Effects of blood metal(loid) concentrations on genomic damages in sharks.

The use of effect biomarkers has contributed to the understanding of the sublethal effects of contaminants on different organisms. However, the analysis of genotoxic markers as an indicator of organism and environmental health in sharks is underexplored. Thus, the present study investigated the relationship between the genomic damage frequency in erythrocytes and metal(loid) concentrations in whole blood of three shark species (Galeocerdo cuvier, Negaprion brevirostris and Ginglymostoma cirratum), taking into account climatic seasonality. The results showed that G. cuvier, an apex predator, presented the highest total erythrocyte genomic damage frequencies together with the highest mean whole blood concentrations of Al, Cd, Cr, Fe, Mn, Ni, Pb and Zn. The shark N. brevirostris also presented high levels of metal(loid), indicating a greater susceptibility to these contaminants in species that preferentially feed on fish. In contrast, G. cirratum, a mesopredator, presented the lowest erythrocyte damage frequencies and whole blood metal(loid) concentrations. The presence of micronuclei was the most responsive biomarker, and Al, As and Zn had an important effect on the genomic damage frequencies for all species evaluated. Zn concentration influenced the binucleated cells frequencies and Al concentration had an effect on the total damage and micronuclei frequencies in G. cuvier and N. brevirostris. Binucleated cells and blebbed nuclei frequencies were affected by As concentration, especially in G. cirratum, while showing a strong and positive correlation with most of the metals analyzed. Nonetheless, baseline levels of metal(loid) blood concentrations and erythrocyte genomic damage frequencies in sharks have not yet been established. Therefore, minimum risk levels of blood contaminants concentrations on the health of these animals have also not been determined. However, the high genomic instability observed in sharks is of concern considering the current health status of these animals, as well as the quality of the environment studied.

Genetic diversity and gene flow of the threatened Brazilian endemic parrotfish Scarus trispinosus (Valenciennes, 1840).

The greenback parrotfish, Scarus trispinosus, is the largest herbivorous fish inhabiting Southwestern Atlantic reefs, and was recently included in the IUCN red list of threatened species as endangered due to the overexploitation of their populations. The aim of this work was to evaluate the existence of structured populations (i.e. genetic unities) along a coast of approximately 2000 km of the NE Brazilian coast. The transferability of 17 primers synthesized for Scarus rubroviolaceus was tested for S. trispinosus and five transferable loci were validated and used. Two localities within the Abrolhos Bank, off the Central Brazilian coast (Corumbau and Caravelas) and in close proximity to the MPA, which encompasses the largest remnants of the S. trispinosus population, exhibited higher levels of genetic richness. Remaining locations, Pernambuco, Porto Seguro and Rio Grande do Norte exhibited lower genetic diversity. We found no genetic differences among sampled localities however, when those samples were gathered into latitudinal groups (northern vs southern) a subtle but significant genetic substructuring was revealed. It is proposed that a combination of high local individual admixture favoured by habitat connectivity drived genetic homogeneity at regional scales while larval dispersal contributed to heterogeneities observed at large scales maintaining gene flow through oceanographic currents.

Poecilia vivipara Bloch & Schneider, 1801 (Cyprinodontiformes, Poeciliidae), a guppy in an oceanic archipelago: from where did it come?

Poecilia vivipara, a small euryhaline guppy is reported at the Maceió River micro-basin in the Fernando de Noronha oceanic archipelago, northeast Brazil. However, the origin (human-mediated or natural dispersal) of this insular population is still controversial. The present study investigates how this population is phylogenetically related to the surrounding continental populations using the cytochrome oxidase I mitochondrial gene from eleven river basins in South America. Our phylogenetic reconstruction showed a clear geographical distribution arrangement of P. vivipara lineages. The Fernando de Noronha haplotype fell within the 'north' clade, closely related to a shared haplotype between the Paraíba do Norte and Potengi basins; the geographically closest continental drainages. Our phylogenetic reconstruction also showed highly divergent lineages, suggesting that P. vivipara may represent a species complex along its wide distribution. Regarding to the insular population, P. vivipara may have been intentionally introduced to the archipelago for the purpose of mosquito larvae control during the occupation of a U.S. military base following World War II. However, given the euryhaline capacity of P. vivipara, a potential scenario of natural (passive or active) dispersal cannot be ruled out.

Are Brazilian cervids at risk of prion diseases?

Prion diseases are neurodegenerative fatal disorders that affect human and non-human mammals. Chronic Wasting Disease (CWD) is a prion disease of cervids regarded as a public health problem in North America, and polymorphisms at specific codons in the PRNP gene are associated with this disease. To assess the potential CWD susceptibility of South American free-ranging deer, the presence of these polymorphisms was examined in Mazama gouazoubira, Ozotoceros bezoarticus and Blastocerus dichotomus. Despite the lack of CWD reports in Brazil, the examined codons (95, 96, 116, 132, 225, and 226) of the PRNP gene showed potential CWD susceptibility in Brazilian deer. Low abundancy of deer in Brazil possibly difficult both CWD proliferation and detection, however, CWD surveillance may not be neglected.

Trends on the Karyotype Acrocentrization Within Carangidae (Perciformes): A New Phylogenetic Evidence About a Traditional Marine Paradigm.

Carangidae is a morphologically diverse family of marine fish, characterized by stable karyotypes, predominantly with 2n = 48, composed of acrocentric chromosomes (A). This stability is shared with other families of the order Perciformes, which resulted in the hypothesis that 48A is a plesiomorphic karyotype of the group. We tested this hypothesis in the Carangidae family using comparative phylogenetic methods, investigating the evolution of karyotype characters (including chromosome number, morphology, and number of chromosome arms per karyotype [fundamental number, FN]). Our analyses revealed that 2n = 48 is most likely the ancestral chromosome number for the family. However, an extremely variable number of FNs, always above 48, was observed in basal clades within the family and sister groups. On the other hand, the reduced FN = 48 was consistently observed only in the most derived clades, indicating a tendency for acrocentrization. The number of acrocentric chromosomes apparently was accompanied by a trend of reduction in the genome size (1C-value), suggesting that these changes might be correlated. Our data contradict the marine fish hypothesis that the 2n = 48 acrocentric karyotype is plesiomorphic, at least for Carangidae, and reveal the importance for the correct interpretation of karyotype in a temporal and phylogenetic context.

Assessment of the association between micronuclei and the degree of uterine lesions and viral load in women with human papillomavirus.

Infection by human papillomavirus (HPV) is among the main etiologies of cervical cancer. The expression of oncogenic viral proteins enables the onset of the virus, which can trigger the carcinogenic process. One of the main characteristics of this process is the loss of genome stability, including chromosome stability. The micronucleus test is a cytogenetic method for the detection of genetic alterations that change chromosome behavior during cell division resulting in the formation of micronuclei. This method has been applied for the early detection of DNA damage in individuals with a greater likelihood of developing cancer. The aim of the present study was to assess the association between micronucleus expression and the degree of cytological lesions and viral load in patients with HPV. The micronucleus analysis revealed differences in the number micronuclei found in the groups, which ranged from 0.00067 to 0.00133 in the control group and 0.00267 to 0.02433 among patients with HPV. Statistically significant differences (p<0.05) were found in the number of micronucleated cervical cells between the patients and healthy women. Moreover, significant associations were found between micronucleus expression and both the degree of uterine lesions (r2=0.7237; r=0.8507; p=0.000002) and viral load (r2=0.7012; r=0.8374; p=0.000004). The findings demonstrate the efficacy of micronucleus analysis in monitoring risks to human health.