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Cardiogenesis is similar in all vertebrates, but differences in the valvuloseptal morphogenesis among non-crocodilian reptiles, birds, and mammals are noted. The origin of mesenchymal structures such as valves that regulate the passage of blood and the formation of partial septa that prevent the complete mixing of oxygen-rich and low-oxygen blood present in adult chelonians are essential in the evolutionary understanding of complete septation, endothermy and malformations, even in mammals. In this context, this study analyzed the heart morphogenesis of Podocnemis unifilis (Testudines: Podocnemididae) from the 4th to the 60th day of incubation. We identified the tubular heart stage, folding of the cardiac tube and expansion of the atrial and ventricular compartments followed by atrial septation by the septum primum, ventricle septation by partial septa, outflow tract septation and the formation of bicuspid valves with cartilage differentiation at the base. The formation of the first atrial septum with the mesenchymal cap is noted during the development of the atrial septum, joining the atrioventricular cushion on the 17th day and completely dividing the atria. Small secondary perforations appeared in the mid-cranial part, observed up to the 45th day. Partial ventricle septation into the pulmonary, venous, and arterial subcompartments takes place by trabeculae carneae thickening and grouping on the 15th day. The outflow tract forms the aorticopulmonary and interaortic septa on the 16th day and the bicuspid valves, on the 20th day. Therefore, after the first 20 days, the heart exhibits a general anatomical conformation similar to that of adult turtles.

This study aimed to describe pronephros and mesonephros morphology during the embryonic development of Podocnemis expansa. Eggs were collected on an artificial beach at Balbina, Amazonas, Brazil, during the entire incubation period (mean of 59 days). The kidney-gonad complex was processed using light microscopy and the mesonephros using transmission electron microscopy. The pronephros was present for the first time on stage 4, composed of external glomeruli devoid of a capsule, protruding into the coelomic cavity, and internally composed of a capillary network. The pronephros degenerated after development stage 15. The first sign of the appearance of the mesonephros occurred around stage 8, indicated by the early formation of renal corpuscles. The mesonephros comprised an renal corpuscles, neck segment, proximal tubule, intermediate segment, distal tubule, collector tubule, and collector duct. Ultrastructural analysis of the mesonephros brush border was done in the proximal tubule, and the presence of cells with structural characters indicative of secretory activity was detected in the juxtatubular region. Renal corpuscles and proximal tubules were the main components that underwent morphological alterations during mesonephros degeneration. The pronephros is a transient kidney, and the mesonephros became the functional embryonic kidney in P. expansa. Mesonephros degeneration occurs in the cranial-caudal direction, and histologically, the degeneration is identified by changes in the morphology of the renal corpuscle and proximal tubule. However, the mesonephros is still present after hatching.

The egg is one of the fundamental parts of the life cycle of Neoechinorhynchus buttnerae, and this stage involves the acanthor larva. It is also the infection phase for the intermediate host. Under normal conditions, the larva inside the egg can survive for months in the environment; however, information regarding this phase of life of the parasite is scarce. In addition, there is no quantitative information about the structural composition of the parasite's body from a histological point of view. Such information is essential in order to support decisions aimed at controlling infestations by these parasites in fish farming. This study aimed to present a detailed description of the stages of embryonic development of N. buttnerae eggs, as well as a stereological evaluation of the body of adult females of the parasite. Three phases of development characterized the eggs: cell division (with four stages), formation of the internal nuclear mass (with four stages) and formation of the acanthor larva (with five stages). The ovary comprised 26.61% of the volume of the animal and most of it contained eggs (21.28%), ovarian balls (3.88%) and empty spaces (1.45%). These results are of great importance and will support future studies that seek to interrupt the life cycle of this parasite.

The egg is one of the fundamental parts of the life cycle of Neoechinorhynchus buttnerae, and this stage involves the acanthor larva. It is also the infection phase for the intermediate host. Under normal conditions, the larva inside the egg can survive for months in the environment; however, information regarding this phase of life of the parasite is scarce. In addition, there is no quantitative information about the structural composition of the parasite's body from a histological point of view. Such information is essential in order to support decisions aimed at controlling infestations by these parasites in fish farming. This study aimed to present a detailed description of the stages of embryonic development of N. buttnerae eggs, as well as a stereological evaluation of the body of adult females of the parasite. Three phases of development characterized the eggs: cell division (with four stages), formation of the internal nuclear mass (with four stages) and formation of the acanthor larva (with five stages). The ovary comprised 26.61% of the volume of the animal and most of it contained eggs (21.28%), ovarian balls (3.88%) and empty spaces (1.45%). These results are of great importance and will support future studies that seek to interrupt the life cycle of this parasite.

Sex steroid hormones are critical in gonadal differentiation in turtles. The gonads are not the only organs responsible for producing these hormones during this phase. Mesonephros play an important role in steroidogenesis. The present study aimed to investigate the presence of steroidogenic cells in mesonephros of

INTRODUCTION: Electron microscopy (EM) is a rapid and effective tool that can be used to create images of a whole spectrum of virus-host interactions and, as such, has long been used in the discovery and description of viral mechanisms. METHODS: Electron microscopy was used to evaluate the pulmonary pathologies of postmortem lung sections from three patients who died from infection with SARS-associated coronavirus 2 (SARS-CoV-2), a new member of the Coronaviridae family. RESULTS: Diffuse alveolar damage (DAD) was predominant in all three patients. The early exudative stage was characterized principally by edema and extravasation of red blood cells into the alveolar space with injury to the alveolar epithelial cells; this was followed by detachment, apoptosis, and necrosis of type I and II pneumocytes. The capillaries exhibited congestion, exposure of the basement membrane from denuded endothelial cells, platelet adhesion, fibrin thrombi, and rupture of the capillary walls. The proliferative stage was characterized by pronounced proliferation of type II alveolar pneumocytes and multinucleated giant cells. The cytopathic effect of SARS-CoV-2 was observed both in degenerated type II pneumocytes and freely circulating in the alveoli, with components from virions, macrophages, lymphocytes, and cellular debris. CONCLUSIONS: Viral particles consistent with the characteristics of SARS-CoV-2 were observed mainly in degenerated pneumocytes, in the endothelium, or freely circulating in the alveoli. In the final stage of illness, the alveolar spaces were replaced by fibrosis.

Farming of Amazonian native fish species holds great promise. One species whose characteristics make it suitable for intensive farming is tambaqui (Colossoma macropomum). However, there is a lack of consensus about the most suitable stocking density (SD) for intensive farming. More information on the physiology of fish in farming systems is thus required, as this would increase our understanding of the effects of stress on these fish. The aim of this study was therefore to evaluate the effect of different SDs on the hematology and plasma protein profile of tambaqui. To this end, juvenile tambaqui were exposed to the following different SDs (kg/m3) for 96 h: SD1 = 2.11; SD2 = 8.31; SD3 = 16.34; and SD4 = 27.40. Water quality was monitored, and blood was collected for hematological analysis and electrophoresis (SDS-PAGE) to analyze plasma protein and immunoglobulin profiles. Gill filaments were removed and the number of parasites (monogenoids) was counted. Multivariate PCA analysis revealed a strong positive association between the highest SDs (SD3 and SD4) and parasite count, immune cells (eosinophils, thrombocytes, monocytes and lymphocytes) and water ammonia and nitrite levels. Conversely, the highest SDs were negatively associated with water quality variables (pH, turbidity, conductivity and O2 content) and blood hematocrit. The results show that the highest SDs contributed to a deterioration in water quality, leading to increased MetHb levels, gill parasitism, an increase in the number of defense cells, altered protein profile and stimulation of immunoglobulin production. These changes suggest that the welfare of tambaqui is adversely affected by high SDs and increase our understanding of the effects of crowding stress on the physiology of the species.

In this study, two mouse hyperimmune sera were produced, one using extract from the stinger of the stingray Potamotrygon motoro and the other using extract from the dorsal region of the same species and their cross-reactivity with extracts from the following species of stingrays from the Amazon basin was investigated using Western blot and dot ELISA: Paratrygon aiereba, Plesiotrygon iwamae, Potamotrygon orbignyi and Potamotrygon schroederi. The results show that the dorsal extract was as immunogenic as the stinger extract and induced high levels of antibodies, which reacted with homologous and heterologous antigens, indicating that both types of extract may be suitable for use in the production of antivenom to treat victims of envenomation by stingrays.

Knowledge of embryonic development is important for choosing strategies for nest conservation, and reducing negative effects on eggs and embryos of turtle species subject to human and natural interference, as is the case of Podocnemis expansa in the Amazon. Nine P. expansa nests located in Balbina, Amazonia, Brazil, were used to describe embryonic development. An embryo was collected each day, totaling 240 embryos. The specimens were fixed in Bouin’s and Karnovsky’s solutions for macroscopic analysis and scanning electron microscopy, respectively. The incubation period lasted between 58 and 64 days with a mean nest incubation temperature of 30.3 °C. The main characteristics used for description and comparison of embryonic development were: development of the eyes, the mandibular process, limbs, carapace and plastron. We found that the timing of appearance and disappearance of structures in P. expansa were more advanced than in other turtle species. Furthermore, P. expansa displays some unique characteristics during its normal development, such as craniofacial morphology, frontonasal groove and carapace and plastron characteristics.

Made available in DSpace on 2016-09-23T15:19:52Z (GMT). No. of bitstreams: 1 RELATORIO_FINAL_-_PIBIC_-_0046.pdf: 713278 bytes, checksum: adc75015e92a31ffbf805b7db0ae8f73 (MD5) Previous issue date: 2012-07-31 FAPEAM Durante o cultivo intensivo de peixes, desequilíbrios nos processos de transformação da amônia podem acarretar elevados níveis de nitrito (NO2-) no meio aquático, o nitrito logo é absorvido através das brânquias que em poucas horas acumula-se no sangue e tecidos dos animais, e a concentração chega a ser muito superior da encontrada no ambiente. Das consequências devido a intoxicação pelo nitrito, pode se ressaltar duas: a primeira se da à direta ação do NO2- sobre a molécula da hemoglobina (Hb) transformando-a em metahemoglobina (MetHB) onde a mesma torna-se incapaz de de ligar e liberar oxigênio O2 aos tecidos. A partir disso alguns órgãos vitais para a homeostase enfrentam períodos de severa hipóxia devido a exposição ao nitrito. Dentre esses órgãos destaca-se o fígado, mas embora a espécie do tambaqui ser amplamente utilizada em meios de aquacultura, não se tem informações a respeito dos efeitos tóxicos do nitrito sobre a organização hepática do tambaqui. O presente projeto tem a finalidade de fazer uma análise morfométrica do fígado de tambaqui submetidos à exposição por nitrito, para se poder ter mais informações sobre a histologia quantitativa desta espécie.