The Proteomic Landscape of Centromeric Chromatin Reveals an Essential Role for the Ctf19CCAN Complex in Meiotic Kinetochore Assembly

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How does metal soil pollution change the plant mycobiome?

Microorganisms play a key role in plant adaptation to the environment. The aim of this study was to evaluate the effect of toxic metals present in the soil on the biodiversity of plant-related, endophytic mycobiota. The mycobiome of plants and soil from a Zn–Pb heap and a metal-free ruderal area were compared via Illumina sequencing of the ITS1 rDNA. The biodiversity of plants and fungi inhabiting mine dump substrate was lower than that of the metal free site. In the endosphere of Arabidopsis arenosa from the mine dump the number of endophytic fungal taxa was comparable to that in the reference population, but the community structure significantly differed. Agaricomycetes was the most notably limited class of fungi. The results of plant mycobiota evaluation from the field study were verified in terms of the role of toxic metals in plant endophytic fungi community assembly in a reconstruction experiment. The results presented in this study indicate that metal toxicity affects the structure of the plant mycobiota not by changing the pool of microorganisms available in the soil from which the fungal symbionts are recruited but most likely by altering plant and fungi behaviour and the organisms' preferences towards associating in symbiotic relationships.     

Development of the duct system during exocrine pancreas differentiation in the grass snake Natrix natrix (Lepidosauria,Serpentes)

We analyzed the development of the pancreatic ducts in grass snake Natrix natrix L. embryos with special focus on the three‐dimensional (3D)‐structure of the duct network, ultrastructural differentiation of ducts with attention to cell types and lumen formation. Our results indicated that the system of ducts in the embryonic pancreas of the grass snake can be divided into extralobular, intralobular, and intercalated ducts, similarly as in other vertebrate species. However, the pattern of branching was different from that in other vertebrates, which was related to the specific topography of the snake's internal organs. The process of duct remodeling in Natrix embryos began when the duct walls started to change from multilayered to single‐layered and ended together with tube formation. It began in the dorsal pancreatic bud and proceeded toward the caudal direction. The lumen of pancreatic ducts differentiated by cavitation because a population of centrally located cells was cleared through cell death resembling anoikis. During embryonic development in the pancreatic duct walls of the grass snake four types of cells were present, that is, principal, endocrine, goblet, and basal cells, which is different from other vertebrate species. The principal cells were electron‐dense, contained indented nuclei with abundant heterochromatin, microvilli and cilia, and were connected by interdigitations of lateral membranes and junctional complexes. The endocrine cells were electron‐translucent and some of them included endocrine granules. The goblet cells were filled with large granules with nonhomogeneous, moderately electron‐dense material. The basal cells were small, electron‐dense, and did not reach the duct lumen.     

Widespread habitat for Europe's largest herbivores,but poor connectivity limits recolonization

Aim

Several large-mammal species in Europe have recovered and recolonized parts of their historical ranges. Knowing where suitable habitat exists, and thus where range expansions are possible, is important for proactively promoting coexistence between people and large mammals in shared landscapes. We aimed to assess the opportunities and limitations for range expansions of Europe's two largest herbivores, the European bison (Bison bonasus) and moose (Alces alces).

Location

Central Europe.

Methods

We used large occurrence datasets from multiple populations and species distribution models to map environmentally suitable habitats for European bison and moose across Central Europe, and to assess human pressure inside the potential habitat. We then used circuit theory modeling to identify potential recolonization corridors.

Results

We found widespread suitable habitats for both European bison (>120,000 km²) and moose (>244,000 km²), suggesting substantial potential for range expansions. However, much habitat was associated with high human pressure (37% and 43% for European bison and moose, respectively), particularly in the west of Central Europe. We identified a strong east–west gradient of decreasing connectivity, with major barriers likely limiting natural recolonization in many areas.

Main conclusions

We identify major potential for restoring large herbivores and their functional roles in Europe's landscapes. However, we also highlight considerable challenges for conservation planning and wildlife management, including areas where recolonization likely leads to human–wildlife conflict and where barriers to movement prevent natural range expansion. Conservation measures restoring broad-scale connectivity are needed in order to allow European bison and moose to recolonize their historical ranges. Finally, our analyses and maps indicate suitable but isolated habitat patches that are unlikely to be colonized but are candidate locations for reintroductions to establish reservoir populations. More generally, our work emphasizes that transboundary cooperation is needed for restoring large herbivores and their ecological roles, and to foster coexistence with people in Europe's landscapes.     

High-Throughput Genotyping of Green Algal Mutants Reveals Random Distribution of Mutagenic Insertion Sites and Endonucleolytic Cleavage of Transforming DNA

A high-throughput genetic screening platform in a single-celled photosynthetic eukaryote would be a transformative addition to the plant biology toolbox. Here, we present ChlaMmeSeq (Chlamydomonas MmeI-based insertion site Sequencing), a tool for simultaneous mapping of tens of thousands of mutagenic insertion sites in the eukaryotic unicellular green alga Chlamydomonas reinhardtii. We first validated ChlaMmeSeq by in-depth characterization of individual insertion sites. We then applied ChlaMmeSeq to a mutant pool and mapped 11,478 insertions, covering 39% of annotated protein coding genes. We observe that insertions are distributed in a manner largely indistinguishable from random, indicating that mutants in nearly all genes can be obtained efficiently. The data reveal that sequence-specific endonucleolytic activities cleave the transforming DNA and allow us to propose a simple model to explain the origin of the poorly understood exogenous sequences that sometimes surround insertion sites. ChlaMmeSeq is quantitatively reproducible, enabling its use for pooled enrichment screens and for the generation of indexed mutant libraries. Additionally, ChlaMmeSeq allows genotyping of hits from Chlamydomonas screens on an unprecedented scale, opening the door to comprehensive identification of genes with roles in photosynthesis, algal lipid metabolism, the algal carbon-concentrating mechanism, phototaxis, the biogenesis and function of cilia, and other processes for which C. reinhardtii is a leading model system.     

The microbial threat: Can rare earths help?

Despite an ever increasing demand for reliable and cheap methods in the detection and quantification of microbes, surprisingly few investigations have explored or utilized the luminescence of rare earths in the microbial context, neither in conventional, that is, plating and microscopic imaging techniques, nor in advanced methods like fluorescence flow cytometry. We have thus investigated the potential of some rare earth complexes and hybrid materials for microbiological analysis. We found fairly simple procedures for internal staining (dyes inside the bacterial cell) and external staining (dyes on the cell surface). The present paper is predominantly relying on microscopic imaging and luminescence spectroscopies (excitation, emission, decay times), but also evaluates model rare earth microspheres to estimate an eventual rare earth based stain for a fast and sensitive bacteria enumeration with luminescence flow cytometry.     

How the Geomagnetic Field Influences Life on Earth – An Integrated Approach to Geomagnetobiology

Origins of Life and Evolution of Biospheres - Earth is one of the inner planets of the Solar System, but – unlike the others – it has an oxidising atmosphere, relatively stable...