Histochemistry and Ultrastructure of Urocytes in the Pupae of the Stingless BeeMelipona quadrifasciata(Hymenoptera: Meliponini)

Abstract

The main cell types of the adult bee fat body are trophocytes and oenocytes; however, in pupae of some newly emerged bees, trophocytes are modified into cells called urocytes, which possibly function as a substitute for Malpighian tubules during metamorphosis when larval tubules are not functional and/or storage of urate salts is required. This study evaluated the morphology of urocytes in the stingless bee Melipona quadrifasciata and the possibility of maintaining these cells in primary culture. The urocytes M. quadrifasciata are white spherical cells with an irregular surface as observed by stereomicroscopy. They may be found individually or in groups associated with tracheae. Urocytes have a single, small, and spherical nucleus and cytoplasm rich in neutral polysaccharides, lipid droplets, protein, and granules containing calcium and urate salts. Our findings suggest that urocytes play a role in storage of neutral polysaccharides and calcium in M. quadrifasciata pupae and that these cells can be cultured for 72 h.

Demonstrating the general structure and cell types of the fat body in Blatta orientalis (Oriental Cockroach)

“…İzzetoğlu & Gülmez, 2019), the fat body is composed of only trophocytes and oenocytes. In Melipona quadrifasciata, in addition to trophocytes and oenocytes, urocytes are also present (Furtado et al, 2013). The study of Park et al (2013) showed that P. americana possesses trophocytes, urocytes and mycetocytes but no oenocytes in its fat body.…”

“…Hymenoptera) and Lepidoptera, and they take on the role of Malpighi tubules (Arrese & Soulages, 2010;Chapman, 2013;Furtado et al, 2013;Landim & Oliveira, 2006). In P. americana (Dean et al, 1985;Locke, 1984;Park et al, 2013;Wigglesworth, 1987) and B.…”

Maternal control over caste allocation in the ant Cardiocondyla obscurior

“…In insects, urate is typically deposited in specialized cells – so-called urocytes [32] – which together with trophocytes [32] and oenocytes [33] represent the three major cell types in the fat body. Urocytes store urates either in vacuoles or as circular, birefringent spherocrystals [32], and can occupy a large fraction of the fat body, for instance in the termite Mastotermes darwiniensis [32].…”

“…In the termite Reticulitermes flavipes , uric acid is recycled by gut bacteria as a nitrogen source [34], and urate deposits have been linked to oocyte development [35]. In Pachycondyla ants, urocytes specialize in the storage of nutrients and excretion products [36] and a composition assay in Melipona quadrifasciata bees identified Na, Ca, Mg, P as main elements in urocytes, as well as traces of Zn, Mn, and K [33]. In C. obscurior we found circular, birefringent spherocrystals but no cell nuclei, indicating that urate is deposited directly.…”

A high quality method for hemolymph collection from honeybee larvae

“…It is important to point out that sterile samples extractions must be performed in a laminar flow chamber, with the material previously sterilized by ultraviolet light for 25 minutes. Besides, it is recommended that the larvae are disinfected by immersion in 70% alcohol for 1 minute, washing by immersion in autoclaved water for 1 minute (2x) and let them dry on autoclaved filter paper for approximately 2 minutes [52,53], or by raising larvae in vitro in a sterile environment.…”