Kelley, Cornelia EllefsonThis study was designed to develop an in situ histochemical heme staining method for an intact animal using the free-living nematode Caenorhabditis elegans. Although, heme is vital to many biological processes and synthesized by most known free-living organisms, C. elegans is a natural heme auxotroph. Using the substrate 3-3' diaminobenzidine and hydrogen peroxide, we used C. elegans to study the fate of heme. We found a direct correlation between heme in the growth medium and the organismal heme content. In addition, our studies confirmed that parents exposed to different heme levels contribute varying maternal heme to their progeny. Moreover, this methodology detected differences in heme levels between wild-type and mutants in heme homeostasis. Finally, we provide preliminary evidence that the technique can be applied to analyze heme-based structures at the electron microscopy level. Our studies described herein will aid in the characterization of heme transport pathways in eukaryotes.en-USThesisBiology, Cell