Meeting Abstract
Bamboo lemurs (Prolemur simus and Hapalemur ssp.) survive eating typically deadly concentrations of cyanide in their natural diet of bamboo. This trait is an evolutionary novelty, making bamboo lemurs the only mammals known to survive such high cyanide concentrations. How they do so has remained a mystery for nearly 30 years. To understand the nature of this adaptation we must understand the biochemical and metabolic processes at work, but the Critically Endangered status of these species limits options for study. We used a novel approach: cyanide is excreted in unknown form in the urine of these species. The form of cyanide excreted (cyanide ion or a detoxification product) is informative of the biochemical or metabolic process allowing these species to survive. To determine the chemical structure of excreted cyanide, we collected urine samples from wild (N = 46) and captive (N = 7) bamboo lemurs (P. simus, H. aureus, and H. griseus) from Madagascar and comparative samples from closely related non-bamboo eating (thus non-cyanide consuming) lemurs at the Duke Lemur Center. We then adapted gas chromatography-mass spectrometry (GCMS) analytical methods to test for cyanide (CN–), thiocyanate (SCN–, the primary mammalian cyanide detoxification product), and the cyanide metabolite ATCA (2-aminothiazoline-4-carboxylic acid) in lemur urine. Comparing cyanide consuming and non-consuming species allows inference of the biochemical and metabolic processes acting on consumed cyanide. The preliminary results of these chemical analyses provide the first evidence for the biochemical mechanisms behind this extreme dietary adaptation.
