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S Wootton

Publications and source records attributed to S Wootton.

11 recordsLinked to original sources
PubMed2001

Antigenic importance of the carboxy-terminal beta-strand of the porcine reproductive and respiratory syndrome virus nucleocapsid protein.

Five domains of antigenic importance were previously mapped on the nucleocapsid protein (N) of the porcine reproductive and respiratory syndrome virus (PRRSV), and a domain comprised of the 11 C-terminal-most amino acids (residues 112 to 123) was shown to be essential for binding of N-specific conformation-dependent monoclonal antibodies (MAbs). In the present study, the importance of individual residues within this C-terminal domain for antigenicity was investigated using eight different mutant constructs of N expressed in HeLa cells. Single amino acid substitutions were introduced into the C-terminal domain of the N protein, and the significance of individual amino acids for MAb reactivity was determined by immunoprecipitation. None of the MAbs tested recognized the mutant with a leucine-to-proline substitution at residue 114 (L114P), while V112P, R113P, R113D, I115P, and R116P reduced MAb binding significantly. Conversely, substitution of amino acids at positions 118 (T118S) and 121 (P121A) had little effect on MAb binding. Secondary-structure predictions indicate that amino acids 111 to 117 form a beta-strand. In view of the fact that replacement of beta-strand-forming amino acids with proline elicited the greatest effect on MAb binding, it appears that secondary structure in the C terminus of the N protein is an important determinant of conformational epitope formation. While the crystal structure of the PRRSV N protein remains to be determined, results from these studies broaden our understanding of the secondary structures that make up the PRRSV N protein and shed some light on how they may relate to function.

Amino Acid Sequence↗
PubMed2000

Full-length sequence of a Canadian porcine reproductive and respiratory syndrome virus (PRRSV) isolate.

Presently, one of the most economically important pathogens affecting swine is the porcine reproductive and respiratory syndrome virus (PRRSV). This virus is prevalent in herds throughout the world and continues to pose a significant threat as newer and more virulent disease phenotypes emerge. In this report we describe the full-length nucleotide sequence of a Canadian PRRSV isolate, designated PA8. A consecutive sequence of 15,411 nucleotides was obtained from a set of overlapping cDNA clones. In order to determine the extent of genetic variation among isolates recovered from swine in Canada and the US, as well as to understand the molecular mechanisms governing the evolution of PRRSV, the full-length sequence of PA8 was compared with that of two US isolates, VR2332 and 16244B. The genomic sequence of PA8 shared 98.2% and 99.2% identity with 16244B and VR2332, respectively. The untranslated regions (UTR) at the 5' and 3' ends of the genome were very well conserved. Notable exceptions include an eight nucleotide difference at the 5' end of the 5' UTR of VR2332 relative to PA8 and 16244B and a two nucleotide difference in the 3' UTR of PA8 relative to VR2332 and 16244B. In contrast to PA8 and VR2332, 16244B possessed two nucleotide differences within the RNA pseudoknot structure of the ribosomal frameshift region between open reading frame (ORF)1a and ORF1b. Amino acid differences were distributed throughout the genome, however they appeared to be most extensive in Nsp1beta and ORF5 of the nonstructural and structural coding regions, respectively, suggesting that the evolutionary pressure to conserve these viral genes is somewhat lower.

3' Untranslated Regions↗
PubMed1992

Increased resting energy expenditure in childhood asthma: does this contribute towards growth failure?

In order to determine whether or not there was a relationship between disorders of growth in children suffering from asthma and either increased resting energy expenditure or inadequate energy intake, a group of 34 children suffering from perennial symptoms were studied. A control group matched with the asthmatic children for sex and fat free mass were similarly studied. The children kept seven day records of weighed food intake. Basal metabolic rate was measured on one occasion in the fasted state by means of indirect calorimetry using the ventilated hood technique. The asthmatic children kept a 28 day record of peak expiratory flow rates, asthma symptoms, and medication usage. The asthmatic children expended significantly more energy at rest than their matched controls in absolute terms (14%). There was no correlation between height or height SD score and any parameter of energy balance. The causes of these finding are as yet speculative.

Asthma↗
PubMed1990

Excessive faecal losses of vitamin A (retinol) in cystic fibrosis.

Vitamin A (retinol) deficiency is a recognised complication of cystic fibrosis and is presumed to be a consequence of an impairment in the digestion and absorption of dietary fats. The dietary intake of fat and retinol was assessed from a seven day weighed food intake in 11 subjects with cystic fibrosis and 12 matched controls. Faecal excretion of retinol and fat were measured from three day stool collections. There was little difference between the two groups in the intake of fat or retinol equivalents. When studied the subjects with cystic fibrosis were clinically stable and the apparent absorption of fat was not significantly different to that in the controls. There was a significant increase in the faecal losses of retinol in cystic fibrosis, which was unrelated to the degree of fat in the stool. In cystic fibrosis the median retinol recovered in the stool was 40% of the intake, compared with 1.8% in the controls. It is concluded that there is a specific defect in the handling of retinol by the gastrointestinal tract in cystic fibrosis, which may be unrelated to the digestion and absorption of dietary fat.

Adolescent↗