Fundamental and applied nematology vol:18 issue:3 pages:227-233
Ultrastructural analysis shows the presence of membranes originating at the top of the intestinal microvilli, along the entire length of the intestine in the three rhabditid nematodes Caenorhabditis elegans, Panagrolaimus superbus and Acrobeloides maximus. The membranes allow the passage of fluorescein isothiocyanate, methyl red, neutral red and acridine orange, but allow only sparse passage of ferritin molecules. Upon the introduction of a sublethal dose of sodium azide, the intestinal lumen displays an increased secretion of membrane layers. Whole mount staining of the nematodes with the Solanum tuberosum and Triticum vulgare lectins, known to bind with high affinity to chitin, shows only specific binding of Solanum tuberosum lectin to the brush border in all developmental stages of C. elegans, P. superbus and A. maximus. The results reveal the presence of membranes in the intestine of three species of one of the most ancient metazoan phyla, exhibiting morphological and functional characteristics reminiscent of peritrophic membranes in insects.