Date of Award
1970
Degree Type
Thesis
Degree Name
Master of Science
Supervisor
John Robinson
Abstract
Bdellovibrio bacteriovorus strain 6-5-S exhibited a typical infection cycle when incubated with E. coli ML 35 (lac i-z*y ) in 0.025 M Hepes buffer, pH 7.8, supplemented with 0.002 M CaCl2*2H 0. Growth of Bdellovibrio occurred within a wide pH range, with the optimum being from 7.5 to 8.5. No growth occurred at pH 6.5. The broad pH range may occur because a buffer per se is not required for growth and multiplication. Bdellovibrio failed to multiply in a two-membered culture unsupplemented with Calf or Mg'+. The cations were required for growth of Bdellovibrio with viable and autoclaved host cells. Growth and multiplication of Bdellovibrio in a two-membered culture were assessed by various parameters, including increase in plaque forming units (PFUml, decrease in absorbance and release of materials absorbing at 260 mu. The increase in PFU/ml occurred before the lysis of the host cell suspension. With the onset of lysis, the amount and rate of release of materials absorbing at 260 mu increased in the two-membered culture. Since the ratio of the absorbance of the culture fluid at 280 and 260 mu also increased, amino acids or proteins were being released. No protein or B-galactosidase could be detected in the culture fluid of the two-membered culture. The infected E. coli cells were more permeable than uninfected cells to o-nitrophenyl-B-D-galactoside, the substrate for B-galactosidase, and to the fluorescent dye 8-anilino-l-naphthalenesulfonic acid. Since the total cellular protein decreased during parasitization, some of the protein must have been degraded. The growth and multiplication of Bdellovibrio in the presence of autoclaved E. coli cells does not appear to involve an intracellular life cycle. Bdellovibrio will also grow and multiply in the supernatant of autoclaved E. coli cells and in the presence of autoclaved Bacillus megaterium cells.
Recommended Citation
Crothers, Susan Fearn, "Interaction of Bdellovibrio Bacteriovorus and Host Bacteria" (1970). Digitized Theses. 5053.
https://ir.lib.uwo.ca/digitizedtheses/5053
