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Fine Structure of Penetration of Cultured Cells by Isospora canis Sporozoites
Author(s) -
JENSEN JAMES B.,
EDGAR S. ALLEN
Publication year - 1978
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1978.tb04391.x
Subject(s) - rhoptry , cytoplasm , biology , microfilament , vacuole , isospora , pseudopodia , microbiology and biotechnology , penetration (warfare) , anatomy , cytoplast , conoid , biophysics , cell , cytoskeleton , actin , apicomplexa , immunology , biochemistry , operations research , malaria , plasmodium falciparum , feces , engineering
SYNOPSIS Monolayers of Embryonic Bovine Trachea (EBTr) cells were inoculated with Isospora canis Nemeséri spcrozoites. As penetration commenced, they were fixed, stained with OsO 4 ‐ruthenium red, dehydrated, embedded and sectioned in situ. Examination by electron microscopy revealed that host cell membranes remained intact during penetration. The sporozoites caused an invagination of the cell's plasmalemma until the parasites were entirely within the cell, after which the invagination was sealed by short pseudopodia enclosing the parasite within a membrane‐lined vacuole inside the cells. Rhoptries and micronemes, which appeared as branched elements of the same network, became less tortuous near the conoid and often became empty or partially empty during penetration. Concurrent with the appearance of these partially empty rhoptries, vesiculations were seen in the host cell cytoplasm opposite the apical tip of the sporczoite. Constrictions of the sporozoite during entry were probably due to bands of microfilaments beneath the plasmalemma and elsewhere in the cytoplasm of the host cell.