[Mechanisms of determining target locator velocity by dolphins and technical applications in hydrolocation and radiolocation].

Dolphin's (Tursiops truncatus) capacity to discriminate between dynamic characteristics of the object location (the target moving radially) was studied. The dolphin sensitivity thresholds for target velocity (2.6 cm/s) and for target acceleration (0.

[Comparative study of enzymatic activity of cholinesterases of different origin in thionaphthylacetate hydrolysis reactions].

A comparative determination of kinetic parameters V and Km in the reaction of hydrolysis thionaphthylacetate and well known substrate acetylthiocholine by choline esterases from different sources was conducted. It is shown that butyrylcholine esterases hydrolyze thionaphthylacetate with velocity comparable with that of hydrolysis of acetylthiocholine, while acetylcholine esterases and propionylcholine esterases hydrolyze this substrate several times slower than acetylthiocholine. The values of Km in the reactions of hydrolysis of thionaphthylacetate for all studied cholinesterases is an order higher than for acetylthiocholine except cholinesterase of blood serum of fish.

[Use of 1- and 2-thionaphthylacetates as cholinesterase substrates].

1- and 2-thionaphthylacetates were tested as cholinesterase substrates. It was shown that the butyrilcholinesterase from horse serum can hydrolize these compounds. The hydrolysis velocity of 1-thionaphthylacetate was comparable with hydrolysis velocity of acetylthiocholine (the well known cholinesterase substrate), but 2-thionaphthylacetate was hydrolysed more slowly.