Reproductive biology, morphology, and morphometry of ovaries and oviducts of Trachemys scripta elegans in Brazilian Cerrado

Gonadal Morphology of Stillborn Hawksbill Sea Turtle (Eretmochelys imbricata) Hatchlings

This study aimed to investigate sexual dimorphism in stillborn hawksbill sea turtles (Eretmochelys imbricata) through gonadal morphological characterizations. Macroscopic, light microscopy, and transmission electron analyses were performed for 30 gonad-mesonephros complexes. Female gonads were spindle-shaped and present a translucent whitish appearance with a grainy texture. Male gonads were approximately ovoid with a smooth opaque white surface. A primary sexual difference concerns different marrow structures, with females presenting organized cellularity featuring oocytes, lacunae, and blood vessels, while males presented a distinct organizational medulla pattern marked by testicular cords extending throughout the gonad length. Ultrastructurally, female's stroma presented interstitial cells and an abundant cytoplasm rich in electrodense droplets and large oval germline cells, with a conspicuous and noncentral nucleus. Males, on the other hand, presented testicular cord cells containing small amounts of heterochromatin and approximately triangular apical and basal cytoplasms with an evident nucleolus characteristic of support cells. Additionally, there were cells with a large spherical nucleus compared with the cell size and a relatively scarce cytoplasm, identified as gonocytes. These findings indicate that macroscopic, microscopic, and ultrastructural evaluations are effective and reliable techniques for the sexual identification of stillborn E. imbricata hatchlings.

Histological study and immunohistochemical location of cytoskeletal proteins in the ovaries of the three species of lizards of the family Leiosauridae (Reptilia: Squamata)

The aim of the study is to expand information on the histological aspect, presence, and distribution of cytoskeletal proteins: smooth muscle alpha-actin (α-SMA), desmin and vimentin in ovaries of three lizards Leiosauridae. In all analysed species, the ovaries were paired organs, located inside the coelomic cavity, covered in a simple cubic epithelium. Below the surface was the tunica albuginea. The organs can be divided into two regions: the cortex and the medulla. The pre-vitellogenic follicles consist of an oocyte surrounded by the pellucid zone periodic acid schiff positive, the granulosa layer consisting of three cell types: small, intermediate, and large and the theca layer. The vitellogenic follicles presented only a single layer of cubic granulosa cells. In the three lizards, α-SMA microfilaments (MFs) were verified along the theca layer and in endothelial cells of the blood vessels of the analysed follicles. Researchers have observed desmin intermediate filaments immunostaining exclusively muscle fibers of the albuginea and the ovarian stroma of Enyalius perditus. There was no immunostaining for vimentin in the ovaries of all the lizards studied. Results obtained revealed that the MFs of α-SMA could be responsible for a contractile activity present in the lizards assessed.