Ultrastructural evaluation of the oocytes and spermatozoa of the scleractinian coral Mussismilia harttii.

Global coverage of living coral has declined by half since 1950s. Reef-building species have been severely impacted in this climate crisis scenario, compromising the future of coral reefs. Despite their importance, there is a lack of knowledge regarding the reproductive biology of scleractinian corals. In the present study, we evaluated through electron microscopy approaches, the gametes of the endemic Southwestern Atlantic coral Mussismilia harttii. We observed spherical oocytes with microvilli throughout the outer membrane. Fine granular material dispersed in cytoplasm, lipid granules, numerous yolk bodies, and mitochondria were identified in the oocytes. In addition, small Symbiodinium-like cells were observed, suggesting a vertical transmission from parental coral to oocytes. The spherical-head sperm presents a 9.3 ± 2.1 µm flagellum. The nucleus is located centrally in the head, and the centrioles are positioned between the nuclear base and the flagellar insertion, which is connected to the axoneme. This axoneme has a microtubular arrangement (9+2). Vesicles, underlining the inner plasma membrane, presented the same electron-dense pattern as the Golgi complex, and mitochondria positioned surrounding the axoneme. The vesicles present in the sperm may have a role as an acrosome since the oocytes do not develop any cell specialization for fertilization.

Exposure to the herbicide atrazine induces oxidative imbalance, morphological damage and decreased survival in juvenile fish

Synthetic herbicides have been intensively used in weed control, although often involved in environmental contamination, critically affecting non-target species. However, never was investigated the effect of commercial formulation using atrazine on developing juvenile fish exposed for 35 days. Juveniles (Astyanax altiparanae) (n = 600) were assigned to the following ATZ-exposed groups: 0 (CTR-control), 0.56 (ATZ0.56), 1.00 (ATZ1.00), 1.66 (ATZ1.66) and 11.66 (ATZ11.66) µg/L. We found a 36.6% decrease in juvenile survival rate in the ATZ11.66 group compared to control and other groups. Juveniles from ATZ11.66 also showed hyperglycemia and increased cortisol levels. Increased the imbalance oxidative with an increase in malondialdehyde (MDA) and Carbonylated proteins levels markers in muscle, gills, and liver. We also found increased activity of the antioxidant enzymes superoxide dismutase (SOD) in gills and SOD and catalase (CAT) in muscles from ATZ11.66 fish, and increased glutathione S-transferase (GST) activities in the liver from all exposed groups compared to control. The morphological consequences of this were loss of secondary lamella integrity, increased mucus-secreting cells, hyperplasia, and lamellar fusion, as well as increased aneurysms percentage. The liver showed vascular congestion associated with endothelial hyperplasia, steatosis, and a decrease in the nuclei percentage. Our results showed that exposure to a commercial formulation of ATZ at 11.66 µg/L can be causing an imbalance in the oxidative markers and morphological damages and decreased survival in a juvenile Neotropical species of great ecological relevance and commercial interest.

Short-term intake of deltamethrin-contaminated fruit, even at low concentrations, induces testicular damage in fruit-eating bats (Artibeus lituratus).

Deltamethrin (DTM) is a pyrethroid insecticide widely used for agricultural purposes. Exposure to DTM has proven to be harmful to humans, but whether low, environmental concentrations of this pesticide also poses a threat to wild mammals is still unknown. In Neotropical areas, bats play important roles in contributing to forest regeneration. We investigated the effects of DTM exposure on the reproductive function of male Neotropical fruit-eating bats (Artibeus lituratus), known for contributing to reforestation through seed dispersal in Neotropical Forests. Bats were assigned to 3 groups: control (fed with papaya); DTM2 (fed with papaya treated with DTM at 0.02 mg/kg) and DTM4 (fed with papaya treated with DTM at 0.04 mg/kg) for seven days. Bats from DTM2 and DTM4 groups showed increased testicular levels of nitric oxide and superoxide dismutase and catalase activities. The germinal epithelium from DTM4 bats showed non-viable cells and cell desquamation, indicating microscopic lesions and Leydig cells atrophy. Our results demonstrate the onset of cell degeneration that may affect the reproductive function in DTM exposed bats.

Curcuma longa as additive in the diet for Astyanax aff. bimaculatus.

The aim of the present study was to evaluate the effect of turmeric (Curcuma longa) as additive in the diet for Astyanax aff. bimaculatus. Fish (0.83 ± 0.04 g) were fed, for 60 days, with six diets containing 0.0, 20.0, 40.0, 60.0, 80.0, and 100.0 g turmeric kg-1 feed. There was an increasing linear effect of turmeric on the thickness of the muscular layer, and height and width of the folds of the intestine. In the liver, a quadratic effect was observed of turmeric on the percentage of hepatocyte cytoplasm and a decreasing linear effect on the percentage of sinusoid capillaries. A quadratic effect was also observed of turmeric on the liver glycogen. There was no effect of turmeric on the antioxidant activity in the liver, carcass composition or productive performance of the fish. Thus, we concluded that Curcuma longa has trophic effects on the epithelium and the muscular layer of the intestine of A. aff. bimaculatus. Additionally, low levels of Curcuma longa cause increased deposition of liver glycogen and high levels cause reduction.

Transport of Astyanax altiparanae Garutti and Britski, 2000 in saline water / Transporte de Astyanax altiparanae Garutti and Britski, 2000 em água salinizada

Two experiments were performed. The first aimed to assess the tolerance of fingerlings Astyanax altiparanae to water salinity. Fish were exposed to salinity of 0, 3, 6, 9, 12 or 15 g NaCl L-1 for 96 hours. The fish mortality was 0%, in the levels of 0, 3 and 6 g L-1; 75% in the level of 9 g L-1and 100% at 12 and 15 g L-1 of common salt. The second experiment aimed to assess the parameters of water quality, mortality and blood glucose during transport. For this, A. altiparanae were stored in plastic bags at 22, 30 and 37 g of fish L-1 stocking densities and salinity of 0, 3, 6 and 9 g L-1, for. Fish showed similar mortality levels in the different salinities and stocking densities. The increase in fish density reduced the dissolved oxygen levels and salinity decreased the pH. The blood glucose levels were higher in those fish with 0 g L-1 salinity and higher stocking densities. The addition of salt to the water reduces the stress responses of A. altiparanae during transport.

Foram realizados dois experimentos. O primeiro teve o objetivo de avaliar a tolerância de alevinos de Astyanax altiparanae a salinidade da água. Os peixes foram submetidos às salinidades de 0, 3, 6, 9, 12 ou 15 g de NaCl L-1 durante 96 horas. A mortalidade dos peixes foi de 0%, nos níveis de 0, 3 e 6 g L-1; de 75% no nível de 9 g L-1 e de 100% em 12 e 15 g L- 1 de NaCl. No segundo experimento, objetivou-se avaliar os parâmetros de qualidade de água, mortalidade e a glicose sanguínea durante o transporte. Para isso, A. altiparanae foram estocados em sacos plásticos nas densidades de 22, 30 e 37 g de peixe L-1 e salinidades de 0, 3, 6 e 9 g de NaCl L-1. A mortalidade foi semelhante nas diferentes salinidades e densidades de estocagem. O aumento da densidade de peixes reduziu o nível de oxigênio dissolvido e a salinidade da água reduziu o pH. Os níveis de glicose sanguínea foram maiores nos peixes expostos a salinidade de 0 g L-1 e nas maiores densidades de estocagem. A adição de sal na água reduz as respostas de estresse em A. altiparanae durante o transporte.