In vivo effects of putative crowding factors on Hymenolepis diminuta

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Title: In vivo effects of putative crowding factors on Hymenolepis diminuta
Author: Cook, Ronald Lynn
Abstract: During in vitro incubation , Hymenolepis diminuta secretes substances into the medium that inhibit DNA synthesis in the germinative region of freshly isolated , uncrowded worms . Of the many substances that are released by H . diminuta into the medium , only succinate , acetate , glucosaminic acid and cGMP are apparendy responsible for the inhibition (Zavras and Roberts , 1985 ) . These substances were referted to as "putative crowding factors" by Zavras and Roberts (1985 ) . The effects of these crowding factors on worm development in \ivo were examined . At seven days post infection the proximal end of the hosts' intestine was catheterized and perfused with test solution . In some experiments 4 .3 M succinate , 5 .0 M acetate , or both were perfused by an Alzet® osmotic pump . In other experiments a solution containing 28 nM cGMP , 250 |LiM glucosaminic acid , 120 mM succinate , and 40 mM acetate was perfused by a peristaltic pump at a rate of 50 ml /day . At 2 weeks post infection , the worms were recovered for subsequent analysis . The test solutions in the osmotic pumps did not affect the wet weights of the worms . In the experiments using a peristaltic pump , worms exposed to the crowding factors were 53 % less in wet weight than the control worms . Carbohydrate concentrations in worms from experimental groups were not different from those in control groups ; therefore , the inhibition in growth was probably not due to carbohydrate deprivation . Worms from experimental groups had fewer immature , mature , and gravid proglottids than did worms from control groups . Attempts to measure succinate levels in the tat intestine were unsuccessful .
URI: http : / /hdl .handle .net /2346 /18358
Date: 1989-05

Citation

In vivo effects of putative crowding factors on Hymenolepis diminuta. Master's thesis, Texas Tech University. Available electronically from http : / /hdl .handle .net /2346 /18358 .

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