- Individual acid aspartic proteinases (Saps) 1-6 of Candida albicans are not essential for invasion and colonization of the gastrointestinal tract in mice. Kretschmar, M., Felk, A., Staib, P., Schaller, M., Hess, D., Callapina, M., Morschhäuser, J., Schäfer, W., Korting, H.C., Hof, H., Hube, B., Nichterlein, T. Microb. Pathog. (2002)