Protein crotonylation promotes osteogenic differentiation of periodontal ligament stem cells via the PI3K-AKT pathway.

Posttranslational modifications are crucial regulatory mechanisms for cellular differentiation and organismal development. Acylation modification is one of the main posttranslational modifications that play a pivotal role in regulating the osteogenic differentiation of mesenchymal stem cells and is a focal point of research in bone tissue regeneration. However, its mechanism remains incompletely understood. This article aims to investigate the impact of protein crotonylation on osteogenic differentiation in periodontal ligament stem cells (PDLSCs) and elucidate its underlying mechanisms. Western blot analysis identified that the modification level of acetylation, crotonylation and succinylation were significantly upregulated after osteogenic induction of PDLSCs. Subsequently, sodium crotonate (NaCr) was added to the medium and acyl-CoA synthetase short-chain family member 2 (ACSS2) was knocked down by short hairpin RNA plasmids to regulate the total level of protein crotonylation. The results indicated that treatment with NaCr promoted the expression of osteogenic differentiation-related factors in PDLSCs, whereas silencing ACSS2 had the opposite effect. In addition, mass spectrometry analysis was used to investigate the comprehensive analysis of proteome-wide crotonylation in PDLSCs under osteogenic differentiation. The analysis revealed that the level of protein crotonylation related to the PI3K-AKT signaling pathway was significantly upregulated in PDLSCs after osteogenic induction. Treatment with NaCr and silencing ACSS2 affected the activation of the PI3K-AKT signaling pathway. Collectively, our study demonstrates that protein crotonylation promotes osteogenic differentiation of PDLSCs via the PI3K-AKT pathway, providing a novel targeting therapeutic approach for bone tissue regeneration.

Venture capital, innovation channels, and regional resource dependence: Evidence from China.

Although the literature predominantly emphasises the crucial role of technological innovation in alleviating resource dependence, limited attention has been given to the pivotal role of capital in driving such innovation. As a critical factor in technological advancements and productivity enhancement, venture capital has a substantial function in the utilisation of resources and the development of sustainable energy sources. Drawing upon panel data from 30 provinces in China, this study explores how venture capital and resource dependence are interrelated. Our research reveals that venture capital effectively mitigates regional resource dependence by facilitating increased investment in innovation channels. However, the weakening of regional human resources mitigates venture capital's diminishing impacts on resource dependence. These findings provide valuable insights for countries seeking to reduce their dependence on natural resources and achieve long-term economic sustainability.

Navigating the nexus: Geopolitical risk, fossil energy prices, and European utility stock returns - Implications for environmental management and energy security in a conflict-ridden global landscape.

This study employs a TPV-VAR analysis method to explore the linkage between GPR, fossil energy prices, and utility stock returns across 16 European countries from August 2009 to April 2023. Our findings reveal variations over time in how GPR influences the prices of fossil energy and utility stock returns. GPR significantly influences stock returns in the short term (1 month), with prolonged effects observed during major geopolitical incidents, while showing no significance in the medium (6 months) and long term (12 months). Further, the Russia-Ukraine War had a more pronounced impact on fossil energy prices and utility stock returns compared with the Arab Spring and Brexit. Finally, GPR shocks exhibit heterogeneous effects on different fossil energy types, with oil prices being more affected than coal and gas prices. Energy prices act as a channel through which GPR influences utility stock returns. This study elucidates the linkage between GPR, prices of fossil energy, and stock returns, offering valuable perspectives for governments and investment decision-makers into risk management.

A facile strategy to prepare FeNx decorated PtFe intermetallic with excellent acidic oxygen reduction reaction activity and stability.

The construction of low-Pt-content intermetallic on carbon supports has been verified as a promising method to promote the activity of the oxygen reduction reaction (ORR). In this study, we have developed a simple and effective strategy to obtain a well-designed CNT-PtFe-PPy precursor. This precursor contains modulated Pt- and Fe-based content dispersed in polypyrrole (PPy) chain segments, which are in-situ generated on the templates of carbon nanotubes (CNTs). Subsequent pyrolysis of the CNT-PtFe-PPy precursor produces a CNT-PtFe@FeNC catalyst, which contains both Fe-Nx and PtFe intermetallic active sites. Due to the highly efficient dispersion of active species, the CNT-PtFe@FeNC electrocatalyst displays a 9.5 times higher specific activity (SA) and 8.5 times higher mass activity (MA) than those of a commercial Pt/C catalyst in a 0.1 M HClO4 solution. Additionally, these results, combined with excellent durability (the SA and MA maintained 94 % and 91 % of initial activity after a 10-k cycle accelerated durability test), represent among the best performance achieved so far for Pt-based ORR electrocatalysts. Furthermore, density functional theory (DFT) calculations revealed that the presence of Fe-N4 species reduces the adsorption energy between the PtFe intermetallic compound and OH*, accelerating the ORR process.

Transcriptomics and Phenotypic Analysis of gpr56 Knockout in Zebrafish.

The adhesion G-protein-coupled receptor is a seven-transmembrane receptor protein with a complex structure. Impaired GPR56 has been found to cause developmental damage to the human brain, resulting in intellectual disability and motor dysfunction. To date, studies on gpr56 deficiency in zebrafish have been limited to the nervous system, and there have been no reports of its systemic effects on juvenile fish at developmental stages. In order to explore the function of gpr56 in zebrafish, the CRISPR/Cas9 gene-editing system was used to construct a gpr56-knockout zebrafish. Subsequently, the differentially expressed genes (DEGs) at the transcriptional level between the 3 days post fertilization (dpf) homozygotes of the gpr56 mutation and the wildtype zebrafish were analyzed via RNA-seq. The results of the clustering analysis, quantitative PCR (qPCR), and in situ hybridization demonstrated that the expression of innate immunity-related genes in the mutant was disordered, and multiple genes encoding digestive enzymes of the pancreatic exocrine glands were significantly downregulated in the mutant. Motor ability tests demonstrated that the gpr56-/- zebrafish were more active, and this change was more pronounced in the presence of cold and additional stimuli. In conclusion, our results revealed the effect of gpr56 deletion on the gene expression of juvenile zebrafish and found that the gpr56 mutant was extremely active, providing an important clue for studying the mechanism of gpr56 in the development of juvenile zebrafish.

Type-2 epithelial-mesenchymal transition in oral mucosal nonneoplastic diseases.

The oral mucosa is a membranous structure comprising epithelial and connective tissue that covers the oral cavity. The oral mucosa is the first immune barrier to protect the body against pathogens for systemic protection. It is frequently exposed to mechanical abrasion, chemical erosion, and pathogenic invasion, resulting in oral mucosal lesions, particularly inflammatory diseases. Epithelial-mesenchymal transition (EMT) is a crucial biological process in the pathogenesis of oral mucosal disorders, which are classified into three types (types 1, 2, and 3) based on their physiological consequences. Among these, type-2 EMT is crucial in wound repair, organ fibrosis, and tissue regeneration. It causes infectious and dis-infectious immunological diseases, such as oral lichen planus (OLP), oral leukoplakia, oral submucosal fibrosis, and other precancerous lesions. However, the mechanism and cognition between type-2 EMT and oral mucosal inflammatory disorders remain unknown. This review first provides a comprehensive evaluation of type-2 EMT in chronically inflammatory oral mucosal disorders. The aim is to lay a foundation for future research and suggest potential treatments.

Plant phenomics & precision agriculture simulation of winter wheat growth by the assimilation of unmanned aerial vehicle imagery into the WOFOST model.

The aim of this study is to optimize the simulation result of the WOFOST model and explore the possibility of assimilating unmanned aerial vehicle (UAV) imagery into this model. Field images of wheat during its key growth stages are acquired with a UAV, and the corresponding leaf area index (LAI), biomass, and final yield are experimentally measured. LAI data is retrieved from the UAV imagery and assimilated into a localized WOFOST model using least squares optimization. Sensitive parameters, i.e., specific leaf area (SLATB0, SLATB0.5, SLATB2) and maximum CO2 assimilation rate (AMAXTB1, AMAXTB1.3) are adjusted to minimize the discrepancy between the LAI obtained from the model simulation and inversion of the UAV data. The results show that the assimilated model provides a better estimation of the growth and development of winter wheat in the study area. The R2, RMSE, and NRMSE of winter wheat LAI simulated with the assimilated WOFOST model are 0.8812, 0.49, and 23.5% respectively. The R2, RMSE, and NRMSE of the simulated yield are 0.9489, 327.06 kg·hm-2, and 6.5%. The accuracy in model simulation of winter wheat growth is improved, which demonstrates the feasibility of integrating UAV data into crop models.

Measuring pollutant emissions of cattle breeding and its spatial-temporal variation in China.

The rapid development of animal husbandry has resulted in serious pollution issues in the livestock and poultry breeding industry, increasing the cost of environmental management. This issue is particularly prominent in China due to its rapid economic development, significant domestic consumption, and aggressive carbon neutrality targets. This study analyses pollution emissions and spatial-temporal variation in China's cattle breeding industry. Using an emission coefficient method and panel data of 31 Chinese provinces/municipalities between 2002 and 2017, we measure the total volume of pollutant emissions from China's cattle breeding industry and five major pollutants: chemical oxygen demand, total nitrogen, total phosphorus, copper, and zinc. We also analyse the dynamic variation of the spatial distribution. The results show that both the total emissions volume and emissions of the five major pollutants have decreased to different extents, among which chemical oxygen demand has decreased the fastest. Spatial divergence is strengthened as the heavy pollution areas have moved from the southeast to the northwest of the country. This study contributes to current research by its focus on the cattle breading industry and by our improvements to the pollutant emission measurement method.

Carbon dioxide emissions and Chinese OFDI: From the perspective of carbon neutrality targets and environmental management of home country.

Studies investigating the relationship between foreign direct investment (FDI) and the environment have focused predominantly on the effects of FDI on host country environments with less attention paid to the impact on home countries. This study turns its attention to the effects of outward foreign direct investment (OFDI) on a home country's carbon dioxide emissions. We use three paths through which OFDI can affect the carbon dioxide emissions of a home country, including economic scale, technology level, and industry composition effects. Using a simultaneous equation model and panel data of 30 provinces of China for the period of 2003-2017, this study finds that OFDI is positively related to the carbon dioxide emissions of the home country, though the effects of emissions have weakened dynamically due the technology developments brought about by OFDI. More specifically, we find that both 'pollution haven' and 'pollution halo' effects existing in three different paths. The paths of industry composition and technology level show negative effects on carbon dioxide emissions, whilst the path of economic scale is positive. OFDI is also found to be negatively related to the carbon intensity of the home country.

Image analysis-based recognition and quantification of grain number per panicle in rice.

BACKGROUND: The number grain per panicle of rice is an important phenotypic trait and a significant index for variety screening and cultivation management. The methods that are currently used to count the number of grains per panicle are manually conducted, making them labor intensive and time consuming. Existing image-based grain counting methods had difficulty in separating overlapped grains. RESULTS: In this study, we aimed to develop an image analysis-based method to quickly quantify the number of rice grains per panicle. We compared the counting accuracy of several methods among different image acquisition devices and multiple panicle shapes on both Indica and Japonica subspecies of rice. The linear regression model developed in this study had a grain counting accuracy greater than 96% and 97% for Japonica and Indica rice, respectively. Moreover, while the deep learning model that we used was more time consuming than the linear regression model, the average counting accuracy was greater than 99%. CONCLUSIONS: We developed a rice grain counting method that accurately counts the number of grains on a detached panicle, and believe this method can be a huge asset for guiding the development of high throughput methods for counting the grain number per panicle in other crops.

Isolation, structure and activity of a novel water-soluble polysaccharide from Dioscorea opposita Thunb.

A previously unknown, water-soluble polysaccharide, named DOTP-B, was isolated from the roots of the plant Dioscorea opposita Thunb, a well-known edible and medicinal plant in China. DOTP-B was found to be neutral in charge, with an average molecular weight of 5623 Da. Monosaccharide composition analysis by GC-MS revealed that DOTP-B was a hetero-polysaccharide consisting of glucose and galactose at a molar ratio of 14.6:1.0. Structural features of DOTP-B were investigated with a combination of chemical and instrumental methods, including complete acid hydrolysis, periodate oxidation, methylation, GC-MS, FTIR and several NMR spectra. Highly correlated results demonstrated that the main chain of DOTP-B consisted of →4)-α-d-glc(1 → residues, with about 6% internal →6)-ß-d-gal(1 → residues. The antioxidant activity of DOTP-B was also evaluated as the EC50 values against DPPH and PTIO radicals were 2.1 ±â€¯0.1 mg/mL and 1.6 ±â€¯0.1 mg/mL, respectively. Therefore, the polysaccharide DOTP-B could be possibly developed as a promising natural antioxidant for application in medical and food industries.

A method to calculate the number of wheat seedlings in the 1st to the 3rd leaf growth stages.

BACKGROUND: The number of cultivated wheat seedlings per unit area allows calculation of plant density. Wheat seedling density provides emergence data and this is useful for improving crop management. The number of wheat seedlings is typically determined by visual counts but this is time-consuming and laborious. RESULTS: We obtained field digital images of 1st to 3rd leaf stage wheat seedlings. The seedlings were extracted using an image analysis technique that calculated the coverage degree of the seedlings and the number of angular points of overlapping leaves. The wheat seedling quantity estimation model was constructed using multivariate regression analysis. The model parameters included coverage degree, number of angular points, variety coefficient, and leaf age. Introduction of the number of angular points increased the accuracy of the single coverage degree model. The R2 value was consistently > 0.95 when the model was applied to different varieties, indicating that the model was adaptable for different varieties. As the leaf stage or density increased, the accuracy of the model declined, but the minimum R2 remained > 0.87, indicating good adaptability of the model to seedlings with different leaf ages and densities. CONCLUSIONS: This method is an effective means for counting wheat seedlings in the 1st to the 3rd leaf stages.

Head rice rate measurement based on concave point matching.

Head rice rate is an important factor affecting rice quality. In this study, an inflection point detection-based technology was applied to measure the head rice rate by combining a vibrator and a conveyor belt for bulk grain image acquisition. The edge center mode proportion method (ECMP) was applied for concave points matching in which concave matching and separation was performed with collaborative constraint conditions followed by rice length calculation with a minimum enclosing rectangle (MER) to identify the head rice. Finally, the head rice rate was calculated using the sum area of head rice to the overall coverage of rice. Results showed that bulk grain image acquisition can be realized with test equipment, and the accuracy rate of separation of both indica rice and japonica rice exceeded 95%. An increase in the number of rice did not significantly affect ECMP and MER. High accuracy can be ensured with MER to calculate head rice rate by narrowing down its relative error between real values less than 3%. The test results show that the method is reliable as a reference for head rice rate calculation studies.

Specific Correction of Alternative Survival Motor Neuron 2 Splicing by Small Molecules: Discovery of a Potential Novel Medicine To Treat Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) is the leading genetic cause of infant and toddler mortality, and there is currently no approved therapy available. SMA is caused by mutation or deletion of the survival motor neuron 1 (SMN1) gene. These mutations or deletions result in low levels of functional SMN protein. SMN2, a paralogous gene to SMN1, undergoes alternative splicing and exclusion of exon 7, producing an unstable, truncated SMNΔ7 protein. Herein, we report the identification of a pyridopyrimidinone series of small molecules that modify the alternative splicing of SMN2, increasing the production of full-length SMN2 mRNA. Upon oral administration of our small molecules, the levels of full-length SMN protein were restored in two mouse models of SMA. In-depth lead optimization in the pyridopyrimidinone series culminated in the selection of compound 3 (RG7800), the first small molecule SMN2 splicing modifier to enter human clinical trials.

Discovery and Optimization of Small Molecule Splicing Modifiers of Survival Motor Neuron 2 as a Treatment for Spinal Muscular Atrophy.

The underlying cause of spinal muscular atrophy (SMA) is a deficiency of the survival motor neuron (SMN) protein. Starting from hits identified in a high-throughput screening campaign and through structure-activity relationship investigations, we have developed small molecules that potently shift the alternative splicing of the SMN2 exon 7, resulting in increased production of the full-length SMN mRNA and protein. Three novel chemical series, represented by compounds 9, 14, and 20, have been optimized to increase the level of SMN protein by >50% in SMA patient-derived fibroblasts at concentrations of <160 nM. Daily administration of these compounds to severe SMA Δ7 mice results in an increased production of SMN protein in disease-relevant tissues and a significant increase in median survival time in a dose-dependent manner. Our work supports the development of an orally administered small molecule for the treatment of patients with SMA.

Enzymes in the NAD+ salvage pathway regulate SIRT1 activity at target gene promoters.

In mammals, nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide mononucleotide adenylyltransferase 1 (NMNAT-1) constitute a nuclear NAD(+) salvage pathway which regulates the functions of NAD(+)-dependent enzymes such as the protein deacetylase SIRT1. One of the major functions of SIRT1 is to regulate target gene transcription through modification of chromatin-associated proteins. However, little is known about the molecular mechanisms by which NAD(+) biosynthetic enzymes regulate SIRT1 activity to control gene transcription in the nucleus. In this study we show that stable short hairpin RNA-mediated knockdown of NAMPT or NMNAT-1 in MCF-7 breast cancer cells reduces total cellular NAD(+) levels and alters global patterns of gene expression. Furthermore, we show that SIRT1 plays a key role in mediating the gene regulatory effects of NAMPT and NMNAT-1. Specifically, we found that SIRT1 binds to the promoters of genes commonly regulated by NAMPT, NMNAT-1, and SIRT1 and that SIRT1 histone deacetylase activity is regulated by NAMPT and NMNAT-1 at these promoters. Most significantly, NMNAT-1 interacts with, and is recruited to target gene promoters by SIRT1. Collectively, our results reveal a mechanism for the direct control of SIRT1 deacetylase activity at a set of target gene promoters by NMNAT-1. This mechanism, in collaboration with NAMPT-dependent regulation of nuclear NAD(+) production, establishes an important pathway for transcription regulation by NAD(+).

Syntheses of nicotinamide riboside and derivatives: effective agents for increasing nicotinamide adenine dinucleotide concentrations in mammalian cells.

A new two-step methodology achieves stereoselective synthesis of beta-nicotinamide riboside and a series of related amide, ester, and acid nucleosides. Compounds were prepared through a triacetylated-nicotinate ester nucleoside, via coupling of either ethylnicotinate or phenylnicotinate with 1,2,3,5-tetra-O-acetyl-beta-D-ribofuranose. Nicotinamide riboside, nicotinic acid riboside, O-ethylnicotinate riboside, O-methylnicotinate riboside, and several N-alkyl derivatives increased NAD+ concentrations from 1.2-2.7-fold in several mammalian cell lines. These findings establish bioavailability and potent effects of these nucleosides in stimulating the increase of NAD+ concentrations in mammalian cells.

Nicotinamide riboside kinase structures reveal new pathways to NAD+.

The eukaryotic nicotinamide riboside kinase (Nrk) pathway, which is induced in response to nerve damage and promotes replicative life span in yeast, converts nicotinamide riboside to nicotinamide adenine dinucleotide (NAD+) by phosphorylation and adenylylation. Crystal structures of human Nrk1 bound to nucleoside and nucleotide substrates and products revealed an enzyme structurally similar to Rossmann fold metabolite kinases and allowed the identification of active site residues, which were shown to be essential for human Nrk1 and Nrk2 activity in vivo. Although the structures account for the 500-fold discrimination between nicotinamide riboside and pyrimidine nucleosides, no enzyme feature was identified to recognize the distinctive carboxamide group of nicotinamide riboside. Indeed, nicotinic acid riboside is a specific substrate of human Nrk enzymes and is utilized in yeast in a novel biosynthetic pathway that depends on Nrk and NAD+ synthetase. Additionally, nicotinic acid riboside is utilized in vivo by Urh1, Pnp1, and Preiss-Handler salvage. Thus, crystal structures of Nrk1 led to the identification of new pathways to NAD+.

Nutrient-sensitive mitochondrial NAD+ levels dictate cell survival.

A major cause of cell death caused by genotoxic stress is thought to be due to the depletion of NAD(+) from the nucleus and the cytoplasm. Here we show that NAD(+) levels in mitochondria remain at physiological levels following genotoxic stress and can maintain cell viability even when nuclear and cytoplasmic pools of NAD(+) are depleted. Rodents fasted for 48 hr show increased levels of the NAD(+) biosynthetic enzyme Nampt and a concomitant increase in mitochondrial NAD(+). Increased Nampt provides protection against cell death and requires an intact mitochondrial NAD(+) salvage pathway as well as the mitochondrial NAD(+)-dependent deacetylases SIRT3 and SIRT4. We discuss the relevance of these findings to understanding how nutrition modulates physiology and to the evolution of apoptosis.

Hormonal control of androgen receptor function through SIRT1.

The NAD-dependent histone deacetylase Sir2 plays a key role in connecting cellular metabolism with gene silencing and aging. The androgen receptor (AR) is a ligand-regulated modular nuclear receptor governing prostate cancer cellular proliferation, differentiation, and apoptosis in response to androgens, including dihydrotestosterone (DHT). Here, SIRT1 antagonists induce endogenous AR expression and enhance DHT-mediated AR expression. SIRT1 binds and deacetylates the AR at a conserved lysine motif. Human SIRT1 (hSIRT1) repression of DHT-induced AR signaling requires the NAD-dependent catalytic function of hSIRT1 and the AR lysine residues deacetylated by SIRT1. SIRT1 inhibited coactivator-induced interactions between the AR amino and carboxyl termini. DHT-induced prostate cancer cellular contact-independent growth is also blocked by SIRT1, providing a direct functional link between the AR, which is a critical determinant of progression of human prostate cancer, and the sirtuins.