Phosphate Concentration Research Articles

Investigation on improvement of enantioseparation based on clindamycin phosphate by chiral deep eutectic solvents in capillary electrophoresis.

In this work, the potential synergetic effect between deep eutectic solvents and an antibiotic chiral selector (clindamycin phosphate) for enantioseparation was investigated in capillary electrophoresis. We synthesized a series of deep eutectic solvents with choline chloride as hydrogen bond acceptor and three α-hydroxyl acids (l-lactic acid, l-malic acid, and l-tartaric acid) as hydrogen bond donors. Compared to the single clindamycin phosphate separation system, significantly improved separations of model drugs were observed in several synergetic systems. Compared to deep eutectic solvents with a single hydrogen bond donor, deep eutectic solvents with mixed-type hydrogen bond donors were superior. The influences of several key parameters including the type and proportion of organic modifier, clindamycin phosphate concentrations, deep eutectic solvents concentrations, and buffer pH were investigated in detail. The mechanism of the enhanced separations in deep eutectic solvents systems was investigated by means of electroosmotic flow analysis, nuclear magnetic resonance analysis, and molecular modeling. It was the first time that the synergetic systems between deep eutectic solvents and antibiotic chiral selector were established in capillary electrophoresis, and these deep eutectic solvents were demonstrated to have a good synergetic effect with clindamycin phosphate for enantioseparation.

Preparation of an activated adsorbent from water treatment plant sludge for phosphate removal from wastewater: optimization, characterization, isotherm, and kinetics studies

Abstract Purifying water for diverse uses is vital, but concerns lie with the sustainability and accessibility of purification materials. As such, this study converted readily available water treatment plant sludge (WTPS) into activated adsorbent for phosphate removal in wastewater. WTPS was activated via thermal activation at 300 °C temperature and chemical activation processes of 3 M acid concentration, 4 h activation time, and 75 °C activation temperature, and then characterized using Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), Fourier transform infrared, elemental analyzer, and differential scanning calorimetry. SEM and BET analyses revealed a highly porous adsorbent (279.2 m2/g) for efficient adsorption. On top of the activation process, preliminary experiments and numerical optimization using response surface methodology (RSM) were designed and conducted. Through optimizing conditions, it was found that 70 min of contact time, pH 3, 3 g/L adsorbent dose, and 30 mg/L initial phosphate concentration as optimal, yielding 83% removal efficiency. Furthermore, adsorption kinetics and isotherm models were examined and the second-order kinetics and Langmuir isotherm models indicated best fit. Notably, the activated sludge could be regenerated for three cycles before efficiency dropped below 70%. Thus, activated WTPS presents a promising, sustainable, and readily available adsorbent for phosphate removal in wastewater treatment.

Citizen scientists filling knowledge gaps of phosphate pollution dynamics in rural areas

In situ monitoring is fundamental to manage eutrophication in rivers and streams. However, in recent decades, the frequency and spatial coverage of regulatory monitoring have often been reduced due to funding and infrastructure limitations. This reduction has made it impossible to provide adequate coverage for most water bodies. In this study, trained citizen scientists filled spatial and temporal gaps in agency monitoring across a major catchment in rural England. By integrating data from citizen scientists, regulatory agencies, and the local water company, it was possible to demonstrate the opportunities for hypothesis-based citizen scientist monitoring to identify continuous and event-driven sources of phosphate pollution. Local citizen scientists effectively covered important spatial gaps, investigating river conditions both upstream and downstream of suspected pollution point sources, improving the identification of their temporal dynamics. When combined with long-term monitoring data from regulatory agencies, it became possible to identify areas within the catchment that exhibited increased phosphate concentrations during periods of low river discharge (summer). Inter-annual trends and anomaly detection suggested that continuous pollution sources dominated over event-driven sources in many sub-basins, allowing for the prioritisation of mitigation actions. This study highlights the opportunity for citizen scientists to fill gaps in regulatory monitoring efforts and contribute to the improved management of eutrophication in rural catchments.

Exploring virus-host-environment interactions in a chemotrophic-based underground estuary

BackgroundViruses play important roles in modulating microbial communities and influencing global biogeochemistry. There is now growing interest in characterising their ecological roles across diverse biomes. However, little is known about viral ecology in low-nutrient, chemotrophic-based environments. In such ecosystems, virus-driven manipulation of nutrient cycles might have profound impacts across trophic levels. In particular, anchialine environments, which are low-energy underground estuaries sustained by chemotrophic processes, represent ideal model systems to study novel virus-host-environment interactions.ResultsHere, we employ metagenomic sequencing to investigate the viral community in Bundera Sinkhole, an anchialine ecosystem rich in endemic species supported by microbial chemosynthesis. We find that the viruses are highly novel, with less than 2% representing described viruses, and are hugely abundant, making up as much as 12% of microbial intracellular DNA. These highly abundant viruses largely infect important prokaryotic taxa that drive key metabolic processes in the sinkhole. Further, the abundance of viral auxiliary metabolic genes (AMGs) involved in nucleotide and protein synthesis was strongly correlated with declines in environmental phosphate and sulphate concentrations. These AMGs encoded key enzymes needed to produce sulphur-containing amino acids, and phosphorus metabolic enzymes involved in purine and pyrimidine nucleotide synthesis. We hypothesise that this correlation is either due to selection of these AMGs under low phosphate and sulphate concentrations, highlighting the dynamic interactions between viruses, their hosts, and the environment; or, that these AMGs are driving increased viral nucleotide and protein synthesis via manipulation of host phosphorus and sulphur metabolism, consequently driving nutrient depletion in the surrounding water.ConclusionThis study represents the first metagenomic investigation of viruses in anchialine ecosystems, and provides new hypotheses and insights into virus-host-environment interactions in such ‘dark’, low-energy environments. This is particularly important since anchialine ecosystems are characterised by diverse endemic species, both in their microbial and faunal assemblages, which are primarily supported by microbial chemosynthesis. Thus, virus-host-environment interactions could have profound effects cascading through all trophic levels.

Engineering Dual-Responsive Prodrug-MOFs as Immunogenic Cell Death Initiator for Enhancing Cancer Immunotherapy.

In recent years, the anticancer effects of disulfiram, a clinical drug for anti-alcoholism, are confirmed. However, several defects limit the clinical translation of disulfiram obviously, such as Cu(II)-dependent anticancer activity, instability, and non-selectivity for cancer cells. Herein, a phosphate and hydrogen peroxide dual-responsive nanoplatform (PCu-HA-DQ) is reported, which is constructed by encapsulating disulfiram prodrug (DQ) and modifying hyaluronic acid (HA) on copper doping metal-organic frameworks (PCu MOFs). PCu-HA-DQ is expected to accumulate in tumor by targeting CD-44 receptors and enable guidance with magnetic resonance imaging. Inside the tumor, Cu(DTC)2 will be generated in situ based on a dual-responsive reaction. In detail, the high concentration of phosphate can induce the release of DQ, after that, the intracellular hydrogen peroxide will further mediate the generation of Cu(DTC)2 . In vitro and in vivo results indicate PCu-HA-DQ can induce the apoptosis as well as immunogenic cell death (ICD) of tumor cells distinctly, leading to enhanced immune checkpoint inhibitor (ICI) efficacy by combining the anti-programmed death-1 antibody. This work provides a portable strategy to construct a dual-responsive nanoplatform integrating tumor-targeted ability and multi-therapy, and the designed nanoplatform is also an ICD inducer, which presents a prospect for boosting systemic antitumor immunity and ICI efficacy.

Cyclic Voltammetry Method for Analysis of Phosphate Concentration in Water

Phosphate is a nontoxic element but a limiting element for productivity. Several methods have been established to analyze the phosphate concentration in water. This study aims to analyze phosphate concentration in water using the voltammetry method using cyclic voltammetry. Cyclic voltammetry is an electroanalytical method that measures the current outcome of oxidation-reduction reactions in response to the potential. The current outcome is directly proportional to the phosphate concentration in the solution. The calibration curve was formed from the KH2PO4 standard solution using concentrations of 0.1 mg/L, 0.2 mg/L, 0.4 mg/L, 0.8 mg/L, and 1.6 mg/L. The voltammogram showed that the analyte does not have an anode peak current (Ipa), which means that the analyte solution did not have an oxidation reaction, so the cathode peak current (Ipc) value was used. Based on the calibration curve, the linear regression graph with a straight-line equation is y = -0,00000645632x - 0,000208737 with R2 of 0,99737. Meanwhile, this cyclic voltammetry method was validated by calculating the LOD and LOQ values; the results are 0.1034 mg/L and 0.3134 mg/L, respectively. Hence, based on the analysis of phosphate concentration in water samples, this method works satisfactorily and is suitable for routine analysis because of its advantages.

Mariculture may intensify eutrophication but lower N/P ratios: a case study based on nutrients and dual nitrate isotope measurements in Sansha Bay, southeastern China

The mariculture industry has grown rapidly worldwide over the past few decades. The industry helps meet growing food demands and may provide an effective means of carbon sequestration; however, it may harm the marine ecological environment, and the extent of its impact depends on the type of mariculture. Here we focus on the impact of mariculture on the nutrient status and eutrophication in Sansha Bay, which is a typical aquaculture harbor in southeastern China that employs a combination of shellfish and seaweed farming. Nutrient concentrations and dual nitrate isotopes were measured in Sansha Bay during the winter of 2021. The average concentrations of nitrate and phosphate were 31.3 ± 10.5 and 2.26 ± 0.84 µM, respectively, indicating that the water was in a eutrophic state. However, the N/P ratios were relatively low (14.3 ± 2.2). Nitrate isotope measurements were 8.8‰–11.9‰ for δ15N-NO3− and 2.2‰–6.0‰ for δ18O-NO3−. Source analysis based on the nitrate isotope measurements indicates that nitrate in Sansha Bay is derived mainly from the excretion of organisms and sewage discharge from mariculture. The isotopic fractionation model of nitrate assimilation by organisms indicates that surface waters in Sansha Bay experience strong biological uptake of nitrate, which is likely related to seaweed farming in winter. The low N/P ratios may be attributed to excessive nitrogen uptake (relative to phosphorus) during shellfish and seaweed farming, as well as nitrogen removal through sediment denitrification, which is fueled by the sinking of particulate organic matter from mariculture. Overall, our study shows that mariculture activities dominated by shellfish and seaweed cultivation in Sansha Bay may exacerbate eutrophication but reduce N/P ratios in the water column in aquaculture areas.

Continuous Renal Replacement Therapy During Long-term Normothermic Machine Perfusion of Human Donor Livers for up to 7 D.

Normothermic machine perfusion (NMP) is used to preserve and test donor livers before transplantation. During NMP, the liver is metabolically active and produces waste products, which are released into the perfusate. In this study, we describe our simplified and inexpensive setup that integrates continuous renal replacement therapy (CRRT) with NMP for up to 7 d. We also investigated if the ultrafiltrate could be used for monitoring perfusate concentrations of small molecules such as glucose and lactate. Perfusate composition (urea, osmolarity, sodium, potassium, chloride, calcium, magnesium, phosphate, glucose, and lactate) was analyzed from 56 human NMP procedures without CRRT. Next, in 6 discarded human donor livers, CRRT was performed during NMP by integrating a small dialysis filter (0.2 m2) into the circuit to achieve continuous ultrafiltration combined with continuous fluid substitution for up to 7 d. Within a few hours of NMP without CRRT, a linear increase in osmolarity and concentrations of urea and phosphate to supraphysiological levels was observed. After integration of CRRT into the NMP circuit, the composition of the perfusate was corrected to physiological values within 12 h, and this homeostasis was maintained during NMP for up to 7 d. Glucose and lactate levels, as measured in the CRRT ultrafiltrate, were strongly correlated with perfusate levels (r = 0.997, P < 0.001 and r = 0.999, P < 0.001, respectively). The integration of CRRT into the NMP system corrected the composition of the perfusate to near-physiological values, which could be maintained for up to 7 d. The ultrafiltrate can serve as an alternative to the perfusate to monitor concentrations of small molecules without potentially compromising sterility.

Temporal patterns of bacterial communities in the Billings Reservoir system

In this study, high-throughput sequencing of 16S rRNA amplicons and predictive PICRUSt functional profiles were used to perform a comprehensive analysis of the temporal bacterial distribution and metabolic functions of 19 bimonthly samples collected from July 2019 to January 2020 in the surface water of Billings Reservoir, São Paulo. The results revealed that most of the bacterial 16S rRNA gene sequences belonged to Cyanobacteria and Proteobacteria, which accounted for more than 58% of the total bacterial abundance. Species richness and evenness indices were highest in surface water from summer samples (January 2020), followed by winter (July 2019) and spring samples (September and November 2019). Results also showed that the highest concentrations of sulfate (SO4–2), phosphate (P), ammonia (NH3), and nitrate (NO3-) were detected in November 2019 and January 2020 compared with samples collected in July and September 2019 (P < 0.05). Principal component analysis suggests that physicochemical factors such as pH, DO, temperature, and NH3 are the most important environmental factors influencing spatial and temporal variations in the community structure of bacterioplankton. At the genus level, 18.3% and 9.9% of OTUs in the July and September 2019 samples, respectively, were assigned to Planktothrix, while 14.4% and 20% of OTUs in the November 2019 and January 2020 samples, respectively, were assigned to Microcystis. In addition, PICRUSt metabolic analysis revealed increasing enrichment of genes in surface water associated with multiple metabolic processes rather than a single regulatory mechanism. This is the first study to examine the temporal dynamics of bacterioplankton and its function in Billings Reservoir during the winter, spring, and summer seasons. The study provides comprehensive reference information on the effects of an artificial habitat on the bacterioplankton community that can be used to interpret the results of studies to evaluate and set appropriate treatment targets.

Effect of acidification or fermentation of barley grain using Limosilactobacillus reuteri or Weissella cibaria on inositol phosphate hydrolysis in vitro

Fermentation of cereal grains may hydrolyse myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) and increase concentration of lower order inositol phosphates (InsP) in vitro, thereby increasing nutrient digestibility in diets of swine and poultry. Effects of chemical acidification or fermentation with the lactic acid-producing bacteria Limosilactobacillus reuteri or Weisella cibaria of high β-glucan hull-less barley grain on pH, organic acid concentration, InsP6 hydrolysis and lower order InsP formation were assessed in vitro. In 3 batches, ground barley grain was treated in four forms balanced for water content: 1) unfermented barley (Control); 2) chemically acidified barley with lactic acid and acetic acid (0.019 L/kg barley grain at a ratio of 4:1 (volume/volume)) (ACD); 3) barley fermented with L. reuteri TMW 1.656 (Fermented with L. reuteri); and 4) barley fermented with W. cibaria 10 M FUA3120 (Fermented with W. cibaria). For 24 h in an incubator, ACD and Fermented with L. reuteri were incubated at 37 °C and Fermented with W. cibaria at 30 °C. Barley inositol phosphate6-phosphorus (InsP6-P) was 68%, 64% and 41% lower, respectively, for ACD, Fermented with L. reuteri or Fermented with W. cibaria than Control. Barley grain pH after 24 h, concentration of InsP6-P, inositol phosphate5-phosphorus (InsP5-P), inositol phosphate4-phosphorus (InsP4-P) and sum inositol phosphate6–2-phosphorus (InsP6–2-P) were lower (P < 0.05) for ACD and Fermented barley grain than Control and Fermented with L. reuteri than W. cibaria. Acetate, lactate, inositol phosphate3-phosphorus (InsP3-P) and inositol phosphate2-phosphorus (InsP2-P) concentration was greater (P < 0.05) for ACD and Fermented barley grain than Control. Lactate and InsP2-P concentration were greater (P < 0.01) for Fermented with L. reuteri than W. cibaria. Total P release, cumulative P release of InsP6-P, InsP5-P, InsP4-P and InsP3-P were greater (P < 0.01) for Fermented with L. reuteri than W. cibaria. In conclusion, lower pH in ACD and Fermentation indicated that acidification is important for InsP6 hydrolysis via intrinsic phytase activation in barley grain in vitro. Between strains, fermentation with L. reuteri maximised acidification, lactate concentration and degradation of InsP6-P, InsP5-P, InsP4-P in barley grain.

Advanced thermodynamic approach to adsorption of charged adsorbates from aqueous electrolyte solutions

This study present estimation of the thermodynamic parameters and the influence of ionic activity coefficient on the thermodynamic equilibrium constant of adsorption of phosphates on fly ash. The adsorption was conducted over a wide range of initial phosphate concentrations at different pH values pH = (3; 7; 10). The adsorption results were treated using the Langmuir, Freundlich and Sips adsorption isotherms, which provide information about the maximum adsorption capacity. The Langmuir and Sips isotherms were a satisfactory fit to the adsorption data, especially at pH = 3, with an acceptable regression coefficient over the entire concentration range, Langmuir (r2 = 0.9737) and Sips (r2 = 0.9969). The estimated maximum phosphate sorption capacity of fly ash was 6.21 ± 0.68 (mmol·g−1) according to Langmuir and 4.19 ± 0.16 (mmol·g−1) according to the Sips model, at pH = 3.0. However, there is no data in the published literature for estimating the thermodynamic parameters of the phosphate adsorption process using thermodynamic models for activity coefficients. Novel approach of this paper was determination of the thermodynamic equilibrium constant and Gibbs free energy, using the Pitzer ion-interaction model to predict the nature of adsorption. The Pitzer-ion interaction model was used for the mixed ionic systems, taking into consideration the effect of other present ions besides phosphates in the equilibrium solution resulting from fly ash desorption. The procedure for comprehensive estimation of the ion activity coefficient at maximum adsorption capacity and the dimensionless thermodynamic equilibrium constant using Langmuir's and Sips’s constants was presented. The calculated value of the phosphate activity coefficient in the equilibrium solution was γH2PO4,e = 0.7003 ± 0.0027 and the converted molar activity coefficient was γH2PO4,e = 0.6903 ± 0.0027. The estimated values of Gibbs free energy were: ΔGL = −6.788 ± 0.521 kJ·mol−1 based on Langmuir equilibrium constant and ΔGa = −7.707 ± 0.527 kJ·mol−1 based on activity and thermodynamic equilibrium constant. According to Sips model, the adsorption process is even more spontaneous, with the Gibbs free energy calculated using the phosphate activity coefficient and the thermodynamic equilibrium constant, ΔGa = −9.707 ± 0.617 kJ·mol−1. Consideration of the ionic activity coefficient is particularly important for large, charged adsorbates at higher concentrations, as the absolute difference in free energy for adsorption is app. 12 %. The scientific contribution is reflected in obtaining the necessary and more accurate information for the improvement of adsorption processes and possibly for the upgrading of fly ash in overall wastewater treatment technology.

Determination of phosphate in food based on molybdenum yellow derivatization coupled with resonance Rayleigh scattering method.

This paper proposed a rapid, selective and sensitive molybdenum yellow derivatization coupled with Resonance Rayleigh scattering (MYD-RRS) method for detection of phosphate. Under the acidic condition, phosphate can be selectively transformed to Keggin type of phosphomolybdic acid (PMA, i.e., PMo12O403-) through molybdenum yellow derivatization reaction prior to RRS detection. The PMA can further react with cationic methyl violet (MV) to form larger PMA-MV ion association complexes, generating significant RRS signal. The concentration of phosphate was linearly related to the RRS signal in the range of 8-200ng/mL, with the determining coefficient (R2) of 0.9973 and the detection limit of 4ng/mL. The analytical procedure can be completed within 10min and the RRS signal intensity can remain stable more than 4h. The method showed good stability toward temperature and time, and good anti-interference capability. The method was applied to the determination of phosphate in real food samples with the recovery of 85-117% and RSD of 1-5.2%. With the advantages of rapidness, high sensitivity and good selectivity, the MYD-RRS method exhibits great potential to the determination of phosphate in food. It also provides an instructive strategy for detection of analytes with weak RRS signal.

Zinc Deficiency Promotes Calcification in Vascular Smooth Muscle Cells Independent of Alkaline Phosphatase Action and Partly Impacted by Pit1 Upregulation.

Inorganic phosphate (Pi) is a critical determinant of calcification, and its concentration is regulated by alkaline phosphatase (ALP) and Pit1. ALP is a key regulator of osteogenic calcification and acts by modulating local inorganic phosphate (Pi) concentrations through hydrolyzing pyrophosphate in the extracellular matrix (ECM). Pit1, a sodium-dependent phosphate transporter, regulates calcification via facilitating phosphate uptake within the cells. To investigate whether zinc differentially regulates osteoblastic and vascular calcifications, we examined ALP activity and Pit1 in osteoblastic and vascular smooth muscle cells (VSMCs). Our findings demonstrate that calcification in osteoblastic MC3T3-E1 cells is decreased via diminished ALP action under zinc deficiency. In contrast, zinc-deficiency-induced calcification in VSMCs is independent of ALP action, as demonstrated by very weak ALP activity and expression in calcified VSMCs. In zinc-deficient A7r5 VSMC, P accumulation increased with increasing Na phosphate concentration (3-7 mM) but not with β-GP treatment, which requires ALP activity to generate Pi. Ca deposition also increased with Na phosphate in a dose-dependent manner; in contrast, β-GP did not affect Ca deposition. In osteoblastic cells, Pit1 expression was not affected by zinc treatments. In contrast, Pit1 expression is highly upregulated in A7r5 VSMC under zinc deficiency. Using phosphonoformic acid, a competitive inhibitor of Pit1, we showed that calcification is inhibited in both A7r5 and MC3T3-E1 cells, indicating a requirement for Pit1 in both calcifications. Moreover, the downregulation of VSMC markers under zinc deficiency was restored by blocking Pit1. Taken together, our results imply that zinc-deficiency-induced calcification in VSMC is independent of ALP action in contrast to osteoblastic calcification. Moreover, Pit1 expression in VSMCs is a target for zinc deficiency and may mediate the inhibition of VSMC marker expression under zinc deficiency.

The threat of groundwater pollution for petrifying springs; defining nutrient threshold values for an endangered bryophyte dominated habitat

Eutrophication by human activities is increasingly affecting ecosystem functioning and plant community composition. So far, studies mainly focus on the effects of atmospheric nitrogen deposition, surface water eutrophication or soil nutrient accumulation. Groundwater pollution of spring habitats, however, has received much less attention, although numerous papers report groundwater nutrient enrichment worldwide. This study presents a survey on groundwater pollution (with emphasis on nitrate and phosphate) and bryophyte composition in 51 ambient petrifying springs in 5 NW European countries, which were compared to published data from 173 other sites in 11 European countries.The reviewed dataset covers a broad range of unpolluted to heavily polluted springs with nitrate concentrations between 0.7 and 3227 μmol l−1. Most petrifying springs in the rural lowlands of NW Europe were found to have elevated concentrations of nitrate and phosphate with the most polluted springs occurring in The Netherlands.The cover of individual characteristic bryophyte species significantly correlates with groundwater nutrient concentrations indicating that nutrient pollution of spring waters affects bryophyte composition. Palustriella commutata, Eucladium verticillatum and Brachythecium rivulare prefer unpolluted petrifying springs whereas Cratoneuron filicinum and Pellia endiviifolia show a much broader tolerance to groundwater pollution. In order to sustain at least the basic conditions for the typical bryophyte composition of petrifying springs habitats, threshold values of 288 μmol (18 mg l−1) NO3− l−1 and 0.42 μmol (0.04 mg l−1) ortho-PO43- l−1 were defined.Data analysis of the spring water composition indicates that the main source for nutrient and nutrient induced base cation enrichment are nitrate losses from intensively used agricultural fields. The anthropogenically induced but regionally different chemical processes in subsoil and aquifers can result in different levels of nutrient pollution in springs.Further regulations for nitrate and phosphate application are required to conserve and restore groundwater fed ecosystems in Europe.

Exploration of the nitrification process in surface sediment of a hypereutrophic intertidal zone via hydroxylamine monitoring

Hydroxylamine is considered an indicator of nitrification, as it is both produced and consumed during the ammonium (NH4+) oxidation process. In this study, to explore the site of active nitrification and elucidate the factors controlling nitrification, hydroxylamine concentrations in the seawater and porewater of the hypereutrophic Yatsu tidal flat, eastern Japan, were measured using the iodine oxidation method with a Sep-Pak C18 cartridge. The concentrations over approximately 2 years indicated that nitrification was more active in the surface sediment than in seawater. This would support denitrification in the surface sediment via active nitrification–denitrification, which removes N. In addition, multiple linear regression analysis indicated that the concentration in porewater was positively correlated with the seawater parameters of nitrate (NO3−) concentration, NH4+ concentration, and temperature, while among porewater parameters, it was negatively correlated with the phosphate (PO43−) concentration and positively correlated with the NH4+ concentration. These relationships between hydroxylamine concentration and environmental factors suggest that porewater nitrification increases with higher temperature and NH4+ supply from seawater and porewater, as well as under oxic conditions. Our results demonstrate that hydroxylamine is a useful indicator of sediment nitrification in the hypereutrophic intertidal zone.

P-17 Hypophosphatemia related to intravenous iron therapy: A case report

Abstract Introduction Intravenous iron supplementation is a good alternative to oral iron replacement in iron deficiency anaemia. Intravenous iron formulations such as ferric carboxymaltose allow administration of high doses of elemental iron and enable correction of total iron deficit in one or two infusions. An important complication of ferric carboxymaltose is hypophosphatemia caused by increased secretion of the phosphaturic hormone, fibroblast growth factor 23 (FGF23). In this case, we aimed to present our patient with this rare side effect of intravenous iron replacement. Clinical Case A 40-year-old female patient who has no chronic systemic disease was admitted to our endocrinology service for fatigue and weakness. In the patient's history, it was learned that she had been treated with 2500 mg intravenous iron replacement (ferric carboxymaltose) for iron deficiency anaemia in the last month. In the laboratory tests; serum phosphorus 1.05 mg/dl (normal 2.5-4.5 mg/dl), corrected calcium 8.45 mg/dl (normal 8.4-10.2 mg/dl), 25-OH vitamin D 31.4 µg/L (normal &amp;gt;30 µg/L), parathormone 83.2 pg/ml (normal 15-65 ng/ml), alkaline phosphatase 63 U/L (normal 35-105 U/L). Fractional excretion of phosphate (FePO4) confirmed renal phosphate wasting (FePO4: 28.6%; normal &amp;lt;5%). Urinary protein and glucose were negative. FGF23 measured 71 pg/ml (normal &amp;lt;59 pg/mL). Intravenous iron-induced hypophosphataemia was suspected. After initiation of oral phosphate and 1,25-dihydroxyvitamin D3 supplementation, serum phosphate rose to reference range (Figure 1). The patient was taken to outpatient follow-up. Conclusion Physicians should be aware of hypophosphatemia as a common complication of intravenous iron therapy and monitor serum phosphate concentrations in patients receiving repeated doses.Figure 1.Patient phosphorus data during follow-up

Integration of rice apocarotenoid profile and expression pattern of Carotenoid Cleavage Dioxygenases reveals a positive effect of β-ionone on mycorrhization

Carotenoids are susceptible to degrading processes initiated by oxidative cleavage reactions mediated by Carotenoid Cleavage Dioxygenases that break their backbone, leading to products called apocarotenoids. These carotenoid-derived metabolites include the phytohormones abscisic acid and strigolactones, and different signaling molecules and growth regulators, which are utilized by plants to coordinate many aspects of their life. Several apocarotenoids have been recruited for the communication between plants and arbuscular mycorrhizal (AM) fungi and as regulators of the establishment of AM symbiosis. However, our knowledge on their biosynthetic pathways and the regulation of their pattern during AM symbiosis is still limited. In this study, we generated a qualitative and quantitative profile of apocarotenoids in roots and shoots of rice plants exposed to high/low phosphate concentrations, and upon AM symbiosis in a time course experiment covering different stages of growth and AM development. To get deeper insights in the biology of apocarotenoids during this plant-fungal symbiosis, we complemented the metabolic profiles by determining the expression pattern of CCD genes, taking advantage of chemometric tools. This analysis revealed the specific profiles of CCD genes and apocarotenoids across different stages of AM symbiosis and phosphate supply conditions, identifying novel reliable markers at both local and systemic levels and indicating a promoting role of β-ionone in AM symbiosis establishment.

Outwelling of reduced porewater drives the biogeochemistry of dissolved organic matter and trace metals in a major mangrove‐fringed estuary in Amazonia

AbstractMangrove‐fringed estuaries are intertidal ecosystems discharging significant amounts of dissolved organic matter (DOM) into coastal oceans. DOM in these ecosystems is derived from autochthonous production, fluvial input, and mangrove porewater outwelling; however, differentiating between these sources remains challenging. Our incomplete understanding of the biogeochemical factors controlling DOM dynamics and its relationship with nutrient and trace metal cycling still hinders the formulation of elemental budgets in coastal environments. Here, we relate the DOM composition in a mangrove‐fringed estuary in North Brazil (Amazonia) to the redox conditions at the formation sites. We combined molecular DOM analyses via ultrahigh‐resolution mass spectrometry (FT‐ICR‐MS) with parallel factor analysis of excitation–emission fluorescence matrices (EEM‐PARAFAC), nutrient and redox‐sensitive trace metal analyses. During low tide, the influx of oxygen‐depleted porewater carried terrigenous DOM, inorganic nutrients, and trace metals into the mangrove‐fringed creeks. Precipitation of metal(hydr)oxides and microbial turnover controlled nutrient and trace metal dynamics in the estuary. The highest inorganic nitrogen concentrations within the upper mangrove‐fringed estuary indicated outwelling from mangrove sediments as an essential source. Phosphate concentrations were highest within the lower mangrove‐fringed estuary, where available phosphate likely exceeded precipitation with iron(hydr)oxides. We tracked the DOM transport to the coastal ocean using a novel molecular index derived from sulfidic porewater (ISuP). Outwelling of recalcitrant DOM from mangrove habitats is relevant in the context of blue carbon storage. Therefore, applying our molecular proxy (ISuP), together with trace‐metal and optical DOM analyses, is a powerful approach for differentiating contributions of diverse DOM sources in highly complex coastal ecosystems.

Acidification is required for calcium and magnesium concentration measurements in equine urine

BackgroundAcidification of equine urine to promote dissociation of ion complexes is a common practice for urine ion concentration measurements. The objective of this study was to evaluate the effect of acidification and storage after acidification on calcium (Ca), magnesium (Mg) and phosphate (P) concentrations and on fractional excretion (FE) of these electrolytes. Thirty-two fresh equine urine samples were analysed between December 2016 and July 2020. Complete urinalysis (stick and sediment) was performed on all samples. Ca, Mg, P and creatinine concentrations were measured in supernatant of centrifuged native urine, urine directly centrifuged after acidification and urine centrifuged 1 hour after acidification. Urine was acidified with hydrochloric acid to reach a pH of 1–2. Ca, Mg, P and creatinine concentrations were also measured in blood plasma, and fractional excretion of each electrolyte was calculated. Equality of medians was tested with Friedman tests and Bland-Altman bias plots were used to show the agreement between conditions.ResultsAcidification had a statistically significant effect on Ca and Mg concentrations, FECa and FEMg. Bland-Altman plot revealed a strong positive proportional bias between Ca concentration in native and acidified urine with a mean bias of 17.6 mmol/l. For Mg concentration, the difference between native and acidified urine was small with a mean bias of 1.8 mmol/l. The increase in FECa was clinically relevant. Storage of acidified urine had no effect on any of the measured ion concentrations. All P concentrations in native urine samples were below the detection limit of the assay and statistical analysis and calculation of FEP was not possible.ConclusionsUrine acidification is essential for accurate measurement of Ca and Mg concentrations and therefore FE calculations in equine urine. Storage time of 1 hour after acidification does not significantly change Ca and Mg concentrations.

Magnesium or bentonite modified almond kernel biochar for phosphate adsorption from contaminated water solutions

The potential of almond kernel, physically activated by nitrogen/steam, or chemically activated by Mg2+ or bentonite and then by nitrogen/steam, to adsorb phosphate from wastewaters was evaluated. The performance of biochar was studied as a function of initial phosphate concentration, adsorbent dose, contact time and solution pH. The mechanism of adsorption was investigated by carrying out structural, chemical and mineralogical analyses of the material before and after phosphate adsorption, as well as by applying two isotherm models, simulating the experimental data. The results showed that the specific surface area increased about 260 times after activation. Adsorption of phosphate was fast within 30 min, while reached equilibrium after 12 h. For Mg2+ modified material a higher ionic strength facilitated the uptake of phosphate by the biochar up to 59%, in contrast to the bentonite modified material, where adsorption of phosphate was complete (100%) at an initial concentration of 50 mg/L, declining thereafter. Mg2+ modified material was best fitted by the Freundlich model, while bentonite modified material was best fitted by the Langmuir model. For an adsorbent dose of 2 g/L maximum phosphate adsorption capacity after Mg2+ or bentonite modification was 82 mg/g and 54 mg/g, respectively. In the case of Mg2+ modification the potential mechanisms of adsorption were surface precipitation, electrostatic attraction, chemical complexation or electron coordination between the phosphate ion and the adsorbent. For bentonite modification, chemical complexation and π-π electron coordination were the potential adsorption mechanisms.