Search Results (612)

Fusarium head blight (FHB) is a major threat to wheat production that is caused by toxigenic species of the Fusarium graminearum complex. This study aimed to investigate the biochemical and molecular defense responses of Brazilian wheat genotypes (BRS 194, BRS Parrudo, and Frontana) with contrasting FHB susceptibilities following inoculation with F. graminearum (deoxynivalenol producer) and F. meridionale (nivalenol producer). Temporal patterns of antioxidant enzymes, defense-related enzymes, and gene expression (ABC-Transporter and Ca²⁺-ATPase) were analyzed from 12 to 96 h after inoculation. The ANOVA results revealed significant effects of genotypes, inoculation, and time after inoculation on most of the evaluated enzymatic activities. Frontana exhibited high basal activity for most enzymes, and after inoculation, the enzyme activity was higher than in other genotypes. BRS 194 presented delayed and fragmented activation patterns, particularly under DON-producing pathogen infection. According to the transcriptome results, inoculation with the NIV-producing pathogen upregulated both genes, reaching up to an 18-fold increase. BRS 194 showed an upregulated transcript pattern from the early hours after inoculation. Frontana showed increased transcript levels, reaching 12-fold, under DON-producing pathogen infection. These findings show that biochemical and molecular responses varied depending on genotype and the chemotype of the Fusarium isolate, highlighting the importance of early, coordinated defense activation in FHB resistance. Full article

Plant density influences interspecific interactions such as pollination and herbivory. In denser populations, pollinators find flowers more easily, increasing reproductive success and population growth. However, the same floral attractiveness also favors floral herbivory, a relationship described by Janzen and Connell as negative density dependence, considered an important mechanism for maintaining tropical diversity. This study analyzed the reproduction of Peixotoa tomentosa A. Juss. (Malpighiaceae) and Byrsonima intermedia A. Juss. (Malpighiaceae), considering population density and its influence on pollinator and herbivore attraction. The central hypothesis was that density affects fruit production. We conducted two treatments with both species: high density and low density in a preserved Brazilian savanna. We investigated fruit production, reproductive system, floral visitation rates, and the florivory rates of each species on each treatment. Our results showed that fruiting increased with density in both species. Peixotoa tomentosa is an agamospermous species, while B. intermedia is self-incompatible and relies exclusively on pollinators. Bees visited only B. intermedia, and the high-density treatment received more visits. Herbivores attacked more isolated P. tomentosa flowers. We concluded that density influences both pollination and herbivory, affecting plant reproduction, with effects mediated by the plant’s attractiveness in denser populations and by the size and quantity of flowers in single individuals. Full article

This study investigated the diversity and distribution of phytopathogenic fungi associated with goosegrass (Eleusine indica), an aggressive weed in agriculture, and bioprospected fungi isolates with potential for biological control of this species. Samples showing disease symptoms were collected from Goias, Minas Gerais, and São Paulo (Brazilian states), resulting in 88 isolates, of which 50 were phytopathogenic to E. indica. A total of 26 isolates were considered more aggressive based on visual analysis and were preliminarily identified at the genus level, with an emphasis on Bipolaris, Fusarium, Curvularia, Exserohilum, and Alternaria. The influence of climatic factors, such as sunny days (UV radiation), temperature, and precipitation on fungal occurrence was analyzed. These climatic factors are critical to the presence of fungi, providing insights into their potential as biological control agents and guiding future surveys of specific genera. The number of sunny days during surveys influenced the occurrence of fungi associated with E. indica, depending on the genera of the fungi. In addition, precipitation was also a determining factor for a higher incidence of fungal isolates during periods of increased rainfall, suggesting a positive relationship between relative humidity and the dispersal or infection of phytopathogenic fungi. New tests will be conducted to confirm the potential of the identified plant phytopathogenic fungi as biological control agents against E. indica. Full article

The highly pathogenic avian influenza H5N1 2.3.4.4b clade virus has caused widespread outbreaks across South America, primarily affecting seabirds, poultry, and marine mammals. The virus likely reached the continent through migratory birds from North America, initially spreading along the Pacific coast before advancing into Atlantic-bordering countries such as Argentina, Uruguay, and Brazil. This study investigated the dynamics of H5N1 strains in Uruguay during outbreaks from February and October 2023. We analyzed an updated South American database, including a newly sequenced viral genome from a royal tern (Thalasseus maximus) collected at the end of the outbreaks. Phylogeographic reconstruction revealed two distinct South American phylogroups comprising Uruguayan strains: one mainly driven by wild birds and poultry, with the royal tern strain clustering with Brazilian isolates, and another primarily associated with marine mammals, displaying adaptive residues in the PB2 protein. In Uruguay, these phylogroups delineate two main transmission routes: (i) an avian-derived pathway originating in Argentina and (ii) a pinniped-derived route from Chile. Brazil, initially colonized via the Argentine route, later emerged as a secondary source for Uruguay. This host-pathway interplay underscores the virus’s cross-species potential and highlights the need for coordinated regional surveillance within a One Health framework to mitigate zoonotic risks. Full article

Swietenia macrophylla King, commonly known as Brazilian mahogany, is a high-value neotropical tree species currently threatened due to intensive logging in previous decades. Technologies aimed at clonal production are essential for this species’ conservation and sustainable use at times of climate change and increasing demand for ecological restoration. The aim of the present study is to develop a low-cost protocol for mahogany clonal propagation through mini-cutting by assessing clonal mini-hedge nutrition, vegetative propagule type and indole-3-butyric acid (IBA) application effects on rooting and early clone growth. The experiment was conducted in nursery under controlled conditions based on using basal and apical mini-cuttings rooted in a low-cost mini-greenhouse subjected to three nutrient solution concentrations (50%, 100%, and 200%) and five IBA doses (0–8000 ppm). The mini-cutting technique proved efficient and led to over 90% survival after the hardening phase. The 200% nutrient solution concentration allowed balanced performance between cutting types and optimized clonal yield. IBA concentration at 4000 ppm accounted for higher root percentages at the bottom of the tube and the trend towards higher dry biomass production at 160 days. The results highlighted mini-cutting’s potential as a viable mahogany conservation and sustainable production technique. It also supported tropical forestry sector adaptation to challenges posed by climate change. Full article

Sporotrichosis is a zoonotic fungal infection with increasing incidence in the Brazilian Amazon, primarily affecting domestic cats and posing risks to human health. This study characterized the clinical and epidemiological profiles of 29 feline sporotrichosis cases in Manaus and optimized molecular diagnostic methods for Sporothrix species identification. Most affected cats were young (86.2% aged 1–3 years), male (82.7%), and free-roaming or semi-indoor (44.8% each), frequently presenting cutaneous lesions localized at the nasal planum (23.3%), ears (7%), eyes (2.3%) and other facial areas (18.6%). Three DNA extraction methods were compared; the phenol–chloroform protocol yielded the highest DNA concentration and purity, and ITS1–ITS4 primers showed an adequate sensibility for PCR detection. In silico RFLP profiles using common restriction enzymes showed limited discriminatory power among Sporothrix species. ITS sequencing of four high-quality amplicons confirmed all isolates as Sporothrix brasiliensis. Antifungal susceptibility testing of all isolates revealed geometric mean MICs of 0.25 µg/mL for ketoconazole, 0.57 µg/mL for itraconazole, 7.27 µg/mL for amphotericin B, and 64 µg/mL for fluconazole, respectively. These findings provide clinical, molecular, and therapeutic information supporting the diagnosis and surveillance of feline sporotrichosis in the Amazon, reinforcing the need for ongoing veterinary and public health monitoring. Full article

Metagenomic studies have provided deeper insights into the complex interactions between the skin and its microbiota. However, limited research has been conducted on the skin microbiota of Brazilian women. Given that Brazil ranks as the fourth-largest consumer of cosmetics worldwide, the development of new tools to analyze skin microbiota is crucial for formulating cosmetic products that promote a healthy microbiome. Skin samples were analyzed using the Illumina platform. Biometrology assessments were applied. The results showed pH variations were more pronounced in the older age group, along with higher transepidermal water loss values. Metagenomic analysis showed a predominance of Actinobacteria (83%), followed by Proteobacteria (7%), Firmicutes (9%) and Bacteroidetes (1%). In the older group (36–45 years old), an increase in Actinobacteria (87%) was observed and a decrease in Proteobacteria (6%). Moreover, the results differ from the international literature, since an increase in proteobacteria (13.9%) and a decrease in actinobacteria (46.7%) were observe in aged skin. The most abundant genus identified was Propionibacterium (84%), being the dominant species. Interestingly, previous studies have suggested a decline in Cutibacterium abundance with aging; although there is no significant difference, it is possible to observe an increasing trend in this genus in older skin. These studies can clarify many points about the skin microbiota of Brazilian women, and these findings could lead to the development of new cosmetics based on knowledge of the skin microbiome. Full article

Background/Objectives: Actinobacteria are one of the largest bacterial phyla. These microbes produce bioactive compounds, such as antifungals, antibiotics, immunological modulators, and anti-tumor agents. Studies on actinobacteria isolated from the Brazilian Savannah biome (Cerrado) are scarce and mostly address metagenomics or the search for hydrolytic enzyme-producing microbes. Solanum lycocarpum (lobeira) is a tree widely employed in regional gastronomy and pharmacopeia in Central Brazil. Methods: In this work, 60 actinobacteria isolates were purified from the rhizosphere of S. lycocarpum. Eight Streptomyces spp. isolates were selected for in vitro antifungal activity against Cryptococcus neoformans H99, the C. neoformans 89-610 fluconazole-tolerant strain, C. gattii NIH198, Candida albicans, C. glabrata, and C. parapsilosis. The ability of the aqueous extracts of the isolates to induce the in vitro secretion of tumor necrosis factor (TNF-α), nitric oxide (NO), interleukin-6 (IL-6), and IL-10 by murine macrophages was also evaluated. Results: All extracts showed antifungal activity against at least two yeast species. Streptomyces spp. LAP11, LDB2, and LDB17 inhibited C. neoformans growth by 40–93%. Most extracts (except LAP2) also inhibited C. gattii. None inhibited C. albicans, but all inhibited C. glabrata (40–90%). Streptomyces sp. LAP8 extract increased nitric oxide production by approximately 347-fold in murine macrophages, while LDB11 extract suppressed LPS-induced TNF-α production by 70% and simultaneously increased IL-10 secretion, suggesting immunosuppressive potential. Conclusions: The results revealed that Cerrado actinobacteria-derived aqueous extracts are potential sources of antifungal and immunomodulatory biocompounds. 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

Simian foamy virus (SFV) is a retrovirus that infects primates. However, epidemiological studies of SFV are often limited to captive populations. The southeastern Brazilian Atlantic Forest is home to both an endemic, endangered species, Leontopithecus rosalia, and an introduced species, Leontopithecus chrysomelas, to which no data on SFV exist. In this study, we assessed the molecular prevalence of SFV, their viral load, and their phylogenetic relationship in these two species of primates. Genomic DNA was extracted from 48 oral swab samples of L. chrysomelas and 102 of L. rosalia. Quantitative PCR (qPCR) was performed to diagnose SFV infection and quantify viral load. SFV prevalence was found to be 23% in L. chrysomelas and 33% in L. rosalia. No age-related differences in prevalence were observed; however, L. rosalia showed a higher mean viral load (3.27 log10/10⁶ cells) compared to L. chrysomelas (3.03 log10/10⁶ cells). The polymerase gene sequence (213 pb) of L. rosalia (SFVlro) was clustered within a distinct SFV lineage found in L. chrysomelas. The estimated origin of SFVlro dated back approximately 0.0836 million years ago. Our study provides the first molecular prevalence data for SFV in free-living Leontopithecus populations while offering insights into the complex evolutionary history of SFV in American primates. Full article

Background: Arthropod-borne diseases primarily affect tropical and subtropical regions, exhibiting seasonal patterns that peak during hot and rainy months when conditions favor mosquito vector proliferation. Factors such as high temperatures, elevated humidity, rainfall, urbanization, and the abundance of natural and artificial breeding sites influence Aedes vector dynamics. In this context, arboviruses pose significant public health challenges, likely worsened by global warming. In Brazil, Aedes (Stegomyia) aegypti (Linnaeus, 1762) is the primary vector for yellow fever, dengue, chikungunya, and Zika. Aedes (Stegomyia) albopictus (Skuse, 1894) is an important global arbovirus vector and is considered a potential vector in Brazil. Entomological surveillance of these species often uses oviposition traps targeting immature stages. Evaluating studies that use ovitraps to collect Ae. aegypti and Ae. albopictus egg is essential for improving mosquito surveillance strategies. This study systematically reviewed peer-reviewed articles on ovitrap-based surveillance of Aedes mosquitoes in Brazil, published in Portuguese and English from 2012 to 2022. The findings suggest that ovitraps are an effective method for detecting the presence or absence of Ae. aegypti and Ae. albopictus, serving as a reliable proxy for estimating mosquito abundance in Brazilian contexts. Full article

Fusarium head blight in barley (Hordeum vulgare) reduces grain yield and can lead to the accumulation of deoxynivalenol (DON) and nivalenol (NIV) in grains. We surveyed Fusarium species and evaluated DON and NIV concentrations in barley grains in four regions of Rio Grande do Sul, the southernmost state in subtropical Brazil. Seven Fusarium species were identified: F. asiaticum, F. avenaceum, F. cortaderiae, F. graminearum, F. gerlachii, F. meridionale and F. poae. DON (0 to 10,200 µg/kg) and NIV (0 to 1630 µg/kg) were detected in 74% and 70% of the samples, respectively, with higher concentrations found in experimental fields. However, in commercial barley fields, most samples fell below 2000 µg/kg of DON, which is the maximum limit allowed by Brazilian legislation for grains intended for processing. The seasonality of temperature and precipitation influenced mycotoxin concentrations. Therefore, the variability of Fusarium species in Rio Grande do Sul and a high incidence of DON and NIV in barley grains highlight the complexity of this pathosystem. This variability of Fusarium species may also influence the effectiveness of measures to control the disease, particularly in relation to genetic resistance and fungicide application. Full article

In contrast to mercury, an extremely toxic element, selenium is an essential micronutrient, which by complexing with mercury can mitigate its toxicity. In this regard, we quantified mercury and selenium concentrations in samples (n = 309) of fish tissues and analyzed the Se:Hg molar ratio and HBVSe as toxicological risk biomarkers. The data indicated that mercury levels in planktivorous fish (0.630 ± 0.202 mg kg⁻¹) and carnivorous fish (1.196 ± 0.513 mg kg⁻¹) were above the Brazilian limits considered safe for daily consumption. The highest selenium concentrations were observed in planktivores (0.272 ± 0.093 mg kg⁻¹) and the lowest in herbivores (0.099 ± 0.092 mg kg⁻¹). Molar ratios greater than one and positive HBVSe values were found in 42% of the fish samples (n = 131). As a result, we found that (i) the trophic level influences the risk of mercury exposure through the intake of fish in the diet; (ii) the approach presented in our study (model II) involves greater rigor concerning intake and exposure via fish consumption, since it considers the antagonistic Se:Hg ratio; and (iii) selenium can attenuate mercury toxicity, but safe thresholds vary depending on the species. Full article

The Brazilian Araucaria Forest (AF) now covers only 1% of its original extent due to significant degradation, making conservation a challenge. The AF occurs in a mosaic alongside grassland and Atlantic Forest ecosystems, influencing bird species’ distribution through ecological processes. We compared the composition and functional diversity of the bird community along a gradient of AF cover in a protected area (Pró-Mata Private Natural Heritage Reserve) in southern Brazil. Bird sampling was conducted using MacKinnon lists along five trails with different histories of vegetation suppression, based on forest cover estimates from landscape imagery. Birds were functionally classified based on morphological and ecological traits. We recorded 191 bird species in total. We found higher bird richness in trails with less forest cover, while functional diversity responded inversely to vegetation cover. Bird species composition shifted from more open-habitat specialists to more forest specialists with the increasing forest cover and vegetation structural complexity. These findings highlight the ecological importance of maintaining vegetation heterogeneity, as vegetation mosaics enhance avian species richness and support a broader range of functional traits and ecosystem processes. We recommend the conservation of Araucaria Forest–grassland mosaics as a strategic approach to support multidimensional biodiversity and sustain key ecological functions in southern Brazil. Full article

Beans (Phaseolus vulgaris and P. lunatus) are the major hosts of bean golden mosaic begomovirus (BGMV). Robust taxonomic criteria were established for Begomovirus species demarcation. However, DNA–A identities among BGMV isolates display a continuous variation (89–100%), which conflicts with the current concept of a single viral species. The diversity of 146 Brazilian isolates designated in the GenBank as BGMV was assessed by comparing their complete DNA–A sequences. The isolates were clustered into four groups, being discriminated mainly by their original Fabaceae hosts. Additional Sequence Demarcation Tool analyses indicated that BGMV-related viruses comprise two clear-cut groups: isolates reported infecting mainly P. vulgaris (identities of 96–97% to the reference NC_004042 isolate) and a group associated with P. lunatus (identities of 89–91%). Moreover, we recognized a distinct set of genomic features in the iterons and Rep-associated protein motifs across these two diversity groups. The host prevalence and genomic differences suggest that most P. lunatus isolates are currently misclassified as BGMV strains, being more likely samples of a closely related (but distinct) Begomovirus species. Hence, the implications of this BGMV diversity should be taken into consideration by classical and biotech breeding programs aiming for large-spectrum viral resistance in Phaseolus species. Full article