Natura (Brazil)

ABSTRACTModelling the distribution of microendemic species presents significant challenges due to limited occurrence records and the coarse resolution of available bioclimatic data. This is particularly true for montane regions, which harbour high levels of endemism and environmental heterogeneity. In this study, we modelled the potential distribution of Brachycephalus pernix group toadlets to assess their range and identify key environmental drivers of their ecological niches. We applied two correlative modelling approaches—model‐selection procedures using MaxEnt and Ensemble Small Models—incorporating a broad suite of environmental predictors beyond traditional bioclimatic variables. Our results highlight that Ensemble Small Models outperformed model‐selection procedures (MaxEnt) in predicting suitable habitats for these microendemic species, yielding more spatially precise predictions centred in highland, montane and submontane regions. Suitability was strongly associated with environmental variables related to precipitation and moisture, which play a critical role in shaping the realised niche of the B. pernix group. The species exhibited niche conservatism, likely reflecting the retention of ancestral ecological preferences that facilitate persistence in montane environments. This supports the hypothesis that mountain ranges act as long‐term refugia during climatic fluctuations. Importantly, models incorporating heterogeneous environmental data outperformed those using only bioclimatic variables, highlighting the value of accounting for topographic and climatic complexity when modelling narrow‐range taxa. Despite identifying additional suitable habitats, many of these areas remain unprotected and are increasingly threatened by deforestation and land‐use change. Our findings provide new insights into the ecological requirements and distribution dynamics of the B. pernix group and emphasise the urgent need for targeted conservation efforts to safeguard their specialised habitats and ensure long‐term persistence.

Petroleum-derived conventional plastics play an importantrolein our lives despite their accumulation in the environment. An alternativeis natural polymers, in which starch has been highlighted. However,starch-derived films exhibit a low tensile strength. One way to improvethis is by adding zinc oxide nanoparticles (ZnO NPs). In this work,thermoplastic arrowroot starch/ZnO nanocomposite (TPA/ZnO NC) filmswere manufactured by solvent casting, and their thermal, tensile,morphological, and soil burial degradation properties were investigated.In addition, the TPA/ZnO NC films were evaluated for their suitabilityfor bread packaging. TEM confirmed the nanometer dimension for ZnO.XRD confirmed the formation of a thermoplastic material with characteristicpeaks of ZnO NPs, but characteristic bands for ZnO were not observedin the FTIR. SEM images showed that ZnO NP concentrations are randomlydistributed in the TPA matrix. The ZnO NPs did not cause major changesin the thermal degradation profile of the NC films in relation tothe starch matrix, as demonstrated by TGA results. TPA and TPA/ZnO-5films exhibited an improvement in tensile strength (0.62–1.44MPa) and modulus (1.73–10.46 MPa), respectively. ZnO NPs modifiedthe moisture, solubility, and transparency of the films. Our resultsdemonstrate that soil burial degradation for the films depends onthe soil moisture. Black and yellow spots, characteristic of fungalgrowth, were not observed on bread stored in the TPA/ZnO-3 and TPA/ZnO-5films. Our results indicate that TPA/ZnO-5 demonstrated a favorablecombination of σ, ε, and E and also exhibitedsoil burial degradation.

Diabetic foot ulcers present a significant clinical challenge because of their high prevalence and severe complications. The need for innovative and accessible treatment options is critical. Owing to their medicinal properties, natural products, such as geopropolis, hold promise. However, the wound healing potential of the geopropolis of Melipona fasciculata, particularly in accelerating the healing of diabetic ulcers, remains unexplored. In this study, we evaluated the ability of the geopropolis of M. fasciculata to promote wound healing in diabetic mice. Geopropolis was collected, prepared as a hydroalcoholic extract, and formulated into a topical cream. Non-obese diabetic (NOD) mice with induced chronic wounds were treated with this cream daily, and wound healing was assessed through macroscopic measurements, histological analysis, cytokine quantification, and in silico molecular docking studies. The results demonstrated that, compared with the control treatment, the geopropolis cream accelerated wound closure at all the analyzed time points (days 3, 7, and 14), reduced inflammatory infiltrates, and enhanced fibroblast proliferation and collagen deposition. These alterations were particularly pronounced in the final phase of healing, indicating an improvement in wound repair processes. These effects occurred without altering systemic cytokine levels, suggesting a localized treatment action. These results may be partially associated with the theoretical ability of beta-amyrin and cycloartenol to interact with human myeloperoxidase (MPO), as suggested by in silico docking analysis. Overall, the findings indicate that geopropolis cream could represent a viable alternative for managing diabetic ulcers, providing an effective means to enhance wound healing while remaining accessible to low-income populations.

A myriad of factors influence species interactions, and determining their relative importance is a major challenge in community ecology. Here, we explored the multiple factors influencing hummingbird visitation rates to flowers by considering pollinator and floral traits alongside the broader ecological context (i.e. phenology and floral abundance). Our data were collected from 32 systematically surveyed sites within native vegetation across three distinct Neotropical bioregions, each characterized by unique species composition and evolutionary histories. In total, we sampled 6423 flowering individuals, representing 404 plant species and 68 hummingbird species. At the community level, we found that hummingbirds primarily visit flowers with long, tubular corollas, aligning with predictions from pollination syndromes, and that visitation is also higher to flowers with straight corollas. At the species level, visitation frequency was associated with specific characteristics of the hummingbird species, such as its bill length and foraging behavior, where species often forage on flowers with matching morphological traits. Further, our findings extended beyond the expected trait preferences, revealing that visitation rates are also the outcome of the ecological context; particularly, the abundance of conspecific, but not heterospecific, flowers. The effect of conspecific abundance varied across bioregions, suggesting that from the plant perspective, intraspecific competition and facilitation could prevail in different regions. Additionally, we found that plant species whose floral morphology was more distinct from the other co‐flowering species tended to attract more visits, but only if they were abundant enough to stand out within the floral community. These findings highlight how plant and pollinator traits, modulated by the ecological context, jointly shape pollination dynamics.

This study explores the effects of a nutraceutical blend with prebiotics, β-glucans, essential minerals, and silymarin on gut microbiota, inflammation, and sleep quality in obesity through microbiota reshaping and metabolic improvements over 90 days. A double-blind, randomized trial was conducted on 77 participants divided into two groups receiving either a standard nutraceutical blend (NSupple) or a silymarin-enriched blend (NSupple_Silybum). Fecal and plasma samples were collected at baseline and post-supplementation for gut microbiota, metabolic, and inflammatory marker analysis. The results showed a reduction in body weight, waist-to-height ratio, total cholesterol, and fractions in the NSupple_Silybum group. There was a dysbiosis recovery shown by the increase in beneficial gut bacteria, such as Lentisphaerae phylum, Lactobacillus and Faecalibacterium genera, and Faecalibacterium prausnitzii in the NSupple group, with a concurrent reduction in Adlercreutzia and Sutterella in the NSupple_Silybum group. Both groups demonstrated improved inflammatory profiles by the reduced TNF-α/IL-10 ratio, reduced cortisol levels, and reduced Firmicutes/Bacteroides ratio. Additionally, improvements in sleep quality were associated with reductions in pro-inflammatory cytokines and improved microbiota composition. The nutraceutical blend reshaped gut microbiota, enhanced anti-inflammatory species, and improved metabolic and sleep parameters, highlighting its potential as a nutritional strategy for managing obesity and reducing inflammation.

Macapá City, located in the Brazilian Amazon, faces critical aquatic pollution challenges due to inadequate sanitation infrastructure, leading to metal contamination in fish within its urban water bodies. Our study evaluated the concentrations of metals (Cu, Cd, Cr, Fe, Mn, Ni, Pb, Zn, and Hg) in muscle tissues of fish from igarapés, ressaca areas, and canals. Samples were collected from six sampling sites to investigate the bioaccumulation of these metals and their potential human health risks. All metals were quantified by atomic absorption spectrometry, except Hg, which was quantified by inductively coupled plasma optical emission spectrometry. Metal concentrations were determined in three carnivorous and seven omnivorous fish species. Cd concentrations exceeded the Brazilian maximum limit established for human consumption in all fish species evaluated. The estimated daily intake (EDI) of Pb and Hg exceeded their reference doses. Our risk assessment, which combined the risk quotient (RQ) for individual metals and the risk index (RI) for metal mixtures, indicated health risks associated with the consumption of fish collected from the study areas. These results demonstrated a worrying exposure to metals (mainly Cd, Pb, and Hg), highlighting the need for environmental management measures and continuous monitoring to protect public health in vulnerable urban areas.

Aromatic plants are rich sources of essential oils (EOs), recognized for their therapeutic properties due to their diversity of phytochemicals. This study investigated the anxiolytic and antidepressant effects of Myrcia sylvatica essential oil (MsEO) through inhalation in an animal model and its in vitro anticholinesterase (AChE) activity. The EO was obtained by hydrodistillation, and its volatile constituents were analyzed by GC-MS. Swiss mice were exposed to doses of 0.1%, 1%, and 2% of the EO via an inhalation apparatus. The anxiolytic activity was assessed using the elevated plus maze and light-dark box tests, while antidepressant activity was evaluated using the tail suspension and forced swimming tests. To examine potential side effects, the animals were subjected to rotarod, Y-maze, and Morris water maze tests to assess motor coordination, memory, and learning. Anticholinesterase activity was determined by direct bioautography and colorimetry based on the Ellman method. The results demonstrated that inhalation of MsEO at doses of 0.1% and 1% significantly reduced anxiety and depressive-like behaviors without impairing memory, learning, or motor coordination in the animals. Moreover, MsEO inhibited acetylcholinesterase with an IC50 of 0.47 μg/mL. These findings suggest that MsEO has potential therapeutic applications for anxiety and depression disorders, with additional anticholinesterase activity warranting further investigation in cognitive-related conditions.

Abstract Lack of sufficient knowledge of biological diversity is the first barrier to promoting scientifically‐based conservation policies in Neotropical regions, where high diversity and limited sampling remains a challenge. We compiled fish occurrences data from the whole Upper Paraguay River basin (UPRB) and evaluated the altitudinal variation in species richness, local contribution to beta diversity (LCBD) and composition. We also evaluate the influence of other environmental variables on species richness. Occurrence of a total of 342 native and five exotic fish species were recorded. Fish species richness was higher in lower portions of the basin, with a clear decrease from 400 m.a.s.l. Richness was negatively correlated with altitude, and positively correlated with net primary productivity and slope. The LCBD presented higher values on floodplain and in headwaters. Intermediate classes presented greater relative importance, as they present greater relative richness in a small relative area in the basin. We observed a partial overlap in species composition along altitude classes. Three species classified in some category of threat according to the conservation status of ichthyofauna in Brazil have a limited spatial extent of occurrence, restricted within the Serra da Bodoquena plateau. The obtained results highlight the unique diversity in the floodplain–plateau continuum, therefore, choosing protected areas must consider altitude gradients in the UPRB. Given the small area of the conservation units in the basin, the important role of higher altitude streams in regional fish species diversity and the several threats in the plateau, we conclude that an increase in conservation effort is needed in the plateau portion of the Upper Paraguay River basin.

O estudo analisa a evolução temporal na taxa e nos anos potenciais de vida perdidos (APVP) por homicídios ocorridos no estado de Roraima de 2000 a 2020, sendo um estudo ecológico e de tendência temporal. A população compreendeu o total de óbitos por agressão obtidos do Sistema de Informação sobre Mortalidade. As taxas de homicídios e os APVP (variáveis dependentes) foram analisadas em função do ano (variável independente), usando modelos de regressão estimados por Mínimos Quadrados Generalizados (GLS). O modelo foi considerado significativo, com p≤0,05. Foi identificada a presença de tendência nas séries como crescente ou decrescente, conforme o sentido da reta. O valor do coeficiente de determinação foi utilizado como medida de ajuste. As taxas de homicídios total, do sexo masculino, das faixas etárias de 10 a 19 anos, 20 a 29 anos, de 30 a 59 anos, os APVP total e os APVP do sexo masculino apresentaram a tendência temporal de redução entre os anos de 2000 e 2010 e aumento entre os anos de 2011 e 2020. As taxas de homicídios do sexo feminino, da faixa etária de 0 a 9 anos, e dos APVP do sexo feminino apresentaram tendência temporal crescente linear. A faixa etária de 60 anos e mais não apresentou evidência de tendência temporal estatisticamente significativa. Além disso, as taxas de homicídios total são muito superiores ao nível epidêmico da Organização Mundial da Saúde de 10 homicídios por 100 mil habitantes. O homicídio é um importante problema de segurança e de saúde pública, além de histórico e cultural no estado de Roraima. Todas as taxas de homicídios encontram-se em aumento na última década, estão acima da média nacional, são consideradas epidêmicas, e os APVP mostraram que muitas vidas foram perdidas precocemente.