Aqueous extract of the bark of Uncaria tomentosa, an amazonian medicinal plant, promotes gastroprotection and accelerates gastric healing in rats.

ETHNOPHARMACOLOGICAL IMPORTANCE: Uncaria tomentosa Willd. DC., is used in the Amazonian region of South America, wherein ethnic groups use the plant to treat diseases, including gastric disorders. However, despite its widespread popular use, this species has yet to be assessed for its anti-ulcer effects. AIM OF THE STUDY: In this study, we aimed to evaluate the in vivo gastroprotective and gastric healing activities of an aqueous extract of the bark of Uncaria tomentosa (AEUt) and sought to gain an understanding of the pharmacological mechanisms underlying these biological effects. MATERIALS AND METHODS: To verify the gastroprotective properties rats were treated with AEUt (30, 60, or 120 mg/kg) prior to inducing gastric ulceration with ethanol or piroxicam. Additionally, the involvement of nitric oxide, non-protein sulfhydryl compounds (NP-SH), α-2 adrenergic receptors, and prostaglandins was investigated. Furthermore, a pylorus ligature model was employed to investigate the antisecretory activity of AEUt. The gastric healing effects of AEUt (60 mg/kg) were examined in rats in which ulceration had been induced with 80% acetic acid, whereas the quality of healing was evaluated in mice with interleukin-induced recurrent ulcers. We also evaluated the in vivo thickness of the gastric wall using ultrasonography. Moreover, the levels of reduced glutathione (GSH) and malondialdehyde (MDA) were evaluated in ulcerated mucosa, and we determined the activities of the enzymes myeloperoxidase (MPO), N-acetyl-ß-D-glycosaminidase, superoxide dismutase, catalase, and glutathione S-transferase. In addition, we assessed the effects of AEUt on cell viability and subjected the AEUt to phytochemical analyses. RESULTS: Administration of the AEUt (60 or 120 mg/kg) prevented ethanol- and piroxicam-induced ulceration, which was also confirmed histologically. Moreover, we observed that pre-treatment with NEM and indomethacin abolished the gastroprotective effects of AEUt, thereby indicating the involvement of NP-SH and prostaglandins in these protective effects. In addition, we found that the administration of AEUt had no appreciable effects on the volume, acidity, or peptic activity of gastric juice. Furthermore, the AEUt (60 mg/kg) accelerated the gastric healing of acetic acid-induced ulcers by 46.2% and ultrasonographic findings revealed a reduction in the gastric wall thickness in this group. The gastric healing effect of AEUt was also accompanied by a reduction in MPO activity. The AEUt (60 mg/kg) also minimized ulcer recurrence in mice exposed to IL-1ß and was associated with the maintenance of GSH levels and a reduction in MDA contents. We deduce that the biological effects of AEUt could be associated with the activities of polyphenols and the alkaloids isomitraphylline and mitraphylline, identified as predominant constituents of the AEUt. Furthermore, we found no evidence to indicate that AEUt would have any cytotoxic effects. CONCLUSION: Collectively, our findings provide compelling evidence indicating the therapeutic efficacy of U. tomentosa. Our data indicate that compounds in AEUt confer gastroprotection and that this preventive effect of AEUt was accompanied by gastric healing and a reduction in gastric ulcer recurrence. Moreover, we provide evidence to indicate that the gastroprotective and gastric healing effects involve the antioxidant system and anti-inflammatory responses that contribute to preserving the gastric mucosa.

Predicting the future of threatened birds from a Neotropical ecotone area.

Climate change affects ecosystems in different ways. These effects are particularly worrying in the Neotropical region, where species are most vulnerable to these changes because they live closer to their thermal safety limits. Thus, establishing conservation priorities, particularly for the definition of protected areas (PAs), is a priority. However, some PA systems within the Neotropics are ineffective even under the present environmental conditions. Here, we test the effectiveness of a PA system, within an ecotone in northern Brazil, in protecting 24 endangered bird species under current and future (RCP8.5) climatic scenarios. We used species distribution modeling and dispersal corridor modeling to describe the priority areas for conservation of these species. Our results indicate that several threatened bird taxa are and will potentially be protected (i.e., occur within PAs). Nonetheless, the amount of protected area is insufficient to maintain the species in the ecotone. Moreover, most taxa will probably present drastic declines in their range sizes; some are even predicted to go globally extinct soon. Thus, we highlight the location of a potentially effective system of dispersal corridors that connects PAs in the ecotone. We reinforce the need to implement public policies and raise public awareness to maintain PAs and mitigate anthropogenic effects within them, corridors, and adjacent areas, aiming to conserve the richness and diversity of these already threatened species.

Evaluation of the hydroalcoholic extract of Clarisia racemosa as an antiparasitic agent: an in vitro approach.

Clarisia racemosa Ruiz & Pav is a neotropical species found in humid forests from southern Mexico to southern Brazil. There are few studies related to the ethnopharmacological use of C. racemosa. Our objective was to evaluate the hydroalcoholic extract of C. racemosa as a potential antiparasitic agent. For this, we performed in vitro assays against strains of Leishmania amazonensis, Trypanosoma cruzi, Plasmodium falciparum, and Schistosoma mansoni. At the same time, immunomodulatory activity tests were carried out. The results demonstrated that the extract was able to stimulate and activate immune cells. In preliminary antiparasitic tests, structural modifications were observed in the promastigote form of L. amazonensis and in adult worms of S. mansoni. The extract was able to inhibit the growth of trypomastigote form of T. cruzi and finally showed low antiparasitic activity against strains of P. falciparum. It is pioneering work and these results demonstrate that C. racemosa extract is a promising alternative and contributes to the arsenal of possible forms of treatment to combat parasites. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03799-2.

Climate change in the Central Amazon and its impacts on frog populations.

Frog population declines have already been observed in the central Amazon even for common species that are considered not to be in danger of extinction. The Amazon is close to its limit of tolerated deforestation, and parts of the forest have already been modified by climate change, which raises questions about how the fauna in these areas would adapt to climate changes by the middle and the end of this century. In this study we used population density data on seven species of Amazonian frogs and analyzed the relationship between the activity of these species and temperature, precipitation, and relative humidity. We also used the least-squares method with logarithmic models to assess whether climate change projected by the Intergovernmental Panel on Climate Change (IPCC) would be an indicator of the population dynamics of these species. Our results suggest that even common species may be may experience population declines and extinction in the next decades due to climate changes.

Taxonomic Contributions on Macrogynoplax Enderlein and Enderleina Jewett (Plecoptera: Perlidae) from Brazil, Including a New Species Supported by Molecular and Morphological Data.

Stoneflies (Plecoptera) are aquatic insects widely used in ecological and monitoring studies as indicators of environmental quality due to their high sensitivity to pollution. Among Brazilian Plecoptera, Perlidae is the most diverse family, with four genera (Anacroneuria Klapálek 1909, Enderleina Jewett 1960, Kempnyia Klapálek 1914, and Macrogynoplax Enderlein 1909) and about 150 species. Herein, based on data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) gene and morphological characters, we studied specimens of Enderleina and Macrogynoplax, mainly from the Brazilian Savanna. Our alignment with a total length of 608 base pairs included 23 COI sequences, of which 10 are new and 13 were obtained from GenBank. The sequences and congruence of the obtained species clusters were analyzed using neighbor joining. As a result, we describe a new species of Enderleina, the first of this genus in the Brazilian Savanna, and update the geographic distribution of some Macrogynoplax species. A new record was included for Macrogynoplax veneranda Froehlich 1984 in São Paulo state and the first record of M. yupanqui Stark 1996 in Brazil was also included. First records were made for Macrogynoplax matogrossensis Bispo and Neves 2005 and a Macrogynoplax specimen in Goiás and Bahia states, respectively. Consequently, we expanded the distribution of the genus in the Brazilian Savanna and Atlantic Forest. In addition, we provide observations on the morphological differences found among these species, discuss about the distribution of the genera, present molecular data discussing their contributions to the knowledge of the genus, and comment on the recommendations for future research considering a scenario of integrative approaches. Lastly, we present a key to identify the adult males of Enderleina.

Seropositivity of Anti-Toxoplasma gondii and Anti-Neospora caninum Antibodies in Cattle Intended for Human Consumption in an Amazonian Area of North Brazil.

Toxoplasma gondii and Neospora caninum are obligate intracellular intestinal coccidia distributed worldwide, and are causative agents of toxoplasmosis and neosporosis, respectively. The aim of this study was to evaluate the prevalence of anti-T. gondii and anti-N. caninum antibodies and the factors associated with infections in beef cattle intended for human consumption in an Amazonian area of North Brazil. We collected blood samples of 387 cattle from 50 herds located in different municipalities of the State of Rondônia. An epidemiological questionnaire was distributed to farmers, with regard to nutritional, sanitary and reproductive herd management. The samples were identified, refrigerated and sent for serological analyses via IFAT (Immunofluorescent Antibody Test). Among the 387 analyzed animals, 91 (23.5%; CI 95%: 18.8-27.2) were positive for anti-T. gondii antibodies, with titers varying from 1:64 (75.8%) to 1:512 (2.2%). For anti-N. caninum antibodies, only four animals (1%; CI 95%: 0-2.7) were positive, with titers ranging from 1:400 (50%) to 1:1600 (25%). We observed a significant rate of anti-T. gondii antibodies in the variables "pure breed" and "contact with free-range chickens" (p < 0.2). There were no risk factors associated with the presence of anti-T. gondii or anti-N. caninum antibodies. In conclusion, there was a high prevalence of anti-T. gondii antibodies in beef cattle intended for human consumption in the State of Rondônia, Brazil, and a low prevalence of anti-N. caninum antibodies. Longitudinal studies can better elucidate the cause of these prevalence levels and how they could be better prevented and controlled.

DNA Barcodes of Mansonia (Mansonia) Blanchard, 1901 (Diptera, Culicidae).

Females of the genus Mansonia feed on the blood of humans, livestock, and other vertebrates to develop their eggs. The females' biting behavior may cause severe disturbance to blood hosts, with a negative impact on public health and economics. Certain species have been identified as potential or effective disease vectors. The accurate species identification of field-collected specimens is of paramount importance for the success of monitoring and control strategies. Mansonia (Mansonia) morphological species boundaries are blurred by patterns of intraspecific heteromorphism and interspecific isomorphism. DNA barcodes can help to solve taxonomic controversies, especially if combined with other molecular tools. We used cytochrome c oxidase subunit I (COI) gene 5' end (DNA barcode) sequences to identify 327 field-collected specimens of Mansonia (Mansonia) spp. The sampling encompassed males and females collected from three Brazilian regions and previously assigned to species based on their morphological characteristics. Eleven GenBank and BOLD sequences were added to the DNA barcode analyses. Initial morphospecies assignments were mostly corroborated by the results of five clustering methods based on Kimura two-parameter distance and maximum likelihood phylogeny. Five to eight molecular operational taxonomic units may represent taxonomically unknown species. The first DNA barcode records for Mansonia fonsecai, Mansonia iguassuensis, and Mansonia pseudotitillans are presented.

Treehoppers (Hemiptera, Auchenorrhyncha: Aetalionidae and Membracidae) from western Acre, Brazil, with emphasis on the fauna of Serra do Divisor National Park / Soldadinhos (Hemiptera, Auchenorrhyncha: Aetalionidae e Membracidae) do extremo oeste do Acre, Brasil, com ênfase na fauna do Parque Nacional Serra do Divisor

Abstract The first list of Aetalionidae and Membracidae species for western Acre is presented, including the Alto do Juruá regions of Serra do Divisor National Park and the Campus Floresta of the Federal University of Acre. In total, 94 species of treehoppers were collected, of which Centrotinae (Membracidae) is recorded for the first time for Brazil (Abelus maculatus Schimidt), another 16 species are new Brazilian records, and 69 species (Aetalionidae and Membracidae) are new records for Acre. Data on type locality, geographic distribution and images of all species are presented. The males of Lophyraspis fenestrata Sakakibara & Creão-Duarte and Erechtia sanguinolenta (Fairmaire) are known for the first time. The species diversity was compared to four other treehopper surveys in the Amazon region, with similarity indices of about 43.6% for Colombian Amazon (at least 650 km away), 27.6% for Panguana Biological Research Station, Peru (250 km), 20.2% for Adolpho Ducke Forest Reserve, Brazil (1,600 km) and 8.5% for Villa Carmen Biological Station/Los Amigos Biological Station, Peru (600/700 km). The estimated richness of Serra do Divisor National Park was just over 70%, suggesting that local diversity could be significantly higher than that presented in this study.

Resumo A primeira lista de espécies de Aetalionidae e Membracidae para o extremo oeste do Acre é apresentada, incluindo as regiões do Alto do Juruá do Parque Nacional da Serra do Divisor e o Campus Floresta da Universidade Federal do Acre. No total, foram coletadas 94 espécies de soldadinhos, das quais Centrotinae (Membracidae) é registrada pela primeira vez para o Brasil (Abelus maculatus Schimidt), 16 outras espécies de membracídeos são novos registros para o Brasil e 69 espécies (Aetalionidae e Membracidae) são novos registros para o Acre. Dados sobre localidade-tipo, distribuição geográfica e imagens de todas as espécies são apresentados. Os machos de Lophyraspis fenestrata Sakakibara & Creão-Duarte e Erechtia sanguinolenta (Fairmaire) são conhecidos pela primeira vez. A diversidade de espécies foi comparada a outros quatro levantamentos de soldadinhos na região amazônica, com índices de similaridade de cerca de 43,6% para a Amazônia colombiana (pelo menos 650 km de distância), 27,6% para a Estação de Pesquisa Biológica de Panguana, Peru (250 km), 20,2% para Adolpho Reserva Florestal Ducke, Brasil (1.600 km) e 8,5% para Estação Biológica Villa Carmen/Estação Biológica Los Amigos, Peru (600/700 km). A riqueza estimada do Parque Nacional da Serra do Divisor foi de pouco mais de 70%, sugerindo que a diversidade local pode ser significativamente maior do que a apresentada neste estudo.

Impact of Malakit intervention on perceptions, knowledge, attitudes, and practices related to malaria among workers in clandestine gold mines in French Guiana: results of multicentric cross-sectional surveys over time.

BACKGROUND: Clandestine gold miners remain key hosts for malaria in French Guiana (FG) and contribute to imported malaria cases in Suriname and Brazil. The Malakit intervention, implemented in FG borders with Suriname and Brazil, provided gold miners with training on malaria and kits for self-diagnosis and self-treatment. Having shown a likely impact on malaria transmission, Suriname has now implemented it in routine care for cross-border moving populations. However, a decrease in malaria transmission is frequently associated with a decrease in risk perception, knowledge, and good practices regarding malaria. This study aims to describe the evolution of the perceptions, knowledge, attitudes, and practices (KAP) related to malaria among clandestine gold miners between 2015 and 2019, and to estimate the impact of Malakit on the FG/Suriname border. METHODS: The primary outcome was the overall KAP score over time and among participants and not participants in the Malakit intervention. A propensity score matching analysis and an inverse probability of treatment weighing analysis were used to estimate the Average Treatment effect on the Treated and the Average Treatment Effect of Malakit, respectively. RESULTS: Perception and knowledge scores were significantly lower in 2019 compared to 2015 (- 0.27 and - 0.23 points, respectively, p < 0.001) while attitude and practice scores were higher (+ 0.16 and + 0.47 points, respectively, p < 0.001). The overall KAP score was significantly higher among participants in Malakit with both propensity score matching (+ 0.72 points, 95%IC [0.29; 1.15]) and inverse probability of treatment weighting analysis (+ 0.70 points, 95%IC [0.34; 1.05]). CONCLUSION: A decrease in perception and knowledge about malaria but an improvement of attitudes and practices as the incidence of malaria decreased are observed. The Malakit intervention seems to have a significant positive impact on the overall KAP related to malaria. The integration of this strategy into malaria control programmes could help to improve the KAP, even in areas where malaria is nearly eliminated, through optimal training and health empowerment. Trial registration ClinicalTrials.gov registration number: NCT03695770.

Feedback in tropical forests of the Anthropocene.

Tropical forests are complex systems containing myriad interactions and feedbacks with their biotic and abiotic environments, but as the world changes fast, the future of these ecosystems becomes increasingly uncertain. In particular, global stressors may unbalance the feedbacks that stabilize tropical forests, allowing other feedbacks to propel undesired changes in the whole ecosystem. Here, we review the scientific literature across various fields, compiling known interactions of tropical forests with their environment, including the global climate, rainfall, aerosols, fire, soils, fauna, and human activities. We identify 170 individual interactions among 32 elements that we present as a global tropical forest network, including countless feedback loops that may emerge from different combinations of interactions. We illustrate our findings with three cases involving urgent sustainability issues: (1) wildfires in wetlands of South America; (2) forest encroachment in African savanna landscapes; and (3) synergistic threats to the peatland forests of Borneo. Our findings reveal an unexplored world of feedbacks that shape the dynamics of tropical forests. The interactions and feedbacks identified here can guide future qualitative and quantitative research on the complexities of tropical forests, allowing societies to manage the nonlinear responses of these ecosystems in the Anthropocene.

Changes in leaf functional traits with leaf age: when do leaves decrease their photosynthetic capacity in Amazonian trees?

Most leaf functional trait studies in the Amazon basin do not consider ontogenetic variations (leaf age), which may influence ecosystem productivity throughout the year. When leaf age is taken into account, it is generally considered discontinuous, and leaves are classified into age categories based on qualitative observations. Here, we quantified age-dependent changes in leaf functional traits such as the maximum carboxylation rate of ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) (Vcmax), stomatal control (Cgs%), leaf dry mass per area and leaf macronutrient concentrations for nine naturally growing Amazon tropical trees with variable phenological strategies. Leaf ages were assessed by monthly censuses of branch-level leaf demography; we also performed leaf trait measurements accounting for leaf chronological age based on days elapsed since the first inclusion in the leaf demography, not predetermined age classes. At the tree community scale, a nonlinear relationship between Vcmax and leaf age existed: young, developing leaves showed the lowest mean photosynthetic capacity, increasing to a maximum at 45 days and then decreasing gradually with age in both continuous and categorical age group analyses. Maturation times among species and phenological habits differed substantially, from 8 ± 30 to 238 ± 30 days, and the rate of decline of Vcmax varied from -0.003 to -0.065 µmol CO2 m-2 s-1 day-1. Stomatal control increased significantly in young leaves but remained constant after peaking. Mass-based phosphorus and potassium concentrations displayed negative relationships with leaf age, whereas nitrogen did not vary temporally. Differences in life strategies, leaf nutrient concentrations and phenological types, not the leaf age effect alone, may thus be important factors for understanding observed photosynthesis seasonality in Amazonian forests. Furthermore, assigning leaf age categories in diverse tree communities may not be the recommended method for studying carbon uptake seasonality in the Amazon, since the relationship between Vcmax and leaf age could not be confirmed for all trees.

Small understorey trees have greater capacity than canopy trees to adjust hydraulic traits following prolonged experimental drought in a tropical forest.

Future climate change predictions for tropical forests highlight increased frequency and intensity of extreme drought events. However, it remains unclear whether large and small trees have differential strategies to tolerate drought due to the different niches they occupy. The future of tropical forests is ultimately dependent on the capacity of small trees (<10 cm in diameter) to adjust their hydraulic system to tolerate drought. To address this question, we evaluated whether the drought tolerance of neotropical small trees can adjust to experimental water stress and was different from tall trees. We measured multiple drought resistance-related hydraulic traits across nine common neotropical genera at the world's longest-running tropical forest throughfall-exclusion experiment and compared their responses with surviving large canopy trees. Small understorey trees in both the control and the throughfall-exclusion treatment had lower minimum stomatal conductance and maximum hydraulic leaf-specific conductivity relative to large trees of the same genera, as well as a greater hydraulic safety margin (HSM), percentage loss of conductivity and embolism resistance, demonstrating that they occupy a distinct hydraulic niche. Surprisingly, in response to the drought treatment, small trees increased specific hydraulic conductivity by 56.3% and leaf:sapwood area ratio by 45.6%. The greater HSM of small understorey trees relative to large canopy trees likely enabled them to adjust other aspects of their hydraulic systems to increase hydraulic conductivity and take advantage of increases in light availability in the understorey resulting from the drought-induced mortality of canopy trees. Our results demonstrate that differences in hydraulic strategies between small understorey and large canopy trees drive hydraulic niche segregation. Small understorey trees can adjust their hydraulic systems in response to changes in water and light availability, indicating that natural regeneration of tropical forests following long-term drought may be possible.

The butterflies of Cristalino Lodge, in the Brazilian southern Amazonia: An updated species list with a significant contribution from citizen science / As borboletas do Cristalino Lodge, no sul da Amazônia: Uma lista atualizada de espécies com contribuição significativa da ciência cidadã

Abstract The richest butterfly communities in the world are found in the Amazon rainforest. Despite of this, and the importance of species inventories for the knowledge of diversity patterns, there are few comprehensive lists of butterflies for localities in the Brazilian Amazon. Here, we present an updated list of the butterflies of Cristalino Lodge (Alta Floresta, Mato Grosso, Brazil), in southern Amazonia, based on specimens collected by researchers and photographic records taken by ecotourists, butterfly watchers, and tour guides. With 1010 species recorded, this is currently the largest list of butterflies published for a single locality in Brazil and the first to reach (and surpass) 1000 species, with more than one third of the records coming from citizen science. The region has about 29% of the butterfly species in Brazil and one of the greatest richnesses known in the country, inferior only to areas in the western Amazon. Its fauna is mainly composed of species widely distributed in lowland Amazonia, with the addition of some species typical of the Cerrado. It has a relatively low number of species of the tribe Ithomiini (Nymphalidae: Danainae), generally considered a good indicator of the total butterfly diversity in neotropical forests, which points to the need for caution when using a single taxonomic group as a surrogate of richness of entire communities. The present work highlights the importance of citizen science and ecotourism centers for inventories and data on species distribution in diverse tropical forests.

Resumo As comunidades de borboletas mais ricas do mundo são encontradas na Amazônia. Apesar disso, e da importância dos inventários de espécies para o conhecimento dos padrões de diversidade, existem poucas listas abrangentes de borboletas para localidades da Amazônia brasileira. Aqui, apresentamos uma lista atualizada das borboletas do Cristalino Lodge (Alta Floresta, Mato Grosso, Brasil), no sul da Amazônia, baseada em espécimes coletados por pesquisadores e em registros fotográficos feitos por ecoturistas, observadores de borboletas e guias turísticos. Com 1010 espécies registradas, essa é atualmente a maior lista de borboletas publicada para uma localidade no Brasil e a primeira a atingir 1000 espécies, sendo mais de um terço dos registros provenientes da ciência cidadã. A região apresenta cerca de 29% das espécies de borboletas do Brasil e uma das maiores riquezas conhecidas no país, inferior apenas a áreas no oeste da Amazônia. Sua fauna é composta principalmente por espécies amplamente distribuídas na planície amazônica, com adição de algumas típicas do Cerrado. Possui um número relativamente baixo de espécies da tribo Ithomiini (Nymphalidae: Danainae), que é geralmente considerada uma boa indicadora da riqueza total de borboletas em florestas neotropicais, o que aponta para a necessidade de cautela ao se usar um grupo taxonômico como previsor da riqueza de comunidades inteiras. O presente trabalho destaca a importância da ciência cidadã e dos centros de ecoturismo para inventários e dados sobre distribuição de espécies em florestas tropicais diversas.

Forest fires and deforestation in the central Amazon: Effects of landscape and climate on spatial and temporal dynamics.

Forest fires and deforestation are the main threats to the Amazon forest. Extreme drought events exacerbate the impact of forest fire in the Amazon, and these drought events are predicted to become more frequent due to climate change. Fire escapes into the forest from agriculture and pasture areas. We assessed the potential drivers of deforestation and forest fires in the central Brazilian Amazon and show that over a period of 31 years (1985-2015) forest fires occurred only in years of extreme drought induced by El Niño (1997, 2009 and 2015). The association of forest fires with strong El Niños shows the vulnerability of forest to climate change. The areas deforested were closely associated with navigable rivers: 62% of the total deforestation from 2000 to 2018 was located within the 2 km of rivers. There was a notable increase in deforestation and forest fire during the 2015 El Niño in comparison to previous years. Only a small part of the forest that burned was deforested in the years following the wildfires: 7% (1997), 3% (2009) and 1.5% (2015). Forest close to roads, rivers and established deforestation is susceptible to deforestation and fire since these areas are attractive for agriculture and pasture. Indigenous land was shown to be important in protecting the forest, while rural settlement projects attracted both forest fire and deforestation. Of the total area in settlement projects, 40% was affected by forest fires and 17% was deforested. Rivers are particularly important for deforestation in this part of Amazonia, and efforts to protect forest along the rivers are therefore necessary. The ability to predict where deforestation and fires are most likely to occur is important for designing policies for preventative actions.

Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation.

In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land-atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin.

Culturable bacteria associated with Anopheles darlingi and their paratransgenesis potential.

BACKGROUND: Malaria remains a major public health problem in South America, mostly in the Amazon region. Among newly proposed ways of controlling malaria transmission to humans, paratransgenesis is a promising alternative. Paratransgenesis aims to inhibit the development of parasites within the vector through the action of genetically modified bacteria. The first step towards successful paratransgenesis in the Amazon is the identification of Anopheles darlingi symbiotic bacteria, which are transmitted vertically among mosquitoes, and are not pathogenic to humans. METHODS: Culturable bacteria associated with An. darlingi and their breeding sites were isolated by conventional microbiological techniques. Isolated strains were transformed with a GFP expressing plasmid, pSPT-1-GFP, and reintroduced in mosquitoes by feeding. Their survival and persistence in the next generation was assessed by the isolation of fluorescent bacteria from eggs, larvae, pupae and adult homogenates. RESULTS: A total of 179 bacterial strains were isolated from samples from two locations, Coari and Manaus. The predominant genera identified in this study were Acinetobacter, Enterobacter, Klebsiella, Serratia, Bacillus, Elizabethkingia, Stenotrophomonas and Pantoea. Two isolated strains, Serratia-Adu40 and Pantoea-Ovo3, were successfully transformed with the pSPT-1-GFP plasmid and expressed GFP. The fluorescent bacteria fed to adult females were transferred to their eggs, which persisted in larvae and throughout metamorphosis, and were detected in adult mosquitoes of the next generation. CONCLUSION: Serratia-Adu40 and Pantoea-Ovo3 are promising candidates for paratransgenesis in An. darlingi. Further research is needed to determine if these bacteria are vertically transferred in nature.

Competition indices after reduced impact logging in the Brazilian Amazon.

Competition for resources can affect growth and increase mortality in forest stands. The effects of this process are little known, especially in areas subjected to forest management which show distinct growth dynamics when compared to unmanaged natural areas. This study aimed to estimate, evaluate and select the best fit competition indices (CI) for individual trees in a managed forest in the eastern Amazon. The data used originated from 18 permanent plots of 1 ha each, which were monitored for 12 years after Reduced Impact Logging (RIL). For the competition analysis, 23 indices were tested. CIs were evaluated based on graphical analyses and linear correlation coefficients(r)between each index and variables, basal area growth(ΔG), probability of mortality(Pm), and post-logging period (PLP). In addition, the partial F-test was applied to verify how well the calculated CIs explain the variations observed in ΔGandP(m). The distance-independent index for BAL (Basal Area Larger) performed the best. For the distance-dependent and semi-independent indices, the best interactions with the variables tested occurred in radii of 15 and 20 m away from the object tree. The largest trees presented higher values ofΔG. While P(m)was similar among the three tree classes, larger trees had a slightly higher P(m)due to thier low density of individuals. The results obtained in this study may help to include CIs in growth and production models at the individual tree level in tropical rainforests, especially in those managed in the Brazilian Amazon.

Self-diagnosis and self-treatment of malaria in hard-to-reach and mobile populations of the Amazon: results of Malakit, an international multicentric intervention research project.

Background: Illegal gold miners are currently key hosts for malaria in French Guiana (FG), with a risk of emergence of resistance linked to improper use of artemisinin-based combination therapy (ACT). The remoteness of the mines and regulatory issues hinder their access to health care. Methods: A quasi-experimental researched project (Malakit) implemented in FG borders with Brazil and Suriname aimed at determining the effectiveness of distributed kits for self-diagnosis and self-treatment to illegal gold miners, after training, at strategic border staging areas. Evaluation relied on questionnaires at inclusion and follow-up visits, and pre/post intervention surveys. The primary outcome was the proportion of persons reporting a use of certified ACT after a positive malaria diagnosis. The secondary outcomes assessed antimalarial adherence, kit use and impact on malaria epidemiology. Findings: The proportion of patients reporting a use of certified ACT after a positive diagnosis increased after the intervention (OR 1.8, 95%CI [1.1-3.0]). From April 2018 to March 2020, 3,733 persons participated in the intervention. The kit was used correctly by 71.7% [65.8-77.7] of the 223 persons reporting having used a malakit during the follow-up visits. No serious adverse events related to the misuse of malakit have been reported. The intervention appears to have accelerated the decline in malaria incidence in the region by 42.9%. Interpretation: This innovative international project showed that people with low education can correctly self-manage their malaria symptoms. This strategy could be integrated in the malaria control programs of the countries involved and considered in other regions with residual malaria in remote areas. Funding: This project was funded by the European Union, the Global Fund, Brazil MoH, Cayenne Hospital and FG Health Regional Agency. Editor's note: This translation in French was submitted by the authors and we reproduce it as supplied. It has not been peer reviewed. Our editorial processes have only been applied to the original abstract in English, which should serve as reference for this manuscript. The Lancet Group takes a neutral position with respect to territorial claims in published maps and institutional affiliations. Contexte: Les chercheurs d'or illégaux sont actuellement un réservoir clé du paludisme en Guyane, avec un risque d'émergence de résistance lié à une mauvaise utilisation des combinaisons thérapeutiques à base d'artémisinine (ACT). L'isolement de ces sites miniers clandestins et des contraintes règlementaires entravent leur accès aux soins. Méthodes: Un projet de recherche opérationnelle quasi-expérimental (Malakit) a été mis en œuvre aux frontières de la Guyane avec le Brésil et le Suriname. Il visait à déterminer l'efficacité de la distribution de kits d'autodiagnostic et d'autotraitement à des orpailleurs illégaux, après une formation adaptée, dans des zones stratégiques transfrontalières. L'évaluation s'est appuyée sur des questionnaires lors des visites d'inclusion et de suivi, et sur des enquêtes pré/post intervention. L'indicateur principal était la proportion de personnes déclarant avoir utilisé une ACT certifiée après un diagnostic positif de paludisme. Les indicateurs secondaires reposaient sur l'adhérence aux traitements antipaludiques, l'utilisation des kits et l'impact sur l'épidémiologie du paludisme. Résultats: La proportion de patients déclarant une utilisation d'ACT certifiée après un diagnostic positif a augmenté après l'intervention (OR 1,8, 95%CI [1,1-3,0]). D'avril 2018 à mars 2020, 3 733 personnes ont participé à l'intervention. Le kit a été utilisé correctement par 71,7% [65,8-77,7] des 223 personnes revues en visites de suivi ayant déclaré avoir utilisé un malakit. Aucun événement indésirable grave lié à une mauvaise utilisation du malakit n'a été signalé. L'intervention semble avoir accéléré la diminution de l'incidence du paludisme dans la région de 42,9%. Interprétation: Ce projet international innovant a montré que les personnes ayant un faible niveau d'éducation peuvent se prendre en charge par eux-mêmes pour des symptômes de paludisme. Cette stratégie pourrait être intégrée dans les programmes de lutte contre le paludisme des pays impliqués et envisagée dans d'autres régions où du paludisme résiduel persiste dans des zones isolées. Financement: Ce projet a été financé par l'Union Européenne, le Fonds Mondial, le Ministère de la santé du Brésil, le Centre Hospitalier de Cayenne et l'Agence Régionale de Santé de Guyane.

The Amazonian luminescent Mycena cristinae sp. nov. from Brazil.

A new luminescent lignicolous fungal species, Mycena cristinae sp. nov., is proposed from the Central Amazon forest. This is unique and supported by morphological evaluation along with LSU- and ITS-based phylogenetic analyses. The basidiomata have mostly fuscous olivaceous brown pileus, adnate to subdecurrent and distant lamellae, and stipe with slightly bulbous base (basal mycelium absent). It also has inamyloid and/or weakly amyloid basidiospores, ramose cheilocystidia and a pileipellis composed of an aerated tangle of slender, diverticulate hyphae forming a coralloid pellicle overlaying the hypodermium. The luminescence is evident in the basidiomata (especially the stipe) and in the mycelium on the substrate. The LSU phylogenetic trees reveal that M. cristinae is sister to M. coralliformis within the Mycenaceae clade. In the ITS trees, it forms a unique lineage grouping with undetermined Mycena taxa. Morphological data support M. cristinae as a different species compared to previously described taxa.

Photosynthetic quantum efficiency in south-eastern Amazonian trees may be already affected by climate change.

Tropical forests are experiencing unprecedented high-temperature conditions due to climate change that could limit their photosynthetic functions. We studied the high-temperature sensitivity of photosynthesis in a rainforest site in southern Amazonia, where some of the highest temperatures and most rapid warming in the Tropics have been recorded. The quantum yield (Fv /Fm ) of photosystem II was measured in seven dominant tree species using leaf discs exposed to varying levels of heat stress. T50 was calculated as the temperature at which Fv /Fm was half the maximum value. T5 is defined as the breakpoint temperature, at which Fv /Fm decline was initiated. Leaf thermotolerance in the rapidly warming southern Amazonia was the highest recorded for forest tree species globally. T50 and T5 varied between species, with one mid-storey species, Amaioua guianensis, exhibiting particularly high T50 and T5 values. While the T50 values of the species sampled were several degrees above the maximum air temperatures experienced in southern Amazonia, the T5 values of several species are now exceeded under present-day maximum air temperatures.