Identification of unique cell type responses in pancreatic islets to stress.

Diabetes involves the death or dysfunction of pancreatic ß-cells. Analysis of bulk sequencing from human samples and studies using in vitro and in vivo models suggest that endoplasmic reticulum and inflammatory signaling play an important role in diabetes progression. To better characterize cell type-specific stress response, we perform multiplexed single-cell RNA sequencing to define the transcriptional signature of primary human islet cells exposed to endoplasmic reticulum and inflammatory stress. Through comprehensive pair-wise analysis of stress responses across pancreatic endocrine and exocrine cell types, we define changes in gene expression for each cell type under different diabetes-associated stressors. We find that ß-, α-, and ductal cells have the greatest transcriptional response. We utilize stem cell-derived islets to study islet health through the candidate gene CIB1, which was upregulated under stress in primary human islets. Our findings provide insights into cell type-specific responses to diabetes-associated stress and establish a resource to identify targets for diabetes therapeutics.

Antibiotic treatment induces microbiome dysbiosis and reduction of neuroinflammation following traumatic brain injury in mice.

Background: The gut microbiome is linked to brain pathology in cases of traumatic brain injury (TBI), yet the specific bacteria that are implicated are not well characterized. To address this gap, in this study, we induced traumatic brain injury (TBI) in male C57BL/6J mice using the controlled cortical impact (CCI) injury model. After 35 days, we administered a broad-spectrum antibiotics (ABX) cocktail (ampicillin, gentamicin, metronidazole, vancomycin) through oral gavage for 2 days to diminish existing microbiota. Subsequently, we inflicted a second TBI on the mice and analyzed the neuropathological outcomes five days later. Results: Longitudinal analysis of the microbiome showed significant shifts in the diversity and abundance of bacterial genera during both acute and chronic inflammation. These changes were particularly dramatic following treatment with ABX and after the second TBI. ABX treatment did not affect the production of short-chain fatty acids (SCFA) but did alter intestinal morphology, characterized by reduced villus width and a lower count of goblet cells, suggesting potential negative impacts on intestinal integrity. Nevertheless, diminishing the intestinal microbiome reduced cortical damage, apoptotic cell density, and microglial/macrophage activation in the cortical and thalamic regions of the brain. Conclusions: Our findings suggest that eliminating colonized gut bacteria via broad-spectrum ABX reduces neuroinflammation and enhances neurological outcomes in TBI despite implications to gut health.

Seasonal dynamics of sand flies in Lençóis Maranhenses National Park: a tourist destination and endemic area for leishmaniasis.

Numerous sand fly species have been reported in Lençóis Maranhenses National Park (LMNP) in Northeast Brazil, including important Leishmania vectors, making the park an endemic area for tegumentary and visceral leishmaniasis. We evaluated sand fly abundance monthly over 7 years, correlating it with environmental variables and monthly tourist numbers in LMNP. Sand fly species were observed throughout the year, with Lutzomyia longipalpis Lutz & Neiva and Nyssomyia whitmani Antunes and Coutinho (Diptera: Psychodidae) being the most abundant species, especially from April to June. In addition to seasonal abundance patterns, Lu. longipalpis showed increasing abundance throughout 2013 until April 2014, whereas Ny. whitmani exhibited a consistent increase throughout the study period. Redundancy analysis indicated that monthly sand fly abundances increased with humidity but decreased with mean temperature and wind speed. Ecotourists mainly visit the park from May to September when interdune lagoons are full, coinciding with high-frequency vector activity during the rainy months (May-June). Tourists also visit in January and February during school holidays, when the rains begin and sand fly abundance increases, and in July, when sand fly abundance decreases. To date, no instances of infected tourists have been recorded, likely because visits to LMNP occur during the day when sand flies are inactive. However, there is a potential risk of vector exposure if tourists engage in nighttime cultural visits to villages around the park, where leishmaniasis cases occur annually.

Immunological Response against Breast Lineage Cells Transfected with Human Papillomavirus (HPV).

Breast cancer is the most common neoplasm worldwide. Viral infections are involved with carcinogenesis, especially those caused by oncogenic Human Papillomavirus (HPV) genotypes. Despite the detection of HPV in breast carcinomas, the virus's activity against this type of cancer remains controversial. HPV infection promotes remodeling of the host's immune response, resulting in an immunosuppressive profile. This study assessed the individual role of HPV oncogenes in the cell line MDA-MB-231 transfected with the E5, E6, and E7 oncogenes and co-cultured with peripheral blood mononuclear cells. Immunophenotyping was conducted to evaluate immune system modulation. There was an increase in CD4+ T cell numbers when compared with non-transfected and transfected MDA-MB-231, especially in the Treg profile. Pro-inflammatory intracellular cytokines, such as IFN-γ, TNF-α, and IL-17, were impaired by transfected cells, and a decrease in the cytolytic activity of the CD8+ and CD56+ lymphocytes was observed in the presence of HPV oncogenes, mainly with E6 and E7. The E6 and E7 oncogenes decrease monocyte expression, activating the expected M1 profile. In the monocytes found, a pro-inflammatory role was observed according to the cytokines released in the supernatant. In conclusion, the MDA-MB-231 cell lineage transfected with HPV oncogenes can downregulate the number and function of lymphocytes and monocytes.

Cryptic circulation of chikungunya virus in São Jose do Rio Preto, Brazil, 2015-2019.

BACKGROUND: Chikungunya virus (CHIKV) has spread across Brazil with varying incidence rates depending on the affected areas. Due to cocirculation of arboviruses and overlapping disease symptoms, CHIKV infection may be underdiagnosed. To understand the lack of CHIKV epidemics in São José do Rio Preto (SJdRP), São Paulo (SP), Brazil, we evaluated viral circulation by investigating anti-CHIKV IgG seroconversion in a prospective study of asymptomatic individuals and detecting anti-CHIKV IgM in individuals suspected of dengue infection, as well as CHIKV presence in Aedes mosquitoes. The opportunity to assess two different groups (symptomatic and asymptomatic) exposed at the same geographic region aimed to broaden the possibility of identifying the viral circulation, which had been previously considered absent. METHODOLOGY/PRINCIPAL FINDINGS: Based on a prospective population study model and demographic characteristics (sex and age), we analyzed the anti-CHIKV IgG seroconversion rate in 341 subjects by ELISA over four years. The seroprevalence increased from 0.35% in the first year to 2.3% after 3 years of follow-up. Additionally, we investigated 497 samples from a blood panel collected from dengue-suspected individuals during the 2019 dengue outbreak in SJdRP. In total, 4.4% were positive for anti-CHIKV IgM, and 8.6% were positive for IgG. To exclude alphavirus cross-reactivity, we evaluated the presence of anti-Mayaro virus (MAYV) IgG by ELISA, and the positivity rate was 0.3% in the population study and 0.8% in the blood panel samples. In CHIKV and MAYV plaque reduction neutralization tests (PRNTs), the positivity rate for CHIKV-neutralizing antibodies in these ELISA-positive samples was 46.7%, while no MAYV-neutralizing antibodies were detected. Genomic sequencing and phylogenetic analysis revealed CHIKV genotype ECSA in São José do Rio Preto, SP. Finally, mosquitoes collected to complement human surveillance revealed CHIKV positivity of 2.76% of A. aegypti and 9.09% of A. albopictus (although it was far less abundant than A. aegypti) by RT-qPCR. CONCLUSIONS/SIGNIFICANCE: Our data suggest cryptic CHIKV circulation in SJdRP detected by continual active surveillance. These low levels, but increasing, of viral circulation highlight the possibility of CHIKV outbreaks, as there is a large naïve population. Improved knowledge of the epidemiological situation might aid in outbreaks prevention.

Diagnostic disclosure of Alzheimer's disease in Brazil: a national survey of specialized physicians.

BACKGROUND: The diagnosis of Alzheimer's disease (AD) can bring financial and emotional consequences to patients and caregivers. Whether or not the diagnosis should be disclosed to patients is a matter of debate amongst physicians and can be influenced by culture and experience. OBJECTIVE: To investigate the current practice of physicians who attend and treat patients with dementia in Brazil regarding the disclosure of dementia diagnosis and compare the practice with what has been performed 15 years ago in the country. METHODS: Data were evaluated using an electronic questionnaire. The questions used to carry out this research were similar to the questions of the study carried out 15 years ago 9. The form was sent to the Brazilian Academy of Neurology, the Brazilian Association of Geriatrics and Gerontology, and the Brazilian Association of Psychiatry, which forwarded it to their members. Analyses were conducted through non-parametric statistical tests, with a post-hoc assessment. RESULTS: 397 physicians responded to the survey, of which 231 are neurologists, 124 geriatricians, 29 psychiatrists and 13 from other specialties. The mean age was 45.2 years. The majority (66.7%) of the physicians reveal the diagnosis of AD always or usually. The youngest group of neurologists were more likely to disclose the diagnosis than the oldest group with a significant difference between them. In comparison to the 2008 Brazilian study, the percentage of physicians who always or usually disclose the diagnosis has risen by 22%. On the other hand, 12.3% of the physicians rarely or never disclose the diagnosis, in comparison to 25,3% in 2008. The main reasons for not disclosing the diagnosis concern the patients' mental health. CONCLUSION: Advances in dementia knowledge and biomarkers availability probably explain the increase in the rate of disclosure. The main challenge is to reconcile the autonomy of affected individuals, mental health issues after the diagnosis and the family member's opinion.

ANTECEDENTES: O diagnóstico da doença de Alzheimer (DA) pode trazer consequências financeiras e emocionais para pacientes e cuidadores. Revelar ou não o diagnóstico aos pacientes é uma questão de debate entre os médicos e pode ser influenciada pela cultura e experiência. OBJETIVO: Investigar a prática atual dos médicos que atendem e tratam pacientes com demência no Brasil quanto à revelação do diagnóstico de demência e comparar a prática com a qual era feita há 15 anos no país. MéTODOS:: Os dados foram avaliados por meio de um questionário eletrônico. As perguntas usadas para realização dessa pesquisa foram similares às perguntas do estudo realizado há 15 anos 9. O formulário foi enviado à Academia Brasileira de Neurologia, à Associação Brasileira de Geriatria e Gerontologia, e à Associação Brasileira de Psiquiatria, as quais o encaminharam aos seus membros. As análises foram realizadas por meio de testes estatísticos não paramétricos, com avaliação post-hoc. RESULTADOS: 397 médicos responderam à pesquisa, sendo 231 neurologistas, 124 geriatras, 29 psiquiatras e 13 de outras especialidades. A média de idade foi de 45,2 anos (standard deviation-SD = 11.6 years). A maioria (66,7%) dos médicos revela o diagnóstico de DA sempre ou habitualmente. O grupo mais jovem de neurologistas foi mais propenso a revelar o diagnóstico do que o mais velho, com diferença significativa entre eles. Em comparação com o estudo brasileiro de 2008, o percentual de médicos que sempre ou usualmente revelam o diagnóstico aumentou em 22%. Em contrapartida, 12,3% dos médicos raramente ou nunca o divulgam, em comparação a 25,3% em 2008. Os principais motivos para não o revelar dizem respeito à saúde mental dos pacientes. CONCLUSãO:: Avanços no conhecimento da demência e disponibilidade de biomarcadores provavelmente explicam o aumento na taxa de divulgação. O principal desafio é conciliar a autonomia dos indivíduos afetados, problemas de saúde mental após o diagnóstico e opinião do familiar.

Minimally invasive surgery as a new clinical standard for bone anchored hearing implants-real-world data from 10 years of follow-up and 228 surgeries.

Purpose: To explore the clinical practice development of different surgical techniques when installing bone-anchored hearing implants and their associated trends in outcomes. Design: Retrospective study of 228 bone-anchored hearing implants in 200 patients, performed over a 10-year period between 2012 and 2022 in a referral hospital. Method: Real-world data of demography, etiology, surgical setup, complications, and audiological outcomes were collected. Eligibility criteria from clinical practice were applied. Results: The minimally invasive technique is associated with shorter surgery duration, 20 vs. 44 min as compared to a linear incision technique. The minimally invasive technique was also associated with a lower occurrence of complications when compared to linear incision techniques (intraoperative; 1.8% vs. 4.9%, postoperative; 49% vs. 66%). Most differences were seen in complications relating to skin and wound healing. Conclusion: Adoption of a minimally invasive surgical technique for the installations of bone-anchored hearing implants can reduce surgical complexity without compromising safety aspects or clinical benefits.

Single-nucleus multi-omics of human stem cell-derived islets identifies deficiencies in lineage specification.

Insulin-producing ß cells created from human pluripotent stem cells have potential as a therapy for insulin-dependent diabetes, but human pluripotent stem cell-derived islets (SC-islets) still differ from their in vivo counterparts. To better understand the state of cell types within SC-islets and identify lineage specification deficiencies, we used single-nucleus multi-omic sequencing to analyse chromatin accessibility and transcriptional profiles of SC-islets and primary human islets. Here we provide an analysis that enabled the derivation of gene lists and activity for identifying each SC-islet cell type compared with primary islets. Within SC-islets, we found that the difference between ß cells and awry enterochromaffin-like cells is a gradient of cell states rather than a stark difference in identity. Furthermore, transplantation of SC-islets in vivo improved cellular identities overtime, while long-term in vitro culture did not. Collectively, our results highlight the importance of chromatin and transcriptional landscapes during islet cell specification and maturation.

Effects of ß -caryophyllene, A Dietary Cannabinoid, in Animal Models of Drug Addiction.

BACKGROUND: ß-caryophyllene (BCP) is a natural bicyclic sesquiterpene found in Cannabis and other plants. BCP is currently used as a food additive, although pharmacological studies suggest its potential therapeutic application for the treatment of certain brain disorders. The mechanisms of action of BCP remain uncertain, possibly including full agonism at the cannabinoid CB2 receptor (CB2R). OBJECTIVE: The study aims to investigate BCP's potential as a new drug for the treatment of substance use disorders by reviewing preclinical studies with animal models. RESULTS: BCP has been investigated in behavioral paradigms, including drug self-administration, conditioned place preference, and intracranial self-stimulation; the drugs tested were cocaine, nicotine, alcohol, and methamphetamine. Remarkably, BCP prevented or reversed behavioral changes resulting from drug exposure. As expected, the mechanism of action entails CB2R activation, although this is unlikely to constitute the only molecular target to explain such effects. Another potential target is the peroxisome proliferator-activated receptor. CONCLUSION: Preclinical studies have reported promising results with BCP in animal models of substance use disorders. Further research, including studies in humans, are warranted to establish its therapeutic potential and its mechanisms of action.

Diagnostic disclosure of Alzheimer's disease in Brazil: a national survey of specialized physicians / Revelação do diagnóstico da doença de Alzheimer no Brasil: prática corrente de médicos que atendem pacientes com demência

Abstract Background: The diagnosis of Alzheimer's disease (AD) can bring financial and emotional consequences to patients and caregivers. Whether or not the diagnosis should be disclosed to patients is a matter of debate amongst physicians and can be influenced by culture and experience. Objective: To investigate the current practice of physicians who attend and treat patients with dementia in Brazil regarding the disclosure of dementia diagnosis and compare the practice with what has been performed 15 years ago in the country. Methods: Data were evaluated using an electronic questionnaire. The questions used to carry out this research were similar to the questions of the study carried out 15 years ago 9. The form was sent to the Brazilian Academy of Neurology, the Brazilian Association of Geriatrics and Gerontology, and the Brazilian Association of Psychiatry, which forwarded it to their members. Analyses were conducted through non-parametric statistical tests, with a post-hoc assessment. Results: 397 physicians responded to the survey, of which 231 are neurologists, 124 geriatricians, 29 psychiatrists and 13 from other specialties. The mean age was 45.2 years. The majority (66.7%) of the physicians reveal the diagnosis of AD always or usually. The youngest group of neurologists were more likely to disclose the diagnosis than the oldest group with a significant difference between them. In comparison to the 2008 Brazilian study, the percentage of physicians who always or usually disclose the diagnosis has risen by 22%. On the other hand, 12.3% of the physicians rarely or never disclose the diagnosis, in comparison to 25,3% in 2008. The main reasons for not disclosing the diagnosis concern the patients' mental health. Conclusion: Advances in dementia knowledge and biomarkers availability probably explain the increase in the rate of disclosure. The main challenge is to reconcile the autonomy of affected individuals, mental health issues after the diagnosis and the family member's opinion.

Resumo Antecedentes: O diagnóstico da doença de Alzheimer (DA) pode trazer consequências financeiras e emocionais para pacientes e cuidadores. Revelar ou não o diagnóstico aos pacientes é uma questão de debate entre os médicos e pode ser influenciada pela cultura e experiência. Objetivo: Investigar a prática atual dos médicos que atendem e tratam pacientes com demência no Brasil quanto à revelação do diagnóstico de demência e comparar a prática com a qual era feita há 15 anos no país. Métodos: Os dados foram avaliados por meio de um questionário eletrônico. As perguntas usadas para realização dessa pesquisa foram similares às perguntas do estudo realizado há 15 anos 9. O formulário foi enviado à Academia Brasileira de Neurologia, à Associação Brasileira de Geriatria e Gerontologia, e à Associação Brasileira de Psiquiatria, as quais o encaminharam aos seus membros. As análises foram realizadas por meio de testes estatísticos não paramétricos, com avaliação post-hoc. Resultados: 397 médicos responderam à pesquisa, sendo 231 neurologistas, 124 geriatras, 29 psiquiatras e 13 de outras especialidades. A média de idade foi de 45,2 anos (standard deviation-SD = 11.6 years). A maioria (66,7%) dos médicos revela o diagnóstico de DA sempre ou habitualmente. O grupo mais jovem de neurologistas foi mais propenso a revelar o diagnóstico do que o mais velho, com diferença significativa entre eles. Em comparação com o estudo brasileiro de 2008, o percentual de médicos que sempre ou usualmente revelam o diagnóstico aumentou em 22%. Em contrapartida, 12,3% dos médicos raramente ou nunca o divulgam, em comparação a 25,3% em 2008. Os principais motivos para não o revelar dizem respeito à saúde mental dos pacientes. Conclusão: Avanços no conhecimento da demência e disponibilidade de biomarcadores provavelmente explicam o aumento na taxa de divulgação. O principal desafio é conciliar a autonomia dos indivíduos afetados, problemas de saúde mental após o diagnóstico e opinião do familiar.

Genetic architecture and temporal analysis of Caenorhabditis briggsae hybrid developmental delay.

Identifying the alleles that reduce hybrid fitness is a major goal in the study of speciation genetics. It is rare to identify systems in which hybrid incompatibilities with minor phenotypic effects are segregating in genetically diverse populations of the same biological species. Such traits do not themselves cause reproductive isolation but might initiate the process. In the nematode Caenorhabditis briggsae, a small percent of F2 generation hybrids between two natural populations suffer from developmental delay, in which adulthood is reached after approximately 33% more time than their wild-type siblings. Prior efforts to identify the genetic basis for this hybrid incompatibility assessed linkage using one or two genetic markers on chromosome III and suggested that delay is caused by a toxin-antidote element. Here, we have genotyped F2 hybrids using multiple chromosome III markers to refine the developmental delay locus. Also, to better define the developmental delay phenotype, we measured the development rate of 66 F2 hybrids and found that delay is not restricted to a particular larval developmental stage. Deviation of the developmental delay frequency from hypothetical expectations for a toxin-antidote element adds support to the assertion that the epistatic interaction is not fully penetrant. Our mapping and refinement of the delay phenotype motivates future efforts to study the genetic architecture of hybrid dysfunction between genetically distinct populations of one species by identifying the underlying loci.

Memory elicitation, T-cell response and antibody production: an independent study of an inactivated entire virus vaccine (Coronavac).

Health professionals working to mitigate the COVID-19 pandemic are one of the main risk groups for the disease, being prioritized for vaccination. Considering this, the aim of this study was to analyze the immune response of these professionals immunized with CoronaVac in the first and second doses. Blood samples were collected after the first and second doses of the vaccine (CoronaVac) and used to investigate hematological and biochemical parameters, analysis of immunoglobulin production, cytokines, and gene expression profile, as well as the identification of subsets of immune cells. Post-first dose immunological phenotypic memory (CD27+) profiles (T CD4+, TCD8+ and CD19+) showed a significant increase, as did Monocyte APCs (CD80+HLA-DR+) in relation to the second dose. The cytokines IL-2, IL-6 and IFN-° showed increased values in relation to the other analyzed cytokines. The Th2/Th17 profile in the second dose was characterized by gene expression analysis. The production of IgM and IgG after vaccination showed statistically significant values in the comparison between doses. CoronaVac showed activation of APCs monocytes, memory response of T and B lymphocytes, with immunoglobulins production. This set of responses is characterized by the Th2/Th17 immunological profile.

The microbiome of a shell mound: ancient anthropogenic waste as a source of Streptomyces degrading recalcitrant polysaccharides.

Metagenome amplicon DNA sequencing and traditional cell culture techniques are helping to uncover the diversity and the biotechnological potential of prokaryotes in different habitats around the world. It has also had a profound impact on microbial taxonomy in the last decades. Here we used metagenome 16S rDNA amplicon sequencing to reveal the microbiome composition of different layers of an anthropogenic soil collected at a shell mound Sambaqui archeological site. The Samabaqui soil microbiome is mainly composed by phyla Acidobacteria, Rokubacteria, Proteobacteria and Thaumarchaeota. Using culture-dependent analysis we obtained few Streptomyces isolates from the Sambaqui soil. One of the isolates, named Streptomyces sp. S3, was able to grow in minimal medium containing recalcitrant polysaccharides including chitin, xylan, carboxymethylcellulose or microcrystalline cellulose as sole carbon sources. The activities of enzymes degrading these compounds were confirmed in cell free supernatants. The genome sequence revealed not only an arsenal of genes related to polysaccharides degradation but also biosynthetic gene clusters which may be involved in the production of biotechnologically interesting secondary metabolites.

In silico comparative analysis of Aeromonas Type VI Secretion System.

Aeromonas are bacteria broadly spread in the environment, particularly in aquatic habitats and can induce human infections. Several virulence factors have been described associated with bacterial pathogenicity, such as the Type VI Secretion System (T6SS). This system translocates effector proteins into target cells through a bacteriophage-like contractile structure encoded by tss genes. Here, a total of 446 Aeromonas genome sequences were screened for T6SS and the proteins subjected to in silico analysis. The T6SS-encoding locus was detected in 243 genomes and its genes are encoded in a cluster containing 13 core and 5 accessory genes, in highly conserved synteny. The amino acid residues identity of T6SS proteins ranges from 78 to 98.8%. In most strains, a pair of tssD and tssI is located upstream the cluster (tssD-2, tssI-2) and another pair was detected distant from the cluster (tssD-1, tssI-1). Significant variability was seen in TssI (VgrG) C-terminal region, which was sorted in four groups based on its sequence length and protein domains. TssI containing ADP-ribosyltransferase domain are associated exclusively with TssI-1, while genes coding proteins carrying DUF4123 (a conserved domain of unknown function) were observed downstream tssI-1 or tssI-2 and escort of possible effector proteins. Genes coding proteins containing DUF1910 and DUF1911 domains were located only downstream tssI-2 and might represent a pair of toxin/immunity proteins. Nearly all strains display downstream tssI-3, that codes for a lysozyme family domain protein. These data reveal that Aeromonas T6SS cluster synteny is conserved and the low identity observed for some genes might be due to species heterogeneity or its niche/functionality.

Comparative Genomics Provides Insights into the Taxonomy of Azoarcus and Reveals Separate Origins of Nif Genes in the Proposed Azoarcus and Aromatoleum Genera.

Among other attributes, the Betaproteobacterial genus Azoarcus has biotechnological importance for plant growth-promotion and remediation of petroleum waste-polluted water and soils. It comprises at least two phylogenetically distinct groups. The "plant-associated" group includes strains that are isolated from the rhizosphere or root interior of the C4 plant Kallar Grass, but also strains from soil and/or water; all are considered to be obligate aerobes and all are diazotrophic. The other group (now partly incorporated into the new genus Aromatoleum) comprises a diverse range of species and strains that live in water or soil that is contaminated with petroleum and/or aromatic compounds; all are facultative or obligate anaerobes. Some are diazotrophs. A comparative genome analysis of 32 genomes from 30 Azoarcus-Aromatoleum strains was performed in order to delineate generic boundaries more precisely than the single gene, 16S rRNA, that has been commonly used in bacterial taxonomy. The origin of diazotrophy in Azoarcus-Aromatoleum was also investigated by comparing full-length sequences of nif genes, and by physiological measurements of nitrogenase activity using the acetylene reduction assay. Based on average nucleotide identity (ANI) and whole genome analyses, three major groups could be discerned: (i) Azoarcus comprising Az. communis, Az. indigens and Az. olearius, and two unnamed species complexes, (ii) Aromatoleum Group 1 comprising Ar. anaerobium, Ar. aromaticum, Ar. bremense, and Ar. buckelii, and (iii) Aromatoleum Group 2 comprising Ar. diolicum, Ar. evansii, Ar. petrolei, Ar. toluclasticum, Ar. tolulyticum, Ar. toluolicum, and Ar. toluvorans. Single strain lineages such as Azoarcus sp. KH32C, Az. pumilus, and Az. taiwanensis were also revealed. Full length sequences of nif-cluster genes revealed two groups of diazotrophs in Azoarcus-Aromatoleum with nif being derived from Dechloromonas in Azoarcus sensu stricto (and two Thauera strains) and from Azospira in Aromatoleum Group 2. Diazotrophy was confirmed in several strains, and for the first time in Az. communis LMG5514, Azoarcus sp. TTM-91 and Ar. toluolicum TT. In terms of ecology, with the exception of a few plant-associated strains in Azoarcus (s.s.), across the group, most strains/species are found in soil and water (often contaminated with petroleum or related aromatic compounds), sewage sludge, and seawater. The possession of nar, nap, nir, nor, and nos genes by most Azoarcus-Aromatoleum strains suggests that they have the potential to derive energy through anaerobic nitrate respiration, so this ability cannot be usefully used as a phenotypic marker to distinguish genera. However, the possession of bzd genes indicating the ability to degrade benzoate anaerobically plus the type of diazotrophy (aerobic vs. anaerobic) could, after confirmation of their functionality, be considered as distinguishing phenotypes in any new generic delineations. The taxonomy of the Azoarcus-Aromatoleum group should be revisited; retaining the generic name Azoarcus for its entirety, or creating additional genera are both possible outcomes.

Influence of seasonality on the aerosol microbiome of the Amazon rainforest.

The Amazon rainforest is the world's largest tropical forest, and this biome may be a significant contributor to primary biological aerosol (PBA) emissions on a global scale. These aerosols also play a pivotal role in modulating ecosystem dynamics, dispersing biological material over geographic barriers and influencing climate through radiation absorption, light scattering, or acting as cloud condensation nuclei. Despite their importance, there are limited studies investigating the effect of environmental variables on the bioaerosol composition in the Amazon rainforest. Here we present a 16S rRNA gene-based amplicon sequencing approach to investigate the bacterial microbiome in aerosols of the Amazon rainforest during distinct seasons and at different heights above the ground. Our data revealed that seasonal changes in temperature, relative humidity, and precipitation are the primary drivers of compositional changes in the Amazon rainforest aerosol microbiome. Interestingly, no significant differences were observed in the bacterial community composition of aerosols collected at ground and canopy levels. The core airborne bacterial families present in Amazon aerosol were Enterobacteriaceae, Beijerinckiaceae, Polyangiaceae, Bacillaceae and Ktedonobacteraceae. By correlating the bacterial taxa identified in the aerosol with literature data, we speculate that the phyllosphere may be one possible source of airborne bacteria in the Amazon rainforest. Results of this study indicate that the aerosol microbiota of the Amazon Rainforest are fairly diverse and principally impacted by seasonal changes in temperature and humidity.

Transmission networks and ectoparasite mite burdens in Oecomys paricola (Rodentia: Cricetidae).

The host contact network structure results from the movement and behaviour of hosts (e.g. degree of sociability; vagility and greater or lesser fidelity of shelters), which can generate heterogeneity in the transmission of parasites and influence the parasitic burden of individual hosts. In the current study, we tested the hypothesis that the burdens of Gigantolaelaps oudemansi mites are related to the characteristics of the transmission networks of individuals of Oecomys paricola, a solitary rodent. The study was carried out in a savannah habitat in north-eastern Brazil. In the dry season, the rodent network presented sub-groups of rodent individuals interacting with each other, whereas in the wet season, no modules were formed in the network. Mite burden was positively related to the number of connections that an individual host had with other host individuals in the dry season. The pairwise absolute difference between the mean mite burdens among individual rodents was negatively correlated with the similarities of node interactions. No relationships were observed during the wet season. There was a higher heterogeneity of mite burden among hosts in the dry season compare to that in the wet season. In solitary species, spatial organization may show seasonal variation, causing a change in the opportunities of host contacts, thereby influencing the transmission and dispersion of their ectoparasite burdens.

Microbial communities network analysis of anaerobic reactors fed with bovine and swine slurry.

Anaerobic digestion can produce biogas as an eco-friendly energy source, driven by a microbial community-dependent process and, as such, suffer influences from many biotic and abiotic factors. Understanding the players and how they interact, the mechanisms involved, what the factors are, and how they influence the biogas process and production is an important way to better control it and make it more efficient. Metagenomic approach is a powerful tool to assess microbial diversity and further, allow correlating changes in microbial communities with multiple factors in virtually all environments. In the present study, we used metagenomic approach to assess microbial community structure changes in two biodigesters, differing in their biogas production capacity, architecture, and feed. A total of 1,440,096 reads of the 16S rRNA gene V4 region were obtained and analyzed. The main bacterial phyla were Firmicutes and Bacteroidetes in both biodigesters, but the biodiversity was greater in the Upflow Anaerobic Sludge Blanket (UASB) reactor fed with bovine manure than in the Continuous Stirred Tank Reactor (CSTR) fed with swine manure, which also correlated with an increase in biogas or methane production. Microbial community structure associated with biodigesters changed seasonally and depended on animal growth stage. Random forest algorithm analysis revealed key microbial taxa for each biodigester. Candidatus Cloacomonas, Methanospirillum, and Methanosphaera were the marker taxa for UASB and the archaea groups Methanobrevibacter and Candidatus Methanoplasma were the marker taxa for CSTR. A high abundance of Candidatus Methanoplasma and Marinimicrobia SAR406 clade suggested lower increments in methane production. Network analysis pointed to negative and positive associations and specific key groups, essential in maintaining the anaerobic digestion (AD) process, as being uncultured Parcubacteria bacteria, Candidatus Cloacomonas, and Candidatus Methanoplasma groups, whose functions in AD require investigation.