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Subterranean arthropods are important components of soils and contribute essential food-web functions and other ecosystem services, however, their diversity and community composition has scarcely been assessed. Subterranean pitfall traps are a commonly used method for sampling soil habitats in Europe but have never been widely implemented in the Americas. We used subterranean pitfall traps to sample previously unsurveyed arthropod communities in southwestern Virginia, U.S. Traps were placed in shallow subterranean habitats (SSHs), underground habitats close to the surface where light does not penetrate, and more specifically at the interface between the soil and underlying “milieu souterrain superficiel”—a microhabitat consisting of the air-filled interstitial spaces between rocks (abbreviated MSS). In total, 2,260 arthropod specimens were collected constituting 345 morphospecies from 8 classes, 33 orders, and 94 families. A region of the mitochondrial cytochromecoxidase subunit I (COI) gene was amplified and sequenced, and objective sequence clustering of 3% was used to establish molecular operational taxonomic units (mOTUs) to infer observed species richness. In all, 272 COI barcodes representing 256 mOTUs were documented for rare soil-dwelling arthropod taxa and are published to build a molecular library for future research in this system. This work is the first taxonomically extensive survey of North American soil-dwelling arthropods greater than 10 cm below the soil surface. 

Abstract Microbial aerobic methane oxidation is an important sink for aquatic methane worldwide. Despite its importance to global methane fluxes, few aerobic methane oxidation rates have been obtained in freshwater or marine environments without imposing changes to the microbial community through use of ex situ methods. A novel in situ incubation method for continuous time‐series measurements was used in Jordan Lake, North Carolina, during 2020–2021, to determine reaction kinetics for aerobic methane oxidation rates across a wide range of naturally varying methane (55–1833 nM) and dissolved oxygen (DO; 28–366 μM) concentrations and temperatures (17–30°C). Methane oxidation began immediately at the start of each of 21 incubations and methane oxidation rates were 1^storder with respect to methane. The data density allowed for accurate calculation of 1^st‐order rate constants,k, that ranged from 0.018 to 0.462 h⁻¹(R² > 0.967). Addition of ammonium (20–45 μM) to natural concentrations ranging from 0.057 to 2.4 μM did not change aerobic methane oxidation rate kinetics, suggesting that the natural population of aerobic methane oxidizers in this eutrophic lake was not nitrogen limited. Values ofkinversely correlated most strongly with initial DO concentrations (R² = 0.82) rather than temperature. Values forkincreased with Julian day throughout our sampling period, suggesting seasonal influences on methane oxidation via responses to geochemical changes or shifts in microbial community abundance and composition. These experiments demonstrate a high variability in the enzymatic capacity for 1^st‐order methane oxidation rates in this eutrophic lake that is tightly and inversely coupled to oxygen concentrations. Measurements of in situ aerobic methane oxidation rate constants allow for the direct quantification and modeling of the microbial community's capacity for methane oxidation over a wide range of natural methane concentrations. 

Abstract In this study, the binding of multimodal chromatographic ligands to the IgG1 F_Cdomain were studied using nuclear magnetic resonance and molecular dynamics simulations. Nuclear magnetic resonance experiments carried out with chromatographic ligands and a perdeuterated¹⁵N‐labeled F_Cdomain indicated that while single‐mode ion exchange ligands interacted very weakly throughout the F_Csurface, multimodal ligands containing negatively charged and aromatic moieties interacted with specific clusters of residues with relatively high affinity, forming distinct binding regions on the F_C. The multimodal ligand‐binding sites on the F_Cwere concentrated in the hinge region and near the interface of the C_H2 and C_H3 domains. Furthermore, the multimodal binding sites were primarily composed of positively charged, polar, and aliphatic residues in these regions, with histidine residues exhibiting some of the strongest binding affinities with the multimodal ligand. Interestingly, comparison of protein surface property data with ligand interaction sites indicated that the patch analysis on F_Ccorroborated molecular‐level binding information obtained from the nuclear magnetic resonance experiments. Finally, molecular dynamics simulation results were shown to be qualitatively consistent with the nuclear magnetic resonance results and to provide further insights into the binding mechanisms. An important contribution to multimodal ligand‐F_Cbinding in these preferred regions was shown to be electrostatic interactions and π–π stacking of surface‐exposed histidines with the ligands. This combined biophysical and simulation approach has provided a deeper molecular‐level understanding of multimodal ligand–F_Cinteractions and sets the stage for future analyses of even more complex biotherapeutics.