The global regulation of c-di-GMP and cAMP in bacteria.

Nucleotide second messengers are highly versatile signaling molecules that regulate a variety of key biological processes in bacteria. The best-studied examples are cyclic AMP (cAMP) and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which both act as global regulators. Global regulatory frameworks of c-di-GMP and cAMP in bacteria show several parallels but also significant variances. In this review, we illustrate the global regulatory models of the two nucleotide second messengers, compare the different regulatory frameworks between c-di-GMP and cAMP, and discuss the mechanisms and physiological significance of cross-regulation between c-di-GMP and cAMP. c-di-GMP responds to numerous signals dependent on a great number of metabolic enzymes, and it regulates various signal transduction pathways through its huge number of effectors with varying activities. In contrast, due to the limited quantity, the cAMP metabolic enzymes and its major effector are regulated at different levels by diverse signals. cAMP performs its global regulatory function primarily by controlling the transcription of a large number of genes via cAMP receptor protein (CRP) in most bacteria. This review can help us understand how bacteria use the two typical nucleotide second messengers to effectively coordinate and integrate various physiological processes, providing theoretical guidelines for future research.

Silver(I) Complexes with Mefenamic Acid and Nitrogen Heterocyclic Ligands: Synthesis, Characterization, and Biological Evaluation.

Four Ag(I) complexes with mefenamato and nitrogen heterocyclic ligands, [Ag(2-apy)(mef)]2 (1), [Ag(3-apy)(mef)] (2), [Ag2(tmpyz)(mef)2] (3), and {[Ag(4,4'-bipy)(mef)]2(CH3CN)1.5(H2O)2}n (4), (mef = mefenamato, 2-apy = 2-aminopyridine, 3-apy = 3-aminopyridine, tmpyz = 2,3,5,6-tetramethylpyrazine, 4,4'-bipy = 4,4'-bipyridine), were synthesized and characterized. The interactions of these complexes with BSA were investigated by fluorescence spectroscopy, which indicated that these complexes quench the fluorescence of BSA by a static mechanism. The fluorescence data also indicated that the complexes showed good affinity for BSA, and one binding site on BSA was suitable for the complexes. The in vitro cytotoxicity of the four complexes against human cancer cell lines (MCF-7, HepG-2, A549, and MDA-MB-468) and one normal cell line (HTR-8) was evaluated by the MTT assay. Complex 1 displayed high cytotoxic activity against A549 cells. Further studies revealed that complex 1 could enhance the intracellular levels of ROS (reactive oxygen species) in A549 cells, cause cell cycle arrest in the G0/G1 phase, and induce apoptosis in A549 cells in a dose-dependent manner.

Data-driven online prediction of remaining fatigue life of a steel plate based on nonlinear ultrasonic monitoring.

Online monitoring fatigue damage and remaining fatigue life (RFL) prediction of engineering structures are essential to ensure safety and reliability. A data-driven online prediction method based on nonlinear ultrasonic monitoring was developed to predict the RFL of the structures in real-time. Nonlinear ultrasonic parameters were obtained to monitoring the fatigue degradation. A Bayesian framework was employed to continuously compute and update the RFL distributions of the structures. Nonlinear ultrasonic experiments were performed on the fatigue damaged Q460 steel to validate the developed prediction methodology. The result indicates that the developed method has high prediction accuracy and can provide effective information for subsequent decision-making.

Sustainable double-synergistic silver-hydroxyapatite composite catalyst derived from fish bones for efficient disinfection of Vibrio parahaemolyticus.

Vibrio parahaemolyticus is a food-borne pathogen that poses a serious threat to seafood safety and human health. An efficient, nontoxic, and sustainable disinfection material with a stable structure is urgently needed. Herein, silver (Ag)-hydroxyapatite (HAP) composite catalysts were prepared using HAP derived from waste fish bones. The Ag2.50%-HAP showed a 100% disinfection rate against V. parahaemolyticus, disinfecting nearly 7.0 lg CFU mL-1 within 15 min at a low concentration of 300 µg mL-1. This efficient disinfection activity could be attributed to the double-synergistic effect of Ag and superoxide radicals, which resulted in the destruction of bacterial cell structures and the leakage of intracellular proteins. Importantly, the composite also exhibited high activity in controlling the growth of pathogens during the storage process of Penaeus vannamei. These findings provided sustainable composite catalysts for disinfecting V. parahaemolyticus in seafood and a high-value utilization strategy for waste fish bones.

Time-Released Black Phosphorus Hydrogel Accelerates Myocardial Repairing through Antioxidant and Motivates Macrophage Polarization Properties.

The improvement of the myocardial microenvironment largely determines the prognosis of myocardial infarction (MI). After MI, early removal of excessive reactive oxygen species (ROS) in the microenvironment can alleviate oxidative stress injury and promote M2 phenotype polarization of macrophages, which is important for advocating myocardial repair. In this study, we combined traditional natural hydrogel materials chitosan (CS) and gelatin (Gel) to encapsulate polydopamine-modified black phosphorus nanosheets (BP@PDA). We designed an injectable composite gel (CS-Gel-BP@PDA) with a time-released ability to achieve in situ sustained-release BP@PDA in the area of MI. Utilizing the inflammation inhibition ability of CS-Gel itself and the high reactive activity of BP@PDA with ROS, continuous improvement of infarct microenvironment and myocardial repair were achieved. The studies in vivo revealed that, compared with the saline group, CS-Gel-BP@PDA group had alleviated myocardial fibrosis and infarct size and importantly improved cardiac function. Immunofluorescence results showed that the ROS level and inflammatory response in the microenvironment of the CS-Gel-BP@PDA group were decreased. In conclusion, our study demonstrated the time-released ability, antioxidative stress activity and macrophage polarization modulation of the novel composite hydrogel CS-Gel-BP@PDA, which provides inspiration for novel therapeutic modalities for MI.

The causal relationship between sarcoidosis and autoimmune diseases: a bidirectional Mendelian randomization study in FinnGen.

Background: Sarcoidosis has been considered to be associated with many autoimmune diseases (ADs), but the cause-and-effect relationship between these two diseases has not been fully explored. Therefore, the objective of this study is to explore the possible genetic association between sarcoidosis and ADs. Methods: We conducted a bidirectional Mendelian randomization (MR) study using genetic variants associated with ADs and sarcoidosis (4,041 cases and 371,255 controls) from the FinnGen study. The ADs dataset comprised 96,150 cases and 281,127 controls, encompassing 44 distinct types of autoimmune-related diseases. Subsequently, we identified seven diseases within the ADs dataset with a case size exceeding 3,500 and performed subgroup analyses on these specific diseases. Results: The MR evidence supported the causal association of genetic predictors of ADs with an increased risk of sarcoidosis (OR = 1.79, 95% CI = 1.59 to 2.02, P IVW-FE = 1.01 × 10-21), and no reverse causation (OR = 1.05, 95% CI 0.99 to 1.12, P IVW-MRE = 9.88 × 10-2). Furthermore, subgroup analyses indicated that genetic predictors of type 1 diabetes mellitus (T1DM), celiac disease, and inflammatory bowel disease (IBD) were causally linked to an elevated risk of sarcoidosis (All P < 6.25 × 10-3). Conversely, genetic predictors of sarcoidosis showed causal associations with a higher risk of type 1 diabetes mellitus (P < 6.25 × 10-3). Conclusion: The present study established a positive causal relationship between genetic predictors of ADs (e.g. T1DM, celiac disease, and IBD) and the risk of sarcoidosis, with no evidence of reverse causation.

Dietary kelp meal improves serum antioxidants, intestinal immunity, and lipid metabolism in hybrid snakehead (Channa maculata ♀ × Channa argus ♂).

BACKGROUND: Dietary kelp possesses a variety of useful biological qualities but does not have a toxic effect on the host. In this study, we examine how kelp dietary supplementation enhances the serum biochemistry, intestinal immunity, and metabolism of hybrid snakehead. A total of 810 juvenile hybrid snakeheads (Channa maculata ♀ × Channa argus ♂), with an initial average weight of 11.4 ± 0.15 g, were allocated randomly to three treatment groups (three replicates per group). The fish were fed for 60 days with isonitrogenous and isolipidic diets. The groups were the control group (C) (20% high-gluten flour), the medium replacement group (MR) (10% high-gluten flour and 10% kelp meal), and the full replacement group (FR) (0% high-gluten flour and 15% kelp meal). RESULTS: The results showed that dietary kelp increased the activity of serum antioxidant enzymes significantly and decreased the content of serum malondialdehyde (MDA) in hybrid snakeheads, with significant changes in the FR group (P < 0.05). The intestinal morphology results showed that dietary kelp helped to increase the specific surface area of intestinal villi, which was beneficial for intestinal digestion and absorption. According to transcriptome and quantitative real-time polymerase chain reaction (qRT-PCR) analysis, dietary kelp can improve the expression of intestinal immunity and metabolism-related pathways. Among them, immune-related genes MHC1 and HSPA1 were significantly up-regulated, and IGH, MHC2, and IL-8 were significantly down-regulated (P < 0.05). Lipid metabolism-related genes DGAT2, FABP2, RXRα, and PLPP1 were all significantly up-regulated (P < 0.05). CONCLUSION: Dietary kelp can effectively improve the antioxidant function of hybrid snakeheads, improve intestinal morphology, reduce intestinal inflammation, and promote intestinal lipid synthesis and transportation, thereby improving intestinal immunity and metabolic functions. © 2024 Society of Chemical Industry.

Sestrin2 Protects Human Lens Epithelial Cells (HLECs) Against Apoptosis in Cataracts Formation: Interaction Between Endoplasmic Reticulum (ER) Stress and Oxidative Stress (OS) is Involved.

PURPOSE: To explore the correlation of endoplasmic reticulum stress (ERS) and oxidative stress (OS), and the protective effect of Sestrin2 (SESN2) on human lens epithelial cells (HLECs). METHODS: Tunicamycin (TM) was used to induce ERS in HLECs. 4-Phenylbutyric acid (4-PBA) was used to inhibit ERS. Eupatilin applied to HLECs as SESN2 agonist. SESN2 expression was knocked down via si-RNA in HLECs. The morphological changes of HLECs were observed by microscope. ER-tracker to evaluate ERS, ROS production assay to measure ROS, flow cytometry to calculate cell apoptosis rate. Immunofluorescence to observe Nrf2 translocation, and effects of TM or EUP on SESN2. Western blot and qPCR were used to evaluate the expression of GRP78, PERK, ATF4, CHOP, Nrf2, and SESN2 expression in HLECs with different treatment groups. RESULTS: ERS can elevate the expression of ROS and Nrf2 to induce OS. Upregulation of SESN2 was observed in ERS-mediate OS. Overexpression of SESN2 can reduce the overexpression of ERS-related protein GRP78, PERK, ATF4, proapoptotic protein CHOP, OS-related protein Nrf2, as well as ROS, and alleviate ERS injury at the same time. Whereas knockdown of SESN2 can upregulate the expression of GRP78, PERK, ATF4, CHOP, Nrf2, ROS, and deteriorate ERS damage. CONCLUSIONS: ERS can induce OS, they form a vicious cycle to induce apoptosis in HLECs, which may contribute to cataract formation. SESN2 could protect HLECs against the apoptosis by regulating the vicious cycle between ERS and OS.

E-M349E and NS2A/2B-P1(T) are compensatory mutations of rDTMUV-NS2AB-P1P1'(AA), which regain virus proliferation by enhancing the virus package and restoring NS2A/2B cleavage.

Duck Tembusu virus (DTMUV) belongs to the Flaviviridae family and mainly infects ducks. The genome of DTMUV is translated into a polyprotein, which is further cleaved into several protein by viral NS2B3 protease and host proteases. Crucially, the cleavage of the NS2A/2B precursor during this process is essential for the formation of replication complexes and viral packaging. Previous research has demonstrated that alanine mutations in NS2A/2B (P1P1' (AA)) result in an attenuated strain (rDTMUV-NS2A/2B-P1P1' (AA)) by disrupting NS2A/2B cleavage. In this study, we investigate the effects of the P1P1' (AA) mutation on the viral life cycle and explore compensatory mutations in rDTMUV-NS2A/2B-P1P1' (AA). Infected ducklings exhibit similar body weight gain and viral tissue loads to DTMUV-WT. Compensatory mutations E-M349E and P1(T) emerge, restoring proliferation levels to those of rDTMUV-WT. Specifically, E-M349E enhances viral packaging, while P1(T) reinstates NS2A/2B proteolysis in vitro. Thus, our findings reveal novel compensatory sites capable of restoring the attenuated DTMUV during polyprotein cleavage and packaging.

HSP70 positively regulates translation by interacting with the IRES and stabilizes the viral structural proteins VP1 and VP3 to facilitate duck hepatitis A virus type 1 replication.

The maintenance of viral protein homeostasis depends on the interaction between host cell proteins and viral proteins. As a molecular chaperone, heat shock protein 70 (HSP70) has been shown to play an important role in viral infection. Our results showed that HSP70 can affect translation, replication, assembly, and release during the life cycle of duck hepatitis A virus type 1 (DHAV-1). We demonstrated that HSP70 can regulate viral translation by interacting with the DHAV-1 internal ribosome entry site (IRES). In addition, HSP70 interacts with the viral capsid proteins VP1 and VP3 and promotes their stability by inhibiting proteasomal degradation, thereby facilitating the assembly of DHAV-1 virions. This study demonstrates the specific role of HSP70 in regulating DHAV-1 replication, which are helpful for understanding the pathogenesis of DHAV-1 infection and provide additional information about the role of HSP70 in infection by different kinds of picornaviruses, as well as the interaction between picornaviruses and host cells.

Prognostic value of postoperative anti-thyroglobulin antibody in patients with differentiated thyroid cancer.

Purpose: Postoperative thyroglobulin (Tg) generally serves as a biomarker to monitor the recurrence or persistence of differentiated thyroid cancer (DTC), whereas it constrains to interference from anti-thyroglobulin antibody (TgAb). This study aimed to determine the value of postoperative TgAb as a surrogate for monitoring tumor status in DTCs with positive TgAb after successful radioactive iodine (RAI) remnant ablation. Methods: We retrospectively enrolled DTC patients with positive (≥40 IU/mL, Roche) postoperative TgAb measurements. An index of TgAb change (ΔTgAb) was defined to describe the TgAb decrease rate. DTC status was defined as either no evidence of disease (NED) or persistent/recurrent disease (PRD). Univariate and multivariate binary logistic analyses were used to identify the independent risk factors of PRD. Receiver operating characteristic (ROC) curves were performed to determine the optimal cutoff values of each risk factor, and DeLong's test was conducted to compare their predictive powers. Kaplan-Meier curves were used to assess the impact of different TgAb trends in the first year on progression-free survival. Results: Of the 232 patients enrolled, the median diagnosis age was 34 years (range, 18-62 years), with a male-to-female ratio of 1:4.66 (41/191). Among them, after a median follow-up of 44 months (range, 4-128 months),183 (78.87%) patients were evaluated as NED, while the other 49 (21.12%) had either persistent (n = 25) or recurrent disease (n = 24). Multivariate regression showed that ΔTgAb (P < 0.001) and lymph node metastasis (LNM) rate (P = 0.009) were independently relevant to the presence of PRD, with optimal cutoff values of 47.0% and 35.1%, respectively. It is important to note that there is a high negative predictive value (96.93%) of ΔTgAb with the cutoff of 47.0%. DeLong's test showed that ΔTgAb alone and the combination of ΔTgAb and LNM rate were significantly greater than the isolated LNM rate (both P < 0.001) in predicting NED, while there was no statistical difference of the predictive power between ΔTgAb and the combination (P = 0.203). Additionally, patients with ΔTgAb >47.0% had longer progression-free survival than those with ΔTgAb ≤47.0% (not reached vs. 50 months, P < 0.001), and those with ΔTgAb >47.0% or negative conversion within the first year after RAI ablation had longer progression-free survival. Conclusion: Our study suggested that ΔTgAb could serve as a valuable indicator of disease status in DTC patients with positive TgAb. A ΔTgAb of >47.0% is conducive to identify those with NED and may help to obviate their overtreatment. The decrease rate and negative conversion of TgAb in the first year were good predictors of disease-free survival in patients.

Hapten synthesis, monoclonal antibody production and immunoassay development for analyzing spiropidion residues.

Spiropidion developed by Syngenta shows high insecticidal and acaricidal activity against a wide range of sucking pests. In this study, according to the structure of spiropidion, two haptens were synthesized by introducing carboxyl groups from the ester group. After cell fusion, a monoclonal antibody (mAb 8B5) of spiropidion was obtained. The IC50 of the established heterologous indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was 7.36 ng/mL, and its working range was 1.75-34.92 ng/mL. The average recoveries were 76.05-124.78% in the Yangtze River and citrus samples. Moreover, the ic-ELISA results of 15 citrus samples agreed well with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Overall, the established ic-ELISA could be applied for the spiropidion residue monitor in food and agricultural samples.

Integrative and conjugative elements of Pasteurella multocida: Prevalence and signatures in population evolution.

Pasteurella multocida (P. multocida) is a bacterial pathogen responsible for a range of infections in humans and various animal hosts, causing significant economic losses in farming. Integrative and conjugative elements (ICEs) are important horizontal gene transfer elements, potentially enabling host bacteria to enhance adaptability by acquiring multiple functional genes. However, the understanding of ICEs in P. multocida and their impact on the transmission of this pathogen remains limited. In this study, 42 poultry-sourced P. multocida genomes obtained by high-throughput sequencing together with 393 publicly available P. multocida genomes were used to analyse the horizontal transfer of ICEs. Eighty-two ICEs were identified in P. multocida, including SXT/R391 and Tn916 subtypes, as well as three subtypes of ICEHin1056 family, with the latter being widely prevalent in P. multocida and carrying multiple resistance genes. The correlations between insertion sequences and resistant genes in ICEs were also identified, and some ICEs introduced the carbapenem gene blaOXA-2 and the bleomycin gene bleO to P. multocida. Phylogenetic and collinearity analyses of these bioinformatics found that ICEs in P. multocida were transmitted vertically and horizontally and have evolved with host specialization. These findings provide insight into the transmission and evolution mode of ICEs in P. multocida and highlight the importance of understanding these elements for controlling the spread of antibiotic resistance.

Effect of LncRNA LOC106505926 on myogenesis and Lipogenesis of porcine primary cells.

BACKGROUND: Skeletal muscle development and fat deposition have important effects on meat quality. The study of regulating skeletal muscle development and fat deposition is of great significance in improving the quality of carcass and meat. In the present study, whole transcriptome sequencing (including RNA-Seq and miRNA-Seq) was performed on the longissimus dorsi muscle (LDM) of Jinfen White pigs at 1, 90, and 180 days of age. RESULTS: The results showed that a total of 245 differentially expressed miRNAs were screened in any two comparisons, which may be involved in the regulation of myogenesis. Among them, compared with 1-day-old group, miR-22-5p was significantly up-regulated in 90-day-old group and 180-day-old group. Functional studies demonstrated that miR-22-5p inhibited the proliferation and differentiation of porcine skeletal muscle satellite cells (PSCs). Pearson correlation coefficient analysis showed that long non-coding RNA (lncRNA) LOC106505926 and CXXC5 gene had strong negative correlations with miR-22-5p. The LOC106505926 and CXXC5 were proven to promote the proliferation and differentiation of PSCs, as opposed to miR-22-5p. In terms of mechanism, LOC106505926 functions as a molecular sponge of miR-22-5p to modulate the expression of CXXC5, thereby inhibits the differentiation of PSCs. In addition, LOC106505926 regulates the differentiation of porcine preadipocytes through direct binding with FASN. CONCLUSIONS: Collectively, our results highlight the multifaceted regulatory role of LOC106505926 in controlling skeletal muscle and adipose tissue development in pigs and provide new targets for improving the quality of livestock products by regulating skeletal muscle development and fat deposition.

Multiple functions of the nonstructural protein 3D in picornavirus infection.

3D polymerase, also known as RNA-dependent RNA polymerase, is encoded by all known picornaviruses, and their structures are highly conserved. In the process of picornavirus replication, 3D polymerase facilitates the assembly of replication complexes and directly catalyzes the synthesis of viral RNA. The nuclear localization signal carried by picornavirus 3D polymerase, combined with its ability to interact with other viral proteins, viral RNA and cellular proteins, indicate that its noncatalytic role is equally important in viral infections. Recent studies have shown that 3D polymerase has multiple effects on host cell biological functions, including inducing cell cycle arrest, regulating host cell translation, inducing autophagy, evading immune responses, and triggering inflammasome formation. Thus, 3D polymerase would be a very valuable target for the development of antiviral therapies. This review summarizes current studies on the structure of 3D polymerase and its regulation of host cell responses, thereby improving the understanding of picornavirus-mediated pathogenesis caused by 3D polymerase.

Inflammation mediates the association between furan exposure and the prevalence and mortality of chronic obstructive pulmonary disease: National Health and Nutrition Examination Survey 2013-2018.

BACKGROUND: Although extensive research has established associations between chronic obstructive pulmonary disease (COPD) and environmental pollutants, the connection between furan and COPD remains unclear. This study aimed to explore the association between furan and COPD while investigating potential mechanisms. METHODS: The study involved 7,482 adults from the National Health and Nutrition Examination Survey 2013-2018. Exposure to furan was assessed using blood furan levels. Participants were categorized into five groups based on quartiles of log10-transformed blood furan levels. Logistic regression and restricted cubic spline regression models were used to assess the association between furan exposure and COPD risk. Mediating analysis was performed to assess the contribution of inflammation to the effects of furan exposure on COPD prevalence. Cox regression was used to assess the association between furan exposure and the prognosis of COPD. RESULTS: Participants with COPD exhibited higher blood furan levels compared to those without COPD (P < 0.001). Log10-transformed blood furan levels were independently associated with an increased COPD risk after adjusting for all covariates (Q5 vs. Q1: OR = 4.47, 95% CI = 1.58-12.66, P = 0.006, P for trend = 0.001). Inflammatory cells such as monocytes, neutrophils, and basophils were identified as mediators in the relationship between furan exposure and COPD prevalence, with mediated proportions of 8.73%, 20.90%, and 10.94%, respectively (all P < 0.05). Moreover, multivariate Cox regression analysis revealed a positive correlation between log10-transformed blood furan levels and respiratory mortality in COPD patients (HR = 41.00, 95% CI = 3.70-460.00, P = 0.003). CONCLUSIONS: Exposure to furan demonstrates a positive correlation with both the prevalence and respiratory mortality of COPD, with inflammation identified as a crucial mediator in this relationship.

Solvent-Mediated Hetero/Homo-Phase Crystallization of Copper Nanoclusters and Superatomic Kernel-Related NIR Phosphorescence.

Atomically precise superatomic copper nanoclusters (Cu NCs) have been the subject of immense interest for their intriguing structures and diverse properties; nonetheless, the variable oxidation state of copper ions and complex solvation effects in wet synthesis systems pose significant challenges for comprehending their synthesis and crystallization mechanism. Herein, we present a solvent-mediated approach for the synthesis of two Cu NCs, namely, superatomic Cu26 and pure-Cu(I) Cu16. They initially formed as a hetero-phase and then separated as a homo-phase via modulating binary solvent composition. In situ UV/vis absorption and electrospray ionization mass spectra revealed that the solvent-mediated assembly was determined to be the underlying mechanism of hetero/homo-phase crystallization. Cu26 is a 2-electron superatom with a kernel-shell structure that includes a [Cu20Se12]4- shell and [Cu6]4+ kernel, containing two 1S jellium electrons. Conversely, Cu16 is a pure-Cu(I) Cu/Se nanocluster that features a [Cu16Se6]4+ core protected by extra dimercaptomaleonitrile ligands. Remarkably, Cu26 exhibits unique near-infrared phosphorescence (NIR PH) at 933 nm due to the presence of a superatomic kernel-related charge transfer state (3MM(Cu)CT). Overall, this work not only showcases the hetero/homo-phase crystallization of Cu NCs driven by a solvent-mediated assembly mechanism but also enables the rare occurrence of NIR PH within the 2-electron copper superatom family.

The topological model of NS4B and its TMD3 in duck TMUV proliferation.

Duck Tembusu virus (DTMUV) belongs to the Flaviviridae family and mainly infects ducks. Duck Tembusu virus genome encodes one polyprotein that undergoes cleavage to produce 10 proteins. Among these, NS4B, the largest transmembrane protein, plays a crucial role in the viral life cycle. In this study, we investigated the localization of NS4B and found that it is located in the endoplasmic reticulum, where it co-localizes with DTMUV dsRNA. Subsequently, we confirmed 5 different transmembrane domains of NS4B and discovered that only its transmembrane domain 3 (TMD3) can traverse ER membrane. Then mutations were introduced in the conserved amino acids of NS4B TMD3 of DTMUV replicon and infectious clone. The results showed that V111G, V117G, and I118G mutations enhanced viral RNA replication, while Q104A, T106A, A113L, M116A, H120A, Y121A, and A122G mutations reduced viral replication. Recombinant viruses with these mutations were rescued and studied in BHK21 cells. The findings demonstrated that A113L and H120A mutations led to higher viral titers than the wild-type strain, while Q104A, T106A, V111G, V117G, and Y121A mutations attenuated viral proliferation. Additionally, H120A, M116A, and A122G mutations enhanced viral proliferation. Furthermore, Q104A, T106A, V111G, M116A, V117G, Y121A, and A122G mutants showed reduced viral virulence to 10-d duck embryos. Animal experiments further indicated that all mutation viruses resulted in lower genome copy numbers in the spleen compared to the WT group 5 days postinfection. Our data provide insights into the topological model of DTMUV NS4B, highlighting the essential role of NS4B TMD3 in viral replication and proliferation.

Temperature-Controlled Selective Formation of Silver Nanoclusters and Their Transformation to the Same Product.

Herein, two atomically precise silver nanoclusters, Ag54 and Ag33, directed by inner anion templates (CrO4 2- and/or Cl-), are initially isolated as a mixed phase from identical reactants across a wide temperature range (20-80 °C). Interestingly, fine-tuning the reaction temperature can realize pure phase synthesis of the two nanoclusters; that is, a metastable Ag54 is kinetically formed at a low temperature (20 °C), whereas such a system is steered towards a thermodynamically stable Ag33 at a relatively high temperature (80 °C). Electrospray ionization mass spectrometry illustrates that the stability of Ag33 is superior to that of Ag54, which is further supported by density functional theory calculations. Importantly, the difference in structural stability can influence the pathway of 1,4-bis(pyrid-4-yl)benzene induced transformation reaction starting from Ag54 and Ag33. The former undergoes a dramatic breakage-reorganization process to form an Ag31 dimer (Ag31), while the same product can be also achieved from the latter following a noninvasive ligand exchange process. Both the Ag54 and Ag33 have the potential for further remote laser ignition applications. This work not only demonstrates how temperature controls the isolation of a specific phase, but also sheds light on the structural transformation pathway of nanoclusters with different stability.

Synergistic large segmental bone repair by 3D printed bionic scaffolds and engineered ADSC nanovesicles: Towards an optimized regenerative microenvironment.

Achieving sufficient bone regeneration in large segmental defects is challenging, with the structure of bone repair scaffolds and their loaded bioactive substances crucial for modulating the local osteogenic microenvironment. This study utilized digital laser processing (DLP)-based 3D printing technology to successfully fabricate high-precision methacryloylated polycaprolactone (PCLMA) bionic bone scaffold structures. Adipose-derived stem cell-engineered nanovesicles (ADSC-ENs) were uniformly and stably modified onto the bionic scaffold surface using a perfusion device, constructing a conducive microenvironment for tissue regeneration and long bone defect repair through the scaffold's structural design and the vesicles' biological functions. Scanning electron microscopy (SEM) examination of the scaffold surface confirmed the efficient loading of ADSC-ENs. The material group loaded with vesicles (PCLMA-BAS-ENs) demonstrated good cell compatibility and osteogenic potential when analyzed for the adhesion and osteogenesis of primary rabbit bone marrow mesenchymal stem cells (BMSCs) on the material surface. Tested in a 15 mm critical rabbit radial defect model, the PCLMA-BAS-ENs scaffold facilitated near-complete bone defect repair after 12 weeks. Immunofluorescence and proteomic results indicated that the PCLMA-BAS-ENs scaffold significantly improved the osteogenic microenvironment at the defect site in vivo, promoted angiogenesis, and enhanced the polarization of macrophages towards M2 phenotype, and facilitated the recruitment of BMSCs. Thus, the PCLMA-BAS-ENs scaffold was proven to significantly promote the repair of large segmental bone defects. Overall, this strategy of combining engineered vesicles with highly biomimetic scaffolds to promote large-segment bone tissue regeneration holds great potential in orthopedic and other regenerative medicine applications.