Cellulase activity of Leishmania major in the sandfly vector and in culture

The secretion of cellulose-degrading enzymes by Leishmania promastigotes in culture and in the sandfly vector was demonstrated. Two types of activity of cellulase enzyme-complexes were measured: endoglucanases, which randomly cleave cellulose chains and cellobioydrolases, which remove cellobiose from the nonreducing end of the molecule. The assays demonstrated that enzymes with these activities were secreted into the culture medium by Leishmania major, L. donovani, and L. braziliensis. These activities were also found in cultures of Sauroleishmania agamae, Leptomonas seymouri, Herpetomonas muscarum, Crithidia fasciculata and Trypanosoma brucei brucei that had a relatively low endoglucanase activity. Both endoglucanase and cellobiohydrolase activities were found in the gut of L. major-infected Phlebotomus papatasi, while gut preparations of uninfected sandflies had only cellobiohydrolase activity. The similar growth of L. major parasites in medium supplemented with either cellulose or glucose suggests these parasites can utilize cellulose.