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Purification and characterization of a polyphosphate kinase from Arthrobacter atrocyaneus.

Polyphosphate kinase, an enzyme which incorporated the gamma-phosphate of ATP into long-chain polyphosphate molecules, was purified more than 700-fold from Arthrobacter atrocyaneus by ammonium sulphate fractionation, DEAE-cellulose column chromatography and Ssphadex G-200 gel filtration. The enzyme had a broad pH optimum at 6-0 to 7-0 and required Mn2+ or Mg2+, histone, and inorganic phosphate for activity. The Km for Mn-ATP was 0-53 mM, and for inorganic phosphate was 1-67 mM. Free ATP concentrations greater than 8 muM inhibited the enzyme. Free Mn2+ or Mg2+ concentrations greater than 2 mM or 6 mM, respectively, were also inhibitory. Activity was strongly inhibited by 4 mM-ADP, 1 mM-PP1 or 20 mM-NaF. The effect of ADP might have resulted from reversing the equilibrium of the kinase reaction. The activation by phosphate ions might indicate a role for the enzyme in regulating intracellular phosphate levels or maintaining a phosphorus reserve. The level of enzymic activity in the bacteria responded to changes in inorganic phosphate concentration in the medium. Basic proteins, such as protamine, could substitute for histone as activator. Proteins such as casein or bovine serum albunim would also substitute for histone but only in the absence of inorganic phosphate. The presence of a protein might be necessary to form a complex with the product, thus preventing reversal of the reaction in vitro. The reaction product was characterized, and found to be labile in hydroxylamine, base, and acid at 100 degrees C. It behaved as a long-chain-polyphosphate molecule on chromatography in an Ebel's solvent. The enzymic activity was therefore not that of a protein kinase.

Adenosine Triphosphate↗

Application of a fuzzy algorithm for pH control in a struvite crystallisation reactor.

A struvite crystallisation process is highly dependent on pH. To achieve a high phosphorus recovery as struvite it is important to have an accurate control of pH in the reactor. The high non-linear response of pH value makes manual pH control difficult. Therefore, a software based on fuzzy logic control (FLC) has been developed to maintain the pH at a set value in a stirred reactor to crystallise struvite. The FLC developed has been based on Larsen's inference. In order to confirm the improvement of the pH stability using FLC software, different experiments have been carried out with manual control of the pH value, and with the FLC software. It has been demonstrated that using FLC software allows a precise control of pH with high stability, optimises the process, and minimises the operator intervention.

Algorithms↗

Broad-spectrum determination of pesticides in groundwater by gas chromatography with electron capture detection, nitrogen-phosphorus detection, and tandem mass spectrometry.

Gas chromatography with electron capture detector (ECD), nitrogen-phosphorus detector (NPD), and tandem mass spectrometry (MS/MS) was used to identify 36 pesticides, widely used to control various pest and diseases in vegetables, in water after a preconcentration step on C18 cartridges. The recoveries obtained ranged from 70 to 135% at a fortification level of 100 ng/L with relative standard deviations of <36.2%. The limits of detection and quantitation were < or =48 and < or =160 ng/L, respectively. Important advantages of MS/MS over ECD and NPD in the determination of pesticides are also presented. The proposed analytical methodology was applied to the determination of pesticides in groundwater samples from an agricultural area, the Campo de Dalías (Almería, Spain). The most frequently encountered pesticides were endosulfan sulfate and metalaxyl, whereas the pesticide found at the highest concentration was fenamiphos.

Alanine↗

Neutral and zwitterionic low-coordinate titanium complexes bearing the terminal phosphinidene functionality. Structural, spectroscopic, theoretical, and catalytic studies addressing the Ti-P multiple bond.

Alpha-hydrogen abstraction and alpha-hydrogen migration reactions yield novel titanium(IV) complexes bearing terminal phosphinidene ligands. Via an alpha-H migration reaction, the phosphinidene ((tBu)nacnac)Ti=P[Trip](CH(2)(tBu) ((tBu)nacnac(-) = [Ar]NC((t)Bu)CHC((t)Bu)N[Ar], Ar = 2,6-(CHMe2)(2C6H3, Trip = 2,4,6-(i)Pr3C6H2) was prepared by the addition of the primary phosphide LiPH[Trip] to the nucleophilic alkylidene triflato complex ((tBu)nacnac)Ti=CH(t)Bu(OTf), while alpha-H abstraction was promoted by the addition of LiPH[Trip] to the dimethyl triflato precursor ((tBu)nacnac)Ti(CH)(2)(OTf) to afford ((tBu)nacnac)Ti=P[Trip](CH3). Treatment of ((tBu)nacnac)Ti=P[Trip](CH3) with B(C6F5)(3) induces methide abstraction concurrent with formation of the first titanium(IV) phosphinidene zwitterion complex ((tBu)nacnac)Ti=P[Trip]{CH3B(C6F5)(3)}. Complex ((tBu)nacnac)Ti=P[Trip]{CH3B(C6F5)(3)} [2 + 2] cycloadds readily PhCCPh to afford the phosphametallacyclobutene [((tBu)nacnac)Ti(P[Trip]PhCCPh)][CH3B(C6F5)(3)]. These titanium(IV) phosphinidene complexes possess the shortest Ti=P bonds reported, have linear phosphinidene groups, and reveal significantly upfielded solution 31P NMR spectroscopic resonances for the phosphinidene phosphorus. Solid state 31P NMR spectroscopic data also corroborate with all three complexes possessing considerably shielded chemical shifts for the linear and terminal phosphinidene functionality. In addition, high-level DFT studies on the phosphinidenes suggest the terminal phosphinidene linkage to be stabilized via a pseudo Ti[triple bond]P bond. Linearity about the Ti-P-C(ipso) linkage is highly dependent on the sterically encumbering substituents protecting the phosphinidene. Complex ((tBu)nacnac)Ti=P[Trip]{CH3B(C6F5))(3)} can catalyze the hydrophosphination of PhCCPh with H(2)PPh to produce the secondary vinylphosphine HP[Ph]PhC=CHPh. In addition, we demonstrate that this zwitterion is a powerful phospha-Staudinger reagent and can therefore act as a carboamination precatalyst of diphenylacetylene with aldimines.

Acetylene↗

Comparison of phosphate metabolites of the ocular humors.

Ocular humors (aqueous humor and vitreous body) were obtained from porcine eyes. Perchloric acid extracts were prepared from aqueous and vitreous aspirates, and phosphorus-31 nuclear magnetic resonance spectroscopy 31P-NMR performed. Resonance signals from four high-energy phosphate groups (phosphocreatine, adenosine tri- and diphosphate and the dinucleotides) and nine low-energy phosphate groups [dihydroxyacetone phosphate, hexose-6-phosphate, alpha-glycerophosphate, fructose-1,6-diphosphate, ethanolamine phosphate, choline phosphate, inorganic orthophosphate (Pi), glycerol-3-phosphorylethanolamine and glycerol-3-phosphorylcholine] were present in the aqueous humor and/or vitreous body. Vitreous body phosphates significantly elevated relative to that of the aqueous humor were: DHAP, Hex 6-P, alpha-GP, Fru 1,6-diP, CP, GPE, PCr, ATP, ADP, and the dinucleotides; only Pi was significantly lower. Six metabolic indices (monoesters, diesters, monoesters/diesters, monoesters/Pi, ATP/Pi, energy modulus) were determined; all vitreous body indices were significantly higher than those of the aqueous humor. In particular, the energy modulus, a measure of overall metabolic energy status, was higher in the vitreous body (0.121 +/- 0.047) than in the aqueous humor (0.05 +/- 0.021).

Animals↗

Investigation of compound-independent calibration and partial molecular formula determination by gas chromatography-atomic-emission detection for characterisation of organophosphorus and organosulfur agents related to the chemical weapons convention.

Atomic-emission detection (AED) is a technique particularly-well suited to screening complex samples for multiple compounds containing heteroatoms such as phosphorus, sulfur, or nitrogen, which are especially relevant in verification of chemical disarmament. Among other GC detectors, AED has unique characteristics such as compound-independent calibration and possible raw-formula determination. Because contradictory results have been reported on these points, we set up a study with the objectives not only of applying these techniques to chemical weapons convention-related chemicals but of determining under which conditions they would yield satisfactory results. The extensive data collected in this study are evidence that the response of the detector, particularly for the phosphorus line, is very dependent on the molecular mass and concentration of the chemicals analysed whereas molecular structure seems to have less effect on the AED signal. Most interestingly, compound-independent calibration and subsequent partial molecular formula determination usually seem satisfactory when the reference compounds used to calibrate the system have GC retention times and molecular masses close to those of the unknown analytes (whose molecular mass may be determined by GC-CI-MS). We therefore suggest the use of a reference set of compounds covering a large chromatographic window, which enables the selection, within this set, of the most appropriate reference compound for calibration and for determination of the raw formula of an unknown analyte. For optimal performance, the use of a new discharge tube is also recommended.

Algorithms↗

Sodium ion transport in rat hearts during cold ischemic storage: 23Na and 31P NMR study.

The success of heart transplantation is limited by the negative correlation between the length of the cold ischemic storage period and the quality of functional recovery. We use 23Na, 31P NMR spectroscopy, and hemodynamic parameters to describe temperature-dependent changes in sodium influx and the concentration of phosphorus high-energy compounds during different storage periods. Perfusion with Krebs-Henseleit solutions containing Dy(TTHA)3- permitted discrimination of intra- and extracellular sodium during cold ischemic storage. The 23Na NMR visibilities under the acquisition and processing parameters used in our experiments were 40 +/- 4% for the intracellular compartment and 97 +/- 11% for the extracellular compartment. At 4 degrees C, the intracellular Na+ accumulation exceeded that observed at 15 and 22 degrees C. The ATP and PCr depletion rates were much lower at 4 degrees C and the left ventricular contractility was higher after longer periods of storage, as the storage temperature decreased. The intracellular Na+ concentration cannot serve as a marker for the postischemic recovery probability. The relative activity of the Na/K ATPase pumps is not correlated with the preservation success. However, intracellular sodium ion accumulation is a major factor in the time lag of the reperfusion recovery.

Animals↗

Nutrient and organic carbon trends and patterns in the upper Rio Grande, 1975-1999.

Nutrient patterns and trends were analyzed using USGS water quality data collected from 1975 to 1999 along the uppermost 600 km of the Rio Grande in Colorado and New Mexico. Data on discharge, pH, organic carbon (total), N-NH(4+)+organic N (total), NH4+ (dissolved), N-NO(2-)+N-NO3- (dissolved), phosphorus (total), and P-orthophosphate (dissolved) came from six USGS stations--Lobatos, Taos Junction, Otowi, San Felipe, Isleta and Bernardo--ranging from the Colorado-New Mexico border to about 80 km below Albuquerque, NM. Kendall's S and Seasonal Kendall's S' were used to measure trend, and ANOVA and Tukey's multiple comparison test were used to analyze spatial differences between stations. Temporal trend analyses show widespread decreases in N and P concentrations at most stations, likely due to improvements in sewage treatment and dilution from increasing discharge. N-NO(2-)+N-NO3- (dissolved) and total nitrate load increases at Isleta and Bernardo, likely due to improved nitrification in sewage treatment and to increasing human population. Spatial analyses show large increases for most parameters at Isleta. All parameters show decreases again at Bernardo, about 50 km downstream from Isleta, except for N-NO(2-)+N-NO3- (dissolved), which continues to increase. Urbanization in the Albuquerque area significantly impacts downstream river nutrient levels.

Colorado↗

Determination of very-long-chain fatty acids in serum by gas chromatography-nitrogen-phosphorus detection following cyanomethylation.

A sensitive method for very-long-chain fatty acid analysis was developed by gas chromatography-nitrogen-phosphorus detection by using cyanomethyl derivatization. Bromoacetonitrile as alkylating reagent was used to improve nitrogen phosphorus detection detectability of compounds containing non-nitrogen. The carboxyl group of very-long-chain fatty acid was alkylated to cyanomethyl esters. Reaction conditions were 40 min at 60 degrees C under potassium carbonate base. Heptacosanoic acid was used as an internal standard and hexane was used as a solvent of extraction. The extraction yield was 82.8% or more, relative standard deviation of the precision test was 8.3% or more and the result of linearity test showed a good correlation coefficient of r2=0.999 in the range of 0.1-50 microg/ml. The quantification limits were 10 ng/ml when 0.5 ml of serum was used. The present method proved simple, rapid, inexpensive and resistant to contaminants. When it was applied to serum samples taken from patients with X-linked adrenoleukodystrophy which is a hereditary X-linked disorder characterized by progressive demyelination and adrenal insufficiency during childhood, relative increase of the concentration of hexacosanoic acid and the concentration ratios of hexacosanoic, lignoceric to behenic acid was observed in comparison with control samples.

Adrenoleukodystrophy↗

Major intermediates in organophosphate synthesis (PCl3, POCl3, PSCl3, and their diethyl esters) are anticholinesterase agents directly or on activation.

Three phosphotrichlorides [phosphorus trichloride (PCl(3)), phosphorus oxychloride (POCl(3)), and thiophosphoryl chloride (PSCl(3))] with an annual U.S. production of >500,000,000 pounds and their diethyl esters are intermediates in the production of organophosphorus pesticides, plastics, flame retardants, and hydraulic fluids. They are classified as highly toxic to mammals based on acute oral and inhalation data with rats. This study considers their mechanisms of toxicity. PCl(3) and POCl(3) inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) from several species with in vitro IC(50) values of 5-36 and 88-1200 microM, respectively; PSCl(3) is a less potent inhibitor. These phosphotrichlorides have high vapor toxicity to houseflies with in vivo inhibition of brain AChE activity correlating with mortality. PCl(3) and POCl(3) produce cholinergic poisoning signs on ip administration to mice, and all three phosphotrichlorides give marked in vivo inhibition of serum BChE but not brain AChE activity. PCl(3) is a direct acting AChE inhibitor. Our earlier proposed activation of POCl(3) is confirmed here by preparing pure Cl(2)P(O)OH and its potassium and dicyclohexylamine salts that reproduce the action of POCl(3) as in vitro AChE inhibitors and toxicants in mice. PSCl(3) on hydrolysis yields Cl(2)P(O)SH [which oxidizes with peracid to Cl(2)P(O)SOH] as the proposed activation product. Vapors of (EtO)(2)PCl, (EtO)(2)P(O)Cl, and (EtO)(2)P(S)Cl are lethal to houseflies as in vivo AChE inhibitors, the first two acting directly and the last one on oxidative activation to (EtO)(2)P(O)Cl (possibly by P450) or (EtO)(2)P(O)SCl (a phosphorylating agent in a peracid oxidation system). Thus PCl(3), (EtO)(2)PCl, and (EtO)(2)P(O)Cl act directly as AChE inhibitors whereas POCl(3) and PSCl(3) undergo hydrolytic activation and (EtO)(2)P(S)Cl undergoes oxidative activation. In contrast, the toxicity to mice of phosphofluorides [FP(O)Cl(2), F(Cl)P(O)OH, and F(2)P(O)OH; studied as model compounds for comparison] may be due to liberating fluoride ion.

Acetylcholinesterase↗

In situ stabilization of soil lead using phosphorus and manganese oxide: influence of plant growth.

In situ stabilization of Pb contaminated soils can be accomplished by adding P and Mn(IV) oxide. However, the long-term efficacy of in situ stabilization under continual P removal through plant growth is unknown. Moreover, the effects these treatments have on phytoavailability of other metals (Cd and Zn) commonly associated with Pb in soil are not well understood. Greenhouse experiments using sudax [Sorghum vulgare (L.) Moench] and Swiss chard [Beta vulgaris (L.) Koch] were carried out to evaluate the effects of plant growth on soil Pb bioavailability to humans after addition of P and other amendments, and the effects of these treatments on Pb, Cd, and Zn phytoavailability in three metal-contaminated soils. Eight treatments were used: zero P; 2500 mg of P as triple superphosphate (TSP); 5000 mg of P as TSP or phosphate rock (PR); 5000 mg of Mn oxide/kg; and combinations of Mn oxide and P as TSP or PR. The addition of P and/or Mn oxide significantly reduced bioavailable Pb, as measured by the physiologically based extraction test (PBET), in soils compared with the control even after extensive cropping. The PBET data also suggested that removal of P from soluble P sources by plants could negate the beneficial effects of P on bioavailable Pb, unless sufficient soluble P was added or soluble P was combined with Mn oxide. In general, Ph, Cd, and Zn concentrations in shoot tissues of sudax and Swiss chard were reduced significantly by TSP and did not change with the addition of PR. The combination of PR and Mn oxide significantly reduced Pb concentrations in plants compared with the control.

Beta vulgaris↗

Treatment of contaminated soil with phosphorus and manganese oxide reduces lead absorption by Sprague-Dawley rats.

This study was conducted to determine the extent of Pb absorption into young rats (Rattus norvegicus var. Sprague-Dawley) fed untreated Pb-contaminated soil or Pb-contaminated soil treated with two different sources of P and P + Mn oxide. Data were compared from an in vitro, physiologically based extraction test (PBET) with the animal data to support the validity of the in vitro test to assess bioavailable Pb from a treated Pb-contaminated soil. Soil with a total Pb concentration of 2290 mg kg(-1) was used. Rats were fed 19 different test diets for 21 consecutive days. The test diets represented 95 g AIN93G rat meal kg(-1) diet with varying proportions of silica sand or soil to provide low, medium, or high doses of Pb from either Pb acetate, treated, or untreated soil. Blood, liver, kidney, and bone Pb concentrations were examined. For all four tissues, Pb concentrations for the Pb acetate groups were significantly higher than concentrations for all the soil groups. In general, either triple superphosphate (TSP) or phosphate rock (PR) treatments resulted in significant reductions in tissue Pb concentrations compared with untreated soil. Blood and kidney Pb concentrations for the PR + Mn oxide group were significantly lower than those of the PR group at the low and high doses. Relative bioavailability of Pb, as measured in all tissues, was significantly reduced when comparing untreated with amended soil. Correlation between the in vitro and in vivo tests, based on bone and liver tissue, showed that the in vitro test is successful at predicting Pb bioavailability.

Absorption↗

Extreme spatial variability and unprecedented methylmercury concentrations within a constructed wetland.

We began monitoring concentrations of both total mercury (THg) and methylmercury (MeHg) in surface water at Stormwater Treatment Area-2 (STA) on July 20, 2000. This 2602 hectare STA was constructed with three independent marshes to remove phosphorus from agricultural runoff and reduce eutrophication in the northern Everglades. However, there was concern that in doing so, STA-2 might inadvertently worsen the existing mercury problem in the Everglades. Accordingly, operating permits stipulated that flow-through operation of these treatment cells could not begin until concentrations of THg and MeHg in the interior marsh were not significantly greater than corresponding concentrations in the supply canal. Cells 2 and 3 quickly met the start-up criteria in the fall of 2000. In contrast, Cell 1 exhibited anomalously high MeHg concentrations in the fall of 2000 and 2001, and the summer of 2002. During the last such event, water-column concentrations in Cell 1 reached 32 ng THg/L and an unprecedented 20 ng MeHg/L. Tissue Hg in resident fishes reached levels as high as 430 ng/g in mosquitofish, Gambusia holbrooki, 930 ng/g in sunfish, Lepomis spp., and 2000 ng/g in largemouth bass, Micropterus salmoides. Guided by results from the monitoring program, flow rate and water depth were managed as a means to alter sulfur biogeochemistry and, thereby, reduce in situ mercury methylation. This adaptive management strategy likely played a role in the decline in water-column concentrations of THg and MeHg in Cell 1 by late 2002 and the subsequent declines in tissue Hg levels in resident fishes. Cell 1 finally met formal start-up criteria on November 26, 2002.

Animals↗

Water-soluble and solid-state speciation of phosphorus in stabilized sewage sludge.

Three chemicals, ferrous sulfate (Fe-sul), calcium oxide (CaO), and aluminum sulfate (alum), were used to stabilize phosphorus (P) in fresh, anaerobically digested sewage sludge (FSS). The chemically stabilized sludge materials and biosolids compost (BSC) were compared with the FSS with respect to water-soluble phosphorus (WSP) content in its inorganic (WSP(i)) and organic (WSP(o)) forms as well as water-soluble organic carbon (DOC). Solid-state P speciation was further probed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray elemental spectrometry (EDXS). Water-soluble P was effectively controlled by a wide range of Fe-sul or CaO additions to the sludge (Ca to P ratio = 3.47-17.72, Fe to P ratio = 1.01-16.53), but by only a narrow range (Al to P ratio = 1.04-2.87) of alum addition. The WSP content in the BSC was also depressed, but to a lesser extent. The pH in the treated sludge ranged from 3.0 to 12.5 and served as a key factor to control P chemistry. No correlation was observed between DOC and WSP(o). No crystallized Ca-P minerals were detected in the CaO-stabilized sludge, but brushite crystallization seemed to be obtained by low addition of Fe-sul and alum. Variscite and strengite crystallization was obtained following high addition of Fe-sul or alum, as detected by XRD and SEM-EDXS. Adsorption of P by newly formed Fe-hydroxide seems to play an important role in the Fe-sul-stabilized sludge. We concluded that administration of the tested chemicals at the proper rate can effectively reduce the hazard of P release and leaching from sludge.

Adsorption↗

31P NMR probes of chemical dynamics: paramagnetic relaxation enhancement of the (1)H and (31)P NMR resonances of methyl phosphite and methylethyl phosphate anions by selected metal complexes.

Methyl phosphite ((CH(3)O)P(H)(O)(2)(-); MeOPH) and methylethyl phosphate ((CH(3)O)P(OCH(2)CH(3))(O)(2)(-); MEP) are two members of a class of anionic ligands whose (31)P T(2) relaxation rates are remarkably sensitive to paramagnetic metal ions. The temperature dependence of the (31)P NMR line broadenings caused by the Mn(H(2)O)(6)(2+) ion and a water-soluble manganese(III) porphyrin (Mn(III)TMPyP(5+)) indicates that the extent of paramagnetic relaxation enhancement is a measure of the rate at which the anionic probes come into physical contact with the paramagnetic center (i.e., enter the inner coordination shell); that is, piDeltanu(par) = k(assn)[M], where Deltanu(par) is the difference between the line widths of the resonance in paramagnetic and diamagnetic solutions, and k(assn) is the second-order rate constant for association of the phosphorus ligand with the metal, M. Comparison of the (31)P T(1) and T(2) relaxation enhancements shows that rapid T(2) relaxation by the metal ion is caused by scalar interaction with the electronic spin. Relaxation of the phosphorus-bound proton of MeOPH ((1)H-P) by Mn(III)TMPyP(5+) displayed intermediate exchange kinetics over much of the observable temperature range. The field strength dependence of (1)H-P T(2) enhancement and the independence of the (31)P T(2) support these assertions. As in the case of the (31)P T(2), the (1)H-P T(2) relaxation enhancement results from scalar interaction with the electronic spin. The scalar coupling interpretation of the NMR data is supported by a pulsed EPR study of the interactions of Mn(H(2)O)(6)(2+) with the P-deuterated analogue of methyl phosphite, CH(3)OP((2)H)(O)(2)(-). The electron to (31)P and (2)H nuclear scalar coupling constants were found to be 4.6 and 0.10 MHz, respectively. In contrast, the effects of paramagnetic ions on the methoxy and ethoxy (1)H resonances of MeOPH and MEP are weak, and the evidence suggests that relaxation of these nuclei occurs by a dipolar mechanism. The wide variation in the relaxation sensitivities of the (1)H and (31)P nuclei of MeOPH and MEP permits us to study how differences in the strengths of the interactions between an observed nucleus and a paramagnetic center affect NMR T(2) relaxations. We propose that these anion ligand probes may be used to study ligand-exchange reactivities of manganese complexes without requiring variable temperature studies. The (31)P T(2) is determined by chemical association kinetics when the following condition is met: (T(2M,P)/T(2M,H))(Deltanu(P)/Deltanu(HP) - 1) < 0.2 where T(2M,P) and T(2M,H) are the transverse relaxation times of the (31)P and (1)H nuclei when the probe is bound to the metal, and Deltanu(P) and Deltanu(HP) are the paramagnetic line broadenings of the (31)P and (1)H-P nuclei, respectively. We assert that the ratio T(2M,P)/T(2M,H) can be estimated for a general metal complex using the results of EPR and NMR experiments.

Algorithms↗