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Human cytochrome P450 (P450) 27A1 catalyzes the hydroxylation of cholesterol and vitamin D derivatives. P450 27A1 is localized in the mitochondria and is reduced by its redox partner protein adrenodoxin twice for each catalytic cycle. The reliance on adrenodoxin is conserved across all human mitochondrial P450 enzymes. This study examines the adrenodoxin interaction with P450 27A1 and draws comparisons with studies of other P450 enzymes to determine if differences exist. The P450-adrenodoxin complex structure was examined by chemical crosslinking and analyzed by mass spectrometry. The effect of adrenodoxin concentration on P450 27A1 function was assessed by studying effects on steady state enzyme kinetics parameters and equilibrium substrate binding. The results suggest that adrenodoxin binds to P450 27A1 at a proximal site like other P450 enzymes but differs in the specific residues involved. Furthermore, the presence of adrenodoxin and/or substrate decreases the number of interprotein and intraprotein crosslinks observed, indicating that these components change the conformation of the P450 enzyme. Increased adrenodoxin concentration causes the P450 and vitamin D3 kcat value to increase, the kcat/Km value to decrease, and the substrate Kd to remain constant. These results suggest adrenodoxin alters enzyme efficiency beyond electron transfer without affecting substrate loading. The adrenodoxin effects on P450 27A1 kinetics and equilibrium constants differ from those of other human mitochondrial P450 enzymes. In total, these structural and functional studies suggest that while the general adrenodoxin binding site and function is conserved across P450 enzymes, the details and additional effects of this interaction vary. 

ABSTRACT The fungusConoideocrella luteorostratais a recently discovered pathogen of invasive elongate hemlock scale insects (EHS;Fiorinia externa) in Christmas tree farms in the eastern U.S. Here, we report a scaffold-level genome and assembly along with an initial survey of biosynthetic gene clusters for strain ARSEF 14590 from EHS. 

ABSTRACT The fungal genusNeonectriacontains many phytopathogenic species currently impacting forests and fruit trees worldwide. Despite their importance, a majority ofNeonectriaspp. lack sufficient genomic resources to resolve suspected cryptic species. Here, we report draft genomes and assemblies forNeonectria magnoliaeNRRL 64651 andNeonectria puniceaNRRL 64653. 

ABSTRACT Disturbance events can impact ecological community dynamics. Understanding how communities respond to disturbances and how those responses can vary is a challenge in microbial ecology. In this study, we grew a previously enriched specialized microbial community on either cellulose or glucose as a sole carbon source and subjected them to one of five different disturbance regimes of varying frequencies ranging from low to high. Using 16S rRNA gene amplicon sequencing, we show that the community structure is largely driven by substrate, but disturbance frequency affects community composition and successional dynamics. When grown on cellulose, bacteria in the generaCellvibrio,Lacunisphaera, andAsticcacaulisare the most abundant microbes. However,Lacunisphaerais only abundant in the lower disturbance frequency treatments, whileAsticcacaulisis more abundant in the highest disturbance frequency treatment. When grown on glucose, the most abundant microbes are twoPseudomonassequence variants and aCohnellasequence variant that is only abundant in the highest disturbance frequency treatment. Communities grown on cellulose exhibited a greater range of diversity (1.95–7.33 Hill 1 diversity) that peaks at the intermediate disturbance frequency treatment or one disturbance every 3 days. Communities grown on glucose, however, ranged from 1.63 to 5.19 Hill 1 diversity with peak diversity at the greatest disturbance frequency treatment. These results demonstrate that the dynamics of a microbial community can vary depending on substrate and the disturbance frequency and may potentially explain the variety of diversity–disturbance relationships observed in microbial systems. IMPORTANCEA generalizable diversity–disturbance relationship (DDR) of microbial communities remains a contentious topic. Various microbial systems have different DDRs. Rather than finding support or refuting specific DDRs, we investigated the underlying factors that lead to different DDRs. In this study, we measured a cellulose-enriched microbial community’s response to a range of disturbance frequencies from high to low, across two different substrates: cellulose and glucose. We demonstrate that the community displays a unimodal DDR when grown on cellulose and a monotonically increasing DDR when grown on glucose. Our findings suggest that the same community can display different DDRs. These results suggest that the range of DDRs we observe across different microbial systems may be due to the nutritional resources microbial communities can access and the interactions between bacteria and their environment. 

Abstract Self‐stabilized, heterometallic pair‐sites can enable fine‐tuning of catalytic functionality while also mitigating dynamic structural changes that degrade catalytic performance. This study demonstrates the development and characterization of trimetallic Pt_xCr_xAg_1‐2x(x≤ 0.1) alloys with active Pt–Cr pair‐ensembles for non‐oxidative ethanol dehydrogenation, leveraging predictions that favorable bonding stabilizes Pt–Cr pairs diluted in Ag. Operando X‐ray absorption spectroscopy confirms the preferential formation and stability of Pt–Cr pairings dispersed throughout the Ag matrix, and ambient‐pressure X‐ray photoelectron spectroscopy shows that Pt–Cr sites have significant activity for ethanol dehydrogenation, while suppressing reaction processes that deactivate binary Pt–Ag and Cr–Ag alloys. This work demonstrates that stabilizing heterometallic pair sites within trimetallic alloys provides a new avenue for designing catalysts with discrete active sites that are durable and highly selective. 

We used the 138Baðd; αÞ reaction to carry out an in-depth study of states in 136Cs, up to around 2.5 MeV. In this Letter, we place emphasis on hitherto unobserved states below the first 1þ level, which are important in the context of solar neutrino and fermionic dark matter (FDM) detection in large-scale xenon-based experiments. We identify for the first time candidate metastable states in 136Cs, which would allow a realtime detection of solar neutrino and FDM events in xenon detectors, with high background suppression. Our results are also compared with shell-model calculations performed with three Hamiltonians that were previously used to evaluate the nuclear matrix element (NME) for 136Xe neutrinoless double beta decay.We find that one of these Hamiltonians, which also systematically underestimates the NME compared with the others, dramatically fails to describe the observed low-energy 136Cs spectrum, while the other two show reasonably good agreement. 

Abstract We present analysis using a citizen science campaign to improve the cosmological measures from the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the Hubble expansion rate,H(z), and angular diameter distance,D_A(z), atz= 2.4, each to percent-level accuracy. This accuracy is determined primarily from the total number of detected Lyαemitters (LAEs), the false positive rate due to noise, and the contamination due to [Oii] emitting galaxies. This paper presents the citizen science project, Dark Energy Explorers (https://www.zooniverse.org/projects/erinmc/dark-energy-explorers), with the goal of increasing the number of LAEs and decreasing the number of false positives due to noise and the [Oii] galaxies. Initial analysis shows that citizen science is an efficient and effective tool for classification most accurately done by the human eye, especially in combination with unsupervised machine learning. Three aspects from the citizen science campaign that have the most impact are (1) identifying individual problems with detections, (2) providing a clean sample with 100% visual identification above a signal-to-noise cut, and (3) providing labels for machine-learning efforts. Since the end of 2022, Dark Energy Explorers has collected over three and a half million classifications by 11,000 volunteers in over 85 different countries around the world. By incorporating the results of the Dark Energy Explorers, we expect to improve the accuracy on theD_A(z) andH(z) parameters atz= 2.″4 by 10%–30%. While the primary goal is to improve on HETDEX, Dark Energy Explorers has already proven to be a uniquely powerful tool for science advancement and increasing accessibility to science worldwide. 

Abstract The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) is an untargeted spectroscopic survey that aims to measure the expansion rate of the universe at z ∼ 2.4 to 1% precision for both H ( z ) and D A ( z ). HETDEX is in the process of mapping in excess of one million Ly α emitting (LAE) galaxies and a similar number of lower- z galaxies as a tracer of the large-scale structure. The success of the measurement is predicated on the post-observation separation of galaxies with Ly α emission from the lower- z interloping galaxies, primarily [O ii ], with low contamination and high recovery rates. The Emission Line eXplorer (ELiXer) is the principal classification tool for HETDEX, providing a tunable balance between contamination and completeness as dictated by science needs. By combining multiple selection criteria, ELiXer improves upon the 20 Å rest-frame equivalent width cut commonly used to distinguish LAEs from lower- z [O ii ] emitting galaxies. Despite a spectral resolving power, R ∼ 800, that cannot resolve the [O ii ] doublet, we demonstrate the ability to distinguish LAEs from foreground galaxies with 98.1% accuracy. We estimate a contamination rate of Ly α by [O ii ] of 1.2% and a Ly α recovery rate of 99.1% using the default ELiXer configuration. These rates meet the HETDEX science requirements.