Phosphate Source Research Articles

Phosphate-solubilizing fungus (PSF) - mediated phosphorous solubilization and validation through Artificial intelligence computation.

Phosphate-solubilizing fungus (PSF) strain alaromyces funiculosus was investigated for phosphorus solubilization, utilizing a range of pH levels and phosphate sources, followed by data confirmation through artificial intelligence modeling. T. funiculosus strain was exposed to five different phosphate sources [Ca3(PO4)2, FePO4, CaHPO4, AlPO4, and phytin] at different pH levels (4.5, 5.5, 6.5, 7.0, and 7.5). ANOVA, Pareto charts, and normal plots were used for analyzing the data. Artificial intelligence-based multilayer perceptron (MLP), random forest (RF) and extreme gradient boosting (XGBoost) models were used for data validation and prediction. Five-fold more phosphate (P) solubility by T. funiculosus was registered as compared to the control. The maximum soluble P was found at pH 4.5 (318324 ppb) and CaHPO4 (444045 ppb). Combination of phytin × 4.5 pH yielded the highest dissolved phosphorus (1537988 ppb), followed by 127458 ppb from the control × 4.5 pH. Pareto chart and normal plot analysis showedthe negative impact of pH (B), pH × F/C (fungus/control) × P-Source (ABC), and F/C (A) factor. Whereas pH × P-Source (AC) and P-Source (C) has positive impact on P solubility. The maximum R2 scores showed the order of RF (0.944) > MLP (0.938) > XGBoost (0.899). T. funiculosus strain has a grain potential for sustainable use for different types of phosphate sources. Application AI/ML models based on different performance metrics predicted the validated the attained results. In future research, it is recommended to check the efficacy of developed strategy under field conditions and to check the impact on soil and plant.

Amending clayey and sandy soils with nano - bio phosphorous for regulating tomato growth, biochemical, and physiological characteristics

Phosphorus is a critical nutrient that significantly enhances tomato production, so maintaining an adequate level of phosphorus plays an essential role in enhancing the growth of tomato by being present in the soil. This study assessed the impact of soil texture and phosphorus content on tomato plant properties using a factorial, complete, randomized design with four replications. Treatments included clayey and sandy soils with varying phosphorus sources: non-phosphorus (P0), calcium phosphate (CaP1 and CaP2), and nano-hydroxyapatite (PN1 and PN2), where 1 indicates a concentration of 0.12 g and 2 indicates a concentration of 0.23 g per 5-kilogram pot of fertilizer. Results indicated that treatments significantly influenced yield parameters such as average fruit weight, juice content, antioxidant activity, and fruit volume. In the clayey soil, CaP2 treatment had a superior effect on yield, average fruit weight, and shoot fresh weight. In comparison with sandy conditions, CaP2 produced a 50% increase in fruit number, 29% increase in average fruit weight, and 91% increase in fruit yield. The treatments then impacted the shoot fresh weight and root length, while the phosphorus concentration appeared to be more dependent on soil type than on phosphorus sources. Similar to the CaP1 and CaP2 treatments, the PN1 treatment in clay soil also resulted in the highest fresh and dry weights of tomato shoots when compared with the control group. Generally, the findings from this study suggest that the use of CaP2 can serve as a reliable method to improve the growth, yield, and fruit quality of tomatoes, especially in clayey soil environments. However, nano-based phosphorous sources need to be tested more to see if they can improve tomato performance in a range of soil conditions. Also, further research should look into the long-term effects of phosphorous interventions on soil health and sustainability.

Exploring the antimicrobial activity of hydrothermally synthesized copper pyrophosphate nanoflakes

In recent years, infections and the escalating resistance to antimicrobial drugs have emerged as significant health concerns. Due to their remarkable effectiveness and minimal potential for bacteria to develop resistance, copper-based nanomaterials are being considered as prospective alternatives to conventional antibiotics. In this study, copper pyrophosphate nanoflakes were synthesized using a simple hydrothermal technique with an inorganic phosphate source. These nanoflakes, characterized by a high aspect ratio, exert a substantial impact on bacterial cell walls, effectively eliminating microbial pathogens. X-ray diffraction (XRD) analysis confirmed the monoclinic phase of the copper pyrophosphate nanomaterial, while the band gap energy of 2.7 eV was estimated from the Tauc plot. Additionally, the antimicrobial efficacy of Cu2P2O7 was evaluated against various gram-negative, gram-positive, and fungal pathogens at different concentrations. Notably, all tested bacterial strains exhibited moderate antimicrobial effects at concentrations of 5 mg/mL. For instance, S. aureus and E. coli displayed a 13 mm zone of inhibition, demonstrating excellent activity and lower cytotoxicity. These findings underscore the potential of Cu2P2O7 as a promising candidate for the development of novel drugs targeting pathogenic bacteria affecting human health.

The Isotopic Composition of Selected Phosphate Sources (δ18O-PO4) from the Area of the Vistula and Bug Interfluve (Poland)

Phosphorus belongs to the crucial bioelements that cause eutrophication, and phosphates, easily assimilated by organisms, are widespread in the environment. Phosphates can be of natural or anthropogenic origin and can derive from various point or non-point sources. Knowledge about the origin of nutrients is necessary to effectively manage, protect, and revitalize water resources. To recognize various phosphate sources in the study area of our research, i.e., the Vistula and Bug interfluve (SE Poland), we used the oxygen isotopic signature of phosphate ions (δ18O-PO4), which has been successfully used in recent decades as a tracer of phosphorus cycling in water studies. We measured the δ18O-PO4 of dissolved inorganic phosphates (DIPs) extracted from various phosphate sources. The obtained results are as follows: For springs, the δ18O-PO4 value varied from +14.8‰ to +18.5‰; for riverine samples, from +10.3‰ to +18.6‰, which were significantly location-dependent; while waste water treatment plant effluents ranged from +12.4‰ to +15.6‰. Two tested drainage water samples had similar isotopic compositions (+16.7‰ and +17.3‰). In the case of two analyzed bedrock samples, the δ18O-PO4 values, which were similar (+20.5‰ and +21.7‰), are close to the existing data on sedimentary bedrocks derived from similar geological periods. The obtained results can be helpful in future research aimed at identifying phosphate sources and P cycling in the studied area.

Valorization potentials of phosphate tailings at Minjingu mines in Northern Tanzania

Sedimentary and igneous rocks are the two primary sources of phosphate that are mined and beneficiated to fertilizer. During the beneficiation process, phosphate is lost into the tailings. We investigated phosphate concentrations in tailings dumps at Minjingu mine, Tanzania using energy-dispersive X-ray fluorescence spectrometry to quantify the chemical compositions. The phosphate content in the tailings varied from 12.91% phosphorus pentoxide (P2O5) in Tailings 2 to 19.61% in Tailings Dump 1. The naturally occurring phosphate concentration in rocks ranges from 3% to 35%, and phosphate tailings from various locations with P2O5 concentrations as low as 6.46-12.65% have been beneficiated to commercial fertilizer. Our investigation revealed that phosphate concentrations in Minjingu tailings may be sufficient to be recovered for commercial applications. Suitable recovery methods are discussed, and we recommend that beneficiation should be performed to minimize the loss of phosphate into tailings. Further research is needed to identify the optimal beneficiation methodology.

Influence of altered freshwater discharge on the seasonality of nutrient distributions near La Grande River, northeastern James Bay, Québec

In subarctic marine environments, nutrient stocks are replenished through physical and biogeochemical processes in winter, largely setting an upper limit on new primary production for the next growing season. In spring, marine nutrient stocks are modified by freshwater-associated additions, especially in coastal areas. Hydroelectric development of the La Grande River (LGR) in northern Québec has shifted the timing of peak freshwater discharge from spring into winter, producing 10 times the natural winter discharge. Here, we considered salinity, oxygen isotope ratio (δ18O), and nutrient (nitrate, phosphate) data from coastal waters of northeast James Bay in different seasons of 2016 and 2017. We quantified two main freshwater sources, LGR and sea-ice melt, established by freshwater tracers, and their influence on coastal nutrient distributions. Our results show that LGR is the dominant source of freshwater to coastal waters throughout the year, especially during winter, and an important source of nitrate to nitrogen-limited coastal waters (winter concentrations of 4.53 μM versus 3.18 μM in ambient seawater). Despite being a poor phosphate source (0.11 μM versus 0.66 μM in ambient seawater), LGR provides the largest portion of the phosphate stock in surface waters near its mouth. LGR regulation has changed the pattern of natural fluvial nitrate inputs: what was observed in spring (pre-development) is now observed in winter (post-development). Thus, high winter surface nitrate stocks (22.5 mmol m−2) are available to support primary production, but are dispersed to offshore areas prior to the onset of the growing season, which begins only after the return of light. In northeast James Bay, the timing and magnitude of primary production, dependent on nutrients in the water column, is expected to have been impacted by altered freshwater input, reducing overall production in local areas and potentially increasing production further downstream with cascading effects on the marine ecosystem.

Phosphorus availability from olivine for biospheres

Phosphorus plays a multifaceted role for all known life and hence understanding its sources on the early Earth provides constraints on how life developed to incorporate this element into its biochemistry. Currently, the major phosphorus mineral group on the surface of the Earth are the apatites, which are poorly soluble calcium phosphates and hence may not have been a good source of phosphorus on the early Earth. An alternative source of phosphorus may be the mineral olivine. Given that olivine makes up a large part of the upper mantle of Earth and presumably other rocky planets and moons, it stands to reason that olivine may be a potential phosphorus reservoir for prebiotic chemical environments. Here we examine the phosphorus content of 10 olivine samples from different terrestrial localities to determine their P content and P speciation. We find that extracts of the samples contain varying amounts of phosphate, and some contain pyrophosphate. Olivine may have served as a source of phosphate on the early Earth and possibly elsewhere in the solar system, and its dissolution could have supplied this nutrient to a nascent biosphere.

Dietary Needs, Barriers, and Facilitators Among Patients on Hemodialysis and Their Caregivers: The GoodRENal Project in Spain

ObjectiveDietary restrictions are common in patients undergoing hemodialysis (HD). These restrictions result in a complex diet that becomes difficult for patients to understand and to follow. Therefore, we aimed to identify dietary needs, and barriers and facilitators that influence the adherence to dietary recommendations as perceived by patients on HD and their caregivers. MethodsSeventy-two Spanish patients on HD and fifty-seven caregivers participated in this explorative study by replying a questionnaire consisting of 20 and 10 questions respectively. The responses were assessed using a Likert scale varying from 1 to 5 (strongly agree, agree, neither disagree or disagree, disagree, strongly disagree, respectively) to evaluate the perception of patients and caregivers regarding dietary needs, barriers and facilitators to adhere to the recommended diet. For analysis purposes, the responses were grouped in three categories (agree, neither agree or disagree, disagree). ResultsSeventy percent of the patients agreed that knowing the food sources of potassium, protein and phosphate was a need for them to know to be able to adhere to the dietary recommendations. Moreover, patients stated that not being able to eat what they liked, and feeling thirsty, were important barriers. For caregivers, the support of a renal dietitian was mentioned as an important facilitator to assist those they cared for to adhere to the diet. ConclusionsKnowing food sources of potassium, phosphate, and protein, exploring foods patients like to eat and adjusting fluid intake to avoid feeling thirsty were identified as important by the patients. These findings can be used to develop strategies and educational material to improve the dietary adherence in patients undergoing HD. Moreover, the presence of a renal dietitian was identified as an important resource by the caregivers.

Chemical genetic analysis of enoxolone inhibition of Clostridioides difficile toxin production reveals adenine deaminase and ATP synthase as antivirulence targets

Toxins TcdA and TcdB are the main virulence factors of Clostridioides difficile, a leading cause of hospital-acquired diarrhea. Despite their importance, there is a significant knowledge gap of druggable targets for inhibiting toxin production. To address this, we screened non-antibiotic phytochemicals to identify potential chemical genetic probes to discover anti-virulence drug targets. This led to the identification of 18β-glycyrrhetinic acid (enoxolone), a licorice metabolite, as an inhibitor of TcdA and TcdB biosynthesis. Using affinity-based proteomics, potential targets were identified as ATP synthase subunit alpha (AtpA) and adenine deaminase (Ade, which catalyzes conversion of adenine to hypoxanthine in the purine salvage pathway). To validate these targets, a multi-faceted approach was adopted. Gene silencing of ade and atpA inhibited toxin biosynthesis, while SPR and ITC molecular interaction analyses revealed direct binding of enoxolone to Ade. Metabolomics demonstrated enoxolone induced the accumulation of adenosine, while depleting hypoxanthine and ATP in C. difficile. Transcriptomics further revealed enoxolone dysregulated phosphate uptake genes, which correlated with reduced cellular phosphate levels. These findings suggest that enoxolone's cellular action is multi-targeted. Accordingly, supplementation with both hypoxanthine and triethyl phosphate (TEP), a phosphate source, was required to fully restore toxin production in the presence of enoxolone. In conclusion, through the characterization of enoxolone, we identified promising anti-virulence targets that interfere with nucleotide salvage and ATP synthesis, which may also block toxin biosynthesis.

Preparation and Characterization of Hydroxyapatite Using Precursor Extracted from Cockle Shell Waste

Hydroxyapatite (HAP) is a widely used biomaterial due to its excellent bioactivity, biocompatibility, and structural similarity to the mineral component of human bone and teeth. However, the synthesis of HAP typically relies on expensive and non-renewable precursors, which can limit its widespread applications. This study investigates the extraction and purification of HAP from cockle shells, which are a readily available and renewable source of calcium carbonate. The extraction and purification of hydroxyapatite (HAP) from cockle shells, which are rich in calcium carbonate, is a promising method for producing HAP for biomedical applications due to its bioactivity and biocompatibility. This study investigates the use of a calcination process and wet slurry precipitation technique to produce HAP from seashells, focusing on the effect of reaction time of phosphate source (KH2PO4) and calcium oxide (CaO) on HAP production. EDX reported Ca/P ratio of 1.61 for HAP synthesized by chemical precipitation for 2 hours of reaction. Meanwhile, the XRD results indicate that a 4-hour reaction time produces more crystalline HAP than shorter reaction times, highlighting the importance of reaction time in HAP synthesis. This research demonstrates the potential of utilizing seashell waste as a valuable natural resource for applications in healthcare and waste management.

Magnesium recovery from brackish water desalination brine and valorization in fertilizer production

The generated brine from the desalination unit hurts the environment. In this work, we try to valorize the nanofiltration and reverse osmosis brine generated from a hybrid desalination unit of treated wastewater located in Tunisia by magnesium recovery and reuse it as a cheap resource for fertilizer production. The brine was first purified by calcium removal. The pH of calcite precipitation was 11.32 and 9.78 using brine NF and brine RO respectively. After that, the filtrate was used to produce brucite. The pH of brucite precipitation was 11.3 and 9.74 for NF and RO brine respectively. 55 % of magnesium was recovered from NF brine and 65.5 % from RO respectively. To obtain a 100 % recovery rate of magnesium for brucite precipitation, the optimal molar alkaline reagent/Mg ratio was 5.5 and the pH was 11.9. The brucite was dissolved in sulfuric acid, then the Epsomite fertilizer was extracted with pure ethanol. The highest weight of epsomite was obtained for a volume ratio of acid/ ethanol of 0.8:3.5. The second fertilizer produced using brine magnesium was struvite. It was obtained for pH 9 and 11 using H2NH4PO4 acid and wastewater as a source of ammonia and phosphate respectively. 90 % and 50 % of magnesium recovery were obtained for the first and the second cases respectively. The infrared spectrum and X-ray diffractogram confirmed the brucite, epsomite, and struvite production using brine magnesium.

Plant and Soil Effects of Alternative Sources of Phosphorous over Three Years of Application

Plant growth and food security depend heavily on phosphorous (P). Recovering and recycling P from animal, municipal, and food waste streams can significantly reduce dependency on traditional mineral P. This is particularly pertinent in the EU regions with limited native P supplies. The agronomic performance of including P-based recycling-derived fertilisers (two struvite and two ashes) or cattle slurry was compared to a conventional mineral P fertilisation programme along with no P and no fertiliser controls over three years. A field-scale experiment was set up to evaluate the perennial ryegrass dry matter yield (DMY), P uptake, and soil test P effects. Struvite, ash, and cattle slurry proved effective in replacing P mineral fertiliser and produced yields similar to those of the mineral fertiliser programme. Differences were observed in plant P recovery, with struvite-based programmes achieving a significantly higher P recovery than ash-based programmes, which had the lowest plant P recovery. Differences in Morgan’s soil test P were also noted, with potato waste struvite (PWS) and poultry litter ash (PLA) showing significantly higher soil test P values. The findings strongly indicate that a range of recycled bio-based fertilisers from the bioeconomy can be used to reduce reliance on conventional imported mineral P fertiliser, with some programmes based on recycled fertilisers even surpassing the performance of conventional linear economy mineral fertilisers.

The Impact of Polyphosphates on the Colloidal Stability of Laponite Particles.

The effect of polyphosphate (polyP) adsorption on the colloidal properties of disc-shaped laponite (LRD) particles was examined in aqueous dispersions with a focus on elucidating the interparticle forces that govern the colloidal stability of the systems. The charge and aggregation rate data of bare LRD exhibited an ionic strength-dependent trend, confirming the presence of double-layer repulsion and van der Waals attraction as major surface interactions. The charge of LRD particles significantly increased in magnitude at elevated polyP concentrations as a result of polyP adsorption and subsequent overcharging of the positively charged sites on the edges of the LRD discs. A transition from stable to unstable LRD colloids was observed with increasing polyP doses indicating the formation of aggregates in the latter systems due to depletion forces and/or bridging interactions induced by dissolved or adsorbed polyP, respectively. The degree of phosphate polymerization influenced neither the charge nor the aggregation mechanism. The findings clearly confirm that polyP adsorption was the driving phenomenon to induce particle aggregation in contrast to other clay types, where phosphate derivatives act as dispersion stabilizing agents. This study provides valuable insights into the early stages of aggregation in colloidal systems involving LRD and polyPs, which have a crucial role in predicting further material properties that are important to designing LRD-polyP composites for applications such as potential phosphate sources in chemical fertilizers.

The cytoplasmic phosphate level has a central regulatory role in the phosphate starvation response of Caulobacter crescentus

In bacteria, the availability of environmental inorganic phosphate is typically sensed by the conserved PhoR-PhoB two-component signal transduction pathway, which uses the flux through the PstSCAB phosphate transporter as a readout of the extracellular phosphate level to control phosphate-responsive genes. While the sensing of environmental phosphate is well-investigated, the regulatory effects of cytoplasmic phosphate are unclear. Here, we disentangle the physiological and transcriptional responses of Caulobacter crescentus to changes in the environmental and cytoplasmic phosphate levels by uncoupling phosphate uptake from the activity of the PstSCAB system, using an additional, heterologously produced phosphate transporter. This approach reveals a two-pronged response of C. crescentus to phosphate limitation, in which PhoR-PhoB signaling mostly facilitates the utilization of alternative phosphate sources, whereas the cytoplasmic phosphate level controls the morphological and physiological adaptation of cells to growth under global phosphate limitation. These findings open the door to a comprehensive understanding of phosphate signaling in bacteria.

Agronomic advantage of bacterial biological nitrogen fixation on wheat plant growth under contrasting nitrogen and phosphorus regimes.

Given their remarkable capacity to convert atmospheric nitrogen into plant-accessible ammonia, nitrogen-fixing microbial species hold promise as a sustainable alternative to chemical nitrogen fertilizers, particularly in economically significant crops like wheat. This study aimed to identify strains with optimal attributes for promoting wheat growth sustainably, with a primary emphasis on reducing reliance on chemical nitrogen fertilizers. We isolated free nitrogen-fixing strains from diverse rhizospheric soils across Morocco. Subsequently, we conducted a rigorous screening process to evaluate their plant growth-promoting traits, including nitrogen fixation, phosphate solubilization, phytohormone production and their ability to enhance wheat plant growth under controlled conditions. Two specific strains, Rhodotorula mucilaginosa NF 516 and Arthrobacter sp. NF 528, were selected for in-depth evaluation, with the focus on their ability to reduce the need for chemical nitrogen supply, particularly when used in conjunction with TSP fertilizer and natural rock phosphate. These two sources of phosphate were chosen to assess their agricultural effectiveness on wheat plants. Twenty-two nitrogen-fixing strains (nif-H+) were isolated from various Moroccan rhizospheric soils, representing Bacillus sp., Pseudomonas sp., Arthrobacter sp., Burkholderia sp. and a yeast-like microorganism. These strains were carefully selected based on their potential to promote plant growth. The findings revealed that the application of Rhodotorula mucilaginosa NF 516 and Arthrobacter sp. NF 528 individually or in combination, significantly improved wheat plant growth and enhanced nutrients (N and P) uptake under reduced nitrogen regimes. Notably, their effectiveness was evident in response to both natural rock phosphate and TSP, demonstrating their important role in wheat production under conditions of low nitrogen and complex phosphorus inputs. This research underscores the significant role of nitrogen-fixing microorganisms, particularly Rhodotorula mucilaginosa NF 516 and Arthrobacter sp. NF 528, in wheat production under conditions of low nitrogen and complex phosphorus inputs. It showcases their potential to reduce chemical nitrogen fertilization requirements by up to 50% without compromising wheat plant yields. Our study emphasizes the importance of bacterial biological nitrogen fixation in meeting the remaining nitrogen requirements beyond this reduction. This underscores the vital role of microbial contributions in providing essential nitrogen for optimal plant growth and highlights the significance of biological nitrogen fixation in sustainable agriculture practices.

Influence of excess sodium and phosphorus on the ionic conductivity of NASICON-structured Na3Zr2(SiO4)2PO4 ceramic solid electrolyte

NASICON-structured Na3Zr2(SiO4)2PO4 (NZSP) is regarded as one of the most promising solid-state electrolytes (SSEs) for all-solid-state Na-ion batteries mainly due to its high thermal stability and wide electrochemical window. However, the existing NZSP tends to exhibit lower ionic conductivity at room temperature. Thus, in order to solve this issue, NaH2PO4 was chosen as a novel phosphate source for the synthesis of NZSP via solid-state reaction method. On top of that, excess sodium (Na) and phosphorus (P) were also added into parent NZSP SSE with different weight percentage ratios to investigate their effects on Na+ ion activation energy. Structural study reveals NZSP with either excess Na or P have the same crystal structure morphology but are dissimilar in terms of the presence of impurities and grain size. NZSP with the excess of Na shows the highest ionic conductivity (1.05 × 10−3 S cm−1) and electrode polarization contributed by the increasing of Na+ carriers and the excess Na+ ion vacancies. These results authenticate that the excess of Na can be an effective way to improve the performance of NZSP SSE for energy storage application.

Structural insights in to the atypical type-I ABC Glucose-6-phosphate importer VCA0625-27 of Vibrio cholerae

Sugar phosphates are potential sources of carbon and phosphate for bacteria. Despite that the process of internalization of Glucose-6-Phosphate (G6P) through plasma membrane remained elusive in several bacteria. VCA0625-27, made of periplasmic ligand binding protein (PLBP) VCA0625, an atypical monomeric permease VCA0626, and a cytosolic ATPase VCA0627, recently emerged as hexose-6-phosphate uptake system of Vibrio cholerae. Here we report high resolution crystal structure of VCA0625 in G6P bound state that largely resembles AfuA of Actinobacillus pleuropneumoniae. MD simulations on VCA0625 in apo and G6P bound states unraveled an ‘open to close’ and swinging bi-lobal motions, which are diminished upon G6P binding. Mutagenesis followed by biochemical assays on VCA0625 underscored that R34 works as gateway to bind G6P. Although VCA0627 binds ATP, it is ATPase deficient in the absence of VCA0625 and VCA0626, which is a signature phenomenon of type-I ABC importer. Further, modeling, docking and systematic sequence analysis allowed us to envisage the existence of similar atypical type-I G6P importer with fused monomeric permease in 27 other gram-negative bacteria.

Biocompatible aggregation-induced emission active polyphosphate-manganese nanosheets with glutamine synthetase-like activity in excitotoxic nerve cells

Glutamine synthetase (GS) is vital in maintaining ammonia and glutamate (Glu) homeostasis in living organisms. However, the natural enzyme relies on adenosine triphosphate (ATP) to activate Glu, resulting in impaired GS function during ATP-deficient neurotoxic events. To date, no reports demonstrate using artificial nanostructures to mimic GS function. In this study, we synthesize aggregation-induced emission active polyP-Mn nanosheets (STPE-PMNSs) based on end-labeled polyphosphate (polyP), exhibiting remarkable GS-like activity independent of ATP presence. Further investigation reveals polyP in STPE-PMNSs serves as phosphate source to activate Glu at low ATP levels. This self-feeding mechanism offers a significant advantage in regulating Glu homeostasis at reduced ATP levels in nerve cells during excitotoxic conditions. STPE-PMNSs can effectively promote the conversion of Glu to glutamine (Gln) in excitatory neurotoxic human neuroblastoma cells (SH-SY5Y) and alleviate Glu-induced neurotoxicity. Additionally, the fluorescence signal of nanosheets enables precise monitoring of the subcellular distribution of STPE-PMNSs. More importantly, the intracellular fluorescence signal is enhanced in a conversion-responsive manner, allowing real-time tracking of reaction progression. This study presents a self-sustaining strategy to address GS functional impairment caused by ATP deficiency in nerve cells during neurotoxic events. Furthermore, it offers a fresh perspective on the potential biological applications of polyP-based nanostructures.

Evaluating the agronomic efficiency of alternative phosphorus sources applied in Brazilian tropical soils

Understanding the efficacy of alternative phosphorus (P) sources in tropical soils is crucial for sustainable farming, addressing resource constraints, mitigating environmental impact, improving crop productivity, and optimizing soil-specific solutions. While the topic holds great importance, current literature falls short in providing thorough, region-specific studies on the effectiveness of alternative P sources in Brazilian tropical soils for maize cultivation. Our aim was to assess the agronomic efficiency of alternative P sources concerning maize crop (Zea mays L.) attributes, including height, shoot dry weight, stem diameter, and nutrient accumulation, across five Brazilian tropical soils. In greenhouse conditions, we carried out a randomized complete block design, investigating two factors (soil type and P sources), evaluating five tropical soils with varying clay contents and three alternative sources of P, as well as a commercial source and a control group. We evaluated maize crop attributes such as height, dry weight biomass, and nutrient accumulation, P availability and agronomic efficiency. Our results showed that, although triple superphosphate (TSP) exhibited greater values than alternative P sources (precipitated phosphorus 1, precipitated phosphorus 2 and reactive phosphate) for maize crop attributes (e.g., height, stem diameter, shoot dry weight and phosphorus, nitrogen, sulfur, calcium and magnesium accumulation). For instance, PP1 source increased nutrient accumulation for phosphorus (P), nitrogen (N), and sulfur (S) by 37.05% and 75.98% (P), 34.39% and 72.07% (N), and 41.94% and 72.69% (S) in comparison to PP2 and RP, respectively. Additionally, PP1 substantially increased P availability in soils with high clay contents 15 days after planting (DAP), showing increases of 61.90%, 99.04%, and 38.09% greater than PP2, RP, and TSP. For Ca and Mg accumulation, the highest values were found in the COxisol2 soil when PP2 was applied, Ca = 44.31% and 69.48%; and Mg = 46.23 and 75.79%, greater than PP1 and RP, respectively. Finally, the highest values for relative agronomic efficiency were observed in COxisol2 when PP1 was applied. The precipitated phosphate sources (PP1 and PP2) exhibited a similar behavior to that of the commercial source (TSP), suggesting their potential use to reduce reliance on TSP fertilization, especially in soils with low clay contents. This study emphasized strategies for soil P management, aimed at assisting farmers in enhancing maize crop productivity while simultaneously addressing the effectiveness of alternative P sources of reduced costs.

Functionalization of PCL-Based Fiber Scaffolds with Different Sources of Calcium and Phosphate and Odontogenic Potential on Human Dental Pulp Cells.

This study investigated the incorporation of sources of calcium, phosphate, or both into electrospun scaffolds and evaluated their bioactivity on human dental pulp cells (HDPCs). Additionally, scaffolds incorporated with calcium hydroxide (CH) were characterized for degradation, calcium release, and odontogenic differentiation by HDPCs. Polycaprolactone (PCL) was electrospun with or without 0.5% w/v of calcium hydroxide (PCL + CH), nano-hydroxyapatite (PCL + nHA), or β-glycerophosphate (PCL + βGP). SEM/EDS analysis confirmed fibrillar morphology and particle incorporation. HDPCs were cultured on the scaffolds to assess cell viability, adhesion, spreading, and mineralized matrix formation. PCL + CH was also evaluated for gene expression of odontogenic markers (RT-qPCR). Data were submitted to ANOVA and Student's t-test (α = 5%). Added CH increased fiber diameter and interfibrillar spacing, whereas βGP decreased both. PCL + CH and PCL + nHA improved HDPC viability, adhesion, and proliferation. Mineralization was increased eightfold with PCL + CH. Scaffolds containing CH gradually degraded over six months, with calcium release within the first 140 days. CH incorporation upregulated DSPP and DMP1 expression after 7 and 14 days. In conclusion, CH- and nHA-laden PCL fiber scaffolds were cytocompatible and promoted HDPC adhesion, proliferation, and mineralized matrix deposition. PCL + CH scaffolds exhibit a slow degradation profile, providing sustained calcium release and stimulating HDPCs to upregulate odontogenesis marker genes.