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Biologia do desenvolvimento de tartaruga amazônica (Kinosternon scorpioides) em cativeiro

2020-01-01T00:00:00Z

Título: Biologia do desenvolvimento de tartaruga amazônica (Kinosternon scorpioides) em cativeiro Abstact: The jurará has been the target of great exploratory activity in the Amazonas Delta and in the State of Maranhão in the Baixada Maranhense. There are no reports in the literature on the population density of the species in a natural environment, although a significant decrease has been observed in the region under study. This research aims to characterize the developmental biology of K. scorpioides, based on sexual differentiation in the embryonic period and development of the gonads after birth. For the phenotypic description, 75 eggs were incubated at an average temperature of 28 ° C and the embryos were collected at regular intervals of 1 week. There were 15 embryonic stages for species with a 15-week reproductive development cycle, equivalent to 105 days of incubation. Only at 42 days (6th week) was the morphological characterization of a chelonian noticed and at the 12th week (Stage XII) the phenotypic characterization of the species Kinosternon scorpioides. Regarding the expression of specific genes in sexual determination, the immunoreaction of the enzyme cytochrome p450 aromatase and Sox 9 were positive in the mesonephro-gonad complex in all embryonic phases studied. In Kinostenon scorpioides, the phases of embryonic development occurred in moments of structural formations similar to other turtles, even at different times

Biomarcadores histológicos, enzimáticos e expressão gênica de glutationa S-transferase e catalase em Sciades herzbergii (Bloch, 1794, Pisces, Ariidae) para o monitoramento de impactos antrópicos na Baía de São Marcos-MA

2024-01-01T00:00:00Z

Título: Biomarcadores histológicos, enzimáticos e expressão gênica de glutationa S-transferase e catalase em Sciades herzbergii (Bloch, 1794, Pisces, Ariidae) para o monitoramento de impactos antrópicos na Baía de São Marcos-MA Abstact: The objective of the present study was to evaluate histological, enzymatic and gene expression biomarkers of glutathione S-transferase (GST) and catalase (CAT) in fish of the species Sciades herzbergii (Bloch, 1794), collected under the area of industrial and port influence and an area of environmental preservation in the Bay of São Marcos, Maranhão. Specimens of S. herzbergii (Bloch, 1794), were collected every six months between 2019 and 2021 (March and July) at two times of the year (rainy and dry) in São Marcos Bay: Porto Grande (PG), a potentially impacted region; and Ilha dos Caranguejos (IC), an area with the lowest impact. Sediment samples were collected for chemical analysis of trace metals and polycyclic aromatic hydrocarbons (PAHs). Morphometry, GST and CAT enzyme activity, and branchial and hepatic alterations (for the two years of the study) and GST and CAT gene expression (for 2021) were analyzed for each specimen. The results of the HPA analyses of the sediments showed that in the PG region the concentrations were significantly (p<0.05) higher compared to IC. Most of the trace elements present in the sediments were in accordance with the levels recommended by the Brazilian regulatory standards. Al, Fe, Mn and Sr showed differences between the sampled sites with higher values. The morphometric data of CI fish in the rainy season showed a high average of weight and size compared to PG for the two years of collections. The alterations in the gills of the fish identified in HF were: lamellar fusion, epithelial displacement and tissue degeneration. In PG, the following parameters were: epithelial displacement, lamellar fusion, necrosis and hyperplasia. The changes in the liver observed were: fibrosis, necrosis and melanomacrophage centers in both areas. GST and CAT activities in gills and livers of fish from HF showed high averages in the rainy season in 2019. In 2021, GST and CAT in gills and liver of fish also showed higher averages in the rainy season in PG. The gene expression of GST and CAT were not expressed in gills and livers of fish in PG and IC for this study. However, in this study, the expression of the endogenous genes Beta- actin, 18S ribosomal RNA, 28S ribosomal RNA in gills and livers of S. herzbergii (Bloch, 1794) was identified for the first time, indicating the quality of the biological material. The results of the selected biomarkers (enzymatic and histological) suggest that the fish in both areas are responding negatively to the impacts on the environment, especially the fish caught in PG, which demonstrate more significant changes. Endogenous genes (Beta-actin, 18S ribosomal RNA, 28S ribosomal RNA) showed positive responses indicating the reliability of the method applied to S. herzbergii (Bloch, 1794). The histological, enzymatic and gene expression biomarkers of GST and CAT in S. herzbergii (Bloch, 1794) were able to differentiate the quality and impacts from two areas of São Marcos Bay, Maranhão.

Adaptações morfofisiológicas de Cichla kelberi Kullander & Ferreira, 2006 (Cichliformes: Cichlidae) em diferentes estágios reprodutivos

2025-10-16T00:00:00Z

Título: Adaptações morfofisiológicas de Cichla kelberi Kullander & Ferreira, 2006 (Cichliformes: Cichlidae) em diferentes estágios reprodutivos Abstact: The yellow peacock bass (Ciclha kelberi) has been introduced into reservoirs in Brazil, and information on its energetic, reproductive, gonadal maturation, and lipid profile is still scarce, especially in the state of Maranhão. Such studies are limited and restricted to lake regions. Therefore, this study aims to evaluate the morphophysiological, energetic, and cellular adaptations of C. kelberi at different reproductive stages in the Lençóis Maranhenses National Park, Barreirinhas, Maranhão. Seventy-six specimens were collected: 30 females and 46 males. The captured specimens were weighed and their livers, stomachs, and gonads were removed for biometric and histological analysis. The dorsal muscle, liver, and venter were also removed to determine tissue lipid concentrations. In the microscopic evaluation of the gonads, the following stages were observed: maturing (44.7%), mature (28.9%), and emptied (26.3%). Females predominated in the emptied stage and males in the maturing stage. In females, cells were visible in all stages of oocyte development. The sex ratio for sampling was 1.5 males to 1 female. The highest frequency of individuals was in lengths between 31.0 and 41.0 cm (49.9%), males were larger, with a significant difference between the sexes (p = 0.01). Females obtained positive allometry (b = 3.1) and males negative (b = 2.9). The condition factor and the gonadosomatic index of the species showed elevations in the mature gonadal development stage, indicating well-being and reproductive fitness. The hepatosomatic index (HSI) of males (0.7) was higher than that of females (0.5). Males showed an increase as gonadal maturation progressed, while females showed a decline in the mature stage. Lipid analysis demonstrated that the venterchae is where the highest concentration is found (7.6%). Females presented greater lipid fluctuations in the tissues and organs studied, while in males, the fluctuations were discreet and the percentages were more constant. The coefficient of determination showed that 45% of stomach weights were influenced by fish weight. The stomach condition factor and weight were lower in females than in males. The species efficiently converts environmental resources into energy for maintaining its ecology and reproduction. More detailed studies on the ecology and mechanisms that influence the adaptive and reproductive success of the species are needed to implement effective management measures.

Variabilidade fenotípica e genética de Kinosternon scorpioides (Linnaeus, 1766)

2019-01-01T00:00:00Z

Título: Variabilidade fenotípica e genética de Kinosternon scorpioides (Linnaeus, 1766) Abstact: The Kinosternon scorpioides species is a small freshwater chelonian distributed throughout the Americas, and in Brazil mainly in the north and northeast regions. With the average goal of morphological and genetic changes in Brazil and Colombia, used as traditional and geometric morphometric techniques, in addition to molecular analyzes (mitochondrial and nuclear DNA). All samples sampled have phenotypic characteristics typical of the species, color, organization and quantity of chemical plates. Linear morphometry indicates that there is a statistical difference between sex, with males being narrower and shorter in relation to females, while geometric morphometry shows shape variation for each sex. In relation to the evaluation between the variations, from the geometric morphometry, these are organized in groups, selected according to the sampled geographic regions, those that are close to each other and share or even format. The genetic study indicates that Brazilians are different from Colombians, with an average genetic diversity of 3% (mtDNA). This variation was accompanied by the results of the microsatellites, with the FSt fixation index and initial coefficient, in addition to revealing what these statistics are structured, with low inbreeding rates. The results are important for the knowledge of the Brazilian species K. scorpioides, and other subsidiary studies on conservation and conservation.