated by gel filtration chromatography, and both were found to carry the O1-95-45 antigenic determinant. Three other monoclonal antibodies were found to bind the purified antigen at a site or sites different from the O1-95-45 epitope and one other monoclonal antibody may bind at the same site. Two of these antibodies were used for a double determinant immunoassay.

Amino Acids↗
PubMed1983

Structural proteins of Western equine encephalitis virus: amino acid compositions and N-terminal sequences.

The structural proteins of Western equine encephalitis virus, a member of the alphavirus group, have been characterized by the determination of their amino acid compositions and by N-terminal sequence analysis. More than 60 residues of the N-terminal sequences of each of the envelope glycoproteins have been determined. A comparison of these sequences with the previously determined sequences of two related alphaviruses. Sindbis virus and Semliki Forest virus, strongly supports the view that all three viruses have evolved from a common ancestor and provides information on the pattern of this evolution. The analysis of the capsid proteins of Western equine encephalitis virus shows that the nucleocapsid of this virus can accommodate a considerable degree of variability in its protein component and that at least some regions of alphavirus capsid proteins show more extensive differences between different viruses than do the envelope glycoproteins.

Amino Acid Sequence↗
PubMed1981

In vivo NH2-terminal acetylation of Sindbis virus proteins.

The in vivo incorporation of exogenous radioactive acetate into two proteins of Sindbis virus, the capsid protein and PE2, is described. Under appropriate labeling conditions, 40-50% of the label in the capsid protein is found in an N-acetyl group which constitutes the NH2-terminal modification of this blocked protein. The incorporated radiolabeled acetate was useful in the purification and analysis of peptides derived from the NH2-terminus of the capsid protein, and from these peptides the NH2-terminal sequence of the protein was determined to be N-acetyl-Met-Asx-, with the asx group most likely asparagine. The analysis of a peptide derived from the NH2-terminus of PE2 and containing 45% of the acetate-derived label in this protein leads us to conclude that at least a significant fraction of PE2 is also blocked by N-acetylation.

Acetates↗
PubMed1978

Amino-terminal sequence analysis of the structural proteins of Sindbis virus.

The structural proteins of Sindbis virus, an enveloped virus which belongs to the Togavirus family, have been subjected to automated Edman degradation using improved techniques. Extensive NH2-terminal sequences of about 50 residues were determined for each of the two membrane glycoproteins. In both cases the NH2 terminus of the molecule was found to be similar in composition to typical water-soluble proteins. The viral capsid protein was found to have a blocked alpha-amino group. This is consistent with other observations that viral proteins derived from the NH2 terminus of precursor molecules are often blocked.

Amino Acid Sequence↗
PubMed1975

Results of surgery for Crohn's disease in the Glasgow region, 1961-70.

During the period 1961-70, 283 patients in the Glasgow region have been studied with regard to the outcome of 418 surgical procedures performed for Crohn's disease. Resection was followed by an overall recurrence rate of 33 per cent, but in disease confined to the large bowel the rate was 18 per cent. Exploratory operations and bypass procedures were followed by a recurrence rate of 70 per cent. Evidence is provided that recurrence following bypass procedures for small bowel disease and ileocolitis occurs at a later stage than after exploratory operations alone. By the end of the study 77 per cent of patients in this series had required one or more resections.

Crohn Disease↗
PubMed1975

Epidemiological aspects of Crohn's disease in Clydesdale 1961-1970.

A retrospective study of Crohn's disease has been carried out in Clydesdale covering the decade 1961-1970. Three hundred and fifty-seven patients had acceptable evidence of either acute ileitis or of chronic granulomatous bowel disease. Of those fulfilling the criteria for inclusion in the study of chronic disease, 95% had accurate pathological and/or operative documentation of the lesions. Overall, females outnumbered males by 1-6:1 but colonic disease alone tended to affect females, particularly those over the age of 50. The annual incidence of all forms of the chronic disease in both sexes has increased during the decade, but diagnosis of colonic disease alone increased two-fold in the latter half of the study.

Acute Disease↗