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Keywords = nitrate inhibition

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16 pages, 4979 KB  
Article
Synthesis, Structures and Corrosion Inhibition Properties of 4-Nitrophenylacetato-Rare-Earth(III) 1D Coordination Polymers
by Jacob M. Neill, Naveena Y. Salpadoru Thuppahige, Zhifang Guo, Glen B. Deacon and Peter C. Junk
Molecules 2025, 30(19), 3940; https://doi.org/10.3390/molecules30193940 - 1 Oct 2025
Abstract
The rare earth (RE) aqua 4-nitrophenylacetate (4npa) complexes {[RE(4npa)3(H2O)2]·2H2O}n (RE = La (1La), Nd (2Nd)), [Ce(4npa)3(H2O)2]n (3Ce), and {[RE2(4npa) [...] Read more.
The rare earth (RE) aqua 4-nitrophenylacetate (4npa) complexes {[RE(4npa)3(H2O)2]·2H2O}n (RE = La (1La), Nd (2Nd)), [Ce(4npa)3(H2O)2]n (3Ce), and {[RE2(4npa)6(H2O)]·2H2O}n (RE = Gd (4Gd), Dy (5Dy), Y (6Y), Er (7Er), Yb (8Yb)) were synthesised by salt metathesis reactions of REIII chlorides or nitrates with sodium 4-nitrophenylacetate Na(4npa) in aqueous ethanol. The structures of all the complexes were determined by single-crystal X-ray diffraction (SCXRD) except for RE = 4Gd, which was determined to be isomorphous with the 5Dy and 7Er complexes by X-ray powder diffraction (XRPD). All the complexes crystallise as one-dimensional polymers linked by bridging carboxylates. Complexes (1La3Ce) have mononuclear repeating units with two coordinated waters and ten coordinate RE ions, 1La and 2Nd also have two waters of crystallization, but 3Ce has none. By contrast, complexes (4Gd8Yb) have binuclear repeating units with a single coordinated water. Isomorphous 5Dy and 7Er have one nine coordinate and one eight coordinate metal ion, whilst isomorphous 6Y and 8Yb have two eight coordinate RE ions. In some cases, bulk powders have structures different from the corresponding single crystals. For example, bulk 1La is isomorphous with 3Ce owing to the loss of water of crystallization, and 8Yb exhibits coordination isomerism between single crystals and microcrystalline powder. Weight loss corrosion tests revealed that {[Dy2(4npa)6(H2O)]·2H2O}n (5Dy) has the greatest inhibition efficiency (89%) of the complexes (1La8Yb). The activities are comparable to those of the corresponding 4-hydroxyphenylacetates (4hpa) and far superior to those of 2-hydroxyphenylacetates (2hpa) and the unsubstituted phenylacetates. Whilst the coordination numbers generally decline with the lanthanoid contraction, there are deviations around 5Dy, 6Y, 7Er, and 8Yb, and the corrosion inhibition is optimised with a midrange size. Full article
(This article belongs to the Section Inorganic Chemistry)
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22 pages, 5077 KB  
Article
Restoration of Enzymatic Activity of Energy-Related Proteins in Rats with Traumatic Brain Injury Following Administration of Gamma-Glutamylcysteine Ethyl Ester
by Brittany Rice, Jonathan Overbay, Andrea Sebastian, Patrick G. Sullivan and Tanea T. Reed
Brain Sci. 2025, 15(10), 1067; https://doi.org/10.3390/brainsci15101067 - 30 Sep 2025
Abstract
Background/Objectives: Biochemical processes such as the glycolytic pathway and Kreb’s cycle are important in producing ATP for the brain. Without a sufficient supply of glucose for energy metabolism, the brain cannot efficiently regulate or coordinate the actions and reactions of the body. It [...] Read more.
Background/Objectives: Biochemical processes such as the glycolytic pathway and Kreb’s cycle are important in producing ATP for the brain. Without a sufficient supply of glucose for energy metabolism, the brain cannot efficiently regulate or coordinate the actions and reactions of the body. It is well documented that traumatic brain injury (TBI) is associated with reduced energy metabolism through the production of reactive oxygen/nitrogen species. Antioxidants, such as glutathione (GSH), have been shown to combat the deleterious effects of oxidation by scavenging ROS/RNS, inhibiting propagation, and removing neurotoxic byproducts. Gamma-glutamylcysteine ethyl ester (GCEE), an ethyl ester moiety of gamma-glutamylcysteine, exhibits antioxidant activity by increasing GSH production. This therapeutic has protective effects against oxidative stress through the elevation of glutathione. Methods: This study investigates the enzymatic activities of several key energy-related proteins that have been identified as nitrated in treated Wistar rats with moderate TBI. To test the hypothesis that the elevation of GSH production upon administration of GCEE will normalize enzymatic activity post-TBI, adult male Wistar rats were equally divided into three groups: sham, saline, and GCEE. Rats were treated with 150 mg/kg saline or GCEE at 30 and 60 min post-TBI. Upon sacrifice, brains were harvested and enzymatic activity was measured spectrophotometrically. Results: An increase in enzymatic activity upon GSH elevation via GCEE administration in several key enzymes was observed. Conclusions: GCEE is a potential therapeutic strategy to restore energy-related proteins in the brain post-TBI via GSH elevation. Full article
(This article belongs to the Section Molecular and Cellular Neuroscience)
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21 pages, 2038 KB  
Article
Improving the Yield and Quality of Morchella spp. Using Agricultural Waste
by Jiawen Wang, Weiming Cai, Qunli Jin, Lijun Fan, Zier Guo and Weilin Feng
J. Fungi 2025, 11(10), 703; https://doi.org/10.3390/jof11100703 - 28 Sep 2025
Abstract
Morchella spp. is a type of valuable and rare edible fungi cultivated in soil. Optimization of the cultivation medium for Morchella spp. is key to obtaining high-efficiency production in an ecologically friendly manner. Recently, the sustainable resource utilization of agricultural waste has gathered [...] Read more.
Morchella spp. is a type of valuable and rare edible fungi cultivated in soil. Optimization of the cultivation medium for Morchella spp. is key to obtaining high-efficiency production in an ecologically friendly manner. Recently, the sustainable resource utilization of agricultural waste has gathered attention. Specifically, reusing tomato substrate, mushroom residues, and coconut shells can lower the production costs and reduce environmental pollution, demonstrating remarkable ecological and economic benefits. To determine the soil microbial communities of Morchella spp. using different culture medias and influencing factors, this study analysed the relative abundance of bacterial and fungal communities in natural soil, soil with 5% tomato substrate, soil with 5% mushroom residues, and soil with 5% coconut shells using Illumina NovaSeq high-throughput sequencing. In addition, intergroup differences, soil physiochemical properties, and product quality were also determined. Results demonstrated that agricultural waste consisting of mushroom residues, waste tomato substrate, and coconut shells can improve the efficiency of Morchella spp. cultivation. When considering yield and quality, mushroom residue achieved the highest yield (soil nutrient enrichment), followed by tomato substrate (water holding + grass carbon nutrient). All three types of agricultural waste promoted early fruiting, significantly increased polysaccharide, crude protein, and potassium content, and lowered crude fat and fibre. In regard to soil improvement, the addition of different materials optimized the soil’s physical structure (reducing volume weight and increasing water holding capacity) and chemical properties (enrichment of nitrogen, phosphorus, and potassium, regulating nitrogen and medium trace elements). For microbial regulation, the added materials significantly increased the abundance of beneficial bacteria (e.g., Actinomycetota, Gemmatimonadota and Devosia) and strengthened nitrogen’s fixation/nitration/decomposition functions. In the mushroom residue group, the abundance of Bacillaceae was positively related to yield. Moreover, it inhibited pathogenic fungi like Mortierella and Trichoderma, and lowered fungal diversity to decrease ecological competition. In summary, mushroom residues have nutrient releasing and microbial regulation advantages, while tomato substrate and coconut shells are new high-efficiency resources. These increase yield through the “physiochemical–microorganism” collaborative path. Future applications may include regulating the function of microorganisms and optimizing waste preprocessing technologies to achieve sustainability. Full article
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13 pages, 621 KB  
Article
5-Hydroxymethylfurfural: A Particularly Harmful Molecule Inducing Toxic Lipids and Proteins?
by Joachim Greilberger, Georg Feigl, Matthias Greilberger, Simona Bystrianska and Michaela Greilberger
Molecules 2025, 30(19), 3897; https://doi.org/10.3390/molecules30193897 - 26 Sep 2025
Abstract
Introduction: 5-HMF is a molecule found in carbohydrate-rich foods that is associated not only with cancer and anaphylactic reactions, but also with anti-oxidant properties. Questions arose as to whether 5-HMF exhibited a catalytic effect in relation to lipid peroxidation and lipoprotein oxidation in [...] Read more.
Introduction: 5-HMF is a molecule found in carbohydrate-rich foods that is associated not only with cancer and anaphylactic reactions, but also with anti-oxidant properties. Questions arose as to whether 5-HMF exhibited a catalytic effect in relation to lipid peroxidation and lipoprotein oxidation in presence of metals and/or radicals. Methods: Peroxynitrite (ONOO)-induced chemiluminescence and ONOO nitration of tyrosine residues on BSA using anti-nitro-tyrosine-antibodies were used to measure the protection of 5-HMF against peroxides or nitration compared to vitamin C (VitC). The reductive potential of 5-HMF or VitC on Cu2+ or Fe3 was estimated using the bicinchoninic acid (BCA) or Fenton-complex method. Human plasma was used to measure the generation of malondialdehyde (MDA), 4-hydroxynonenal (HNE), and total thiols after Fe2+/H2O2 oxidation in the presence of different concentrations of 5-HMF or VitC. Finally, Cu2+ oxidation of LDL after 4 h was carried out with 5-HMF or VitC, measuring the concentration of MDA in LDL with the thiobarbituric assay (TBARS). Results: VitC was 4-fold more effective than 5-HMF in scavenging ONOO to nearly 91.5% at 4 mM, with the exception of 0.16 mM, where the reduction of ONOO by VitC was 3.3-fold weaker compared to 0.16 mM 5-HMF. VitC or 5-HMF at a concentration of 6 mM inhibited the nitration of tyrosine residues on BSA to nearly 90% with a similar course. While 5-HMF reduced free Fe3+ in presence of phenanthroline, forming Fe2+ (phenantroleine)3 [Fe2+(phe)3] or complexed Cu2+(BCA)4 to Cu+(BCA)4 weakly, VitC was 7- to 19-fold effective in doing so over all the used concentrations (0–25 mM). A Fe2+—H2O2 solution mixed with human plasma showed a 6–10 times higher optical density (OD) of MDA or HNE in the presence of 5-HMF compared to VitC. The level of thiols was significantly decreased in the presence of higher VitC levels (1 mM: 198.4 ± 7.7 µM; 2 mM: 160.0 ± 13.4 µM) compared to equal 5-HMF amounts (2562 ± 7.8 µM or 242.4 ± 2.5 µM), whereas the usage of lower levels at 0.25 µM 5-HMF resulted in a significant decrease in thiols (272.4 ± 4.0 µM) compared to VitC (312.3 ± 19.7 µM). Both VitC and 5-HMF accelerated copper-mediated oxidation of LDL equally: while the TBARS levels from 4 h oxidized LDL reached 137.7 ± 12.3 nmol/mg, it was 1.7-fold higher using 6 mM VitC (259.9 ± 10.4 nmol/mg) or 6 mM 5-HMF (239.3 ± 10.2 nmol/mg). Conclusions: 5-HMF appeared to have more pro-oxidative potential compared to VitC by causing lipid peroxidation as well as protein oxidation. Full article
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20 pages, 3372 KB  
Article
Characterization and Performance Evaluation of Cotton Fabrics Functionalized via In Situ Green Synthesis of Silver Nanoparticles Using Solanum tuberosum Peel Extract
by Nonsikelelo Sheron Mpofu, Josphat Igadwa Mwasiagi, Cleophas Achisa Mecha and Eric Oyondi Nganyi
Polymers 2025, 17(19), 2598; https://doi.org/10.3390/polym17192598 - 25 Sep 2025
Abstract
The functionalization of textiles with nanomaterials through green synthesis offers a promising pathway for sustainable material innovation. This study explores the in situ green synthesis of silver nanoparticles (AgNPs) onto cotton fabrics using Solanum tuberosum (potato) peel extract as a natural reducing and [...] Read more.
The functionalization of textiles with nanomaterials through green synthesis offers a promising pathway for sustainable material innovation. This study explores the in situ green synthesis of silver nanoparticles (AgNPs) onto cotton fabrics using Solanum tuberosum (potato) peel extract as a natural reducing and stabilizing agent. The synthesis conditions were optimized by varying silver nitrate concentration, extract volume, temperature, pH, and reaction time, after which the optimized protocol was applied for fabric treatment. The presence and distribution of AgNPs were confirmed through UV-Visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy and dynamic light scattering. The treated fabrics demonstrated strong and durable antibacterial performance, with inhibition zones of 23 ± 0.02 against Escherichia coli and 16 ± 0.01 against Staphylococcus aureus. Notably, antibacterial activity was retained even after 20 washing cycles, demonstrating the durability of the treatment. Mechanical testing revealed a 32.25% increase in tensile strength and a corresponding 10.47% reduction in elongation at break compared to untreated fabrics, suggesting improved durability with moderate stiffness. Air permeability decreased by 8.8%, correlating with the rougher surface morphology observed in Scanning Electron Microscopy images. Thermal analysis showed a decrease in thermal stability relative to untreated cotton, highlighting the influence of AgNPs on degradation behavior. Overall, this work demonstrates that potato peel waste, an abundant and underutilized biomass, can be used as a sustainable source for the green synthesis of AgNP-functionalized textiles. The approach provides a cost-effective and environmentally friendly strategy for developing multifunctional fabrics, while supporting circular economy goals in textile engineering. Full article
(This article belongs to the Special Issue Sustainable Electrospinning Processes and Green Solvents)
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17 pages, 2568 KB  
Article
Developing Native Fish to Control Spirogyra in Paddy Fields for Improving the Growth, Nutrient Uptake, and Physiological Characteristics of Oryza sativa L.
by Mei Zhang, Runhai Jiang, Xiaorong Yang, Shaofu Wen, Zexiang Hua, Xiuli Hou and Xuexiu Chang
Agriculture 2025, 15(18), 1990; https://doi.org/10.3390/agriculture15181990 - 22 Sep 2025
Viewed by 209
Abstract
Oryza sativa L. is the largest food crop in the world. The harmful filamentous green algae Spirogyra in paddy fields poses a serious threat to O. sativa yield. Therefore, biological control for Spirogyra is important for sustainable agricultural development. The native fish species [...] Read more.
Oryza sativa L. is the largest food crop in the world. The harmful filamentous green algae Spirogyra in paddy fields poses a serious threat to O. sativa yield. Therefore, biological control for Spirogyra is important for sustainable agricultural development. The native fish species Acrossocheilus yunnanensis can graze on Spirogyra and exhibits strong environmental adaptability, providing a novel approach to the biological control of Spirogyra. Therefore, we designed the O. sativa+Spirogyra+A. yunnanensis co-culture system to study the effects of A. yunnanensis on O. sativa growth and physiological characteristics. The results indicated that Spirogyra stress significantly inhibited O. sativa biomass accumulation, root length and plant height development, reduced photosynthetic efficiency, and increased the contents of oxidative stress markers including malondialdehyde (MDA) and hydrogen peroxide (H2O2). Interestingly, grazing of A. yunnanensis on Spirogyra increased the biomass of Oryza sativa by 58.60%, the root–shoot ratio by 78.01%, and the root length and plant height by 49.83% and 25.85%, respectively. Meanwhile, the soil nitrate nitrogen (NO3-N), ammonium nitrogen (NH4+-N), and available phosphorus (AP) were enhanced, which improved O. sativa nutrient uptake and promoted photosynthetic pigment accumulation. This was manifested by an increase in chlorophyll content, net photosynthetic (Pn), transpiration rate, stomatal conductance (Gs), and intercellular CO2 concentration (Ci). Grazing of A. yunnanensis on Spirogyra alleviated the oxidative damage to O. sativa induced by Spirogyra, as evidenced by decreased malondialdehyde (MDA) and hydrogen peroxide (H2O2) level in both leaves and roots, along with increased protein content. This provides a new strategy for constructing a rice–fish symbiotic system by using indigenous fish species, achieving Spirogyra control and sustainable agricultural development. Full article
(This article belongs to the Section Crop Protection, Diseases, Pests and Weeds)
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23 pages, 2328 KB  
Article
Constructed Wetlands with Novel Substrate Exposed to Nano-Plastics: Mitigating the Effects of Substrate Enzyme and Ecological Processes
by Luming Wang, Juan Huang, Jing Tuo, Jin Xu and Xinwei Li
Toxics 2025, 13(9), 800; https://doi.org/10.3390/toxics13090800 - 20 Sep 2025
Viewed by 287
Abstract
The widespread occurrence of nano-plastics (NPs) in aquatic environments poses emerging challenges to the pollutant removal performance and ecological stability of constructed wetlands (CWs). This study investigates the performance of calcium-modified (Ca-MBF) and manganese-modified basalt fiber (Mn-MBF) bio-nests as novel substrates to mitigate [...] Read more.
The widespread occurrence of nano-plastics (NPs) in aquatic environments poses emerging challenges to the pollutant removal performance and ecological stability of constructed wetlands (CWs). This study investigates the performance of calcium-modified (Ca-MBF) and manganese-modified basalt fiber (Mn-MBF) bio-nests as novel substrates to mitigate NP-induced inhibition of CWs. Laboratory-scale CWs were operated for 180 days to evaluate substrate-associated enzyme activities, microbial community structure, and functional gene profiles. Results showed that Mn-MBF bio-nests enhanced the activities of dehydrogenase (DHA), urease (UR), ammonia monooxygenase (AMO), nitrite oxidoreductase (NOR), nitrate reductase (NAR), nitrite reductase (NIR), and phosphatase (PST) by 86.2%, 65.5%, 127.0%, 62.8%, 131.5%, 65.3%, and 107.0%, respectively, compared with the control. In contrast, Ca-MBF bio-nests increased these enzyme activities by 48.6%, 53.5%, 67.0%, 30.6%, 95.0%, 45.3%, and 54.6%, respectively. MBF bio-nests also enhanced microbial diversity, enriched denitrifying and phosphorus-removing bacteria (e.g., Thauera, Plasticicumulans), and promoted extracellular polymeric substance secretion. Functional gene prediction indicated elevated abundances of nitrogen cycle-related genes, thereby enhancing nitrification, denitrification, and phosphorus removal processes. These synergistic effects collectively improved nitrification, denitrification, and phosphorus removal efficiency, with Mn-MBF showing superior performance. This study highlights MBF bio-nests as a sustainable strategy to enhance the resilience and long-term operational stability of CWs in environments impacted by nano-plastic pollution. Full article
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15 pages, 5799 KB  
Article
New Approaches on Micropropagation of Arracacia xanthorrhiza (“Arracacha”): In Vitro Establishment, Senescence Reduction and Plant Growth Regulators Balance
by Patrick Dias Marques, Thiago Sanches Ornellas, Yohan Fritsche, Ingrilore Flores Mund, Clarissa Alves Caprestano, Valdir Marcos Stefenon, Marcelo F. Pompelli and Miguel Pedro Guerra
Horticulturae 2025, 11(9), 1134; https://doi.org/10.3390/horticulturae11091134 - 18 Sep 2025
Viewed by 342
Abstract
The present study is part of the efforts to develop a micropropagation protocol for Arracacia xanthorrhiza, focusing on improving in vitro establishment, reducing senescence, and balancing plant growth regulators. To control bacterial contamination during culture initiation, ampicillin and tetracycline were tested using [...] Read more.
The present study is part of the efforts to develop a micropropagation protocol for Arracacia xanthorrhiza, focusing on improving in vitro establishment, reducing senescence, and balancing plant growth regulators. To control bacterial contamination during culture initiation, ampicillin and tetracycline were tested using impregnated paper disks. Ampicillin at 100 mg·L−1 achieved 92.4% survival and reduced bacterial contamination to 25.2%, compared to 65.6% in the untreated control, confirming its effectiveness as a low-cost and non-toxic solution. Senescence reduction was evaluated through the addition of activated charcoal and silver nitrate (AgNO3); the latter, at 26 µM, significantly enhanced explant survival, reduced leaf senescence, and promoted shoot and sprout formation. Three plant growth regulators—6-benzylaminopurine (BAP), kinetin (KIN), and meta-topolin (mT)—were tested at multiple concentrations. Meta-topolin at 1 µM produced 3.5 sprouts and 7.2 leaves per plant, demonstrating three times greater biological activity than BAP and optimal morphogenetic response. The integration of antimicrobial control, ethylene inhibition, and cytokinin optimization resulted in a reliable and scalable protocol for A. xanthorrhiza micropropagation. As a concluding remark, these findings provide a practical and efficient framework for clean plant production, with direct applications in conservation, breeding, and commercial propagation of this underutilized Andean crop, while highlighting the need for further validation across genotypes. Full article
(This article belongs to the Section Propagation and Seeds)
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17 pages, 2985 KB  
Article
Corn Stover Biochar Amendment Enhances Nitrogen and Phosphorus Transformations, Microbial Community Diversity, and Enzyme Activities in Agricultural Soil
by Baihui Li, Jie Zhang, Tingting Chang, Qianqian Wu, Hanyu Zheng and Dong Zhang
Plants 2025, 14(17), 2787; https://doi.org/10.3390/plants14172787 - 5 Sep 2025
Viewed by 405
Abstract
Corn stover biochar amendment significantly influences nitrogen (N) and phosphorus (P) transformations, microbial community composition, and enzyme activities in continuous cropping soils. This study aimed to identify the optimal biochar application rate for enhancing N and P nutrient availability in Solanum lycopersicum L. [...] Read more.
Corn stover biochar amendment significantly influences nitrogen (N) and phosphorus (P) transformations, microbial community composition, and enzyme activities in continuous cropping soils. This study aimed to identify the optimal biochar application rate for enhancing N and P nutrient availability in Solanum lycopersicum L. continuous cropping systems, providing theoretical and technical foundations for mitigating continuous cropping obstacles. A soil experiment under rain-out shelters employed four treatments: 1% biochar (BA1), 3% biochar (BA3), 5% biochar (BA5), and a non-amended control (BA0). The results indicated that biochar amendment significantly elevated available phosphorus content in the soil while effectively suppressing its vertical migration; nitrate N content increased under BA1 treatment but decreased in the BA3 and BA5 groups; and the strength of the inhibition effect of biochar treatment on the vertical migration of nitrate N was BA1 > BA5 > BA0 > BA3. The addition of biochar treatment had no significant effect on the content of ammonium N but could inhibit the vertical migration of ammonium N. The addition of biochar treatment could increase the soil’s ammonium N content. The addition of biochar treatment increased soil catalase and urease and sucrase activities, decreased alkaline phosphatase activity, led to the promotion of nitrate reductase activity at low doses and its inhibition at high doses, and resulted in BA1 treatment having the largest soil enzyme index (SEI), which was the most favorable to increase the overall level of soil enzyme activities. Biochar significantly increased the relative abundance of Patescibacteria and Ciliophora while reducing Gemmatimonadota, Acidobacteriota, Nitrospirota, Ascomycota, and Chlorophyta. Comprehensive evaluation using gray relational analysis (GRA) demonstrated that the addition of 5% biochar resulted in the optimal overall performance, enhancing nitrogen and phosphorus transformation, improving microbial community structure, and harmonizing enzyme activities, thereby exhibiting considerable potential for alleviating the nutrient limitations of nitrogen and phosphorus in continuous cropping soils. Full article
(This article belongs to the Special Issue Advances in Microbial Solutions for Sustainable Agriculture)
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19 pages, 1662 KB  
Article
Effects of Roxithromycin Exposure on the Nitrogen Metabolism and Environmental Bacterial Recruitment of Chlorella pyrenoidosa
by Jiping Li, Ying Wang, Zijie Xu, Chenyang Wu, Zixin Zhu, Xingsheng Lyu, Jingjing Li, Xingru Zhang, Yan Wang, Yuming Luo and Wei Li
Plants 2025, 14(17), 2774; https://doi.org/10.3390/plants14172774 - 4 Sep 2025
Viewed by 510
Abstract
The ecotoxicity induced by macrolides has attracted widespread attention, but their impacts on the nitrogen metabolism and symbiotic environmental bacteria of microalgae remain unclear. This study examined the effects of roxithromycin (ROX) on the growth, chlorophyll levels, and nitrogen metabolism of Chlorella pyrenoidosa [...] Read more.
The ecotoxicity induced by macrolides has attracted widespread attention, but their impacts on the nitrogen metabolism and symbiotic environmental bacteria of microalgae remain unclear. This study examined the effects of roxithromycin (ROX) on the growth, chlorophyll levels, and nitrogen metabolism of Chlorella pyrenoidosa; investigated the changes in the composition and functions of environmental bacterial communities; and finally, analyzed the relationship between microalgae and environmental bacteria. The results indicated that all concentrations of ROX (0.1, 0.25, and 1 mg/L) inhibited microalgae growth, but the inhibition rates gradually decreased after a certain exposure period. For instance, the inhibition rate in the 1 mg/L treatment group reached the highest value of 43.43% at 7 d, which then decreased to 18.93% at 21 d. Although the total chlorophyll content was slightly inhibited by 1 mg/L ROX, the Chl-a/Chl-b value increased between 3 and 21 d. The nitrate reductase activities in the three treatments were inhibited at 3 d, but gradually returned to normal levels and even exceeded that of the control group at 21 d. Under ROX treatment, the consumption of NO3 by microalgae corresponded to the nitrate reductase activity, with slower consumption in the early stage and no obvious difference from the control group in the later stage. Overall, the diversity of environmental bacteria did not undergo significant changes, but the abundance of some specific bacteria increased, such as nitrogen-fixing bacteria (unclassified-f-Rhizobiaceae and Mesorhizobium) and organic contaminant-degrading bacteria (Limnobacter, Sphingopyxis, and Aquimonas). The 0.25 and 1 mg/L ROX treatments significantly enhanced the carbohydrate metabolism, cofactor and vitamin metabolism, amino acid metabolism, and energy metabolism of the environmental bacteria, but significantly downregulated nitrogen denitrification. This study provides new insights into the environmental bacteria-driven recovery mechanism of microalgae under antibiotic stress. Full article
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24 pages, 3956 KB  
Article
Impact of Stepwise Salinity Elevation on Nitrogen Removal and Microbial Properties of Morphologically Distinct Anammox Sludge
by Keying Sun, Huining Zhang, Kefeng Zhang, Jianqing Ma, Zhengmin Pan and Shuting Zhang
Water 2025, 17(17), 2611; https://doi.org/10.3390/w17172611 - 3 Sep 2025
Viewed by 900
Abstract
The anaerobic ammonium oxidation (anammox) process offers potential for saline wastewater treatment but is hindered by salt inhibition. This study investigates the salt tolerance mechanisms of granular (R1), biofilm-carrier (R2), and floccular (R3) sludge in up-flow anaerobic sludge blanket (UASB) reactors under 0–20 [...] Read more.
The anaerobic ammonium oxidation (anammox) process offers potential for saline wastewater treatment but is hindered by salt inhibition. This study investigates the salt tolerance mechanisms of granular (R1), biofilm-carrier (R2), and floccular (R3) sludge in up-flow anaerobic sludge blanket (UASB) reactors under 0–20 g/L NaCl. Granular sludge outperformed other biomass types, maintaining >90% ammonia nitrogen (NH4+-N) removal at 20 g/L NaCl due to structural stability and extracellular polymeric substances (EPS) adaptation (shift from hydrophobic proteins to polysaccharides). Microbial analysis revealed a transition from Planctomycetes/Proteobacteria to salt-tolerant Pseudomonadota, with Candidatus_Kuenenia replacing Candidatus_Brocadia as the dominant anaerobic ammonium oxidation bacteria (AnAOB) (reaching 14.5% abundance in R1). Genetic profiling demonstrated coordinated nitrogen metabolism: Hzs/Hdh inhibition (>85%) and NirBD/NrfAH activation (0.23%) elevated NH4+-N, while NarGIV/NapA decline (1.10%→0.58%) increased nitrate nitrogen (NO3-N). NxrB/NirSK maintained low nitrite nitrogen (NO2-N), and GltBD upregulation (0.43%) enhanced osmoregulation. These findings underscore the superior resilience of granular sludge under high salinity, linked to microbial community shifts and metabolic adaptations. This study provides critical insights for optimizing anammox processes in saline environments, emphasizing the importance of biomass morphology and microbial ecology in mitigating salt inhibition. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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14 pages, 9053 KB  
Article
Response of Chaetomium sp. to Nitrogen Input and Its Potential Role in Rhizosphere Enrichment of Lycium barbarum
by Ru Wan, Hezhen Wang, Xiaojie Liang, Xuan Zhou, Yajun Wang, Yehan Tian, Zhigang Shi and Yuekun Li
Microorganisms 2025, 13(8), 1864; https://doi.org/10.3390/microorganisms13081864 - 9 Aug 2025
Viewed by 436
Abstract
Lycium barbarum L. (goji berry), a traditional Chinese medicinal plant, depends heavily on nitrogen input to maintain productivity. Nitrogen application also profoundly influences rhizosphere microbial dynamics, which are critical for soil health and plant performance. This study aimed to investigate how the rhizosphere [...] Read more.
Lycium barbarum L. (goji berry), a traditional Chinese medicinal plant, depends heavily on nitrogen input to maintain productivity. Nitrogen application also profoundly influences rhizosphere microbial dynamics, which are critical for soil health and plant performance. This study aimed to investigate how the rhizosphere fungal community responds to nitrogen input and explore the potential role of beneficial fungi (e.g., Chaetomium) in goji berry rhizosphere enrichment. A field experiment with four nitrogen levels (0, 53.82, 67.62, and 80.73 g·N m−2·year−1, designated as N0, N1, N2, and N3) was conducted to analyze the fungal community structure in the rhizosphere of goji berry using ITS rRNA gene amplicon sequencing. The results showed that nitrogen input significantly altered the rhizosphere fungal community composition and diversity. Redundancy analysis (RDA) and Mantel tests indicated that soil electrical conductivity, total phosphorus, available phosphorus, and nitrate nitrogen were key environmental factors driving the fungal communities’ shifts. Notably, specific fungal genera, including Chaetomium, Cladosporium, Gibberella, Fusarium, Pyxidiophora, Acaulium, and Lophotrichus, exhibited differential enrichment across nitrogen levels. In particular, Chaetomium was significantly enriched under the conventional nitrogen treatment (N2), a strain of Chaetomium sp. LC101 was successfully isolated from the goji berry rhizosphere, and its functional roles were verified via pot experiments. Inoculation with Chaetomium sp. LC101 significantly promoted goji berry growth, with the most pronounced effects observed under N0 treatments, root fresh weight, root vitality, and leaf chlorophyll content increased by up to 55.10%, 15.69%, and 43.27%, respectively, compared to non-inoculated controls. Additionally, Chaetomium sp. LC101 regulated rhizosphere nitrogen transformation by enhancing urease, nitrite reductase, and polyphenol oxidase activities while inhibiting nitrate reductase activity. These findings demonstrate that Chaetomium responds sensitively to nitrogen input, with enrichment under moderate nitrogen levels, and acts as a beneficial rhizosphere fungus by promoting plant growth and regulating nitrogen cycling. This study provides novel insights for nitrogen management in the goji berry industry, where synergistic regulation via “nitrogen reduction combined with microbial inoculation” can reduce nitrogen loss, improve yield and quality through functional fungi, and contribute to ecological sustainability. Full article
(This article belongs to the Section Plant Microbe Interactions)
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16 pages, 1592 KB  
Article
Differential Responses of Rice Genotypes to Nitrogen Supply: Impacts on Nitrogen Metabolism and Chlorophyll Fluorescence Kinetics
by Zexin Qi, Wenzheng Sun, Chun Luo, Qiang Zhang, Feisal Mohamed Osman, Chenglong Guan, Ye Wang, Mengru Zhang, Xiaotong Zhang, Jiale Ding, Yuankai Zhang, Fenglou Ling, Xiaolong Liu, Zhian Zhang and Chen Xu
Plants 2025, 14(16), 2467; https://doi.org/10.3390/plants14162467 - 8 Aug 2025
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Abstract
Nitrogen (N) availability significantly influences plant metabolism and productivity. The aim of this study was to assess the effects of low N stress and subsequent N supplementation on key enzymes of nitrogen metabolism, nitrogen metabolism-related substances, and chlorophyll a fluorescence kinetic parameters in [...] Read more.
Nitrogen (N) availability significantly influences plant metabolism and productivity. The aim of this study was to assess the effects of low N stress and subsequent N supplementation on key enzymes of nitrogen metabolism, nitrogen metabolism-related substances, and chlorophyll a fluorescence kinetic parameters in rice genotypes with different nitrogen utilization efficiencies. We used the Jijing 88 (low-N tolerant) and Xinong 999 (low-N sensitive) as test materials. During the seedling, tillering, and booting stages, the 1/2N and 1/4N treatments were restored to the 1N treatment level. Nine treatments were used in this experiment: CK (1N), A1 (1/2N), A2 (1/2N restored to 1N during the seedling stage), A3 (1/2N restored to 1N during the tillering stage), A4 (1/2N restored to 1N during the booting stage), B1 (1/4N), B2 (1/4N restored to 1N during the seedling stage), B3 (1/4N restored to 1N during the tillering stage), and B4 (1/4N restored to 1N during the booting stage). Key physiological responses, nitrogen compounds, enzymes activities, and chlorophyll a fluorescence kinetics were analyzed. Under low nitrogen conditions, the growth and nitrogen assimilation of rice were inhibited. Compared to XN 999, JJ 88 maintains higher levels of dry matter, nitrate reductase activity (NR), glutamine synthetase activity (GS), glutamate oxaloacetate transaminase activity (GOT), glutamate pyruvate transaminase activity (GPT), as well as nitrate (NO3) and ammonium (NH4+) nitrogen contents. After N supplementation during the early growth stage, both JJ 88 and XN 999 exhibit recovery capabilities. However, in the late growth stage, JJ 88 demonstrates superior recovery capabilities. In addition to enhancing nitrogen metabolism levels, there is also an increase in the content of osmotic regulation substances such as soluble sugars, free amino acids, and proline, along with responses in chlorophyll fluorescence kinetic parameters. This was primarily manifested in the enhancement of performance index (PIABS, PItotal), and quantum yield (φEO, φRO, ψEO), which maintain photosynthetic performance and electron transport efficiency. The research findings indicated that reducing N supply during the early growth stage and restoring N levels in the later stage are beneficial for the recovery of low-nitrogen-tolerant rice varieties. Therefore, in the context of sustainable agricultural production, the breeding of low-nitrogen-tolerant rice varieties and the optimization of N fertilizer management are crucial. Full article
(This article belongs to the Special Issue Advances in Nitrogen Nutrition in Plants)
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24 pages, 3924 KB  
Article
Effects of Zinc-Layered Filler Incorporation Routes on the Antimicrobial, Mechanical, and Physical Properties of Calcium Caseinate Biopolymeric Films
by Maria E. Becerra, Reynell Pérez-Blanco, Oscar Giraldo, Lucia Medina-Pimentel and Christhy V. Ruiz
Molecules 2025, 30(15), 3307; https://doi.org/10.3390/molecules30153307 - 7 Aug 2025
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Abstract
As the demand for sustainable materials continues to grow, calcium caseinate (Cas) biopolymer films have emerged as promising alternatives to fossil-based plastics. However, their mechanical fragility and high-water sensitivity limit their application in packaging. In this study, we reinforced Cas films with zinc [...] Read more.
As the demand for sustainable materials continues to grow, calcium caseinate (Cas) biopolymer films have emerged as promising alternatives to fossil-based plastics. However, their mechanical fragility and high-water sensitivity limit their application in packaging. In this study, we reinforced Cas films with zinc hydroxide nitrate (ZHN) using two incorporation methods: wet (ZHN-w) and dry (ZHN-d). We evaluated how each method affected the dispersion of the filler and, consequently, the functional properties of the films. To our knowledge, this is the first report of ZHN being used in biopolymeric films. Structural and morphological analyses showed better dispersion of ZHN in the wet-incorporated films. These samples exhibited a substantial increase in tensile strength, from 0.75 ± 0.00 MPa to 9.62 ± 2.45 MPa, along with a marked improvement in Young’s modulus. The films also became less soluble in water, more resistant to swelling, and structurally more cohesive. In antimicrobial tests, the ZHN-w films showed stronger inhibition against E. coli and S. aureus. Overall, this approach offers a simple and effective way to enhance protein-based films using food-safe materials, making them suitable for active and bio-based packaging applications. Full article
(This article belongs to the Section Materials Chemistry)
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21 pages, 1980 KB  
Article
Organic Manure with Chemical Fertilizers Improves Rice Productivity and Decreases N2O Emissions by Increasing Soil Nitrogen Sequestration
by Yiren Liu, Jingshang Xiao, Xianjin Lan, Jianhua Ji, Hongqian Hou, Liumeng Chen and Zhenzhen Lv
Agronomy 2025, 15(8), 1783; https://doi.org/10.3390/agronomy15081783 - 24 Jul 2025
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Abstract
Soil organic nitrogen (SON) positively influences crop productivity, greenhouse gas (GHG) emissions, and sustained nitrogen (N) supply. Herein, we observed the effect of different treatments; no fertilizers (CK), chemical fertilizers (nitrogen, phosphorus, and potassium (NPK)), organic manure, and NPK + OM (NPKOM). This [...] Read more.
Soil organic nitrogen (SON) positively influences crop productivity, greenhouse gas (GHG) emissions, and sustained nitrogen (N) supply. Herein, we observed the effect of different treatments; no fertilizers (CK), chemical fertilizers (nitrogen, phosphorus, and potassium (NPK)), organic manure, and NPK + OM (NPKOM). This study was performed in a randomized complete block design (RCBD) with three replications. The results indicated that NPKOM treatment significantly decreased the nitrous oxide (N2O) emissions by 19.97% and 17.47% compared to NPK in both years. This was linked with improved soil nutrient availability, soil organic carbon, soil organic nitrogen (SON) storage (10.06% and 12.38%), SON sequestration (150% and 140%), increased soil particulate (44.11% and 44%), and mineral-associated organic N (26.98% and 26.47%) availability. Furthermore, NPKOM also enhanced nitrate reductase (NR: 130% and 112%), glutamine synthetase (GS: 93% and 88%), sucrose phosphate synthase (SPS: 79% and 98%), SSs (synthetic direction; 57% and 50%), and decreased SSs activity in the decomposition direction (18% and 21%). This, in turn, inhibited the decomposition of sucrase and enhanced starch conversion into carbohydrates, thus leading to an increase in rice yield and a decrease in N2O emissions. All fertilizations, particularly NPKOM, significantly enhanced grain protein contents by increasing N uptake and its availability. Therefore, NPKOM is an effective practice to enhance rice productivity, and SON sequestration and mitigate the N2O emissions and subsequent climate change. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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