Search Results (117)

Stable oxygen isotopes (δ¹⁸O) in wood provide integrative records of plant water use and regional hydroclimatic processes, offering a powerful framework for spatial ecological analysis in tropical forests. Here, we present the first regional-scale δ¹⁸O isoscapes for Amazonian wood based on 387 trees sampled across 25 sites. After α-cellulose extraction, δ¹⁸O values were modeled using multiple linear regression (MLR) and Random Forest (RF) approaches. A Moran’s I test revealed no significant spatial autocorrelation (p = 0.73), indicating that geostatistical interpolation methods such as kriging were not appropriate for this dataset. The MLR model based on site-average data achieved an R² of 0.70, with a mean absolute error (MAE) of 0.56‰ and root mean square error (RMSE) of 0.68‰. The RF model showed comparable performance (R² = 0.67; MAE = 0.64‰; RMSE = 0.77‰). Both approaches reproduced a coherent southeast-to-northwest gradient, with lower δ¹⁸O values in the western Amazon and higher values in the east, consistent with regional patterns in precipitation isotopic composition and evapotranspiration. These findings demonstrate that climate-driven statistical modeling effectively captures large-scale isotopic structure across the Amazon basin, providing a robust spatial representation of δ¹⁸O variability in tropical forest wood. Full article

The Western Amazon is a global biodiversity hotspot, yet the Upper Napo River Basin (UNRB) remains understudied regarding aquatic ecosystem health along anthropogenic gradients. We integrated benthic macroinvertebrate assemblages with physicochemical and microbiological indicators across 45 sites to assess ecological quality under four impact scenarios: Few Threats (FT, reference sites; n = 6), Crop/Aquaculture (CA; n = 22), Gold Mining (GM; n = 10), and Wastewater Discharge (WD; n = 7). Analysis of 2285 individuals (62 families) revealed clear degradation across the anthropogenic gradient. Reference sites (FT) exhibited high integrity (q₀ = 24.3 families), establishing the regional baseline for Andean–Amazonian freshwater ecosystems. In stark contrast, GM sites showed catastrophic defaunation (q₀ = 9.9 families) coupled with extreme turbidity (1320 ± 1589 NTU) and heavy metal mobilization (Fe: 430 ± 229 µg/L; Cu: 338 ± 128 µg/L), placing these reaches in “Bad” ecological status (Ecological Quality Ratio, EQR ≤ 0.16). Wastewater sites reached critical fecal coliform levels (33,708 ± 58,047 CFU/100 mL)—165-fold higher than FT sites—indicating severe sanitary impairment and community collapse (EQR = 0.28, dominated by Chironomidae at 80%). The application of ASPT (Average Score Per Taxon) and EQR proved essential for detecting functional shifts toward tolerant assemblages even when raw biotic scores appeared moderate. Crop/Aquaculture sites showed intermediate degradation (EQR = 0.37–0.38), reflecting chronic pesticide exposure and habitat loss. We conclude that gold mining and wastewater discharge are the primary drivers pushing the UNRB toward ecological collapse, with GM exerting the most severe impact on aquatic biodiversity. Safeguarding this global freshwater stronghold requires immediate implementation of multimetric biomonitoring, enhanced mining regulation, wastewater treatment infrastructure, and establishment of Indigenous-led fluvial reserves to maintain long-term connectivity. Full article

Lippia origanoides Kunth (Verbenaceae family), popularly known in northern Brazil as “Salva-de-Marajó”, is a native plant widely used in traditional medicine and cooking. While previous studies have addressed its antimicrobial and insecticidal properties, its ability to inhibit disease-related enzymes has received limited attention. This study investigated the essential oil (EO) of L. origanoides as a source of enzyme inhibitors relevant to Alzheimer’s disease, metabolic disorders and skin pigmentation disorders. The EO showed strong inhibitory activity against acetylcholinesterase (IC₅₀: 22.9 μg/mL) and α-glucosidase (IC₅₀: 14.6 μg/mL), indicating potential for managing neurodegenerative conditions and diabetes, respectively. Moderate inhibition was observed for lipase, butyrylcholinesterase and tyrosinase. Although carvacrol, the major EO constituent, contributed significantly to these effects, it did not fully explain the observed bioactivity. Bio-guided fractionation revealed that oxygenated compounds were mainly responsible for inhibiting cholinesterases and lipase, whereas α-glucosidase inhibition was associated with hydrocarbon compounds. Both fractions contributed to tyrosinase inhibition, reinforcing the EO’s relevance for treating hyperpigmentation. Furthermore, the EO demonstrated strong antioxidant activity, largely linked to carvacrol and oxygenated constituents. Chemical characterization by GC-MS, GC-FID and enantiomeric analysis strengthened the relationship between composition and bioactivity. Overall, L. origanoides EO emerged as a promising multifunctional natural product for therapeutic and cosmetic applications. Full article

Cryphalus dilutus is an emerging invasive pest of tropical and subtropical regions, with Mangifera indica and Ficus carica being its primary host plants. Larval damage caused by this insect can lead to severe tree wilting, posing a direct threat to agricultural production and ecological security. Native to South Asia, C. dilutus has established introduced populations in the Near East, Mexico, and other areas. In recent years, it has invaded multiple regions, including southern China and southern Italy. Given the widespread global distribution of host plants and the intensification of climate change, their distribution ranges are expected to expand. However, research assessing the potential global geographical distribution of this pest under climate change is lacking. In this study, we used the Random Forest model to predict the potential distribution range of C. dilutus. Under historical climatic conditions between 1970 and 2000, suitable climatic regions for C. dilutus were primarily distributed across southern China, southeastern Brazil, southeastern Mexico, the Congo Basin periphery, and the Iberian Peninsula, with a total area of 12,192.42 × 10⁴ km². The Temperature Annual Range and Precipitation of Warmest Quarter were identified as key environmental determinants that shaped its distribution. Under the future RCP4.5 climate scenario projected for the 2050s, the total suitable area for C. dilutus is projected to contract. Specifically, high-, medium-, and low-suitability areas are projected to decline by 52.77%, 62.39%, and 24.02%, respectively. While the total area of the very low zones is expected to increase, the total area of the suitable region has been reduced to 11,891.17 ×10⁴ km². Future climate change is expected to drive the distribution northward to high-altitude areas and inland areas. Model projections indicate a poleward expansion of the fundamental climatic niche, with climatic suitability increasing in high-latitude and high-altitude regions, such as Northern Europe and western North America. Conversely, current core tropical habitats in the Indian subcontinent and the Amazon Basin are projected to face significant habitat degradation due to thermal stress. Agricultural regions previously considered relatively safe due to climatic constraints, such as northern China, the midwestern United States, and Eastern Europe, may face new challenges from pest infestation. These findings underscore the importance of proactive monitoring and implementation of preventive measures. This provides crucial decision support for countries and regions to formulate precise pest control strategies and offers a theoretical basis for early monitoring and prevention of cross-border invasions on a global scale. Full article

Palynological analysis of seventy-seven cutting samples from six boreholes in the Marañón Basin (northeastern Peru) has identified five distinct Neogene marine incursion events (ME-1 to ME-5), challenging existing models that depict them as short-lived episodes. The diverse palynological assemblages, comprising spores, pollen, freshwater algae, and critical marine indicators—including dinoflagellate cysts, foraminiferal test linings, and copepod eggs—reveal that these incursions were protracted and recurrent, each associated with a maximum flooding surface and bounded by intervals of continental sedimentation. The stratigraphic record shows the earliest event ME-1 (Aquitanian to Late Burdigalian, 23.03–17.7 Ma) identified across all studied wells. ME-2 (latest Burdigalian to Middle Langhian, 17.0–16.1 Ma) is also recorded basin-wide. ME-3 (latest Burdigalian to earliest Langhian 16.5–15.7 Ma) registered in two wells. ME-4 (Late Langhian to latest Serravallian, 14.6–11.62 Ma) registered in only two wells and ME-5 (Early Tortonian, 11.6–10 Ma) is documented exclusively in the southernmost well, culminating in Zanclean (~5.5–3.6 Ma) mangrove development. We interpret the ingress routes for ME-1 to ME-3 to be westward via the Marañón Portal or northward from the Caribbean, associating them with the Proto-Pebas and Pebas systems. In contrast, ME-4 would also be from Amazon trunk or Paraná Portal associated with the Pebas Phase, and ME-5 likely originated from the south through the Paraná Portal, linking it to the Acre Phase. These results demonstrate that Miocene marine incursions into western Amazonia were not brief episodes but represented prolonged periods of marine influence, facilitated by sustained subsidence in the Marañón retro-arc foreland basin. This history reveals a dynamic connectivity throughout the Neogene, with marine conditions acting as persistent biogeographic barriers that critically shaped the region’s Miocene biodiversity patterns. This refined chronology provides a comprehensive regional framework, significantly advancing our understanding of Amazonian paleogeography. Full article

Anthropogenic pressures in the Amazon Basin are reshaping human–animal–environment interactions and increasing zoonotic disease risk. Within this One Health context, domestic dogs and cats are underrecognized contributors to pathogen circulation at the human–wildlife interface. We conducted a PRISMA-compliant systematic review of zoonotic pathogens reported in companion animals across Amazonian territories in nine countries, including literature published between 2000 and 2025 in four languages. Zoonotic pathogens showed a heterogeneous yet widespread distribution, with parasitic infections, particularly Leishmania spp., Toxoplasma gondii, and vector-borne protozoa, being the most frequently reported. A pronounced geographic bias was evident, with studies concentrated in Brazil and selected areas of the western Amazon, while large portions of the Basin remain understudied. Methodological limitations included reliance on cross-sectional designs and heterogeneous diagnostic approaches, often based solely on serology. These findings highlight the need to strengthen One Health-oriented governance frameworks that integrate animal health surveillance into environmental and public health policies. Priority actions include expanding surveillance to underrepresented regions, harmonizing diagnostic protocols, investing in regional laboratory capacity, and promoting community-based monitoring. Strengthened cross-sectoral and transboundary coordination is essential to reduce zoonotic risk and support evidence-based disease prevention in Amazonian ecosystems. Full article

This study aimed to test the factorial structure of the Eating Motivation Survey (TEMS) using Confirmatory Factor Analysis (CFA) in a sample of 632 university students from the Western Brazilian Amazon. A cross-sectional study was conducted between December 2022 and April 2023 with participants of both sexes, aged 18 or older. In addition to CFA, psychometric analyses were performed, and a Structural Equation Model was developed to examine the relationships between individual characteristics (age, sex, and Body Mass Index (BMI)) and the TEMS constructs. The results showed that 58.3% of participants were female, with a mean age of 25.29 years. The CFA supported an eight-factor model (health, natural concerns, socialization, price, visual appeal, weight control, emotional control, and social image) with 24 items, presenting good validity and reliability indices. Older individuals and those with lower BMIs prioritized health, natural concerns, and weight control, while younger participants, women, and those with higher BMIs were more influenced by emotional control. The findings contribute to understanding eating motivations in culturally diverse contexts and may support strategies aimed at promoting healthier dietary behaviors and preventing diet-related chronic diseases. Full article

The pacarana (Dinomys branickii) is a typical rodent of the Amazonian biome crepuscular habits, feeding on fruits, leaves, and roots. However, studies on these animals, inhabiting behaviors, and their parasites are limited. This study aimed to report the parasites found in fecal samples and a dead specimen of D. branickii in the Brazilian Cerrado. In 2023, fecal samples from five animals were collected and examined using flotation and simple sedimentation techniques for the identification of parasitic eggs. In 2025, a necropsy was performed on a decreased animal. Fecal samples of all animals were positive for eggs of Strongyloides spp., with two cases of co-infection with Oxyuroidea eggs and one with Trichuris sp. eggs. The Wellcomia branickii found during necropsy is a specific helminth of the pacaranas gastrointestinal tract. The natural geographical range of D. branickii is in the Western Amazon. Its introduction in the Cerrado, although for conservation purposes, reinforces the potential for this translocated species to disseminate non-native parasites outside its natural range. Full article

This study investigates hydroid species distribution across the western Atlantic coastline, focusing on biogeographic patterns, comparing them with Caribbean assemblages, and assess the influence of environmental variables—including salinity, temperature, primary productivity, ocean currents, and chlorophyll—on biogeographic structure. We analyzed 375 species from to 9259 records (1946–2022), spanning the western Atlantic from the Caribbean to southern Argentina (28° N–53° S). Cluster analyses using UPGMA and ordination via nMDS, based on Sorensen-transformed occurrence data. Taxonomic distinctness was assessed with Average Taxonomic Distinctness (Delta+) and Lambda+ variation. UPGMA clustering revealed two main groups: one in the Caribbean and Brazil, and another in southern Brazil, Uruguay, and Argentina. The Amazon River mouth acted as a semi-permeable barrier, with 21.4% species overlap between Caribbean and Brazil. Southeastern Brazil had the highest species richness, likely due to environmental synergy and biodiversity hotspot. Assemblages followed known biogeographic gradients, with lower diversity offshore and on islands. The Río de la Plata showed a distinct, salinity-driven composition. Salinity, chlorophyll, and currents were key distribution drivers. Full article

Given the reduced resilience of the Amazon rainforest due to deforestation, identifying high-quality genetic markers for the propagation of native species is crucial for forest regeneration. This study investigated metabolic dynamics during Brazil nut (Bertholletia excelsa) germination to identify biochemical markers for selecting superior genotypes. We analyzed primary reserves (carbohydrates, lipids, proteins) and minerals in two genotypes, 606 and Santa Fé, in seven germination stages. Our results revealed distinct metabolic patterns. Genotype 606 showed 101.73% greater efficiency in the transient accumulation of starch, 34.86% higher degradation of lipids, and 34.86% higher transitory synthesis of soluble proteins. Conversely, Santa Fé was 16.8% more efficient in amino acid synthesis and 795.33% in boron compartmentalization, though less so in sucrose (2.17%) and in lipid synthesis (24.84%). Overall, early germination stages involved starch, sucrose degradation and mineral consumption. During post-germinative stages, protein and lipid degradation likely fueled gluconeogenic pathways and supported carbohydrate synthesis and seedling growth. This work increases the knowledge on Brazil nut germination physiology and identifies metabolic markers that differentiate genotypes. These findings are fundamental for our understanding of primary metabolism turnover in B. excelsa and provide a basis to support forest restoration and genetic improvement programs. In addition, we hope to contribute to the selection of superior high-performance genotypes, which are essential for recovering degraded areas and enhancing productive plantations in the Amazon region. Full article

Research on Mesoscale Convective Systems (MCSs) in Ecuador has focused on regional studies. However, it lacks a thorough and general examination of their relationship with the nation’s diverse orography and large-scale phenomena. This study conducts a climatological analysis of MCS occurrence throughout Ecuador’s natural regions. We perform this study using Sen’s Slope and the Mann–Kendall test. Teleconnections from the Pacific and Atlantic Oceans are studied through wavelet decomposition between time series and Pacific and Atlantic oceanic indices. The main factors that control MCS formation depend on the region. The Intertropical Convergence Zone (ITCZ) at the large scale affects the entire territory. In western Ecuador, MCS formation is mostly related to the El Niño current and the Chocó Low-Level Jet (CLLJ). The Orinoco Low-Level Jet (OLLJ) and evapotranspiration and nocturnal convection display the largest roles in the east. A progressive intensification of activity from Highlands-North in SON is detected (0.143 MCSs per year). MCSs contribute 26% of total precipitation on average, with regional variations from Coast-South (16.41%) to Amazon-North (44.13%). The research confirms existing knowledge about El Niño’s strong relationship (ρ = 0.7) with MCS occurrence in coastal areas while uncovering new complex patterns. The Trans-Nino Index (TNI) functions as a critical two-sided modulator that conventional analysis methods fail to detect. It produces null correlations over conventional time series of MCS occurrence yet emerges as a primary driver of low-frequency variability in the proposed six natural zones of Ecuador. Wavelet decomposition reveals contrasting TNI responses: Amazon-North shows positive correlation (0.73) while Amazon-South exhibits negative correlation (−0.70) at low frequencies. This affects Walker circulations dynamics over the Pacific Ocean. This research establishes fundamental knowledge about MCSs in Ecuador. It builds on a database with strong methodology as a backbone. The research provides essential information about the factors leading to convection in the country. This will help improve seasonal forecast accuracy and risk management effectiveness. Full article

In the native açaí groves of Lago do Maicá, in western Pará, harvesting is still performed using traditional techniques such as the peconha, which is a rope device tied to the feet that helps with climbing açaí palms. The absence of affordable and locally adaptable technologies compromises the safety of extractivists and limits the strengthening of the açaí value chain, affecting the development of a forest-based bioeconomy. This study focused on the Quilombo of Murumuru to understand the profile of local extractivists and identify which technologies could be more easily adopted in floodplain environments. After ethics approval, fieldwork involved participatory activities including knowledge-sharing meetings, transect walks, community discussions, and structured interviews. The results indicated that most collectors identify themselves primarily as açaí extractivists. Some rely exclusively on this activity for income, while others complement it with fishing or agro-extractivism. Reports of occupational risks were frequent, especially due to falls and contact with venomous animals. There was also a clear lack of technical assistance and limited access to context-sensitive technologies. The study highlights the need for institutional partnerships that support income diversification, value traditional knowledge, and improve working conditions. Strengthening the native açaí value chain in floodplain regions is essential for reducing socioeconomic vulnerability and advancing a regenerative, community-centered bioeconomy in the Amazon. Full article

Background/Objectives: Toxoplasma gondii, an obligate intracellular parasite, poses a major global health concern owing to its potential for congenital transmission, particularly during pregnancy. Current pharmacological treatments, including spiramycin and pyrimethamine, exhibit limitations in both efficacy and safety, underscoring the need for novel therapeutic strategies. In this study, we investigated the antiparasitic potential of BthTX-II, an Asp49 phospholipase A₂ (PLA₂) isolated from Bothrops jararacussu venom, in human trophoblast cells (BeWo) and third-trimester human placental explants infected with T. gondii. Methods: In vitro assays were performed using BeWo cells infected with T. gondii tachyzoites and treated with non-cytotoxic concentrations of BthTX-II (3.125, 1.56, and 0.78 µg/mL). An ex vivo model employing third-trimester human placental villous explants was used under similar conditions. Parasite proliferation, adhesion, and invasion were assessed alongside host immune response modulation. Results: Our findings demonstrate that BthTX-II reduces T. gondii proliferation in BeWo cells at all tested non-cytotoxic concentrations. The toxin also significantly impaired parasite adhesion and invasion while modulating host immune response by upregulating interleukin (IL)-6, IL-8, and macrophage migration inhibitory factor (MIF), and downregulating vascular endothelial growth factor—potentially disrupting parasite proliferation. In placental villous explants, BthTX-II (1.56 μg/mL) reduced T. gondii proliferation and modulated IL-8, MIF, and tumour necrosis factor-alpha levels without compromising tissue viability. Conclusions: These findings highlight BthTX-II as a potential candidate in toxoplasmosis treatment. Further investigation should focus on its dual role in limiting parasite development and modulating immune responses at the maternal–fetal interface. Full article

Trace metal pollution in tropical freshwater ecosystems poses growing public health concerns, particularly in regions where fisheries are central to food security; however, little is known about metal exposure risks in the Western Amazon. This study presents the first assessment of trace metal concentrations in fish sold at the main market in El Coca, a rapidly growing city in the Ecuadorian Amazon. We analyzed 11 trace metals in 17 commercially important species and estimated seven health risk indices based on two fish consumption scenarios and international reference dose standards. Our results show that all species exceeded recommended thresholds for arsenic, mercury, and lead, while one species surpassed guidelines for aluminum. Metal concentrations varied by species and river of origin: small catfish from the Payamino River had elevated cadmium, chromium, copper, and manganese levels, potentially linked to upstream gold mining, whereas larger catfish showed higher mercury and arsenic accumulation. Monte Carlo simulations of risk indices suggested overall some disease risk, but the lack of local demographic data limits accurate assessments for vulnerable groups. Despite sampling limitations, our findings offer the first baseline for monitoring trace metal exposure in the northern Ecuadorian Amazon and underscore the need for targeted public health strategies in this understudied region. Full article

Euterpe precatoria Mart. is an increasingly important palm for subsistence and income generation in central and western Amazonia with growing demand for its fruit pulp, which is an alternative source of açaí juice for domestic and international markets. This study synthesizes current knowledge on its systematics, ecology, fruit production in natural populations, fruit quality, uses, population management, and related areas, identifying critical research gaps. A systematic literature survey was conducted across databases including Web of Science, Scopus, Scielo, CAPES, and Embrapa. Of 1568 studies referencing Euterpe, 273 focused on E. precatoria, with 90 addressing priority themes. Genetic diversity studies suggest the E. precatoria may represent a complex of species. Its population abundance varies across habitats: the highest variability occurs in terra firme, followed by baixios and várzeas. Várzeas exhibit greater productivity potential, with more bunches per plant and higher fruit weight than baixios; no production data exist for terra firme. Additionally, E. precatoria has higher anthocyanin content than E. oleracea, the primary commercial açaí species. Management of natural populations and cultivation practices are essential for sustainable production; however, studies in these fields are still limited. The information is crucial to inform strategies aiming to promote the sustainable production of the species. Full article