ULTRASTRUCTURAL AND LIGHT-MICROSCOPIC LOCALIZATION OF CARBOHYDRATES AND PEROXIDASE CATALASES IN LAGENIDIUM-GIGANTEUM ZOOSPORES

Citation
Ml. Berbee et Jl. Kerwin, ULTRASTRUCTURAL AND LIGHT-MICROSCOPIC LOCALIZATION OF CARBOHYDRATES AND PEROXIDASE CATALASES IN LAGENIDIUM-GIGANTEUM ZOOSPORES, Mycologia, 85(5), 1993, pp. 734-743
Citations number
27
Categorie Soggetti
Mycology
Journal title
ISSN journal
00275514
Volume
85
Issue
5
Year of publication
1993
Pages
734 - 743
Database
ISI
SICI code
0027-5514(1993)85:5<734:UALLOC>2.0.ZU;2-7
Abstract
Zoospores of the oomycete Lagenidium giganteum specifically recognize and then encyst upon mosquito larvae. As a step towards understanding the basis for this specific recognition, we examined the ultrastructur e and cytochemistry of the zoospores. Zoospore shape and organellar ar rangement are similar in L. giganteum and other secondary-type oomycet e zoospores. The ultrastructure of zoospores of L. giganteum differs f rom other Oomycetes mainly in details of vesicle morphology and mitoch ondrial arrangement. In our studies, we emphasized the outer surface o f the zoospores where recognition molecules are likely to be present. Using silver methenamine and thiosemicarbazide-silver proteinate stain sequences, carbohydrate was found at the plasma membrane of zoospores . Ferritin- and fluorescein-labelled concanavalin A binding patterns i ndicated alpha-D-mannosyl and/or alpha-D-glucosyl residues are exposed on the outer surface of the plasma membrane of the zoospore and the w all of the cyst. Within the zoospores, the membranes of small peripher al vesicles, and the membranes and contents of golgi apparati and peri pheral cisternae showed evidence of carbohydrate content with silver s taining. We did not find clear evidence of carbohydrates among the con tents of the large and small peripheral vesicles. Zoospores treated wi th diaminobenzidine to visualize peroxidases and catalases exhibited i ncreased light and electron opacity in their mitochondria, as well as a fuzzy coat on the external surfaces of their plasma membranes.