The impact of grazing on biodiversity and forest succession in the Brazilian dry forest region is constrained by non-equilibrium dynamics.

The impacts of grazing on rangelands have historically been studied within the framework of the equilibrium model, which predicts significant impacts of grazing on ecosystems. However, in recent decades, studies have observed a non-equilibrium pattern, suggesting that abiotic factors play a primary role compared to grazing. These studies are primarily focused on rangelands, despite animal husbandry occurring in other biomes, such as seasonally dry tropical forests. Our study examines the influence of goat grazing on biodiversity and forest succession in the Brazilian dry forest (Caatinga). Considering its high interannual precipitation variability, we hypothesize a response that aligns with the non-equilibrium paradigm. We established a gradient of grazing intensity and history in areas at different stages of vegetation succession. A survey of tree - shrub and herbaceous species was conducted at each site and the biomass of both strata was quantified. Linear mixed models and Permanova were employed to assess differences in richness, composition, structure, and biomass among the areas. Our results suggest that grazing (history and intensity) and forest fallow age did not affect species richness, but only species composition. Low and high grazing intensity drive ecosystems toward similar compositions, which align with the non-equilibrium model predictions. Biomass in the herbaceous layer remained unaffected by grazing history, intensity, or forest fallow age, whereas woody biomass was influenced by grazing intensity in older forest fallows. Although trees in low-intensity grazing sites were significantly taller compared to those in other levels, overall, grazing did not disrupt the natural succession process. Older forest fallows exhibited greater diversity and higher basal area compared to new forest fallows, irrespective of grazing intensity. Our findings suggest that: a) grazing has minimal effects on biodiversity and biomass due to non-equilibrium dynamics, and b) with appropriate management, grazing can coexist with the conservation of the Caatinga.

Decompression Associated with Irrigation with Elixir Sanativo® Before Enucleation of Odontogenic Keratocysts: Report of Two Cases

Odontogenic Keratocyst (OKC) is an aggressive cystic lesion of the jaws and one of the most common odontogenic cysts, usually affecting the posterior region of the mandible. Recurrences are frequently recorded and may be directly related to the treatment modality adopted. Two patients presenting OKC were treated by combining decompression and intralesional irrigation with the drug Elixir Sanativo® for 8 months before enucleation surgery. In both patients, the association between decompression and irrigation with Elixir Sanativo® represented a safe and effective method to reduce the preoperative lesion dimensions.

El queratoquiste odontogénico (QO) es una lesión quística agresiva de la mandíbula y es uno de los quistes odontogénicos más frecuentes, que suele afectar a la región posterior de la mandíbula. Las recidivas se registran con frecuencia y pueden estar directamente relacionadas con la modalidad de tratamiento adoptada. Presentación del caso: Dos pacientes que presentaban OKC fueron tratados combinando descompresión e irrigación intralesional con el fármaco Elixir Sanativo® durante 8 meses antes de la cirugía de enucleación. En ambos pacientes, la asociación entre descompresión e irrigación con Elixir Sanativo® representó un método seguro y eficaz para reducir las dimensiones de la lesión preoperatoria.

Aerobic exercise attenuates dysautonomia, cardiac diastolic dysfunctions, and hemodynamic overload in female mice with atherosclerosis.

Cardiovascular risk increases during the aging process in women with atherosclerosis and exercise training is a strategy for management of cardiac risks in at-risk populations. Therefore, the aims of this study were to evaluate: (1) the influence of the aging process on cardiac function, hemodynamics, cardiovascular autonomic modulation, and baroreflex sensitivity in females with atherosclerosis at the onset of reproductive senescence; and (2) the impact of exercise training on age-related dysfunctions in this model. Eighteen Apolipoprotein-E knockout female mice were divided equally into young (Y), middle-aged (MA), and trained middle-aged (MAT). Echocardiographic exams were performed to verify cardiac morphology and function. Cannulation for direct recording of blood pressure and heart rate, and analysis of cardiovascular autonomic modulation, baroreflex sensitivity were performed. The MA had lower cardiac diastolic function (E'/A' ratio), and higher aortic thickness, heart rate and mean arterial pressure, lower heart rate variability and baroreflex sensitivity compared with Y. There were no differences between Y and MAT in these parameters. Positive correlation coefficients were found between aortic wall thickness with hemodynamics data. The aging process causes a series of deleterious effects such as hemodynamic overload and dysautonomia in female with atherosclerosis. Exercise training was effective in mitigating aged-related dysfunctions.

Experience with 808-nm diode laser in the treatment of 47 cases of oral vascular anomalies.

Treatment of oral vascular anomalies (OVA) has focused on minimally invasive techniques rather than radical surgery. We investigated the efficacy and safety of diode laser using the photocoagulation technique in the management of OVA. Forty-seven subjects with OVA were treated with forced dehydration with induced photocoagulation (FDIP) using diode laser (808 nm/4.5 W). This series consisted mostly of male (63.8%) and non-white (63.8%) patients with a mean age of 57.4 years. Varices (91.5%), venous malformations (6.4%), and hemangiomas (2.1%) with a mean size of 7.1 (±4.9) mm were the conditions treated. OVA presented as a nodular lesion (63.8%) involving mainly the lower lip (46.8%). Pulsed laser mode was used as standard and the number of applications varied from one to four sessions, with the majority requiring only one (83%) FDIP session. Kaplan-Meier analysis revealed that complete clinical healing can occur on the 15th day (n=9/29.5%), followed by the 20th (n=6/45.5%), and 30th (n=7/70.5%) days. Postoperative edema was observed in 31 (66%) patients, and recurrence of the lesion occurred in two (4.2%). Based on the data on complete clinical healing, minimal patient discomfort, and satisfactory esthetic results, we can confirm that FDIP by diode laser is a promising candidate for the safe and efficacious treatment of OVA.

Prevalence and antimicrobial resistance profile of pathogens isolated from patients with urine tract infections admitted to a university hospital in a medium-sized Brazilian city.

This study aimed to determine the antibiotic profile of microorganisms isolated from urine samples of patients with community urine tract infections (UTI) admitted to the University Hospital of the Federal University of Sao Carlos to support an appropriate local empirical treatment. A retrospective cross-sectional study was conducted from October 2018 to October 2020. Data from 1,528 positive urine cultures for bacterial pathogens and antibiograms were tabulated. Bacterial species prevalence and their resistance profile were analyzed and compared by sex and age. For Gram-negative fermenting bacteria, resistance rates were compared between patients with previous hospitalization and the total of infections caused by this group. For comparisons, the Chi-square test was performed, using Fisher's exact test when necessary (BioEstat program, adopting p ≤ 0.05). A multivariate analysis was applied to assess the effect of the studied variables in predicting multidrug resistance. Infections were more prevalent in women and older adults. Gram-negative bacteria represented 90.44% of total cultures. In both sexes, E. coli prevalence was significantly higher in adults compared with older adults (p < 0.0001). For several antibiotics, resistance rates were higher in the older adults compared with other ages and in patients with Gram-negative fermenting infections and previous hospitalization compared with the total of infections by this group of bacteria. The closer to the hospitalization, the higher the number of antibiotics with superior resistance rates. Resistance rates for aminoglycosides, carbapenems, ceftazidime, nitrofurantoin, piperacillin+tazobactam, and fosfomycin were less than 20%, considered adequate for empirical treatment. Only hospitalization in the previous 90 days was statistically significant in predicting infections by multidrug-resistant bacteria.

Prevalence and antimicrobial resistance profile of pathogens isolated from patients with urine tract infections admitted to a university hospital in a medium-sized Brazilian city

ABSTRACT This study aimed to determine the antibiotic profile of microorganisms isolated from urine samples of patients with community urine tract infections (UTI) admitted to the University Hospital of the Federal University of Sao Carlos to support an appropriate local empirical treatment. A retrospective cross-sectional study was conducted from October 2018 to October 2020. Data from 1,528 positive urine cultures for bacterial pathogens and antibiograms were tabulated. Bacterial species prevalence and their resistance profile were analyzed and compared by sex and age. For Gram-negative fermenting bacteria, resistance rates were compared between patients with previous hospitalization and the total of infections caused by this group. For comparisons, the Chi-square test was performed, using Fisher's exact test when necessary (BioEstat program, adopting p ≤ 0.05). A multivariate analysis was applied to assess the effect of the studied variables in predicting multidrug resistance. Infections were more prevalent in women and older adults. Gram-negative bacteria represented 90.44% of total cultures. In both sexes, E. coli prevalence was significantly higher in adults compared with older adults (p < 0.0001). For several antibiotics, resistance rates were higher in the older adults compared with other ages and in patients with Gram-negative fermenting infections and previous hospitalization compared with the total of infections by this group of bacteria. The closer to the hospitalization, the higher the number of antibiotics with superior resistance rates. Resistance rates for aminoglycosides, carbapenems, ceftazidime, nitrofurantoin, piperacillin+tazobactam, and fosfomycin were less than 20%, considered adequate for empirical treatment. Only hospitalization in the previous 90 days was statistically significant in predicting infections by multidrug-resistant bacteria.

Experience with 808-nm diode laser in the treatment of 47 cases of oral vascular anomalies

Abstract Treatment of oral vascular anomalies (OVA) has focused on minimally invasive techniques rather than radical surgery. We investigated the efficacy and safety of diode laser using the photocoagulation technique in the management of OVA. Forty-seven subjects with OVA were treated with forced dehydration with induced photocoagulation (FDIP) using diode laser (808 nm/4.5 W). This series consisted mostly of male (63.8%) and non-white (63.8%) patients with a mean age of 57.4 years. Varices (91.5%), venous malformations (6.4%), and hemangiomas (2.1%) with a mean size of 7.1 (±4.9) mm were the conditions treated. OVA presented as a nodular lesion (63.8%) involving mainly the lower lip (46.8%). Pulsed laser mode was used as standard and the number of applications varied from one to four sessions, with the majority requiring only one (83%) FDIP session. Kaplan-Meier analysis revealed that complete clinical healing can occur on the 15th day (n=9/29.5%), followed by the 20th (n=6/45.5%), and 30th (n=7/70.5%) days. Postoperative edema was observed in 31 (66%) patients, and recurrence of the lesion occurred in two (4.2%). Based on the data on complete clinical healing, minimal patient discomfort, and satisfactory esthetic results, we can confirm that FDIP by diode laser is a promising candidate for the safe and efficacious treatment of OVA.

Oral Rehabilitation of Marginal Maxillectomy Patient After Local Flap Reconstruction.

The treatment of oral cancer can lead to various oral complications, including oral defects, tissue deformation, and trismus in patients who have undergone oral cancer surgery with resection of any part of the maxillary. Restoring the ability to chew, swallow, and maintain esthetics is essential and a significant challenge. The aim of this study was to report a successful clinical case of preprosthetic surgery and prosthetic rehabilitation of a 65-year-old man who had undergone marginal maxillectomy, resulting in tissue scarring and a significant reduction in maximal mouth opening. The oral rehabilitation was achieved using a conventional removable prosthesis. This case demonstrates that preprosthetic surgery combined with conventional removable prosthesis is an effective strategy for complex rehabilitations providing functional and esthetic improvement in the affected area for patients with marginal maxillectomies resulting from oral cancer.

Mannose-Binding Lectins as Potent Antivirals against SARS-CoV-2.

The SARS-CoV-2 entry into host cells is mainly mediated by the interactions between the viral spike protein (S) and the ACE-2 cell receptor, which are highly glycosylated. Therefore, carbohydrate binding agents may represent potential candidates to abrogate virus infection. Here, we evaluated the in vitro anti-SARS-CoV-2 activity of two mannose-binding lectins isolated from the Brazilian plants Canavalia brasiliensis and Dioclea violacea (ConBR and DVL). These lectins inhibited SARS-CoV-2 Wuhan-Hu-1 strain and variants Gamma and Omicron infections, with selectivity indexes (SI) of 7, 1.7, and 6.5, respectively for ConBR; and 25, 16.8, and 22.3, for DVL. ConBR and DVL inhibited over 95% of the early stages of the viral infection, with strong virucidal effect, and also protected cells from infection and presented post-entry inhibition. The presence of mannose resulted in the complete lack of anti-SARS-CoV-2 activity by ConBR and DVL, recovering virus titers. ATR-FTIR, molecular docking, and dynamic simulation between SARS-CoV-2 S and either lectins indicated molecular interactions with predicted binding energies of -85.4 and -72.0 Kcal/Mol, respectively. Our findings show that ConBR and DVL lectins possess strong activities against SARS-CoV-2, potentially by interacting with glycans and blocking virus entry into cells, representing potential candidates for the development of novel antiviral drugs.

HDAC3 inhibition protects against peripheral and central alterations in an animal model of obesity.

BACKGROUND: Obesity is a multifactorial disease with epigenetic manifestations that increases the prevalence of associated comorbidities such as metabolic syndrome, cardiovascular dysfunction, and major depression disorder. Given the aforementioned, a search for new pharmacological alternatives for the treatment of this disease is necessary. The current study aimed to evaluate the effects of histone deacetylase-3 (HDAC3) inhibition caused by RGFP966 (a benzamide-type HDAC inhibitor selective for HDAC3) administration, in an animal model of obesity induced by high-fat diet (HFD). METHODS: Adult male mice C57BJ/6 were fed with a normal pellet diet (NPD) or HFD for 120 days. The HDAC3 inhibitor (RGFP966; 10 mg/kg; sc) was administered on the 91st to 120th day of the experiment (per 30 days). After the last inhibitor administration, animals were euthanized, blood was collected, and the hippocampus was removed for biochemical determinations. RESULTS: In an overall manner, the administration of RGFP966 protected against changes in body weight gain, glucose, insulin, lipid profile, adipokines, and increase of hippocampal proinflammatory cytokines levels caused by HFD. CONCLUSION: Therefore, HDAC3 inhibition can represent a promising pharmacological target for the treatment of obesity.

Accidental Intraoperative Mandibular Fracture in a Third Molar Surgery: When Surgical Skills Are Mandatory in the Face of Empiricism.

Iatrogenic mandible fractures are rare complications from third molar removal surgeries. While most documented cases stress risk factors inherent to the patient and tooth presentation in fractures' etiology, appreciation of the risk factors underlying the practitioner's skills is scarce. Here, we describe an intraoperative fracture in a healthy 26-year-old female resulting from an incompatible surgical technique during the right mandibular third molar removal. The patient showed facial swelling, pain, malocclusion, and significant mobility of the fractured segment. The surgical management involved an intraoral open reduction with the installation of titanium plates for the fixation of the bone segments. Thus, we highlight that acknowledging the extent of the operator's surgical skills should be part of comprehensive treatment planning, serving as a valuable measure to prevent iatrogenic mandible fractures besides avoiding a traumatic experience for the patient.

Technical comparison of MinIon and Illumina technologies for genotyping Chikungunya virus in clinical samples.

New-generation sequencing (NGS) techniques have brought the opportunity for genomic monitoring of several microorganisms potentially relevant to public health. The establishment of different methods with different mechanisms provides a wide choice, taking into account several aspects. With that in mind, the present aim of the study was to compare basic genomic sequencing metrics that could potentially impact genotyping by nanopores from Oxford Nanopore Technologies and by synthesis from Illumina in clinical samples positive for Chikungunya (CHIKV). Among the metrics studied, running time, read production, and Q score were better represented in Illumina sequencing, while the MinIOn platform showed better response time and greater diversity of generated files. That said, it was possible to establish differences between the studied metrics in addition to verifying that the distinctions in the methods did not impact the identification of the CHIKV virus genotype.

Meta-omics integration approach reveals the effect of soil native microbiome diversity in the performance of inoculant Azospirillum brasilense.

Plant growth promoting bacteria (PGPB) have been used as integrative inputs to minimize the use of chemical fertilizers. However, a holistic comprehension about PGPB-plant-microbiome interactions is still incipient. Furthermore, the interaction among PGPB and the holobiont (host-microbiome association) represent a new frontier to plant breeding programs. We aimed to characterize maize bulk soil and rhizosphere microbiomes in irradiated soil (IS) and a native soil (NS) microbial community gradient (dilution-to-extinction) with Azospirillum brasilense Ab-V5, a PGPB commercial inoculant. Our hypothesis was that plant growth promotion efficiency is a result of PGPB niche occupation and persistence according to the holobiont conditions. The effects of Ab-V5 and NS microbial communities were evaluated in microcosms by a combined approach of microbiomics (species-specific qPCR, 16S rRNA metataxonomics and metagenomics) and plant phenomics (conventional and high-throughput methods). Our results revealed a weak maize growth promoting effect of Ab-V5 inoculation in undiluted NS, contrasting the positive effects of NS dilutions 10-3, 10-6, 10-9 and IS with Ab-V5. Alpha diversity in NS + Ab-V5 soil samples was higher than in all other treatments in a time course of 25 days after sowing (DAS). At 15 DAS, alpha diversity indexes were different between NS and IS, but similar in all NS dilutions in rhizospheric samples. These differences were not persistent at 25 DAS, demonstrating a stabilization process in the rhizobiomes. In NS 10-3 +Ab-V5 and NS 10-6 Ab-V5, Ab-V5 persisted in the maize rhizosphere until 15 DAS in higher abundances compared to NS. In NS + Ab-V5, abundance of six taxa were positively correlated with response to (a)biotic stresses in plant-soil interface. Genes involved in bacterial metabolism of riboses and amino acids, and cresol degradation were abundant on NS 10-3 + Ab-V5, indicating that these pathways can contribute to plant growth promotion and might be a result of Ab-V5 performance as a microbial recruiter of beneficial functions to the plant. Our results demonstrated the effects of holobiont on Ab-V5 performance. The meta-omics integration supported by plant phenomics opens new perspectives to better understanding of inoculants-holobiont interaction and for developing better strategies for optimization in the use of microbial products.

E-learning as a strategy in dentistry in the context of COVID-19: a path to follow?

The current study aims to assess the effectiveness of e-learning in compliance with the new biosafety recommendations in dentistry in the context of COVID-19 applied to the clinical staff of a dental school in Brazil. A quasi-experimental epidemiological study was carried out by means of a structured, pre-tested online questionnaire, applied before and after an educational intervention, using an e-learning format. After data collection, statistical tests were performed. A total of 549 members of the clinical staff participated in the study in the two collection phases, with a return rate of 26.9%. After the e-learning stage, a reduction was found in the reported use of disposable gloves, protective goggles, and surgical masks. The course had no impact on the staff's knowledge concerning the proper sequence for donning PPE and showed 100% effectiveness regarding proper PPE doffing sequence. Knowledge about avoiding procedures that generate aerosols in the clinical setting was improved. Despite the low rate of return, it can be concluded that online intervention alone was ineffective in significantly improving learning about the new clinical biosafety guidelines. Therefore, the use of hybrid teaching and repetitive training is highly recommended.

Management of oral leukoplakia with an 808-nm high-power diode laser: a single-center experience.

PURPOSE: High-power diode laser emerges as a promising approach to the treatment of oral leukoplakia (OL); however, its short- and long-term effects have been barely explored. This study evaluated the postoperative endpoints and the recurrence rate of high-power diode laser treatment in a well-defined series of patients with OL. METHODS: A prospective analysis was performed on 22 individuals comprising 31 OL. The lesions were irradiated using the following protocol: Indium-Gallium-Arsenide diode laser, 808 nm, continuous-wave mode, 1.5-2.0 W, 780.0 ± 225.1 J, and 477.1 ± 131.8 s. Postoperative pain was assessed with a visual analog scale at three endpoints. Clinical follow-up was performed on all patients and the Kaplan-Meier test was used to analyze the probability of recurrence. RESULTS: The series consisted mostly of women (72.7%) with a mean age of 62.8 years. A single laser session was performed in 77.4% of cases. The median score on the scale that assessed pain on the 1st, 14th and 42nd postoperative day was 4, 1, and 0, respectively. The mean follow-up period per lesion was 28.6 months (range: 2-53 months). A complete response was observed in 93.5% of OL cases, while 6.5% had recurrence. The probability of recurrence at 39 months was 6.7%. No patient experienced malignant transformation. CONCLUSION: High-power diode laser for the treatment of OL is safe and effective during the trans- and postoperative period. These findings represent an alternative approach to the management of OL, mainly because a low recurrence rate was observed.

Epidemiological study of paediatric traumatic brain injury in Brazil.

Background: Traumatic brain injury (TBI) has a high economic and social impact on the family dynamics, particularly among children. High-quality and comprehensive epidemiological studies about TBI in this population are limited worldwide, specifically in Latin America. Therefore, this study aimed to elucidate the epidemiology of TBI among children in Brazil and its effects on the public health system. Methods: This epidemiological (cohort) retrospective study collected data from the Brazilian healthcare database between 1992 and 2021. Results: The mean annual volume of hospital admission (HA) due to TBI in Brazil was 29,017. Moreover, the incidence of TBI in the paediatric population was 45.35 admissions per 100,000 inhabitants/year. Furthermore, approximately 941 paediatric hospital deaths per year were caused by TBI, with an in-hospital lethality rate of 3.21%. The average annual financial transfer for TBI was 12,376,628 USD, and the mean cost per admission was 417 USD. In addition, the mean length of hospital stay was 4.2 days. Notably, the length of stay in the hospital was longer among males, Afro-Brazilians patients and individuals aged 15-19 years. Conclusion: Paediatric TBI is an important public health issue worldwide with high social and economic costs. The incidence of paediatric TBI in Brazil is similar to that in developing countries. Moreover, male predominance (2.3:1) was observed in relation paediatric TBI. Notably, during the pandemic, the incidence of paediatric HA has decreased. To the best of our knowledge, this is the first epidemiological study that specifically evaluates paediatric TBI in Latin America.

The Omicron Lineages BA.1 and BA.2 (Betacoronavirus SARS-CoV-2) Have Repeatedly Entered Brazil through a Single Dispersal Hub.

Brazil currently ranks second in absolute deaths by COVID-19, even though most of its population has completed the vaccination protocol. With the introduction of Omicron in late 2021, the number of COVID-19 cases soared once again in the country. We investigated in this work how lineages BA.1 and BA.2 entered and spread in the country by sequencing 2173 new SARS-CoV-2 genomes collected between October 2021 and April 2022 and analyzing them in addition to more than 18,000 publicly available sequences with phylodynamic methods. We registered that Omicron was present in Brazil as early as 16 November 2021 and by January 2022 was already more than 99% of samples. More importantly, we detected that Omicron has been mostly imported through the state of São Paulo, which in turn dispersed the lineages to other states and regions of Brazil. This knowledge can be used to implement more efficient non-pharmaceutical interventions against the introduction of new SARS-CoV variants focused on surveillance of airports and ground transportation.

Subsistence hunting and the introduction of Neotropical echinococcosis into the domestic environment in the Brazilian Amazon / Caça de subsistência e a introdução da equinococose neotropical no ambiente doméstico na Amazónia brasileira

The present study recorded the consumption of paca and agouti meat and revealed the presence of hydatid cysts in the livers of these rodents in extractivist communities in Brazilian Amazonia. A total of 42 families (with a median four of members per household) were interviewed, of which 98% (n=41) reported the consumption of paca and 86% (n=36) the consumption of agouti. Structures consistent with hydatid cysts were detected more frequently in the liver tissue of the pacas (74% ­ 31 of 42 samples) than the agoutis (26% ­ 11/42). The parasitological analysis of a paca liver confirmed the presence of E. vogeli. The consumption of the meat of these rodents and the confirmation of infection by E. vogeli represent preoccupying risk factors for the inhabitants of these forest communities, given that the uncooked viscera of both rodents are often fed to domestic dogs.

O presente estudo registrou o consumo de carne de paca e cutia e revelou a presença de cistos hidáticos nos fígados desses roedores em comunidades extrativistas da Amazônia brasileira. Foram entrevistadas 42 famílias (mediana quatro membros/família), destas 98% (n=41) informaram o consumo de paca e 86% (n=36) o consumo de cutia. Estruturas compatíveis com cistos hidáticos foram relatadas com maior frequência em fígados de pacas 74% (31/42) do que em cutias 26% (11/42). A análise parasitológica de um fígado de paca confirmou a presença de E. vogeli. O consumo da carne desses roedores e a confirmação da infecção por E. vogeli representam fatores de risco preocupantes para os moradores dessas comunidades florestais, uma vez que as vísceras cruas de ambos os roedores são utilizadas na alimentação de cães domésticos.

Shifts in functional traits and interactions patterns of soil methane-cycling communities following forest-to-pasture conversion in the Amazon Basin.

Deforestation threatens the integrity of the Amazon biome and the ecosystem services it provides, including greenhouse gas mitigation. Forest-to-pasture conversion has been shown to alter the flux of methane gas (CH4 ) in Amazonian soils, driving a switch from acting as a sink to a source of atmospheric CH4 . This study aimed to better understand this phenomenon by investigating soil microbial metagenomes, focusing on the taxonomic and functional structure of methane-cycling communities. Metagenomic data from forest and pasture soils were combined with measurements of in situ CH4 fluxes and soil edaphic factors and analysed using multivariate statistical approaches. We found a significantly higher abundance and diversity of methanogens in pasture soils. As inferred by co-occurrence networks, these microorganisms seem to be less interconnected within the soil microbiota in pasture soils. Metabolic traits were also different between land uses, with increased hydrogenotrophic and methylotrophic pathways of methanogenesis in pasture soils. Land-use change also induced shifts in taxonomic and functional traits of methanotrophs, with bacteria harbouring genes encoding the soluble form of methane monooxygenase enzyme (sMMO) depleted in pasture soils. Redundancy analysis and multimodel inference revealed that the shift in methane-cycling communities was associated with high pH, organic matter, soil porosity and micronutrients in pasture soils. These results comprehensively characterize the effect of forest-to-pasture conversion on the microbial communities driving the methane-cycling microorganisms in the Amazon rainforest, which will contribute to the efforts to preserve this important biome.

Functionality of methane cycling microbiome during methane flux hot moments from riparian buffer systems.

Riparian buffer systems (RBS) are a common agroforestry practice that involves maintaining a forested boundary adjacent to water bodies to protect the aquatic ecosystems in agricultural landscapes. While RBS have potential for carbon sequestration, they also can be sources of methane emissions. Our study site at Washington Creek in Southern Ontario, includes a rehabilitated tree buffer (RH), a grassed buffer (GRB), an undisturbed deciduous forest (UNF), an undisturbed coniferous forest (CF), and an adjacent agricultural field (AGR). The objective of this study was to assess the diversity and activity of CH4 cycling microbial communities in soils sampled during hot moments of methane fluxes (July 04 and August 15). We used qPCR and high-throughput amplicon sequencing from both DNA and cDNA to target methanogen and methanotroph communities. Methanogens, including the archaeal genera Methanosaeta, Methanosarcina, Methanomassiliicoccus, and Methanoreggula, were abundant in all RBSs, but they were significantly more active in UNF soils, where CH4 emissions were highest. Methylocystis was the most prevalent taxon among methanotrophs in all the riparian sites, except for AGR soils where the methanotrophs community was composed primarily of members of rice paddy clusters (RPCs and RPC-1) and upland soil clusters (TUSC and USCα). The main factors influencing the composition and assembly of methane-cycling microbiomes were soil carbon and moisture content. We concluded that the differences in CH4 fluxes observed between RBSs were primarily caused by differences in the presence and activity of methanogens, which were influenced by total soil carbon and water content. Overall, this study emphasizes the importance of understanding the microbial drivers of CH4 fluxes in RBSs in order to maximize RBS environmental benefits.