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Disrupting Monoallelic Expression Of Variant Surface Glycoprotein In Trypanosoma Brucei By A Non-Lethal Mutation In Class I Transcription Factor A, Sarah Platt May 2022

Disrupting Monoallelic Expression Of Variant Surface Glycoprotein In Trypanosoma Brucei By A Non-Lethal Mutation In Class I Transcription Factor A, Sarah Platt

Honors Scholar Theses

Human African trypanosomiasis (HAT) is a lethal disease caused by protozoan hemoflagellates of the genus Trypanosoma. Humans are vulnerable to two subspecies, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. At the crux of HAT lethality lie two uncommon genetic expression phenomena: monoallelic expression and antigenic variation. Combined, these mechanisms effectively shield trypanosomes from host immune systems, prolonging infections. Variant Surface Glycoproteins (VSGs) are the key outer membrane proteins involved in antigenic variation. By continuously changing the composition of cell surface antigens, trypanosomes can survive bouts of immunological detection and eventually traverse the blood-brain barrier. There are over two …


Regulation Of Antigenic Variation By Trypanosoma Brucei Telomere Proteins Depends On Their Unique Dna Binding Activities, Bibo Li Ph.D., Yanxiang Zhao Aug 2021

Regulation Of Antigenic Variation By Trypanosoma Brucei Telomere Proteins Depends On Their Unique Dna Binding Activities, Bibo Li Ph.D., Yanxiang Zhao

Biological, Geological, and Environmental Faculty Publications

Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, Variant Surface Glycoprotein (VSG), to evade the host immune response. Such antigenic variation is a key pathogenesis mechanism that enables T. brucei to establish long-term infections. VSG is expressed exclusively from subtelomere loci in a strictly monoallelic manner, and DNA recombination is an important VSG switching pathway. The integrity of telomere and subtelomere structure, maintained by multiple telomere proteins, is essential for T. brucei viability and for regulating the monoallelic VSG expression and VSG switching. Here we will focus on T. brucei TRF and RAP1, two telomere …


Keeping Balance Between Genetic Stability And Plasticity At The Telomere And Subtelomere Of Trypanosoma Brucei, Bibo Li Ph.D. Jul 2021

Keeping Balance Between Genetic Stability And Plasticity At The Telomere And Subtelomere Of Trypanosoma Brucei, Bibo Li Ph.D.

Biological, Geological, and Environmental Faculty Publications

Telomeres, the nucleoprotein complexes at chromosome ends, are well-known for their essential roles in genome integrity and chromosome stability. Yet, telomeres and subtelomeres are frequently less stable than chromosome internal regions. Many subtelomeric genes are important for responding to environmental cues, and subtelomeric instability can facilitate organismal adaptation to extracellular changes, which is a common theme in a number of microbial pathogens. In this review, I will focus on the delicate and important balance between stability and plasticity at telomeres and subtelomeres of a kinetoplastid parasite, Trypanosoma brucei, which causes human African trypanosomiasis and undergoes antigenic variation to evade the …


Hematological And Clinical Studies In West African Dwarf Sheepexperimentally Infected With Trypanosoma Brucei And Treated Withdiminazene Aceturate, Levamisole, And Vitamin A, Clara Akpan, Nwakaego Nweze, Cornelius Chukwu Jan 2018

Hematological And Clinical Studies In West African Dwarf Sheepexperimentally Infected With Trypanosoma Brucei And Treated Withdiminazene Aceturate, Levamisole, And Vitamin A, Clara Akpan, Nwakaego Nweze, Cornelius Chukwu

Turkish Journal of Veterinary & Animal Sciences

The effects of diminazene aceturate (DA), levamisole, and/or vitamin A on hematological and clinical parameters of West African dwarf sheep experimentally infected with Trypanosoma brucei were studied. Twenty-four adult sheep were randomly assigned to 6 groups of 4 animals. They were infected with 1 × 10$^{6}$ trypanosomes intravenously (groups 2?6) or were uninfected (group 1). Treatment was administered 2 weeks post infection (PI) in all treated groups, except group 5, which was treated 3 weeks PI. Group 2 (positive control) received 7 mg/kg DA. Group 3 received 7 mg DA and 5 mg levamisole per kilogram of body weight. Group …