Search Results (77)

Hematological and blood biochemical parameters are useful tools for monitoring fish physiological status; however, information on their variation between sexes during reproductive development remains limited for Colossoma macropomum. This study evaluated the hematological and blood biochemical profiles of male and female C. macropomum during growth and first sexual maturation under controlled conditions in a recirculating aquaculture system. Fish were sampled at seven ages from 590 to 1080 days after hatching (DAH). Hematocrit, total plasma protein, hemoglobin, leukocytes, erythrocytes, glucose, cholesterol, and triglycerides were evaluated, and reproductive development was assessed through macroscopic and histological examination of the gonads. Age significantly affected hematocrit, leukocytes, erythrocytes, glucose, triglycerides, cholesterol, and total plasma protein, whereas hemoglobin remained unchanged. Sex significantly affected only glucose, with females showing higher concentrations than males across ages. A significant sex × age interaction was detected only for total plasma protein, with higher concentrations in females than males at 1080 DAH. These findings indicate that developmental progression associated with age is a major source of variation in blood profiles, whereas sex-related effects are limited and parameter-specific. The results provide baseline physiological information for monitoring C. macropomum broodstock under controlled conditions. Full article

Controlling the arbovirus vector Aedes aegypti represents a growing public health challange, intensifying the search for alternatives to combat the mosquito. In this context, the present study aims to evaluate the larvicidal activity of essential oils from three Piper species and their mixtures, as well as their preliminary toxicity and in silico acetylcholinesterase (AChE) inhibitory potential. The essential oils and mixtures were characterized by GC–MS. The larvicidal activity test was performed against third-stage larvae, and a preliminary toxicity test was preformed against Artemia salina. The results showed that the oils had a high content of phenylpropanoids such as safrole, dillapiole, and eugenol, as well as their derivatives. The mixtures showed lower toxicity when compared to the pure oils. P. aduncum oil showed the highest larvicidal action (LC₅₀ = 26.2 µg/mL), followed by P. callosum (LC₅₀ = 53.2 µg/mL), while P. divaricatum had the lowest activity (LC₅₀ = 123.8 µg/mL). Among the mixtures, the combination of P. divaricatum and P. aduncum stood out for its synergistic effect. Molecular docking analyses suggested that phytoconstituents interact favorably with AChE, supporting a neurotoxic mechanism associated with enzyme inhibition. Thus, Piper essential oils and mixtures are promising alternatives for the control of A. aegypti. Full article

In transitional tropical ecosystems such as the Amazonia–Cerrado ecotone, dominant tree species experience strong environmental heterogeneity, requiring coordinated functional strategies to cope with drought, nutrient limitation, and disturbance. However, how these species integrate leaf morphoanatomical traits and wood density to persist in such environments remains poorly understood. We assessed the coordination among leaf anatomical and morphological traits and their relationship with wood density in five dominant tree species across three savanna park sites in the Amazonia–Cerrado transition. Morphological traits included leaf thickness, specific leaf area, leaf dry matter content, and wood density, alongside 17 anatomical leaf traits. We analyzed inter- and intraspecific variation and covariation patterns to identify trait-based ecological strategies along the acquisitive–conservative spectrum. We found strong coordination among traits related to protection (e.g., cuticle thickness and trichomes) and resource use, as well as clear alignment between leaf and wood traits. Species identity explained most trait variation, although leaf thickness showed notable intraspecific plasticity. Species with conservative traits exhibited thicker leaves and higher wood density, whereas species with acquisitive strategy showed higher specific leaf area and lower leaf dry matter content. Overall, trait coordination reflects integrated ecological strategies shaped by environmental heterogeneity, highlighting the role of multi-trait syndromes in driving functional adaptation in ecotonal systems. Full article

A new species, Anthurium elsieae, from the Amapá State Forest in the Eastern Brazilian Amazon is described and illustrated. Belonging to the Anthurium sect. Schizoplacium, the species differs from its Amazonian congeners, A. pentaphyllum and A. eminens, by a unique combination of morphological characters, including a short petiole (10–13 cm), inconspicuous venation with a marginal collective vein, and a notably short spadix (ca. 1.7 cm long). Detailed morphological descriptions, habitat information, and diagnostic features are provided. The species appears to be narrowly distributed, occurring at approximately 30 m elevation in terra firme forest. An identification key to the species of Anthurium sect. Schizoplacium is also presented. The discovery of this species highlights the relevance of continued taxonomic and floristic efforts for improving biodiversity knowledge in the Amazon domain and supporting conservation planning. Full article

Mosquitoes are recognized as the arthropod group with the greatest vectorial capacity, and the viruses they transmit constitute a significant concern in the context of global One Health. In addition, these insects act as hosts for a wide diversity of insect-specific viruses (ISVs), which exclusively infect arthropods. Expanding knowledge of ISVs is particularly relevant, given their potential influence on arbovirus replication and their role in elucidating the evolutionary processes that shape virus–vector interactions. In this study, we report the isolation and molecular analysis of three negeviruses associated with different mosquito species of the genera Culex, Coquillettidia, Mansonia, and Ochlerotatus, collected in Belém, Pará State, in the Brazilian Amazon: Loreto virus, Wallerfield virus, and a putative new species, designated Terra firme virus. Eleven pools exhibited cellular alterations consistent with cytopathic effects in invertebrate C6/36 cells but showed no evidence of replication in vertebrate Vero cells. Notably, simultaneous infections by two or three negeviruses were detected in some mosquito pools, indicating the occurrence of multiple viral infections within individual samples. Genomic analyses revealed that the isolated strains share conserved domains with previously described isolates from other countries. Phylogenetic inferences demonstrated that the investigated strains are classified within the clades Nelorpivirus and Sandewavirus. Taken together, these findings expand the currently known diversity of the negevirus group and contribute to a more comprehensive understanding of its host range and geographic distribution. Full article

The Amazon Forest harbors one of the largest fungal diversities on the planet, occupying a wide variety of ecological niches comprising terra firme (non-flooded forest), várzea (white-water floodplains), and igapó (black-water floodplains). In this review article, we examine Amazonian fungal diversity based on three complementary approaches—culture-based surveys, in situ inventories of macrofungi, and environmental DNA/metagenomic analyses—discussing advances, limitations, and contributions to regional mycological knowledge. Subsequently, we present a critical synthesis of the potential of Amazonian basidiomycetes regarding the production of metabolites with antimicrobial activity, highlighting the main genera reported in the literature, the chemical classes involved (e.g., terpenes, steroids, quinones, and bioactive peptides), and the metabolic pathways responsible for their biosynthesis. The integration between biodiversity and bioprospecting underscores the importance of Amazonian fungi both for understanding ecological processes and for the development of new solutions to the antimicrobial resistance challenge. This work seeks to fill current gaps in the academic literature and to contribute to future strategies for the conservation and sustainable use of regional mycobiota. Full article

Black pepper (Piper nigrum L.) is an important crop in Pará, Brazil; however, irrigation management remains one of the main constraints to achieving stable productivity and high essential oil yield. By determining soil water tension for rational irrigation management that ensures high agronomic performance of black pepper, it is possible to optimize irrigation water use efficiency through monitoring critical soil moisture with the aid of tensiometers. This study evaluated yield, water use efficiency (WUE) and essential oil yield of two black pepper genotypes under five soil water tensions (15–55 kPa) using a split-plot experimental design. The Uthirankotta genotype showed higher yield and WUE, reaching maximum values at 35 kPa, whereas the highest essential oil extraction yield occurred at 15 kPa. Positive correlations were observed between essential oil yield and the main productive traits. Therefore, cultivation of the Uthirankotta genotype under tensiometer-based irrigation management is recommended under the edaphoclimatic conditions of Pará, using a critical tension of 35 kPa as a reference to increase productivity and optimize irrigation water use efficiency, considering the differential genotype response to irrigation management under humid tropical conditions. Full article

Identifying the diversity of wildlife hosts for malaria parasites in wildlife is crucial for understanding transmission dynamics in endemic regions where humans, vectors, and wildlife heavily overlap. We examined the presence of Plasmodium parasites in free-ranging ring-tailed coatis (Nasua nasua, n = 44) and nine-banded armadillos (Dasypus novemcinctus, n = 66) from an Indigenous community in the Peruvian Amazon. Nested PCR targeting the mitochondrial cytb gene detected Plasmodium spp. DNA in two coatis (4.7%). Sequencing revealed one lineage identical to Plasmodium vivax/P. simium and another to P. malariae/P. brasilianum. A subset of samples was reanalyzed using cox3-based PCR and sequencing in an independent laboratory, confirming P. malariae/P. brasilianum in one coati. No infections were observed in armadillos. These results indicate that coatis in the wild may host diverse Plasmodiidae parasites and that coatis may even carry Plasmodium spp., likely as incidental hosts. Expanding surveillance to additional non-primate mammals will help clarify their role in sylvatic malaria ecology and evaluate potential zoonotic risks. 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

Tropical forests continue to experience high levels of habitat loss and degradation, with wildfires becoming a frequent component of human-modified landscapes. Here we investigate the response of palm species to the conversion of old-growth forests to successional mosaics, including forest patches burned during wildfires. Palms (≥50 cm height) were recorded once in 2023–2024, across four habitat classes: terra firme old-growth stands, regenerating forest stands associated with slash-and-burn agriculture, old-growth stands burned once and twice, and active cassava fields, in the Tapajós-Arapiuns Extractive Reserve, in the eastern Brazilian Amazon. The flammability of palm leaf litter and forest litter were also examined to assess the potential connections between palm proliferation and wildfires. A total of 10 palm species were recorded in this social forest (including slash-and-burn agriculture and resulting successional mosaics), with positive, negative, and neutral responses to land use. Species richness did not differ among forest habitats, but absolute palm abundance was greatest in disturbed habitats. Only Attalea spectabilis Mart. (curuá) exhibited increased relative abundance across disturbed habitats, including active cassava field. Attalea spectabilis accounted for almost 43% of all stems in the old-growth forest, 89% in regenerating forests, 90% in burned forests, and 79% in crop fields. Disturbed habitats supported a five-to-ten-fold increment in curuá leaves as a measure of habitat flammability. Although curuá litter exhibited lower flame temperature and height, its lower carbon and higher volatile content is expected to be more sensitive to fire ignition and promote the spread of wildfires. The conversion of old-growth forests into social forests promotes the establishment of palm-dominated forests, increasing the potential for a forest transition further fueled by wildfires, with effects on forest resilience and social reproduction still to be understood. Full article

Bats, as key ecological players, interact with a diverse array of organisms and perform essential roles in ecosystems, including pollination, pest control, and seed dispersal. However, their populations face significant threats from habitat contamination, particularly from microplastics (MPs). This study introduces a novel, efficient, and cost-effective method for visualizing transparent microplastics using ultraviolet (UV) light. By employing handheld UV flashlights with a wavelength range of 312 to 400 nm, we enhance the detection of MPs that may otherwise go unnoticed due to color overlap with filtration membranes. All necessary precautions were taken during sampling and analysis to minimize the risk of contamination and ensure the reliability of the results. Our findings demonstrate that the application of UV light significantly improves the visualization and identification of MPs, particularly transparent fibers. This innovative approach contributes to our understanding of plastic contamination in bat habitats and underscores the importance of monitoring environmental pollutants to protect bat populations and maintain ecosystem health. Full article

Environmental variability modifies forest structure through interactions among soil properties, topography, and climate. These factors influence the occurrence of contrasting forest types in northern Amazonia (Brazil), such as forests in highlands (Terra Firme) and forests under regular flooding (Várzea). Flooding regimes influence soil formation and modify soil geochemistry, nutrient distribution, and organic matter accumulation, shaping forest structure and composition. The objective was to determine the relationships between structure and soil characteristics in non-flooded and flooded tropical forests. We compared forest structure and soil characteristics at both conditions (n = 2 treatments × 20 replicas = 40 plots) using univariate and multivariate analyses. We found significant differences in most of the studied variables between forest types, both chemical and physical properties. Our results showed that flooding defines forest structure and composition (e.g., tree density, height, and volume) and influences soil nutrient characteristics. Floodplain forests exhibited higher soil nutrient concentration and organic carbon content, likely due to periodic litter accumulation, sediments, and reduced decomposition rates. In contrast, non-flooded forests were characterized by lower nutrient levels, higher sand content, and greater forest structure values (e.g., height, basal area, and volume). These insights contribute to understanding the functioning of both forest ecosystems. Full article

cangas are iron-rich outcrops where rupestrian fields develop in the Carajás Mountain Range (CMR). canga formations are ancient ecosystems characterized by high levels of endemic and threatened plant species that thrive on iron-rich substrates in the southeastern Amazon uplands. The recent taxonomic validation of these species enables more accurate distribution modeling across past, present, and future time scales. This work presents a comprehensive palynological database for the Amazon canga vegetation, resulting from extensive field and herbarium surveys, as well as the compilation and taxonomic validation of species in the Carajás Mountain Range (CMR). This atlas includes 204 plant species: 10 ferns and lycophytes, 62 monocots, and 132 eudicots and magnoliids (mainly herbs, lianas, and trees). Most flowering plants are pollinated by bees, with secondary pollination by other insects and wind. The taxa co-occur in two geoenvironments: (1) forested slopes and caves over plinthosols and ferralsols and (2) slopes with canga vegetation over plinthosols. Seventeen species are potential domesticates used by Indigenous peoples. This highlights canga vegetation as a unique and diverse ecosystem with various survival strategies, emphasizing the need for precise habitat definitions in paleoenvironmental and paleoclimate reconstructions. This atlas provides a valuable reference for palynological studies, enhancing the vegetation reconstruction, climate history analysis, pre-Columbian influences on vegetation patterns, and ecological monitoring. Full article

Macrofungi are key decomposers of organic matter and play an active role in biogeochemical cycles, thereby contributing to carbon sequestration in forest ecosystems. Floodplain forests (várzeas) are characterized by the dynamics of rising and receding waters, which are rich in suspended material and influence species variation and adaptation. The knowledge about the distribution of macrofungi in várzea environments in the Brazilian Amazon is limited. This study aims to evaluate the diversity and composition of macrofungi on three várzea forest islands, while also examining differences in species richness and abundance between seasonal periods. A total of 88 macrofungal species that belong to the phylum Basidiomycota were identified. The findings revealed significant variations in species composition, yet no notable differences in species richness or abundance were observed between the seasonal periods. The environmental conditions and resources available to macrofungi appear to be consistent among the islands, which leads to a balanced diversity. However, additional research is essential to uncover the true distribution patterns of macrofungi in the várzeas of the Brazilian Amazon, an area under significant threat to its biodiversity. Full article

Determining the optimal harvest time for Pentaclethra macroloba seeds is essential to preserve germination potential and ensure high-quality oil production, valued in the pharmaceutical and cosmetic industries. This study aimed to identify the maturation phase that maximizes seed physiological quality and oil yield. Fruits and seeds were collected from 44 mother plants in Belém and São Domingos do Capim, Brazil, during three final maturation phases: P1 (dark green pericarp, beige seeds), P2 (yellowish-green pericarp, light-brown seeds), and P3 (black pericarp, dark brown seeds). Germination, vigor tests, and gas chromatography analyses revealed that seeds from P3 exhibited the highest vigor (93–99% germination) and oil yield (up to 13.1%). Major fatty acids were oleic (up to 65.23%), linoleic (up to 8.45%), and behenic acids (up to 17.22%). The ripening period ranged from 7 to 8 months, influenced by environmental factors. Optimal seed quality and oil yield are achieved when harvesting occurs before dispersal, targeting fruits with yellowish-green pericarp transitioning to black. Post-harvest drying enhances oil extraction efficiency. These findings support the conservation of P. macroloba through viable seeds and promote economic sustainability by optimizing oil production, benefiting biodiversity and local extractive communities. Full article