Morphology and ultrastructure of the adult ovarian cycle in Mithracidae (Crustacea, Decapoda, Brachyura, Majoidea)

Abstract

The ultrastructure of the ovary during development and yolk production is poorly known in Brachyura and Majoidea in particular. Here, we describe the histology, histochemistry and ultrastructure of the adult ovarian cycle in four Mithracidae species from three different genera: Mithrax hispidus, Mithrax tortugae, Mithraculus forceps and Omalacantha bicornuta. All species showed a similar pattern of ovarian development and vitellogenesis. Macroscopically, we detected three stages of ovarian development: rudimentary (RUD), developing (DE) and mature (MAT); however, in histological and ultrastructural analyses, we identified four stages of development. The oocytes of the RUD stage, during endogenous vitellogenesis, have basophilic cytoplasm filled with dilated rough endoplasmic reticulum. The reticulum lumen showed many granular to electron-dense materials among the different stages of development. The Golgi complexes were only observed in the RUD stage and are responsible for releasing vesicles that merge to the endogenous or immature yolk vesicles. At the early DE stage, the oolemma showed many coated and endocytic vesicles at the cortex. The endocytic vesicles merge with the endogenous yolk to form the exogenous or mature yolk vesicles, always surrounded by a membrane, characterizing exogenous vitellogenesis. The exogenous yolk vesicles comprise glycoproteins, showing only neutral polysaccharides. At the late DE stage, endocytosis still occurs, but the amount of endogenous yolk decreases while the exogenous yolk increases. The late DE stage is characterized by the beginning of chorion production among the microvilli. The MAT stage is similar to the late DE, but the endogenous yolk is restricted to a few cytoplasmic areas, the ooplasma is filled with exogenous yolk, and the oolemma has very few coated vesicles. In the MAT stage, the chorion is fully formed and shows two electron-dense layers. The ovarian development of the species studied has many similarities with the very little known Majoidea in terms of the composition, arrangement and increment of the yolk vesicles during oocyte maturation. The main differences are in the vitellogenesis process, where immature yolk formation occurs without the direct participation of the mitochondria but with the participation of the rough endoplasmic reticulum in the endogenous phase.

Scanning electron microscopy of vitellogenic oocytes and spawned eggs of the portunid crab Charybdis hellerii (Crustacea-Brachyura) (Milne Edwards, 1867)

“…The transmission electron microscopy-based findings of Mollemberg et al . [ 38 ] in Mithracidae species from three different genera such as Mithrax hispidus, Mithrax tortugae, Mithraculus forceps, and Omalacantha bicornuta confirm the presence of coated vesicles on the oolemma and many cytoplasmic endocytic vesicles. Such vesicles are responsible for the extracellular uptake of different compounds, a characteristic of the exogenous vitellogenesis.…”

Dry or wet? What is the best choice to determine gonadosomatic and hepatosomatic indexes in females of Macrobrachium amazonicum ?

“…In general, ovaries of decapod crustaceans in early stages of maturation are composed of oogonia and previtellogenic oocytes. These cells have an organelle‐rich cytoplasm responsible for the synthesis of glycoproteins and lipids such as ribosomes, Golgi complexes and rough endoplasmic reticulum (Mollemberg, Zara, & Santana, ; Rotllant, González‐Gurriarán, Fernández, Benhalima, & Ribes, ; Soonklang et al, ). As the ovaries mature further, yolk granules are progressively accumulated in the cytoplasm of the oocytes, significantly reducing the number of cytoplasmic organelles.…”

“…Such granules are formed by the accumulation of vitellogenin (among other precursors), in addition to carotenoid pigments, that is glycolipofosfocarotenoprotein. Together with the lipid droplets, the granules are used as energy reserves and almost completely fill the mature oocytes, significantly reducing their cytoplasmic volume (Braga, Nunes, López‐Greco, Camargo‐Mathias, & Fransozo, ; Mollemberg et al, ; Rotllant et al, ; Soonklang et al, ; Zara et al, ). Haefner and Spaargaren () have shown that the reduction in the amount of water in immature ovaries with values above 70% to 46% in the late stages of development in the brown shrimp Crangon crangon (Linnaeus, 1758) is due to intracellular water depletion in oocytes promoted by the accumulation of energy reserves during vitellogenesis.…”

Reproduction in the spider crab Maiopsis panamensis (Decapoda: Majoidea) in the Gulf of California

“…In other spider crabs, cytological and biochemical changes associated with vitellogenesis have been reported (Arcos-Ortega et al, 2019;Minagawa et al, 1993;Peres-de Souza & Feitosa-Silva, 2009;Ravi et al, 2012). Cell ultrastructure, histology and histochemistry have been described during ovary development and yolk production in other spider crabs including Mithrax hispidus (HERBST 1790), M. tortugae (RATHBUN 1920), Mithraculus forceps (MILNE-EDWARDS 1875), and Omalacantha bicornuta (LATREILLE 1825); all the species have shown a similar pattern of ovarian development and vitellogenesis (Mollemberg et al, 2017). Generally, yolk production in crustaceans consists of endogenous and exogenous synthesis.…”

“…Generally, yolk production in crustaceans consists of endogenous and exogenous synthesis. Endogenous vitellogenesis includes the synthesis and secretion of glycoproteins to form the egg coat surrounding the oocyte by the end of the early vitellogenesis stage (Charniaux-Cotton, 1985;Mollemberg et al, 2017).…”