Erika Toledo da Fonseca

Characteristics of the equine embryo and fetus from days 15 to 107 of pregnancy

In spite of numerous, substantial advances in equine reproduction, many stages of embryonic and fetal morphological development are poorly understood, with no apparent single source of comprehensive information. Hence, the objective of the present study was to provide a complete macroscopic and microscopic description of the equine embryo/fetus at various gestational ages. Thirty-four embryos/fetuses were aged based on their crown rump length (CRL), and submitted to macroscopic description, biometry, light and scanning microscopy, as well as the alizarin technique. All observed developmental changes were chronologically ordered and described. As examples of the main observed features, an accentuated cervical curvature was observed upon macroscopic examination in all specimens. In the nervous system, the encephalic fourth ventricle and the encephalic vesicles forebrain, midbrain, and hindbrain, were visualized from Day 19 (ovulation = Day 0). The thoracic and pelvic limbs were also visualized; their extremities gave rise to the hoof during development from Day 27. Development of other structures such as pigmented optical vesicle, liver, tail, cardiac area, lungs, and dermal vascularization started on Days 25, 25, 19, 19, 34, and 35, respectively. Light and scanning microscopy facilitated detailed examinations of several organs, e.g., heart, kidneys, lungs, and intestine, whereas the alizarin technique enabled visualization of ossification. Observations in this study contributed to the knowledge regarding equine embryogenesis, and included much detailed data from many specimens collected over a long developmental interval.

Embryonic Development of Endoderm in Chicken (Gallus gallus domesticus)

The poultry industry is a sector of agribusiness which represents an important role in the countrys agricultural exports. Therefore, the study about embryogenesis of the domestic chicken (Gallus gallus domesticus) has a great economic importance. The aim of this study was to evaluate embryonic development of the endoderm in chicken (Gallus gallus domesticus). Forty fertilized eggs of domestic chickens, starting from the 1st day of gestation and so on until the 19 days of the incubation were collected from the Granja São José (Amparo, SP, Brazil). Embryos and fetus were fixed in 10% formaldehyde solution, identified, weighed, measured, and subjected to light and scanning electron microscopy. The endoderm originates the internal lining epithelium of the digestive, immune, respiratory systems, and the organs can be visualized from the second day (48 h) when the liver is formed. The formation of the digestive system was complete in the 12th day. Respiratory system organs begin at the fourth day as a disorganized tissue and undifferentiated. Their complete differentiation was observed at the 10 days of incubation, however, until the 19 days the syrinx was not observed. The formation of immune system at 10th day was observed with observation of the spleen, thymus, and cloacal bursa. The study of the organogenesis of the chicken based on germ layers is very complex and underexplored, and the study of chicken embryology is very important due the economic importance and growth of the use of this animal model studies such as genetic studies. Microsc. Res. Tech. 76:803–810, 2013.

Características das papilas o dorso da língua de cabras (Capra hircus): estudo por de microscopia eletrônica de varredura e luz

The morphology of the lingual papillae of domestic goat (Capra hircus) was studied by scanning electron microscopy (SEM) and light microscopy (LM). Filiform, conical and lentiform papillae exert mechanical function whereas fungiform and valate papillae have gustative function. Filliform papillae were distributed all over the lateral and dorsal surfaces of the tongue. They present a conical shape with the thin ends pointed caudally; and possess several secondary processes, of different sizes, with the same orientation. Histological examination of these papillae revealed abundant queratinized tissue. Fungiform papillae were observed on the dorsal and lateral surface of the apical region and body of the tongue. Present a fungi-like shape, with a thick cornified epithelium and taste buds distributed on the surface. Lentiform papillae were distributed over the median line of the dorsal torus, presenting projections above the surface of the tongue. Some displayed pyramidal shapes; other were more flattened. Valate papillae were observed on the lateral surface of the posterior part of the torus and present a rounding shape delimited by a deep groove. These papillae possess taste buds on their lateral wall that open up on the groove. Conical papillae were observed on the lingual torus and present an extended shape, with a wide base and a blunt tip. Although the main morphological and structural characteristics of the lingual epithelium are species-specific, some features may be influenced by the type of food and alimentary habits. Therefore, the present study provides a histological and ultrastructural description of the tongue of the domestic goat fed with mixed food (grass and concentrate).

Osteogenesis in Chicken (Gallus gallus domesticus) and Expression of VEGF in this Process between 5 to 19 Days of Incubation

Poultry production is of great economic importance nowadays and it is important to constantly improve the production quality. In this context, the bird growth and adequate bone development are necessary for successful production. In this paper we evaluate the expression of VEGF and its importance in the osteogenesis process in embryonic and fetal tissues of Gallus gallus domesticus at different gestational ages. We observed that the Vascular Endothelial Growth Factor (VEGF) is essential in the formation of cartilaginous tissue and bone in the embryo and fetus of Gallus gallus domesticus.

Diaphragm morphology of guinea pig (Cavia porcellus).

The diaphragm is the main respiratory muscle. Along with other respiratory muscles, the diaphragm is responsible for the muscular contraction that generates the respiratory cycle and, as a consequence, the gaseous interchanges in the lungs. Guinea pigs (Cavia porcellus Linnaeus 1758) are largely used as experimental animals in many biology applications due to their easy management, low cost, and docile behavior. As the diaphragm exerts important effects on lung physiology and function, this study aimed at investigating the morphological characteristics of the muscle, through macroscopic, microscopic, and scanning electron microscopy to add reference data for future studies. We observed a “U”‐shaped tendineous center and its morphology was similar to other mammals. These results cooperate with the descriptive and comparative anatomy of mammals, besides can be used as control data for areas of surgery and stem cells. Microsc. Res. Tech. 76:316–320, 2013.

Embryonic development of chicken (Gallus Gallus Domesticus) from 1st to 19th day-ectodermal structures.

Birds occupy a prominent place in the Brazilian economy not only in the poultry industry but also as an animal model in many areas of scientific research. Thus the aim of this study was to provide a description of macro and microscopic aspects of the ectoderm‐derived structures in chicken embryos / fetuses poultry (Gallus gallus domesticus) from 1st to 19th day of incubation. 40 fertilized eggs, from a strain of domestic chickens, with an incubation period of 2–19 days were subjected to macroscopic description, biometrics, light, and scanning microscopy. All changes observed during the development were described. The nervous system, skin and appendages and organs related to vision and hearing began to be identified, both macro and microscopically, from the second day of incubation. The vesicles from the primitive central nervous system—forebrain, midbrain, and hindbrain—were identified on the third day of incubation. On the sixth day of incubation, there was a clear vascularization of the skin. The optic vesicle was first observed fourth day of development and on the fifth day there was the beginning of the lens formation. Although embryonic development is influenced by animal line as well as external factors such as incubation temperature, this paper provides a chronological description for chicken (Gallus gallus domesticus) during its embryonic development. Microsc. Res. Tech. 76:1217–1225, 2013.

Cultura, caracterização e diferenciação de precursores neurais do sistema nervoso central de porquinho-da-índia (Cavia porcellus Linnaeus, 1758)

Potentially neurogenic areas were initially identified by incorporation of bromodeoxyuridine (BrdU) in cells underlying the subventricular zone (SVZ) of the lateral ventricles wall, hippocampus and olfactory bulbs of newborn guinea pigs. Neural precursors from the SVZ were cultured in suspension, generating neurospheres (NSFs), which, upon dissociation were able to generate new NSFs. Upon culture in the absence of growth factors, cells dissociated from NSFs displayed evidence for neural differentiation, giving rise to cells from neural lineage. Flow cytometry analysis for of NSFs-derived cells after differentiation revealed approximately 13.3% nestin positive, 5.5% Beta-III-tubulin positive, 9% GFAP positive and 7.8% mGalC positive. Functional assays by measurement of calcium influx upon gamma butiric amino acid (GABA) and glutamate stimuli, revealed stimulation in differentiated cells, an indicator of neuronal differentiation. The ability of guinea pig SVZ cells to originate functional neurons in vitro is promising for research and towards a future use of neural stem cells in the therapy of neurological disorders.