CHEMORECEPTION IN THE SHRIMP, PALAEMONETES PUGIO: COMPARATIVE STUDY OF STIMULATORY SUBSTANCES IN HUMAN SERUM

Abstract

1. A bioassay procedure is described for studying a chemically mediated feeding response in the shrimp, Palaemonetes pugio. The procedure involves the attraction of shrimp to a small target in compartmented plastic boxes.2. Bioassays of purified components of human serum showed that the response of shrimp to serum is due to a mixture of substances including both proteins and substances of low molecular weight.3. A dialyzed mixture containing six types of serum proteins accounted for approximately one-fourth of the potency of serum. Although all of the proteins possessed a certain degree of activity, low density lipoprotein and the alphaglobulins were individually the most active components of the mixture.4. A mixture containing the 37 major low molecular weight organic constituents of serum accounted for only approximately one-eighth of the potency of serum. Glycine, taurine and glutamic acid were the most active constituents of this mixture that were tested individually.5. A mixture containing the six types of serum proteins together with the 37 low molecular weight constituents was fully as active as the total serum.6. Ultrafiltration of body fluids or extracts from coquina, crab, lobster, oyster and shrimp showed that in some preparations the major stimulants were large molecules (greater than ca. 1000 MW) whereas in others they were small molecules.