Form Of Orthophosphate Research Articles

Elucidating the Redox Cycle of Environmental Phosphorus Using Ion Chromatography

Historically, it was assumed that reactive, inorganic phosphorus present in pristine environments was solely in the form of orthophosphate. However, this assumption contradicts theories of biogenesis and the observed metabolic behavior of select microorganisms. This paper discusses the role of ion chromatography (IC) in elucidating the oxidation-reduction cycle of environmental phosphorus. These methods employ suppressed-IC, coupled with tandem conductivity and electrospray mass spectrometry detectors to identify and quantify phosphorus oxyanions in natural water, synthetic cosmochemical, and biological samples. These techniques have been used to detect phosphite and orthophosphate in geothermal hot springs. Hypophosphite, phosphite, and orthophosphate have been detected in synthetic schreibersite corrosion samples, and termite extract supernatant. Synthetic schreibersite corrosion samples were also analyzed for two poly-phosphorus compounds, hypophosphate and pyrophosphate, and results show these samples did not contain concentrations above the 1.3 and 2.0 μM respective 3σ limit of detection. These methods are readily adaptable to a variety of matrices, and contribute to the elucidation of the oxidation-reduction cycle of phosphorus oxyanions in the environment. In contrast to most studies, these techniques have been used to show that phosphorus actively participates in redox processes in both the biological and geological world.

Cloud point extraction for the spectrophotometric determination of phosphorus(V) in water samples

A rapid, selective and sensitive cloud point extraction process using the nonionic surfactant, Triton X-114, to extract phosphorus in the form of orthophosphate from aqueous solutions was investigated. The method is based on the color reaction of orthophosphate with molybdate in acidic medium and in the presence of Sb(III) and ascorbic acid, then cloud point extraction of phosphomolybdenum blue in micellar medium. Effects of reaction and extraction parameters were studied and optimum parameters were established. The analytical characteristics of the method (e.g., limit of detection, linear range, relative standard deviation) were obtained. Linearity was obeyed in the range of 1.0–125 ng mL −1 of P. The detection limit of the method was 0.5 ng mL −1 of P. The interference effect of some common ions was also tested. The method was applied to the determination of orthophosphate in natural water samples.

Ocean productivity before about 1.9 Gyr ago limited by phosphorus adsorption onto iron oxides.

After the evolution of oxygen-producing cyanobacteria at some time before 2.7 billion years ago, oxygen production on Earth is thought to have depended on the availability of nutrients in the oceans, such as phosphorus (in the form of orthophosphate). In the modern oceans, a significant removal pathway for phosphorus occurs by way of its adsorption onto iron oxide deposits. Such deposits were thought to be more abundant in the past when, under low sulphate conditions, the formation of large amounts of iron oxides resulted in the deposition of banded iron formations. Under these circumstances, phosphorus removal by iron oxide adsorption could have been enhanced. Here we analyse the phosphorus and iron content of banded iron formations to show that ocean orthophosphate concentrations from 3.2 to 1.9 billion years ago (during the Archaean and early Proterozoic eras) were probably only approximately 10-25% of present-day concentrations. We suggest therefore that low phosphorus availability should have significantly reduced rates of photosynthesis and carbon burial, thereby reducing the long-term oxygen production on the early Earth--as previously speculated--and contributing to the low concentrations of atmospheric oxygen during the late Archaean and early Proterozoic.

Phosphate accumulation by an extremely halophilic archae Halobacterium salinarium

Halobacterium salinarium, an extremely halophilic archae, is capable of consuming up to 95% of phosphate from culture medium. For growth, H. salinarium needs high concentrations of phosphate in the medium. At P i concentrations of 0.05, 2.3 and 11.5 mM the maximum amounts of biomass were 2, 5 and 12 g/l, respectively. Most P i was present in biomass as magnesium ortho-phosphate, the amount of which by the early stationary phase may reach near 90% from phosphate consumed by the cells. H. salinarium contains inorganic polyphosphate (polyP) in amounts comparable with those in eubacteria and yeast. However, the phosphorus of polyP was not more than 10% of all the phosphorus accumulated in the culture. H. salinarium is able to use the reserves of phosphorus both in the form of ortho-phosphate and in the form of polyP for growth on medium at minimum phosphate concentration (0.05 mM). In contrast with eubacteria and yeast the main reserve of phosphate in this archae is magnesium ortho-phosphate.

High specificity of a phosphate transport protein determined by hydrogen bonds

Transport of the essential nutrient phosphorus--primarily in the form of orthophosphate--into cells and organelles is highly specific. This is exemplified by the uptake of phosphate or its close analogue arsenate by bacterial cells by way of a high affinity active transport system dependent on a phosphate-binding protein; this system is unable to recognize other inorganic oxyanions and is, moreover, distinct from the one for sulphate transport. The phosphate-binding protein is a member of a family of periplasmic proteins acting as initial high-affinity receptors for the osmotic shock-sensitive active transport systems or permeases for various sugars, amino acids, oligopeptides, and oxyanions. We report here the highly refined 1.7 A resolution X-ray structure of the liganded form of the phosphate-binding protein. The structure reveals the atomic features responsible for phosphate selectivity, either in monobasic or dibasic form, and the exclusion of sulphate. These features are fundamental to understanding phosphate transport systems and molecular recognition of charged substrates or ions in other biological processes.

Slaughterhouse effluent treatment by thermophilic aerobic process

A pig slaughterhouse effluent was submitted to laboratory runs in order to assess the potentiality of the thermophilic aerobic process for the treatment of meat processing industry's effluents. A mixed aerobic bacterial culture was successfully maintained at 52 and 58°C in a semi-continuously fed bioreactor, without recycling the cells. Operation was conducted at 6, 12, 18, 24 and 30 h of solids retention time. Over 93% of the CODs (Chemical Oxygen Demand) were removed during the treatment at 52°C for all the retention times investigated, as compared to 86% of removal at 58°C, with an exception for the case of 6 h retention time. Reduction of phosphorus in the form of orthophosphate ranged between 72–90% with the best efficiency noted at 52°C and 6 h retention time. Extremely high specific utilization rates ( q m) were observed and revealed that the process is about 10 times faster than the mesophilic process for slaughterhouse effluent treatment. Biokinetics parameters μ m (maximal specific growth rate) and k d (endogenous respiration coefficient) were evaluated by fitting to appropriate mathematical models. They were found superior to those reported in the literature for mesophilic process, with the exception of the Y (actual yield) coefficient which is of the same magnitude. High k d values had a marked effect on the apparent yield of sludges which showed low values as compared to those found in mesophilic systems.

Fertigation of apples with nitrate or ammonium nitrogen under drip irrigation. II. Nutrient distribution in the soil

Abstract Nutrient distribution in the soil under drip irrigation was monitored by soil sampling and analysis of soil solution collected by vacuum suction through ceramic cups buried in the soil near the drippers. Concentration of ammonium and nitrate nitrogen, phosphate and potassium, and the pH were monitored in three fertigation treatments with N fertilizers containing 0, 50 or 100% NH4 +. All treatments received equal annual doses of nitrogen (128 kg/ha) and potassium (356 kg/ha). The 50% and 100% NH4 + treatments received also P (185 kg/ha) in the form of orthophosphate and polyphosphate, respectively. Only traces of NH4 + (1–2 ppm) could be detected in the soil solution. The NO3 concentration in the soil solution was proportional to the quantity of nitrate in the fertilizer, and was built up in the soil gradually every year as fertigation commenced. Nitrate concentration in the soil solution varied widely between years. Phosphate concentration was raised from 0–4 ppm to 10–20 ppm in the soil solution...

Variation of cellular phosphorus composition of Skeletonema costatum and Heterosigma akashiwo grown in chemostats

Two coastal species of phytoplankton, Skeletonema costatum (Grev.) Cleve and Heterosigma akashiwo Hada, were grown in chemostats at a constant dilution (growth) rate using media with various P:N ratios. The variations of their cellular phosphorus composition were investigated using a phosphorus fractionation technique and 31P nuclear magnetic resonance spectroscopy. S. costatum stores phosphorus mainly in the form of orthophosphate, and H. akashiwo in the form of polyphosphates. This explains the orthophosphate accumulation observed in natural phytoplankton populations in Tokyo Bay where S. costatum is dominant.

Preliminary studies of the fertilizer capability of some novel high analysis multinutrient compounds

In a preliminary assessment of the fertilizer capability of three high analysis NP(S) compounds, their possible phytotoxic effects were investigated in solution culture tubes. One of the compounds was studied in more detail in pot experiments with sand and a red-brown earth soil. Two adamantane-type compounds (APA and APAS) were capable of supplying N and P to plants, but also showed toxicity effects. With APA, this effect appeared to be dissipated in soil but not in sand. The toxic effect was alleviated by addition of soluble P or soluble P + N. Some plants absorbed excessive amounts of P, probably not all in the form of orthophosphate.

THE PHOSPHORUS METABOLISM OF RHIZOPUS STOLONIFER AND CHAETOMIUM SP. WITH RESPECT TO PHOSPHORUS TRANSLOCATION

Summary Rhizopus stolonifer was able to translocate 32phosphorus readily through established hyphae, whereas Chaetomium sp. was unable to do so. When colonies of either species were incubated on KH232PO4 a range of compounds became labelled in the mycelium but a substantial proportion of absorbed 32P was present in the form of orthophosphate in both species. After incubating 32P‐labelled mycelium of Rhizopus stolonifer on unlabelled KH2PO4, the proportion of 32P detected in the form of orthophosphate was unchanged. When mycelium of Chaetomium sp. was treated in this way the proportion of label in the orthophosphate fraction was greatly reduced. Mycelium of Rhizopus stolonifer was able to take up hexose [32P] phosphate intact and subsequently hydrolyse it to orthophosphate. In Chaetomium sp. very little 32P derived from hexose [32P] phosphate appeared as orthophosphate.These results are held to support the view that the ability to translocate phosphorus is associated with rapid turnover of phosphorus compounds.

THE EFFECT OF TEMPERATURE ON THE TRANSLOCATION OF PHOSPHORUS BY RHIZOPUS STOLONIFER

SummaryThe effect of temperature on the rate of phosphorus translocation, on the uptake and metaholism of phosphate and on respiratory rate of Rhizopus stolonifer, has been studied. Over the temperature range 20–30° C the rate of phosphorus translocation is greatest at 20° C and lowest at 30° C. The rate of oxygen uptake is greatest at 25° C. The rate of phosphate uptake does not vary significantly over this temperature range, but the proportion of ahsorhed phosphate present as orthophosphate bears a direct relationship to the rate of phosphorus translocation. These results are consistent with the view that phosphorus may be translocated in the form of orthophosphate.

Site of phosphorus absorption of the sheep.

THOUGH several reports1–4 deal with phosphorus uptake by the various divisions of the gastro-intestinal tract of the sheep, they do not compare the absorption of added physiological amounts of phosphorus from normal ingesta in these organs. To satisfy this requirement sheep were allowed to graze normally until approximately four hours before being anaesthetized. The organ under investigation was then tied off and radiophosphorus, in the form of orthophosphate with 1 mgm. per me. carrier, injected into it. Blood samples were taken, at intervals, from the left jugular vein, and the plasma assayed for radioactivity in a dipping counter.