ABSTRACT Brazil stands out as one of the largest manufacturers of MDF (medium density fiberboard) in the world. The industries are concentrated in the south and southeast of the country and are primarily based on the use of Pinus and Eucalyptus wood, which are available in extensive planted areas. In the northern region, there is only one MDF industrial plant. Despite an abundance of potential raw materials in this region, there is a lack of studies on native species wood and their industrial waste utilization for MDF production. The present study aimed to evaluate the properties of MDF manufactured from a mixture of cultivated paricá (Schizolobium amazonicum) wood and wood waste from native Amazonian species. The study assessed the isolated effects of different proportions of the raw materials and panel thicknesses on MDF properties. Panels were produced, and samples were obtained for testing. Using standard procedures, the following properties were determined: density, water absorption, thickness swelling, internal bonding, static bending, and resistance to screw withdrawal. The results revealed a significant impact of the analyzed variables on some physical and mechanical properties of MDF. With the exception of internal bonding, all other properties of the evaluated MDF panels met the specified regulatory requirements for use in furniture manufacturing. It is concluded that mixtures of the assessed raw materials have great potential for MDF production in the furniture industry. However, adjustments in the production process are recommended to improve the internal bonding property.

ABSTRACT Deforestation, mining, pollution and the construction of hydroelectric plants are among the main risks for biological communities, ecosystems and indigenous peoples. In the Brazilian Amazon, historically there has been political pressure to reduce the constitutional rights of indigenous peoples, especially regarding mining activities and the construction of hydroelectric plants. This culminated in a law proposal allowing mining in indigenous lands (PL 191/2020), proposed during the last presidential term in Brazil (2018-2022), which sparked a heated debate in both the legal and ethical spheres. In this article we present objective arguments for the negative effects of mining on indigenous lands, using PL 191/2020 as a model to debate the consequences of such policies for biodiversity, ecosystem services, increased risks for humans due to pollutants and epidemics, and how this law violates the main objectives of the Agenda 2030 for sustainable development. Particularly in the Brazilian Amazon, the negative effects of this law on human life quality, economy and the ecosystems are greater than the supposed positive effects projected into the future. We suggest rethinking the feasibility of mining on indigenous lands and reiterate the importance of conserving these lands and other protected areas in the Amazon intact as a heritage of all Brazilians and the wider human kind.

ABSTRACT Bird droppings are an unusual food resource for coprophagous insects and used mostly by opportunistic decomposers. Among them, dung beetles feed mainly on dung, although the species differ in their trophic plasticity. Here we report a record of a dung beetle, Canthidium cf. gracilipes, reaching and manipulating the dropping of a passeriform bird, Dendrocincla fuliginosa (Dendrocolaptidae). The behavior was observed in an urban forest fragment located in the Amazonian city of Manaus, Brazil. Two hours after the bird defecated, the dung beetle reached the dropping and started manipulating them with its fore- and hindlegs. It did not eat the dung, though. For a clear understanding of the relationships between bird droppings and Amazonian dung beetles, it will be important to perform standardized experiments with a wide variety of native dung and carrion types.

ABSTRACT In the Amazon region, andiroba (Carapa guianensis) oil is among the most used products by the local population due to its medicinal properties. Previously, our group described the leishmanicidal activity of three limonoid-rich fractions from andiroba oil. This work aimed to evaluate the antioxidant activity and ultrastructural changes in Leishmania amazonensis treated with these limonoid-rich fractions from andiroba oil: 6α,11β-diacetoxygedunin; 11β-hydroxygedunin; and a fraction with both 6α,11β-diacetoxygedunin +11β-hydroxygedunin. The antioxidant activity was evaluated by the DPPH method and ultrastructural changes were evaluated by transmission electron microscopy. The fraction with both 6α,11β-diacetoxygedunin + 11β-hydroxygedunin displayed the best antioxidant activity (IC50 330.35 ± 8.60 µg mL-1; p=0.0022) compared to the 6α,11β-diacetoxygedunin fraction. The three fractions induced structural changes to mitochondria and kinetoplasts of L. amazonensis, in addition to lipid bodies, vacuolization, and vesicles in the flagellar pocket, indicating that the limonoid-rich fractions from andiroba oil can induce structural damage to Leishmania.

ABSTRACT Wild birds have great prominence in the transmission of diseases to humans, mainly due to their ease of access to human populations, raising concerns about the potential impact of that proximity on public health. The present study reports ARV and PBV occurrence in wild birds from an environmental protection area in the Amazon biome, in Pará state, Brazil. We obtained 155 fecal specimens from 47 species of wild birds for RNA extraction, ARV and PBV detection utilizing molecular methods, nucleotide sequencing, and phylogenetic analysis. ARV prevalence was 0.6% (1/155), being positive in an individual of Myrmotherula longipennis, and PBV prevalence was 1.29% (2/155), affecting two individuals of Guira guira. The PBV strains were assigned to genogroup I based on phylogenetic analysis, and they shared a strong phylogenetic link with strains isolated from different geographic locations. The ARV strain was more closely related to strains that had previously circulated in the same region. The presence of ARV and PBV in this habitat suggests that infection cycles of these agents occur naturally in the wild ecosystem, potentially triggering transmission events between bird species and humans. This is the first study on ARV detection in wild birds in Brazil and the first report on the occurrence of PBV in wild Guira guira. Additional studies are required to determine the epidemiology, origin, evolution, and emergence of new potentially pathogenic viruses in the Amazon.

ABSTRACT Drug repositioning seeks to discover new applications for a drug that has already been approved in the market, resulting in faster and lower cost solutions, generally used for diseases that receive little investment, such as cutaneous leishmaniasis. In this context, hesperidin, commercially approved as Daflon®, is a flavonoid that belongs to the chalcones group, a class that has antileishmanial potential. The present study evaluated the in vitro and in vivo antileishmanial activity of commercial hesperidin. Hesperidin (9 to 0.56 mg mL-1) was tested against promastigote and amastigote forms of four dermotropic species of Leishmania, namely L. (L.) amazonensis, L. (V.) guyanensis, L. (V.) braziliensis and L. (V.) naiffi. For the in vivo tests, hamsters were infected in the snout and the lesions were treated with intralesional hesperidin. The treatment effectiveness was assessed by measuring the total volume of the lesion on the snout and determining the parasitic load. The in vitro results showed moderate toxicity in murine macrophages, with higher efficacy in L. (L.) amazonensis when compared to the other species tested. The in vivo results showed that hesperidin was able to gradually reduce the size of lesions by L. (L.) amazonensis, although it did not induce clinical and parasitological cure. Thus, hesperidin showed potential in in vitro tests against L. (L.) amazonensis and further studies with new formulations and experimental treatment schemes should be carried out.

ABSTRACT Coating medicated fish feed with a polymer minimizes the chances of drug leaching into the water. Tambaqui (Colossoma macropomum) is an economically important Amazonian fish frequently parasitized by the acanthocephalan Neoechinorhynchus buttnerae. In this study, we compared the effect of ethylcellulose (EC 0.75%) coating of feed medicated with the antihelminthic albendazole (ABZ 10 mg kg bw-1) and uncoated feed on treatment efficacy and bioaccumulation of ABZ in naturally parasitized tambaqui during 35 days. Treatment efficacy was 34% and 66% in fish fed uncoated and coated feed, respectively, but did not vary significantly among treatments. Total ABZ residue reached concentrations from 122.0 to 151.7 ng g-1, and did not vary significantly among treatments. The biomagnification factor was low, ranging from 0.0003 to 0.0004. EC coating did not significantly affect the efficacy of ABZ treatment and did not interfere with ABZ bioaccumulation in the edible tissue of tambaqui.

ABSTRACT A new species of Philcoxia (Plantaginaceae) from Serra do Cachimbo, eastern Amazon, Brazil, is described and discussed. Philcoxia cachimboensis sp. nov. is mainly characterized by the corolla with asymmetrically obovate (liver-shaped) lateral lobes, with truncate to sub-emarginate apex. This is the first record of the genus in the Brazilian Amazon. A morphological description, illustration and photographs, conservation status assessment, an updated identification key for the recognized species of Philcoxia, and comparative taxonomic comments are provided.

ABSTRACT Apeiba (Malvaceae, Grewioideae) is an important component of the Neotropical flora, but taxonomic knowledge of its species is limited, particularly within the Amazon region. This study aimed to provide an updated taxonomic treatment of Apeiba native to Brazil, with focus on Amazonian collections. Species of Apeiba are trees with large yellowish-white flowers with a very particular fruit, an indehiscent capsule, usually globose to slightly flattened, covered either by long and numerous bristles, or densely apiculate. We provide synoptic descriptions for each Amazonian Apeiba species from Brazil, and comments on relevant synonyms and designated lectotypes for three names. We also provide an identification key, a list of examined material and distribution data, including a list of new occurrence records for some Brazilian states. Illustrations and notes on taxonomy and nomenclature are also included when appropriate.

ABSTRACT Croceous glands are visible structures defined by their rounded shape and yellowish color. They have great taxonomic importance, being used to delimit the Timutua section, one of the 14 sections of the subgenera Polygala, genera Polygala, the most representative of the family Polygalaceae, with about 120 species recorded in Brazil. However, detailed information about the nature of croceous glands is still missing. Thus, this study aimed to characterize the origin, structure, and function of the croceous glands in the floral structures, fruits, leaf blades, and stems of Polygala adenophora. Samples of P. adenophora at different developmental stages (flower buds, fully developed flowers and fruits), as well as stems, and leaves collected from the 1st, 3rd, 6th, and 9th nodes were obtained from a coastal area in Pará state, Brazil. The samples were fixed in FAA50 or buffered neutral formalin and submitted to light microscopy and scanning electron microscopy. Histochemical tests were carried out for lipophilic and hydrophilic compounds. Our results showed that the croceous glands are secretory cavities and ducts of schizolysigenous origin, present since the beginning of the development of vegetative and reproductive organs. The cavities and ducts produce a lipophilic compound consisting of essential oils and lipids. We hypothesize that this exudate possibly has a protective function, acting against pathogen and herbivore attacks.