IV. 



Occurrence of Antiproteases in the Larvae of the Sarcophaga 



Associates of Sarracenia flava 



By 



Joseph Samuel Hepburn and Frank Morton Jones 



The parasitic intestinal worms of man and the domestic animals con- 

 tain antiproteases (antipepsin and antitrypsin), which effectively pre- 

 vent the digestion of the parasite by the proteolytic enzymes in the 

 digestive fluids of the host. This is especially true of A scar is (1). 



The pitcher liquor of Sarracenia flava contains a proteolytic enzjTne 

 (2). The larvae of certain species of Sarcophaga {sarraceniae Riley, 

 Rileyi Aldrich, and Jonesi Aldrich) habitually occur in the pitchers of 

 Sarracenia flava, where they are constantly bathed in the digestive 

 liouor of the pitcher. This phenomenon suggested the examination of 

 Sarcophaga larvae from Sarracenia pitchers for the presence of anti- 

 proteases. Live larvae obtained from open pitchers of Sarracenia flava 

 were used in the study. Two series of experiments were made. 



In the first series, 16 larvae (total weight L86 grams) were crushed, 

 and ground with sand and 4.5 cc. of distilled water. The turbid solution 

 and suspended ti?sue were removed by decantation, and were mixed 

 with sufficient 95 percent alcohol to render the final concentration of 

 the alcohol 60 percent. The precipitate which formed was collected 

 on a filter and dried over calcium chloride in a dessicator. The filtrate 

 was mixed with alcohol until the concentration of the latter was 85 

 percent; the precipitate which formed was negligible, although the 

 antiproteases should have separated at this point. 



The thought, that possibly the rather tough larval tissue had not 

 been ground sufficiently to liberate the antiproteases, led to an examina- 

 tion of the first precipitate for these antienz>Tnes. When thoroughly 

 dry, the precipitate was separated from the filter paper, ground inti- 

 macely with glass powder, and then triturated with 10 cc. of distilled 

 water. A supernatant liquid was obtained by centrifugation; 2.5 cc. 

 of this liquid and 2.5 cc. of a 1 percent solution of pepsin in 50 percent 

 glycerol were mixed; and sufficient hydrochloric acid and trikresol were 

 added to produce a concentration of 0.2 percent of each of these reagents. 

 The resulting solution was allowed to stand for 2 hours at room tempera- 

 ture to permit the pepsin and the antipepsin (if present) to combine. A 



