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Histochemical glycogen and neutral lipid in Echinostoma trivolvis cercariae and effects of exogenous glucose on cercarial longevity

Published online by Cambridge University Press:  05 June 2009

B. Fried*
Affiliation:
Department of Biology, Lafayette College, Easton, Pennsylvania 18042, USA.
L.S. Eyster
Affiliation:
Science Department, Milton Academy, Milton, Massachusetts 02186, USA.
J.A. Pechenik
Affiliation:
Biology Department, Tufts University, Medford, Massachusetts 02155, USA
*
*Fax: 610 250 6557 E-mail: [email protected]

Abstract

Histochemical glycogen and neutral lipid studies were conducted on Echinostorna trivolvis cercariae maintained in artificial spring water (ASW) at 24–25°C for up to 24 h after emergence from host snails. Treatment of whole cercariae by the periodic acid Schiff (PAS) reagent with or without 1% malt diastase showed that cercariae depleted glycogen mainly from the tail by 6 to 24 h postemergence. The posterior tip of the tail remained PAS positive and diastase fast suggesting the presence of mucopolysaccharides there. Fresh cercariae or those stained up to 24 h postemergence with Oil Red 0 showed the presence of neutral lipid droplets in the excretory system. There was no discernible difference in the size, abundance, or distribution of these droplets in fresh or aged cercariae. Cercariae maintained in ASW plus 1% glucose for 12 or 23 h showed no evidence of resynthesizing glycogen. Nevertheless, cercariae survived longer in 1% glucose than in either 0.0, 0.1 or 0.5% glucose; but only at 23 h were any differences statistically greater (one way ANOVA, P <0.05).

Type
Research Note
Copyright
Copyright © Cambridge University Press 1998

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