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The Fine Structure of Differentiating Merozoites of Haemoproteus columbae Kruse *
Author(s) -
BRADBURY PHYLLIS CLARKE,
GALLUCCI BETTY B.
Publication year - 1971
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.1550-7408.1971.tb03397.x
Subject(s) - haemoproteus , plasmodium (life cycle) , rhoptry , biology , leucocytozoon , organelle , gametocyte , cytoplasm , ultrastructure , microbiology and biotechnology , apicomplexa , parasite hosting , anatomy , malaria , immunology , plasmodium falciparum , world wide web , computer science
SYNOPSIS. The first sign of merozoite formation in schizonts of Haemoproteus columbae is the accumulation of dense material at intervals beneath the plasma membrane of the schizont. The schizont's membrane then invaginates in deep furrows cleaving the parasite into pseudo‐cytomeres. thereby increasing the area of membrane available for differentiation. Signs of differentiation appear under this membrane as soon as it is formed. Rhoptries and polar rings develop in the region of the dense accumulations, the cytoplasm containing these structures begins to elevate, and each evagination differentiates into a merozoite. When the merozoite is half‐formed, the cytostome appears, then dense bodies at the apex of the organism, and finally a spherical body intimately associated with a mitochondrion. These merozoites of Haemoproteus are assumed to be the forms that penetrate erythrocytes and become gametocytes. They contain the same organelles as merozoites of Plasmodium. However, the merozoites of Haemoproteus are oval like the erythrocytic merozoites of Plasmodium rather than elongate like the exoerythrocytic merozoites. This body shape may be a generic characteristic or it may indicate a structural difference between exoerythrocytic merozoites and merozoites that infect erythrocytes. When the merozoites of Plasmodium, Haemoproteus and Leucocytozoon are compared, the first 2 genera appear closely related, but Leucocytozoon seems very different. Perhaps it should not be included within the Haemoproteidae.