Flora Project Research Articles

Q2-metnet: QIIME2 package to analyze 16S rRNA data via high-quality metabolic reconstructions of the human gut microbiota.

16S rRNA gene sequencing is the most frequent approach for the characterization of the human gut microbiota. Despite different efforts in the literature, the inference of functional and metabolic interpretations from 16S rRNA gene sequencing data is still a challenging task. High-quality metabolic reconstructions of the human gut microbiota, such as AGORA and AGREDA, constitute a curated resource to improve functional inference from 16S rRNA data, but they are not typically integrated into standard bioinformatics tools. Here, we present q2-metnet, a QIIME2 plugin that enables the contextualization of 16S rRNA gene sequencing data into AGORA and AGREDA. In particular, based on relative abundances of taxa, q2-metnet determines normalized activity scores for the reactions and subsystems involved in the selected metabolic reconstruction. Using these scores, q2-metnet allows the user to conduct differential activity analysis for reactions and subsystems, as well as exploratory analysis using PCA and hierarchical clustering. We apply q2-metnet to a dataset from our group that involves 16S rRNA data from stool samples from lean, allergic to cow's milk, obese and celiac children, and the Belgian Flemish Gut Flora Project cohort, which includes faecal 16S rRNA data from obese and normal-weight adult individuals. In the first case, q2-metnet outperforms existing algorithms in separating different clinical conditions based on predicted pathway abundances and subsystem scores. In the second case, q2-metnet complements competing approaches in predicting functional alterations in the gut microbiota of obese individuals. Overall, q2-metnet constitutes a powerful bioinformatics tool to provide metabolic context to 16S rRNA data from the human gut microbiota. Python code of q2-metnet is available in https://github.com/PlanesLab/q2-metnet and https://figshare.com/articles/dataset/q2-metnet_package/26180446. Supplementary data are available at Bioinformatics online.

South America holds the greatest diversity of native daisies (Asteraceae) in the world: an updated catalogue supporting continental-scale conservation.

Asteraceae is the world's richest plant family and is found on all continents, in environments ranging from the coast to the highest mountains. The family shows all growth forms and, as in other angiosperm families, species richness is concentrated in tropical regions. South America has the highest diversity of Asteraceae in the world, yet taxonomic and distributional knowledge gaps remain. This study compiles an updated catalog of Asteraceae native to South America, based on national and regional checklists and ongoing large-scale flora projects. The resulting checklist includes a total of 6,940 species and 564 genera native to South America to date, which represent about a quarter of the family's global diversity. Countries already considered to be megadiverse show the greatest diversity, such as Brazil with 2,095 species, followed by Peru (1,588), Argentina (1,377), and Colombia (1,244), with this diversity mainly focused on the Brazilian Highlands and the Andes. Species endemism also peaks in Brazil, but Sørensen distances reveal the Chilean flora to be eminently different from the rest of the continent. Tribes better represented in the continent are Eupatorieae, Senecioneae and Astereae, also with a remarkably presence of entirely South American subfamilies representing earliest diverging lineages of the Asteraceae, such as Barnadesioideae, Wunderlichioideae, Famatinanthoideae, and Stifftioideae. It is estimated that the discovery and description curves have not yet stabilized, and the number of species is likely to increase by 5 to 10% in the coming years, posing major challenges to continental-scale conservation.

Botanical Assessment of Remnant Floodplain Habitats Along Plaster Creek, Kent County, Michigan: Assessing Changes Since the 1890s

Plaster Creek, a tributary of the Grand River, drains a 58-square mile watershed in Kent County, Michigan. Its headwaters originate in the agriculturally dominated southwestern portion of the county, and then it meanders through residential, commercial, and urban areas of Kentwood and Grand Rapids before it empties into the Grand River about one mile south of downtown Grand Rapids. Much of Plaster Creek’s original floodplain, like the rest of its watershed, has been drastically altered and degraded over time due to the development of residential neighborhoods, commercial properties, agriculture, and industrial zones. Floodplains house unique assemblages of Michigan’s native biodiversity and sustain stream and watershed health, warranting their preservation and restoration. Over several seasons, Calvin University Herbarium’s Emma Cole Grand Rapids Flora Project inventoried seven remnant floodplain sites along Plaster Creek from near its source in Gaines Township to downstream areas within the City of Grand Rapids. A total of 438 species of vascular plants were documented for the combined seven floodplains, of which 341 (77.9%) are native. Floristic Quality Assessments were calculated for each of the sites with values ranging from a Total Floristic Quality Index (FQI) of 30.4 (Total Mean C = 2.8) at the smallest site with only 93 native species (78.7%), to a Total FQI of 52.7 (Total Mean C = 3.6) at the Ken-O-Sha Park floodplain, with 176 (82.2%) native species. The Stanaback Park floodplain had a similar number of native species, 174 (80.9%), and a Total FQI of 48.4 (Total Mean C = 3.3). In order to make comparisons with floristic information compiled by Emma Cole in the 1890s, a Floristic Quality Assessment was calculated based on 65 species (98.5% native) collected and reported by Cole (1901) as occurring along Plaster Creek. The Total FQI of Cole’s list was 48.4 (Total Mean C = 6.0), and 27 of her species have a high level of fidelity to a narrow range of ecological conditions, five of which today hold Special Concern, Threatened, or Endangered status in Michigan. By comparing our inventory findings with the floristic information gathered by Cole, this study highlights changes that have taken place in the Plaster Creek floodplain over the past 120+ years, describes the present-day condition of Plaster Creek’s floodplains, and can be used to inform future ecological restoration efforts along this and other local creeks.

Dual UHPLC-HRMS Metabolomics and Lipidomics and Automated Data Processing Workflow for Comprehensive High-Throughput Gut Phenotyping.

In recent years, feces has surfaced as the matrix of choice for investigating the gut microbiome-health axis because of its non-invasive sampling and the unique reflection it offers of an individual's lifestyle. In cohort studies where the number of samples required is large, but availability is scarce, a clear need exists for high-throughput analyses. Such analyses should combine a wide physicochemical range of molecules with a minimal amount of sample and resources and downstream data processing workflows that are as automated and time efficient as possible. We present a dual fecal extraction and ultra high performance liquid chromatography-high resolution-quadrupole-orbitrap-mass spectrometry (UHPLC-HR-Q-Orbitrap-MS)-based workflow that enables widely targeted and untargeted metabolome and lipidome analysis. A total of 836 in-house standards were analyzed, of which 360 metabolites and 132 lipids were consequently detected in feces. Their targeted profiling was validated successfully with respect to repeatability (78% CV < 20%), reproducibility (82% CV < 20%), and linearity (81% R2 > 0.9), while also enabling holistic untargeted fingerprinting (15,319 features, CV < 30%). To automate targeted processing, we optimized an R-based targeted peak extraction (TaPEx) algorithm relying on a database comprising retention time and mass-to-charge ratio (360 metabolites and 132 lipids), with batch-specific quality control curation. The latter was benchmarked toward vendor-specific targeted and untargeted software and our isotopologue parameter optimization/XCMS-based untargeted pipeline in LifeLines Deep cohort samples (n = 97). TaPEx clearly outperformed the untargeted approaches (81.3 vs 56.7-66.0% compounds detected). Finally, our novel dual fecal metabolomics-lipidomics-TaPEx method was successfully applied to Flemish Gut Flora Project cohort (n = 292) samples, leading to a sample-to-result time reduction of 60%.

Flora of Espírito Santo: Celastroideae (Celastraceae)

Abstract Here we present a taxonomic treatment of the subfamily Celastroideae (Celastraceae) in the state of Espírito Santo, southeastern Brazil, as a part of the ongoing project Flora do Espírito Santo. The work is based on analyses of herbaria specimens and fieldwork since 2012. Two genera and thirteen species are reported for Espírito Santo, covering all the vegetation formations found in the state. Celastrus is represented by one species, C. liebmannii, the unique climbing species of the subfamily in Brazil. Monteverdia are shrubs and trees characterized by fruits 2-valved, pericarp coriaceous and white aril. The genus is represented by twelve species, corresponding nearly to one third of the Brazilian species. Celastrus liebmannii is formally reported by the first time to Espírito Santo. Morphological descriptions, comments, color photographs plates, and identification keys for genera and Monteverdia species are provided.

Large-scale correlation analysis of deep venous thrombosis and gut microbiota.

Although previous studies have shown that gut microbiota may be involved in the occurrence of deep venous thrombosis (DVT), the specific link between the two remains unclear. The present study aimed to explore this question from a genetic perspective. Genome-wide association study (GWAS) summary data of DVT were obtained from the UK Biobank (N = 9,059). GWAS summary data of the gut microbiota were obtained from the Flemish Gut Flora Project (N = 2,223) and two German cohorts (FoCus, N = 950; PopGen, N = 717). All the participants were of European ancestry. Linkage disequilibrium score (LDSC) regression has great potential for analyzing the heritability of disease or character traits. LDSC regression was used to analyze the genetic correlation between DVT and the gut microbiota based on the GWAS summary data obtained from previous studies. Mendelian randomization (MR) was used to analyze the genetic causal relationship between DVT and the gut microbiota. We used the random effects inverse variance weighted, MR Egger, weighted median, simple mode, and weighted mode to perform MR analysis. We performed a sensitivity analysis of the MR analysis results by examining heterogeneity and horizontal pleiotropy. Linkage disequilibrium score analysis showed that Streptococcaceae (correlation coefficient = -0.542, SE = 0.237, P = 0.022), Dialister (correlation coefficient = -0.623, SE = 0.316, P = 0.049), Streptococcus (correlation coefficient = -0.576, SE = 0.264, P = 0.029), and Lactobacillales (correlation coefficient = -0.484, SE = 0.237, P = 0.042) had suggestive genetic correlation with DVT. In addition, the MR analysis showed that Streptococcaceae had a positive genetic causal relationship with DVT (P = 0.027, OR = 1.005). There was no heterogeneity or horizontal pleiotropy in the MR analysis (P > 0.05). In this study, four gut microbes (Streptococcaceae, Dialister Streptococcus, Lactobacillales) had suggestive genetic correlations with DVT, and Streptococcaceae had a positive causal relationship with DVT. Our findings provide a new research direction for the further study of and prevention of DVT.

Lectotypification of Indochinese Ebenaceae published by P. H. Lecomte (1925-1930)

The Ebenaceae of Cambodia, Laos, and Vietnam have yet to be treated in the ongoing Flora projects. The first step towards an updated account is the resolution of the nomenclatural status of the taxa known to occur in the region. Here we designate lectotypes for 50 taxa described by Lecomte between 1925-1930. We also provide currently accepted names for these species.

Successional Stages in Infant Gut Microbiota Maturation.

ABSTRACTDisturbances in the primary colonization of the infant gut can result in lifelong consequences and have been associated with a range of host conditions. Although early-life factors have been shown to affect infant gut microbiota development, our current understanding of human gut colonization in early life remains limited. To gain more insights into the unique dynamics of this rapidly evolving ecosystem, we investigated the microbiota over the first year of life in eight densely sampled infants (n = 303 total samples). To evaluate the gut microbiota maturation transition toward an adult configuration, we compared the microbiome composition of the infants to that of the Flemish Gut Flora Project (FGFP) population (n = 1,106). We observed the infant gut microbiota to mature through three distinct, conserved stages of ecosystem development. Across these successional gut microbiota maturation stages, the genus predominance was observed to shift from Escherichia over Bifidobacterium to Bacteroides. Both disease and antibiotic treatment were observed to be associated occasionally with gut microbiota maturation stage regression, a transient setback in microbiota maturation dynamics. Although the studied microbiota trajectories evolved to more adult-like constellations, microbiome community typing against the background of the FGFP cohort clustered all infant samples within the (in adults) potentially dysbiotic Bacteroides 2 (Bact2) enterotype. We confirmed the similarities between infant gut microbial colonization and adult dysbiosis. Profound knowledge about the primary gut colonization process in infants might provide crucial insights into how the secondary colonization of a dysbiotic adult gut can be redirected.

Preliminary placement and new records of an overlooked Amazonian tree, Christiana mennegae (Malvaceae).

Christiana mennegae is a phylogenetically enigmatic taxon and represents a case in point of a species whose presence escaped the radar of the Amazon lists and the Brazilian Flora project. Here we expand its distribution by adding new records from Peru and overlooked ones from Brazil. To investigate its phylogenetic placement in the Brownlowioideae, part of the rbcL gene of the plastid and the intergenic ITS2 region were sequenced. Macro- and micro-morphological investigation of features of C. mennegae using SEM of foliar, flower, fruit and seed structures are presented. A lectotype for the name is designated here. The morphology of trichomes revealed five types of trichomes ranging from glandular to branched and unbranched and we also report stomata on the seed surface for the first time in Brownlowioideae. Christiana mennegae and C. africana were recovered as sister species in the phylogenetic analysis, albeit with low to moderate support, and more species of this and closely related genera must be sampled and analyzed in order to obtain a clearer picture of the group’s affinities and relationships. We provide an update of its conservation status from Vulnerable to Least Concern. We also highlight the need for investment in the digitization of biological collections, botanical capacity building at the local level and the importance of the availability of online literature to speed the study of Amazonian plant diversity.

FLEXiGUT: Rationale for exposomics associations with chronic low-grade gut inflammation

FLEXiGUT is the first large-scale exposomics study focused on chronic low-grade inflammation. It aims to characterize human life course environmental exposure to assess and validate its impact on gut inflammation and related biological processes and diseases. The cumulative influences of environmental and food contaminants throughout the lifespan on certain biological responses related to chronic gut inflammation will be investigated in two Flemish prospective cohorts, namely the “ENVIRONAGE birth cohort”, which provides follow-up from gestation to early childhood, and the “Flemish Gut Flora Project longitudinal cohort”, a cohort of adults. The exposome will be characterised through biomonitoring of legacy and emerging contaminants, mycotoxins and markers of air pollution, by analysing the available metadata on nutrition, location and activity, and by applying state-of-the-art -omics techniques, including metagenomics, metabolomics and DNA adductomics, as well as the assessment of telomere length and measurement of inflammatory markers, to encompass both exposure and effect. Associations between exposures and health outcomes will be uncovered using an integrated -omics data analysis framework comprising data exploration, pre-processing, dimensionality reduction and data mining, combined with machine learning-based pathway analysis approaches. This is expected to lead to a more profound insight in mechanisms underlying disease progression (e.g. metabolic disorders, food allergies, gastrointestinal cancers) and/or accelerated biological ageing.

Dysosmobacter welbionis is a newly isolated human commensal bacterium preventing diet-induced obesity and metabolic disorders in mice

ObjectiveTo investigate the abundance and the prevalence of Dysosmobacter welbionis J115T, a novel butyrate-producing bacterium isolated from the human gut both in the general population and in subjects with metabolic...

Abstract GS2-06: Exploring the causal role of the human gut microbiome in breast cancer risk using mendelian randomization

Abstract Background: Variation in the human gut microbiome may influence cancer progression and therapy response through various mechanisms including modulation of both immune and cell signalling pathways. Whilst observational epidemiological studies have provided evidence that the gut microbiome may play a role in cancer risk, such studies are prone to residual confounding, reverse causation, and other forms of bias. Therefore, the nature of these associations still remains unclear. Mendelian randomization (MR) is a causal methodology that uses genetic variants as instruments (“proxies”) for risk factors to eliminate such biases when questioning causality in observational epidemiological associations. The statistical power and precision of MR analyses can be increased by employing a “two-sample MR” (2SMR) framework in which summary data – usually from large, independent, genome-wide association studies (GWASs) reporting associations of genetic variants with exposures (here, the gut microbiome) and outcomes (here, cancer) – are synthesised to estimate causal effects of each exposure on each outcome of interest. In this study, we utilised 2SMR to interrogate causal relationships between the gut microbiome and breast cancer (BC) risk using the largest published GWASs of the gut microbiome and of clinically utilised subtypes of BC. Methods: We performed 2SMR using summary-level data from the GWAS of the host genetic contribution to gut microbiome variation amongst European individuals (the Flemish Gut Flora Project and two German cohorts (n=3890)) combined with summary-level data from the GWAS of BC risk (Breast Cancer Association Consortium (133,384 cases stratified by Luminal A, Luminal B, Human Epidermal Growth Factor 2 (Her2) positive, Her2 negative and triple negative status and 113,789 controls, plus 18,908 BRCA1 mutation carriers (9,414 with BC)). Sensitivity analyses were also conducted to assess pleiotropy of genetic variants on BC risk, independent of gut microbiota. Analyses were conducted in R Studio using the TwoSampleMR and the MR-TRYX packages. Results: Of the 14 microbial traits (MTs) with evidence for a host genetic contribution in the GWAS of the gut microbiome, we found evidence that abundance of a genus within a certain bacterial order decreased the risk of triple negative BC (odds ratio per standard deviation increase: 0.84; 95% CI: 0.71, 0.9; p=0.03). In addition, we demonstrated that the risk of all molecular subtypes of BC may be altered by variation in these MTs, and that these relationships differed according to subtype. Sensitivity analyses demonstrated that pleiotropy was unlikely to explain these relationships Conclusions: In our study, we utilised two recent and novel GWASs in an MR context to appraise causality in relationships between the gut microbiome and BC risk and found evidence that certain bacteria may alter BC risk, effects of which vary according to molecular subtype. These important results generate hypotheses about mechanisms underlying the causal biology of BC subtypes and potentially facilitate the design of BC risk-reducing interventions and prevention strategies. Citation Format: Tim Robinson, Grace Edmunds, Bryony Hayes, Kaitlin Wade. Exploring the causal role of the human gut microbiome in breast cancer risk using mendelian randomization [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS2-06.

Collecting Chinese Flora: Eighteenth- to Nineteenth-Century Sino-British Scientific and Cultural Exchanges as Seen through British Collections of China Trade Botanical Paintings

Abstract In the eighteenth to nineteenth century, British botanists collected thousands of Chinese plants to advance their knowledge of natural history. John Bradby Blake was the first British botanist to systematically collect Chinese plants in the 1770s, a time when foreigners could only access Guangzhou (Canton). This article demonstrates that Blake’s Chinese flora project heavily relied on the work of Chinese ‘go-betweens’, notably painter Mak Sau, who painted Chinese plants in a scientifically accurate manner. The genre of Canton Trade botanical paintings is a hybrid between European botanical tradition and Chinese bird-and-flower paintings that had previously been difficult to analyse owing to the lack of chronological evidence. Thanks to new data uncovered in different Blake collections, this article begins to untangle the chronology of these botanical paintings, and in the process uncovers the untold agency of Chinese ‘go-betweens’ in early Sino-Western scientific and cultural exchanges.

Genome-wide associations of human gut microbiome variation and implications for causal inference analyses.

Recent population-based1–4 and clinical studies5 have identified a range of factors associated with human gut microbiome variation. Murine quantitative trait loci6, human twin studies7 and microbiome genome-wide association studies (mGWAS)1,3,8–12 have provided evidence for genetic contributions to microbiome composition. Despite this, there is still poor overlap in genetic association across human studies. Using appropriate taxon-specific models along with support from independent cohorts, we show association between human host genotype and gut microbiome variation. We also suggest that interpretation of applied analyses using genetic associations is complicated by the likely overlap between genetic contributions and heritable components of host environment. Using fecal derived 16S rRNA gene sequences and host genotype data from the Flemish Gut Flora Project (FGFP, n=2223) and two German cohorts (FoCus, n=950, PopGen n=717), we identify genetic associations involving multiple microbial traits (MTs). Two of these associations achieved a study-level p-value threshold of 1.57×10−10; an association between Ruminococcus and rs150018970 near RAPGEF1 on chromosome 9, and between Coprococcus and rs561177583 within LINC01787 on chromosome 1. Exploratory analysis was undertaken using 11 other genome-wide associations with strong evidence for association (p-value < 2.5×10−08) and a previously reported signal of association between rs4988235 (MCM6/LCT) and Bifidobacterium. Across these 14 SNPs there was evidence of signal overlap with other GWAS including those for age at menarche and cardiometabolic traits. Mendelian randomization (MR) analysis was able to estimate associations between MTs and disease (including Bifidobacterium and body composition), however in the absence of clear microbiome driven effects, caution is needed in interpretation. Overall, this work marks a growing catalog of genetic associations which will provide insight into the contribution of host genotype to gut microbiome. Despite this, the uncertain origin of association signals will likely complicate future work looking to dissect function or use associations for causal inference analysis.

Statin therapy is associated with lower prevalence of gut microbiota dysbiosis.

Microbiome community typing analyses have recently identified the Bacteroides2 (Bact2) enterotype, an intestinal microbiota configuration that is associated with systemic inflammation and has a high prevalence in loose stools in humans1,2. Bact2 is characterized by a high proportion of Bacteroides, a low proportion of Faecalibacterium and low microbial cell densities1,2, and its prevalence varies from 13% in a general population cohort to as high as 78% in patients with inflammatory bowel disease2. Reported changes in stool consistency3 and inflammation status4 during the progression towards obesity and metabolic comorbidities led us to propose that these developments might similarly correlate with an increased prevalence of the potentially dysbiotic Bact2 enterotype. Here, by exploring obesity-associated microbiota alterations in the quantitative faecal metagenomes of the cross-sectional MetaCardis Body Mass Index Spectrum cohort (n=888), we identify statin therapy as a key covariate of microbiome diversification. By focusing on a subcohort of participants that are not medicated with statins, we find that the prevalence of Bact2 correlates with body mass index, increasing from 3.90% in lean or overweight participants to 17.73% in obese participants. Systemic inflammation levels in Bact2-enterotyped individuals are higher than predicted on the basis of their obesity status, indicative of Bact2 as a dysbiotic microbiome constellation. We also observe that obesity-associated microbiota dysbiosis is negatively associated with statin treatment, resulting in a lower Bact2 prevalence of 5.88% in statin-medicated obese participants. This finding is validated in both the accompanying MetaCardis cardiovascular disease dataset (n = 282) and the independent Flemish Gut Flora Project population cohort (n=2,345). The potential benefits of statins in this context will require further evaluation in a prospective clinical trial to ascertain whether the effect is reproducible in a randomized population and before considering their application as microbiota-modulating therapeutics.

Flora of Reserva Ducke, Amazonas, Brazil: Linaceae

Abstract This study defines and characterizes the species of Linaceae occurring in Reserva Ducke. We analyzed material collected mainly during the Project Flora of Reserva Ducke. Two genera, each with one species, are recorded: Hebepetalum humiriifolium and Roucheria columbiana. We present species descriptions, taxonomic comments, illustrations, habitat information, geographic distribution and an identification key to species of Linaceae.

Progress on Southeast Asia’s Flora projects

Progress on Southeast Asia’s Flora projects

New records of Digitaria filiformis var. laeviglumis (Paniceae, Panicoideae, Poaceae) for the Flora del Bajío and Durango, Mexico

Background and Aims: Since its publication in 1920, Digitaria filiformis var. laeviglumis had been considered as an endangered taxon endemic to New Hampshire, USA. However, a recent inventory of the grasses of Mexico showed that it also occurs outside its type locality. New findings for the ongoing project Flora del Bajío have yielded additional new records. The objective of this work is to report this taxon from the Mexican states of Michoacán and Durango, increasing the number of known localities of Digitaria filiformis var. laeviglumis.Methods: Online databases and herbaria were reviewed. Botanical herbarium specimens were collected in the state of Michoacán.Key results: Digitaria filiformis var. laeviglumis is reported as new for the Flora del Bajío in the state of Michoacán, as well as from a herbarium specimen from Durango which has both var. laeviglumis and var. filiformis mounted on the same sheet and that was misplaced among other specimens.Conclusions: With the addition of this variety, the number of taxa in the subfamily Panicoideae increases for the Flora del Bajío and the state Durango. With these findings there are more intermediate localities between the northern and southern range for this variety.

The neuroactive potential of the human gut microbiota in quality of life and depression

The relationship between gut microbial metabolism and mental health is one of the most intriguing and controversial topics in microbiome research. Bidirectional microbiota-gut-brain communication has mostly been explored in animal models, with human research lagging behind. Large-scale metagenomics studies could facilitate the translational process, but their interpretation is hampered by a lack of dedicated reference databases and tools to study the microbial neuroactive potential. Surveying a large microbiome population cohort (Flemish Gut Flora Project, n = 1,054) with validation in independent data sets (ntotal = 1,070), we studied how microbiome features correlate with host quality of life and depression. Butyrate-producing Faecalibacterium and Coprococcus bacteria were consistently associated with higher quality of life indicators. Together with Dialister, Coprococcus spp. were also depleted in depression, even after correcting for the confounding effects of antidepressants. Using a module-based analytical framework, we assembled a catalogue of neuroactive potential of sequenced gut prokaryotes. Gut-brain module analysis of faecal metagenomes identified the microbial synthesis potential of the dopamine metabolite 3,4-dihydroxyphenylacetic acid as correlating positively with mental quality of life and indicated a potential role of microbial γ-aminobutyric acid production in depression. Our results provide population-scale evidence for microbiome links to mental health, while emphasizing confounder importance.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Poaceae

Resumo Este trabalho apresenta um tratamento taxonômico para a família Poaceae nas cangas das Serra dos Carajás, Pará, Brasil. O artigo foi preparado de acordo com o escopo do projeto Flora das Cangas da Serra dos Carajás, com base no estudo de espécimes dos herbários BHCB, MG e UB. Foram levantadas 87 espécies, pertencentes a 37 gêneros. Dessas, Axonopus carajasensis, Paspalum cangarum, P. carajasense e Sporobolus multiramosus são consideradas endêmicas das cangas de Carajás; duas espécies novas estão em fase de publicação (uma de Paspalum e uma de Hildaea); e uma espécie de Trichanthecium está em estudo para determinar sua identidade taxonômica. Seis espécies são registradas no estado do Pará pela priemira vez. São fornecidas descrições morfológicas, chaves de identificação, ilustrações das espiguetas, pranchas fotográficas, distribuição geográfica e comentários para as espécies tratadas.