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Ultrastructural Studies on the Sporulation of Oocysts of Toxoplasma Gondii
Author(s) -
Ferguson D. J. P.,
BirchAndersen A.,
Siim J. Chr.,
Hutchison W. M.
Publication year - 1979
Publication title -
acta pathologica microbiologica scandinavica section b microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0304-131X
DOI - 10.1111/j.1699-0463.1979.tb02435.x
Subject(s) - rhoptry , organelle , ultrastructure , nucleus , biology , microbiology and biotechnology , vacuole , golgi apparatus , cytoplasm , toxoplasma gondii , microtubule , anatomy , endoplasmic reticulum , apicomplexa , malaria , antibody , immunology , plasmodium falciparum
Sporozoite formation was studied in oocysts which had been allowed to sporulate for 16, 24, 36 and 48 hours at 27° C. The process was initiated within sporocysts which had a fully formed wall. A nucleus was situated at each end of the organism. Two dense plaques which consisted of two closely applied unit membranes with underlying microtubules were observed close to the limiting membrane in the vicinity of each nucleus. At this stage the nuclei possessed an eccentrically located nuclear spindle, the poles of which were directed towards the plaques. Sporozoite formation continued with a posterior growth of the plaques accompanied by an invagination of the limiting membrane. Two sporozoites are formed from each end of the sporocyst. As this is occurring, the Golgi bodies appear active and numerous membranes and vacuoles are formed. Each developing sporozoite encloses a number of these vacuoles (probably precursors of the rhoptries and micronemes) and after the final nuclear division a nucleus is also enclosed. The posterior growth of the plaques continues until the formation of sporozoites is completed. Thus the mature sporocyst contains four sporozoites and a residual cytoplasmic mass. Each sporozoite contains a few polysaccharide granules in addition to the previously mentioned organelles, but lacks refractile or crystalloid bodies.