Anatomo-histological evaluation of male reproductive system of the juvenile Caiman crocodilus yacare / Evaluación anátomo-histológica del sistema reproductor del Caiman crocodilus yacare macho juvenil

SUMMARY: The Caiman crocodilus yacare was once close to extinction. Studies about the male reproductive tract may aid in their reproduction and conservation. In this work, after sedation and euthanasia, seven young male C. yacare were submitted to necropsy, and macroscopic evaluation of the reproductive system, while the three others were admitted for histological study. The histological sections were stained with Hematoxylin & Eosin and Masson's Trichrome. After opening the pleuroperitoneal cavity it was possible to identify that the testicles were disposed in pairs and attached to its dorsal surface. The epididymis showed elongated and convoluted shapes and were located at the cranial margin of the testicles, following its medial portion, which was the same portion that the "vas deferens" stems from until the opening of the cloaca. The crocodile phallus presented a tubular shape, with conical appearance, displaying little resistance while maintaining its flexibility, compatible with a fibrocartilaginous tissue. On light microscopic analysis it was possible to observe that the testis was delimited by the tunica albuginea. The seminiferous tubules were contorted, and the interstitial space was filled with interstitial tissue and Leydig cells. The epididymal ductus were covered with non-ciliated pseudostratified epithelium with cells varying between cuboidal and prismatic shapes. The ductus deferens were characterized by a narrow girth shrouded with non- ciliated pseudostratified prismatic epithelium. The phallus of the crocodile was covered with a non-keratinized squamous epithelium surrounded by connective tissue. The findings support anatomic and histologic knowledge Alligatoridae reproductive system, enabling further research in the C. yacare reproduction and conservation.

RESUMEN: El Caiman crocodilus yacare ha estado en peligro de extinción. Los estudios sobre el aparato reproductor del macho pueden ser de ayuda en su reproducción y conservación. En este trabajo, fueron sometidos a necropsia y evaluación macroscópica del aparato reproductor, siete machos jóvenes de C. yacare, mientras que otros tres fueron utilizados para su estudio histológico. Las secciones histológicas se tiñeron con hematoxilina y eosina y tricrómico de Masson. Después de examinar la cavidad pleuroperitoneal se pudo identificar que los testículos estaban dispuestos en pares y adheridos a su superficie dorsal. El epidídimo presentaba formas alargadas y contorneadas y se ubicaba en el margen craneal de los testículos, siguiendo su porción medial, que era la misma porción de donde parten los conductos deferentes hasta la apertura de la cloaca. El pene del cocodrilo presentaba forma tubular, de apariencia cónica, mostrando poca resistencia manteniendo su flexibilidad, compatible con un tejido fibrocartilaginoso. En el análisis microscópico óptico se pudo observar que el testículo estaba delimitado por la túnica albugínea. Los túbulos seminíferos estaban contorsionados y el espacio intersticial estaba lleno de tejido intersticial y células intersticiales (células de Leydig). El epidídimo estaba cubierto con epitelio pseudoestratificado no ciliado con células que variaban entre formas cuboideas y prismáticas. Los conductos deferentes se caracterizaron por una circunferencia estrecha envuelta en un epitelio prismático pseudoestratificado no ciliado. El pene del cocodrilo estaba cubierto con un epitelio escamoso no queratinizado rodeado de tejido conectivo. Los hallazgos corroboran el conocimiento de la anatomía del sistema reproductivo de Alligatoridae, lo que permite una mayor investigación sobre la reproducción y conservación de C. yacare.

Aedes aegypti: egg morphology and embryonic development.

BACKGROUND: The diseases for which Aedes aegypti is a vector are worrisome. The high vector competence of this mosquito, as well as its anthropophilia and ability to adapt to the urban environment, allows it to exploit many habitats, making its prevention an arduous task. Despite current disease control measures focused on the mosquito, the effectiveness in containing its dispersion still requires improvement; thus greater knowledge about this insect is fundamental. METHODS: Aedes aegypti egg morphology and embryonic development were analyzed from eggs of the insectary of the Institute of Biomedical Sciences of the University of São Paulo. Optical (light and confocal) and electronic (transmission and scanning) microscopy were used to analyze the morphological and ultrastructural features of the eggs. Embryos were observed in the initial (0-20.5 h after egg-laying), intermediate (20.6-40.1 h after egg-laying), and final (40.2-61.6 h) stages of development, and kept at a temperature of 28 °C ± 1 °C until collection for processing. RESULTS: Eggs of Ae. aegypti were whitish at the time of oviposition, and then quickly became black. The egg length was 581.45 ± 39.73 µm and the width was 175.36 ± 11.59. Access to the embryo was difficult due to the egg morphology, point of embryonic development, and difficult permeability of the exochorion (mainly in fixation). Only about 5% of the collected eggs were successfully processed. In the initial stage of embryonic development, characteristics suggestive of intense cellular activity were found. In the intermediate stage, the beginning of the segmentation process was evident. In the final phase, it was possible to differentiate the cephalic region and the thoracic and abdominal segments. CONCLUSION: The chorion was found to be an important protective barrier and a limiting factor for the evaluation of the embryos and mosquito embryonic cells, indicating that further studies need to be carried out to identify the reason that this occurs.

Determination of the relationship among cell proliferation, metabolic activity and stage of pregnancy by AgNORs as markers in bovine placenta / Determinación de la relación entre la proliferación celular, la actividad metabólica y la etapa de preñez por los AgNOR como marcadores en la placenta bovina

SUMMARY: Nucleolus Organizer Regions (NORs) are defined as nucleolar components containing argyrophilic proteins selectively stained by silver methods (AgNORs). Several investigations have shown the AgNOR quantity and area represent a valuable parameter of cell kinetics, since they reflect the level of activity and cellular proliferation. This article addresses an evaluation of the functional activity and relation between days of pregnancy and proliferative capacity of trophoblastic mononucleate and binucleate cells from bovine placentomes. Both the number and size of AgNORs were determined in different phases of gestation by silver nitrate staining in conventional histological slides. The results showed a significant increase (from 1 to 12 AgNORs) in the number of AgNORS per trophoblastic mononucleate cell in the 3rd trimester, with predominance of 4-6 AgNORs/cell. In the 1st and 2nd trimesters, the number ranged between 1 and 9 AgNORs/cell, with predominance of 1-3 AgNORs. No significant differences were observed between the 2nd and 3rd trimesters, but in the first, in binucleate cells (19-27 and 10-18 AgNORs/cell, respectively) - this number was higher than the one registered in trophoblastic mononucleate cells in the same period. Thus, AgNORs can be used as markers of the proliferative placental cell cycle and established a relation between number of AgNORs and days of gestation. This relation can be used for diagnoses and prognoses of several placental pathologies, including pregnancy losses from manipulated embryos.

RESUMEN: Las Regiones Organizadoras de Nucléolos (NOR) se definen como componentes nucleolares que contienen proteínas argirofílicas teñidas selectivamente por métodos de plata (AgNOR). Varias investigaciones han demostrado que la cantidad y el área de AgNOR representan un parámetro importante de la cinética celular, ya que reflejan el nivel de actividad y proliferación celular. Este trabajo analiza la actividad funcional y la relación entre los días de preñez y la capacidad proliferativa de las células trofoblásticas mononucleadas y binucleadas de placentomas bovinos. Tanto el número como el tamaño de los AgNOR se determinaron en diferentes fases de la gestación mediante tinción con nitrato de plata en portaobjetos histológicos convencionales. Los resultados mostraron un aumento significativo (de 1 a 12 AgNOR) en el número de AgNORS por célula mononucleada trofoblástica en el tercer trimestre, con predominio de 4-6 AgNOR / célula. En el primer y segundo trimestre, el número osciló entre 1 y 9 AgNOR / célula, con predominio de 1-3 AgNOR. No se observaron diferencias significativas entre el 2do y 3er trimester; en el primer trimestre, en células binucleadas (19-27 y 10-18 AgNORs / célula, respectivamente) - este número fue superior a la cantidad registrada en células mononucleadas trofoblásticas en el mismo período. Por tanto, los AgNOR se pueden utilizar como marcadores del ciclo celular placentario proliferativo y se establece una relación entre el número de AgNOR y los días de gestación. Esta relación puede ser útil en el diagnóstico y pronóstico de varias patologías placentarias, incluidas las pérdidas de preñeces de embriones manipulados.

Aedes aegypti: egg morphology and embryonic development

Background The diseases for which Aedes aegypti is a vector are worrisome. The high vector competence of this mosquito, as well as its anthropophilia and ability to adapt to the urban environment, allows it to exploit many habitats, making its prevention an arduous task. Despite current disease control measures focused on the mosquito, the effectiveness in containing its dispersion still requires improvement; thus greater knowledge about this insect is fundamental. Methods Aedes aegypti egg morphology and embryonic development were analyzed from eggs of the insectary of the Institute of Biomedical Sciences of the University of São Paulo. Optical (light and confocal) and electronic (transmission and scanning) microscopy were used to analyze the morphological and ultrastructural features of the eggs. Embryos were observed in the initial (0–20.5 h after egg-laying), intermediate (20.6–40.1 h after egg-laying), and final (40.2–61.6 h) stages of development, and kept at a temperature of 28 °C ± 1 °C until collection for processing. Results Eggs of Ae. aegypti were whitish at the time of oviposition, and then quickly became black. The egg length was 581.45 ± 39.73 μm and the width was 175.36 ± 11.59. Access to the embryo was difficult due to the egg morphology, point of embryonic development, and difficult permeability of the exochorion (mainly in fixation). Only about 5% of the collected eggs were successfully processed. In the initial stage of embryonic development, characteristics suggestive of intense cellular activity were found. In the intermediate stage, the beginning of the segmentation process was evident. In the final phase, it was possible to differentiate the cephalic region and the thoracic and abdominal segments. Conclusion The chorion was found to be an important protective barrier and a limiting factor for the evaluation of the embryos and mosquito embryonic cells, indicating that further studies need to be carried out to identify the reason that this occurs.