Absorption of amino acids by Schistosoma mansoni

Abstract

1. 1. The uptake of alanine, arginine, aspartate, glutamate, cycloleucine, leucine, methionine, phenylalanine and valine by Schistosoma mansoni were measured kinetically. The K m (in μmoles) were determined to be 5·56, 3·64, 1·18, 0·14, 4·0, 0·29, 0·29, 0·63 and 0·45 respectively. 2. 2. Except for arginine the above amino acids can be concentrated against a gradient and are thus actively transported. Proline uptake was also examined but apparently it is taken up by simple diffusion. 3. 3. Glutamate and cycloleucine were selected for further study. It was shown that these two amino acids enter Schistosoma via separate sites. The cycloleucine site is shared with leucine, phenylalanine and serine and is sodium insensitive. The glutamate site is shared with aspartate, glutamine and leucine. The site is partly sodium dependent and is inhibited by ouabain and phloridzin.