How does landscape anthropization affect the myrmecofauna of urban forest fragments?

We evaluate whether landscape variables surrounding urban remnant forest fragments influence ant diversity and its components in urban areas. The study was conducted in six riparian forest fragments in midwestern Minas Gerais State, Brazil, by sampling epigaeic and arboreal ants. Arboreal ants respond to fragmente isolation with changes in alpha, beta and gamma diversities. Isolation likely hinders dispersion and re-colonization such that the more isolated a fragment is, the less likely that new species arrive there. On other hand, epigaeic diversity did not show any response to variables of the surroundings or fragments, probably because natural periodic floods constitute a more severe disturbance for these ants. In addition, throughout the process of urbanization, anthropogenic improvements, such as paving, that prevent the natural percolation of water, increase the flooding of riparian soil. Arboreal ant species composition responds to percentage of urban area, fragment area and distance from the urban center, while epigaeic ants respond only to fragment area and percentage of urban area. We believe that even with the loss of species diversity and anthropogenic influences on fragments within urban centers, these areas are still important for species conservation. We also suggest the development of environmental protection projects for riparian áreas within urban centers, including investments in ecological corridors connecting fragments and public policies seeking to preserve these areas

Ant species that remove diaspores alone are more efficient removers

Secondary diaspore removal on the ground is an important ecosystem process. In this process, solitary foraging ants with larger body sizes are more efficient because they may remove more diaspores, faster and carry them at greater distances. Therefore, we sought to test the effects of the sizes of the morphological traits of ants, removal strategy, and nest distance on secondary diaspore removal, testing hypotheses related to the efficiency of this process. We evaluated the removal of artificial diaspores by ants in 15 areas of Cerrado sensu stricto (tropical savanna), collecting data on diaspore removal strategy (solitary or group), nest distance, diaspore discovery time, diaspore removal time, and the number of diaspores removed. Larger ants tended to remove diaspores alone and remove diaspores faster than smaller ones. Ants that removed diaspores alone removed more diaspores than ants that removed diaspores in groups. However, we did not find a linear relationship between ant size and diaspore removal. This is likely due to a limitation on, or a preference by larger ants for removing larger diaspores, while the smaller diaspores may have hindered manipulation or been less attractive to larger ants. Thus, the removal strategy was the best predictor of efficient diaspore removal performance, where the solitary foraging ants discover and remove diaspores quickly and remove more diaspores, mainly from the closest nests to the sampling point. However, the benefits (or not) of removing more diaspores still need to be evaluated

Ants (Hymenoptera, Formicidae) of APA Pandeiros: A Perspective from a Decade of Research in an Environmental Protection Area in the Cerrado-Caatinga Transition

Habitat transformation and species loss bring enormous environmental damage, whereas establishing protected areas promotes more sustainable use of environmental resources through biodiversity conservation. In this study, we aimed to point out gaps in ant knowledge and provide a species checklist that contributes to biodiversity conservation in the transition areas between Cerrado and Caatinga biomes, constantly threatened by land use changes. This checklist integrates data from previous studies developed at “Área de Proteção Ambiental do Rio Pandeiros” (APA Pandeiros), Minas Gerais, Brazil, involving ant diversity and their contribution to ecological processes accessed and described in the studies. We showed and discussed how authors managed and provided information regarding methodologies and habitats sampled. We listed 143 ant species formally named. Pheidole, Camponotus and Cephalotes were the most speciose genera, with more than ten species each. Among ants involved in ecological processes, 40 are linked to diaspore removal (part of seed dispersal) and 30 to carcass interaction (part of the decomposition process). Unbaited pitfall traps, epigeic stratum and Cerrado sensu stricto, were the top sampling method, stratum, and habitats among ant studies. We presented proposals for the best management and integration of data from surveys in APA Pandeiros (e.g., sharing the results of the studies with the APA managers, creating a database, and the local community). These surveys are fundamental for understanding biodiversity and ecological processes and provide valuable information to conservation biology. Therefore, neglecting the importance of the Cerrado-Caatinga transition can lead to irreparable setbacks for scientific knowledge and biodiversity

Changes in Epigaeic Ant Assemblage Structure in the Amazon during Successional Processes after Bauxite Mining

Environmental impact studies often involve monitoring and using bioindicators to evaluate the restoration stage of impacted areas. We aimed to assess ant assemblages’ response to the ecological succession of previously disturbed areas in the Brazilian Amazon. We sampled epigeic ant assemblages in five bauxite mining areas, representing different restoration stages, and compared them with two pristine areas. We also compared trends in species richness at the same mine site investigated 14 years earlier. Ten pitfall traps and four Winkler samples of litter were taken along a 100-m transect in each area. We expected that ant species richness would increase with the amelioration in habitat condition (i.e., environmental surrogates of ecological succession, including litter depth, soil penetrability, the circumference of trees, the distance of trees to adjacent trees, and percentage of ground cover). We also compared the efficacy of both sampling methods. Due to more significant sampling effort, pitfall traps captured more ant species than Winkler sacks. However, Winkler samples’ addition allowed the collection of more cryptic species than by pitfall traps alone. We sampled a total of 129 ant species, with increases in ant species richness in more mature rehabilitation. Nevertheless, similarity analysis indicated a significant difference between ant assemblages of rehabilitated areas and pristine ones. Assemblages differed mainly by the presence of specialist and rare species, found only in pristine plots. Rehabilitated areas exhibited a significant increase in tree circumference as they reached more ecologically advanced stages, which contributed to increasing ant species richness. These trends and comparison with the earlier study indicate that although there are favorable increases in ant species richness, in terms of species composition, rehabilitated areas were far from achieving an ant assemblage composition or environmental status that closely resembles pristine areas

Geographical variation in ant foraging activity and resource use is driven by climate and net primary productivity

AIM : Foraging activity is critical for animal survival. Comprehending how ecological drivers influence foraging behaviour would benefit our understanding of the link between animals and ecological processes. Here, we evaluated the influence of ecological drivers on ant foraging activity and relative resource use. LOCATION : Six Brazilian biomes: Amazon, Atlantic rainforest, Caatinga, Cerrado, Pampa and Pantanal. TAXON : Formicidae. METHODS : We assessed ant foraging activity and resource use by sampling across 60 sites. We placed baited tubes that contained one of five liquid resources (sugar, lipids, amino acid, sodium and distilled water). We used model selection to assess the influence of ecological drivers (temperature, precipitation, temperature seasonality and net primary productivity) on ant foraging activity and relative resource use. RESULTS : Foraging activity was higher in wetter, more productive and less thermally seasonal environments. The relative use of amino acids increased at higher temperatures while the relative use of lipids decreased. The relative use of sugar increased in drier and less productive environments with high-temperature seasonality while the relative use of amino acid and sodium decreased in those environments. The relative use of lipids was complex: increasing with increasing temperature seasonality and decreasing with increasing precipitation. Furthermore, the relative use of sodium was greater where the foraging activity was high. MAIN CONCLUSIONS : We demonstrate how ecological drivers are correlated with ant foraging activity and resource use in the field across large spatial scales. The search for resources encompasses different interactions involving ants with abiotic and biotic components in the ecosystem. Thus, we suggest that changes in climate and NPP, which influence the intensity and the way that ants search for resources, will result in changes in ant-mediated ecological processes.Chaim J. Lasmar is a Post-doctoral researcher at the Programa de Pós-Graduação em Ecologia Aplicada (Universidade Federal de Lavras, Brazil). This study was part of his Ph. D. work at the Universidade Federal de Lavras with an internship period at the University of Liverpool.DATA AVAILABILITY STATEMENT: All data have been uploaded to Dryad (https://doi.org/10.5061/dryad.6wwpzgmxc).Fundação de Amparo à Pesquisa do Estado de Minas Gerais and Rufford Foundation.http://wileyonlinelibrary.com/journal/jbiam2022Zoology and Entomolog

Characterization of oral enterobacteriaceae prevalence and resistance profile in chronic kidney disease patients undergoing peritoneal dialysis

Chronic Kidney Disease (CKD) is a growing public-health concern worldwide. Patients exhibit compromised immunity and are more prone to infection than other populations. Therefore, oral colonization by clinically relevant members of the Enterobacteriaceae family, major agents of both nosocomial and dialysis-associated infections with frequent prevalence of antibiotic resistances, may constitute a serious risk. Thus, this study aimed to assess the occurrence of clinically relevant enterobacteria and their antibiotic resistance profiles in the oral cavity of CKD patients undergoing peritoneal dialysis (CKD-PD) and compare it to healthy controls. Saliva samples from all the participants were cultured on MacConkey Agar and evaluated regarding the levels of urea, ammonia, and pH. Bacterial isolates were identified and characterized for antibiotic resistance phenotype and genotype. The results showed that CKD-PD patients exhibited significantly higher salivary pH, urea, and ammonia levels than controls, that was accompanied by higher prevalence and diversity of oral enterobacteria. Out of all the species isolated, only the prevalence of Raoultella ornithinolytica varied significantly between groups, colonizing the oral cavity of approximately 30% of CKD-PD patients while absent from controls. Antibiotic resistance phenotyping revealed mostly putative intrinsic resistance phenotypes (to amoxicillin, ticarcillin, and cephalothin), and resistance to sulfamethoxazole (~43% of isolates) and streptomycin (~17%). However, all isolates were resistant to at least one of the antibiotics tested and multidrug resistance isolates were only found in CKD-PD group (31,6%). Mobile genetic elements and resistance genes were detected in isolates of the species Raoultella ornithinolytica, Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, and Enterobacter asburiae, mostly originated from CKD-PD patients. PD-related infection history revealed that Enterobacteriaceae were responsible for ~8% of peritonitis and ~ 16% of exit-site infections episodes in CKD-PD patients, although no association was found to oral enterobacteria colonization at the time of sampling. The results suggest that the CKD-induced alterations of the oral milieu might promote a dysbiosis of the commensal oral microbiome, namely the proliferation of clinically relevant Enterobacteriaceae potentially harboring acquired antibiotic resistance genes. This study highlights the importance of the oral cavity as a reservoir for pathobionts and antibiotic resistances in CKD patients undergoing peritoneal dialysis.info:eu-repo/semantics/publishedVersio

Genome-wide association analysis of dementia and its clinical endophenotypes reveal novel loci associated with Alzheimer's disease and three causality networks : The GR@ACE project

Introduction: Large variability among Alzheimer's disease (AD) cases might impact genetic discoveries and complicate dissection of underlying biological pathways. Methods: Genome Research at Fundacio ACE (GR@ACE) is a genome-wide study of dementia and its clinical endophenotypes, defined based on AD's clinical certainty and vascular burden. We assessed the impact of known AD loci across endophenotypes to generate loci categories. We incorporated gene coexpression data and conducted pathway analysis per category. Finally, to evaluate the effect of heterogeneity in genetic studies, GR@ACE series were meta-analyzed with additional genome-wide association study data sets. Results: We classified known AD loci into three categories, which might reflect the disease clinical heterogeneity. Vascular processes were only detected as a causal mechanism in probable AD. The meta-analysis strategy revealed the ANKRD31-rs4704171 and NDUFAF6-rs10098778 and confirmed SCIMP-rs7225151 and CD33-rs3865444. Discussion: The regulation of vasculature is a prominent causal component of probable AD. GR@ACE meta-analysis revealed novel AD genetic signals, strongly driven by the presence of clinical heterogeneity in the AD series

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele