Trypanosoma brucei brucei: regulation of ornithine decarboxylase in procyclic forms and trypomastigotes

Experimental Parasitology
C J BacchiP P McCann

Abstract

Ornithine decarboxylase (ODC) activity was measured in procyclic forms of Trypanosoma brucei brucei grown in semidefined medium. ODC activity rapidly increased in late log-phase cells which were resuspended in fresh medium. A biphasic induction curve similar to that observed in mammalian cells was observed over an 18-hr period. ODC activity increased 4.5- to 25-fold over control levels measured at zero time. Actinomycin D and cycloheximide inhibited induction by greater than 90%. Polyamines at a level not inhibitory to growth (10 microM) inhibited ODC induction, but only by 30-50%, late in the induction period. Putrescine inhibited the first peak of induction and suppressed activity at 14 hr by 75%. Polyamine analogs such as bis(ethyl)spermidine were not effective suppressors of ODC activity. The half-life of ODC in procyclic forms grown in the presence of cycloheximide was greater than 6 hr, while that of bloodstream trypomastigotes in mice treated with cycloheximide was 5 hr. A single dose of the ODC inhibitor DL-alpha-difluoromethylornithine given to infected rats or mice suppressed trypanosome ODC activity greater than 90% for more than 7 hr. These studies indicate that although trypanosome ODC increases rapidly under log g...Continue Reading

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Citations

Jul 22, 1992·Biochemical Pharmacology·N YarlettC J Bacchi
Mar 24, 1993·Biochimica Et Biophysica Acta·N YarlettC J Bacchi
Sep 1, 1995·The International Journal of Biochemistry & Cell Biology·R Mukhopadhyay, R Madhubala
Jul 1, 1991·Antimicrobial Agents and Chemotherapy·C J BacchiN Yarlett
Nov 23, 2000·Molecular and Biochemical Parasitology·N Allemann, A Schneider
Oct 12, 2001·International Journal for Parasitology·A Schneider
May 11, 2004·Microbiology·Yekaterina KleydmanThomas E Gorrell
Sep 1, 1990·Transactions of the Royal Society of Tropical Medicine and Hygiene·A H Fairlamb

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African trypanosomiasis, also known as sleeping sickness, is an insect-borne parasitic disease of humans and other animals. It is caused by protozoa of the species Trypanosoma brucei and almost invariably progresses to death unless treated. Discover the latest research on African trypanosomiasis here.