Evolutionary relationships among bifidobacteria and their hosts and environments.

BACKGROUND:The assembly of animal microbiomes is influenced by multiple environmental factors and host genetics, although the relative importance of these factors remains unclear. Bifidobacteria (genus Bifidobacterium, phylum Actinobacteria) are common first colonizers of gut microbiomes in humans and inhabit other mammals, social insects, food, and sewages. In humans, the presence of bifidobacteria in the gut has been correlated with health-promoting benefits. Here, we compared the genome sequences of a subset of the over 400 Bifidobacterium strains publicly available to investigate the adaptation of bifidobacteria diversity. We tested 1) whether bifidobacteria show a phylogenetic signal with their isolation sources (hosts and environments) and 2) whether key traits encoded by the bifidobacteria genomes depend on the host or environment from which they were isolated. We analyzed Bifidobacterium genomes available in the PATRIC and NCBI repositories and identified the hosts and/or environment from which they were isolated. A multilocus phylogenetic analysis was conducted to compare the genetic relatedness the strains harbored by different hosts and environments. Furthermore, we examined differences in genomic traits and genes related to amino acid biosynthesis and degradation of carbohydrates. RESULTS:We found that bifidobacteria diversity appears to have evolved with their hosts as strains isolated from the same host were non-randomly associated with their phylogenetic relatedness. Moreover, bifidobacteria isolated from different sources displayed differences in genomic traits such as genome size and accessory gene composition and on particular traits related to amino acid production and degradation of carbohydrates. In contrast, when analyzing diversity within human-derived bifidobacteria, we observed no phylogenetic signal or differences on specific traits (amino acid biosynthesis genes and CAZymes). CONCLUSIONS:Overall, our study shows that bifidobacteria diversity is strongly adapted to specific hosts and environments and that several genomic traits were associated with their isolation sources. However, this signal is not observed in human-derived strains alone. Looking into the genomic signatures of bifidobacteria strains in different environments can give insights into how this bacterial group adapts to their environment and what types of traits are important for these adaptations

Prochlorococcus, Synechococcus and picoeukaryotic phytoplankton abundance climatology in the global ocean from quantitative niche models.

Dataset: phytoplankton climatologyProchlorococcus, Synechococcus and picoeukaryotic phytoplankton estimated mean cell abundance (cells/ml) in 1-degree grids for 25 layers from 0m to 200 m depth. Cell abundance was estimated with quantitative niche models for each lineage (Flombaum et al., 2013; Flombaum et al., 2020), inputs from the monthly mean of temperature and nitrate from the World Ocean Atlas, and PAR from MODIS-Aqua Level-3 Mapped Photosynthetically Available Radiation Data Version 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/811147NSF Division of Ocean Sciences (NSF OCE) OCE-1848576, Agencia Nacional de Promoción Científica y Tecnológica () PICT-2017-3020, Universidad de Buenos Aires () UBACyT 20020170100620B

Theoretical study of impurity-induced magnetism in FeSe

Experimental evidence suggests that FeSe is close to a magnetic instability, and recent scanning tunneling microscopy (STM) measurements on FeSe multilayer films have revealed stripe order locally pinned near defect sites. Motivated by these findings, we perform a theoretical study of locally induced magnetic order near nonmagnetic impurities in a model relevant for FeSe. We find that relatively weak repulsive impurities indeed are capable of generating short-range magnetism, and explain the driving mechanism for the local order by resonant eg-orbital states. In addition, we investigate the importance of orbital-selective self-energy effects relevant for Hund's metals, and show how the structure of the induced magnetization cloud gets modified by orbital selectivity. Finally, we make concrete connection to STM measurements of iron-based superconductors by symmetry arguments of the induced magnetic order, and the basic properties of the Fe Wannier functions relevant for tunneling spectroscopy.Comment: 10 pages, 4 figure

Community Managed Water Projects and Poverty Reduction: A Case Study from Guatemala

This paper will discuss poverty and quality of life indicators such as income, education, access to water, water quality, health and community participation, in relation to two community managed water projects in the rural communities of Piedad II and Colonia Belen, located in the western region of Guatemala. Both projects were part of the United Nations Development Program\u27s Small Grants Program\u27s Community Water Initiative. A household survey was developed and given to women project beneficiaries in the summer of 2007 in order to gather data on the above indicators. At the time of this study, the project had already been completed in Colonia Belen, but was still under construction in Piedad II. The two communities are distinct, with Colonia Belen being smaller, more isolated, significantly poorer, and its access to water is much more limited in comparison to Piedad II. Data gathered in Colonia Belen is very uniform as all households are affected by the remote location and limited natural and economic resources of the region. Despite the high project costs in Colonia Belen (US$344.47 per person, more than half the cost of the project in Piedad II of US$115.02 per person), recipients may be willing to pay more because of greater tangible and perceived benefits, such as an average of 110 minutes of time saved by each person collecting water every day, in contrast to the 55 minutes saved by those collecting water in Piedad II. Even though Colonia Belen had access to sufficient amounts of potable water as a result of the new project, they were only consuming 33 liters of water per person per day, as opposed to those living in Piedad II who were consuming 186 liters of water per person per day before the project was completed. This paper concludes with a brief analysis of the costs and benefits of each project, recommendations for each project and the Community Water Initiative program in general, and a discussion of the relationship between different indicators of poverty

The big slice phenomenon in Banach spaces. Diameter 2 properties, Daugavet- and delta-points

Paper IV is excluded from the dissertation until it will be published.Preliminary theory will be presented prior to each result. We begin, in Subsection 1.2.1, by discussing Müntz spaces, which is the focus of the two first papers, “Two properties of Müntz spaces” and “Octahedrality and Müntz spaces”. In Subsection 1.2.2, we then discuss diameter two properties which is the recurring theme throughout the thesis. We end the summary, with Subsection 1.2.3, by presenting the results related to Daugavet- and delta-points, which form the focus of the papers “Daugavet- and delta-points in Banach spaces with unconditional bases” and “Delta-points in Banach spaces generated by adequate families”. All the results are stated without proofs, but their origin is referenced where their proofs can be found in full detail. The notation and terminology used throughout the thesis is standard (see e.g. [AK06]). If X is a Banach space, then Bx, Sx and X* denote the unit ball, unit sphere and topological dual space, respectively. The convex hull of A of a subset of X is denoted conv(A) and the linear span by span(A). The norm- and weak-closure of A will be denoted A and Aw, respectively.publishedVersio