Yield, cell structure and physiological and biochemical characteristics of rapeseed under waterlogging stress.

Rapeseed (Brassica napus L.) is a major oilseed crop in the middle and lower reaches of the Yangtze River in China. However, it is susceptible to waterlogging stress. This study aimed to investigate the physiological characteristics, cellular changes, and gene expression patterns of rapeseed under waterlogging stress, with the goal of providing a foundation for breeding waterlogging-tolerant rapeseed. The results revealed that waterlogging-tolerant rapeseed exhibited higher levels of soluble sugars and antioxidant enzyme activity, particularly in the roots. Conversely, waterlogging-sensitive rapeseed displayed greater changes in malondialdehyde, proline, and hydrogen peroxide levels. Cellular observations showed that after experiencing waterlogging stress, the intercellular space of rapeseed leaf cells expanded, leading to disintegration of mitochondria and chloroplasts. Moreover, the area of the root xylem increased, the number of vessels grew, and there were signs of mitochondrial disintegration and vacuole shrinkage, with more pronounced changes observed in waterlogging-sensitive rapeseed. Furthermore, significant differences were found in the transcription levels of genes related to anaerobic respiration and flavonoid biosynthesis, and different varieties demonstrated varied responses to waterlogging stress. In conclusion, there are differences in the response of different varieties to waterlogging stress at the levels of morphology, physiological characteristics, cell structure, and gene transcription. Waterlogging-tolerant rapeseed responds to waterlogging stress by regulating its antioxidant defense system. This study provides valuable insights for the development of waterlogging-tolerant rapeseed varieties.

Clostridium difficile infection following colon subtotal resection in a patient with gallstones: A case report and review of literature.

BACKGROUND: Clostridium difficile (C. difficile) infection (CDI) is a rare clinical disease caused by changes in the intestinal microenvironment, which has a variety of causes and a poor prognosis, and for which there is no standardized clinical treatment. CASE SUMMARY: A patient experienced recurrent difficulty in bowel movements over the past decade. Recently, symptoms worsened within the last ten days, leading to a clinic visit due to constipation. The patient was subsequently referred to our department. Preoperatively, the patient was diagnosed with obstructed colon accompanied by gallstones. Empirical antibiotics were administered both before and after surgery to prevent infection. On the fourth day post-surgery, symptoms of CDI emerged. Stool cultures confirmed the presence of C. difficile DNA. Treatment involved a combination of vancomycin and linezolid, resulting in the patient's successful recovery upon discharge. However, the patient failed to adhere to the prescribed medication after discharge and was discovered deceased during a follow-up two months later. CONCLUSION: CDI is the leading cause of nosocomial post-operative care, with limited clinical cases and poor patient prognosis, and comprehensive clinical treatment guidelines are still lacking. This infection can be triggered by a variety of factors, including intestinal hypoxia, inappropriate antibiotic use, and bile acid circulation disorders. In patients with chronic bowel disease and related etiologies, prompt preoperative attention to possible CDI and preoperative bowel preparation is critical. Adequate and prolonged medication should be maintained in the treatment of CDI to prevent recurrence of the disease.

Construction of controlled hyper-crosslinked nanofibrous tubes for Cr(VI) removal: Response surface, kinetics, and isotherm.

Porous organic polymers (POPs) exhibit significant potential for adsorbing toxic metal ions in wastewater. Developing POPs with controlled morphologies is a pivotal direction in this field. This study synthesized a series of novel hyper-crosslinked nanofibrous tubes designated HCNT-Cn (n = 4, 8, 12, 16) via Friedel-Crafts alkylation and quaternization reactions. These reactions were fine-tuned through a post-synthetic strategy involving varying alkyl chain lengths. These materials were characterized using FT-IR, SEM, N2 adsorption-desorption isotherms, among others, and they were specifically evaluated for their ability to adsorb Cr(VI). Among the variants, HCNT-C4 exhibited the highest specific surface area (495.26 m2 g-1), superior hydrophilicity (CA = 48.7°), and optimal adsorption performance. The adsorption kinetics of HCNT-C4 conformed to a pseudo-second-order model, while its adsorption isotherm aligned with the Langmuir model. An investigation into the impact of Cr(VI) removal was conducted using three independent variables in a Central Composite Design (CCD) response surface model, revealing that under optimal conditions, the Cr(VI) removal efficiency reached 98%. Additionally, a mechanism for Cr(VI) adsorption on HCNT-C4 was proposed. It was also found that HCNT-C4 could be reused up to four times, maintaining a removal efficiency of 70%. This study suggests potential applications for removing Cr(VI) from contaminated wastewater.

Variable screening and model construction for prognosis of elderly patients with lower-grade gliomas based on LASSO-Cox regression: a population-based cohort study.

Background: This study aimed to identify prognostic factors for survival and develop a prognostic nomogram to predict the survival probability of elderly patients with lower-grade gliomas (LGGs). Methods: Elderly patients with histologically confirmed LGG were recruited from the Surveillance, Epidemiology, and End Results (SEER) database. These individuals were randomly allocated to the training and validation cohorts at a 2:1 ratio. First, Kaplan-Meier survival analysis and subgroup analysis were performed. Second, variable screening of all 13 variables and a comparison of predictive models based on full Cox regression and LASSO-Cox regression analyses were performed, and the key variables in the optimal model were selected to construct prognostic nomograms for OS and CSS. Finally, a risk stratification system and a web-based dynamic nomogram were constructed. Results: A total of 2307 elderly patients included 1220 males and 1087 females, with a median age of 72 years and a mean age of 73.30 ± 6.22 years. Among them, 520 patients (22.5%) had Grade 2 gliomas, and 1787 (77.5%) had Grade 3 gliomas. Multivariate Cox regression analysis revealed four independent prognostic factors (age, WHO grade, surgery, and chemotherapy) that were used to construct the full Cox model. In addition, LASSO-Cox regression analysis revealed five prognostic factors (age, WHO grade, surgery, radiotherapy, and chemotherapy), and a LASSO model was constructed. A comparison of the two models revealed that the LASSO model with five variables had better predictive performance than the full Cox model with four variables. Ultimately, five key variables based on LASSO-Cox regression were utilized to develop prognostic nomograms for predicting the 1-, 2-, and 5-year OS and CSS rates. The nomograms exhibited relatively good predictive ability and clinical utility. Moreover, the risk stratification system based on the nomograms effectively divided patients into low-risk and high-risk subgroups. Conclusion: Variable screening based on LASSO-Cox regression was used to determine the optimal prediction model in this study. Prognostic nomograms could serve as practical tools for predicting survival probabilities, categorizing these patients into different mortality risk subgroups, and developing personalized decision-making strategies for elderly patients with LGGs. Moreover, the web-based dynamic nomogram could facilitate its use in the clinic.

Structural insights into Frizzled3 through nanobody modulators.

The Wnt receptor Frizzled3 (FZD3) is important for brain axonal development and cancer progression. We report structures of FZD3 in complex with extracellular and intracellular binding nanobodies (Nb). The crystal structure of Nb8 in complex with the FZD3 cysteine-rich domain (CRD) reveals that the nanobody binds at the base of the lipid-binding groove and can compete with Wnt5a. Nb8 fused with the Dickkopf-1 C-terminal domain behaves as a FZD3-specific Wnt surrogate, activating ß-catenin signalling. The cryo-EM structure of FZD3 in complex with Nb9 reveals partially resolved density for the CRD, which exhibits positional flexibility, and a transmembrane conformation that resembles active GPCRs. Nb9 binds to the cytoplasmic region of FZD3 at the putative Dishevelled (DVL) or G protein-binding site, competes with DVL binding, and inhibits GαS coupling. In combination, our FZD3 structures with nanobody modulators map extracellular and intracellular interaction surfaces of functional, and potentially therapeutic, relevance.

Effects of Intrarenal Reflux on Renal Growth in Children With Grades III-V Primary Vesicoureteral Reflux.

The phenomenon of intrarenal reflux (IRR) has been considered a crucial link between vesicoureteral reflux (VUR) and segmental scarring. We conducted a study on renal length in 104 children diagnosed with Grades III-V VUR, with or without IRR, using contrast-enhanced voiding urosonography (ceVUS). The patients were divided into two treatment groups: the conservative antibiotic prophylaxis (CAP) group and the operation group, which were further categorized into two subgroups: the IRR group and the non-IRR group. Our findings revealed an incidence rate of 35.96% (41/114) for IRR occurrence, with 43.42% (33/76) occurring in upper renal segments, 32.89% (25/76) in lower segments, and 23.68% (18/76) in middle segments. In the CAP group where the effects of IRR persisted, the renal growth observed was as follows: IRR group-0.19 ± 0.13 cm; non-IRR group-0.39 ± 0.23 cm; contralateral negative group-0.66 ± 0.35 cm; control group-0.46 ± 0 .25 cm respectively (P < .05). In the operation group, where the effects of IRR were eliminated, the renal growth for the IRR group, non-IRR group, contralateral negative group, and control group was 0.46 ± 0.22 cm, 0.54 ± 0.31 cm, 0.67 ± 0 .42 cm, and 0.36 ± 0.17 cm respectively (P < .005). In conclusion, the presence of IRR can impact renal growth in children diagnosed with Grades III-V primary VUR. Following surgical intervention, the IRR kidney does not exhibit catch-up growth; however, it demonstrates parallel growth alongside the unaffected kidney. Conversely, the non-IRR kidney experiences catch-up growth. Therefore, for children presenting with Grades III-V primary VUR combined with IRR, a more aggressive treatment approach such as surgery is recommended.

The cuproptosis-related signature predicts the prognosis and immune microenvironments of primary diffuse gliomas: a comprehensive analysis.

BACKGROUND: Evidence has revealed a connection between cuproptosis and the inhibition of tumor angiogenesis. While the efficacy of a model based on cuproptosis-related genes (CRGs) in predicting the prognosis of peripheral organ tumors has been demonstrated, the impact of CRGs on the prognosis and the immunological landscape of gliomas remains unexplored. METHODS: We screened CRGs to construct a novel scoring tool and developed a prognostic model for gliomas within the various cohorts. Afterward, a comprehensive exploration of the relationship between the CRG risk signature and the immunological landscape of gliomas was undertaken from multiple perspectives. RESULTS: Five genes (NLRP3, ATP7B, SLC31A1, FDX1, and GCSH) were identified to build a CRG scoring system. The nomogram, based on CRG risk and other signatures, demonstrated a superior predictive performance (AUC of 0.89, 0.92, and 0.93 at 1, 2, and 3 years, respectively) in the training cohort. Furthermore, the CRG score was closely associated with various aspects of the immune landscape in gliomas, including immune cell infiltration, tumor mutations, tumor immune dysfunction and exclusion, immune checkpoints, cytotoxic T lymphocyte and immune exhaustion-related markers, as well as cancer signaling pathway biomarkers and cytokines. CONCLUSION: The CRG risk signature may serve as a robust biomarker for predicting the prognosis and the potential viability of immunotherapy responses. Moreover, the key candidate CRGs might be promising targets to explore the underlying biological background and novel therapeutic interventions in gliomas.

Investigating distinct clinical features and constructing a nomogram model for survival probability in adults with cerebellar high-grade gliomas.

BACKGROUND: The clinical features of cerebellar high-grade gliomas (cHGGs) in adults have not been thoroughly explored. This large-scale, population-based study aimed to comprehensively outline these traits and construct a predictive model. METHODS: Patient records diagnosed with gliomas were collected from various cohorts and analyzed to compare the features of cHGGs and supratentorial HGGs (sHGGs). Cox regression analyses were employed to identify prognostic factors for overall survival and to develop a nomogram for predicting survival probabilities in patients with cHGGs. Multiple machine learning methods were applied to evaluate the efficacy of the predictive model. RESULTS: There were significant differences in prognosis, with SEER-cHGGs showing a median survival of 7.5 months and sHGGs 14.9 months (p < 0.001). Multivariate Cox regression analyses revealed that race, WHO grade, surgical procedures, radiotherapy, and chemotherapy were independent prognostic factors for cHGGs. Based on these factors, a nomogram was developed to predict 1-, 3-, and 5-year survival probabilities, with AUC of 0.860, 0.837, and 0.810, respectively. The model's accuracy was validated by machine learning approaches, demonstrating consistent predictive effectiveness. CONCLUSIONS: Adult cHGGs are distinguished by distinctive clinical features different from those of sHGGs and are associated with an inferior prognosis. Based on these risk factors affecting cHGGs prognosis, the nomogram prediction model serves as a crucial tool for clinical decision-making in patient care.

Analysis of prognostic biomarker models of TXNIP/NLRP3/IL1B inflammasome pathway in patients with acute myeloid leukemia.

Background: Exploring potential biomarkers for predicting clinical outcomes and developing targeted therapies for acute myeloid leukemia (AML) is of utmost importance. This study aimed to investigate the expression pattern of the thioredoxin-interacting protein (TXNIP)/nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) pathway and its role in the prognosis of AML patients. Methods: In this study, we examined the prognostic value of TXNIP/NLRP3 pathway in AML patients using microarray data from Gene Expression Omnibus (GEO) and transcriptome data from the Cancer Genome Atlas (TCGA) to develop a prognostic model and validated the results by quantitative real-time PCR (qRT-PCR) in a validation cohort of 26 AML patients and 18 healthy individuals from Jinan University (JNU) database. Results: Analysis of the GSE13159 database revealed that TXNIP, interleukin 1 beta (IL1B) within the TXNIP/NLRP3 pathway were significantly upregulated and caspase1 (CASP1) was downregulated in AML patients (TXNIP, P = 0.031; IL1B, P = 0.042; CASP1, P = 0.038). Compared to high NLRP3 expression, AML patients with low NLRP3 expression had a longer overall survival (OS) in the GSE12417 dataset (P = 0.004). Moreover, both the training and validation results indicated that lower TXNIP, NLRP3, and IL1B expression were associated with favorable prognosis (GSE12417, P = 0.009; TCGA, P = 0.050; JNU, P = 0.026). According to the receiver operating characteristic curve analysis, this model demonstrated a sensitivity of 84% for predicting three-year survival. These data might provide novel predictors for AML outcome and direction for further investigation of the possibility of using TXNIP/NLRP3/IL1B genes in novel targeted therapies for AML.

Bridging the STRONG Gap: Call to Optimize Heart Failure Treatment After Hospitalization in Women and Men in Taiwan.

The benefits of rapidly up-titrating evidence-based treatments following heart failure (HF) hospitalizations were demonstrated in the The Safety, Tolerability and Efficacy of Rapid Optimization, Helped by NT-proBNP Testing, of Heart Failure Therapies (STRONG-HF) trial and emphasized in contemporary HF guidelines. We aimed to assess up-titration patterns of guideline-directed medical treatments in the Taiwanese HF population. Combining data from the Taiwan Society of Cardiology - Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry and the Treatment with Angiotensin Receptor neprilysin inhibitor for Taiwan Acute Heart Failure (TAROT-AHF) study cohort, we formed the "Taiwan real-world cohort". We compared these data with subgroups of patients with left ventricular ejection fraction ≤40% in the STRONG-HF trial. Patients in the Taiwan cohort exhibited similar blood pressure, heart rate and N-terminal pro B-type natriuretic peptide levels at discharge compared with those in the STRONG-HF trial. A higher proportion of patients in the STRONG-HF high-intensity care group received up-titrations compared with those in the usual care group and the Taiwan cohort. Composite all-cause mortality or HF hospitalization at 180 days for patients in the high-intensity care group, usual care group, and Taiwan cohort were 17.4%, 23.7%, and 31.9%, respectively, with differences largely contributed by HF hospitalization (10.1%, 17.9%, and 27.6%, respectively), whereas all-cause mortality rates were similar (11.0%, 9.6%, and 9.3%, respectively). Gender did not affect this trend. In conclusion, our data highlights a treatment gap between the STRONG-HF trial and real-world practices in Taiwan, urging prompt optimization of HF therapy.

Utility of protein-protein binding surfaces composed of anti-parallel alpha-helices and beta-sheets selected by phage display.

Over the past 3 decades, a diverse collection of small protein domains have been used as scaffolds to generate general purpose protein-binding reagents using a variety of protein display and enrichment technologies. To expand the repertoire of scaffolds and protein surfaces that might serve this purpose, we have explored the utility of (i) a pair of anti-parallel alpha-helices in a small highly disulfide-bonded 4-helix bundle, the CC4 domain from reversion-inducing Cysteine-rich Protein with Kazal Motifs and (ii) a concave beta-sheet surface and two adjacent loops in the human FN3 domain, the scaffold for the widely used monobody platform. Using M13 phage display and next generation sequencing, we observe that, in both systems, libraries of ∼30 million variants contain binding proteins with affinities in the low µM range for baits corresponding to the extracellular domains of multiple mammalian proteins. CC4- and FN3-based binding proteins were fused to the N- and/or C-termini of Fc domains and used for immunostaining of transfected cells. Additionally, FN3-based binding proteins were inserted into VP1 of AAV to direct AAV infection to cells expressing a defined surface receptor. Finally, FN3-based binding proteins were inserted into the Pvc13 tail fiber protein of an extracellular contractile injection system particle to direct protein cargo delivery to cells expressing a defined surface receptor. These experiments support the utility of CC4 helices B and C and of FN3 beta-strands C, D, and F together with adjacent loops CD and FG as surfaces for engineering general purpose protein-binding reagents.

Effects of short- and long-term plant functional group loss on alpine meadow community structure and soil nutrients.

The rapid loss of global biodiversity can greatly affect the normal functioning of ecosystems. However, how biodiversity losses affect plant community structure and soil nutrients is unclear. We conducted a field experiment to examine the short- and long-term effects of removing plant functional groups (Gramineae, Cyperaceae, legumes, and forbs) on the interrelationships among the species diversity, productivity, community structure, and soil nutrients in an alpine meadow ecosystem at Menyuan County, Qinghai Province. The variations in the species richness, above- and belowground biomass of the community gradually decreased over time. Species richness and productivity were positively correlated, and this correlation tended to be increasingly significant over time. Removal of the Cyperaceae, legumes, and other forbs resulted in fewer Gramineae species in the community. Soil total nitrogen, phosphorus, organic matter, and moisture contents increased significantly in the legume removal treatment. The removal of other forbs led to the lowest negative cohesion values, suggesting that this community may have difficulty recovering its previous equilibrium state within a short time. The effects of species removal on the ecosystem were likely influenced by the species structure and composition within the community. Changes in the number of Gramineae species indicated that they were more sensitive and less resistant to plant functional group removal. Legume removal may also indirectly cause distinct community responses through starvation and compensation effects. In summary, species loss at the community level led to extensive species niche shifts, which caused community resource redistribution and significant changes in community structure.

Lactate drives CD38 signaling to promote Epithelial-Mesenchymal Transition through Snail induction in non-small cell lung cancer cells.

CD38 is the main NADase in mammalian cells. It regulates the homeostasis of nicotinamide adenine dinucleotide (NAD+) and extracellular nucleotides. Its function plays an important role in infection and aging. However, its potential functions in tumor cells have not been fully elucidated. In the present study, we demonstrated that lactate, which is derived from tumor metabolism remodeling, upregulates the expression of CD38 through OXPHOS-driven Hippo-TAZ pathway. The highly expressed CD38 converts NAD + to adenosine through the CD203a/CD73 complex and adenosine binds and activates its receptor A2AR, inducing the expression of Snail and promoting the invasion and metastasis of lung cancer cells. This finding elucidates a new perspective on the interplay between NAD + metabolism and glycolysis in tumor development.

Comprehensive environmental performance of bottle-to-bottle recycling of PET bottles based on deposit-refund system in China.

Polyethylene terephthalate (PET) is a widely used packaging material and has high value in recycling. However, under China's dominant informal recycling system, most PET bottles are downcycled into fibers. The deposit-refund system (DRS) is considered a feasible mechanism to facilitate the high-value recycling of PET bottles. To comparatively evaluate the environmental performance [reduction of greenhouse gas (GHG) and pollutant emissions] under different scenarios using life cycle assessments, including the current system based on informal recycling, an improved system with a larger contribution from the source separation of municipal solid waste, and evolving systems with DRS application, five scenarios were set up. The DRS can reduce GHG emissions and the comprehensive environmental impact by 0.538 kg CO2 /kg PET bottles and 1.73 × 10-3 PE/kg PET bottles, respectively, compared to informal recycling. It can be concluded that the DRS-based recycling approach and the bottle-to-bottle recycling provide the substantial emission reduction potential of GHGs and pollutants.

A Systematic Review on Password Guessing Tasks.

Recently, many password guessing algorithms have been proposed, seriously threatening cyber security. In this paper, we systematically review over thirty methods for password guessing published between 2016 and 2023. First, we introduce a taxonomy for classifying the existing methods into trawling guessing and targeted guessing. Second, we present an extensive benchmark dataset that can assist researchers and practitioners in successive works. Third, we conduct a bibliometric analysis to present trends in this field and cross-citation between reviewed papers. Further, we discuss the open challenges of password guessing in terms of diverse application scenarios, guessing efficiency, and the combination of traditional and deep learning methods. Finally, this review presents future research directions to guide successive research and development of password guessing.

Prognostic nomogram models for predicting survival probability in elderly glioblastoma patients.

PURPOSE: To investigate the prognostic factors of survival and develop a predictive nomogram model for elderly GBM patients. METHODS: Elderly patients (> = 65 years) with histologically diagnosed GBM were extracted from the SEER database. Survival analysis of overall survival (OS) was performed by Kaplan-Meier analysis. Univariate and multivariate Cox regression analyses were used to determine independent prognostic factors and these factors were used to further construct the nomogram model. RESULTS: A total of 9068 elderly GBM patients (5122 males and 3946 females) were included, with a median age of 72 years (65-96 years). All patients were divided randomly into the training group (n = 6044) and the validation group (n = 3024) by a ratio of 2:1. Cox regression analyses on OS showed eight independent prognostic factors (race, age, tumor side, tumor size, metastasis, surgery, radiotherapy, and chemotherapy) in the training cohort. Also, seven variables (except for race) were identified on CSS in the training group. By comprising these variables, the nomogram models on OS and CSS for predicting the 6-month, 1-year, and 2-year survival probability were constructed and exhibited moderate consistency, respectively. Then, they could be validated well in the validation cohort and by C-index, time-dependent ROC curve, calibration plot, and DCA curve. CONCLUSIONS: Nomogram models on OS and CSS could provide an applicable tool to predict the survival probability and provide clinical references regarding treatment strategies and prognosis.

Development and Performance Evaluation of Integrated Hybrid Power Module for Three-Phase Servo Motor Applications.

This study aims to develop a 30 kHz/12 kW silicon carbide (SiC)/Si integrated hybrid power module (iHPM) for variable frequency drive applications, particularly industrial servo motor control, and, additionally, to theoretically and experimentally assess its dynamic characteristics and efficiency during operation. This iHPM integrates a brake circuit, a three-phase Si rectifier, and a three-phase SiC inverter within a single package to achieve a minimal current path. A space-vector pulse width modulation (SVPWM) scheme is used to control the inverter power switches. In order to reduce parasitic inductance and power loss, an inductance cancellation design is implemented in the Si rectifier and SiC inverter. The switching transients and their parasitic effects during a three-phase operation are assessed through an electromagnetic-circuit co-simulation model, by which the power loss and efficiency of the iHPM are estimated. The modeled parasitic inductance of the inverter is validated through inductance measurement, and the effectiveness of the simulated results in terms of switching transients and efficiency is verified using the experimental results of the double pulse test and open-loop inverter operation, respectively. In addition, the power loss and efficiency of the SiC MOSFET inverter are experimentally compared against those of a commercial Si IGBT inverter.

Antibody Display Technology (ADbody) to Present Challenging and Unstable Target Proteins on Antibodies.

Antibodies are the major components of adaptive immunity for the recognition of diverse antigens. Six complementarity-determining regions (CDRs) from each heavy chain and light chain present the antigen-binding site, which determines the antigen-binding specificity. Here, we describe the detailed method of a novel display technology termed antibody display technology (ADbody) (Hsieh and Chang, bioRxiv, 2021), based on the novel structure of human antibodies from malaria-endemic regions of Africa (Hsieh and Higgins, eLife 6:e27311, 2017). The principle of ADbody is to insert proteins of interest (POI) into the heavy-chain CDR3 while still retaining the biological function of POI on the antibody. In this chapter, we described how to use the ADbody method to display challenging and unstable POI on the antibody in mammalian cells. Collectively, this method is designed to provide an alternative outside the current display systems and to generate novel synthetic antibodies.

Structure of WNT inhibitor adenomatosis polyposis coli down-regulated 1 (APCDD1), a cell-surface lipid-binding protein.

Diverse extracellular proteins negatively regulate WNT signaling. One such regulator is adenomatosis polyposis coli down-regulated 1 (APCDD1), a conserved single-span transmembrane protein. In response to WNT signaling in a variety of tissues, APCDD1 transcripts are highly up-regulated. We have determined the three-dimensional structure of the extracellular domain of APCDD1, and this structure reveals an unusual architecture consisting of two closely apposed ß-barrel domains (ABD1 and ABD2). ABD2, but not ABD1, has a large hydrophobic pocket that accommodates a bound lipid. The APCDD1 ECD can also bind to WNT7A, presumably via its covalently bound palmitoleate, a modification that is common to all WNTs and is essential for signaling. This work suggests that APCDD1 functions as a negative feedback regulator by titrating WNT ligands at the surface of responding cells.