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The construction level of artificial grassland is an important index of the development degree of grassland animal husbandry. Therefore, improving the productivity level of artificial grassland and promoting the sustainable utilization of artificial grassland have become important tasks that need to be urgently addressed. There have been numerous studies on the effects of monoculture on the soil microbial community structure in artificial grassland, but there is limited research on the effects of mixed sowing on the soil microbial community structure and the related patterns. In this study, Elymus nutans (En), Festuca sinensis (Fs), Avena sativa (As), and Poa pratensis (Pp) were used as common herbage materials in an alpine grassland pastoral area of the eastern Tibetan Plateau. Multi-density monoculture and mixed seeding were employed to establish artificial grassland communities with varying structures. By comparing the soil microbial community structure of the differently treated artificial planting grass, degraded grassland with bald spots, and natural grassland, it was confirmed that plant community diversity significantly influences the microbial community structure. The high-density planting treatment of multiple forage grasses had a more pronounced impact on the soil microbial community structure compared to that of the high-density planting treatment of a single variety of forage grass. The soil microbial community diversity index of the four mixed-planting treatments was higher than those of the other artificial grassland treatments and the natural grassland treatments, and the soil microbial community structure was most similar to that of the natural grassland. Avena sativa planting increased the abundance of Actinobacteria and Basidiomycota and decreased the number of Acidobacteria by increasing the soil pH value. The AFP (As+Fs+Pp) treatment reduced the proportion of Mortierellomycota in the soil by decreasing the content of available phosphorus. The AEFP (As+En+Fs+Pp) treatment increased the number of Proteobacteria by raising the soil total phosphorus content and reduced the abundance of Acidobacteria by lowering the soil pH value. Additionally, a machine learning method was used to evaluate the comprehensive performance of 21 artificial grassland treatments on nine soil physical and chemical properties. It was found that the AEFP mixed-planting and high-density planting treatments had the greatest improvement effect on the nine soil physical and chemical properties, which was conducive to sustainable land use. [ABSTRACT FROM AUTHOR]

Key Laboratory for Ultrafine Materials of Ministry of Education Centre for Biomedical Technologies Current tissue engineering technology aims to achieve the regeneration of human tissues, which integrates the key factors such as scaffolds, cells and biomolecules. Among these key factors, the development of high‐performance scaffolds is the basis for the success of tissue engineering strategies. In the past decades, hydrogel scaffolds have been developed rapidly and widely used in biomedical field, however, their drawbacks have also been revealed, which shows that a single hydrogel scaffold cannot meet the excellent performance required in the field of tissue engineering. Recently, microspheres have been further engineered to fabricate structurally and functionally reliable artificial three‐dimensional scaffolds of desired shape with enhanced specific biological functions. Therefore, the effective combination of hydrogel and microspheres can facilitate the development of high‐performance scaffolds for tissue engineering and further fine‐tuning the composite structure, which is expected to solve the dilemma faced by a single scaffold. In this review paper, we systematically summurized the type and preparation method for synthesis of hydrogel and microsphere materials commonly used in developing microsphere‐containing hydrogel scaffolds. We then reviewed the broad application of these hybrid scaffolds in various fields of tissue engineering, followed by a summary and perspective on future directions. [ABSTRACT FROM AUTHOR]

Helicobacter pylori (H. pylori) is a gram-negative, spiral-shaped bacterium that colonizes the human stomach, leading to various gastric diseases. The efficacy of traditional treatments, such as bismuth-based triple and quadruple therapies, has reduced due to increasing antibiotic resistance and drug toxicity. As a result, the development of effective vaccines was proposed to control H. pylori-induced infections; however, one of the primary challenges is the lack of potent adjuvants. Although various adjuvants, both toxic (e.g. cholera toxin and Escherichia coli heat-labile toxin) and non-toxic (e.g. aluminium and propolis), have been tested for vaccine development, no clinically favourable adjuvants have been identified due to high toxicity, weak immunostimulatory effects, inability to elicit specific immune responses, or latent side effects. Outer membrane vesicles (OMVs), mainly secreted by gram-negative bacteria, have emerged as promising candidates for H. pylori vaccine adjuvants due to their potential applications. OMVs enhance mucosal immunity and Th1 and Th17 cell responses, which have been recognized to have protective effects and guarantee safety and efficacy. The development of an effective vaccine against H. pylori infection is ongoing, with clinical trials expected in the future. [ABSTRACT FROM AUTHOR]

The development of bioactive materials with controllable preparation is of great significance for biomedical engineering. Citric acid-based biomaterials are one of the few bioactive materials with many advantages such as simple synthesis, controllable structure, biocompatibility, biomimetic viscoelastic mechanical behavior, controllable biodegradability, and further functionalization. In this paper, we review the development of multifunctional citrate-based biomaterials for biomedical applications, and summarize their multifunctional properties in terms of physical, chemical, and biological aspects, and finally the applications of citrate-based biomaterials in biomedical engineering, including bone tissue engineering, skin tissue engineering, drug/cell delivery, vascular and neural tissue engineering, and bioimaging.

Coxsackievirus group B3 (CVB3) belongs to the genus Enteroviruses of the family Picornaviridae and is the main pathogen underlying viral myocarditis (VMC). No specific therapeutic is available for this condition. Argininosuccinate synthase 1 (ASS1) is a key enzyme in the urea cycle that converts citrulline and aspartic acid to argininosuccinate. Here, we found that CVB3 and its capsid protein VP2 inhibit the autophagic degradation of ASS1 and that CVB3 consumes citrulline to upregulate ASS1, triggers urea cycle metabolic reprogramming, and then activates macrophages to develop pro-inflammatory polarization, thereby promoting the occurrence and development of VMC. Conversely, citrulline supplementation to prevent depletion can downregulate ASS1, rescue macrophage polarization, and alleviate the pathogenicity of VMC. These findings provide a new perspective on the occurrence and development of VMC, revealing ASS1 as a potential new target for treating this disease., Importance: Viral myocarditis (VMC) is a common and potentially life-threatening myocardial inflammatory disease, most commonly caused by CVB3 infection. So far, the pathogenesis of VMC caused by CVB3 is mainly focused on two aspects: one is the direct myocardial injury caused by a large number of viral replication in the early stage of infection, and the other is the local immune cell infiltration and inflammatory damage of the myocardium in the adaptive immune response stage. There are few studies on the early innate immunity of CVB3 infection in myocardial tissue, but the appearance of macrophages in the early stage of CVB3 infection suggests that they can play a regulatory role as early innate immune response cells in myocardial tissue. Here, we discovered a possible new mechanism of VMC caused by CVB3, revealed new drug targets for anti-CVB3, and discovered the therapeutic potential of citrulline for VMC., Competing Interests: The authors declare no conflict of interest.

Helicobacter pylori causes globally prevalent infections that are highly related to chronic gastritis and even development of gastric carcinomas. With the increase of antibiotic resistance, scientists have begun to search for better vaccine design strategies to eradicate H. pylori colonization. However, while current strategies prefer to formulate vaccines with a single H. pylori antigen, their potential has not yet been fully realized. Outer membrane vesicles (OMVs) are a potential platform since they could deliver multiple antigens. In this study, we engineered three crucial H. pylori antigen proteins (UreB, CagA, and VacA) onto the surface of OMVs derived from Salmonella enterica serovar Typhimurium ( S . Typhimurium) mutant strains using the hemoglobin protease (Hbp) autotransporter system. In various knockout strategies, we found that OMVs isolated from the Δ rfbP Δ fliC Δ fljB Δ ompA mutants could cause distinct increases in immunoglobulin G (IgG) and A (IgA) levels and effectively trigger T helper 1- and 17-biased cellular immune responses, which perform a vital role in protecting against H. pylori . Next, OMVs derived from Δ rfbP Δ fliC Δ fljB Δ ompA mutants were used as a vector to deliver different combinations of H. pylori antigens. The antibody and cytokine levels and challenge experiments in mice model indicated that co-delivering UreB and CagA could protect against H. pylori and antigen-specific T cell responses. In summary, OMVs derived from the S . Typhimurium Δ rfbP Δ fliC Δ fljB Δ ompA mutant strain as the vector while importing H. pylori UreB and CagA as antigenic proteins using the Hbp autotransporter system would greatly benefit controlling H. pylori infection.

The use of membrane-based guided bone regeneration techniques has great potential for single-stage reconstruction of critical-sized bone defects. Here, a multifunctional bone regeneration membrane combining flexible elasticity, electrical stimulation (ES) and osteoinductive activity is developed by in situ doping of MXene 2D nanomaterials with conductive functionality and β-TCP particles into a Poly(lactic acid-carbonate (PDT) composite nano-absorbable membrane (P/T/MXene) via electrostatic spinning technique. The composite membrane has good feasibility due to its temperature sensitivity, elastic memory capacity, coordinated degradation profile and easy preparation process. In vitro experiments showed the P/T/MXene membrane effectively promoted the recruitment and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) under ES and enhanced the angiogenic capacity of endothelial cells, which synergistically promoted bone regeneration through neovascularization. In addition, an in vivo rat model of cranial bone defects further confirmed the bone regeneration efficacy of the P/T/MXene membrane. In conclusion, the developed P/T/MXene membrane can effectively promote bone regeneration through their synergistic multifunctional effects, suggesting the membranes have great potential for guiding tissue regeneration and providing guidance for the biomaterials design., (© 2024 Wiley‐VCH GmbH.)

Biodegradable polymer microspheres that can be used as drug carriers are of great importance in biomedical applications, however, there are still challenges in controllable preparation of microsphere surface morphology and improvement of bioactivity. In this paper, firstly, poly(L-lactic acid) (PLLA) was synthesised by ring-opening polymerisation under anhydrous anaerobic conditions and further combined with the emulsion method, biodegradable PLLA microspheres (PM) with sizes ranging from 60-100 μm and with good sphericity were prepared. In addition, to further improve the surface morphology of PLLA microspheres and enhance their bioactivity, functionalised porous PLLA microspheres loaded with magnesium oxide (MgO)/magnesium carbonate (MgCO 3 ) (PMg) were also prepared by the emulsion method. The results showed that the loading of MgO/MgCO 3 resulted in the formation of a porous structure on the surface of the microspheres (PMg) and the dissolved Mg 2+ could be released slowly during the degradation of microspheres. In vitro cellular experiments demonstrated the good biocompatibility of PM and PMg, while the released Mg 2+ further enhanced the anti-inflammatory effect and osteogenic activity of PMg. Functionalised PMg not only show promise for controlled preparation of drug carriers, but also have translational potential for bone regeneration.

Key Laboratory for Ultrafine Materials of Ministry of Education Centre for Biomedical Technologies Current tissue engineering technology aims to achieve the regeneration of human tissues, which integrates the key factors such as scaffolds, cells and biomolecules. Among these key factors, the development of high-performance scaffolds is the basis for the success of tissue engineering strategies. In the past decades, hydrogel scaffolds have been developed rapidly and widely used in biomedical field, however, their drawbacks have also been revealed, which shows that a single hydrogel scaffold cannot meet the excellent performance required in the field of tissue engineering. Recently, microspheres have been further engineered to fabricate structurally and functionally reliable artificial three-dimensional scaffolds of desired shape with enhanced specific biological functions. Therefore, the effective combination of hydrogel and microspheres can facilitate the development of high-performance scaffolds for tissue engineering and further fine-tuning the composite structure, which is expected to solve the dilemma faced by a single scaffold. In this review paper, we systematically summurized the type and preparation method for synthesis of hydrogel and microsphere materials commonly used in developing microsphere-containing hydrogel scaffolds. We then reviewed the broad application of these hybrid scaffolds in various fields of tissue engineering, followed by a summary and perspective on future directions., (© 2022 Wiley-VCH GmbH.)