Horseradish
Biomedical uses

The enzyme horseradish peroxidase (HRP), found in the plant, is used extensively in molecular biology and biochemistry primarily for its ability to amplify a weak signal and increase detectability of a target molecule. HRP has been used in decades of research to visualize under microscopy and assess non-quantitatively the permeability of capillaries, particularly those of the brain.
startend:quotation, oulipo:avoid_letter[o]