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Vol. 49 No. 1, 2010
Fine Structure of the Midgut Epithelium of Atelura formicaria (Hexapoda: Zygentoma: Ateluridae), with Special Reference to Its Regeneration and Degeneration
Magdalena M. Rost-Roszkowska1,*, Jitka Vilimova2, and Łukasz Chajec1
1Department of Animal Histology and Embryology, University of Silesia, Bankowa 9, 40-007 Katowice, Poland
2Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 128 44 Praha 2, Czech Republic
Magdalena M. Rost-Roszkowska, Jitka Vilimova, and Łukasz Chajec (2010) Atelura formicaria
belongs to a basal hexapod group, the Zygentoma. Its midgut
epithelium is composed of epithelial cells, which are responsible for
digestion, secretion, and absorption, and regenerative cells, which
form regenerative nests. The midgut epithelium ultrastructure was
compared to that described for other zygentoman groups, the
Lepismatidae, and the Archaeognatha, a group closely related to the
Zygentoma. Among regenerative cells, we distinguished midgut stem
cells (resting regenerative cells), which are able to proliferate and
differentiate, and differentiating regenerative cells. Just
before mitotic division in the cytoplasm of stem cells, many cisterns
of endoplasmic reticulum and electrondense granules appear.
During mitosis, the electron-dense granules are still present, but are
not visible in the resting regenerative cells. A morphological
sign of midgut stem cell differentiation is the accumulation of
mitochondria just above the nuclei. They gradually assume
characteristic features of epithelial cells during elongation toward
the midgut lumen. Proliferation and differentiation of
regenerative cells are caused by processes of degeneration (apoptosis
and necrosis), which intensively occur in the midgut epithelium of A. formicaria.
Key words: Midgut epithelium, Differentiation, Regeneration, Degeneration.
*Correspondence: Tel: 48-32-3591376. Fax: 48-32-2596229. E-mail:magdalena.rost-roszkowska@us.edu.pl
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