Excretion of nitrogenous substances by Teladorsagia circumcincta was investigated during incubation of L3 in phosphate buffer for up to 30 h and adult worms for 4-6 h. Ammonia was the main excretory product, with about 20% urea. For the first 4-6 h, ammonia excretion by L3 was temperature dependent, directly proportional to the number of larvae, but independent of the pH or strength of the phosphate buffer. Later, ammonia excretion slowed markedly in L3 and adults and reversed to net uptake in L3 by 30 h. An initial external ammonia concentration of 600 μM did not alter the pattern or magnitude of excretion. Re-uptake of ammonia did not occur at extremes of pH or low buffer strength and was slightly reduced at the highest external concentrations. Ammonium transporters and enzymes of glutamate metabolism, including glutamate dehydrogenase, glutamine synthetase and possibly glutamate synthase, are worthy of further investigation as anthelmintic targets. © 2009 Elsevier Inc. All rights reserved.

Item Type:	Refereed Article
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Veterinary Sciences
Research Field:	Veterinary Parasitology
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Livestock Raising
Objective Field:	Sheep - Wool
Author:	Brown, SC (Dr Simon Brown)
ID Code:	61143
Year Published:	2009
Web of Science® Times Cited:	9
Deposited By:	Health Sciences A
Deposited On:	2010-02-26
Last Modified:	2010-10-06
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