EFFICIENCY OF AMINO-ACID-TRANSPORT INTO PRESERVED BRUSH-BORDER MEMBRANE-VESICLES FROM LEPIDOPTERAN LARVAL MIDGUT

1. The effect of different conditions of preservation of the larval midgut tissue of Bombyx mori and Philosamia cynthia on the efficiency of amino acid transport into brush border membrane vesicles (BBMV) has been studied, 2. Freezing and storage of the tissue in liquid nitrogen followed by rapid thawing at 37-degrees-C allowed the preparation of BBMV which retained fully for B. mori and partially for P. cynthia the ability to perform L-histidine transport and accumulation. 3. BBMV prepared from fresh midguts of B. mori, immediately frozen and preserved in liquid nitrogen for different periods, lost part of their transport efficiency at the moment of freezing, independently of the time of storage. 4. A decrease was also observed for preserved BBMV from P. cynthia midgut. However, the addition of a cryoprotectant such as glycerol to BBMV improved the performance of the reconstituted preparation. 5. The transport capacity of the stored vesicles depended also on their slow thawing on ice.