Morphology and function of Malpighian tubules and associated structures in the cockroach, Periplaneta americana

Abstract

This paper describes the different regions of the Malpighian tubules and the associated structures (ampulla, midgut, ileum) in the cockroach, Periplaneta americana. There are about 150 tubules in each insect. Each tubule consists of at least three parts. The short distal region is thinner than the other parts and is highly contractile. The middle region comprises most of the tubule length and is composed of primary and stellate cells. Primary cells contain numerous refractile mineral concretions, while stellate cells have smaller nuclei, fewer organelles, simpler brush border, and numerous multivesicular bodies. Symbiont protozoa are sometimes present within the lumen of the middle region near where it opens into the proximal region of the tubule. The latter is a short region that drains the tubular fluid into one of the six ampullae. These are contractile diverticula of the intestine located at the midgut-hindgut junction. The ampulla is highly contractile, and consists of a layer of epithelial cells surrounding a cavity that opens into the gut via a narrow slit lined by cells of unusual morphology. The proximal region of the tubule and the ampulla resemble the midgut in that they have similar micromal origin and reabsorptive function for the proximal region of the tubule and for the ampulla. A number of inclusions found within the tubule cells are described, including peroxisomes and modified mitochondria. Current theories of fluid transport are evaluated with regard to physiological and morphological characteristics of Malpighian tubules. The possible role of long narrow channels such as those between microvilli and within basal folds is considered, as is the mechanism by which these structures are formed and maintained. Also discussed is the role of peroxisomes and symbionts in the excretory process.

A study of the Malpighian tubules of the plecopteran nymph Paragnetina media (Walker) (Plecoptera: Perlidae) by light, scanning electron, and transmission electron microscopy

“…endoplasmic reticulum as reported in Periplanetu americana 1992). They are mainly composed of calcium, phosphorous, (Wall et al 1975). and magnesium in Musca autumnalis (Grodowitz et al 1987) The vesicular membrane-bound spherites, spherical granand Drosophila hydei ).…”

“…The Malpighian tubules of some insects have distinct histologically recognizable sections (Beams et al 1955;Wigglesworth and Salpeter 1962;Jarial and Scudder 1970;Bradley 1985;Kongoro et al 199 1 ). Other insects have identifiable cell types corresponding to different probable functions interspersed along the length of the tubule (Berridge and Oschman 1969;Sohal 1974;Wall et al 1975;Alkassis and Schoeller-Raccaud 1984;Satmary and Bradley 1984).…”

Ultrastructural analysis of the midgut of Drosophila auraria larvae. Morphological observations and their physiological implications

“…Similar infoldings were found in the midgut (e.g., Waterhouse and Wright 1960;Jones and Zeve 1968;Hecker 1977). the hindgut (Noirot and Noirot-Tinlothee 1976;Bignell 1980), the Malpighian tubules (Sohal 1974;Wall et al 1975). and other visceral tissues of insects.…”

Stellate cells in the Malpighian tubules of Drosophila hydei and D. melanogaster larvae (Insecta, Diptera)

“…In the blowfly Calliphora vicina Robineau-Desvoidy, 1830 (Diptera, Calliphoridae), they preferably take up lead ions and stain darkly (Berridge and Oschman 1969). The small stellate cells are easily seen after selective staining of the nucleus by toluidine blue in Periplaneta americana Linné, 1758 (Orthopteroidea, Blattoidea) (see Wall et al 1975) or crystal violet in Paragnetina media Walker, 1852 (Plecoptera, Pelariae) (see Kapoor 1995). MT of Drosophila hydei Sturtevant, 1921 and Drosophila melanogaster Meigen, 1830 were glued onto coverslips with diluted hen's egg, and hydrolysis was induced with hydrochloric acid, similar to the Feulgen staining technique, in order to stain DNA (Lenz personal communication).…”