(1992). Taxonomy of Phylum Microspora. Critical Reviews in Microbiology: Vol. 18, No. 5-6, pp. 285-395.

Taxonomy of phylum microspora

Leishmania donovani, the etiological agent of human visceral leishmaniasis, was grown in hamster peritoneal macrophages in vitro. By electron microscopy, using a lysosomal marker, these parasitic protozoa were seen to multiply within host cell phagolysosomes. The survival mechanism of this intracellular parasite is based apparently upon resistance to macrophage lysosomal enzymic digestion.

https://science.sciencemag.org/content/sci/193/4254/678.full.pdf

Multiplication of a human parasite (Leishmania donovani) in phagolysosomes of hamster macrophages in vitro

Considerable knowledge of microsporidian structure has been accumulated during 150 years of research. Critical evaluation of this knowledge reveals, however, that most progress has been achieved during the past fifteen years after electron microscopic application. Although some light microscope observations have contributed amazingly accurate data on microsporidian structure, the extreme smallness of microsporidia (the spores of which are probably the smallest eukaryotic cells) as well as the compactness and complexity of their structural organization requires better resolution than that obtained with the light microscope.

Structure of the Microsporidia

This synopsis reviews taxonomy, morphology, distribution, life history, commercial hard and soft shell crab fisheries, physiology, diseases, ecology, laboratory culture methodology, and influences of environmental
pollutants on the blue crab, Callinecles sapidus. Over 300 selected, published reports up to and including 1982
are covered. (PDF file contains 45 pages.)

/pdf/synopsis-of-biological-data-on-the-blue-crab-callinectes-3ean3wkj6r.pdf

Synopsis of biological data on the blue crab, callinectes sapidus Rathbun

This chapter reviews the morphological features and development of the microsporidia. The general life cycle pattern of the microsporidia can be divided into three phases: the infective or environmental phase, the proliferative phase, and the sporogony or spore forming phase. The chapter discusses the host-parasite interface during parasite development. Microsporidia with host-produced interfacial envelopes are those that are separated from the hyaloplasm by host-produced membranes during proliferation through spore formation. Microsporidia having indirect contact between host- and parasite-produced interfacial envelopes are separated from the hyaloplasm by membranes and/or secretions produced by both the host and the parasite. The proliferative phase has been referred to as schizogonic and merogonic by some authors, however, different authors have assigned different types of nuclear activity to the terms merogony and schizogony with respect to the microsporidia. Recognizing the diversity of polaroplast morphology and organization in various species of microsporidia, Larsson described five types of polaroplast structural arrangements. In addition to environmental spores, some microsporidia produce autoinfective spores which become activated and germinate within the same host in which they were just produced. A few microsporidia of the genus Amblyospora have two host cycles with morphologically different spores in each and different development in the males and females of the same host species.

Developmental Morphology and Life Cycles of the Microsporidia

Vegetative growth of Nosema sp. occurs within the gut submucosal cells of Callinectes sapidus. Vegetative cell morphology is dominated by profiles of endoplasmic reticulum, numerous free ribosomes and aggregates of vesicles enclosed by a membranous sac. The dikaryotic vegetative cell is the earliest stage found in the target area for sporogenesis, the sarcoplasm of the striated muscle cell. The next obvious stage is the sporoblast mother cell; it undergoes karyokinesis without breakdown of the nuclear envelope. Intranuclear mitotic microtubules extend from the chromosomes to the intact nuclear envelope. After repeated nuclear divisions, the sporoblast mother cell undergoes delayed cytokinesis and a series of sporoblast progeny develops.

Earl Weidner

Papers

Ultrastructural study of microsporidian development. I. Nosema sp. Sprague, 1965 in Callinectes sapidus Rathbun.