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1. Copper oxide nanoparticle dissolution at alkaline pH is controlled by dissolved organic matter: influence of soil-derived organic matter, wheat, bacteria, and nanoparticle coating

   https://doi.org/10.1039/d0en00574f  

   Hortin, J. M.; Anderson, A. J.; Britt, D. W.; Jacobson, A. R.; McLean, J. E. (January 2020, Environmental Science: Nano)

   Dissolution of CuO nanoparticles, releasing Cu ions, is a primary mechanism of Cu interaction in the rooting zone of plants. CuO dissolution is sometimes incorrectly considered negligible at high pH, since complexation of Cu with dissolved organic matter may enhance nanoparticle dissolution. Therefore data on the effects of plant-microbial-soil interactions on nanoparticle dissolution, particularly in alkaline soils, are needed. Dissolution of CuO nanoparticles (100 mg kg −1 Cu) was studied in sand supplemented with factorial combinations of wheat growth, a root-colonizing bacterium, and saturated paste extracts (SPEs) from three alkaline, calcareous soils. In control sand systems with 3.34 mM Ca(NO 3 ) 2 solution, dissolved Cu was low (266 μg L −1 Cu). Addition of dissolved organic matter via wheat root metabolites and/or soil SPEs increased dissolved Cu to 795–6250 μg L −1 Cu. Dissolution was correlated with dissolved organic carbon ( R = 0.916, p < 0.0001). Ligands >3 kDa, presumably fulvic acid from the SPEs, complexed Cu driving solubility; the addition of plant exudates further increased solubility 1.5–3.5×. The root-colonizing bacterium decreased dissolved Cu in sand pore waters from planted systems due to metabolism of root exudates. Batch solubility studies (10 mg L −1 Cu) with the soil SPEs and defined solutions containing bicarbonate or fulvic acid confirmed elevated CuO nanoparticle solubility at >7.5 pH. Nanoparticle dissolution was suppressed in batch experiments compared to sand, via nanoparticle organic matter coating or homoconjugation of dissolved organic matter. Alterations of CuO nanoparticles by soil organic matter, plant exudates, and bacteria will affect dissolution and bioavailability of the CuO nanoparticles in alkaline soils. 

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2. Soil-derived fulvic acid and root exudates, modified by soil bacteria, alter CuO nanoparticle-induced root stunting of wheat via Cu complexation

   https://doi.org/10.1039/c9en00728h  

   Hortin, J. M.; Anderson, A. J.; Britt, D. W.; Jacobson, A. R.; McLean, J. E. (December 2019, Environmental Science: Nano)

   CuO nanoparticles (NPs) are explored as fungicides and fertilizers, and are increasingly likely to be applied to agricultural soils. Consequently, interactions of CuO NPs with soil pore water (SPW) components, plants, and microbes must be understood. These experiments examined whether dissolved natural organic matter (DNOM) from SPW, or root/bacterial exudates, changed wheat ( Triticum aestivum L. v. Deloris) responses to 100 mg kg −1 (Cu/sand) as CuO NPs. Seedlings were grown in sand with 3.34 mM Ca(NO 3 ) 2 or one of three SPWs, differing in DNOM concentration and composition. At 10 days post-germination, CuO NPs stunted roots by 59% in the 3.34 mM Ca(NO 3 ) 2 and 26–35% in the three SPWs compared to plants grown without NPs. Malate, citrate, gluconate, and 2′-deoxymugineic acid (DMA), were elevated 1.3 to 5-fold in the rhizosphere with CuO NPs present. Cu was bioavailable through metallo-organic complexes, including Cu–DMA and Cu–gluconate. Fulvic acid in SPWs mitigated CuO NP-induced wheat root shortening. Pseudomonas chlororaphis O6 eliminated malate and citrate in the rhizospheres, reduced rhizosphere dissolved Cu ∼18–66%, and reduced root Cu 39% across all SPWs while enhancing root stunting ∼17% more across all SPWs than non-inoculated wheat grown with CuO NPs. Thus, both SPW components and root microbial colonization influenced wheat responses to CuO NPs. These interactions are likely in agricultural soils with additional processes, such as ion sorption, to influence CuO NP phytotoxicity, highlighting the importance of considering not just the target plant, but soil properties and associated microbiomes when evaluating impacts of NPs in agricultural usage. 

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3. Advanced material modulation of nutritional and phytohormone status alleviates damage from soybean sudden death syndrome

   https://doi.org/10.1038/s41565-020-00776-1  

   Ma, Chuanxin; Borgatta, Jaya; Hudson, Blake Geoffrey; Tamijani, Ali Abbaspour; De La Torre-Roche, Roberto; Zuverza-Mena, Nubia; Shen, Yu; Elmer, Wade; Xing, Baoshan; Mason, Sara Elizabeth; et al (October 2020, Nature nanotechnology)

   Customized Cu3(PO4)2 and CuO nanosheets and commercial CuO nanoparticles were investigated for micronutrient delivery and suppression of soybean sudden death syndrome. An ab initio thermodynamics approach modelled how material morphology and matrix effects control the nutrient release. Infection reduced the biomass and photosynthesis by 70.3 and 60%, respectively; the foliar application of nanoscale Cu reversed this damage. Disease-induced changes in the antioxidant enzyme activity and fatty acid profile were also alleviated by Cu amendment. The transcription of two dozen defence- and health-related genes correlates a nanoscale Cu-enhanced innate disease response to reduced pathogenicity and increased growth. Cu-based nanosheets exhibited a greater disease suppression than that of CuO nanoparticles due to a greater leaf surface affinity and Cu dissolution, as determined computationally and experimentally. The findings highlight the importance and tunability of nanomaterial properties, such as morphology, composition and dissolution. The early seedling foliar application of nanoscale Cu to modulate nutrition and enhance immunity offers a great potential for sustainable agriculture. 

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4. Biochemical changes and phytoextraction potential of quinoa and wheat for their resilience to salt stress

   https://doi.org/10.1038/s41598-025-17012-2  

   Hosseini, Sepideh; Moogouei, Roxana; Teymoori, Shahla; Moogouei, Roshanak; Borghei, Mehdi; Latinwo, Ololade; Katam, Keyura (December 2025, Scientific Reports)

   Phytoextraction presents a promising alternative for desalinating saline environments. Our study investigated the phytoremediation efficiency and ion uptake mechanisms of Chenopodium quinoa (Quinoa) and Triticum aestivum (wheat) in response to salt stress. The plants were subjected to NaCl-induced salinity levels of 5, 10, and 15 dS m⁻1 in a hydroponic system, and we measured the remediation efficiency for sodium, potassium, calcium, magnesium, and chloride ions. The solutions incubated with wheat plants exhibited higher ion concentrations than those with quinoa. Chenopodium showed significantly higher bioaccumulation of ions (Mg2⁺, Ca2⁺, Na⁺, Cl⁻, K⁺) in its roots and leaves compared to Triticum. Chenopodium demonstrated greater ion uptake efficiency than Triticum. Under control conditions, both plants effectively contributed to desalination, as indicated by their translocation factor values. In contrast, Chenopodium showed higher TF under salt stress than Triticum for the measured ions. Salinity did not significantly affect potassium accumulation in quinoa shoots, which helped maintain membrane integrity compared to wheat. The analysis of the oxidative status revealed that wheat accumulated higher levels of hydrogen peroxide and lipid peroxidation, especially in the roots. The activities of antioxidative enzymes superoxide dismutase, peroxidase, catalase, ascorbic peroxidase, and glutathione reductase showed a significant increase in the roots and leaves of Chenopodium under salt stress, providing essential protection against reactive oxygen species and lipid peroxidation. Additionally, the increase in leaf area and dry weight in quinoa indicates a more significant accumulation of ions at higher concentrations, demonstrating its superior phytoremediation efficiency compared to wheat 

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5. Plasma Metabolomics in a Nonhuman Primate Model of Abdominal Radiation Exposure

   https://doi.org/10.3390/metabo11080540  

   Jun, Se-Ran; Boerma, Marjan; Udaondo, Zulema; Richardson, Sasha; Thrall, Karla D.; Miousse, Isabelle R.; Seng, John; Pathak, Rupak; Hauer-Jensen, Martin (August 2021, Metabolites)

   The acute radiation syndrome is defined in large part by radiation injury in the hematopoietic and gastrointestinal (GI) systems. To identify new pathways involved in radiation-induced GI injury, this study assessed dose- and time-dependent changes in plasma metabolites in a nonhuman primate model of whole abdominal irradiation. Male and female adult Rhesus monkeys were exposed to 6 MV photons to the abdomen at doses ranging between 8 and 14 Gy. At time points from 1 to 60 days after irradiation, plasma samples were collected and subjected to untargeted metabolomics. With the limited sample size of females, different discovery times after irradiation between males and females were observed in metabolomics pattern. Detailed analyses are restricted to only males for the discovery power. Radiation caused an increase in fatty acid oxidation and circulating levels of corticosteroids which may be an indication of physiological stress, and amino acids, indicative of a cellular repair response. The largest changes were observed at days 9 and 10 post-irradiation, with most returning to baseline at day 30. In addition, dysregulated metabolites involved in amino acid pathways, which might indicate changes in the microbiome, were detected. In conclusion, abdominal irradiation in a nonhuman primate model caused a plasma metabolome profile indicative of GI injury. These results point to pathways that may be targeted for intervention or used as early indicators of GI radiation injury. Moreover, our results suggest that effects are sex-specific and that interventions may need to be tailored accordingly. 

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