Search

Background: Our understanding of C storage in soils lacks insights investigating organic matter (OM) depletion, often studied in bare fallow systems. The content of coarse rock fragments is often excluded, whereas it may affect C storage. Aims: We aim to contribute to a better understanding of the impact of bare fallow on C storage mechanisms in the soil as influenced by its coarse rock fragment contents. We investigated whether bare fallow induced a depletion of C in OM fractions and analyzed to which extent this affected soil aggregate size distribution and the C loading of the clay‐sized fraction. Methods: A comparison of 14 years bare fallow management with adjacent cropped soils located in Selhausen (Germany) provided a gradient of coarse rock fragments of 34%–71%, from which sites with three different fine earth (FE) contents were compared. Across the FE gradient, we isolated particulate OM and mineral‐associated OM fractions, obtained microaggregate and macroaggregate size fractions, and quantified the C loading. Results: Bare fallow management induced an OM depletion at lower contents of FE. There, the management influence was more concentrated onto less FE volume. The contribution of both particulate and mineral‐associated OM fractions to the C in the low‐FE soils decreased. The C loading increased under bare fallow, compared to cropped soil. In the low‐FE soil, we also found less macroaggregates, whereas the C content decreased in some microaggregate size fractions. Conclusions: A high content of coarse rock fragments can enhance OM depletion decreasing mineral‐associated and particulate C under bare fallow. [ABSTRACT FROM AUTHOR]

The functions of soils are intimately linked to their three‐dimensional pore space and the associated biogeochemical interfaces, mirrored in the complex structure that developed during pedogenesis. Under stress overload, soil disintegrates into smaller compound structures, conventionally named aggregates. Microaggregates (<250 µm) are recognized as the most stable soil structural units. They are built of mineral, organic, and biotic materials, provide habitats for a vast diversity of microorganisms, and are closely involved in the cycling of matter and energy. However, exploring the architecture of soil microaggregates and their linkage to soil functions remains a challenging but demanding scientific endeavor. With the advent of complementary spectromicroscopic and tomographic techniques, we can now assess and visualize the size, composition, and porosity of microaggregates and the spatial arrangement of their interior building units. Their combinations with advanced experimental pedology, multi‐isotope labeling experiments, and computational approaches pave the way to investigate microaggregate turnover and stability, explore their role in element cycling, and unravel the intricate linkage between structure and function. However, spectromicroscopic techniques operate at different scales and resolutions, and have specific requirements for sample preparation and microaggregate isolation; hence, special attention must be paid to both the separation of microaggregates in a reproducible manner and the synopsis of the geography of information that originates from the diverse complementary instrumental techniques. The latter calls for further development of strategies for synlocation and synscaling beyond the present state of correlative analysis. Here, we present examples of recent scientific progress and review both options and challenges of the joint application of cutting‐edge techniques to achieve a sophisticated picture of the properties and functions of soil microaggregates. [ABSTRACT FROM AUTHOR]

Background: Organic matter (OM) serves as substrate for heterotrophic microbial growth. Soil structure supports microbial life by providing various niches for colonization. Microorganisms in turn contribute to soil structure formation. Aims: We aim to understand how OM of different origin and soil texture affect prokaryotic community structure and the implications on early‐stage soil structure formation. Methods: An artificial soil incubation experiment was conducted with different types of OM, including bacterial necromass and particulate organic matter (POM) of larger or smaller size (sPOM). The mineral composition was modified to obtain a clay loam, loam, and sandy loam texture. The abundance and composition of a natural microbial inoculum were determined after 30 days of incubation by real‐time PCR and 16S rRNA gene sequencing, respectively. Results: The different OM types had a stronger effect on the prokaryotic community structure and abundance than texture. The necromass treatment supported the most distinct prokaryotic community with the highest abundance and lowest diversity, as well as the most intense formation of water‐stable microaggregates in comparison to POM and sPOM treatments. Abundant bacterial taxa in all treatments are known to include extracellular polymeric substance producers, indicating that functional redundancy warrants aggregation by gluing agents. Texture‐related effects were most consistent in the POM treatment, where larger prokaryotic populations were observed in the coarser‐textured soils with fewer but larger soil pores and lower soil water content. Conclusions: Differences in prokaryotic community structure and abundance due to OM source indicate that aggregation is dependent on different ecological strategists, a POM‐degrading population that promotes aggregation and contributes to necromass formation, and a necromass‐degrading consortium in which bacteria play a major role. [ABSTRACT FROM AUTHOR]

Background: Percolating dissolved organic matter (DOM) from the topsoil is considered the main source of subsoil organic carbon (OC) in temperate soils, but knowledge about its influence on OC storage and structure‐forming processes is limited. Aims: We conducted a 30‐day incubation experiment with artificial soils to study the effects of percolating DOM and soil texture on OC turnover and initial structure formation. Methods: Artificial soils with contrasting texture, but identical mineral composition, were used to mimic subsoil conditions, where mineral surfaces free of OM come into contact with percolating DOM. After the incubation, we assessed the solution exchange, OM covers on minerals, microbial community and OC turnover, and aggregate formation and stability. Results: A higher sand content caused a lower porosity, accompanied by a lower moisture content. In contrast, the OC retention (21% of the OC input), microbial activity, and community size were unaffected by soil texture. The OM covered 10% of the mineral surfaces within an otherwise OC‐free mineral matrix. The formation of large, water‐stable aggregates occurred in all soils, but was pronounced in the clay‐rich soils (58% mass contribution), which also supported a higher mechanical stability of the aggregates. Conclusions: The initial retention and microbial mineralization of DOM are decoupled from pore sizes and soil solution exchange but are driven by the mineral composition and OC input. The biochemical processing of the percolating DOM can induce large aggregates. Here, the presence of fine mineral particles enhances the formation and mechanical stability of the aggregates, irrespective of their surface charge or sorptive properties. [ABSTRACT FROM AUTHOR]

Abstract Background The rapid expansion of research on Brain-Computer Interfaces (BCIs) is not only due to the promising solutions offered for persons with physical impairments. There is also a heightened need for understanding BCIs due to the challenges regarding ethics presented by new technology, especially in its impact on the relationship between man and machine. Here we endeavor to present a scoping review of current studies in the field to gain insight into the complexity of BCI use. By examining studies related to BCIs that employ social research methods, we seek to demonstrate the multitude of approaches and concerns from various angles in considering the social and human impact of BCI technology. Methods For this scoping review of research on BCIs’ social and ethical implications, we systematically analyzed six databases, encompassing the fields of medicine, psychology, and the social sciences, in order to identify empirical studies on BCIs. The search yielded 73 publications that employ quantitative, qualitative, or mixed methods. Results Of the 73 publications, 71 studies address the user perspective. Some studies extend to consideration of other BCI stakeholders such as medical technology experts, caregivers, or health care professionals. The majority of the studies employ quantitative methods. Recurring themes across the studies examined were general user opinion towards BCI, central technical or social issues reported, requests/demands made by users of the technology, the potential/future of BCIs, and ethical aspects of BCIs. Conclusions Our findings indicate that while technical aspects of BCIs such as usability or feasibility are being studied extensively, comparatively little in-depth research has been done on the self-image and self-experience of the BCI user. In general there is also a lack of focus or examination of the caregiver’s perspective.

Glioblastoma (GBM) is a devastating disease and the most common primary brain malignancy of adults with a median survival barely exceeding one year. Recent findings suggest that the antipsychotic drug pimozide triggers an autophagy-dependent, lysosomal type of cell death in GBM cells with possible implications for GBM therapy. One oncoprotein that is often overactivated in these tumors and associated with a particularly dismal prognosis is Signal Transducer and Activator of Transcription 3 (STAT3). Here, we used isogenic human and murine GBM knockout cell lines, advanced fluorescence microscopy, transcriptomic analysis and FACS-based assessment of cell viability to show that STAT3 has an underappreciated, context-dependent role in drug-induced cell death. Specifically, we demonstrate that depletion of STAT3 significantly enhances cell survival after treatment with Pimozide, suggesting that STAT3 confers a particular vulnerability to GBM. Furthermore, we show that active STAT3 has no major influence on the early steps of the autophagy pathway, but exacerbates drug-induced lysosomal membrane permeabilization (LMP) and release of cathepsins into the cytosol. Collectively, our findings support the concept of exploiting the pro-death functions of autophagy and LMP for GBM therapy and to further determine whether STAT3 can be employed as a treatment predictor for highly apoptosis-resistant, but autophagy-proficient cancers.