Effects of oxygen availability on metabolic enzyme abundances in Leptomonas pyrrhocoris

Abstract

Trypanosomes are parasitic protozoans. Trypanosomes have a unique membrane-bound metabolic organelle called the glycosome, which contains the first seven steps of glycolysis. It is thought the glycosome formed to facilitate enzymatic overhauls that were cellular responses to altered environmental conditions. Environmental changes are more apparent for dual-host trypanosomes, but the glycosome is still found in single-host species. This led to the research question: In single-host trypanosomes, what environmental condition could potentially cause glycosomal protein abundance changes? We hypothesized that a dramatic change in oxygen levels is responsible for the overhaul of glycosomal enzymes in the single-host trypanosome species Leptomonas pyrrhocoris. Additionally, this overhaul would not be seen in metabolic enzymes located outside the glycosome. To test the hypothesis, Leptomonas pyrrhocoris cells were placed in hypoxia and normoxia conditions. Cell counting and protein collection occurred on days two, three, and six. The abundances of five glycosomal enzymes and one cytoplasmic enzyme were measured via western blotting. Significance was determined through an unpaired two-tailed t-test. Trends observed in all enzymes showed that by day three enzymatic abundance was greater in hypoxia. This trend was either maintained or amplified through day six in all but one enzyme. However, because this trend was also observed in the cytosolic enzyme, the hypothesis was rejected. The trend seen in all enzymes suggests that while a change in oxygen level does cause an enzymatic overhaul, it is not one related to the glycosome.