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Does the quality of pain relief after major surgery influence the risk of postoperative complications? A prospective observational study

Objectives Effective postoperative acute pain management continues to be a challenge. It remains uncertain whether poorly controlled postoperative pain influences the risk of postoperative complications. Therefore, we aimed to investigate whether indicators of poor pain control increase the likelihood of cardiac, pulmonary, infectious, thromboembolic, and surgical complications, as well as of prolonged use of analgesics. Methods This prospective observational study combines treatment data from the German net-ra registry and claims data from the second-largest public health insurer BARMER (Mar 1, 2021-Mar 31, 2022). A total of 539 adult inpatients who had undergone major surgery and received planned postoperative care from acute pain services were analyzed. Adjusted binary logistic regression models were fitted to compare patients with inadequately (NRS > 3) and adequately controlled pain, with (NRS > 6) and without pain peaks, and with slow or rapid pain recovery (median split of the time to sustained adequate pain control NRS ≤ 3) with regard to the risk of postoperative complications and prolonged use of analgesics as a proxy of chronic postoperative pain. Results Patients with inadequately controlled pain within the first three postoperative days had more than twice the risk of complications (adjOR 2.56; 95% CI 1.43–4.80, p = 0.002), as did patients with slow pain recovery (adjOR 2.21; 95% CI 1.35–3.64, p = 0.002). No significant effect could be observed for pain peaks (adjOR 1.27; 95% CI 0.64 to 2.42, P = 0.478). Inadequate pain control did not significantly affect prolonged use of analgesics (adjOR 1.87; 95% CI 0.98–3.72, p = 0.064), nor did pain peaks or recovery speed show any influence. Discussion We observed a clear link between postoperative quality of pain control and complications, along with a trend towards prolonged use of analgesics. Therefore, postoperative acute pain should be regularly assessed and minimized until resolved. Further research into patient- and procedure-specific factors is essential to reduce adverse pain-related outcomes.

Spatiotemporal mapping of alloy mesostructure dynamics via multimodal coherent X-ray diffraction imaging

Understanding mesoscale structural dynamics of precipitation-strengthened alloys is essential for optimizing the mechanical performances of these alloys. Herein, we establish a multimodal coherent X-ray diffraction imaging framework for spatiotemporal mapping of mesoscale structural dynamics in precipitation-strengthened alloys. As a demonstrative application, we visualized the structural evolution in Mg 97 Zn 1 Gd 2 during isothermal annealing at 700 K, revealing real-time dynamics of nucleation, growth, and coarsening. Ptychographic reconstruction enabled imaging of microstructural transformations across a wide field of view (~100 μm 2 ) with temporal resolution spanning several hours. We observed decomposition of (Mg, Zn) 3 Gd and concurrent precipitation and coarsening of long-period stacking ordered phases. To resolve local dynamics at finer spatiotemporal scales, we combined dynamic coherent diffraction imaging with X-ray photon correlation spectroscopy, targeting selected regions (~10 μm 2 ) with time resolution down to tens of seconds. This approach revealed the rapid formation of nanoscale precipitates within 10 s after heating, followed by coarsening over several hundred seconds. Additionally, we applied optical flow analysis—a computational method to track motion patterns—to visualize and quantify the nucleation, growth, and coarsening kinetics. The abovementioned findings demonstrate the capability of in situ coherent X-ray techniques to acquire the real-time evolutions of mesoscale structures in complex materials. Our methodology offers a robust framework for investigating dynamic phenomena in diverse material systems, including metals, polymers, and functional nanomaterials, under realistic thermal or mechanical conditions.

Effects of behavior change techniques in interventions promoting condom use among youth in the Global North

Background Declines in condom use among the general young population highlight the need for effective interventions to prevent sexually transmitted infections and unwanted pregnancies. With this study, we aim to examine the relationship between Behavior Change Techniques (BCTs, the active components of interventions) and the effects of condom interventions among youth. We quantify the number of BCTs used in the interventions, assess their alignment with underlying behavioral theory, and evaluate coverage of specified Mechanisms of Action (MoA, underlying process through which behavior may be influenced) within the behavioral theory. Methods Face-to-face theory-based interventions aiming to promote condom use among youth were identified in a previous systematic review. Interventions were analyzed using the BCT Taxonomy v.1.0., alignment with theory was determined using the Theories and Techniques tool. Wilcoxon rank-sum tests assessed BCT effectiveness. Spearman’s rank correlation coefficient determined associations between intervention effects and the total number of BCTs, the proportion of BCTs aligned with MoAs, and the proportion of MoA covered by BCTs. Results In 21 interventions we identified a median of 3 BCTs (IQR = 1–5) per intervention. BCTs were poorly reported. No grouping of BCTs was associated with more intervention effects on increasing condom use. Neither the proportion of BCTs aligned with the MoAs of the underlying theory in the intervention (median = 85.7%, IQR = 50.0–100%, Spearman’s ρ = −0.09) nor the proportion of MoAs of the underlying theory covered by at least one BCT in the intervention (median = 44.4%, IQR = 25.0–50.0%, Spearman’s ρ = 0.27) were correlated with intervention effects. Conclusions This study provides initial insights into the use of BCTs and the application of behavioral theory in theory-based condom promotion interventions targeting the general young population. No associations between the use of BCTs and the intervention effects on condom use were found. Robust conclusions regarding the utilization of BCTs, their alignment with theory, and their effects can only be reached when future research consistently and comprehensively reports the use of BCTs.

Designers join scientists to make living architecture a reality

Mitochondrial polymorphism of sea beet (Beta vulgaris ssp. maritima), a species with cytoplasmic male sterility

Cytoplasmic male sterility (CMS), a form of mitochondrion-induced male sterility, is a valuable trait for hybrid breeding in crop production. However, CMS is not universally present across all crop species, prompting ongoing efforts to identify CMS sources within genetic resources. The discovery of CMS could be facilitated by the development of predictive indices indicating the presence of CMS-associated mitochondria. One theory has proposed that populations containing CMS-expressing plants exhibit elevated mitochondrial polymorphism. Sea beet, a species known to harbor CMS, provides a suitable system for testing this prediction. We first conducted network analysis by using mitochondrial single nucleotide polymorphism sites extracted from publicly available nucleotide sequence data. The resulting network, constructed from 270 sea beet sequences, was complex yet characterized by several star-like clusters. Haplotypes from Mediterranean region were dispersed across the network, while those from Atlantic coast tended to cluster, supporting the hypothesis that sea beet originated in the Mediterranean area and later migrated to the Atlantic coast. We then analyzed four mitochondrial minisatellites—variable number of tandem repeat loci— across 973 plants of 172 sea beet accessions. Combination of alleles at these four loci defined 29 distinct mitotypes. Analysis of mitotype distribution revealed similarly high mitochondrial polymorphism (~0.87) in both the Mediterranean and the Atlantic regions, despite their genic differentiation. Most subregions within these areas contained 8–15 mitotypes; however, Denmark was a notable exception, with only a single mitotype detected among 139 plants from 11 accessions. This mitochondrial monomorphism contrasts with the diversity observed in neighboring Atlantic subregions, indicating that Danish sea beet constitutes an exceptional population. Notably, the Danish mitotype was not associated with any CMS, suggesting that the population may be devoid of CMS mitochondria— a condition in which the proposed mechanism for increased mitochondrial polymorphism would not be operative.

Kupffer cells are essential for platelet-mediated thrombopoietin generation in the liver

Thrombopoietin (TPO), predominantly produced by the liver, is the key regulator for platelet production and the hematopoietic stem cell niche. Our earlier report demonstrated that platelet GPIbα is required for hepatocellular TPO generation, which is the major resource of TPO in the blood circulation. However, how hepatocytes physically contact circulating sinusoidal platelets across the liver endothelium for this process is unknown. Kupffer cells reside in contact with both sinusoidal blood and underlying hepatocytes, and mediate senescent platelet clearance, but their role in TPO regulation has never been explored. Here, we found Kupffer cell depletion via either clodronate liposomes or specific transgenic models abrogated circulating TPO. Kupffer cell depletion also prevented TPO level increase in GPIbα-deficient mice following wild-type (GPIbα + ) platelet transfusion, signifying an interdependent mechanism for TPO regulation. Mice treated with arsenite had significantly decreased liver endothelial fenestrations and hepatocyte sinusoidal protrusions as well as TPO levels. This effect was exacerbated by Kupffer cell depletion, and Kupffer cells were identified to enhance liver endothelial fenestrations. Electron microscopy and immunofluorescence analysis of the liver revealed platelets arrested on Kupffer cell surface were in contact with hepatocyte protrusions. Thus, we elucidated that Kupffer cells promote endothelial fenestrae and hepatocyte protrusions, accumulate circulating platelets, and facilitate cellular interactions between hepatocytes and platelets, which drive TPO generation. This connection between platelet clearance and thrombopoiesis should have broad implications for hematology and pathologies such as Bernard–Soulier syndrome, thrombocytopenias, as well as liver diseases.

Light-PTNet: A lightweight parallel temporal network for smartphone-based human motion classification

The increased popularity of smartphone-based human activity recognition (HAR) in recent decades has been driven by its low computational requirements and user privacy protection. Yet, developing a reliable smartphone-based HAR still presents several challenges. For example, handcrafted feature-based approaches highly depend on laborious feature engineering/selection techniques that require human intervention. Implementing conventional Convolutional Neural Networks may result in unsatisfactory performance in time series classification as they cannot effectively extract time-dependent features. Although recurrent models excel at extracting temporal information, they require extensive computational resources to attain high performance, limiting their practicality for real-time applications. Thus, we propose a lightweight smartphone-based HAR architecture called Lightweight Parallel Temporal Network (Light-PTNet) for reliable classification. Light-PTNet comprises parallelly organised Light Spatial-Temporal Heads (LSTC Heads) that capture underlying patterns at various scales of the inertial signals. These heads utilise dilations and residual connections to preserve longer-term dependencies without increasing the model parameters. This work assesses the proposed Light-PTNet’s performance on open-access HAR datasets: UCI HAR, WISDM V1, and UniMiB SHAR, following a user-independent protocol. The results reveal that our proposed Light-PTNet achieves 98.03% accuracy on UCI HAR, 81.58% on UniMiB SHAR and 97.02% on WISDM V1 with fewer model parameters (lower than 0.1 million parameters).

Correction for Mitani et al., Microscopic and structural observations of actin filament capping and severing by cytochalasin D

Dehydration does not drive host behavioural manipulation by hairworms

Nematomorphs are parasitic worms of arthropods, which complete their life cycle via behavioural manipulation of their host so that they can enter water to find a mate. Although this behaviour is readily observed, the underlying mechanism is largely unknown; previously proposed hypotheses include an attraction to polarised light, increased erratic behaviour and dehydration-driven behaviour. Here, we investigated the ‘Dehydration Hypothesis’, which posits that nematomorphs either induce dehydration or mimic dehydration through biosynthetic changes to stimulate host water-seeking behaviour. House crickets, Acheta domesticus, were experimentally deprived of water and their behaviour compared to crickets infected with the nematomorph Paragordius varius. Both infected and dehydrated crickets were more likely to interact with water than uninfected, hydrated crickets. However, dehydrated crickets preferred to submerge their heads in the water compared to infected crickets which preferred to fully enter the water. Quantitative mass spectrometry of cricket haemolymph identified unique proteomic signatures of infection (27 differentially abundant proteins, infected cf. control) and dehydration (17 differentially abundant proteins, dehydrated cf. control). Our results indicate that dehydration is not a strong driving mechanism for behavioural manipulation by nematomorphs, but nevertheless infected and dehydrated share the increased tendency of dehydrated crickets to interact with water. Our data also provide new insights into the proteomic response during nematomorph infection. Notably, we observed a decrease in the cricket egg yolk protein vitellogenin and the carbohydrate digestion enzyme α-amylase, and an increase in abundance of the immune related hemocyanin protein family.

An open-source photobleacher for fluorescence imaging of large pigment-rich tissues

Fluorescence imaging enables visualization of the specific molecules of interest with high contrast, and the use of multiple fluorophores in a single tissue sample allows visualization of complex relationships between biological molecules, cell types, and anatomy. The utility of fluorescence imaging in human tissue has been limited by endogenous pigments that can block the light path or emit an autofluorescence, thereby interfering with the specific imaging of target molecules. Although photobleachers have been developed to quench endogenous pigments, the lack of customizability limits their utility for a broad range of applications. Here, we present a high luminous-intensity photobleacher that is based on rigorous simulations of illumination patterns, along with the framework to maximize bleaching efficiency. This open-source project is designed to help scientists customize and scale the device according to their research goals. The photobleacher is applicable to both thin tissue slices and large-volume cleared tissue samples to enable serial three-dimensional imaging of postmortem human brain using multiplexed antibody or oligonucleotide probes.

Can random walking on a Hi-C contact matrix lead to data quality improvement? An assessment

Hi-C and single cell Hi-C (scHi-C) data are now routinely generated for studying an array of biological questions of interest, including whole genome chromatin organization to gain a better understanding of the chromosome three-dimensional hierarchical structure: compartments, Topologically Associated Domains (TADs), and long-range interactions. Due to concerns about data quality, especially for scHi-C because of its sparsity, data quality improvement is seen as a necessary step before performing analyses to answer biological questions. As such, methods have been developed accordingly, among them is a set of methods that are “random walk”- based, including random walk with a limited number of steps (RWS) and random walk with restart (RWR). Nevertheless, there is little justification for the use of such methods, nor quantification of their performance success. Taking correct identification of TADs as the end point, in this paper, we describe the characteristics of random-walk-based approaches and carry out empirical investigation for identifying TADs before and after random walks. Due to the lack of practical guidelines for choosing tuning parameters necessary for performing random walks, it is difficult to know how many steps of random walk for RWS or how small a restart probability for RWR should one choose to achieve good performance. Even in the unrealistic scenario when one has the hindsight to use the optimal parameter values, little improvement in downstream TAD analyses by first performing random walk was observed. This conclusion was based on extensive analytical analyses, simulation study, and real data applications. Therefore, the current study provides a cautionary note to researchers who may consider using random-walk-based approaches prior to downstream analyses.

Intercellular propagation of RIPK1/RIPK3 amyloid fibrils

The canonical necrosome formed by receptor-interacting protein kinase 1 (RIPK1) and RIPK3 is a functional amyloid fibril structure critical to intracellularly drive necroptosis. Since necroptosis leads to the release of intracellular content, the fate of RIPK1/RIPK3 fibrils after necroptotic cell death has not been investigated. Here, we tracked RIPK1 and RIPK3 coassemblies and found that these fibrillar aggregates could be released into the culture medium after the membrane rupture in necroptotic cells. Interestingly, these RIPK1/RIPK3 fibrils were capable of infiltrating recipient cells and acting as seeds for the nucleation and formation of the endogenous necrosome. Cryo electron microscopy structural analysis unveiled a distinctive S-shaped conformation common to RHIM fibrils of RIPK1 and RIPK3, which can facilitate the cross-seeding of RIPK3 by RIPK1 or RIPK1/RIPK3 fibrils. Our findings suggest the ability of functional RIPK1/RIPK3 amyloid fibrils in intercellular spreading to induce protein conformation change in recipient cells and provide structural insights into the mechanism of RIPK1 and RIPK3 cross-templating to drive necroptosis.

Validity of four low-cost smartwatches in estimating energy expenditure during cycling in Chinese untrained women

Wrist-worn activity monitors, such as smartwatches, are frequently used to monitor energy expenditure (EE) of physical activity, but there is a high degree of heterogeneity in their accuracy. The purpose of this study was to evaluate the validity of four affordable, low-price smartwatches, including HONOR Band 7 (HNB7), HUAWEI Band 8 (HWB8), XIAOMI Smart Band 8 (XMB8), and KEEP Smart Band B4 Lite (KPB4L), for estimating EE during ergometer cycling in untrained Chinese women. Twenty Chinese women who exercised ≤3 times per week simultaneously wore two smartwatches, randomly assigned to each wrist, during cycling at 30W, 40W, 50W and 60W on the ergometer. As the golden standard, indirect calorimetry (CORTEX METAMAX 3B, MM3B) was used to evaluate EE at the same time. For all loads, EE values were significantly overestimated by XMB8 and KPB4L, compared to the golden standard (all p < 0.001), but not by HNB7 and HWB8. The mean absolute percentage error (MAPE) was 49.5–57.4% for the KPB4L, 30.5–41.0% for the XMB8, 12.5–18.6% for the HWB8, and 15.0–23.0% for the HNB7, respectively. A lower MAPE value indicates that smartwatch estimates are closer to the golden standard. Bland–Altman plots indicated a trend of increasing positive bias as EE increased across all devices, with the XMB8 and KPB4L showing this pattern most clearly. The results clearly show that although HNB7 and HWB8 demonstrated moderate accuracy, there were significant differences in EE estimation accuracy across the tested devices. These findings suggest caution in using low-price smartwatches for energy balance management in untrained female populations. However, the findings of this study are subject to limitations, such as a small and homogeneous sample size, and the occasional missing of data across multiple load levels. Future studies should increase the sample size and include more diverse participants to validate these findings.

Methionine synthesis and glycine betaine demethylation are intricately intertwined in cosmopolitan marine bacteria

Across all domains of life, cobalamin-dependent methyltransferases have diversified to perform a range of crucial functions, such as methionine synthesis and the demethylation of various reduced nitrogen and sulfur compounds. These large modular enzymes typically possess three substrate-binding domains, two binding either the methyl donor or methyl acceptor, as well as a cobalamin-binding domain. Here, by challenging the current paradigm of glycine betaine (GBT) catabolism, we have identified a unique methyltransferase in aerobic environmental bacteria that has a dual function both as a methionine synthase and a GBT methyltransferase. Using the marine bacterium Ruegeria pomeroyi DSS-3 as a model, we demonstrate that a core cobalamin-binding domain (MtgC) and a bidirectional methyltransferase (MtgD) are essential for both methionine synthesis and GBT demethylation. MtgC is phylogenetically distinct from the cobalamin-binding domains of either the classical methionine synthase (MetH) or the GBT methyltransferases found in anaerobic bacteria and archaea. Across the global ocean, mtgC expression is frequently greater than previously known GBT catabolic pathways due to its occurrence in abundant cosmopolitan marine bacteria. Thus, we uncover a unique relationship between GBT catabolism and methionine synthesis in nature and identify a major route for N-osmolyte demethylation in the global ocean.

Prognostic value of D-dimer in treatment and follow up for patients who underwent radiotherapy in advanced lung cancer

Background Lung carcinma, a serious disease commonly recognized at advanced stages and has less favorable outcomes to treatments. This research examines the association between D-dimer values and clinical variables in patients diagnosed with advanced lung cancer, with a focus on their prognostic significance and radiotherapy related outcomes. Methods This retrospective observational descriptive cohort study, including 142 patients with lung cancer. Aa comprehensive analysis, was conducted, including demographic variables,clinical staging, pathology, laboratuary tests, and D-dimer levels measured both before and after the administration of radiotherapy. Results The findings indicated that high pre-RT D-dimer concentrations were significantly assoccciated with advanced stages of disease, worse response of radiotherapy, Eastern Cooperative Oncology Group performance status, and decreased survival outcomes. Radiotherapy response also affects to survival rates with D-dimer values. The findings from both univariate and multivariable survival analyses demonstrated that lower concentrations of D-dimer correlated with better response of radiotherapy, extended overall survival and progression free survival (p: < 0.001). Conclusion These results illustrate the significant role of D-dimer as a valuable biomarker for assessing tumor burden and guiding radiotherapy and other treatment strategies in lung cancer, thereby necessitating further inquiry to evaluate its clinical implications.

Humanization of CD47 enables development of functional human neutrophils via postirradiation remodeling of the bone marrow

Murine and human immune systems differ significantly, particularly within the myeloid lineage. Humanized mice, generated by transplanting human hematopoietic stem, progenitor cells into genetically modified mice, are invaluable to study human immune development and function in vivo. However, a major limitation of current models is suboptimal myelopoiesis, particularly lack of functional human neutrophils, hampering the modeling of human immune responses and chronic diseases. Here, we describe a humanized mouse model, named MaGIC for genes replaced, in the C57Bl/6 N strain, which improves human myelopoiesis and enables development of functional human neutrophils. In MaGIC mice, human cytokines M-CSF/CSF1(M), GM-CSF/CSF2(G) and IL-6(I) are knocked-in replacing mouse genes and murine IL2rg and Rag1 (a) are deleted. Human THPO in these mice supports human hematopoiesis. More importantly, insertion of human CD47 (C) under the control of endogenous mouse CD47 promoter enables xenotransplantation and human neutrophil development. MaGIC mice support all human neutrophil subsets found in human bone marrow and blood, a major improvement. This is achieved by creating a niche postirradiation for human granulocyte–macrophage progenitors via reduced murine CD47 and physiological levels of human CD47. These mice also have mature human monocytes, tissue macrophages, alveolar macrophages, dendritic cells, and NK cells, enabled by humanized M-CSF and GM-CSF. Human neutrophils in MaGIC mice are fully functional in chemotaxis, phagocytosis, reactive oxygen species production, and neutrophil extracellular trap formation in response to inflammation. MaGIC mice address critical gaps in current models and enable incisive translational research on human neutrophils, advancing studies in infectious, autoimmune, and inflammatory diseases.

Understanding disappearances in Mexico City: A data-driven analysis

Mexico is facing an escalating crisis of violence, marked by a sharp increase in disappearances. However, key information remains unknown, such as the typical profile of victims, geographic hotspots, and the relationship between disappearances, economic conditions, and public security. We used a government database of 3,450 disappearances in Mexico City, together with scraped data, to analyze the phenomenon of missing persons. We found that disappearances are not homogeneously distributed along Mexico City, the central district has the highest disappearance rate per capita, which can be attributed to city mobility for job locations. Men account for 62.5% of missing persons, but women aged 15-19 are the most vulnerable group. There is a strong correlation (r=0.95) between reports of drug dealing and disappearances, both of which may be related to the presence of organized crime. Furthermore, when disappearances are normalized to account for mobility related to job locations, a strong negative correlation (r=–0.7) emerges between disappearances and housing prices. This suggests a pattern of socio-economic segregation in disappearances, with higher rates in areas with lower housing prices. Integrating data on disappearances, housing prices, reports of drug dealing, and perception of insecurity for each municipality, we implemented K-means algorithm. Without spatial information, K-means divided Mexico City in west and east. In the east side, people are more vulnerable to disappearances than those in the west side.

Fracture of liquid crystal elastomers

Liquid crystal elastomers (LCEs) are anisotropic, viscoelastic materials integrating polymer networks and liquid crystals. While their mechanical responses have been extensively studied, their fracture behavior remains largely unexplored. Specifically, the effect of the deformation-director coupling on LCE fracture paths is unknown, and fracture criteria for LCEs are not yet established. To address this gap, we combine experimental and theoretical approaches to investigate fracture propagation in LCEs. We stretch edge-cracked monodomain LCE samples, recording their stress-stretch responses and crack paths under varying initial directors and stretching rates. Our findings reveal that cracks can change direction during propagation, which are highly dependent on both the initial director and the stretching rate. To further understand LCE fracture behavior, we develop a rate-dependent phase-field fracture model, which is validated through experiments, and demonstrates the ability to predict complex fracture paths. Our study paves the way for designing LCEs with enhanced fracture properties, imperative for their future applications.

Kelps on the move: Potential future distribution areas in the face of climate change, on the Pacific coast of South America

Kelp forests are critical marine ecosystems that offer key services such as habitat, coastal protection, carbon sequestration, and support for fisheries. Along the temperate Pacific coast of South America, however, these seaweeds have historically been subjected to intense exploitation pressure, given their value as an economic resource. Additionally, they are impacted by oceanographic and climatic factors such as ENSO (El Niño-Southern Oscillation) event and ongoing climate change. The combined effects of these stressors pose a significant threat to their biomass and geographic distribution. Species distribution models under four representative concentration pathways for 2050 were used to assess the current and future potential distribution of two endemic intertidal kelp species, Lessonia berteroana and Lessonia spicata, which represent two of the four primary kelp species targeted by regional fisheries in the region. This approximation allows us to identify future areas of persistence (retained), retreat (lost), and expansion (gained). The results show that the environmental variables that mainly affected the potential distribution were salinity in L. berteroana and surface water temperature for L. spicata. The predictive models suggest that for L. berteroana, the lost area could reach 60.6%, and retained areas could account for 31.6% of the current area. Similarly, for L. spicata, the models indicate a potential loss of 58.6%, with retained areas comprising approximately 58.2% of the current area. Therefore, models predict a significant contraction could lead to the local disappearance of Lessonia species between 14° S and 25° S, profoundly altering coastal ecosystems and diminishing the critical ecosystem services they provide. Our modeling results underscore the urgent need for informed management and conservation strategies for kelp forests, which serve as vital ecosystem engineers. This research is especially critical in the face of climate change and ongoing anthropogenic pressures such as overexploitation. The study provides a robust scientific foundation for proactive measures to mitigate kelp forest decline and preserving their invaluable ecosystem functions along the Pacific coast of South America.

DNA-utilization loci enable exogenous DNA metabolism in gut Bacteroidales

The human gut microbiome plays a central role in nutrient metabolism, yet the fate of exogenous nucleic acids within this ecosystem remains poorly understood. Here, we show that multiple Bacteroidales species efficiently metabolize exogenous DNA, with Bacteroides thetaiotaomicron converting it into the deaminated nucleobases uracil and xanthine. Using genetic and biochemical approaches, we identify ddbABCDEF , a six-gene locus encoding secreted nucleases and an outer membrane transporter, essential for exogenous DNA metabolism in B. thetaiotaomicron . Colonization of gnotobiotic mice with ddbABCDEF mutants reveals that this pathway significantly alters nucleobase pools in a gnotobiotic mouse model. Comparative genomic analyses demonstrate that ddbABCDEF is evolutionarily related to a natural transformation system present in Bacteroidota and has diversified into four distinct subtypes, each linked to unique DNA-processing activities in closely related gut Bacteroidales strains. These findings thus expand our understanding of DNA metabolism in the gut microbiome and reveal a distinctive pathway for nucleobase production with implications for host–microbe interactions.