Organic Phosphorus Compounds Research Articles

Diversity of Beta-Propeller Phytase Genes in the Intestinal Contents of Grass Carp Provides Insight into the Release of Major Phosphorus from Phytate in Nature

Phytate is the most abundant organic phosphorus compound in nature, and microbial mineralization of phytate by phytase is a key process for phosphorus recycling in the biosphere. In the present study, beta-propeller phytase (BPP) gene fragments were readily amplified from the intestinal contents of grass carp (Ctenopharyngodon idellus) directly or from phytate-degrading isolates from the same source, confirming the widespread occurrence of BPP in aquatic communities. The amounts of sequences collected using these two methods differed (88 distinct genes versus 10 isolates), but the sequences showed the same general topology based on phylogenetic analysis. All of the sequences fell in five clusters and were distinct from those of Anabaena, Gloeobacter, Streptomyces, Flavobacterium, Prosthecochloris, and Desulfuromonas, which have never been found in the grass carp intestine. Analysis of the microbial diversity by denaturing gradient gel electrophoresis demonstrated that unculturable bacteria were dominant bacteria in the grass carp intestine and thus the predominant phytate-degrading organisms. The predominant cultured species corresponding to the phytate-degrading isolates, Pseudomonas, Bacillus and Shewanella species, might be the main source of known BPPs. A phytase from Brevundimonas was first obtained from cultured species. Combining our results with Lim et al.'s inference that phytate-mineralizing bacteria are widely distributed and highly diverse in nature (B. L. Lim, P. Yeung, C. Cheng, and J. E. Hill, ISME J. 1:321-330, 2007), we concluded that BPP is the major phytate-degrading enzyme in nature, that most of this enzyme might originate from unculturable bacteria, and that the distribution of BPP may be related to the type of niche. To our knowledge, this is the first study to experimentally estimate BPP diversity in situ.

Anoxic–aerobic treatment of the liquid fraction of cattle manure

Cattle manure from a dairy farm was treated in order to reduce its pollution potential. The manure came from a farm with 120 cows kept in stables in a free stall barn. As pretreatment, the manure is usually filtered on the farm using a screw press separator with a 0.5 mm mesh. Approximately 70% of the total filtered volume passes through the screen, thus constituting the liquid fraction. This fraction, with a composition of around 64,500 mg COD/l, 5770 mg total-N/l and 800 mg total-P/l, was subjected to centrifugation followed by a two-step biological treatment (anoxic-aerobic) to reduce organic matter (COD), nitrogen and phosphorus compounds. Centrifugation led to the following removal efficiencies: 35% total solids, 60% COD, 75% total phosphorus and 20% total nitrogen (mainly organic nitrogen). With the subsequent anoxic-aerobic treatment, average removal efficiencies of 85% for COD, 90% for total phosphorus and 75% for total nitrogen were achieved.

Screening for Organic Phosphorus Compounds in Aquatic Sediments by Liquid Chromatography Coupled to ICP-AES and ESI-MS/MS

The structures of organic phosphorous (P) compounds in aquatic sediments are to a large extent unknown although these compounds are considered to play an important role in regulating lake trophic status. To enhance identification of these compounds, a liquid chromatography (LC) method for their separation was developed. The stationary phase was porous graphitic carbon (PGC), and the mobile phases used in the gradient elution were compatible with both inductive coupled plasma atomic emission spectroscopy (ICP-AES) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). With LC-ICP-AES, eight different P containing peaks could be observed in the P chromatogram indicating that at least eight different P compounds were separated. With the setup of an information dependent acquisition (IDA) with ESI-MS/MS, the mass over charge ( m/ z) of compounds containing a phosphate group (H 2PO 3 (-), m/ z 97) could be measured and further fragmentation experiments gave additional information on the structure of almost 40 separated P compounds, several were verified to be nucleotides. ICP-AES was very suitable in the development of the LC method and allowed screening and quantification of P compounds. The presented LC-ESI-MS/MS technique was able to identify several sediment organic P compounds.

MARINE METHANE MYSTERY EXPLAINED

AEROBIC BREAKDOWN of methylphosphonate into methane by marine microbes may account for high levels of methane found in ocean surface waters, according to a new report in Nature Geoscience ( 2008, 1 , 473). Methane is a potent greenhouse gas, and oceanic contributions to the global methane budget are not well understood. “Why methane concentrations in the oxygen-rich surface waters of most of the world’s oceans are so high has remained a puzzle, as methane production is thought to occur in strictly anaerobic environments,” writes Ellery D. Ingall, an associate professor at Georgia Tech who studies marine phosphorus cycling, in a commentary accompanying the report. Living organisms need phosphorus to grow. Phosphonates abound in the ocean but make up only a small percentage of total marine phosphorus nutrients. Although most microorganisms prefer to munch on more common organic phosphorus compounds, it’s likely that they adapt to phosphonates in nutrientpoor regions of the ocean and generate methane, Ingall ...

Rate of phosphoantimonylmolybdenum blue complex formation in acidic persulfate digested sample matrix for total dissolved phosphorus determination: Importance of post-digestion pH adjustment

Acidic persulfate oxidation is one of the most common procedures used to digest dissolved organic phosphorus compounds in water samples for total dissolved phosphorus determination. It has been reported that the rates of phosphoantimonylmolybdenum blue complex formation were significantly reduced in the digested sample matrix. This study revealed that the intermediate products of persulfate oxidation, not the slight change in pH, cause the slowdown of color formation. This effect can be remedied by adjusting digested samples pH to a near neural to decompose the intermediate products. No disturbing effects of chlorine on the phosphoantimonylmolybdenum blue formation in seawater were observed. It is noted that the modification of mixed reagent recipe cannot provide near neutral pH for the decomposition of the intermediate products of persulfate oxidation. This study provides experimental evidence not only to support the recommendation made in APHA standard methods that the pH of the digested sample must be adjusted to within a narrow range of sample, but also to improve the understanding of role of residue from persulfate decomposition on the subsequent phosphoantimonylmolybdenum blue formation.

Inhibition of Thermal Oxidation Destruction of PBT/HDPE Blends by Organic Compounds of Five-valent Phosphorus

Abstract Polybutylene terephthalate (PBT) and highy density polyethylene (HDPE) were blended and stabilized with four different stabilizers obtained from the organic derivatives of five-valent phosphorus. These stabilizers were cyclohexylphosphonic acid, its metallic salts of cyclohexyl phosponates of bivalent nickel, bivalent iron and trivalent iron. The stabilization improved the thermal stability of the PBT/HDPE blends and increased their mass loss temperature. The blend melts were thermally aged inside a viscometer barrel and the Melt flow Index (MFIs) was measured. All stabilizers increased the melt stability of the blends when used in low rates (< 0.2 % in mass). At higher stabilizer rates, some stabilizers further enhanced the thermal stability, while others decreased it. A melt parameter was introduced to determine the melt stability of the PBT/HDPE blends during extrusion. The best stabilization was obtained with cyclohexylphosphonic acid based on the metallic salts of bivalent nickel. The mechanisms that lead to the inhibition of thermal destruction of the blends were explained in terms of the stabilizers.

Resource partitioning for soil phosphorus: a hypothesis

Summary Organic phosphorus is abundant in soil and its turnover can supply a considerable fraction of the phosphorus taken up by natural vegetation. Despite this, the ecological significance of organic phosphorus remains poorly understood, which is remarkable given the biological importance of phosphorus in terrestrial environments. Of particular interest is the possibility that coexisting plant species partition soil organic phosphorus to reduce competition. This seems likely given the large number of biologically available phosphorus compounds that occur in soil and the variety of mechanisms by which plants can utilize them. Here I propose a conceptual model of resource partitioning for soil phosphorus. The model describes a hypothetical example of four coexisting plant species that differ in their ability to access soil organic phosphorus compounds, which are grouped to form a gradient of biological availability based on the processes involved in their utilization by plants. Synthesis: Resource partitioning for soil phosphorus could provide an additional mechanism to explain the coexistence and distribution of plant species. It is likely to occur widely in terrestrial environments, but should have greatest ecological significance wherever productivity is limited by the availability of soil phosphorus. This includes freshwater wetlands, super‐humid temperate regions and ecosystems developed on strongly‐weathered soils that cover vast areas of ancient landscapes in Africa, Australia and South America.

Isolation and characterization of a novel phytase gene (Sphy1) from soybean (Glycine max (L.) Merr.)

A novel phytase gene Sphy1 was isolated based on screening a cDNA library which was constructed from germinated soybean (Glycine max (L.) Merr. cv. Kefeng 6) cotyledon. The full-length cDNA of Sphy1 was 1644 bp predicated to encode 547 amino acids including an N terminal signal peptide of 27 amino acids. Phylogenetic analysis indicated that Sphy1 had high similarities with the phytase genes from Medicago truncatula and rice, and acid phosphatase genes from M. truncatula and Arabidopsis. Prokaryotic expression of Sphy1 in Escherichia coli BL21 (DE3) showed that the induced protein had high phytase activities. The transcripts of Sphy1 could be detected in various tissues, such as cotyledons, leaves, stems and roots of seedlings. The phytase activities in the above tissues were in accordance with their corresponding Sphy1 transcripts. The transcripts of Sphy1 in cotyledons showed an increasing trend from 5 to 30 days after germination, suggesting that Sphy1 had involved the hydrolyses of the organic phosphorus compounds in seeds from the stages of early seed germination to young seedlings in soybean. Therefore, it was speculated that Sphy1 played an important role during the seed germination and the growth of the seedlings by releasing inorganic phosphorus (Pi) from phosphorus reserve in seeds.

Efficiency of reed beds in treating dairy wastewater

At dairy farms in the UK, dirty water is produced from dairy wash water, runoff from soiled yard areas and in some cases silage effluent. It typically contains organic matter, solid matter, nitrogen and phosphorus compounds and pathogens. The purpose of this paper is to test the hypothesis that reed beds can be used to treat high-strength agricultural effluent of 5-d biochemical oxygen demand (BOD5) up to 6000 mg l−1, following either dilution with treated water or pre-treatment such as intensive aeration. The experimental process was designed to treat up to 1/50th of the average volume of 25 m3 d−1 of wastewater produced on the farm. When 500 l d−1 wastewater had been pre-treated in an intensive aeration unit BOD5 removals of the order 98.6% occurred in the aeration plant, 75.1% in the reed bed and 99.6% in the whole system incorporating the reed bed. However, the supply of a smaller volume of 50 l d−1 of raw dirty water diluted with a recycle of 1100 l d−1 of treated water to the reed bed only, led to removal rates of BOD5 as low as 58%. A mathematical model based on the tidal flow of water and first-order BOD5 removal was applied to predict the outlet concentration of BOD5 from the reed beds. During the summer months the correlation between predicted and actual BOD5 was high, as indicated by a correlation coefficient (R2) of 0.882, but in the winter months the correlation was poorer, with a correlation coefficient of 0.763.

Distribution and diversity of phytate-mineralizing bacteria

Phytate, the most abundant organic phosphorus compound in soil, dominates the biotic phosphorus input from terrestrial runoffs into aquatic systems. Microbial mineralization of phytate by phytases is a key process for recycling phosphorus in the biosphere. Bioinformatic studies were carried out on microbial genomes and environmental metagenomes in the NCBI and the CAMERA databases to determine the distribution of the four known classes of phytase in the microbial world. The beta-propeller phytase is the only phytase family that can be found in aquatic environments and it is also distributed in soil and plant bacteria. The beta-propeller phytase-like genes can be classified into several subgroups based on their domain structure and the positions of their conserved cysteine residues. Analysis of the genetic contexts of these subgroups showed that beta-propeller phytase genes exist either as an independent gene or are closely associated with a TonB-dependent receptor-like gene in operons, suggesting that these two genes are functionally linked and thus may play an important role in the cycles of phosphorus and iron. Our work suggests that beta-propeller phytases play a major role in phytate-phosphorus cycling in both soil and aquatic microbial communities.

Development of Atomic Emission Detector for Gas Chromatography Equipped with Coaxial Micro Plasma Torch and Detection of Sulfur and Phosphorus Organic Compounds

ヘリウムラジオ波（RFP）プラズマを用いた同軸型マイクロプラズマトーチ内蔵のガスクロマトグラフィー（GC）用原子発光検出器（AED）を開発した．トーチは2本の白金管電極（外径1.0 mm及び外径0.5 mm）を同軸状に配置することにより作製した．光ファイバー先端をトーチ上に設置し，後端を小型CCD分光器に接続した．作製したAEDは市販のGCに搭載して測定に供した．含硫黄化合物としてチオアニソールを用いたとき，測定波長921.3 nm，印加電力3 W，メークアップガス流量1 mL/minで59 pg/s（S/N = 3）の検出感度を得た．含リン化合物としてリン酸トリエチルを用いた場合，測定波長253.4 nm，印加電力3 W，メークアップガス流量17 mL/minで検出感度は62 pg/s（S/N = 3）であった．既報のヘリウムRFP-AEDと比較して1けた少ない印加電力とメークアップガス流量で高感度測定が可能であった．

Detoxification Therapy in Critical States of Toxic Etiology

Objective: to improve the results of detoxification therapy for acute exogenous intoxications. Materials and methods. More than 20 thousand patients with intoxication caused by psychopharmacological agents, organic phosphorus compounds, chlorinated hydrocarbons, and other poisons, in whose treatment enhanced natural detoxification methods, as well as artificial detoxification methods and antidote therapy were used, were examined. Results. Complex detoxification should include efferent methods (hemosorption, hemo- and peritoneal dialysis and intestinal lavage, as well as physiohemotherapy (magnetic, laser, and ultraviolet) and chemohemotherapy with sodium hypochlorite) and should be composed of 2 basic stages: 1) to reduce for a short space of time (1—2 h) the blood poison level to the life-safe one (below the lethal or critical one) that promotes elimination of severe hemostatic disorders, wherein the leading role is played by efferent methods and chemohemotherapy and 2) to terminate a detoxifying process within 1—2 days, which is predominantly associated with the effect of physiohemotherapy as a potent stimulant of natural detoxification and which is achieved just via further stabilization of homeostatic disorders. In the somatogenic stage, detoxification is continued through the program use of physiochemical hemotheraupetic methods and drugs. Conclusion. Introduction of the above principle of complex detoxification performed by a certain algorithm contributes to the higher rate of freeing the blood and urine from exo- and endogenous toxicants by 1.4-12 times and to the significant (more than 2-fold) mortality reduction achieved in an intensive care unit, Moscow City Center of Acute Intoxication Management.

Effect of the type and concentration of lubricating additives on the antiwear and extreme pressure properties and rolling fatigue life of a four‐ball tribosystem

AbstractTests were performed on two different four‐ball testers. The first was used to determine antiwear (AW) and extreme pressure (EP) properties at sliding friction. The second was used to assess the surface fatigue (pitting) life at rolling movement. Lubricating oils of various chemical compositions were tested. A base mineral oil was blended with two different commercial packages of lubricating additives of AW and EP types. The AW additives contained ZDDP and were blended with the base oil at 0.2 and 3wt %. The EP additives were organic compounds of sulphur and phosphorus, blended with the base oil at 1 and 10wt %. It is shown that AW additives not only improve AW and EP properties but also — at 0.2% — are beneficial for the fatigue life. An increase in the concentration of AW additives leads to an improvement of AW and EP properties but — for one of the packages — reduces the fatigue life. EP additives — at 1% concentration — significantly improve EP properties, and to a lesser extent AW properties. Such a concentration of EP additives has no influence on the fatigue life. An increase in the concentration of EP additives leads to a further improvement of EP and AW properties. However, this is accompanied by a considerable decrease in the fatigue life. By using a scanning electron microscope and energy dispersive spectrometer for analysis of the worn surface, mechanisms of action of various lubricating additives under different friction conditions were identified. Copyright © 2006 John Wiley & Sons, Ltd.

Sorption Dynamics of Organic and Inorganic Phosphorus Compounds in Soil

Phosphorus retention in soils is influenced by the form of P added. The potential impact of one P compound on the sorption of other P compounds in soils has not been widely reported. Sorption isotherms were utilized to quantify P retention by benchmark soils from Indiana, Missouri, and North Carolina when P was added as inorganic P (Pi) or organic P (beta-D-glucose-6-phosphate, G6P; adenosine 5'-triphosphate, ATP; and myoinositol hexaphosphate, IP6) and to determine whether soil P sorption by these organic P compounds and Pi was competitive. Isotherm supernatants were analyzed for pH and total P using standard protocols, while Pi and organic P compounds were assayed using ion chromatography. Under the controlled conditions of this study, the affinity of all soils for P sources followed the order IP6 > G6P > ATP > Pi. Each organic P source had a different potential to desorb Pi from soils, and the order of greatest to least Pi desorption was G6P > ATP > IP6. Glucose-6-phosphate and ATP competed more directly with Pi for sorption sites than IP6 at greater rates of P addition, but at the lesser rates of P addition, IP6 actually desorbed more Pi. Inositol hexaphosphate was strongly sorbed by all three soils and was relatively unaffected by the presence of other P sources. Decreased total P sorption due to desorption of Pi can be caused by relatively small additions of organic P, which may help explain vertical P movement in manured soils. Sorption isotherms performed using Pi alone did not accurately predict total P sorption in soils.

Degradation of organic phosphorus compounds in anoxic Baltic Sea sediments: A 31P nuclear magnetic resonance study

The composition and abundance of phosphorus extracted by NaOH-ethylenediaminetetraacetic acid from anoxic Northwest Baltic Sea sediment was characterized and quantified using solution 31P nuclear magnetic resonance. Extracts from sediment depths down to 55 cm, representing 85 yr of deposition, contained 18.5 g m-2 orthophosphate. Orthophosphate monoesters, teichoic acid P, microbial P lipids, DNA P, and pyrophosphate corresponded to 6.7, 0.3, 1.1, 3.0, and 0.03 g P m-2, respectively. The degradability of these compound groups was estimated by their decline in concentration with sediment depth. Pyrophosphate had the shortest half-life (3 yr), followed by microbial P lipids with a half-life of 5 yr, DNA P (8 yr), and orthophosphate monoesters (16 yr). No decline in concentration with sediment depth was observed for orthophosphate or teichoic acid P.

Surfactant-sensitized malachite green method for trace determination of orthophosphate in aqueous solution

A surfactant-sensitized spectrophotometric method for determination of trace orthophosphate has been developed using anion surfactant (Ultrawet 60 L) with molybdate and malachite green in low acidic medium (pH T 1.0). The method detection limit (3 × standard deviation of blank, n = 10) was 8 nM and the calibration curve was linear over a range of 10–400 nM ( r 2 = 0.997). The molar absorptivity was 1.26 × 10 5 L mol −1 cm −1 at 600 nm with the background correction at 530 nm. The precision of method was 3.4% at 50 nM and 2.4% at 100 nM orthophosphate ( n = 10). The hydrolysis of eight organic phosphorus and polyphosphate compounds was less than 2% of the total phosphorus present (5–10 μM). This method showed less arsenate interference than previous methods, with only 3% even in the presence of orthophosphate in the samples. No interference of silicate up to 40 μM was observed. Background anions (in an order of SO 4 2− > NO 3 − > Cl −) have greater effects than cations (Ca 2+ > Mg 2+ > Na +) on the reagent blank and the molar absorptivity of the color product.

Spatial and temporal variability of the ratios between the nitrate and phosphate concentrations in the Sea of Okhotsk

The relation between the nitrate and phosphate concentrations in the Sea of Okhotsk and the bordering waters of the Pacific Ocean were studied. The surveys were carried out in the autumn, spring, and summer of 2001–2002. For the deepwater part of the sea, the relation [NO−3] = ((14.88 ± 0.07) × [PO3−4] − 5.46 ± 0.17) was found. The coefficients in the equation given are statistically different from those in the similar equation for the Pacific waters: [NO−3] = (16.05 ± 0.15) × [PO3−4]-(7.23 ± 0.36). In the northern part of the sea; on the shelf; in the slope area; and, especially, in the deep waters of the TINRO Depression, the linear dependence between the phosphate and nitrate concentrations was distorted. This feature was described in terms of nitrate deficiency. The maximum values of this deficiency were found in the near-bottom waters. The principal processes that might cause the nitrate deficiency were considered: the difference in the oxidation rates of the nitrogen and phosphorus organic compounds, the matter transfer between the continent and the sea, the different efficiency of the biogenic burial of nitrogen and phosphorus in the bottom sediments, and the denitrification in the upper layer of the bottom sediments. It was shown that the most probable cause of the nitrate deficiency was the denitrification. The loss of inorganic nitrogen owing to the supply of the waters of the Sea of Okhotsk to the Pacific Ocean was estimated as ∼2.5 × 1011 mol N/year.

Beta-propeller phytases in the aquatic environment

Phytate, which is one of the dominant organic phosphorus compounds in nature, is very stable in soils. Although a substantial amount of phytate is carried from terrestrial to aquatic systems, it is a minor component of organic phosphorus in coastal sediments. The ephemeral nature of phytate implies the rapid hydrolysis of phytate under aquatic conditions. Among the four classes of known phytases that have been identified in terrestrial organisms, only beta-propeller phytase-like sequences have been identified in the aquatic environment. A novel beta-propeller phytase gene (phyS), cloned from Shewanella oneidensis MR-1, was found to encode a protein with two beta-propeller phytase domains. The characterization of recombinant full-length PhyS and its domains demonstrated that Domain II was the catalytic domain responsible for phytate hydrolysis. The full-length PhyS displayed a K(m) of 83 microM with a kcat of 175.9 min(-1) and the Domain II displayed a K(m) of 474 microM with a kcat of 10.6 min(-1). These results confirm that the phyS gene encodes a functional beta-propeller phytase, which is expressed in S. oneidensis under phosphorus deficient condition. The presence of multiple sequences with a high similarity to phyS in aquatic environmental samples and the widespread occurrence of the Shewanella species in nature suggest that the beta-propeller phytase family is the major class of phytases in the aquatic environment, and that it may play an important role in the recycling of phosphorus.

Polynomial Dependence for the Calculation of Vaporization Enthalpies of Organophosphorus Compounds

Enthalpies of vaporization of organic phosphorus compounds are related to the normal-pressure boiling points through a polynomial dependence. Each class of organophosphorus compounds is characterized by its own specific parameters of the general dependence. The polynomial dependences may be used for the calculation of vaporization enthalpies of organophosphorus compounds with different modes of phosphorus coordination.

Mass spectrometry of natural organic phosphorus

This article provides a review of the use of modern mass spectrometry (MS) for quantitative and qualitative measurements of organic phosphorus compounds in nature. Included is a brief discussion of recent developments in large molecule mass spectrometry, focusing on time-of-flight (TOF) and ion cyclotron resonance (ICR) mass analysis techniques, as well as electrospray (ESI) and inductively coupled plasma (ICP) ionization. The use of ICP with high-resolution mass spectrometry for quantitative measurements of total phosphorus and as a detector coupled to HPLC and CE for defining organic phosphorus speciation is demonstrated using results from a study of phosphorus cycling in a treatment wetland. Qualitative identifications of individual phosphorus compounds by ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is demonstrated using dissolved organic phosphorus isolated from this same wetland.