First Advisor

Mary Taylor

Term of Graduation

Spring 1998

Date of Publication

1998

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Biology

Department

Biology

Language

English

Subjects

Vibrio cholerae -- Effect of temperature on, Cholera -- Environmental aspects

Physical Description

1 online resource (2, iv, 83 pages)

Abstract

Vibrio cholerae has long been recognized as the causative agent of the disease cholera, but what has only become evident in recent years is the role of the environment in cholera. The cholera bacterium is found autochthonously in the marine and estuarian environment, and if there is any hope of controlling the disease the environmental aspects must be understood.

The central questions addressed in this study were how bacterial survival was influenced by temperature and the role that available nutrients play in V. cholerae survival. Survival of three different V. cholerae strains [classical (01); El Tor (01), and El Tor (0139)] grown on agar plates of Davis minimal salts or Luria medium was examined after incubation at -12, 4, 8, 10, 20, 22, 30, 40, 44, or 50 °C for 48 hours followed by incubation at 35 °C for 48 hours. Initial cultures were grown at 35 °C in Luria broth or Davis minimal broth, then diluted, plated, and incubated at various temperatures. To examine the influence of nutrients, four experiments were done with each strain. The first was a transfer of the organisms from high nutrient conditions to high nutrient conditions. The second was a transfer from high nutrient conditions to low nutrient conditions. Third was a transfer from low nutrient conditions to high nutrient conditions, and last was a transfer from low nutrient conditions to low nutrient conditions.

In summary, all strains survived in higher numbers under conditions with high nutrients; however, survival was substantial even in the minimal nutrient conditions.

The optimum growth and survival temperature for all of the strains was between 20 °C and 40 °C. When plated from the exponential phase, all strains survived slow freezing at -12 °C for three days, suggesting the possible existence of a cold shock protein yet to be described. At 50 °C, V. cholerae 01 classical and V. cholerae 0139 survived and grew in low numbers, but the 01 El Tor did not survive.

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Persistent Identifier

https://archives.pdx.edu/ds/psu/44502

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