ISSN:
1432-1955
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Electron microscope observations of the “excretory” cell of the infective larva reveal that it contains a large nucleus surrounded by cytoplasm containing numerous organelles, multi-granular bodies, vesicles and granules typical of glandular cells. The proximal region of the “excretory” duct bears a number of scattered microvilli, on its adluminal surface, and the distal region is lined with a thin multilayered cuticle. In the liver stage larva 2 days after infection, 2 lateral “excretory” columns are present. These arise from the “excretory” cell body and extend posteriorly for about half the length of the intestine. Each column contains a narrow longitudinal canal surrounded by cytoplasm rich in mitochondria, granular endoplasmic reticulum, free ribosomes and large vacuoles. Evidence was obtained of the passage of substances through the wall of the canal but their chemical nature was not determined. Further extension of the lateral columns is seen in the 8-day, lung-stage larva, the columns now extending for more than two-thirds the length of the intestine. Their diameter is also increased but their internal structure is essentially similar to that of the 2-day liver-stage larva. The “excretory” duct which arises immediately anterior to the nucleus has a structure similar to that of the lateral columns for the first half of its length, the microvilli described in the infective larva being absent at this stage. The distal half of the duct is lined with cuticle.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00348558
