Harrop, R., Shah, B., Ashton, P.D. and Wilson, R.A. (2001) The schistosome egg: development and secretions. Parasitology. pp. 329-338. ISSN 0031-1820
We have investigated the development of the schistosome egg and its secretions in order to understand how it migrates through gut tissues and also initiates pathology in the liver. We show by electron microscopy that the subshell envelope is absent in the newly deposited egg, but appears very early and differentiates as development progresses. In the mature egg, this nucleated envelope contains extensive endoplasmic reticulum, suggestive of a protein synthetic capacity. Furthermore, Reynolds' layer only appears between the envelope and the egg-shell in the mature egg and may represent its accumulated secretions. We have biosynthetically labelled and collected the secretions (ESP) released by mature but not immature eggs during culture. Their fractionation by SDS–PAGE reveals a simple pattern of 6 bands, differing markedly in composition from soluble egg antigen preparations. Electrophoresis in casein substrate gels demonstrates the presence of 2 distinct proteases in the egg secretions. By immunocytochemistry, ESP localized predominantly to the envelope of the mature egg, suggesting that this layer rather than the miracidium is the source of egg secretions.
|Copyright, Publisher and Additional Information:||© 2001 by Cambridge University Press. Reproduced in accordance with the publisher's self-archiving policy.|
|Institution:||The University of York|
|Academic Units:||The University of York > Biology (York)|
|Depositing User:||Repository Officer|
|Date Deposited:||06 Sep 2006|
|Last Modified:||04 Sep 2016 00:21|