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Summary Unlike most ectomycorrhizal (EM) fungi,Cenococcum geophilumis a prolific producer of sclerotia, which represent a large and persistent, yet rarely quantified pool of EM fungal biomass and carbon in soils. How biomass of these asexual propagules is impacted by global change factors, such as anthropogenic nitrogen (N) deposition, remains unquantified.This study examined the effects of long‐term experimental N fertilization on the standing biomass, abundance, and size ofC. geophilumsclerotia in an oak (Quercusspp.) savanna ecosystem at Cedar Creek Ecosystem Science Reserve in Minnesota, USA.Standing sclerotia biomass in the control treatment averaged 192 g m⁻²(95% CI = 136–267 g m⁻²) and declined sharply under N enrichment, by 44% (95% CI = −53–79%) and 66% (95% CI = 39–82%) in the low N (5.4 g N m⁻² yr⁻¹) and high N (17 g N m⁻² yr⁻¹) treatments, respectively. Sclerotia abundance also declined under both fertilization levels by 58% (95% CI: 8–81%) and 62% (95% CI: 12–84%), while sclerotia diameter was significantly reduced only under high N.Given their high carbon content, melanization, and long persistence, the observed declines inC. geophilumsclerotia (c.84–127 g m⁻²) represent substantial losses from belowground carbon (C) pools. These findings indicate that chronic N deposition suppresses the formation of a functionally important and recalcitrant fungal structure, likely impacting soil C storage and mycorrhizal functional diversity. 

Abstract The exceptionally low-energy²²⁹Th nuclear isomeric state is expected to provide several new and powerful applications^1,2, including the construction of a robust and portable solid-state nuclear clock³, perhaps contributing to a redefinition of the second⁴, exploration of nuclear superradiance^5,6and tests of fundamental physics^7–10. Further, analogous to the capabilities of traditional Mössbauer spectroscopy, the sensitivity of the nucleus to its environment can be used to realize laser Mössbauer spectroscopy and, with it, new types of strain and temperature sensors^3,11and a new probe of the solid-state environment^12,13, all with excellent sensitivity. However, current models for examining the nuclear transition in a solid require the use of a high-bandgap, vacuum ultraviolet (VUV) transmissive host, severely limiting the applicability of these techniques. Here we report the first, to the authors’ knowledge, demonstration of laser-induced conversion electron Mössbauer spectroscopy (CEMS) of the²²⁹Th isomer in a thin ThO₂sample whose bandgap (approximately 6 eV) is considerably smaller than the nuclear isomeric state energy (8.4 eV). Unlike fluorescence spectroscopy of the²²⁹Th isomeric transition, this technique is compatible with materials whose bandgap is less than the nuclear transition energy, opening a wider class of systems to study and the potential of a conversion-electron-based nuclear clock. 

The concept that proteins are selected to fold into a well-defined native state has been effectively addressed within the framework of energy landscapes, underpinning the recent successes of structure prediction tools like AlphaFold. The amyloid fold, however, does not represent a unique minimum for a given single sequence. While the cross-βhydrogen-bonding pattern is common to all amyloids, other aspects of amyloid fiber structures are sensitive not only to the sequence of the aggregating peptides but also to the experimental conditions. This polymorphic nature of amyloid structures challenges structure predictions. In this paper, we use AI to explore the landscape of possible amyloid protofilament structures composed of a single stack of peptides aligned in a parallel, in-register manner. This perspective enables a practical method for predicting protofilament structures of arbitrary sequences: RibbonFold. RibbonFold is adapted from AlphaFold2, incorporating parallel in-register constraints within AlphaFold2’s template module, along with an appropriate polymorphism loss function to address the structural diversity of folds. RibbonFold outperforms AlphaFold2/3 on independent test sets, achieving a mean TM-score of 0.5. RibbonFold proves well-suited to study the polymorphic landscapes of widely studied sequences with documented polymorphisms. The resulting landscapes capture these observed polymorphisms effectively. We show that while well-known amyloid-forming sequences exhibit a limited number of plausible polymorphs on their “solubility” landscape, randomly shuffled sequences with the same composition appear to be negatively selected in terms of their relative solubility. RibbonFold is a valuable framework for structurally characterizing amyloid polymorphism landscapes. 

Abstract The Southern Ocean (south of 30°S) contributes significantly to global ocean carbon uptake through the solubility, physical and biological pumps. Many studies have estimated carbon export to the deep ocean, but very few have attempted a basin‐scale perspective, or accounted for the sea‐ice zone (SIZ). In this study, we use an extensive array of BGC‐Argo floats to improve previous estimates of carbon export across basins and frontal zones, specifically including the SIZ. Using a new method involving changes in particulate organic carbon and dissolved oxygen along the mesopelagic layer, we find that the total Southern Ocean carbon export from 2014 to 2022 is 2.69 ± 1.23 PgC y⁻¹. The polar Antarctic zone contributes the most (41%) with 1.09 ± 0.46 PgC y⁻¹. Conversely, the SIZ contributes the least (8%) with 0.21 ± 0.09 PgC y⁻¹and displays a strong shallow respiration in the upper 200 m. However, the SIZ contribution can increase up to 14% depending on the depth range investigated. We also consider vertical turbulent fluxes, which can be neglected at depth but are important near the surface. Our work provides a complementary approach to previous studies and is relevant for work that focuses on evaluating the biogeochemical impacts of changes in Antarctic sea‐ice extent. Refining estimates of carbon export and understanding its drivers ultimately impacts our comprehension of climate variability at the global ocean scale. 

Data include soil and litter measurements for moisture, pH, and carbon-to-nitrogen ratio. Samples were collected from 8 different ecoregions, as determined by NEON, at various NEON/LTER and/or other experimental sites. Soil cores and litter samples were taken in the spring and fall of 2022. 

Chromatin is partially structured through the effects of biological motors. “Swimming motors” such as RNA polymerases and chromatin remodelers are thought to act differentially on the active parts of the genome and the stored inactive part. By systematically expanding the many-body master equation for chromosomes driven by swimming motors, we show that this nonuniform aspect of motorization leads to heterogeneously folded conformations, thereby contributing to chromosome compartmentalization.