Water-soluble Phosphate Research Articles

Interaction with IP6K1 supports pyrophosphorylation of substrate proteins by the inositol pyrophosphate 5-InsP7.

Inositol pyrophosphates (PP-InsPs) are a sub-family of water soluble inositol phosphates that possess one or more diphosphate groups. PP-InsPs can transfer their β-phosphate group to a phosphorylated Ser residue to generate pyrophosphorylated Ser. This unique post-translational modification occurs on Ser residues that lie in acidic stretches within an intrinsically disordered protein sequence. Serine pyrophosphorylation is dependent on the presence of Mg2+ ions, but does not require an enzyme for catalysis. The mechanisms by which cells regulate PP-InsP-mediated pyrophosphorylation are still unknown. We performed mass spectrometry to identify interactors of IP6K1, an enzyme responsible for the synthesis of the PP-InsP 5-InsP7. Interestingly, IP6K1 interacted with several proteins that are known to undergo 5-InsP7-mediated pyrophosphorylation, including the nucleolar proteins NOLC1, TCOF and UBF1, and AP3B1, the β subunit of the AP3 adaptor protein complex. The IP6K1 interactome also included CK2, a protein kinase that phosphorylates Ser residues prior to pyrophosphorylation. We observe the formation of a protein complex between IP6K1, AP3B1, and the catalytic α-subunit of CK2, and show that disrupting IP6K1 binding to AP3B1 lowers its in vivo pyrophosphorylation. We propose that assembly of a substrate-CK2-IP6K complex would allow for coordinated pre-phosphorylation and pyrophosphorylation of the target serine residue, and provide a mechanism to regulate this enzyme-independent modification.

Mapping of Water and Soil Quality Parameters in the Gampaha-Ihalagama East and Eldeniya East Grama Niladhari Divisions, Sri Lanka

Water and soil are important natural resources, and the study of their distribution is of great interest. The Grama Niladhari Divisions, Ihalagama-East and Eldeniya-East, located in the Gampaha district, are selected as the study areas, and this is done as a pilot study. Different water and soil quality parameters are investigated followed by the construction of contour maps. As water quality parameters, pH, conductivity, phosphate content, nitrate content, and Ca2+ hardness were determined, and as soil quality parameters, pH, nitrate, organic matter, water-soluble Na+ and K+, extractable Na+ and K+, and water-soluble Ca2+ ion contents were determined. The pH of water samples lies within the range of 4.41 - 7.11 and 3.79 – 7.18 in the Ihalagama-East and Eldeniya East divisions, respectively. Almost all the samples have acidic pH values, with some falling below the lower limit of the WHO guidelines for safe drinking water (6.5 - 8.5). Conductivity values vary from 52.0 - 277.0 µS/cm and between 54.0 – 403.0 µS/cm, respectively, which is below the WHO permissible level of 1500 µS/cm. The phosphate content varies from 1.374 - 3.986 mg/L in Ihalagama-East and water-soluble phosphate was not detected in Eldeniya-East, indicating a very low range and suggesting that the water samples are less contaminated with phosphate-containing substances. Considerably high values in the range of 1.24 - 279.00 mg/L for Ihalagama-east and 59.5 mg/L - 168.0 mg/L for Eldeniya-East, are obtained for the nitrate content where most of them are beyond the safe level of drinking water, 50 mg/L. The soil pH in all the samples falls within the acidic range, varying from 2.99 - 6.73 in Ihalagama-East and 3.07 – 6.68 in Eldeniya-East. Most of the soil samples contain high nitrate contents, indicating significant contamination. The percentage soil organic matter content varies between 0.60% and 13.27% in both areas. Many fertile agricultural soils typically have an organic matter content ranging from 3% - 6% revealing that most of the samples are beyond the standard levels. The distribution of water-soluble and extractable cations does not exhibit a wide range. According to the findings, though two Grama Niladhari Divisions are selected, they also display a huge variation. This reveals the importance of mapping to address contaminations, effects of natural disasters which lead to changes in the studied water and soil quality parameters.

The role of abiotic and biotic factors within influencing macroinvertebrate communities in a subtropical eutrophic reservoir with thermal stratification

ABSTRACT In this study, we investigated the plankton, water, and macroinvertebrates in Nanwan Reservoir, a subtropical eutrophic reservoir with thermal stratification. We evaluated the status of macroinvertebrate communities and explored the relationships between macroinvertebrate community status and both abiotic and biotic factors. This reservoir exhibited the worst water quality and a high risk of algal blooms in the autumn, whereas it had the best water quality in the spring. The presence of thermal stratification adversely affected macroinvertebrate communities, leading to decreases in species richness, abundance, and diversity. The water characteristics and dominant macroinvertebrate species confirmed that the reservoir was experiencing progressive eutrophication. During the thermal stratification period, the reservoir exhibited a worse status of macroinvertebrate communities, accompanied by an abundance of plankton. The results of PLSR and the Spearman rank test revealed that several abiotic factors, such as water temperature, chlorophyll-a, soluble phosphate, pH, and transparency, as well as biotic factors including the abundance of protozoans, Cyanobacteria, phytoplankton, Bacillariophyta, and Euglenophyta, were the most important factors affecting macroinvertebrate communities. The results of PLS-SEM revealed that both abiotic factors and biotic factors had non-negligible effects on the status of macroinvertebrate communities, with higher effect from abiotic factors compared to biotic factors.

Ultralong Nanowires of Cadmium Phosphate Hydroxide Synthesized Using a Cadmium Oleate Precursor Hydrothermal Method and Sulfidation Conversion to Ultralong CdS Nanowires.

Ultralong nanowires with ultrahigh aspect ratios exhibit high flexibility, and they are promising for applications in various fields. Herein, a cadmium oleate precursor hydrothermal method is developed for the synthesis of ultralong nanowires of cadmium phosphate hydroxide. In this method, water-soluble cadmium salt is used as the cadmium source, water-soluble phosphate is used as the phosphorus source, and sodium oleate is adopted as a reactant to form cadmium oleate precursor and as a structure-directing agent. By using this method, ultralong nanowires of cadmium phosphate hydroxide are successfully synthesized using CdCl2, sodium oleate, and NaH2PO4 as reactants in an aqueous solution by hydrothermal treatment at 180 °C for 24 h. In addition, a new type of flexible fire-resistant inorganic paper with good electrical insulation performance is fabricated using ultralong nanowires of cadmium phosphate hydroxide. As an example of the extended application of this synthetic method, ultralong nanowires of cadmium phosphate hydroxide can be converted to ultralong CdS nanowires through a convenient sulfidation reaction. In this way, ultralong CdS nanowires are successfully synthesized by simple sulfidation of ultralong nanowires of cadmium phosphate hydroxide under mild conditions. The as-prepared ultralong nanowires of cadmium phosphate hydroxide are promising for applications as the precursors and templates for synthesizing other inorganic ultralong nanowires and have wide applications in various fields.

The effect of deicing reagents on soil properties of the roadside lawns in Novosibirsk

The aim of the study was to evaluate the effect of deicing reagents on soil properties of the roadside lawns in Novosibirsk. Location and time of the study. Roadside lawns and a public green square in the central part of the Novosibirsk city. Field and laboratory work was performed in late 2023–early 2024. Methods. Soil samples were analyzed according to the following methods: preparation of aqueous extract was done at the ratio of soil:solution of 1:5; determination of specific electrical conductivity and water pH was performed using the electrodes HI763123 and ESC-10603, respectively; the content of water-soluble sulfates was measured with precipitation of sulfate ions by barium chloride and determination of barium sulfate by turbidimetric method; water-soluble sodium was measured by atomic absorption spectrometer with flame atomization Kvant-2A; water-soluble chlorides were measured by ion-selective electrode Econix ECOM-Cl; and water-soluble phosphates were measured by molybdenum-blue spectrophotometric method. The statistical processing of the data was carried out using the principal components analyzis, as well as by variation, regression, correlation and variance analyses. Results. Application of deicing reagents (DR) altered most significantly the content of water-soluble sodium and chlorine in the urban soils of roadside lawns, the values of which reached as high as 443 mg Na/kg and 511 mg Cl/kg. Sulfate and phosphate concentrations depended on the DR application to a much lesser extent. The relationship of chlorine content with the sodium one was described by a simple linear regression equation with a coefficient of determination (R2) equal to 0,92: Cl = 1,503 × Na – 34,655, where Cl and Na concentrations are presented in mg/kg. A close positive relationship (R2 = 0,87) was also found between the sum of all four analyzed ions (SI) and specific electrical conductivity (EC), described by the linear equation SI = 0,0078 × EC – 0,985, where SI (sum of Na+, Cl–, SO42–, and PO42– ions) is represented in cmol(eq)/kg, and EC in μS/cm. Conclusions. In the urban soils of roadside lawns, as compared to the central part of the public square, a significant increase in the content of water-soluble sodium and chlorine was found: 7–24 times and 30–80 times, respectively. The increase in the concentration of these elements was associated with a 3,3-fold increase in the value of specific electrical conductivity (which characterizes the general level of soil salinization with easily soluble salts) and a change in the reaction from "slightly alkaline" to "moderately alkaline". Such significant changes in the chemical properties of the urban roadside soils are caused by the DR use, which may result in the suppression of growth and development of plants, especially tree species less adapted to salt pollution, eventually leading to their dying-off.

Deposition of insoluble calcium phosphate layers by combining finely dispersed calcium hydroxide sols with soluble phosphates

Carbonate containing materials are subject to severe weathering. Traditional formulations of stone strengtheners have low compatibility with the original material and further they contain VOCs (volatile organic compounds), which endanger human health and the environment. This study explores the high potential of novel treatments based on water-soluble phosphates used as an agent to react with calcium carbonate (CaCO3) to form an insoluble film of calcium phosphate in the pore space of the treated material. Pretreatments with nanolime suspensions ensure greater availability of calcium ions and reduce the consumption of the original material in the reactions. An alkaline environment is required to promote the conversion of the CaCO3 components to hydroxyapatite-like compounds. Based on experiments in aqueous solutions, different sources of phosphate ions could be examined and compared for the development of effective treatments to apply on different test specimens. To implement the treatments, barium phosphate solutions were investigated. Important aspects of this research are the use of green solvents and the search of components that avoid the formation of byproducts, to increase the efficiency of the chemical reactions and reduce possible negative effects on the operator, the environment and the very same built heritage material. The developed treatments are a valuable alternative to the traditional methods, as it follows an improvement in the material properties without affecting the moisture transport within it and allows the evenly reaction of the strengthened material to external physical and mechanical stresses without creating internal tension between the grains.

Study on the occurrence state of main components of phosphogypsum dihydrate and its impurity distribution.

The dihydrate phosphoric acid process is the mainstream technique. However, the phosphogypsum (PG) produced contains high levels of impurities such as phosphorus and fluorine, severely constraining its valorization. In order to elucidate the occurrence patterns of phosphorus and fluorine impurities in PG, this study employed analytical methods including XRF, XRD, AMICS (Automated Mineralogy Integrated with Chemistry System), XPS, and chemical element balance analysis. We investigated the occurrence states of phosphorus, fluorine, silicon, iron, and aluminum elements in PG from wet-process phosphoric acid production, as well as the distribution characteristics of phosphorus and fluorine impurities. Additionally, we utilized Density Functional Theory (DFT) calculations to determine the binding energies of major minerals with water-soluble phosphate and fluoride groups, and analyzed the zeta potentials of gypsum and quartz mineral surfaces. The results indicate that the main mineral phases in PG are gypsum, quartz, potassium silicate minerals, aluminosilicate minerals, and hematite, predominantly occurring in monomineralic forms. Phosphorus impurities primarily exist in calcium silicate and hematite minerals, while fluorine is mainly associated with gypsum and potassium silicate minerals. DFT calculations demonstrate strong binding energies between calcium silicate and hematite minerals with PO4 3-, as well as between gypsum and quartz minerals with F-. The acidic conditions in the separation tank during wet-process phosphoric acid production may contribute to the distinctive distribution characteristics of phosphorus and fluorine impurities in PG.

Synthesis and biological evaluation of structurally diverse 6-aryl-3-aroyl-indole analogues as inhibitors of tubulin polymerization

The synthesis and evaluation of small-molecule inhibitors of tubulin polymerization remains a promising approach for the development of new therapeutic agents for cancer treatment. The natural products colchicine and combretastatin A-4 (CA4) inspired significant drug discovery campaigns targeting the colchicine site located on the beta-subunit of the tubulin heterodimer, but so far these efforts have not yielded an approved drug for cancer treatment in human patients. Interest in the colchicine site was enhanced by the discovery that a subset of colchicine site agents demonstrated dual functionality as both potent antiproliferative agents and effective vascular disrupting agents (VDAs). Our previous studies led to the discovery and development of a 2-aryl-3-aroyl-indole analogue (OXi8006) that inhibited tubulin polymerization and demonstrated low nM IC50 values against a variety of human cancer cell lines. A water-soluble phosphate prodrug salt (OXi8007), synthesized from OXi8006, displayed promising vascular disrupting activity in mouse models of cancer. To further extend structure-activity relationship correlations, a series of 6-aryl-3-aroyl-indole analogues was synthesized and evaluated for their inhibition of tubulin polymerization and cytotoxicity against human cancer cell lines. Several structurally diverse molecules in this small library were strong inhibitors of tubulin polymerization and of MCF-7 and MDA-MB-231 human breast cancer cells. One of the most promising analogues (KGP591) caused significant G2/M arrest of MDA-MB-231 cells, disrupted microtubule structure and cell morphology in MDA-MB-231 cells, and demonstrated significant inhibition of MDA-MB-231 cell migration in a wound healing (scratch) assay. A phosphate prodrug salt, KGP618, synthesized from its parent phenolic precursor, KGP591, demonstrated significant reduction in bioluminescence signal when evaluated in vivo against an orthotopic model of kidney cancer (RENCA-luc) in BALB/c mice, indicative of VDA efficacy. The most active compounds from this series offer promise as anticancer therapeutic agents.

Self-Assembly Properties of an Amphiphilic Phosphate Ester Prodrug Designed for the Treatment of COVID-19

PF-07304814 is a water-soluble phosphate ester prodrug of a small molecule inhibitor for the SARS CoV-2 3CL protease designed for the treatment of COVID-19. The amphiphilicity and self-assembly behavior of the prodrug was investigated computationally and experimentally via multiple orthogonal techniques to better design formulations for intravenous infusion. The self-assembly of PF-07304814 into micellar structures enabled an increase in the solubility of lipophilic impurities by up to 1900x in clinically relevant formulations. The observed solubilization could help extend the drug product shelf-life and in use stability through inhibition of precipitation, without the need for solubilizing excipients. The work presented in this manuscript provides a roadmap for the characterization of prodrug self-assembly and highlights the potential for prodrug modifications to enhance solubility of both active ingredients and impurities and to extend drug product shelf-life.

In vitro and in vivo pharmacological profile of OPC-61815, a water-soluble phosphate ester pro-drug of tolvaptan

Tolvaptan is an orally active vasopressin V2 receptor antagonist and used for the treatment of volume overload in some disease as an aquaretic. Tolvaptan sodium phosphate (OPC-61815) is a pro-drug of tolvaptan that was designed to improve water solubility and enable intravenous use. The conversion of OPC-61815 to tolvaptan was evaluated for in vitro and in vivo pharmacokinetic studies. The pharmacodynamics of OPC-61815 were evaluated for in vitro receptor binding affinity, in vivo aquaretic and anti-edematous action. The solubility of OPC-61815 in water at 25 °C was 72.4 mg/mL and more than 100,000 times the solubility of tolvaptan. OPC-61815 was hydrolyzed to tolvaptan by human tissue S9 fractions and main enzyme of hydrolysis was alkaline phosphatase. After intravenous administration of OPC-61815 to rats and dogs, tolvaptan was detected in plasma within 5 min and the bioavailability of tolvaptan was 57.7% and 50.9%, respectively. Binding affinity of OPC-61815 for the human V2 receptor was 1/14 weaker than that of tolvaptan. OPC-61815 exerted dose-dependent aquaretic action in rats and dogs and a corresponding anti-edematous action in rat edema models. These results suggest that OPC-61815, a water-soluble phosphate ester pro-drug of tolvaptan, is an effective aquaretic by converting to tolvaptan after intravenous administration.

Luteolin Phosphate Derivatives Generated by Cultivating Bacillus subtilis var. Natto BCRC 80517 with Luteolin.

Luteolin (LUT), a plant-derived flavone, exhibits various bioactivities; however, the poor aqueous solubility hampers its applications. Here, we revealed bioconversion of LUT by Bacillus subtilis BCRC 80517, yielding three water-soluble phosphate conjugates. These derivatives were identified as luteolin 4'-O-phosphate (L4'P), luteolin 3'-O-phosphate (L3'P), and luteolin 7-O-phosphate (L7P) by LC-ESI-MS/MS and NMR. Besides, we found that Bacillus subtilis BCRC 80517 was able to convert different levels of LUT but showed a limited conversion rate. By observing bacterial morphology with transmission electron microscopy and confocal fluorescence microscopy, we found that LUT disrupted the bacterial membrane integrity, which explained the incomplete conversion. Additionally, we revealed a spontaneous intramolecular transesterification of L4'P to L3'P, the thermodynamically more stable form, under acidic conditions and proposed the possible mechanism involving a cyclic phosphate as the intermediate. This study provides insight into development of a potent structural modification strategy to enhance the solubility of LUT through biophosphorylation.

UJI AKTIVITAS BAKTERI PELARUT FOSFAT TERHADAP KELARUTAN FOSFAT PADA TANAH SALIN

The high salt content in saline soils is the main cause of low salinity soil fertility, especially phosphorus nutrients. The application of phosphate-solubilizing bacteria in saline soil is one method to increase phosphate availability in saline soils. The study consisted of two tests, namely (1) qualitative and quantitative testing of phosphate-solubilizing bacteria in saline conditions and (2) testing of the activity of phosphate solubilizing bacteria in saline soil. This study used Pseudomonas sp. and Bacillus valezensis (Soil Biology Laboratory collection), Inceptisol saline soil from Banongan and Agel Situbondo. The study aimed to determine the activity of phosphate-solubilizing bacteria on the solubility of phosphate in saline soil. The results showed that: (1) Pseudomonas sp. and Bacillus valezensis have a solubility index of 1.25 to 2.68 on solid Pikovskaya medium with some NaCl concentration. Quantitatively test on liquid Pikovskaya medium, water-soluble phosphate concentration about 4.84 ppm to 14.18 ppm and soluble phosphate (extract Bray) between 15.91 ppm to 21.58 ppm. In addition, (2) on saline soil showed that Pseudomonas sp. and Bacillus valezensis could increase phosphate availability by 11.61% to 72,89%. Based on the study results, the genus Pseudomonas sp. and Bacillus valezensis have the potential to increase phosphate availability in saline soils.

Abstract 6206: Discerning vasculature destruction caused by novel vascular disrupting agents examined by optical and multispectral optoacoustic imaging

Abstract Tumor growth requires a functioning vascular network and offers an attractive therapeutic target. The invasive proliferating neovasculature of tumors lacks pericyte support and exhibits increased permeability thereby offering a unique, potentially selective target for anticancer therapy. Most vascular disrupting agents (VDAs) inhibit microtubule formation, causing rapid morphological changes in endothelia cells resulting in dramatically increased vessel permeability, cellular detachment, vessel occlusion, and vessel wall damage [doi: 10.3390/molecules26092551]. Highly vascular kidney tumors are expected to be particularly sensitive to VDAs. We are evaluating OXi8007, a water soluble indole phosphate pro-drug derivative of the first generation VDA combretastatin. The prodrug OXi8007 is stable in saline but releases active OXi8006 is the presence of alkaline phosphate. Preliminary pharmacokinetic data benchmarked using 13C-labeled OXi8006 and OXi8007 show rapid vascular clearance and conversion to the glucuronide conjugate in vivo. Doses up to 700 mg/kg were tolerated by mice. Luciferase-expressing RENCA tumor cells were implanted orthotopically in the right kidney capsule of syngeneic BALB/c mice. Bioluminescence Imaging (BLI) was applied weekly to assess tumor growth and acute response to OXi8007. Following addition of luciferin substrate subcutaneously BLI signal from the tumor reached a maximum within 10 minutes. When BLI was repeated 4 hrs after 250 or 350 mg/kg OXi8007 IP, the generated signal was <1% of baseline signal indicating acute vascular disruption. Multispectral Optoacoustic Tomography (MSOT) revealed matching acute changes in tumor vascular oxygenation and additionally showed distinct heterogeneity. An oxygen gas breathing challenge indicated lower oxygen saturation in the tumor following treatment. Histology showed massive hemorrhage following both doses. BLI signal recovered after 1 to 2 days and repeated administration of OXi8007 again caused acute vascular shutdown. These results match previous observations in breast tumor models [doi: 10.1016/j.canlet.2015.08.021] indicating opportunities for therapeutic application. Citation Format: Hashini I. Wanniarachchi, Regan Schuetze, Lorena Arango, Khagendra Hamal, Graham J. Carlson, Cyprian Pavlich, Yuling Deng, Mary L. Trawick, Kevin G. Pinney, Li Liu, Ralph P. Mason. Discerning vasculature destruction caused by novel vascular disrupting agents examined by optical and multispectral optoacoustic imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6206.

Water soluble reactive phosphate (SRP) in atmospheric particles over East Mediterranean: The importance of dust and biomass burning events

The importance of dust and biomass burning episodes on the atmospheric concentration of water-soluble reactive phosphate (SRP) was determined in the eastern Mediterranean. SRP was measured with a new rapid real-time automated analytical system with a time resolution of a few minutes per sample and with an extremely low detection limit. The average atmospheric concentration of SRP during the sampling campaign was estimated at 0.35 ± 0.25 (median 0.30) nmol P m−3. The maximum concentration of SRP (3.08 nmol P m−3) was recorded during an intense dust episode, and was almost ten times higher than the campaign average, confirming that Saharan dust was an important primary source of bioavailable P to the eastern Mediterranean, especially during the spring period when 60% of the events occurred. Predicted increases in the frequency and intensity of dust storms in the area will enhance the role of the atmosphere as a source of bioavailable P for the Mediterranean marine ecosystem. During the warm period, when Northerly winds prevailed, biomass burning processes contributed significantly to soluble phosphorus delivered from atmospheric sources to the eastern Mediterranean. These inputs during warm periods are especially important for the Eastern Mediterranean, where biological productivity is strongly limited by nutrient availability.

The improvement of the water-resistance of the phosphogypsum by adding waste metallurgical sludge

The solution of the phosphogypsum ecological problem consist in its utilisation. The purpose of the study is to improve the water-resistance of the phosphogypsum to make it a suitable and green alternative to cement. Hence, a waste metallurgical sludge from a ship-repairing yard was added in amounts of 0.1 to 0.5%. The modifier reduced the harmful water-soluble phosphate by 15 times and maintained the high hydration degree of the specimens. The compressive strength was tested for both the dry and the previously immersed in water specimens. The addition of 0.1–0.3% metallurgical sludge improved their water-resistance by 2 times. • The content of soluble phosphate impurities in PG is reduced by the MS by 15 times. • The MS modifier enhances the water resistance of the PG specimens by 2 times. • The proposed composite material is a completely ecological solution. • The MS additive gives new possibilities to PG, improving its applicability.

Phosphorus solubilizing bacteria Bacillus thuringiensis and Pantoea ananatis simultaneously promote soil inorganic phosphate dissolution and soil Pb immobilization

The phytoavailability of lead (Pb) can be greatly reduced when Pb forms stable phosphate compounds in soil. This study employed broth culture, soil incubation, and pot experiments to investigate whether phosphate solubilizing bacteria (PSB) could effectively immobilize soil Pb through dissolution of insoluble inorganic P compounds. The results showed that both Bacillus thuringiensis GL-1 (GL-1) and Pantoea ananatis HCR2 (HCR2) could use Ca3(PO4)2, FePO4, and AlPO4 as the sole P resource and significantly increase water-soluble phosphate concentrations, which reached 555.84 and 392.66 mg/L, 13.82 and 72.06 mg/L, and 93.29 and 92.87 mg/L, respectively. The minimum pH of these culture media was reduced to 3.93 and 4.02, 3.37 and 3.40, and 2.86 and 2.89, respectively. Compared with the control, inoculation of GL-1 to artificially Pb-contaminated soil significantly reduced Fe–P, Al–P, Olsen-P, and NH4NO3-extractable Pb concentrations by 13.70%, 15.84%, 13.29%, and 33.61%, respectively, while reduced those by 23.75%, 53.43%, 11.66%, and 47.54% in the case of HCR2. Similarly, inoculation of GL-1 or HCR2 significantly reduced Fe–P concentrations of the historically metal-contaminated acidic soil by 50.00% and 46.73%, respectively. The NH4NO3-extractable soil Pb concentrations also decreased, which was only significant in soil inoculated with GL-1. Pot experiment found that inoculation of GL-1 and HCR2 decreased soil Pb phytoavailability and consequently inhibited its uptake by lettuce (Lactuca sativa L.). Meanwhile, the inoculation of HCR2 significantly promoted plant growth and reduced shoot Pb concentrations when grown in artificially Pb-contaminated soil. The results suggest that inoculation of GL-1 and HCR2 could be applied for remediating Pb-contaminated soils.

Analysis of the solubility of phosphate rock from Aipe (Colombia) via formation of 2Na-EDTA complex

Phosphate rock (PR) is the main source of phosphorous used in fertilizers for Colombian soils. In many regions of Colombia, PR is applied directly to the soil, which affects eutrophication problems and phosphorus losses due to runoff, because to the low solubility of phosphorus in this georesource. In this article, phosphate rock samples from Colombia were treated with ethylenediamine tetra-acetic acid disodium salt dihydrate (2Na-EDTA) at different concentrations. PR obtained from the Media Luna Mine, located in Aipe, Huila (Colombia), was characterized using Infrared Spectroscopy, X-ray Diffraction and Scanning Electron Microscopy. Carbonate fluorapatite Ca9.74(PO4)5.45F2.05(CO3)0.53 (0.5%–61.5 %), hydroxyapatite - Ca5(PO4)3OH (26.6 %–84.0 %) and quartz- SiO2 (13.2 %) were the minerals found in the largest composition in the two samples of PR. The PR was crushed to powder (~125 μm) and it was treated with disodium EDTA dihydrate solutions at different concentrations [0.0025–0.1000 M]. Water-soluble phosphate was determined by UV–Vis spectrophotometry based on the ASTM -4500P method. The modified absolute solubility index (ASI*) was calculated for each EDTA treatment used in the phosphate rock, considering the total phosphorus solubilized in H2SO4 (40 % v/v) at 30 °C. The statistical analysis showed that there were significant differences between the treatments used, where (16.87 %) was presented highest ASI* for the treatment with 2Na-EDTA (0.353 M).

A novel photocrosslinked phosphate functionalized Chitosan-Sr5(PO4)2SiO4 composite hydrogels and in vitro biomineralization, osteogenesis, angiogenesis for bone regeneration application

The natural polysaccharide-based hydrogels have gained significant interest to use as 3D scaffolds for bone repair and reconstruction owing to their excellent biocompatibility, biosafety, and biodegradability. Yet, these hydrogels have major obstacles in terms of insufficient properties such as mechanical, osteogenic, angiogenic, and biomineralization. Therefore, this study mainly aims to develop an innovative water-soluble phosphate functionalized chitosan (CSMAP) through consequent modification with methacrylic anhydride (MA), then alteration by phosphonopropionic acid (P). Further, a novel photocrosslinked composite hydrogel was fabricated with a combination of CSMAP and synthesized strontium phosphosilicate (SPS, Sr5(PO4)2SiO4) bioceramic nanoparticles with a photoinitiator under UV irradiation. The various concentrations of nanosized SPS particles (0.5, 2.5, 5, and 10 mg/mL) were incorporated into the CSMAP matrix and the swelling, mechanical, morphological, physiochemical, osteogenic, angiogenic properties were investigated. The CSMAP-SPS composite hydrogels possessed a well-arranged porous network structure. The composite hydrogel was restricted to swell in distilled water with the increased concentration of SPS particles. The compressive strength and modulus of CSMAP hydrogel were improved by the inclusion of SPS particles. The bioactive Sr, P, and Si ions were released from CSMAP-SPS hydrogels in a sustained and controlled manner at a non-toxic level. The composite hydrogels promoted in vitro amorphous apatite deposition, revealing a superior biomineralization activity. In vitro results demonstrated that the composites hydrogels showed no toxicity to preosteoblast MC3T3-E1 cells, induced MC3T3-E1 osteogenic differentiation with detection of bsp, ocn and opn osteogenic genes, and also promoted the endothelial tube formation with increased capillary length, branch points, and angiogenic gene vegf expression. Thus, the obtained results proved that the fabricated novel CSMAP-SPS hydrogel could act as an attractive candidate for bone regeneration.

A sensitive method for analyzing fluconazole in extremely small volumes of neonatal serum

BackgroundThe need for a large volume of serum sample significantly reduces the feasibility of neonatal pharmacokinetic studies in daily practice, which must often rely on scavenged or opportunistic sampling. This problem is most apparent in preterm newborns, where ethical and practical considerations prohibit the collection of large sample volumes. Most of the fluconazole analysis assays published thus far required a minimum serum sample of 50 to 100 μL for a single assay. The purpose of the present study was to develop and validate a sensitive method requiring a smaller sample volume (10 μL) to satisfy clinically relevant research requirements.MethodsFollowing simple protein precipitation and centrifugation, the filtrated supernatant was injected into a liquid chromatography system and separated with a C18 reverse-phase column. Fluconazole and the internal standard (IS, fluconazole-d4) were detected and quantified using tandem mass spectrometry. The method was validated with reference to the Food and Drug Administration’s Guidance for Industry. Accuracy and precision were evaluated at six quality control concentration levels (ranging from 0.01 to 100 μg/mL).ResultsInvestigated calibration curves were linear in the 0.01–100 μg/mL range. Intra- and inter-day accuracy (− 7.7 to 7.4%) and precision (0.3 to 6.0%) were below 15%. The calculated limit of detection and the lower limit of quantification (LLOQ) was 0.0019 μg/mL and 0.0031 μg/mL, respectively. Fluconazole in the prepared samples was stable for at least 4 months at − 20 °C and − 80 °C. This method was applied to analyze 234 serum samples from ten neonates who received fosfluconazole, a water-soluble phosphate prodrug of fluconazole which converts to fluconazole in the body, as part of a pharmacokinetic study using daily scavenged laboratory samples. The median (range) concentration up to 72 h after fosfluconazole administration was 2.9 (0.02 to 26.8 μg/mL) μg/mL, which was within the range of the calibration curve.ConclusionFluconazole was able to be detected in an extremely small volume (10 μL) of serum from neonates receiving fosfluconazole. The method presented here can be used to quantify fluconazole concentrations for pharmacokinetic studies of the neonatal population by using scavenged samples.

Effect of phosphorus-coupled nitrogen fertigation on clogging in drip emitters when applying saline water

Emitter clogging risk might be enhanced by the specific fertigation practice when applying saline water. Two stages of on-site drip irrigation experiments applying saline water were conducted to investigate the effects of the phosphorus (P) fertigation and combined P and nitrogen (N) fertigation and the water salinity on emitter clogging when using a plain channel emitter and a labyrinth emitter. During stage one, the water-soluble phosphate fertilizers monoammonium phosphate (MAP), diammonium phosphate (DAP), and urea phosphate (UP) were tested in comparison with a control treatment without fertigation (CK). During stage two, four combined P and N fertigation practices were tested by mixing one phosphate fertilizer (MAP or DAP) with one N fertilizer (urea (U) or ammonium sulphate (AS)). Four levels of water electrical conductivity measuring about 0.5 (groundwater, G), 2 (S2), 4 (S4), and 6 (S6) dS m−1 were tested at both experimental stages. The discharge rates of the emitters were measured following every other two fertigation events during stage one and following each fertigation event for stage two. At the end of the experiments, several representative emitters were sampled to measure the dry weight and the chemical constituents of the clogging substances in the emitters. The results demonstrated that the P fertigation with a weak or a slightly stronger acidic fertilizer such as MAP or UP reduced the emitter clogging effectively during groundwater application. For saline water application, the emitter clogging clearly increased with the water electrical conductivity. Phosphorus-coupled nitrogen fertigation accelerated the precipitation of phosphate sediments greatly when either groundwater or saline water was applied. In fact, the precipitation of phosphate sediments exceeded 80% of the dry weight in the emitters under saline water irrigation. Rapid development of emitter clogging occurred for both types of emitters when saline water with electrical conductivity higher than 4 dS m−1 was applied under phosphorus-coupled nitrogen fertigation. The phosphorus-coupled nitrogen drip fertigation should be applied with cautious when applying saline water with electrical conductivity higher than 4 dS m−1. Fertigating with nitrogen fertilizers along with acid phosphate fertilizers together is a promising way to alleviate the emitter clogging caused by the ion components in saline water.