Date of Award:

5-1-1969

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Bacteriology

Committee Chair(s)

Frederick J. Post

Committee

Frederick J. Post

Committee

Gerald M. Baker

Committee

Rex S. Spendlove

Abstract

The sheath forming bacterium, Sphaerotilus natans is generally considered a nuisance organism. It is a causative agent of bulking sludge as well as the nuisance in commercial fishing areas. A unique characteristic of the bacterium is its coherent sheath. The formation, shape, and growth of the cell and sheath was observed by using seven inhibitors: neomycin, streptomycin, chloramphenicol, penicillin, sodium azide, acridine orange, and phenethyl alcohol. In the study, minimal concentration of inhibitors was used to determine their effect on the cell and its sheath. In many cases, the sheaths developed abnormally, and cells appeared fragmented and isolated as if the sheath had not formed or had broken up. Inhibition of all agents was proportional to the increase in the concentration of inhibitors as measured by comparison of dilutions of the organisms on the inhibitor-medium and a control. The inhibitors acted as bactericides at low concentrations and bacteriostatic agents at high concentrations. The denser the inoculum of S. natans on the inhibitor-Stokes medium, the greater the chance that the organism would adapt to the environment in which it grew. The inhibitors apparently produce gene mutations and/or metabolic interference of the cell by giving the appearance of abnormal morphology.

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