A cheaper substitute for HRP: ultra-small Cu-Au bimetallic enzyme mimics with infinitesimal steric hindrance to promote catalytic lateral flow immunodetection of clenbuterol.

A highly sensitive lateral flow immunoassay (LFIA) is developed for the enzyme-catalyzed and double-reading determination of clenbuterol (CLE), in which a new type of probe was adopted through the direct electrostatic adsorption of ultra-small copper-gold bimetallic enzyme mimics (USCGs) and monoclonal antibodies. In the assay, based on the peroxidase activity of USCG, the chromogenic substrate TMB-H2O2 was introduced to trigger its color development, and the results were compared with those before catalysis. The detection sensitivity after catalysis is 0.03 ng mL-1 under optimal circumstances, which is 6-fold better than that of the traditional Au NPs-based LFIA and 2-fold greater than that before catalysis. This approach was successfully applied to the detection of CLE in milk, pork and mutton samples with an optimum assay time of 7 min and best catalytic time of 80 s, after which satisfactory recoveries of 98.53-117.79% were obtained. Cu-Au nanoparticles as a signal tag and the use of their nanozyme properties are the first applications in the field of LFIA. This work can be a promising exhibition for the application of a cheaper substitute for HRP, ultra-small bimetallic enzyme mimics, in LFIAs.

Mapping the global distribution of C4 vegetation using observations and optimality theory.

Plants with the C4 photosynthesis pathway typically respond to climate change differently from more common C3-type plants, due to their distinct anatomical and biochemical characteristics. These different responses are expected to drive changes in global C4 and C3 vegetation distributions. However, current C4 vegetation distribution models may not predict this response as they do not capture multiple interacting factors and often lack observational constraints. Here, we used global observations of plant photosynthetic pathways, satellite remote sensing, and photosynthetic optimality theory to produce an observation-constrained global map of C4 vegetation. We find that global C4 vegetation coverage decreased from 17.7% to 17.1% of the land surface during 2001 to 2019. This was the net result of a reduction in C4 natural grass cover due to elevated CO2 favoring C3-type photosynthesis, and an increase in C4 crop cover, mainly from corn (maize) expansion. Using an emergent constraint approach, we estimated that C4 vegetation contributed 19.5% of global photosynthetic carbon assimilation, a value within the range of previous estimates (18-23%) but higher than the ensemble mean of dynamic global vegetation models (14 ± 13%; mean ± one standard deviation). Our study sheds insight on the critical and underappreciated role of C4 plants in the contemporary global carbon cycle.

Silica-induced macrophage pyroptosis propels pulmonary fibrosis through coordinated activation of relaxin and osteoclast differentiation signaling to reprogram fibroblasts.

Silica nanoparticle (SiNP) exposure induces severe pulmonary inflammation and fibrosis, but the pathogenesis remains unclear, and effective therapies are currently lacking. To explore the mechanism underlying SiNPs-induced pulmonary fibrosis, we constructed in vivo silica exposure animal models and in vitro models of silica-induced macrophage pyroptosis and fibroblast transdifferentiation. We found that SiNP exposure elicits upregulation of pulmonary proteins associated with pyroptosis, including NLRP3, ASC, IL-1ß, and GSDMD, while the immunofluorescence staining co-localized NLRP3 and GSDMD with macrophage-specific biomarker F4/80 in silica-exposed lung tissues. However, the NLRP3 inhibitor MCC950 and classical anti-fibrosis drug pirfenidone (PFD) were found to be able to alleviate silica-induced collagen deposition in the lungs. In in vitro studies, we exposed the fibroblast to a conditioned medium from silica-induced pyroptotic macrophages and found enhanced expression of α-SMA, suggesting increased transdifferentiation of fibroblast to myofibroblast. In line with in vivo studies, the combined treatment of MCC950 and PFD was demonstrated to inhibit the expression of α-SMA and attenuate fibroblast transdifferentiation. Mechanistically, we adopted high throughput RNA sequencing on fibroblast with different treatments and found activated signaling of relaxin and osteoclast differentiation pathways, where the expression of the dysregulated genes in these two pathways was examined and found to be consistently altered both in vitro and in vivo. Collectively, our study demonstrates that SiNP exposure induces macrophage pyroptosis, which subsequently causes fibroblast transdifferentiation to myofibroblasts, in which the relaxin and osteoclast differentiation signaling pathways play crucial roles. These findings may provide valuable references for developing new therapies for pulmonary fibrosis.

Delayed Enhancement of Intracranial Atherosclerotic Plaque Can Better Differentiate Culprit Lesions: A Multiphase Contrast-Enhanced Vessel Wall MRI Study.

BACKGROUND AND PURPOSE: Intracranial plaque enhancement (IPE) identified by contrast-enhanced vessel wall MR imaging (VW-MR imaging) is an emerging marker of plaque instability related to stroke risk, but there was no standardized timing for postcontrast acquisition. We aim to explore the optimal postcontrast timing by using multiphase contrast-enhanced VW-MR imaging and to test its performance in differentiating culprit and nonculprit lesions. MATERIALS AND METHODS: Patients with acute ischemic stroke due to intracranial plaque were prospectively recruited to undergo VW-MR imaging with 1 precontrast phase and 4 consecutive postcontrast phases (9 minutes and 13 seconds for each phase). The signal intensity (SI) values of the CSF and intracranial plaque were measured on 1 precontrast and 4 postcontrast phases to determine the intracranial plaque enhancement index (PEI). The dynamic changes of the PEI were compared between culprit and nonculprit plaques on the postcontrast acquisitions. RESULTS: Thirty patients with acute stroke (aged 59 ± 10 years, 18 [60%] men) with 113 intracranial plaques were included. The average PEI of all intracranial plaques significantly increased (up to 14%) over the 4 phases. There was significantly increased PEI over the 4 phases for culprit plaques (an average increase of 23%), but this was not observed for nonculprit plaques. For differentiating culprit and nonculprit plaques, we observed that the performance of IPE in the second postcontrast phase (cutoff = 0.83, AUC = 0.829 [0.746-0.893]) exhibited superior accuracy when compared with PEI in the first postcontrast phase (cutoff = 0.48; AUC = 0.768 [0.680-0.843]) (P = .022). CONCLUSIONS: A 9-minute delay of postcontrast acquisition can maximize plaque enhancement and better differentiate between culprit and nonculprit plaques. In addition, culprit and nonculprit plaques have different enhancement temporal patterns, which should be evaluated in future studies.

Depressive symptoms over time among survivors after critical illness: A systematic review and meta-analysis.

OBJECTIVE: Critical illness survivors frequently experience various degrees of depressive symptoms, which hinder their recovery and return to daily life. However, substantial variability in the prevalence of depressive symptoms has been reported among critical illness survivors. The exact prevalence remains uncertain. METHODS: A systematic search was performed in PubMed, Embase, CINAHL, and PsycINFO from inception to August 2023 for observational studies that reported depressive symptoms in adult critical illness survivors. The random-effects model was used to estimate the prevalence of depressive symptoms. Subgroup analysis and meta-regression were conducted to explore potential moderators of heterogeneity. Study quality was evaluated using the Joanna Briggs Institute's tool and the GRADE approach. RESULTS: Fifty-two studies with 24,849 participants met the inclusion criteria. Overall prevalence estimate of depressive symptoms was 21.1% (95% CI, 18.3-24.1%). The prevalence of depressive symptoms remains stable over time. Point prevalence estimates were 21.3% (95% CI, 9.9-35.4%), 19.9% (95% CI, 14.6-25.9%), 18.5% (95% CI, 9.6-29.2%), 21.0% (95% CI, 16.8-25.5%), and 22.6% (95% CI, 14.4-31.8%) at <3, 3, 6, 12, and > 12 months after discharge from intensive care unit (ICU), respectively. CONCLUSIONS: Depressive symptoms may impact 1 in 5 adult critically ill patients within 1 year or more following ICU discharge. An influx of rehabilitation service demand is expected, and risk stratification to make optimal clinical decisions is essential. More importantly, to propose measures for the prevention and improvement of depressive symptoms in patients after critical care, given the continuous, dynamic management of ICU patients, including ICU stay, transition to general wards, and post-hospital.

The global landscape of immune-derived lncRNA signature in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is a highly heterogeneous cancer. This heterogeneity has an impact on the efficacy of immunotherapy. Long noncoding RNAs (lncRNAs) have been found to play regulatory functions in cancer immunity. However, the global landscape of immune-derived lncRNA signatures has not yet been explored in colorectal cancer. METHODS: In this study, we applied DESeq2 to identify differentially expressed lncRNAs in colon cancer. Next, we performed an integrative analysis to globally identify immune-driven lncRNA markers in CRC, including immune-associated pathways, tumor immunogenomic features, tumor-infiltrating immune cells, immune checkpoints, microsatellite instability (MSI) and tumor mutation burden (TMB). RESULTS: We also identified dysregulated lncRNAs, such as LINC01354 and LINC02257, and their clinical relevance in CRC. Our findings revealed that the differentially expressed lncRNAs were closely associated with immune pathways. In addition, we found that RP11-354P11.3 and RP11-545G3.1 had the highest association with the immunogenomic signature. As a result, these signatures could serve as markers to assess immunogenomic activity in CRC. Among the immune cells, resting mast cells and M0 macrophages had the highest association with lncRNAs in CRC. The AC006129.2 gene was significantly associated with several immune checkpoints, for example, programmed cell death protein 1 (PD-1) and B and T lymphocyte attenuator (BTLA). Therefore, the AC006129.2 gene could be targeted to regulate the condition of immune cells or immune checkpoints to enhance the efficacy of immunotherapy in CRC patients. Finally, we identified 15 immune-related lncRNA-generated open reading frames (ORFs) corresponding to 15 cancer immune epitopes. CONCLUSION: In conclusion, we provided a genome-wide immune-driven lncRNA signature for CRC that might provide new insights into clinical applications and immunotherapy.

Exosomes derived from programmed cell death: mechanism and biological significance.

Exosomes are nanoscale extracellular vesicles present in bodily fluids that mediate intercellular communication by transferring bioactive molecules, thereby regulating a range of physiological and pathological processes. Exosomes can be secreted from nearly all cell types, and the biological function of exosomes is heterogeneous and depends on the donor cell type and state. Recent research has revealed that the levels of exosomes released from the endosomal system increase in cells undergoing programmed cell death. These exosomes play crucial roles in diseases, such as inflammation, tumors, and autoimmune diseases. However, there is currently a lack of systematic research on the differences in the biogenesis, secretion mechanisms, and composition of exosomes under different programmed cell death modalities. This review underscores the potential of exosomes as vital mediators of programmed cell death processes, highlighting the interconnection between exosome biosynthesis and the regulatory mechanisms governing cell death processes. Furthermore, we accentuate the prospect of leveraging exosomes for the development of innovative biomarkers and therapeutic strategies across various diseases.

Thrombospondin-1-mediated crosstalk between autophagy and oxidative stress orchestrates repair of blast lung injury.

Coal mining carries inherent risks of catastrophic gas explosions capable of inflicting severe lung injury. Using complementary in vivo and in vitro models, we explored mechanisms underlying alveolar epithelial damage and repair following a gas explosion in this study. In a rat model, the gas explosion was demonstrated to trigger inflammation and injury within the alveolar epithelium. The following scRNA-sequencing revealed that alveolar epithelial cells exhibited the most profound transcriptomic changes after gas explosion compared to other pulmonary cell types. In the L2 alveolar epithelial cells, the blast was found to cause autophagic flux by inducing autophagosome formation, LC3 lipidation, and p62 degradation. Transcriptomic profiling of the L2 cells identified PI3K-Akt and p53 pathways as critical modulators governing autophagic and oxidative stress responses to blast damage. Notably, Thrombospondin-1 (Thbs1) was determined for the first time as a pivotal node interconnecting these two pathways. The findings of this study illuminate intricate mechanisms of alveolar epithelial injury and recovery after blast trauma, highlighting autophagic and oxidative stress responses mediated by Thbs1-associated PI3K-Akt and p53 pathways as high-value therapeutic targets, and strategic modulation of these pathways in future studies may mitigate lung damage by reducing oxidative stress while engaging endogenous tissue repair processes like autophagy.

Associations between atherosclerotic luminal stenosis in the distal internal carotid artery and diffuse wall thickening in its upstream segment.

OBJECTIVES: Significant atherosclerotic stenosis or occlusion in the distal internal carotid artery (ICA) may induce diffuse wall thickening (DWT) in the upstream arterial wall. This study aimed to assess the association of atherosclerotic steno-occlusive diseases in the distal ICA with DWT in the upstream ipsilateral ICA. METHODS: Individuals with atherosclerotic stenosis in the distal ICA, detected by carotid MR vessel wall imaging using 3D pre- and post-contrast T1 volume isotropic turbo spin-echo acquisition (T1-VISTA) sequence, were enrolled. The associations of vessel wall thickening, the longitudinal extent of DWT, enhancement of the upstream ipsilateral ICA, and stenosis degree in the distal ICA were examined. RESULTS: Totally 64 arteries in 55 patients with atherosclerotic steno-occlusive distal ICAs were included. Significant correlations were found between distal ICA stenosis and DWT in the petrous ICA (r = 0.422, p = 0.001), DWT severity (r = 0.474, p < 0.001), the longitudinal extent of DWT in the ICA (r = 0.671, p < 0.001), enhancement in the petrous ICA (r = 0.409, p = 0.001), and enhancement degree (r = 0.651, p < 0.001). In addition, high degree of enhancement was correlated with both increased wall thickness and increased prevalence of DWT in the petrous ICA (both p < 0.001). CONCLUSIONS: DWT of the petrous ICA is commonly detected in patients with atherosclerotic steno-occlusive disease in the distal ICA. The degree of stenosis in the distal ICA is associated with wall thickening and its longitudinal extent in the upstream segments. CLINICAL RELEVANCE STATEMENT: Diffuse wall thickening is a common secondary change in atherosclerotic steno-occlusive disease in the intracranial carotid. This phenomenon constitutes a confounding factor in the distinction between atherosclerosis and inflammatory vasculopathies, and could be reversed after alleviated atherosclerotic stenosis. KEY POINTS: • Diffuse wall thickening of the petrous internal carotid artery is commonly detected in patients with atherosclerotic steno-occlusive disease in the distal internal carotid artery. • The phenomenon of diffuse wall thickening could be reversed after stenosis alleviation. • Carotid artery atherosclerosis with diffuse wall thickening should warrant a differential diagnosis from other steno-occlusive diseases, including moyamoya diseases and Takayasu aortitis.

Slower changes in vegetation phenology than precipitation seasonality in the dry tropics.

The dry tropics occupy ~40% of the tropical land surface and play a dominant role in the trend and interannual variability of the global carbon cycle. Previous studies have reported considerable changes in the dry tropical precipitation seasonality due to climate change, however, the accompanied changes in the length of the vegetation growing season (LGS)-the key period of carbon sequestration-have not been examined. Here, we used long-term satellite observations along with in-situ flux measurements to investigate phenological changes in the dry tropics over the past 40 years. We found that only ~18% of the dry tropics show a significant (p ≤ .1) increasing trend in LGS, while ~13% show a significant decreasing trend. The direction of the LGS change depended not only on the direction of precipitation seasonality change but also on the vegetation water use strategy (i.e. isohydricity) as an adaptation to the long-term average precipitation seasonality (i.e. whether the most of LGS is in the wet season or dry season). Meanwhile, we found that the rate of LGS change was on average ~23% slower than that of precipitation seasonality, caused by a buffering effect from soil moisture. This study uncovers potential mechanisms driving phenological changes in the dry tropics, offering guidance for regional vegetation and carbon cycle studies.

Development of fluorescent GO-AgNPs-Eu3+ nanoparticles based paper visual sensor for foodborne spores detection.

Foodborne spores are ubiquitous with extremely strong resistance, and pose a serious threat to food safety and human health. Therefore, rapid, sensitive, and selective detection of spores are crucial. In this study, a fluorescent probe was developed based on lanthanide ion (Eu3+)-labeled nano-silver-modified graphene oxide (GO-AgNPs-Eu3+) for the detection of 2,6-dipicolinic acid (DPA), a biomarker unique to spores, to allow quantitative spores detection. The GO-AgNPs-Eu3+ nano-fluorescent probe was loaded onto a polyvinylidene fluoride microfiltration membrane, and a smartphone-assisted portable GO-AgNPs-Eu3+ nanoparticles-based paper visual sensor was designed for rapid on-site quantitative and real-time online detection of spores. The results indicated that the developed probe achieved equilibrium binding with DPA within 5 min, and enhanced fluorescence emission through antenna effect. The fluorescence detection presented a good linear relationship in the DPA concentration range of 0-45 µM, with a DPA detection limit of 4.62 nM and spore detection limit of 104 cfu/mL. The developed sensor showed a change in fluorescence from blue to red with increasing DPA concentration, and this color change was quantitatively detected through smartphone RGB variations, with a detection limit of 13.1 µM for DPA and 6.3 cfu/mL for Bacillus subtilis spores. Subsequently, the sensitivity and selectivity of the developed sensor were verified using actual milk and water samples spiked with B. subtilis spores. The results of this study provided objective technological support for rapid detection of spores, which is important for reducing the occurrence of foodborne diseases and improving food safety.

Encapsulation and assessment of therapeutic cargo in engineered exosomes: a systematic review.

Exosomes are nanoscale extracellular vesicles secreted by cells and enclosed by a lipid bilayer membrane containing various biologically active cargoes such as proteins, lipids, and nucleic acids. Engineered exosomes generated through genetic modification of parent cells show promise as drug delivery vehicles, and they have been demonstrated to have great therapeutic potential for treating cancer, cardiovascular, neurological, and immune diseases, but systematic knowledge is lacking regarding optimization of drug loading and assessment of delivery efficacy. This review summarizes current approaches for engineering exosomes and evaluating their drug delivery effects, and current techniques for assessing exosome drug loading and release kinetics, cell targeting, biodistribution, pharmacokinetics, and therapeutic outcomes are critically examined. Additionally, this review synthesizes the latest applications of exosome engineering and drug delivery in clinical translation. The knowledge compiled in this review provides a framework for the rational design and rigorous assessment of exosomes as therapeutics. Continued advancement of robust characterization methods and reporting standards will accelerate the development of exosome engineering technologies and pave the way for clinical studies.

Revealing the conformational dynamics of UDP-GlcNAc recognition by O-GlcNAc transferase via Markov state model.

The O-linked N-acetylglucosamine (O-GlcNAc) glycosylation is a critical post-translational modification and closely linked to various physiological and pathological conditions. The O-GlcNAc transferase (OGT) functions as the only glycosyltransferase of O-GlcNAc glycosylation by transferring GlcNAc from UDP-GlcNAc to serine or threonine residues on protein substrates. The interaction mode of UDP-GlcNAc against OGT has been preliminarily revealed by the crystal structures, yet an atomic-level comprehension for the conformational dynamics of the recognition process remains elusive. Here, we construct the Markov state model based on extensive all-atom molecular dynamics (MD) simulations with an aggregated simulation time of ∼9 µs, and reveal that the UDP-GlcNAc recognition process by OGT encompasses four key metastable states, occurring within an estimated timescale of ∼10 µs. During UDP-GlcNAc recognition process, we find the pyrophosphate moiety (P2O52-) initially anchors to the active pocket via salt bridge and hydrogen bonds, facilitating subsequent binding of the uridine and GlcNAc moieties. Furthermore, the functional roles of K842 involved in the salt bridge with P2O52- were evaluated through extra mutant MD simulations. Overall, our study provides valuable insights into the UDP-GlcNAc recognition mechanism by OGT, which could further aid in mechanistic studies of O-GlcNAc glycosylation and drug development targeting on OGT.

Characterization of lamb shashliks with different roasting methods by intelligent sensory technologies and GC-MS to simulate human muti-sensation: Based on multimodal deep learning.

To simulate the functions of olfaction, gustation, vision, and oral touch, intelligent sensory technologies have been developed. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) with electronic noses (E-noses), electronic tongues (E-tongues), computer vision (CVs), and texture analyzers (TAs) was applied for sensory characterization of lamb shashliks (LSs) with various roasting methods. A total of 56 VOCs in lamb shashliks with five roasting methods were identified by HS-SPME/GC-MS, and 21 VOCs were identified as key compounds based on OAV (>1). Cross-channel sensory Transformer (CCST) was also proposed and used to predict 19 sensory attributes and their lamb shashlik scores with different roasting methods. The model achieved satisfactory results in the prediction set (R2 = 0.964). This study shows that a multimodal deep learning model can be used to simulate assessor, and it is feasible to guide and correct sensory evaluation.

Engineered Exosome for Drug Delivery: Recent Development and Clinical Applications.

Exosomes are nano-sized membrane vesicles that transfer bioactive molecules between cells and modulate various biological processes under physiological and pathological conditions. By applying bioengineering technologies, exosomes can be modified to express specific markers or carry therapeutic cargo and emerge as novel platforms for the treatment of cancer, neurological, cardiovascular, immune, and infectious diseases. However, there are many challenges and uncertainties in the clinical translation of exosomes. This review aims to provide an overview of the recent advances and challenges in the translation of engineered exosomes, with a special focus on the methods and strategies for loading drugs into exosomes, the pros and cons of different loading methods, and the optimization of exosome production based on the drugs to be encapsulated. Moreover, we also summarize the current clinical applications and prospects of engineered exosomes, as well as the potential risks and limitations that need to be addressed in exosome engineering, including the standardization of exosome preparation and engineering protocols, the quality and quantity of exosomes, the control of drug release, and the immunogenicity and cytotoxicity of exosomes. Overall, engineered exosomes represent an exciting frontier in nanomedicine, but they still face challenges in large-scale production, the maintenance of storage stability, and clinical translation. With continuous advances in this field, exosome-based drug formulation could offer great promise for the targeted treatment of human diseases.

Construction of Graphene@Ag-MLF composite structure SERS platform and its differentiating performance for different foodborne bacterial spores.

A new surface-enhanced Raman spectroscopy (SERS) biosensor of Graphene@Ag-MLF composite structure has been fabricated by loading AgNPs on graphene films. The response of the biosensor is  based on plasmonic sensing. The results showed that the enhancement factor of three different spores reached 107 based on the Graphene@Ag-MLF substrate. In addition, the SERS performance was stable, with good reproducibility (RSD<3%). Multivariate statistical analysis and chemometrics were used to distinguish different spores. The accumulated variance contribution rate was up to 96.35% for the top three PCs, while HCA results revealed that the spectra were differentiated completely. Based on optimal principal components, chemometrics of KNN and LS-SVM were applied to construct a model for rapid qualitative identification of different spores, of which the prediction set and training set of LS-SVM achieved 100%. Finally, based on the Graphene@Ag-MLF substrate, the LOD of three different spores was lower than 102 CFU/mL. Hence, this novel Graphene@Ag-MLF SERS substrate sensor was rapid, sensitive, and stable in detecting spores, providing strong technical support for the application of SERS technology in food safety.

Solar driven CO2 hydrogenation to HCOOH on (TiO2)n (n = 1-6) atomic clusters.

Artificial photosynthesis is a crucial reaction that addresses energy and environmental challenges by converting CO2 into fuels and value-added chemicals. However, efficient catalytic activity using earth-abundant materials can be challenging due to intrinsic limitations. Herein, we explore neutral (TiO2)n (n = 1-6) atomic clusters for CO2 hydrogenation via comprehensive ab initio calculations combined with time-dependent functional theory. Our results show that these (TiO2)n clusters exhibit outstanding thermodynamic stabilities and decent surficial activities for CO2 activation and H2 dissociation, both of which possess kinetic barriers down to 0-0.74 eV. We establish a relationship between the binding strength of *CO2 species and electron characterization for these (TiO2)n clusters. These clusters, which have a wide energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccpied molecular orbital (LUMO) that allows them to harvest the solar light in the ultraviolet regime, enabling efficient catalysis for driving the catalysis of CO2 conversion. They provide exclusive reaction channels and high selectivity for yielding HCOOH products via the carboxyl mechanism, involving the kinetic barrier of the limiting step of 0.74-1.25 eV. We also investigated the substrate effect on supported (TiO2)n clusters, with non-metallic substrates featuring inert surfaces serving as suitable options for anchoring (TiO2)n clusters while preserving their intrinsic activity and selectivity. These computational results have significant implications not only for meeting energy demands but also for mitigating carbon emissions by utilizing CO2 as an alternative feedstock rather than considering it solely as a greenhouse gas.

Metabolomics and transcriptomics analyses provide new insights into the nutritional quality during the endosperm development of different ploidy rice.

Autotetraploid rice is developed from diploid rice by doubling the chromosomes, leading to higher nutritional quality. Nevertheless, there is little information about the abundances of different metabolites and their changes during endosperm development in autotetraploid rice. In this research, two different kinds of rice, autotetraploid rice (AJNT-4x) and diploid rice (AJNT-2x), were subjected to experiments at various time points during endosperm development. A total of 422 differential metabolites, were identified by applying a widely used metabolomics technique based on LC-MS/MS. KEGG classification and enrichment analysis showed the differences in metabolites were primarily related to biosynthesis of secondary metabolites, microbial metabolism in diverse environments, biosynthesis of cofactors, and so on. Twenty common differential metabolites were found at three developmental stages of 10, 15 and 20 DAFs, which were considered the key metabolites. To identify the regulatory genes of metabolites, the experimental material was subjected to transcriptome sequencing. The DEGs were mainly enriched in starch and sucrose metabolism at 10 DAF, and in ribosome and biosynthesis of amino acids at 15 DAF, and in biosynthesis of secondary metabolites at 20 DAF. The numbers of enriched pathways and the DEGs gradually increased with endosperm development of rice. The related metabolic pathways of rice nutritional quality are cysteine and methionine metabolism, tryptophan metabolism, lysine biosynthesis and histidine metabolism, and so on. The expression level of the genes regulating lysine content was higher in AJNT-4x than in AJNT-2x. By applying CRISPR/Cas9 gene-editing technology, we identified two novel genes, OsLC4 and OsLC3, negatively regulated lysine content. These findings offer novel insight into dynamic metabolites and genes expression variations during endosperm development of different ploidy rice, which will aid in the creation of rice varieties with better grain nutritional quality.

Mechanistic insights into severe pulmonary inflammation caused by silica stimulation: The role of macrophage pyroptosis.

Respirable silica dust is a common hazard faced by occupational workers and prolonged exposure to this dust can lead to pulmonary inflammation, fibrosis and, in severe cases, silicosis. However, the underlying mechanism by which silica exposure causes these physical disorders is not yet understood. In this study, we aimed to shed light on this mechanism by establishing in vitro and in vivo silica exposure models from the perspective of macrophages. Our results showed that compared to the control group, silica exposure resulted in an upregulation of the pulmonary expression of P2X7 and Pannexin-1, but this effect was suppressed by treatment with MCC950, a specific inhibitor of NLRP3. Our in vitro studies showed that silica exposure induced mitochondrial depolarization in macrophages, which led to a reduction of intracellular ATP and an influx of Ca2+. Furthermore, we found that creating an extracellular high potassium environment by adding KCl to the macrophage medium inhibited the expression of pyroptotic biomarkers and pro-inflammatory cytokines such as NLRP3 and IL-1ß. Treatment with BBG, a P2X7 antagonist, also effectively inhibited the expression of P2X7, NLRP3, and IL-1ß. On the other hand, treatment with FCF, a Pannexin-1 inhibitor, suppressed the expression of Pannexin-1 but had no effect on the expression of pyroptotic biomarkers such as P2X7, NLRP3, and IL-1ß. In conclusion, our findings suggest that silica exposure triggers the opening of P2X7 ion channels, resulting in intracellular K+ efflux, extracellular Ca2+ influx, and the assembly of the NLRP3 inflammasome, ultimately leading to macrophage pyroptosis and pulmonary inflammation.