Free Phosphate Research Articles

Carbonate‐Associated Phosphate (CAP) Indicates Elevated Phosphate Availability in Neoarchean Shallow Marine Environments

AbstractPhosphorus is essential for cell biology, yet scarce in modern marine environments wherein free phosphate is consumed by life or titrated by calcium to form apatite minerals. The environmental conditions under which the early biosphere emerged and phosphorus was integrated throughout biochemistry is yet unknown. We measured the phosphate concentrations of 2.8–2.5 Ga shallow marine carbonate facies across six Neoarchean shelf‐ramp environments. We found that the P/Ca ratios of Neoarchean stromatolites, micrites, and crystal fans were >4‐fold to 12‐fold more enriched in carbonate‐associated phosphate than modern marine coral skeletons and abiotic Phanerozoic carbonates. Our results support the view that Archean productivity was limited by the availability of electrons rather than phosphate or other nutrients, and help explain why phosphorus is so central to the molecules, metabolisms, and bioenergetics observed in cells.

Binder free cobalt iron phosphate thin films as efficient electrocatalysts for overall water splitting

Designing nanostructure based robust catalyst for the electrochemical water splitting is the great task in the energy conversion field to accomplish high electrical conductivity, low overpotential and long lasting activity. Herein, the electrochemical overall water splitting is reported by using the hydrothermally synthesized binder free cobalt iron phosphate thin films on low cost stainless steel substrates as a conducting backbone for the first time. The effect of composition ratio variation of cobalt and iron was studied on the structural, compositional, morphological, and surface electronic properties by conducting various characterizations which results in amorphous hydrous cobalt iron phosphate having mesoporosity. The as synthesized cobalt iron phosphate having composition ratio (50:50 of Co:Fe) exhibits excellent electrochemical OER and HER catalytic water splitting performance. Best performing electrode exhibits smallest overpotentials of 251.9 mV and 55.5 mV for OER and HER respectively at 10 mA/cm2 current density. To split water molecule into the H2 and O2 by overall water splitting in same alkaline medium, the potential of 1.75 V was required after long duration (100 h) catalysis. Overall analysis confirms the cobalt iron phosphate thin films are outstanding and robust for the hydrogen production as clean renewable energy source.

Template and binder free 1D cobalt nickel hydrogen phosphate electrode materials for supercapacitor application

Herein, we synthesized 1D bimetallic hydrogen phosphate [CoxNix(HPO4)] nanorods by using a simple and effective chemical bath deposition method for supercapacitor applications. The prepared CoxNix(HPO4) was analyzed by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) pattern. The surface morphology was envisaged by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. The porous nature and surface area of the materials were characterized by nitrogen sorption isotherm and a high specific surface area of 153 m2 g−1 was found to be for Co0.75Ni0.25(HPO4). The Co0.75Ni0.25(HPO4) displays a maximum specific capacity of 475 mA h g−1 at 1 A g−1 in a three-electrode configuration using 3 M KOH as the electrolyte. Co0.75Ni0.25(HPO4) exhibits almost 94.8% of its initial specific capacity over 5000 GCD cycles at 10 A g−1. Furthermore, the fabricated asymmetric supercapacitor (ASC) with Co0.75Ni0.25(HPO4) and activated carbon (AC) showed a high specific capacitance of 182.5F g−1 at 0.5 A g−1. The ASC device delivered a maximum energy density of 64.88 Wh kg−1 at a power density of 800 W kg−1.

A comparative study on the density and seasonal variations of rotifer and copepod fauna in a pond of Tripura, India with a note on water quality parameters

A Comparative study was carried out in a pond of Tripura to observe the density and seasonal succession of rotifer and copepod fauna and the observation recorded 26 species of rotifer and 6 species of copepod fauna. Percentage composition of different families as well as percentage composition of each species in the recorded total rotifer and copepod fauna was also noted. Rotifer fauna showed maximum density in the winter and minimum density during summer. On the contrary, copepod fauna showed maximum density in the summer and minimum density in monsoon season. Rotifer fauna showed significant positive correlation with water temperature, free carbon dioxide, total alkalinity, nitrate-nitrogen, phosphate phosphorus and negative correlation with transparency. On the contrary, copepod fauna showed positive correlation with water temperature and pH and negative correlation with dissolved oxygen, total alkalinity and nitrate nitrogen. The observation infers that the densities of rotifer and copepod fauna varies with seasons which might be the dynamic nature of the aquatic ecosystem and might also be due to optimal condition in the water quality parameters of the studied pond ecosystem.

Cortisol and Phosphate Homeostasis: Cushing's Syndrome Is Associated With Reversible Hypophosphatemia.

ObjectivesThe influence of hypercortisolism on phosphate homeostasis is relatively unknown. A few previous studies have reported on patients with Cushing’s syndrome (CS) with hypophosphatemia in whom serum phosphate normalized after initiation of treatment for CS. We aimed to investigate the prevalence of hypophosphatemia in CS, the association between the degree of hypercortisolism and serum phosphate and the change in serum phosphate after remission of CS. We compared the prevalence of hypophosphatemia in CS with the prevalence in the population-based Rotterdam Study (RS).MethodsPatients diagnosed with CS and treated at the Department of Endocrinology of Erasmus MC in the period of 2002-2020 were included and data was collected on age at diagnosis, sex, serum phosphate, calcium and potassium levels, kidney function and BMI. Using multivariate linear regression, we analyzed the association between 24h urinary free cortisol excretion (UFC) and serum phosphate. Changes in serum phosphate and covariates were tested with a repeated measurement ANOVA, using mean levels of laboratory values for the periods before remission, and 0-14 days and 15-180 days after remission.ResultsHypophosphatemia before treatment was present in 16% of the 99 CS patients with data on serum phosphate, 24h UFC and covariates. In comparison, the prevalence of hypophosphatemia in RS was 2.0-4.2%. Linear regression showed a negative association between the level of UFC and serum phosphate at diagnosis, which remained significant after adjusting for covariates [β -0.002 (95%CI -0.004; -0.0004), p=0.021]. A subset of 24 patients had additional phosphate measurements at 0-14 days and 15-180 days after remission. In this subgroup, serum phosphate significantly increased from 1.03 ± 0.17 mmol/L prior to remission to 1.22 ± 0.25 mmol/L 15-180 days after remission (p = 0.008). BMI decreased after remission [-1.1 kg/m2, (95%CI -2.09 to -0.07), p=0.037]. Other covariates did not show an equivalent change over time.ConclusionIn this retrospective study, we found that 16% of patients with CS had hypophosphatemia. Moreover, serum phosphate was related to the level of cortisoluria and increased after remission of CS. Potential underlying mechanisms related to urinary phosphate excretion and possibly involving FGF23, BMI and parathyroid hormone levels should be further explored.

Coupled catalytic dephosphorylation and complex phosphate ion-exchange in networked hierarchical lanthanum carbonate grafted asymmetric bio-composite membrane

The remediation of non-reactive phosphate pollutants in the aquatic system is essential for protecting the ecological niche. In this work, a highly robust protein nanoparticles networked rare-earth metal carbonate-grafted bio-composite membrane (abbreviated as REMC) was fabricated via chemical crosslinking of three-dimensional (3D) hierarchical lanthanum carbonate (mREM) and casein nanoparticles (CsNPs) for selective rejection of non-reactive phosphates. The main components of the REMC membrane are mREM and CsNPs, which were prepared via SDS/CTAB templated homogeneous precipitation and the coacervation/desolvation hybrid method, respectively. The active lanthanum ion (La3+) on the 3D spherulitic surface of mREM exhibited excellent phosphate adsorption capacity (maximum adsorption capacity was 358 mg.g−1) across a wide pH range and in a multi-ionic environment. A series of batch testing and characterizations revealed that the active La3+ and dominating phosphate centers in the REMC membrane framework enable non-enzymatic phosphatase-like activity, cleaving the phosphate ester bond of organic phosphates and releasing free phosphate anions. These released phosphate ions are retained in the REMC membrane via an ion exchange mechanism, where they contribute to improved phosphate removal capacities. Furthermore, CsNPs have a dual function in the membrane, acting as a matrix in the REMC membrane framework and contributing to phosphate ion sequestrations in a synergistic manner. The catalysis of para-nitrophenyl phosphates (pNPP) to paranitrophenol (pNP) in a sequential dephosphorylation by REMC offers an estimate of reaction kinetics and elucidates the underlying mechanism of improved phosphate selectivity in a multi-ionic environment. Furthermore, phosphate specificity, homogeneous binding capacity, reusability, and visual observation of REMC membrane saturation binding direct it's useful economic, industrial applications in aqueous phosphate contaminant removal, which could be beneficial for the active recovery of the aquatic ecosystem.

Wells\u2013Dawson phosphotungstates as mushroom tyrosinase inhibitors: a speciation study

In order to elucidate the active polyoxotungstate (POT) species that inhibit fungal polyphenol oxidase (AbPPO4) in sodium citrate buffer at pH 6.8, four Wells–Dawson phosphotungstates [α/β-PV2WVI18O62]6− (intact form), [α2-PV2WVI17O61]10− (monolacunary), [PV2WVI15O56]12− (trilacunary) and [H2PV2WVI12O48]12− (hexalacunary) were investigated. The speciation of the POT solutions under the dopachrome assay (50 mM Na-citrate buffer, pH 6.8; L-3,4−dihydroxyphenylalanine as a substrate) conditions were determined by 183W-NMR, 31P-NMR spectroscopy and mass spectrometry. The intact Wells–Dawson POT [α/β-PV2WVI18O62]6− shows partial (~ 69%) disintegration into the monolacunary [α2-PV2WVI17O61]10− anion with moderate activity (Ki = 9.7 mM). The monolacunary [α2-PV2WVI17O61]10− retains its structural integrity and exhibits the strongest inhibition of AbPPO4 (Ki = 6.5 mM). The trilacunary POT [PV2WVI15O56]12− rearranges to the more stable monolacunary [α2-PV2WVI17O61]10− (~ 62%) accompanied by release of free phosphates and shows the weakest inhibition (Ki = 13.6 mM). The hexalacunary anion [H2PV2WVI12O48]12− undergoes time-dependent hydrolysis resulting in a mixture of [H2PV2WVI12O48]12−, [PV8WVI48O184]40−, [PV2WVI19O69(H2O)]14− and [α2-PV2WVI17O61]10− which together leads to comparable inhibitory activity (Ki = 7.5 mM) after 48 h. For the solutions of [α/β-PV2WVI18O62]6−, [α2-PV2WVI17O61]10− and [PV2WVI15O56]12− the inhibitory activity is correlated to the degree of their rearrangement to [α2-PV2WVI17O61]10−. The rearrangement of hexalacunary [H2PV2WVI12O48]12− into at least four POTs with a negligible amount of monolacunary anion interferes with the correlation of activity to the degree of their rearrangement to [α2-PV2WVI17O61]10−. The good inhibitory effect of the Wells–Dawson [α2-PV2WVI17O61]10− anion is explained by the low charge density of its protonated forms Hx[α2-PV2WVI17O61](10−x)− (x = 3 or 4) at pH 6.8.

Regulation of lipid homeostasis by the TBC protein dTBC1D22 via modulation of the small GTPase Rab40 to facilitate lipophagy.

The regulation of lipid homeostasis is not well understood. Using forward genetic screening, we demonstrate that the loss of dTBC1D22, an essential gene that encodes a Tre2-Bub2-Cdc16 (TBC) domain-containing protein, results in lipid droplet accumulation in multiple tissues. We observe that dTBC1D22 interacts with Rab40 and exhibits GTPase activating protein (GAP) activity. Overexpression of either the GTP- or GDP-binding-mimic form of Rab40 results in lipid droplet accumulation. We observe that Rab40 mutant flies are defective in lipid mobilization. The lipid depletion induced by overexpression of Brummer, a triglyceride lipase, is dependent on Rab40. Rab40 mutant flies exhibit decreased lipophagy and small size of autolysosomal structures, which may be due to the defective Golgi functions. Finally, we demonstrate that Rab40 physically interacts with Lamp1, and Rab40 is required for the distribution of Lamp1 during starvation. We propose that dTBC1D22 functions as a GAP for Rab40 to regulate lipophagy.

Suspension of Amorphous Calcium Phosphate Nanoparticles Impact Commitment of Human Adipose-Derived Stem Cells In Vitro.

Simple SummaryCalcium phosphate is an important component in natural bone. Bone defects caused by trauma or resection of tumors demand bone substitutes to close the defect. One viable option is to use a scaffold material seeded with stem cells. Stem cells can differentiate towards bone cells (osteoblasts), among other cell types. To trigger stem cells towards the osteoblast type of cell, particular supplementation of the culture medium is needed. This study tests whether calcium phosphate nanoparticles can induce a commitment towards the osteoblast type of cell. In addition, we test for other commitments, such as endothelial cell, chondrocyte, or adipocyte commitment. After 1 or 2 weeks, with either 5 or 50 µg/mL nanoparticles in the culture medium, gene expression is analyzed. We find a significant increase of two specific bone marker genes after two weeks in 50 µg/mL nanoparticles compared to 5 µg/mL for two out of three tested human donors of adipose-derived stem cells. Moreover, endothelial cell commitment is also induced. Hence, such nanoparticles have the potential to trigger osteogenic and endothelial cell commitment.Amorphous calcium phosphate (aCaP) nanoparticles may trigger the osteogenic commitment of adipose-derived stem cells (ASCs) in vitro. The ASCs of three human donors are investigated using basal culture medium DMEM to either 5 or 50 µg/mL aCaP nanoparticles suspension (control: no nanoparticles). After 7 or 14 days, stem cell marker genes, as well as endothelial, osteogenic, chondrogenic, and adipogenic genes, are analyzed by qPCR. Free calcium and phosphate ion concentrations are assessed in the cell culture supernatant. After one week and 5 µg/mL aCaP, downregulation of osteogenic markers ALP and Runx2 is found, and averaged across the three donors. Our results show that after two weeks, ALP is further downregulated, but Runx2 is upregulated. Endothelial cell marker genes, such as CD31 and CD34, are upregulated with 50 µg/mL aCaP and a 2-week exposure. Inter-donor variability is high: Two out of three donors show a significant upregulation of ALP and Runx2 at day 14 with 50 µg/mL aCaP compared to 5 µg/mL aCaP. Notably, all changes in stem cell commitment are obtained in the absence of an osteogenic medium. While the chemical composition of the culture medium and the saturation status towards calcium phosphate phases remain approximately the same for all conditions, gene expression of ASCs changes considerably. Hence, aCaP nanoparticles show the potential to trigger osteogenic and endothelial commitment in ASCs.

Abstract 2407: Serine and threonine phosphorylation marks proteins for degradation by ClpXP

Abstract The mitochondrial serine protease ClpXP regulates the integrity of the respiratory chain by degrading damaged and/or misfolded proteins. This protease is over-expressed in multiple malignancies and inhibiting or hyperactivating it kills malignant cells in vitro and in vivo. In Bacillus subtilis, the bacterial ClpXP homologue recognizes proteins tagged with phosphor-arginine for degradation. Yet, it is unknown how the mitochondrial ClpXP recognizes proteins for degradation. To determine how phosphorylated amino acids influence ClpXP-mediated protein degradation, we incubated recombinant ClpXP with its unnatural substrate FITC-casein and increasing concentrations of phospho-serine (pSer), phospho-threonine (pThr), phospho-arginine (pArg), or phosphor-tryrosine (pTry) in a cell-free assay and measured release of fluorogenic FITC. In a dose-dependent manner, pSer and pThr free amino acids inhibited casein cleavage by ClpXP while pTyr, pArg, and the dephosphorylated amino acids had no effect on ClpXP activity. Likewise, ApSA and ApTA peptides inhibited ClpXP enzyme activity, while the non-phosphorylated version (ASA and ATA) and no effect. Next, we tested whether the phosphorylation state of full length proteins would influence their degradation by ClpXP. Using gel-based cell-free assays, the phosphorylation enriched α-casein and β-casein were degraded by recombinant ClpXP. In contrast, the κ-casein with low phosphorylation level and dephosphorylated α-casein were not cleaved by ClpXP. In addition, we treated α-casein with lambda-phosphatases to dephosphorylate the protein and confirmed the release of free phosphate by the Malachite green phosphate assay. Phosphatase treated α-casein was resistant to ClpXP cleavage. As ClpXP is an AAA ATPase, we asked if pSer and pThr acted on the ATPase of the enzyme. pSer and pThr did not inhibit the ATPase activity of ClpX, as measured by the malachite green ATPase assay. We also measured the effect of pSer and pThr on the peptidase activity of ClpP alone without its regulatory subunit ClpX. Neither pSer or pThr inhibited ClpP peptidase activity. We investigated if pSer and pThr could bind to ClpX. Using thermal shift binding assays, we demonstrated that pSer and pThr but not pTyr and pArg bind ClpX and none of the phosphorylated amino acids bind ClpP. Finally, we characterized the total and phopho- mitochondrial proteome of T-REX HEK293 wild type and ClpP knockout cells by mass spectrometry. We identified 402 unique mitochondrial proteins and 38 phosphorylated mitochondrial proteins in wild type cells. 20 phosphorylated mitochondrial proteins increased in the ClpP knockout cells compared to wild type with a cut-off of 2 fold. In summary, we discovered that ClpX binds pSer and pThr and phosphorylation of these amino acids mark proteins for degradation by the ClpXP mitochondrial protease. This work highlights a new strategy to develop inhibitors of ClpXP for the treatment of cancer. Citation Format: Yue Feng, Yulia Jitkova, Aaron D. Schimmer. Serine and threonine phosphorylation marks proteins for degradation by ClpXP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2407.

Tubulin binding potentially clears up Bortezomib and Carfilzomib differential neurotoxic effect

Proteasome inhibitors (PIs) represent the gold standard in the treatment of multiple myeloma. Among PIs, Bortezomib (BTZ) is frequently used as first line therapy, but peripheral neuropathy (PN), occurring approximately in 50% of patients, impairs their life, representing a dose-limiting toxicity. Carfilzomib (CFZ), a second-generation PI, induces a significantly less severe PN. We investigated possible BTZ and CFZ off-targets able to explain their different neurotoxicity profiles. In order to identify the possible PIs off-targets we used the SPILLO-PBSS software that performs a structure-based in silico screening on a proteome-wide scale. Among the top-ranked off-targets of BTZ identified by SPILLO-PBSS we focused on tubulin which, by contrast, did not turn out to be an off-target of CFZ. We tested the hypothesis that the direct interaction between BTZ and microtubules would inhibit the tubulin alfa GTPase activity, thus reducing the microtubule catastrophe and consequently furthering the microtubules polymerization. This hypothesis was validated in a cell-free model, since BTZ (but not CFZ) reduces the concentration of the free phosphate released during GTP hydrolysis. Moreover, NMR binding studies clearly demonstrated that BTZ, unlike CFZ, is able to interact with both tubulin dimers and polymerized form. Our data suggest that different BTZ and CFZ neurotoxicity profiles are independent from their proteasome inhibition, as demonstrated in adult mice dorsal root ganglia primary sensory neurons, and, first, we demonstrate, in a cell free model, that BTZ is able to directly bind and perturb microtubules.

66 Strategies to Improve Phosphorus Utilization in Growing Pigs: Depletion-repletion Protocols

Abstract To optimize the use of dietary P by pigs, 5 feeding strategies were studied in a 3-phase feeding trial on 240 pigs (initial bodyweight (BW) of 31 kg): 1) C-C-C providing 100% of digestible phosphorus (Pdig, 4.3 g/kg STTD) and calcium (Ca, 9.7 g/kg) requirement to maximize bone mineralization, 2) L-L-L 60% of the Pdig and Ca requirements of C-C-C, 3) Phyt-Phyt-Phyt (phosphate-free, with phytase, 750, 686, 390 FTU/kg), providing 60% of Pdig and Ca requirements in phase 1, then 100%, 4) and 5) C in phases 1 and 3, and 60% of the need for Pdig in phase 2, associated with 65% of the requirements for Ca (N) or 80% (H), namely C-N-C and C-H-C. The BW and bone mineral content (BMC) were measured at the beginning and end of each phase. The BMC gain (gBMC), average daily gain (ADG) and average daily feed intake (ADFI) were calculated by phase. In phase 1, ADG was lower in the Phyt group than the C group (1.05 vs 1.10 kg/d, P < 0.01) and the BMC of group C and gBMC were higher than those of the Phyt and B groups (P < 0.05). In phase 2, C-C and Phyt-Phyt groups had similar BMC due to higher gBMC in the Phyt-Phyt (27.1 vs 18.4 g/d, P < 0.01). At the end of phases 2 and 3, C-C-C, C-N-C and C-H-C groups had similar BMC. The Phyt and B groups showed an increased phosphorus-use efficiency during phases 1 and 2 (+20% vs C). Phosphorus retention was also higher in the C-N-C and C-H-C groups, during the depletion in phase 2 (+24% vs C, P< 0.05). These results showed the potential of a depletion-repletion strategy including free phosphate diet to reduce phosphorus intake and excretion without affecting final growth performance and bone mineralization because of increased minerals utilization efficacies.

Cycling of reduced phosphorus compounds in soil and potential impacts of climate change

AbstractSoil phosphorus (P) remains an ever‐increasing topic of importance, notably for its key role as a nutrient for driving food production but with parallel concerns over damaging water quality, all against a backdrop of uncertainty of long‐term rock phosphate supplies. Soil is a key interface that holds P and regulates its onward flow to plants or leakage to waters. Often overlooked are a ubiquitous group of P compounds that exist in alternative oxidation states to that of phosphate (+5). Redox cycling, and the behaviour that chemically reduced P compounds exhibit in soils, introduces alternative routes of cycling P that may become more important as the soil system itself alters, especially due to the external pressures of climate change, bringing about critical dynamics in rainfall and runoff and also wetting and drying. All of these factors are known to affect soil redox potential and consequently the oxidation state of soil P. This review considers the chemically reduced species in the P cycle, exploring their sources and sinks, while considering their importance within the primary global biogeochemical cycling of P and how this may be impacted by climate change in the temperate climate of the northern hemisphere.Highlights This paper addresses how climate change will affect soil phosphorus cycling. This review is novel as it considers the reduced phosphorus forms when discussing P transfer in soils. Climate change is likely to increase prevalence of reduced P and free phosphate in northern hemisphere temperate soils. Phosphorus cycling relies partly on redox P processes. Their importance will increase as climate alters soils.

Process Simulation of the Influence of Phosphate Rock Impurities on the Production Index of Superphosphate

Through process simulation, the feasibility of the process and the influence of parameter changes on process indicators can be discussed, and guiding and optimizing the production process can be used. The impurities in phosphate rock mainly include components such as calcium carbonate, magnesium carbonate, iron trioxide, aluminum oxide and calcium fluoride, which presence can lead to changes in the production indicators of superphosphate. In this paper, the process simulation method is used to discuss the influence of the main impurity components in the phosphate rock on the production index of superphosphate. The results show that there is a linear relationship between the production index of superphosphate and the impurity coefficient. As the content of each impurity component increases, the effective P2O5 content and free acid P2O5 content of superphosphate products decrease, the free water content increases, the phosphate rock consumption quota decreases, and the sulfuric acid consumption quota increases. Among them, Al2O3 has the greatest impact on the product’s effective P2O5 content and free water content, CaF2 has the greatest impact on the product’s free acid P2O5 content and phosphate rock consumption quota, and MgCO3 has the greatest impact on the sulfuric acid consumption quota. The cumulative effect of various impurities on production indicators has a superimposing effect.

Mechanism of apatite formation on a poorly crystallized calcium phosphate in a simulated body fluid (SBF) at 37 °C

Calcium phosphate-based bioactive materials have recently attracted considerable attention. In particular, poorly crystalline apatites (PCA) are successfully used for bone repair and regeneration, enhancing the osteointegration and osteoconduction properties. Our study aims to better understand the mechanism of apatite formation on the poorly crystallized apatite powders. For this purpose, two PCA samples were synthesized in the same conditions while varying only the maturation time.The most noticeable difference between both samples is that the immature specimen (PCA2h) was richer in both water and HPO42− labile species than the mature specimen (PCA2m). Besides, it has a higher surface area and more negatively charged surface. Both PCA samples were soaked in a simulated body fluid (SBF) for different periods of time at 37 °C, leading to the neoformation of bone-like apatite layer on their surfaces due to their bioactivity. The surface of all samples was investigated using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy, zeta-potential measurements and BET analysis. FTIR spectroscopy, XRD, and TG-DTA were used to characterize bulk samples. Thermodynamic calculations of CaP precipitation were also performed. Experimental and theoretical data showed that the bone-like apatite formation mechanism on both samples undergoes by three stages. Only on the PCA2h, did a fast precipitation of positively Ca-rich amorphous phase (ACP) occur at a first time (prenucleation stage). It is converted into Ca-poor ACP by uptaking anions from surrounding media, to promote the formation of apatite nuclei during the second stage (nucleation stage). Then, nascent apatite crystals grew into bone like-apatite coating by poorly crystallized BCO3-apatite which is the most thermodynamically stable CaP phase in SBF (growing and maturation stage). While the bone like-apatite formation process on the mature PCA particles include similar events without Ca-rich ACP deposit. Thus, the formation of the Ca-poor ACP starts immediately at the beginning of soaking (at the 1st stage), followed by apatite nucleation (2nd stage), promoting the growth and maturation of BCO3-apatite crystals (3rd stage). Our results highlight the fact that in the waterlogged conditions of the hydrated shells surrounding the immature PCA nanocrystals, a high density of labile orthophosphate anions leads enriches the PCA-liquid solution interface in Ca2+ ions, momentarily stabilizing them into a positively charged amorphous complex likely to be strongly solvated. Then, this interface becomes more attractive for free orthophosphate anions, enhancing the bioactivity to improve osteointegration. The composition of the hydrated shells coating of the biomimetic apatite crystal in both labile species and hydration water seems to govern their bioactivity via surface charge potential and hydrophilic capacity. These data allow a better understanding of the bioactive behaviour of biomaterials involving biomimetic PCA phases for tissue engineering.

Cardiomyopathy mutations impact the actin-activated power stroke of human cardiac myosin

Cardiac muscle contraction is driven by the molecular motor myosin, which uses the energy from ATP hydrolysis to generate a power stroke when interacting with actin filaments, although it is unclear how this mechanism is impaired by mutations in myosin that can lead to heart failure. We have applied a fluorescence resonance energy transfer (FRET) strategy to investigate structural changes in the lever arm domain of human β-cardiac myosin subfragment 1 (M2β-S1). We exchanged the human ventricular regulatory light chain labeled at a single cysteine (V105C) with Alexa 488 onto M2β-S1, which served as a donor for Cy3ATP bound to the active site. We monitored the FRET signal during the actin-activated product release steps using transient kinetic measurements. We propose that the fast phase measured with our FRET probes represents the macroscopic rate constant associated with actin-activated rotation of the lever arm during the power stroke in M2β-S1. Our results demonstrated M2β-S1 has a slower actin-activated power stroke compared with fast skeletal muscle myosin and myosin V. Measurements at different temperatures comparing the rate constants of the actin-activated power stroke and phosphate release are consistent with a model in which the power stroke occurs before phosphate release and the two steps are tightly coupled. We suggest that the actin-activated power stroke is highly reversible but followed by a highly irreversible phosphate release step in the absence of load and free phosphate. We demonstrated that hypertrophic cardiomyopathy (R723G)- and dilated cardiomyopathy (F764L)-associated mutations both reduced actin activation of the power stroke in M2β-S1. We also demonstrate that both mutations alter in vitro actin gliding in the presence and absence of load. Thus, examining the structural kinetics of the power stroke in M2β-S1 has revealed critical mutation-associated defects in the myosin ATPase pathway, suggesting these measurements will be extremely important for establishing structure-based mechanisms of contractile dysfunction.

Green Synthesis of Iron Oxides and Phosphates via Thermal Treatment of Iron Polyphenols Synthesized by a Camellia sinensis Extract.

Iron oxide nanoparticles (FeONPs) prepared with plant extracts have been emerging as green and sustainable materials. FeONPs are usually amorphous due to the chelation of the tea polyphenols (TPs) to the iron, and the real nature of the iron compounds is not completely understood. The main goal of this study was to investigate the behavior of the green FeONPs synthesized from an Fe3+ salt and Cammelia sinensis (black tea) extract upon thermal treatment, in order to remove TPs and enable the formation of crystalline materials suitable for a thorough characterization and with the potential for diverse applications. The as-prepared FeONPs were assigned as mixed-valence Fe(III) oxyhydroxides and Fe(II)/Fe(III) ions bound to TPs. A detailed description of the phase transformation upon heating revealed the formation of the rare nano β-Fe2O3 phase at 400 °C, followed by a transformation to α-Fe2O3 as the temperature increased. Above 600 °C, the unprecedented formation of FePO4 and Fe3PO7 was observed, produced from the reaction of Fe2O3 and free phosphate ions present in the black tea leaves, Fe3PO7 being the major phase obtained at 900 °C. Finally, the catalytic potential of the FeONPs to treat the azo dye methyl orange through a heterogeneous Fenton-like system was investigated.

A Study on Consumer’s Preference Towards Green Products in Thoothukudi

Green marketing is also termed as environmental marketing or ecological marketing. According to the American Marketing Association, “marketing of products that are presumed to be environmentally safe is called as Green Marketing”. Green or environment friendly products like low power consuming (energy-efficient) electrical appliances, organic food, lead free paints, recyclable paper, and phosphate free detergents are increasingly sold in the Indian market owing to the recent awareness about green products among consumers. The study has looked into the factors influencing consumers to buy green products. The paper presents the results of a survey of 110 consumers in Thoothukudi. The study is based on primary data collected from the respondents. Additionally, the socio-economic profile of the respondents was examined. Percentage analysis, Garrett ranking technique, Likert’s scaling technique and factor analysis were used for analysing the data. In India, green marketers have diverse and fairly sizeable segments to cater to. Therefore, green marketers must find an opportunity to enhance the performance of green products through proper campaigns.

A novel derivatization strategy for profiling phosphate ester/anhydride metabolic network and application on glioma rats using HILIC-MS/MS

Phosphate esters and anhydrides have great significance in the field of biochemical research and medical therapy. The genetic materials (DNA or RNA), most of the coenzymes, many intermediary metabolites, such as nucleotides and glycosyl phosphates in vivo are phosphodiesters, phosphoric acid or phosphates, respectively. It is important to monitor endogenous active phosphate metabolites for investigating many biological processes or drug mechanism. However, the detection and determination of those free active phosphate metabolites are challenged due to their unstable and easily hydrolyzed property and relatively low sensitivity, especially diphosphates and triphosphates. In the current study, we successfully developed a strategy by 3-aminomethyl pyridine (AMPy) derivatization coupled with hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) for simultaneous determination of multiple types of phosphate metabolites with good stability in 48 h and 29 to 126-fold improvement of the limit of detection (LOD). Based on the diagnostic fragment ions of different types of AMPy-derivatized phosphate metabolites, characteristic MRM ion pairs were successfully performed for global profiling of the phosphate metabolites in phosphate ester/anhydride metabolic network, including nucleotide/deoxynucleotide mono/di/triphosphates, glycosyl mono/diphosphates, and other key phosphates, such as 5-phosphoribosyl-1-pyrophosphate (PRPP), SAICARP and FAICARP in HPF, HUVEC and PBMCs cells without standards. The developed strategy greatly expanded the coverage of applying a single derivatization reaction to analyze active phosphate metabolites. Finally, the established method was performed to investigate the phosphate esters and anhydrides based on a glioma rat model. For the first time, phosphate metabolites were comprehensively characterized based on phosphate ester and anhydride metabolic network, covering nucleotide metabolism, glycolysis and pentose phosphate pathways, etc. The results demonstrated that the applicability of the method could be extended to a wider range of active phosphate compounds and could facilitate to related applications in the future studies.

Significance and properties of the complex formation of phosphate and polyphosphate groups in particles present in living cells

• Phosphate groups in noncovalent interactions. • Complex formation of phosphorylated ligands. • Influence of pH on the effectiveness of binding the phosphate group. • The effect of polyamine excess on the mode of coordination of phosphates. Phosphorus, occurring mainly in the form of phosphate, is an essential element for the proper functioning of living systems. Phosphate and polyphosphate groups occur as inorganic phosphate (free phosphate anion in solution) and are present in biomolecules such as phosphorylated amino acids, nucleotides, and phytic acid. In solution, phosphates can exist in four different forms depending on pH, and they are involved in non-covalent interactions with positively charged species. This review summarizes the participation of phosphates of nucleotides, phosphorylated amino acids, and phytic acid in weak interactions with biogenic amines and in complexes with biometal ions not only in solution but also in solid state. The study of these processes can enable to understand many of the most important aspects of a cell’s life, thus explaining why, for example, abnormal phosphorylation leads to the development of diseases, and highlighting the role of phosphates in chemical interactions. In addition, the formation of one-, two-, and three-dimensional polynuclear metal-phosphonate assemblies by phosph(on)ate ligands has been described.