Soil organic matter and total nitrogen as key driving factors promoting the assessment of acid-base buffering characteristics in a tea (Camellia sinensis) plantation habitat.

The issue of soil acidification in tea plantations has become a critical concern due to its potential impact on tea quality and plant health. Understanding the factors contributing to soil acidification is essential for implementing effective soil management strategies in tea-growing regions. In this study, a field study was conducted to investigate the effects of tea plantations on soil acidification and the associated acid-base buffering capacity (pHBC). We assessed acidification, pHBC, nutrient concentrations, and cation contents in the top 0-20 cm layer of soil across forty tea gardens of varying stand ages (0-5, 5-10, 10-20, and 20-40 years old) in Anji County, Zhejiang Province, China. The results revealed evident soil acidification due to tea plantation activities, with the lowest soil pH observed in tea gardens aged 10-20 and 20-40 years. Higher levels of soil organic matter (SOM), total nitrogen (TN), Olsen phosphorus (Olsen-P), available iron (Fe), and exchangeable hydrogen (H+) were notably recorded in 10-20 and 20-40 years old tea garden soils, suggesting an increased risk of soil acidification with prolonged tea cultivation. Furthermore, prolonged tea cultivation correlated with increased pHBC, which amplified with tea stand ages. The investigation of the relationship between soil pHBC and various parameters highlighted significant influences from soil pH, SOM, cation exchange capacity, TN, available potassium, Olsen-P, exchangeable acids (including H+ and aluminum), available Fe, and available zinc. Consequently, these findings underscore a substantial risk of soil acidification in tea gardens within the monitored region, with SOM and TN content being key driving factors influencing pHBC.

Ligand Dissociation of Metal-Complex Photocatalysts toward pH-Photomanipulation in Dynamic Covalent Hydrogels for Printing Reprocessable and Recyclable Devices.

Dynamic covalent hydrogels are gaining attention for their potential in smart materials, soft devices, electronics, and more thanks to their impressive mechanical properties, biomimetic structures, and dynamic behavior. However, a significant challenge lies in designing precise and efficient dynamic photochemistry for their preparation, allowing for complex structures and control over the dynamic process. Herein, we propose a general and straightforward orthogonal dynamic covalent photochemistry strategy for preparing high-performance printable dynamic covalent hydrogels, thereby broadening their advanced applications. This photochemical strategy uses a bifunctional photocatalyst to initiate radical polymerization and release ligands through a rapid light-mediated dissociation mechanism. This process leads to a controlled increase in system pH from mildly acidic to alkaline conditions within one hundred seconds, which in turn triggers the pH-sensitive model reactions of boronic acid/diol complexation and Knoevenagel condensation. The orthogonal photochemistry enables the formation of interpenetrated and conjoined networks, significantly enhancing the mechanical properties of the hydrogels. The reversible bonds formed during the process, i.e., boronic ester and unsaturated ketone bonds, confer excellent self-healing, reprocessable, and recyclable properties on the hydrogels through photochemical pH variations. Furthermore, this rapid, controlled fabrication process and dynamic behavior are highly compatible with printing techniques, enabling the design of adaptive and recyclable sensors with different structures. These advancements are promising for various material science, medicine, and engineering applications.

Effect of copper on nitrogen uptake, transportation, assimilation processes, and related gene expression in Chinese cabbage [Brassica campestris L. ssp. Chinensis (L.)] under various nitrate-to-ammonium ratios.

Improving vegetable yield and optimizing its quality through nutrient management have long been central to plant nutrition and horticultural science. Copper (Cu) is recognized as an essential trace element that promotes plant growth and development. However, the mechanisms by which Cu influences nitrogen (N) metabolism remain largely unknown, with limited studies exploring the interaction between Cu and varying nitrate-to-ammonium (nitrate/ammonium) ratios. In this study, Chinese cabbage was exposed to two Cu concentrations (0 and 0.02 mg L-1) in combination with three nitrate/ammonium ratios (10/90, 50/50, and 90/10) under hydroponic conditions. The results showed that Cu application increased plant biomass, nitrate reductase (NR) and glutamine synthetase (GS) enzyme activities, the expression of NR (NIA) and GS2 (Gln2) genes, and N content in both shoots and roots. Additionally, Cu treatment decreased nitrate and free amino acid contents, as well as the expression of nitrate transporters NRT1.1 and NRT2.1 in roots while increasing these four parameters in shoots. Additionally, these effects were significantly modulated by the nitrate/ammonium ratios. In conclusion, Cu may facilitate nitrate transportation, enhance nitrate reduction, promote ammonium assimilation, and influence the transformation of organic N compounds, highlighting its potential role in improving N metabolism in Chinese cabbage.

Grazing alters species relative abundance by affecting plant functional traits in a Tibetan subalpine meadow.

Domestic livestock grazing has caused dramatic changes in plant community composition across the globe. However, the response of plant species abundance in communities subject to grazing has not often been investigated through a functional lens, especially for belowground traits. Grazing directly impacts aboveground plant tissues, but the relationships between above- and belowground traits, and their influence on species abundance are also not well known. We collected plant trait and species relative abundance data in the grazed and nongrazed meadow plant communities in a species-rich subalpine ecosystem of the Qinghai-Tibet Plateau. We measured three aboveground traits (leaf photosynthesis rate, specific leaf area, and maximum height) and five belowground traits (root average diameter, root biomass, specific root length, root tissue density, and specific root area). We tested for shifts in the relationship between species relative abundance and among all measured traits under grazing compared with the nongrazed meadow. We also compared the power of above- and belowground traits to predict species relative abundance. We observed a significant shift from a resource conservation strategy to a resource acquisition strategy. Moreover, this resource conservation versus resource acquisition trade-off can also determine species relative abundance in the grazed and nongrazed plant communities. Specifically, abundant species in the nongrazed meadow had aboveground and belowground traits that are associated with high resource conservation, whereas aboveground and belowground traits that are correlated with high resource acquisition determined species relative abundance in the grazed meadow. However, belowground traits were found to explain more variances in species relative abundance than aboveground traits in the nongrazed meadow, while aboveground and belowground traits had comparable predictive power in the grazed meadow. We show that species relative abundance in both the grazed and the nongrazed meadows can be predicted by both aboveground traits and belowground traits associated with a resource acquisition versus conservation trade-off. More importantly, we show that belowground traits have higher predictive power of species relative abundance than aboveground traits in the nongrazed meadow, whereas in the grazed meadows, above- and belowground traits had comparable high predictive power.

TLR 7/8 agonist reverses oxaliplatin resistance in colorectal cancer via directing the myeloid-derived suppressor cells to tumoricidal M1-macrophages.

Resistance to oxaliplatin is a major obstacle hindering the clinical treatment of colorectal cancer, but the underlying immunological mechanism has not yet been well illustrated. As a pivotal immunosuppressive component in tumor microenvironment, myeloid-derived suppressor cells (MDSCs) and their differentiated tumor-associated macrophages (TAMs) have been considered to be associated with resistance to chemotherapy. The aim of current study was to investigate the role of MDSCs in oxaliplatin-resistance and antitumor activity in colorectal cancer. Here, we found that tumor-bearing mice treated with oxaliplatin performed remarkably decreasing M-MDSCs and M1-type TAMs differentiated from MDSCs in tumor site, which inspired us to combine immunotherapy that activates M1-like TAMs to conquer oxaliplatin resistance. In addition, this study further confirmed a dose-dependent improvement of M1-like macrophage supernatants on enhancing pro-apoptotic effect and inhibiting migration and invasion of cancer cells incubated with oxaliplatin. Administration of oxaliplatin combined with Toll-like receptors agonists R848 reversed the functional orientation of MDSCs towards M1-like macrophages and strengthened antitumor effect of oxaliplatin. In this study, we uncovered novel immunological mechanism of oxaliplatin-resistance and showed the great potential of TLR7/8 agonist as a new immunologic adjuvant in chemotherapy for oxaliplatin-resistant colorectal cancer.

[Mucosal healing in different intestinal segments in patients receiving infliximab treatment for small bowel Crohn's disease].

OBJECTIVE: To evaluate the mucosal healing in the terminal ileum, colon and small bowel in patients receiving infliximab treatment for small bowel Crohn's disease (SBCD). METHODS: The clinical data of 18 patients with SBCD treated with infliximab were analyzed for laboratory findings (routine blood tests, C-reative protein, and albumin), Crohn's disease activity index (CDAI), Lewis score (LS), Crohn's disease simplified endoscopic score (SES-CD) and adverse effects before and after 30 weeks of infliximab treatment. RESULTS: SES-CD, LS, CDAI and CRP were all decreased significantly, but the body mass index and albumin were significantly increased in the 18 patients after 30 weeks of IFX treatment. Sixteen (88.9%) of the patients were in clinical remission, 10 (58.8%) showed terminal ileum and colonic mucosal healing, 4 (22.2%) showed small bowel mucosal healing, and 3 (17.6%) were in deep remission. The 4 patients with small bowel mucosal healing all showed terminal ileum and colon mucosal healing, and 6 patients with terminal ileum and colon mucosal healing did not show small bowel mucosal healing. CONCLUSION: Infliximab treatment can effectively reduce inflammatory activity, induce and maintain clinical remission of SBCD and achieve mucosal healing; small bowel mucosal healing occurs later than terminal ileum and colonic mucosal healing, indicating the importance of small bowel mucosal healing in efficacy analysis of the treatment.