Urban visceral leishmaniasis is intensifying across Amazonian cities, where ecological gradients, diagnostic divergence, and parasite adaptation complicate surveillance. We applied a One Health translational framework integrating diagnostic performance (TR DPP®, parasitology, kDNA, SSU rDNA), parasite microdiversity, ultrastructural remodel-ing, and extracellular vesicle (EV) biology across four municipalities. Among 1,499 dogs, infection burden was high and spatially heterogeneous. Agreement between TR DPP® and parasitology was substantial (κ = 0.6483), with 269 discordant outcomes reflecting distinct biological windows of infection. Blood and conjunctival swabs provided comple-mentary molecular detection, consistent with tissue specific parasitism. SSU rDNA se-quencing revealed low level polymorphisms compatible with intraregional microdiversity, while phylogenetic reconstruction confirmed genetic stability. Ultrastructural analyses identified lipid associated morphotypes and vesicle related structures supporting meta-bolic plasticity. EV release increased under thermal stress, indicating stress responsive ve-siculation with potential implications for immune modulation and diagnostic divergence. These integrated findings clarify how diagnostics, microdiversity, ultrastructure, and EV mediated communication converge to shape urban leishmaniasis dynamics and sup-port improved surveillance strategies for Amazonian endemic areas.

Global warming and industrial pollutants pose significant threats to environmental sustainability. In response, enzymes have emerged as promising tools for mitigating pollution. Enzymatic hydrolysis is considered environmentally sustainable due to its biological nature. In Brazil, the estimated agro-industrial waste production is an abundant source of lignocellulosic biomass, which contains cellulose, hemicellulose, and lignin. Its effective degradation requires a synergistic cocktail of enzymes, including cellulases, hemicellulases, and lignin-degrading enzymes. Within this system, β-glucosidases play a key role as a limiting factor in cellulose conversion, acting synergistically with other enzymes but being inhibited by glucose. This study aimed to produce and characterize β-glucosidases from the crude extract of the cyanobacterium Microcystis aeruginosa CACIAM 03. Enzyme production occurred after 10 days of incubation. The crude enzymatic extract exhibited optimal activity at pH 4.5 and 40°C (28.51 U/mL), high thermostability at 50°C (60% activity retained after 480 min), and tolerance to methanol (∼15% loss). The presence of Zn2+, Cl2+, and Mn2+ increased enzymatic activity by 2-3×. Using 300 µg of total protein from the crude enzymatic extract, the enzyme demonstrated high affinity for cellobiose, with K M app of 0.156 ± 0.02 mM and V ma x app of 0.246 ± 0.01 µM/min. These results reinforce the promising enzymatic potential of M. aeruginosa strains isolated from the Amazon region for sustainable biotechnological applications.

Lipid-rich and vesicle-like structures are recurrent features of Leishmania spp., yet their morphological diversity and stage-specific organization remain incompletely defined. Here, we provide a descriptive ultrastructural and fluorescence-based characterization of lipid-associated compartments in Leishmania (L.) amazonensis promastigotes and intracellular amastigotes using transmission electron microscopy, scanning electron microscopy, BODIPY® staining, and Nanoparticle Tracking Analysis (NTA). Promastigotes displayed electron-dense lipid bodies adjacent to the Golgi complex and abundant vesicle-like profiles within the flagellar pocket, whereas intracellular amastigotes exhibited rounded lipid-rich inclusions within parasitophorous vacuoles. NTA revealed stage-dependent differences in particle abundance and size distribution, interpreted strictly at the descriptive level in accordance with MISEV2023 guidelines. These findings establish a morphological baseline for lipid-associated structures across parasite stages. When contextualized with previously reported low-level genetic polymorphisms in Amazonian Leishmania populations, the observed structural heterogeneity suggests that microdiversity may contribute to variation in vacuolar lipid organization. This framework provides a foundation for future studies integrating ultrastructure, lipidomics, and parasite genomics.

The genus Kudoa is an important group of parasites within the class Myxozoa, as some species infect a wide range of fish hosts and cause post-mortem myoliquefaction, resulting in significant economic losses. This study describes a new species of Kudoa in toadfish Batrachoides surinamensis. In 60

Coccidia (Coccidiasina) is a subclass of Apicomplexa, known to cause gastrointestinal diseases in animals. Although its importance is recognized, there are few taxonomic studies of coccidia in fish, especially in biomes with high diversity, such as the Brazilian Amazon. Therefore, the present study investigated infections by coccidian microparasites found in the hepatic region of the Coco sea catfish, Bagre bagre. Parasitological analyses were performed on 50 specimens of B. bagre collected in Bragança and Curuça, in northern Brazil, between January and December 2021. Infections caused by coccidiosis were identified in 35 of these specimens, which were infected by parasites of the genus Calyptospora, including both sporulated and non-sporulated forms in the hepatic stroma of the hosts. The oocysts were spherical (mean diameter: 10.52 ± 0.29 μm) and contained four spheroid sporocysts (mean diameter: 4.22 ± 0.23 μm). A consensus sequence (1,320 bp) of the SSU rDNA gene from these parasites was compared with GenBank sequences of other species of the class Coccidiomorphea and the genetic distances indicated that they represented a new species. The combination of the morphometric and phylogenetic evidence supports conclusively the existence of a new species of the genus Calyptospora, which is denominated Calyptospora matosi n. sp.

Canine monocytic ehrlichiosis, canine thrombocytic anaplasmosis, and canine babesiosis are diseases caused, respectively, by bioagents Ehrlichia canis, Anaplasma platys e Babesia vogeli, that have gained great relevance due to its zoonotic character. The hot and humid climate in the Amazon region favors the proliferation of hematophagous vectors. The present study investigated the prevalence of E. canis , A. platys, and B. vogeli during the years 2013 to 2017 through the analysis of the database with results of tests carried out on blood samples of 6,593 responsible guard dogs in the Metropolitan Region of Belém-PA, using the Polymerase Chain Reaction method (PCR), developed by the Laboratory of Biomolecular Technology, of the Federal University of Pará. The frequency of infections in all years of study was 29.13% for E. canis, 15.30% for A. platys, and 9% for B. vogeli. In addition, there was an increase in infection by E. canis and A. platys over the years and a reduction in infection by B. vogeli. In the analysis of co-infections, the number of animals infected simultaneously by E. canis, and A. platys indicates an association between these bacteria, different from infection by B. vogeli. The present research developed in the Metropolitan Region of Belém indicates that studies of the population dynamics of the vector tick must be carried out in the city so that control measures can be established to combat hemoparasitosis caused mainly by E. canis and A. platys, which has increased significantly each year and due to its zoonotic character.

This study reports the occurrence of a myxosporid parasite of the genus Ceratomyxa Thélohan, 1892 found in the gallbladder of Curimata cyprinoides Linnaeus, 1766. This species is abundant in the Tocantins-Araguaia hydrographic basin and holds environmental, social and economic importance. The genus Ceratomyxa is characterized by two equally-sized polar capsules with lateral projections, whick may appear slightly slightly arched in a half-moon shape or fully curved arched. Light microscopy and molecular analysis were employed in this study. The mature spores were composed of two equally-sized symmetrical valves with equal capsular foramina and two equally-sized lateral projections. These spores (n=40) were freely suspended in the gallbladder, with a total length of 11.2 ± 0.1 μm and width of 4.0 ± 0.3 μm. The polar capsules measured 2.1 ± 0.1 μm in both length and width; and the two symmetrical lateral elongations formed a posterior angle of 41.4º ± 0.7º. An integrated comparative analysis of the morphological characteristics and partial SSU rDNA sequences confirmed this finding as a parasite of the genus Ceratomyxa sp., located in the gallbladder of C. cyprinoides in the Tocantins-Araguaia basin, within the municipality of Araguatins, in eastern Amazon, Brazil.

The Brazilian Amazon estuary is a highly dynamic environment, characterized by substantial organic matter input and a rich diversity of fish species that utilize this ecosystem for feeding and reproduction. Despite its ecological relevance, ichthyo-parasitological research in the region remains limited, particularly regarding the diversity of parasitic species within the class Myxozoa. Among the fish species for which parasitological data are still scarce is the Pacamã frogfish, Batrachoides surinamensis (Bloch and Schneider, 1801), a demersal species that feeds on small invertebrates and fish. The present study describes the morphological, molecular and phylogenetics aspects of Ortholinea abadiensis n. sp., a new species isolated from the urinary bladder of the B. surinamensis, collected on the coast of the Brazilian Amazon. Myxospores were observed dispersed in the liquid of the urinary bladder in 16 of the 20 specimens (80 %) of the specimens analyzed. The myxospores were subspherical with 18 to 20 superficial ridges and measured, 6.7±0.2 (6.3-7.1) µm in length, 6.0±0.5 (5.6-6.5) µm in width, and 6.1±0.1 (5.9-6.2) µm in thickness. The polar capsules were symmetrical and semispherical, with openings in opposite directions to the valves, which were 2.6±0.2 (2.2-3.2) µm in length and 2.4±0.1 (2-2.6) µm in width, with 5 to 6 turns of polar tubules. Morphometrically and morphologically, this species was distinct from other previously described Ortholinea. In the SSU rDNA phylogeny, O. abadiensis was positioned within a clade comprising marine species, with O. nupchi identified as its sister species. This study provides new morphological and molecular insights into a new species of the genus Ortholinea in a fish with a wide geographic distribution in South America.

Leishmania parasites often infect different host types over the course of their complex life cycle, and the interspecific correlations exist between traits expressed in natural reservoirs and potential new hosts or vectors. Comparable to other eukaryotes, Leishmania release extracellular vesicles that promote crucial interactions, modulating the subsequent systemic immune response to establish host infection, which seriously affects the health of humans and pets (dogs or cats). Recent studies in endemic areas of Brazil concluded that canine leishmaniases were predominantly due to Leishmania amazonensis and not restricted to Leishmania infantum (syn. Leishmania chagasi). Under these premises, the diagnosis of canine leishmaniasis needs improvement, including the identification of the current etiological agent, clinical differential diagnosis, and histopathologic features. The study aims to achieve two main objectives: to present findings on natural canine infections and to highlight the importance of differential diagnosis in companion animals. It also seeks to investigate the role of lipids in Leishmania extracellular vesicles (LEVs) in vitro, focusing on the emerging research area that explores the mechanisms and biological aspects of parasite–host interactions. In essence, the study aims to bridge gaps in our understanding of how lipids in LEVs influence parasite–host interactions, while emphasizing the significance of accurate diagnosis in companion animals. Therefore, future studies of parasitology research for both fields are important for advancing diagnostics, prognostics, and treatments, as well as addressing the ongoing global need for prevention, control, elimination, and eradication.

Calyptosporidae are heteroxenous coccidia with fish as their definitive hosts. Currently, most of this diversity is found in freshwater fish from the Brazilian Amazon region. The objective of this study was to perform an integrative taxonomy of a new species of Calyptospora in Cynoscion virescens (Cuvier, 1830), a marine and estuarine fish. Thirty specimens of C. virescens from the Eastern Amazon were collected and necropsied, of which 12 (40 %) were infected after microscopic analysis, which has revealed spherical oocysts measuring 17.8 μm in diameter and four elliptical sporocysts with 7.1 μm in length and 6.1 μm in width. The oocysts were located in the hepatopancreas, and melanomacrophagic bodies were observed in nearby regions. In phylogenetic analysis, coccidia were found in the basal clade of the Calyptosporidae family. Morphological and molecular divergence characterized a new species of Calyptospora in C. virescens, the first occurrence of coccidia in a fish of the family Sciaenidae.

The main objective of the study is to perform a descriptive analysis of cases of Cutaneous and Visceral Leishmaniasis in humans in the Metropolitan Health Region I, which is made up of Belém, Ananindeua, Benevides and Marituba, in the State of Pará, in the period from 2012 to 2022. Data on reported cases were collected from the database of the State Health Department. In the studied period, 235 cases were analysed, 179 of TL and 56 of VL. In Belém, 46.7% of cases occurred in individuals under 19 years of age, indicating a significant impact on the younger population, while Ananindeua had 68.5% with 30 years or older, suggesting a higher risk for older individuals there, as well as in the neighbouring cities of Marituba and Benevides. Belém had more cases in the low education category and Ananindeua had more cases with intermediate education. Regarding the medications used in treatment, Pentavalent Antimonial was the most common, accounting for 77.1% of the total use of medications of choice. Regarding the origin of the cases, the "Autochthonous" category was more prevalent in Ananindeua. Most cases were laboratory confirmed. Of the cases in Ananindeua, 44.9% were work-related, and Belém had the highest proportion of cured patients (66.2%). The differences in incidence rates between municipalities indicate local influences, such as deforestation and socioeconomic characteristics. Autochthonous cases alert to the presence of local vectors, highlighting the need for increased surveillance measures. The presence of records with missing data reinforces the need for improved data collection, which is crucial for analyses that generate indicators that lead to the development of public policies to combat leishmaniasis.

Metallothioneins (MTLs) are small, cysteine-rich proteins known for their ability to bind metal ions and exhibit flexible, disordered structures. The structural and functional characteristics of metallothionein I (MTL-1) from Caenorhabditis elegans were investigated, focusing on its behavior in both metal free (MTL-1 Apo) and metal-bond states with Zn2+, Cd2+, Cu2+, Hg2+, and Pb2+ divalent metal ions. Using molecular dynamics simulations and 3D modeling via AlphaFold, we characterized the flexibility and stability of MTL. The MTL-1 Apo form displayed high flexibility, aligning with its intrinsically disordered protein (IDP) nature, with 89.3% of its structure composed of coils, bends, and turns. Metal binding significantly enhanced the protein's stability, particularly with Zn2+, Cd2+, Cu2+, and Hg2+, reducing root mean square deviation (RMSD), root mean square fluctuation (RMSF), accessible surface area (SASA) and radius of gyration (R g) values, indicating structural compaction. Conversely, Pb2+ showed a weaker stabilizing effect, with a more dynamic and less stable structure. Structural analysis revealed that conserved cysteine residues coordinate the metal through strong thiolate interactions, with additional contributions from non-cysteine residues, such as Glu and Lys. The study underscores the importance of incorporating intrinsically disordered protein models in MD simulations to provide deeper insights into how metallothionein's flexibility and stability vary in response to different metal ions, offering a structural perspective on their biological interactions and behavior under diverse environmental conditions. While thermodynamic aspects were not directly assessed, the results reveal consistent conformation trends across different metal coordination states.

Cyanobacteria, photoautotrophic microorganisms found in diverse environments, are promising producers of bioactive compounds with industrial applications. Among these, α-Amylases hydrolyze α(1,4) glycosidic bonds in starch, generating fermentable monomers for bioprocesses. This study used computational approaches to identify and characterize potentially thermostable α-Amylases from cyanobacterial sequences from a public database. The protein Amy1 was identified and analyzed through structural modeling, sequence comparison, molecular dynamics simulations, and binding free energy calculations to assess protein-ligand interactions. Molecular dynamics at 27 °C and 50 °C were conducted to evaluate putative enzyme stability, guiding experimental validation of thermostability. These studies were carried out to ensure accuracy for experimental tests, which are important to confirm this thermostable characteristic. These findings highlight cyanobacterial alpha-amylase characteristics as viable alternatives to commercial equivalents and pave the way for future biotechnological applications and large-scale production.

Leishmaniases are zoonotic vector-borne diseases caused by a wide variety of Leishmania species with complex transmission cycles involving different reservoirs, potential new hosts and vectors. Similarly, to other eukaryotes, Leishmania release extracellular vesicles (LEVs) to play important initial interactions that are crucial to modulate the subsequent systemic immune response on the establishment of infection in humans and others hosts like dogs. Recent studies in endemic areas of Brazil concluded that canine infections were predominantly due to L. amazonensis and not restricted to L. infantum (syn. Leishmania chagasi). Under these premises, the diagnosis of leishmaniasis needs to be improved with the identification of current etiological agent and the histopathologic features, highlighting the differential diagnosis and the molecular components of LEVs. In this way, the dual aim of that study is to register collected observations of natural canine infections, enhancing the relevance of differential diagnosis in companion animals and inserting in vitro results in the field of LEVs that still research gaps to be filled to understand the mechanisms and biological aspects involving the parasite-host interactions. Therefore, improve these studies of Parasitology research is important for diagnostic, prognostic, treatment advances and continuing need for global prevention, control, elimination/eradication of these parasitic infections.

Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of β(1-4) glycosidic bonds and have attracted considerable attention because of their potential for enhancing efficiency in degrading recalcitrant polymeric substrates, in synergism with hydrolytic enzymes. Fungal-derived LPMOs are the most prevalent type, while other taxonomic groups have been described as potential alternative sources of these enzymes. In the present study, we aimed to identify and characterize in silico a LPMO of cyanobacterial origin with putative functions in chitin depolymerization. A similarity search of sequences and conservation of domains with characterized LPMOs identified a 289 amino acid protein from the cyanobacterium Mastigocoleus testarum (Order Nostocales), likely belonging to the CAZy-AA10 class. This protein is referred to as MtLPMO10. Phylogenetic analysis revealed that MtLPMO10 is homologous to the protein Tma12 from the fern Tectaria macrodonta, with 52.11 % sequence identity, which was the first LPMO characterized as originating from the plant kingdom. The protein tertiary structure predicted by the AlphaFold server indicates structural features common to LPMOs, such as a histidine brace formed by His31 and His132 and an immunoglobulin-like domain composed of antiparallel beta strands. Molecular dynamics (MD) simulation allowed the assessment of the enzyme-substrate affinity, using an initial pose based on literature data. The MtLPMO10-chitin complex remained stable during 100ns of MD, while the MtLPMO10-cellulose complex dissociated within 30ns of MD. Additionally, there was a shorter Cu(I)-H4 distance in the protein-substrate complex compared to the Cu(I)-H1 distance (averages of 6.0 ± 0.7 Å and 7.9 ± 0.7 Å, respectively), suggesting a C4 regioselectivity. This study highlights the existence of lytic polysaccharide monooxygenases in cyanobacteria and paves the way for further investigations related to this enigmatic class of enzymes and their potential use in biotechnological applications.

The mapará (Hypophthalmus marginatus) is a commercially important fish in the Brazilian Amazon and has been described as a host for numerous myxosporid species. The integrated taxonomy of a new species, Myxobolus mickeyii n. sp., discovered in the urinary bladder of H. marginatus, is undertaken in this study. In 105 specimens of H. marginatus, plasmodia and myxospores were observed in the urinary bladder fluid, the myxospores measuring 20.5 (19.6-21.3) μm in length and 14.0 (13.2-14.9) μm in width. The posterior valves of the spore body were thick, with valvulogenic nuclei, endoplasmic reticulum, and the presence of secretory vesicles. Two elliptical, rounded appendages attached to the valve, containing tubular filaments. The two polar capsules, symmetry, measuring 6.1 (5.9-6.3) μm in length and 4.4 (3.6-6.2) μm in width, with polar tubules of 3 to 5 turns. Phylogenetic analyses of the small subunit ribosomal RNA gene (SSU rDNA) sequencing revealed that M. mickeyii n. sp. is part of a Myxobolidae family clade with freshwater fish of the Siluriformes order, with a genetic distance of 19% to the nearest species. This work contributes to the wide diversity of myxozoans in this host, as other taxa have previously been reported infecting different tissues.

Renewable energy has been recognized as an alternative to fossil fuels as a step to transform the energy produced and consumed worldwide. Cyanobacteria and microalgae are currently being considered as substitutes to the traditional feedstock used to produce biofuels due to their ability to achieve high amounts of lipids under cellular stress conditions. The aim of this study was to investigate the utilization of Tolypothrix sp. CACIAM 22 cyanobacterial biomass as a feedstock for biodiesel production, specifically by examining the effects of supplementing with hydrolysate of Brazil nutshell (HBNS) on biomass generation, lipid production, fatty acid composition, and quality of synthesized biodiesel. The supplementation of HBNS led to a significant increase of 12g. L- 1 in wet biomass production. The lipid content reached 41 % of the biomass produced in HBNS supplemented cultures when nitrate source was deprived. The quality evaluation of cyanobacteria-derived biodiesel was performed using Biodiesel Analyzer ver 2.2 software, revealing superior quality compared to biodiesel produced from plant sources. The biodiesel exhibited values of 23 h for oxidative stability, 65 for cetane number, and an iodine index of 31 (g I2. 100 g- 1 fat), indicating promising potential as a renewable source. This study is the first to utilize HBNS as an organic supplement for cyanobacteria culture medium and assess its impact on biomass and lipid production in Tolypothrix sp., supporting the hypothesis of utilizing this biomass as a renewable feedstock for biodiesel production as a viable alternative to plant sources based on biomass production, lipid productivity, and biodiesel quality.

Cyanobacteria, a group of photosynthetic prokaryotes, can sinthesize several substances due to their secondary metabolism, with notable properties, such as Cyanovirin-N(CVN), a carbohydrate-binding lectin, that exhibits antiviral activity against several pathogens, due to its ability to bind viral surface carbohydrates such as mannose, thus interfering with the viral entry on the cell. CVN has been described in several cyanobacterial strains and shows biotechnological potential for the development of drugs of pharmaceutical interest. This study focuses on the genomic exploration and characterization of Cyanovirin-N homologs to assess the conservation of carbohydrate-binding affinity within the group. The analysis of their antiviral properties was carried out using bioinformatics tools to study protein models through an in silico pipeline, following the steps of genomic prospection on public databases, homology modeling, docking, molecular dynamics and energetic analysis. Mannose served as the reference ligand, and the lectins' binding affinity with mannose was assessed across Cyanovirin-N homologs. Genomic mining identified 33 cyanobacterial lectin sequences, which underwent structural and functional characterization. The results obtained from this work indicate strong carbohydrate affinity on several homologs, pointing to the conservation of antiviral properties alongside the group. However, this affinity was not uniformly distributed among sequences, exhibiting significant heterogeneity in binding site residues, suggesting potential multi-ligand binding capabilities on the Cyanovirin-N homologs group. Studies focused on the properties involved in these molecules and the investigation of the genetic diversity of Cyanovirin-N homologs could provide valuable insights into the discovery of new drug candidates, harvesting the potential of bioinformatics for large-scale functional and structural analysis.