Abstract

Trypanosoma lewisi is an arthropod-transmitted protozoan parasite found in the bloodstream of rats. In its life cycle it undergoes cellular differentiation. It is primarily found as the trypomastigote form in the rat and as the epimastigote form in the arthropod, the rat flea. Various studies have been done on hemoflagellates to determine the factors responsible for stimulating the differentiation from one form to the other. Included in these factors are pH, temperature, and protein fractions from fetal calf serum. Recent efforts have also been aimed at developing simple or defined media for physiological or biochemical studies on hemoflagellates. The purpose of this work was to establish a differentiation pattern for T. lewisi in the defined medium RE I and to determine an optimum temperature and pH for stimulating differentiation from the trypomastigote form to the epimastigote form. T. lewisi can be maintained in vitro for 22 days and will differentiate in RE I. The results of the temperature and pH studies were not definitive for one optimum temperature or pH. At 35°C there seems to be a decrease in the viability of all forms. In all runs a lag time is observed at 30°C before differentiation occurs. The greatest differentiation occurred at 20°C and 25°C. Further work may indicate which of these two temperatures is optimum for differentiation. At pH 6.0, for all four temperatures, the viability of all forms was poor and low percentages of epimastigotes were found. The highest percentages of epimastigotes were found at the pH values of 7.0 and 7.3 for all temperatures. From the data presented it is difficult to determine which of these two pH values is more significant in stimulating differentiation. Additional results were obtained which indicate several other factors may contribute to the rate of differentiation. A higher percentage of epimastigotes was found when culturing unwashed trypanosomes than when culturing washed cells. Greater differentiation occurred in the cultures with a larger initial inoculum. These results suggest that the initial cell concentration and/or some serum factor(s) may influence the differentiation rate of T. lewisi.

LLU Discipline

Microbiology

Department

Microbiology

School

Graduate School

First Advisor

Edward D. Wagner

Second Advisor

Charles E. Winter

Third Advisor

Robert W. Teel

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1979

Date (Title Page)

6-1979

Language

English

Library of Congress/MESH Subject Headings

Trypanosoma lewisi; Cell Differentiation

Type

Thesis

Page Count

vii; 58

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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