Anais da Academia Brasileira de Ciencias最新文献

Heavy metal pollution is a global environmental problem. Enterococci have been recognized as sentinels of environmental pollution.This study investigates metal tolerance genes (arsA, merA, and tcrB) among enterococci isolated from fecal samples of domestic and wild animals from Atlantic Forest, Pampa biomes, and coastal regions of southern Brazil. Among the 238 enterococci analyzed, 38% harbored arsA_I/arsA_II and 10% contained tcrB, while none tested positive for merA genes. These results suggest that the selective pressure exerted by anthropogenic activities in the animals' habitats may contribute to the occurrence of heavy metal tolerance genes in host-associated enterococci.

Biological inventories are essential tools for understanding parasite diversity. In this study, we describe the helminth parasite communities associated with anuran amphibians from five localities within the Caatinga domain of Northeastern Brazil. A total of 1,198 individuals, belonging to 22 species and six anuran families (Bufonidae, Hylidae, Leptodactylidae, Microhylidae, Odontoprhynidae, and Phyllomedusidae), were examined. Of these, 629 specimens (52.5%) were parasitized, and 27,004 helminths were recovered. The helminths represented 34 taxa, including 24 Nematoda, 7 Digenea, 1 Cestoda, and 2 Acanthocephala. We present parasitological descriptors such as prevalence, abundance range, infection site, and life stage. Additionally, we report 18 new host-parasite records and provide updated data on geographical occurrence. Our findings emphasize the importance of regional surveys in expanding knowledge on host-parasite interactions and in highlighting hidden components of biodiversity within the Caatinga biome.

Cyanobacteria, diverse prokaryotes, are impacted by anthropogenic activities introducing chemical elements into marine environments, affecting benthic organisms. This study investigated benthic filamentous cyanobacteria and heavy metal in their biomass in two reef systems on Bahia coast, Brazil. Taxonomic identification was done using optical and electron microscopy, and heavy metals were analyzed using Energy Dispersive X-Ray Spectroscopy. A total of 108 samples were analyzed: four species were identified in Praia de Tubarão (TB), the more anthropized area (Trichocoleus tenerrimus, Lyngbya confervoides, L. aestuarii and Lyngbya sp.), while ten species were found in Praia Sítio do Conde (SCB), a less anthropized area (Spirulina subsalsa, S. subtilis, S. major, Calothrix scopulorum, Phormidium sp., Oscillatoria margaritifera, O. nigro-viridis, L. confervoides, L. aestuarii, and L. semiplena). Fourteen metals were detected in TB and only four metals in SCB. These findings suggest that variations in species richness and metal diversity in cyanobacterial biomass are related to different levels and types of anthropogenic influence between the areas. This study demonstrates that cyanobacteria can accumulate heavy metals, serving as bioindicators of environmental quality in coastal areas, which is crucial for understanding the impact of these metals on aquatic environments, especially in areas with varying levels of anthropogenic influence.

The Brazilian free-tailed bat (Tadarida brasiliensis) is a widely distributed Neotropical Molossidae species with significant ecological importance in pest control. Despite its broad range, the genetic diversity and population structure of South American populations remain poorly understood. This study assessed the genetic diversity, population structure, and demographic history of T. brasiliensis in southern Brazil (Capão do Leão) compared to available sequences from South, North, and Central American populations using COI and D-loop mitochondrial markers. Bayesian and coalescent-based analyses revealed deep divergence (~8.9 Mya) between northern and southern lineages, likely influenced by Andean uplift and Pleistocene climatic shifts. High genetic diversity was observed in southern populations, with distinct clades suggesting historical isolation. Population structure analyses confirmed significant differentiation between regions, with isolation-by-distance as a key driver. Demographic tests indicated post-glacial expansions (~0.5-0.12 Mya) in southern populations. These findings suggest that T. brasiliensis in South America comprises a single evolutionary lineage with complex demographic dynamics shaped by historical biogeographic barriers. The study highlights the need for further research on migratory connectivity and conservation strategies for this ecologically important species.

Emissions of greenhouse gases in the atmosphere by burning fossil fuels to generate electric energy has become a major environmental concern. In this scenario, alternative clean sources, such as wind energy, are becoming the top substitute option for supplying electricity and reducing gases emissions. Brazil has huge potential for offshore wind energy. The main challenge, however, is to guarantee the proper installation of these facilities, minimizing risks and ensuring safe operation during its lifetime. To achieve that goal, extensive investigations regarding several geological, engineering and environmental factors must be conducted. Marine geophysical tools have proven to be a reliable, fast and cost-effective way to map the seafloor. This paper provides a review of how different countries are gathering data to map, manage and mitigate seabed features and risks on their offshore wind farm projects. It is shown that, despite many common characteristics, each country has specific rules regarding the survey design. The goal is to provide an overview of the "best practices", and to serve as a baseline for Brazilian regulatory agencies and other stakeholders to design effective hydrographic and geophysical surveys extracting maximum value and knowledge, minimizing geological risks and environmental impacts, keeping cost efficiency for all stakeholders in the operation.

This study investigates the core RT-01-PB from the Miriri Sub-Basin, Paraíba Basin, analyzing planktic and benthic foraminifera from the upper Campanian to lower Maastrichtian. The strata belong to the Itamaracá and Gramame formations. Lithostratigraphic, biostratigraphic, and paleoenvironmental interpretations were developed using microbiofacies and benthic foraminiferal morphogroups. Fifty samples were processed for foraminiferal recovery, and thirty-five petrographic thin sections were analyzed to identify bioclastic constituents and diagenetic features, aiming to describe and classify the microbiofacies. Two planktic foraminiferal zones were identified: Gansserina gansseri Zone (upper Campanian-lower Maastrichtian) and Contusotruncana contusa Zone (lower Maastrichtian). Benthic foraminifera were classified into morphogroups by morphology and habitat, associating strata with depositional environments. Petrographic analysis revealed five microbiofacies types, including the first occurrence of larger benthic foraminifera in Brazil during the Upper Cretaceous. During the upper Campanian-lower Maastrichtian, the Miriri Sub-Basin was a platform environment, ranging from inner to mid-ramp (0-100 m depth) under oligotrophic conditions, with predominance of epifaunal forms. In the lower Maastrichtian, a middle-outer ramp (100-200 m) shifted to mesotrophic conditions, marked by increased infaunal foraminifera and authigenic phosphate, coincident with a gamma-ray peak. These data offer perspectives on climatic and palaeoenvironmental variations across the northern South American Platform during the Campanian-Maastrichtian.

To introduce the scientific method to children in early ages is challenging; however, it enables covering simultaneously several educational subjects and influences positively student formation and the society in future. Accordingly, this research involved two girls, aged nine and eleven, who were encouraged to investigate why a fungus that causes mold on an orange makes it soft and rotten. The girls assisted by a research team, composed mainly women scientists, observed and compared a ripe orange with a moldy one, afterwards formulating a hypothesis, and simple experiments to test it. This methodological pipeline applied with experimentation covering all steps of the scientific method introduced the children to topics such as mathematics, microbiology, chemistry, biochemistry, and biotechnology, sparking their interest in science. This article highlights the importance of stimulating scientific curiosity from an early age and addresses gender disparity in science by promoting scientific careers for girls. The methodology is adaptable to different educational levels, ages, and genders, and can be implemented in schools with limited resources. The approach not only contributes to scientific knowledge but also inspires the development of new scientists, promoting a solid and critical scientific education in new generations.

High-impact polystyrene (HIPS) nanocomposites containing organoclay were investigated under UV-accelerated aging using solid-state NMR to elucidate the evolution of molecular mobility and morphology. 13C CPMAS with variable contact time (VCT) and proton spin-lattice relaxation in the rotating frame (T₁ρH) sensitively captured the competition between chain scission and recombination across the nanocomposite films before and after exposure. The 1 wt% formulation predominantly displayed intercalated character with attenuated mobility changes upon aging, whereas 2-3 wt% systems showed heterogeneous and partially exfoliated morphologies with amplified mobility. While solid-state NMR does not directly detect microplastic particles, the relaxation signatures provide molecular-level evidence of fragmentation pathways with implications for potential microplastic formation.