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Increasing density is an effective way to enhance wheat (Triticum aestivum L.) yield under limited cultivated areas. However, the physiological mechanisms underlying the reduction in grain weight when density increased are still unclear. Three field experiments were conducted during the 2014–2019 growing seasons to explore the physiological mechanisms by which polyamines affect grain weight formation. The results showed that when wheat planting density exceeded 450 × 104 seedlings ha−1 and 525 × 104 seedlings ha−1, wheat yield tended to decrease. Compared to moderate density (DM, 450 × 104 seedlings ha−1), the filling rate of inferior grains was reduced before 25 days after anthesis (DAA) and the active filling period was shortened by 6.4%–7.4% under high density (DH, 600 × 104 seedlings ha−1), resulting in a loss of 1000‐grain weight by 5.4%–8.1%. DH significantly reduced sucrose and starch content in inferior grains at the filling stage. Meanwhile, DH inhibited the activity of key enzymes involved in polyamine synthesis [SAMDC (EC 4.1.1.50) and SpdSy (EC 2.5.1.16)] and induced the activity of ethylene (ETH) precursor synthase, resulting in a significant decrease in endogenous spermidine (Spd) content in inferior grains, but a significant increase in ETH release rate. Post‐flowering application of exogenous Spd increased the accumulation of sucrose and starch in the inferior grains and positively regulated the filling and grain weight of the inferior grains, whereas exogenous ETH had a negative effect. Overall, Spd may affect wheat grain weight at high planting density by promoting the synthesis of sucrose and starch in inferior grains. [ABSTRACT FROM AUTHOR]

The purpose of this study was to study and analyze the composition and content of routine nutrients, amino acids, fatty acids, and mineral elements in muscle of three cultured populations of Cipangopaludina cathayensis, so as to provide a reference for the development and utilization of Cipangopaludina cathayensis germplasm resources. A total of 180 Cipangopaludina cathayensis with an average weight of (32.12±0.17) g were randomly divided into three groups with 60 Cipangopaludina cathayensis in each group. After shelling, the muscles were taken to test their nutritional components. The results showed that the crude protein, total amino acids, essential amino acids, and delicious amino acids in muscle of Luchuan County population were significantly higher than those of other populations (P<0.05). The amino acid score, chemical score, and essential amino acid index of Liujiang population were the highest. The contentrations of unsaturated fatty acids and polyunsaturated fatty acids in muscle of Luchuan County population were significantly higher than those of other populations, and the atherosclerosis index (IA) and thrombosis index (IT) were lower than those of other populations (P<0.05). The ratio of sigma-n-3/sigma-n-6PUFA of the three populations was in line with the recommended value of FAO/WHO for human diet (0.1~0.2). The contentrations of P and Ca in muscle of Rongshui County population were significantly higher than those of other populations (P<0.05). The study indicates that the muscle protein content of the three cultured populations is higher, the fat content is lower, and the delicious amino acids and unsaturated fatty acids are higher. The nutritional value of the muscle of Luchuan County population are better than those of other populations. [ABSTRACT FROM AUTHOR]

Lung cancer is the leading global cause of cancer‐related death, however, resistance to chemotherapy drugs remains a huge barrier to effective treatment. The elevated recruitment of myeloid derived suppressor cells (MDSCs) to tumour after chemotherapy has been linked to resistance of chemotherapy drugs. Nevertheless, the specific mechanism remains unclear. oxPAPC is a bioactive principal component of minimally modified low‐density lipoproteins and regulates inflammatory response. In this work, we found that cisplatin, oxaliplatin and ADM all increased oxPAPC release in tumour. Treating macrophages with oxPAPC in vitro stimulated the secretion of MCP‐1 and LTB4, which strongly induced monocytes and neutrophils chemotaxis, respectively. Injection of oxPAPC in vivo significantly upregulated the percentage of MDSCs in tumour microenvironment (TME) of wild‐type LL2 tumour‐bearing mice, but not CCL2−/− mice and LTB4R−/− mice. Critically, oxPAPC acted as a pro‐tumor factor in LL2 tumour model. Indeed, cisplatin increased oxPAPC level in tumour tissues of WT mice, CCL2−/− and LTB4R−/− mice, but caused increased infiltration of Ly6Chigh monocytes and neutrophils only in WT LL2‐bearing mice. Collectively, our work demonstrates cisplatin treatment induces an overproduction of oxPAPC and thus recruits MDSCs infiltration to promote the tumour growth through the MCP‐1/CCL2 and LTB4/LTB4R pathways, which may restrict the effect of multiple chemotherapy. This provides evidence for a potential strategy to enhance the efficacy of multiple chemotherapeutic drugs in the treatment of lung cancer by targeting oxPAPC. [ABSTRACT FROM AUTHOR]

Drought stress poses a serious threat to grain formation in wheat. Nitrogen (N) plays crucial roles in plant organ development; however, the physiological mechanisms by which drought stress affects plant N availability and mediates the formation of grains in spikes of winter wheat are still unclear. In this study, we determined that pre-reproductive drought stress significantly reduced the number of fertile florets and the number of grains formed. Transcriptome analysis demonstrated that this was related to N metabolism, and in particular, the metabolism pathways of arginine (the main precursor for synthesis of polyamine) and proline. Continuous drought stress restricted plant N accumulation and reallocation rates, and plants preferentially allocated more N to spike development. As the activities of amino acid biosynthesis enzymes and catabolic enzymes were inhibited, more free amino acids accumulated in young spikes. The expression of polyamine synthase genes was down-regulated under drought stress, whilst expression of genes encoding catabolic enzymes was enhanced, resulting in reductions in endogenous spermidine and putrescine. Treatment with exogenous spermidine optimized N allocation in young spikes and leaves, which greatly alleviated the drought-induced reduction in the number of grains per spike. Overall, our results show that pre-reproductive drought stress affects wheat grain numbers by regulating N redistribution and polyamine metabolism. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Ammonia promotes the proliferation of bone marrow-derived mesenchymal stem cells by regulating the Akt/mTOR/S6k pathway" published in Bone Research. The authors identified mistakes in Figures 1c and 5d after the article was published online. The revisions made to these figures do not affect the conclusions of the study. The corrected figures and their accompanying legends are provided in the document. The original article has been updated. [Extracted from the article]

The preferable antigen delivery profile accompanied by sufficient adjuvants favors vaccine efficiency. Mitochondria, which feature prokaryotic characteristics and contain various damage-associated molecular patterns (DAMPs), are easily taken up by phagocytes and simultaneously activate innate immunity. In the current study, we established a mitochondria engineering platform for generating antigen-enriched mitochondria as cancer vaccine. Ovalbumin (OVA) and tyrosinase-related protein 2 (TRP2) were used as model antigens to synthesize fusion proteins with mitochondria-localized signal peptides. The lentiviral infection system was then employed to produce mitochondrial vaccines containing either OVA or TRP2. Engineered OVA- and TRP2-containing mitochondria (OVA-MITO and TRP2-MITO) were extracted and evaluated as potential cancer vaccines. Impressively, the engineered mitochondria vaccine demonstrated efficient antitumor effects when used as both prophylactic and therapeutic vaccines in murine tumor models. Mechanistically, OVA-MITO and TRP2-MITO potently recruited and activated dendritic cells (DCs) and induced a tumor-specific cell-mediated immunity. Moreover, DC activation by mitochondria vaccine critically involves TLR2 pathway and its lipid agonist, namely, cardiolipin derived from the mitochondrial membrane. The results demonstrated that engineered mitochondria are natively well-orchestrated carriers full of immune stimulants for antigen delivery, which could preferably target local dendritic cells and exert strong adaptive cellular immunity. This proof-of-concept study established a universal platform for vaccine construction with engineered mitochondria bearing alterable antigens for cancers as well as other diseases., (© 2024. The Author(s).)

Microbial necromass carbon (MNC) contributes significantly to the formation of soil organic carbon (SOC). However, the microbial carbon sequestration effect of biochar is often underestimated and influenced by nutrient availability. The mechanisms associated with the formation and stabilization of MNC remain unclear, especially under the combined application of biochar and nitrogen (N) fertilizer. Thus, in a long-term field experiment (11 years) based on biochar application, we utilized bacterial 16S rRNA gene sequencing, fungal ITS amplicon sequencing, metagenomics, and microbial biomarkers to examine the interactions between MNC accumulation and microbial metabolic strategies under combined treatment with biochar and N fertilizer. We aimed to identify the critical microbial modules and species involved, and to analyze the sites where MNC was immobilized from various components. Biochar application increased the MNC content by 13.9 %. Among the MNC components, fungal necromass contributed more to MNC, but bacteria were more readily enriched after biochar application. The microbial life-history strategies that affected MNC formation under the application of various amounts biochar were linked to the N application level. Under N added at 226.5 kg ha -1 , communities such as Actinobacteria and Bacteroidetes with high-growth yield strategies were prevalent and contributed to MNC production. By contrast, under N added at 113.25 kg ha -1 with high biochar application, Proteobacteria with strong resource acquisition strategies were dominant and MNC accumulation was lower. The mineral-associated organic carbon pool was rapidly saturated with the addition of biochar, so the contribution of fungal necromass carbon may have been reduced by reutilization, thereby resulting in the more rapid preservation of bacterial necromass carbon in the particulate organic carbon pool. Overall, our findings indicate that microbial life history traits are crucial for linking microbial metabolic processes to the accumulation and stabilization of MNC, thereby highlighting the their importance for SOC accumulation in farmland soils, and the need to tailor appropriate biochar and N fertilizer application strategies for agricultural soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Acinetobacter baumannii ( A. baumannii ) is an important opportunistic pathogen causing nosocomial infection in the clinic. The occurrence rate of antibiotic resistance is increasing year by year, resulting in a highly serious situation of bacterial resistance., Methods: To better understand the local epidemiology of multidrug-resistant A. baumannii , an investigation was conducted on the antibiotic resistance of different types of A. baumannii and its relationship with the genes of A. baumannii . Furthermore, the molecular mechanism underlying antibiotic resistance in A. baumannii was investigated through transcriptome analysis., Results: These results showed that a total of 9 STs were detected. It was found that 99% of the strains isolated in the hospital belonged to the same STs, and the clone complex CC208 was widely distributed in various departments and all kinds of samples. Furthermore, these A. baumannii strains showed high resistance to ertapenem, biapenem, meropenem, and imipenem, among which the resistance to ertapenem was the strongest. The detection rate of bla OXA -51 gene in these carbapenem resistance A. baumannii (CRAB) reached 100%; Additionally, the transcriptome results showed that the resistance genes were up-regulated in resistance strains, and these genes involved in biofilm formation, efflux pumps, peptidoglycan biosynthesis, and chaperonin synthesis., Discussion: These results suggest that the CC208 STs were the main clonal complex, and showed high carbapenem antibiotic resistance. All these resistant strains were distributed in various departments, but most of them were distributed in intensive care units (ICU). The bla OXA -23 was the main antibiotic resistance genotype; In summary, the epidemic trend of clinical A. baumannii in Guiyang, China was analyzed from the molecular level, and the resistance mechanism of A. baumannii to carbapenem antibiotics was analyzed with transcriptome, which provided a theoretical basis for better control of A. baumannii ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Qiu, Yuan, Cao, Chen, Chen, Mo, Guo and Peng.)