Browsing by Person "Coleman, G."

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A comparative study of the formation of extracellular proteins by Aeromonas salmonicida at two different temperatures
(Wiley, 1987-04) Fyfe, Lorna; Coleman, G.; Munro, A. L.
Aeromonas salmonicida was grown in a supplemented 3% (w/v) tryptone soya broth medium at 10 degrees C, a temperature at the lower end of the range over which furunculosis has been observed to occur in the field, and 25 degrees C, the optimum temperature for growth. Similar bacterial densities in the range 2.35 +/- 0.05 mg dry wt/ml were achieved in the two cultures at the beginning of the stationary phase of the growth cycle, after 125 h at 10 degrees C and 18 h at 25 degrees C. At this point, at the higher temperature 1.5 times more exoprotein was formed, 80 +/- 2.8 micrograms/ml compared with 54 +/- 1.7 micrograms/ml. Exoprotein contained the same proportion of haemolysin at both temperatures and twice as much protease at the higher temperature. The most marked difference was in an unidentified 100 kD protein which was formed in a 10-fold greater amount at 10 degrees C.
A comparison of the characteristics of extracellular protein secretion by a Gram positive and a Gram negative bacterium
(Plenum Press, 1987) Coleman, G.; Abbas, A.; Sutherland, J.; Fyfe, Lorna; Finley, A.; Chaloipka, J.; Krumphanzi, V.
A comparison of the distribution of extracellular proteins produced by the protease-secreting organism Aeromonas salmonicida during aerobic and anaerobic growth
(1986) Fyfe, Lorna; Coleman, G.; Munro, A. L.
Aeromonas salmonicida was grown aerobically and anaerobically in supplemented 3% (w/v) tryptone soya broth medium for 24 h at 25 degrees C. Although the bacterial density achieved was 4.9 times higher in the aerobic culture, the exoprotein produced per unit of bacterial dry weight was only 1.9 times higher than in the anaerobic culture. However, the protease activity of the exoprotein showed a marked reduction anaerobically, being only one-tenth of that of the exoprotein produced aerobically. This finding was consistent with the differing SDS-PAGE patterns of the extracellular proteins from the two cultures, which also showed marked loss and reinforcement of other, as yet unidentified extracellular products.
A study of the pathological effect of isolated Aeromonas salmonicida extracellular protease on Atlantic salmon, Salmo salar
(Wiley, 1986-09) Fyfe, Lorna; Finley, A.; Coleman, G.; Munro, A. L. S.
A comparison was made between the effects of Aeromonas salmonidda extracellular protease and total extracellular products (ECP) following intramuscular injection into juvenile Atlantic salmon, Salmo salar L. Thus, 20, 10, 5, 2.5 and 1.5 units of salt-free protease in 0.2 ml water were compared with ECP preparations with the same levels of proteolytic activity. The highest concentration of ECP produced a gross pathology with a large furuncular lesion 36 h after injection. The corresponding protease preparation had a lesser effect, although a furuncle was formed and tissue liquefaction was produced. These effects were less marked with reduced concentrations. At the lowest level studied, no significant effect was observed with protease alone but ECP (0.8 _g of protein) produced a small, characteristic lesion similar to that achieved with 5 units of isolated protease.
Aeromonas salmonicida extracellular virulence factors: The common components [Project Report]
(International Council for the Exploration of the Sea. Maritime Committee, 1986) Coleman, G.; Fyfe, Lorna
Identification of major common extracellular proteins secreted by Aeromonas salmonicida strains isolated from diseased fish
(1987-04-01) Fyfe, Lorna; Coleman, G.; Munro, A. L.
Ten different strains of Aeromonas salmonicida that were isolated from diseased fish were grown under identical conditions (24 h at 25 degree C) in 3% (wt/vol) tryptone soya broth medium supplemented with vitamins and inorganic ions. In each case the extracellular proteins that were formed were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it was found that there were two significant common components, one with a molecular weight of 70,000 and the other with a weight of 56,000. Application of enzyme purification techniques to the supernatant fraction proteins of a culture of one of the strains resulted in the isolation of a 70-kilodalton (kDa) component, which was found to be a serine protease, and a 56-kDa component, which was hemolytic to trout erythrocytes. Rocket immunoelectrophoresis with rabbit antibodies to the isolated protease and hemolysin showed the same antigenic components in the supernatant fractions of all the cultures. These activities were assayed, and protease activity was found to vary by a factor of three, from 59 to 195 U/ml, while the range of hemolytic activity was over a narrow band, from 28 to 43 U/ml. There was an inconsistency between the immunoelectrophoretic and direct assay data in only one case. This indicated the presence of additional hemolytic activity, in addition to the 56-kDa component. The detection of large amounts of the same protease and hemolysin, two potent degradative activities, in a random series of strains of A. salmonicida suggests that they may be obligatory virulence factors in the development of furunculosis.
The combined effect of isolated Aeromanas salmonicida protease and haemolysin on Atlantic salmon, Salmo salar L. compared with that of total extra-cellular products preparation
(Wiley, 1988-01) Fyfe, Lorna; Coleman, G.; Munro, A. L. S.