Structure of the midgut epithelium in four diplopod species: histology, histochemistry and ultrastructure

Abstract

The middle region of the digestive system of millipedes, the midgut, is responsible for all processes connected with digestion, but also takes part in homeostasis maintenance thanks to the ability to activate many mechanisms which neutralize changes occurring at different levels of the animal’s body. Numerous millipede species are treated as bioindicators of the natural environment and they are exposed to different stressors which originate from external environment. To obtain all data on the functioning of midgut of millipedes as the barrier against stressors, it is necessary to have a precise and general description of the midgut epithelium. Members from four millipede orders were selected for the studies: Polydesmus angustus (Polydesmida), Epibolus pulchripes (Spirobolida), Unciger transsilvanicus (Julida) and Glomeris tetrasticha (Glomerida). The structure and ultrastructure of their midgut epithelial cells (the digestive, secretory and regenerative cells) were documented using transmission electron microscopy and histochemical methods. The obtained results have been compared and discussed to previous ones, to present the general and structural organization of the midgut in Diplopoda. Our studies revealed that the ultrastructure of all cells which form the midgut epithelium in millipedes is general for all the species studied up to now and it resembles the cell ultrastructure observed in Chilopoda and Hexapoda, including the digestive, secretory and stem cells.

Novel Aryl Thioamides Derivatives as Insect Growth Regulators Analogues against Spodoptera littoralis (Lepidoptera: Noctuidae): Design, Synthesis, Insecticidal Activity and Biochemical Impacts

“…Columnar cells for enzyme absorption and secretion by apical surface with long regular microvilli, goblet cells for ionic homeostasis, endocrine cells for endocrine function, and regenerative cells for epithelium renewal by repairing and replenishing the worn‐out midgut epithelium that is lost during the digestive process [33,34] . They can be seen alone or in clusters close to the base of the midgut [35,36] . Numerous studies have shown that physiological alterations, such as variations in food absorption and digestion in the alimentary canal, can affect an insect‘s growth and development (Figure 9).…”

“…[33,34] They can be seen alone or in clusters close to the base of the midgut. [35,36] Numerous studies have shown that physiological alterations, such as variations in food absorption and digestion in the alimentary canal, can affect an insect's growth and development (Figure 9). [37,38] As regarding, the treated larvae with 11 displayed severe deformation, obvious necrosis, columnar cell shortening, and significant apical region degeneration because apocrine secretion largely damaged the apices of epithelial cells, as illustrated in Figure 10.…”

Effect of gluten on the digestive tract and fat body of Telodeinopus aoutii (Diplopoda)

“…Mitochondria are also responsible for the activation of numerous proteins or enzymes involved in the processes of survival or death (Bratic & Larsson, 2013; Faron et al, 2015; Hödl et al, 2010; Kühlbrandt, 2015; Rost‐Roszkowska, Poprawa, et al, 2021; Włodarczyk et al, 2017). All changes in their structure, membrane potential, or metabolism are related to degenerative processes (Bednarska & Świątek, 2016; Faron et al, 2015; Hödl et al, 2010; Nunnari & Suomalainen, 2012; Rost‐Roszkowska, Vilimová, et al, 2021; Włodarczyk et al, 2017; Xia et al, 2019). We observed changes in digestive cells' ultrastructure and the cell death processes according to prolonged gluten consumption.…”