Serratia plymuthica HK9-3 enhances tomato resistance against Phytophthora capsici by modulating antioxidant defense systems and rhizosphere micro-ecological condition.

Tomatoes are frequently challenged by various pathogens, among which Phytophthora capsici (P. capsici) is a destructive soil-borne pathogen that seriously threatens the safe production of tomatoes. Plant growth-promoting rhizobacteria (PGPR) positively induced plant resistance against multiple pathogens. However, little is known about the role and regulatory mechanism of PGPR in tomato resistance to P. capsici. Here, we identified a new strain Serratia plymuthica (S. plymuthica), HK9-3, which has a significant antibacterial effect on P. capsici infection. Meanwhile, stable colonization in roots by HK9-3, even under P. capsici infection, improved tomato growth parameters, root system architecture, photosynthetic capacity, and boosted biomass. Importantly, HK9-3 colonization significantly alleviated the damage caused by P. capsici infection through enhancing ROS scavenger ability and inducing antioxidant defense system and pathogenesis-related (PR) proteins in leaves, as evidenced by elevating the activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and chitinase, ß-1,3-glucanase, and increasing the transcripts of POD, SOD, CAT, APX1, PAL1, PAL2, PAL5, PPO2, CHI17 and ß-1,3-glucanase genes. Notably, HK9-3 colonization not only effectively improved soil microecology and soil fertility, but also significantly enhanced fruit yield by 44.6% and improved quality. Our study presents HK9-3 as a promising and effective solution for controlling P. capsici infection in tomato cultivation while simultaneously promoting plant growth and increasing yield, which may have implications for P. capsici control in vegetable production.

Co-crystal structure provides insights on transaminase CrmG recognition amino donor L-Arg.

ω-transaminase has attracted growing attention for chiral amine synthesis, although it commonly suffers from severe by-product inhibition. ω-transaminase CrmG is critical for the biosynthesis of Caerulomycin A, a natural product that possesses broad bioactivity, including immunosuppressive and anti-cancer. Compared to L-Arg, amino donor L-Glu, L-Gln or L-Ala is more preferred by CrmG. In this study, we determined the crystal structure of CrmG in complex with amino donor L-Arg, unveiling the detailed binding mode. Specifically, L-Arg exhibits an extensive contact with aromatic residues F207 and W223 on the roof of CrmG active site via cation-π network. This interaction may render the deamination by-product of L-Arg to be an inhibitor against PMP-bound CrmG by stabilizing its flexible roof, thus reducing the reactivity of L-Arg as an amino donor for CrmG. These data provide further evidence to support our previous proposal that CrmG can overcome inhibition from those by-products that are not able to stabilize the flexible roof of active site in PMP-bound CrmG. Thus, our result can not only facilitate the biosynthesis of CRM A but also be beneficial for the rational design of ω-transaminase to bypass by-product inhibition.

Efficacy and Safety of Neoadjuvant Chemoimmunotherapy in Resectable Esophageal Squamous Cell Carcinoma: A Meta-analysis.

PURPOSE: This study aimed to summarize the efficacy and safety of neoadjuvant chemoimmunotherapy in resectable esophageal squamous cell carcinoma (ESCC). METHODS: Literature focusing on the efficacy and safety of neoadjuvant immunotherapy or chemoimmunotherapy in resectable ESCC published before June 2022 was retrieved from PubMed, Embase, Cochrane Library, and Web of Science. The risk of bias was assessed using the Cochrane risk-of-bias assessment tool. Subgroup and sensitivity analyses were further performed. RESULTS: A total of 452 patients from 15 studies were included in this meta-analysis. All of the studies explored the efficacy and safety of neoadjuvant chemoimmunotherapy. The pooled major pathological response (MPR) rate and pathological complete response (PCR) rate were 58.3% and 32.9%, respectively. The pooled incidence of treatment-related adverse events (TRAEs) and serious adverse events (SAEs) were 91.6% and 19.4%, respectively. The pooled R0 resection rate was 92.8%, and the resection rate was 81.1%. Incidence of anastomotic leakage, pulmonary infection, and postoperative hoarseness were 10.7%, 21.3%, and 13.0%, respectively. Compared with 2 cycles of neoadjuvant therapy, patients who received > 2 cycles of neoadjuvant therapy showed higher MPR rate (57.3% vs. 61.1%) and PCR rate (30.6% vs. 37.9%), and the incidence of TRAEs (89.2% vs. 98.9%) tended to be higher. However, no significant difference was found (P > 0.05). Two cycles of neoadjuvant therapy showed higher R0 resection rate and resection rate (R0 resection rate: 96.0% vs. 87.8%, P = 0.02; resection rate: 85.6% vs. 74.7%, P = 0.01). Pembrolizumab- and tislelizumab-based neoadjuvant therapy showed higher MPR rate (72.4% and 72.2%) and PCR rate (41.5 % and 50.0%). Compared with other ICIs, tislelizumab-based neoadjuvant therapy showed lower R0 resection rate (80.5%). The pooled incidence of SAEs for pembrolizumab-based neoadjuvant therapy (2.0%) was lower. Camrelizumab-based neoadjuvant therapy showed lower incidence of pulmonary infection (11.5%). CONCLUSIONS: Neoadjuvant chemoimmunotherapy is effective and safe for resectable ESCC.

You Exude What You Eat: How Carbon-, Nitrogen-, and Sulfur-Rich Organic Substrates Shape Microbial Community Composition and the Dissolved Organic Matter Pool.

Phytoplankton is the major source of labile organic matter in the sunlit ocean, and they are therefore key players in most biogeochemical cycles. However, studies examining the heterotrophic bacterial cycling of specific phytoplankton-derived nitrogen (N)- and sulfur (S)-containing organic compounds are currently lacking at the molecular level. Therefore, the present study investigated how the addition of N-containing (glycine betaine [GBT]) and S-containing (dimethylsulfoniopropionate [DMSP]) organic compounds, as well as glucose, influenced the microbial production of new organic molecules and the microbial community composition. The chemical composition of microbial-produced dissolved organic matter (DOM) was analyzed by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) demonstrating that CHO-, CHON-, and CHOS-containing molecules were enriched in the glucose, GBT, and DMSP experiments, respectively. High-throughput sequencing showed that Alteromonadales was the dominant group in the glucose, while Rhodobacterales was the most abundant group in both the GBT and DMSP experiments. Cooccurrence network analysis furthermore indicated more complex linkages between the microbial community and organic molecules in the GBT compared with the other two experiments. Our results shed light on how different microbial communities respond to distinct organic compounds and mediate the cycling of ecologically relevant compounds. IMPORTANCE Nitrogen (N)- and sulfur (S)-containing compounds are normally considered part of the labile organic matter pool that fuels heterotrophic bacterial activity in the ocean. Both glycine betaine (GBT) and dimethylsulfoniopropionate (DMSP) are representative N- and S-containing organic compounds, respectively, that are important phytoplankton cellular compounds. The present study therefore examined how the microbial community and the organic matter they produce are influenced by the addition of carbohydrate-containing (glucose), N-containing (GBT), and S-containing (DMSP) organic compounds. The results demonstrate that when these carbon-, N-, and S-rich compounds are added separately, the organic molecules produced by the bacteria growing on them are enriched in the same elements. Similarly, the microbial community composition was also distinct when different compounds were added as the substrate. Overall, this study demonstrates how the microbial communities metabolize and transform different substrates thereby, expanding our understanding of the complexity of links between microbes and substrates in the ocean.

Design, synthesis, discovery and SAR of the fused tricyclic derivatives of indoline and imidazolidinone against DENV replication and infection.

Dengue virus, belonging to a genus Flavivirus, caused public health problem in recent years. One controversial vaccine of DENV was approved and there is no antiviral for the clinic treatment of DENV, therefore, efficient antivirals to DENV are of great medical significance. In this study, we conducted the design, synthesis, cell-based and target-based activity evaluation of 28 compounds based on indoline structural skeleton against DENV infection. Among them, 13 active compounds against DENV infection were discovered and their structure-activity relationship (SAR) was summarized. In this study, indoline carbohydrazine has derived more active compounds than indoline carboamide. It is discovered that TBS group exhibits a good pharmacophore to enhance anti-DENV activity. Further exploration indicated that post-treatment acts as effective time of addition and compound 15 targeting the post-entry stages of DENV2 viral life cycle. SPR imaging results support there are strong interaction of 13 and 15 with RdRp and compounds 13 and 15 reduce RdRp enzymatic activity, revealing that RdRp of DENV NS5 is the drug target for these series of compounds. Molecular docking deciphered the relationship of the structural feature with the putative binding mode by 13 and 15 with RdRp domain of DENV2 NS5 by hydrogen bonds and hydrophobic interactions to establish the fitted low energy conformation. Future studies will focus on designing more potent inhibitors for the treatment and prevention of dengue virus replication and infection, and understanding the more profound underlying structural features of inhibitors and drug action of the mechanism.

DDX24 Mutations Associated With Malformations of Major Vessels to the Viscera.

Vascular malformations present diagnostic and treatment challenges. In particular, malformations of vessels to the viscera are often diagnosed late or incorrectly due to the insidious onset and deep location of the disease. Therefore, a better knowledge of the genetic mutations underlying such diseases is needed. Here, we evaluated a four-generation family carrying vascular malformations of major vessels that affect multiple organs, which we named "multiorgan venous and lymphatic defect" (MOVLD) syndrome. Genetic analyses identified an association between a mutation in DEAD-box helicase 24 (DDX24), a gene for which the function is largely unknown, and MOVLD. Next, we screened 161 patients with sporadic vascular malformations of similar phenotype to our MOVLD family and found the same mutation or one of the two additional DDX24 mutations in 26 cases. Structural modeling revealed that two of the mutations are located within the adenosine triphosphate-binding domain of DDX24. Knockdown of DDX24 expression in endothelial cells resulted in elevated migration and tube formation. Transcriptomic analysis linked DDX24 to vascular system-related functions. Conclusion: Our results provide a link between DDX24 and vascular malformation and indicate a crucial role for DDX24 in endothelial cell functions; these findings create an opportunity for genetic diagnosis and therapeutic targeting of malformations of vessels to the viscera.

Ligand binding and heterodimerization with retinoid X receptor α (RXRα) induce farnesoid X receptor (FXR) conformational changes affecting coactivator binding.

Nuclear receptor farnesoid X receptor (FXR) functions as the major bile acid sensor coordinating cholesterol metabolism, lipid homeostasis, and absorption of dietary fats and vitamins. Because of its central role in metabolism, FXR represents an important drug target to manage metabolic and other diseases, such as primary biliary cirrhosis and nonalcoholic steatohepatitis. FXR and nuclear receptor retinoid X receptor α (RXRα) form a heterodimer that controls the expression of numerous downstream genes. To date, the structural basis and functional consequences of the FXR/RXR heterodimer interaction have remained unclear. Herein, we present the crystal structures of the heterodimeric complex formed between the ligand-binding domains of human FXR and RXRα. We show that both FXR and RXR bind to the transcriptional coregulator steroid receptor coactivator 1 with higher affinity when they are part of the heterodimer complex than when they are in their respective monomeric states. Furthermore, structural comparisons of the FXR/RXRα heterodimers and the FXR monomers bound with different ligands indicated that both heterodimerization and ligand binding induce conformational changes in the C terminus of helix 11 in FXR that affect the stability of the coactivator binding surface and the coactivator binding in FXR. In summary, our findings shed light on the allosteric signal transduction in the FXR/RXR heterodimer, which may be utilized for future drug development targeting FXR.

Structural insights into the binding mechanism of IDO1 with hydroxylamidine based inhibitor INCB14943.

IDO1 (indoleamine 2, 3-dioxygenase 1), a well characterized immunosuppressive enzyme, has attracted growing attention as a potential target for cancer immunotherapy. Hydroxylamidine compounds INCB024360 and INCB14943 (INCB024360 analogue) are highly effective IDO1 inhibitors. INCB024360 is undergoing clinical trials for treatment of various types of human cancer. Here, we determined the co-crystal structure of IDO1 and INCB14943, and elucidate the detailed binding mode. INCB14943 binds to heme iron in IDO1 protein through the oxime nitrogen. Further analysis also reveals that a halogen bonding interaction between the chlorine atom (3-Cl) of INCB14943 and the sulphur atom of C129 significantly improves the inhibition activity against IDO1. Comparing with the other reported inhibitors, the oxime nitrogen and halogen bond interaction are identified as the unique features of INCB14943 among the IDO1 inhibitors. Thus, our study provides novel insights into the interaction between a small molecule inhibitor INCB14943 and IDO1 protein. The structural information will facilitate future IDO1 inhibitor design.

Malassezia globosa MgMDL2 lipase: Crystal structure and rational modification of substrate specificity.

Lipases play an important role in physiological metabolism and diseases, and also have multiple industrial applications. Rational modification of lipase specificity may increase the commercial utility of this group of enzymes, but is hindered by insufficient mechanistic understanding. Here, we report the 2.0 Å resolution crystal structure of a mono- and di-acylglycerols lipase from Malassezia globosa (MgMDL2). Interestingly, residues Phe278 and Glu282 were found to involve in substrate recognition because mutation on each residue led to convert MgMDL2 to a triacylglycerol (TAG) lipase. The Phe278Ala and Glu282Ala mutants also acquired ability to synthesize TAGs by esterification of glycerol and fatty acids. By in silicon analysis, steric hindrance of these residues seemed to be key factors for the altered substrate specificity. Our work may shed light on understanding the unique substrate selectivity mechanism of mono- and di-acylglycerols lipases, and provide a new insight for engineering biocatalysts with desired catalytic behaviors for biotechnological application.

Absolute Position Sensing Based on a Robust Differential Capacitive Sensor with a Grounded Shield Window.

A simple differential capacitive sensor is provided in this paper to measure the absolute positions of length measuring systems. By utilizing a shield window inside the differential capacitor, the measurement range and linearity range of the sensor can reach several millimeters. What is more interesting is that this differential capacitive sensor is only sensitive to one translational degree of freedom (DOF) movement, and immune to the vibration along the other two translational DOFs. In the experiment, we used a novel circuit based on an AC capacitance bridge to directly measure the differential capacitance value. The experimental result shows that this differential capacitive sensor has a sensitivity of 2 × 10(-4) pF/µm with 0.08 µm resolution. The measurement range of this differential capacitive sensor is 6 mm, and the linearity error are less than 0.01% over the whole absolute position measurement range.

Residue Asn277 affects the stability and substrate specificity of the SMG1 lipase from Malassezia globosa.

Thermostability and substrate specificity are important characteristics of enzymes for industrial application, which can be improved by protein engineering. SMG1 lipase from Malassezia globosa is a mono- and diacylglycerol lipase (MDL) that shows activity toward mono- and diacylglycerols, but no activity toward triacylglycerols. SMG1 lipase is considered a potential biocatalyst applied in oil/fat modification and its crystal structure revealed that an interesting residue-Asn277 may contribute to stabilize loop 273-278 and the 3104 helix which are important to enzyme characterization. In this study, to explore its role in affecting the stability and catalytic activity, mutagenesis of N277 with Asp (D), Val (V), Leu (L) and Phe (F) was conducted. Circular dichroism (CD) spectral analysis and half-life measurement showed that the N277D mutant has better thermostability. The melting temperature and half-life of the N277D mutant were 56.6 °C and 187 min, respectively, while that was 54.6 °C and 121 min for SMG1 wild type (WT). Biochemical characterization of SMG1 mutants were carried out to test whether catalytic properties were affected by mutagenesis. N277D had similar enzymatic properties as SMG1 WT, but N277F showed a different substrate selectivity profile as compared to other SMG1 mutants. Analysis of the SMG1 3D model suggested that N277D formed a salt bridge via its negative charged carboxyl group with a positively charged guanidino group of R227, which might contribute to confer N277D higher temperature stability. These findings not only provide some clues to understand the molecular basis of the lipase structure/function relationship but also lay the framework for engineering suitable MDL lipases for industrial applications.

Structure of sorting nexin 11 (SNX11) reveals a novel extended phox homology (PX) domain critical for inhibition of SNX10-induced vacuolation.

Sorting nexins are phox homology (PX) domain-containing proteins involved in diverse intracellular endosomal trafficking pathways. The PX domain binds to certain phosphatidylinositols and is recruited to vesicles rich in these lipids. The structure of the PX domain is highly conserved, containing a three-stranded ß-sheet, followed by three α-helices. Here, we report the crystal structures of truncated human SNX11 (sorting nexin 11). The structures reveal that SNX11 contains a novel PX domain, hereby named the extended PX (PXe) domain, with two additional α-helices at the C terminus. We demonstrate that these α-helices are indispensible for the in vitro functions of SNX11. We propose that this PXe domain is present in SNX10 and is responsible for the vacuolation activity of SNX10. Thus, this novel PXe domain constitutes a structurally and functionally important PX domain subfamily.

Structure of human SNX10 reveals insights into its role in human autosomal recessive osteopetrosis.

Sorting nexin 10 (SNX10), the unique member of the SNX family having vacuolation activity in cells, was shown to be involved in the development of autosomal recessive osteopetrosis (ARO) in recent genetic studies. However, the molecular mechanism of the disease-related mutations affecting the biological function of SNX10 is unclear. Here, we report the crystal structure of human SNX10 to 2.6 Å resolution. The structure reveals that SNX10 contains the extended phox-homology domain we previously proposed. Our study provides the structural details of those disease-related mutations. Combined with the vacuolation study of those mutations, we found that Tyr32 and Arg51 are important for the protein stability and both play a critical role in vacuolation activity, while Arg16Leu may affect the function of SNX10 in osteoclast through protein-protein interactions.

Comparison of efficacy and safety between neoadjuvant chemotherapy and neoadjuvant immune checkpoint inhibitors combined with chemotherapy for locally advanced esophageal squamous cell carcinoma: a systematic review and meta-analysis.

BACKGROUND: The application of neoadjuvant immune checkpoint inhibitors combined with chemotherapy (NICT) in treating locally advanced oesophageal squamous cell carcinoma (ESCC) is a subject of considerable research interest. In light of this, we undertook a comprehensive meta-analysis aiming to compare the efficacy and safety of this novel approach with conventional neoadjuvant chemotherapy (NCT) in the management of ESCC. METHODS: A systematic search was conducted in PubMed, Embase, Cochrane Library, and Web of Science to gather relevant literature on the efficacy and safety of NICT compared to conventional NCT in locally advanced ESCC published before June 2023. Effect indicators, including odds ratios (ORs) with associated 95% CIs, were employed to evaluate the safety and efficacy outcomes. The risk of bias was assessed using the Cochrane bias risk assessment tool, and s ubgroup analysis and sensitivity analysis were conducted to investigate the findings further. RESULTS: A total of nine studies qualified for the meta-analysis, all of which investigated the efficacy and safety of NICT compared to conventional NCT. The pooled rates of pathologic complete response and major pathologic response in the NICT group were significantly higher compared to the NCT group, with values of 26.9% versus 8.3% ( P <0.00001) and 48.1% versus 24.6% ( P <0.00001), respectively. The ORs for achieving pathologic complete response and major pathologic response were 4.24 (95% CI, 2.84-6.32, I 2 =14%) and 3.30 (95% CI, 2.31-4.71, I 2 =0%), respectively, indicating a significant advantage for the NICT group. Regarding safety outcomes, the pooled incidences of treatment-related adverse events and serious adverse events in the NICT group were 64.4% and 11.5%, respectively, compared to 73.8% and 9.3% in the NCT group. However, there were no significant differences observed between the two groups in terms of treatment-related adverse events (OR=0.67, 95% CI, 0.29-1.54, P =0.35, I 2 =58%) or serious adverse events (OR=1.28, 95% CI, 0.69-2.36, P =0.43, I 2 =0%). Furthermore, no significant differences were found between the NICT and NCT groups regarding R0 resection rates, anastomotic leakage, pulmonary infection, and postoperative hoarseness. CONCLUSIONS: Neoadjuvant immune checkpoint inhibitors combined with chemotherapy demonstrate efficacy and safety in treating resectable oesophageal squamous cell carcinoma. Nevertheless, additional randomized trials are required to confirm the optimal treatment regimen.

Cellulose nanofiber hydrogel with high conductivity electrolytes for high voltage flexible supercapacitors.

Although flexible double layer capacitors based on hydrogels overcome the drawbacks of commercial double layer capacitors such as low safety and non-deformability, it is still considered as attractive challenges to achieve high conductivity for hydrogel electrolytes as well as high operating voltages for hydrogel flexible supercapacitors. In this paper, ion migration channels were engineered by immobilizing positive and negative charges on polymer skeleton and dispersing cellulose nanofibers in the polymerized polyelectrolyte network, providing ultra-high ionic conductivity (103 mS cm-1). In addition, K3[Fe(CN)6] was introduced through a soaking method, leading to redox reactions on the surface of carbon electrode during charging and discharging, supporting a relatively wide voltage window (1.8 V). Moreover, the specific capacitance at high current remained 55 % of the specific capacitance at low current, indicating excellent rate performance. In addition, the device displayed high cycling stability (80.05 % after 10,000 cycles). Notably, we successfully light up the red LED with only one device. Accordingly, this work provides a feasible design concept for the development of cellulose nanofibers (CNF) hydrogel-based solid-state electrolyte with high conductivity for flexible supercapacitors with wide potential window and high energy density.

Prognostic value of inflammatory nutritional scores in locally advanced esophageal squamous cell carcinoma patients undergoing neoadjuvant chemoimmunotherapy: a multicenter study in China.

Objective: This study investigates the prognostic significance of inflammatory nutritional scores in patients with locally advanced esophageal squamous cell carcinoma (LA-ESCC) undergoing neoadjuvant chemoimmunotherapy. Methods: A total of 190 LA-ESCC patients were recruited from three medical centers across China. Pre-treatment laboratory tests were utilized to calculate inflammatory nutritional scores. LASSO regression and multivariate logistic regression analyses were conducted to pinpoint predictors of pathological response. Kaplan-Meier and Cox regression analyses were employed to assess disease-free survival (DFS) prognostic factors. Results: The cohort comprised 154 males (81.05%) and 36 females (18.95%), with a median age of 61.4 years. Pathological complete response (pCR) was achieved in 17.38% of patients, while 44.78% attained major pathological response (MPR). LASSO and multivariate logistic regression analyses identified that hemoglobin, albumin, lymphocyte, and platelet (HALP) (P=0.02) as an independent predictors of MPR in LA-ESCC patients receiving neoadjuvant chemoimmunotherapy. Kaplan-Meier and log-rank tests indicated that patients with low HALP, MPR, ypT1-2, ypN0 and, ypTNM I stages had prolonged DFS (P < 0.05). Furthermore, univariate and multivariate Cox regression analyses underscored HALP (P = 0.019) and ypT (P = 0.029) as independent predictive factors for DFS in ESCC. Conclusion: Our study suggests that LA-ESCC patients with lower pre-treatment HALP scores exhibit improved pathological response and reduced recurrence rate. As a comprehensive index of inflammatory nutritional status, pre-treatment HALP may be a reliable prognostic marker in ESCC patients undergoing neoadjuvant chemoimmunotherapy.

Association between per- and polyfluoroalkyl substances exposure and prevalence of chronic obstructive pulmonary disease: The mediating role of serum albumin.

BACKGROUND: No study has examined the association between per- and polyfluoroalkyl substances (PFAS) exposure and chronic obstructive pulmonary disease (COPD) risk. This study aims to explore this relationship. METHODS: This study enrolled 4541 individuals who had available data on PFAS, COPD, and covariates from NHANES 2007-2018. Serum PFAS including perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) were analyzed, because of high detective rates. Considering the skew distribution of PFAS levels, the natural logarithm-transformed PFAS (Ln-PFAS) was used. Logistic regression analysis, restricted cubic spline (RCS), and weighted quantile sum (WQS) regression were performed to explore the single, nonlinear, and mixed effects. A mediating analysis was used to evaluate the mediated effects of albumin. RESULTS: Individuals with COPD had higher levels of PFHxS, PFNA, PFOA, and PFOS compared to those without COPD. Ln-PFNA (OR males: 1.92, 95 % CI:1.31 to 2.80, P: <0.001; OR females: 1.07, 95 % CI: 0.81 to 1.40, P: 0.636) and ln-PFOA (OR males: 2.17, 95 % CI:1.38 to 3.41, P: <0.001; OR females: 1.49, 95 % CI: 1.08 to 2.05, P: 0.016) were associated with COPD risk especially in males. The interaction between PFNA exposure and sex on COPD risk was significant (P interaction: <0.001). The RCS curve demonstrated the nonlinear relationship between the ln-PFOA (P nonlinear:0.001), ln-PFNA (P nonlinear:0.045), and COPD risk in males. WQS analysis showed mixed PFAS exposure was correlated with COPD risk in males (OR: 1.44, 95 % CI:1.18 to 1.75, P: <0.001). Albumin mediated the relationship between PFOA and COPD (mediated proportion: -17.94 %). CONCLUSION: This study concludes PFOA and PFNA are linked to a higher COPD risk in males, and serum albumin plays a mediating role in the relationship between PFOA and COPD. Thess findings are beneficial for the prevention of COPD. Further studies are required to explore potential mechanisms.

Redox-modulated SNX25 as a novel regulator of GPCR-G protein signaling from endosomes.

GPCR-G protein signaling from endosomes plays a crucial role in various physiological and pathological processes. However, the mechanism by which endosomal G protein signaling is terminated remains largely unknown. In this study, we aimed to investigate the regulatory mechanisms involved in terminating the signaling of Gα subunits from endosomes. Through structural analysis and cell-based assays, we have discovered that SNX25, a protein that targets endosomes via its PXA or PXC domain, interacts with regulator of G protein signaling (RGS) proteins (including RGS2, RGS4, RGS8, and RGS17) in a redox-regulated manner. The interaction between SNX25 and these RGS proteins enhances their GTPase-accelerating activity towards Gαi/q and their ability to bind GDP-bound (inactive form) Gαi/q. As a result, SNX25 recruits these RGS proteins to endosomes, leading to the termination of endosomal Gαi/q signaling. Furthermore, we have found that the SNX25/RGS complex also exerts a negative regulatory effect on Gαi/q signaling from the plasma membrane. This is achieved by recruiting Gαi/q to endosomes and preventing its activation on the plasma membrane. Our findings shed light on the previously unknown role of redox-modulated SNX25 in inhibiting Gαi/q signaling, thereby uncovering a novel mechanism for terminating Gαi/q signaling from endosomes. Importantly, this study expands our understanding of the regulation of GPCR-Gαi/q signaling beyond the plasma membrane.

Heavy metal induced shifts in microbial community composition and interactions with dissolved organic matter in coastal sediments.

Heavy metals can impact the structure and function of coastal sediment. The dissolved organic matter (DOM) pool plays an important role in determining both the heavy metal toxicity and microbial community composition in coastal sediments. However, how heavy metals affect the interactions between microbial communities and DOM remains unclear. Here, we investigated the influence of heavy metals on the microbial community structure (including bacteria and archaea) and DOM composition in surface sediments of Beibu Gulf, China. Our results revealed firstly that chromium, zinc, cadmium, and lead were the heavy metals contributing to pollution in our studied area. Furthermore, the DOM chemical composition was distinctly different in the contaminated area from the uncontaminated area, characterized by a higher average O/C ratio and increased prevalence of carboxyl-rich alicyclic molecules (CRAM) and highly unsaturated compounds (HUC). This indicates that DOM in the contaminated area was more recalcitrant compared to the uncontaminated area. Except for differences in archaeal diversity between the two areas, there were no significant variations observed in the structure of archaea and bacteria, as well as the diversity of bacteria, across the two areas. Nevertheless, our co-occurrence network analysis revealed that the B2M28 and Euryarchaeota, dominating bacterial and archaeal groups in the contaminated area were strongly related to CRAM. The network analysis also unveiled correlations between active bacteria and elevated proportions of nitrogen-containing DOM molecules. In contrast, the archaea-DOM network exhibited strong associations with nitrogen- and sulfur-containing molecules. Collectively, these findings suggest that heavy metals indeed influence the interaction between microbial communities and DOM, potentially affecting the accumulation of recalcitrant compounds in coastal sediments.

Preclinical evaluation of the SARS-CoV-2 Mpro inhibitor RAY1216 shows improved pharmacokinetics compared with nirmatrelvir.

Although vaccines are available for SARS-CoV-2, antiviral drugs such as nirmatrelvir are still needed, particularly for individuals in whom vaccines are less effective, such as the immunocompromised, to prevent severe COVID-19. Here we report an α-ketoamide-based peptidomimetic inhibitor of the SARS-CoV-2 main protease (Mpro), designated RAY1216. Enzyme inhibition kinetic analysis shows that RAY1216 has an inhibition constant of 8.4 nM and suggests that it dissociates about 12 times slower from Mpro compared with nirmatrelvir. The crystal structure of the SARS-CoV-2 Mpro:RAY1216 complex shows that RAY1216 covalently binds to the catalytic Cys145 through the α-ketoamide group. In vitro and using human ACE2 transgenic mouse models, RAY1216 shows antiviral activities against SARS-CoV-2 variants comparable to those of nirmatrelvir. It also shows improved pharmacokinetics in mice and rats, suggesting that RAY1216 could be used without ritonavir, which is co-administered with nirmatrelvir. RAY1216 has been approved as a single-component drug named 'leritrelvir' for COVID-19 treatment in China.