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D L Mould

Publications and source records attributed to D L Mould.

16 recordsLinked to original sources
PubMed1984

Comparison of cell surface antigen extracts from two serotypes of Pasteurella haemolytica.

Cells of Pasteurella haemolytica serotypes A1 and A6 were extracted with sodium salicylate and the chemical and antigenic composition of both extracts determined. The extracts were concentrated by ultrafiltration and the serotype antigen, measured by the indirect haemagglutination test, was estimated to have a molecular weight between 100 000 and 300 000. The chemical composition of sodium salicylate extracts (SSEs) from both serotypes was similar, having protein, carbohydrate, fatty acid and phosphorus present in the ratio 10:1:0.5:0.1. SDS-PAGE of both SSEs gave similar profiles with at least 48 bands present. These results suggest that sodium salicylate removes the outer membrane of P. haemolytica. Crossed immunoelectrophoresis indicated that a major serotype-specific antigen was present in SSEs of both strains. This antigen was extracted from the SSE with hot phenol/water and analysed by gas chromatography. The sugar composition of A1 and A6 phenol/water extract (PWE) was qualitatively identical although some differences in proportions were observed. A1 and A6 PWE antigens protected mice against homologous serotype challenge and A6 PWE protected against heterologous (A1) challenge.

Animals↗
PubMed1984

Adaptation of the guaiacol (peroxidase) test for haptoglobins to a microtitration plate system.

The optimal operational method was determined for performance of an adapted guaiacol test in microtitration ELISA plates for quantitative detection of haptoglobins in sheep serum. The test correlated well with assay on Sephadex G100 but was more sensitive, though with lowered reproducibility, at low levels of haptoglobin. The modified test permits both rapid testing of large numbers of samples and the calculation of results using a simple computer program.

Animals↗
PubMed1983

Serum protein changes in grass sickness.

Polyacrylamide gel electrophoresis was used to compare serum taken from ponies before and during clinical illness confirmed as grass sickness. A consistent rise in the level of haptoglobin was seen in serum from animals which had shown symptoms for more than two days. Serum albumin was also shown to have altered mobility at the onset of clinical disease. Estimation of the haemoglobin-binding capacity confirmed the haptoglobin increase. This haptoglobin has been purified and some of its properties determined. In contrast to the situation in acute inflammatory conditions no other acute-phase proteins increased to a significant extent in grass sickness. It is concluded that the neurotoxin known to be present in sera of animals experiencing acute grass sickness cannot itself be detected by polyacrylamide gel electrophoresis but may be bound to serum albumin.

Animals↗
PubMed1977

Experimental studies of neurotoxic activity in blood fractions from acute cases of grass sickness.

Plasma, serum and cells were prepared from blood taken from acute cases of grass sickness, and plasma was fractionated by gel filtration and salt precipatation. These preparations were all tested for neurotoxic activity by injection into ponies. Plasma and serum were found to produce the neurohistological changes seen in grass sickness, as was a plasma protein fraction of molecular weight 30,000 or greater. Activity was retained following storage at--75 degrees C for 15 months. Plasma given orally to a pony produced no detectable effect, nor was activity demonstrated following the injection of plasma or the high molecular weight fraction to mice, rats, guinea-pigs or rabbits.

Animals↗
PubMed1976

The comparison and characterisation of glycolytic mycoplasmas isolated from the respiratory tract of sheep.

Nine strains of glycolytic mycoplasmas isolated from the respiratory tract of apparently healthy sheep, pneumonic sheep and sheep with pulmonary adenomatosis (SPA) were compared with a Queensland strain (Y98) of Mycoplasma ovipneumoniae. All strains were very similar in their reactions in 14 biochemical tests and in their sensitivities to optochin, digitonin, sodium polyanethol sulphonate, and 11 antibiotics. Polyacrylamide-gel electrophoresis and serological cross-reactions by the agar-gel double diffusion, metabolic inhibition (MI) and growht-inhibition (GI) tests also showed that all strains could be classified as M. ovipneumoniae. The MI and GI tests, however, showed considerable intraspecific differences among strains, with apparent polarisation of SPA strains and non-SPA strains at opposite ends of the antigenic spectrum. Two representative strains were tested by the MI test against antisera to 39 mycoplasma species or serogroups, with negative results.

Aerobiosis↗
PubMed1975

Protein electrophoretic pattern of Pasteurella haemolytica.

Electrophoresis in polyacrylamide gels of the constituent proteins of the 12 serotypes and an untypable strain of Pasteurella haemolytica showed a pattern of bands that divided the group into two. This division conformed to the A and T biotype groupings of Smith (1959) although the serotype A9 showed only minor band difference from the three T serotypes 3, 4 and 10. It was not possible by this method to separate all the type strains from each other by the specific recognition of the patterns of protein mobilities produced.

Bacterial Proteins↗