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PubMed1996

Effects of dietary aluminum on chicks Gallus gallus domesticus with different dietary intake of calcium and phosphorus.

Birds that feed in acidified areas may be exposed to an increased intake of aluminum, while their intake of calcium and phosphorus may simultaneously be low. In particular, juvenile birds foraging in acidified areas may suffer from increased effects of aluminum due to high demands of calcium. Day old chicks were fed six different diets where aluminum was combined with normal and low concentrations of dietary calcium and phosphorus for 14 days. The normal calcium-available phosphorus (Ca-P) level was 1.05%-0.45%, and the low dietary Ca-P level was 0.49%-0.21%. Aluminum was given in dietary levels of 0%, 0.13%, and 0.31%. Aluminum had no effects on growth, mortality, or hematocrit, but induced hypocalcemia. Bones accumulated more aluminum than kidneys. A high dietary concentration of aluminum (0.31%) increased the accumulation of aluminum twofold in bones and threefold in kidneys when the dietary concentration of calcium and phosphorus was halved. Opposed to the predictions, bone mineralisation was stimulated by an intermediate increase in dietary aluminum (0.13%) at both levels of dietary calcium and phosphorus. Bone stiffness was also stimulated at this dietary aluminum concentration, but only at the diet low in calcium and phosphorus. A high dietary aluminum concentration did not have any effect on bone stiffness or calcium concentration. Bone stiffness correlated positively with the calcium concentration in bone, and negatively with the aluminum concentration in bone. The effect of dietary aluminum on bone stiffness is probably caused by an alteration in bone mineralization, rather than by the presence of aluminum in bones.

Administration, Oral↗
PubMed1977

Phosphorus, a key to life on the primitive Earth.

The phosphorus of the primitive Earth was present as phosphates. It is strongly probably that a portion of the phosphate was present as condensed phosphates. The primitive Earth was highly deficient in the total available phosphorus until a sufficient quantity of phosphorus weathered from the igneous rocks in which it was entrapped. Approximately three billion years were required for the seas to become saturated. Until this time passed the seas acted as a giant sink for phosphorus, diluting it to the extent that all forms of life were deprived of the vital nutrient. When the seas became saturated, the rate of turn over of the phosphorus increased rapidly. As the seas pulsated, they left the excess precipitate phosphorus as sedimentary rock in locally righ deposits on which life could thrive.

Apatites↗
PubMed1976

The effect of fluoride on bone of rats fed diets deficient in calcium or phosphorus.

Four groups of weanling rats were fed for 2 weeks on a diet sufficient or insufficient in calcium and/or phosphorus. Each group was divided into four subgroups which were offered distilled water supplemented with 0, 50, 75, or 150 ppm fluoride. High levels of fluoride in drinking water inhibited weight gain. This inhibition was less in rats deficient in phosphorus than when normal-phosphorus diets were offered. At a low level, fluoride was without any effect on bone ash, thickness of femoral cortical bone, and mechanical strength, as measured by maximal load, ultimate stress to breaking, and limit of elasticity. Modulus of elasticity was decreased. At higher levels fluoride tended to decrease most of these parameters, except in rats deprived of both calcium and phosphorus. The effect of fluoride was modified by lack of dietary calcium and/or phosphorus and appeared to be weaker in rats deficient in these nutrients. Lack of dietary calcium and/or phosphorus decreased bone strength more than did fluoride content of water and of bone mineral. Concentration of bone ash and thickness of femoral cortical bone were closely correlated with parameters of mechanical strength.

Animals↗
PubMed1987

Seasonal variations in plasma phosphorus levels of transhumant sheep in Kordofan, Sudan.

Plasma phosphorus levels were evaluated for one hundred adult breeding ewes from transhumant producer flocks during the late rainy season (September 1984/1985), the mid-dry season (February 1985) and the late-dry season (May 1985). The percentage of non-pregnant/non-lactating ewes critically deficient in phosphorus increased from 9% in the rainy season to 56% in the late-dry season. In September 35% of pregnant ewes were critically deficient in phosphorus. During peak lactation (February) 87% of lactating ewes were critically deficient in phosphorus and 84% remained critically deficient until the start of the rainy season approximately 20 weeks postlambing. The low phosphorus content of grazing rations, which varied from 0.18% in the rainy season to 0.09% in the dry season, and low forage availability, which was especially acute during the late-dry season, appeared to be the most important factors limiting phosphorus intake.

Animals↗
PubMed2002

Remediation of heavy metal-contaminated soils using phosphorus: evaluation of bioavailability using an earthworm bioassay.

This study investigated the effectiveness of phosphorus (P) as an in situ remediation technique in site soils collected from the Tri-State mining area. The site soils were treated with two different types (KH(2)PO(4) and Super Triple Phosphate fertilizer) and levels (600 and 5,000 mg/kg) of phosphorus. A toxicokinetic approach was used to determine whether phosphorus amendments reduced heavy metal bioavailability to the earthworm Eisenia fetida. Bioaccumulation factors were used as a measure of bioavailability. Depuration patterns of lead, zinc, and cadmium also were studied after removing earthworms from contaminated soils and then placing them in noncontaminated artificial soil. Results showed that the high phosphorus treatments significantly reduced lead, zinc, and cadmium bioavailability to the earthworms, probably due to formation of metal-phosphate complexes in the soils. Results also indicated that other soil characteristics in addition to amended phosphorus have an affect on bioavailability. Depuration experiments showed a biphasic elimination pattern for each metal. The current results indicate that phosphorus soil amendments may reduce ecological risk to soil-inhabiting invertebrates exposed to heavy metal-contaminated soils.

Animals↗
PubMed2006

Consequences of nitrogen and phosphorus limitation for the performance of two planthoppers with divergent life-history strategies.

Phytophagous insects have a much higher nitrogen and phosphorus content than their host plants, an elemental mismatch that places inherent constraints on meeting nutritional requirements. Although nitrogen limitation is well documented in insect herbivores, phosphorus limitation is poorly studied. Using factorial experiments in the laboratory and field, in which levels of soil nitrogen and phosphorus were manipulated, we studied the relative consequences of macronutrient limitation for two herbivores, namely the phloem-feeding planthoppers Prokelisia dolus and P. marginata. These planthoppers inhabit the salt marshes of North America where large stands of their Spartina host plant are found. Notably, these congeners differ in their dispersal abilities; P. marginata is dispersive whereas P. dolus is sedentary. Both nitrogen and phosphorus subsidies enhanced the nitrogen and phosphorus content of Spartina. When P. dolus and P. marginata were raised on plants with an enriched nitrogen signature, they exhibited greater survival, grew to a larger size, developed more rapidly, and achieved higher densities than on nitrogen-deficient plants. However, P. marginata experienced greater fitness penalties than P. dolus on nitrogen-deficient plants. Phosphorus limitation and associated fitness penalties were not as severe as nitrogen limitation for P. marginata, and were not detected in P. dolus. The tempered response of P. dolus to N- and P-deficient Spartina is probably due to its greater investment in feeding musculature and hence ability to compensate for nutrient deficiencies with increased ingestion. To cope with deteriorating plant quality, P. dolus employs compensatory feeding, whereas P. marginata disperses to higher quality Spartina. When its option of dispersal is eliminated and P. marginata is confined on nutrient-deficient plants, its performance is drastically reduced compared with P. dolus. This research highlights the importance of interfacing herbivore life-history strategies with ecological stoichiometry in order to interpret the consequences of macronutrient limitation on herbivore performance and population dynamics.

Animals↗
PubMed1994

Reduction of dietary protein and phosphorus in the Modification of Diet in Renal Disease Feasibility Study. The MDRD Study Group.

OBJECTIVE AND DESIGN: The Modification of Diet in Renal Disease (MDRD) Feasibility Study was designed to test procedures and evaluate the feasibility of a full-scale clinical trial aimed at assessing the effects of reduction of dietary protein and phosphorus on progression of renal disease. SETTING AND SUBJECTS: Ninety-six patients with chronic renal insufficiency were randomly assigned to different diets in one of two studies depending on their glomerular filtration rate. INTERVENTION: The diets contained three different protein and phosphorus levels: moderate diet = 1.3 g protein per kilogram per day and 16 to 20 mg phosphorus per kilogram per day; low diet = 0.575 g protein per kilogram per day and 5 to 10 mg phosphorus per kilogram per day; and very low diet with keto or amino acids = 0.28 g protein per kilogram per day and 4 to 9 mg phosphorus per kilogram per day. Eight-five patients were monitored for at least 6 months; maximum follow-up was 22 months. MAIN OUTCOME MEASURES: Compliance with study diets was measured monthly using urea nitrogen appearance and 3-day diet diaries plus one 24-hour recall. The main outcome measure was change or maintenance of glomerular filtration rate. STATISTICAL ANALYSES PERFORMED: Data were analyzed by analysis of variance and paired t tests. RESULTS: Mean dietary protein intake, as determined by urea nitrogen appearance, decreased significantly in participants assigned to the diets low and very low in protein and phosphorus (P < .05). Overall, the follow-up protein intake (based on urea nitrogen appearance) as a percentage of baseline ranged from 45.8% to 83.1%. Analysis of diet diaries showed better dietary adherence than indicated by urea nitrogen appearance. Review of the exchange methodology used in dietary instruction suggests that imprecision of the exchange lists may have been a factor in the difficulty study participants had in achieving +/- 10% of the target protein goal. APPLICATIONS: Based on the MDRD Feasibility Study, the protocol for the full-scale study was modified to include protein counting instead of food exchange methodology to monitor protein intake.

Amino Acids↗
PubMed1982

The correlation between bismuth and uranyl staining and phosphorus content of intracellular structures as determined by electron spectroscopic imaging.

Four groups of intracellular structures can be recognized according to bismuth and uranyl staining and phosphorus content. (1) Those which contain phosphorus and stain strongly with uranyl acetate but not with bismuth (ribosomes, heterochromatin and mature ribosomal precursor granules), presumably because of their nucleic acid content. (2) Those which contain phosphorus and stain with uranyl acetate and bismuth (interchromatin granules, immature ribosomal precursor granules and mitochondrial granules), presumably because at least some of their phosphate is available to react with bismuth. (3) Those which contain little phosphorus but which stain strongly with bismuth and weakly with uranyl acetate (Golgi complex beads), perhaps because some ligand in addition to phosphate reacts with bismuth, and (4) those which do not contain phosphorus and stain with neither uranyl acetate nor bismuth (portasomes). Uranyl staining correlates strongly with the phosphorus content of nucleic acids, proteins and inorganic deposits. Bismuth will stain some phosphorylated molecules but not all. Thus only some phosphates stain with bismuth.

Animals↗
PubMed1986

Studies on the mechanism of diet-induced nephrocalcinosis: calcium and phosphorus metabolism in the female rat.

The disposition of calcium and phosphorus in female Sprague-Dawley rats fed either a low- or a high-calcium semi-synthetic diet for up to 9 wk from weaning has been investigated. The rats fed the low-calcium diet (calcium to phosphorus ratio approximately 1:1) developed cortico-medullary nephrocalcinosis within 6 wk, whereas those fed the high-calcium diet (calcium to phosphorus ratio greater than 1.5:1) did not develop any lesion during this time. Intake and excretion of calcium was greater at all times in the animals fed the high-calcium diet than in those on the low-calcium diet. However, the true absorption and retention of calcium was not significantly different between the two diet groups. Phosphorus intake and total excretion were similar for both groups of animals, although urinary excretion accounted for less than 1% of the total in the animals fed the high-calcium diet but more than 50% in those fed the low-calcium diet. Bioavailability of phosphorus decreased with age in both groups. Recovery of injected 45Ca in urine and faeces increased during the experimental period from approximately 3 to 11% of the dose in rats on the low-calcium diet and from approximately 9 to 13% in the high-calcium group. Recovery of both injected and orally administered 32P was substantially greater in the low-calcium group than in the high-calcium group at wk 3 and 5, but at wk 9 was only greater after intramuscular administration. At the earlier times the urine was the major route of 32P excretion. It appears that no gross disturbances of calcium or phosphorus metabolism occurred in female rats maintained on a diet that resulted in the rapid development of kidney calcification.

Absorption↗
PubMed1990

The effects of uremia and dietary phosphorus on the bone of rats.

In order to evaluate the effects of uremia and low levels of dietary phosphorus on bone, male Sprague-Dawley rats weighing 320 +/- 20 g (12 weeks old) were subjected to either a two-step, subtotal nephrectomy or sham-operation (SO), and then fed a custom diet with either normal calcium (0.5%) and normal phosphorus (0.3%) (NCNP), or normal calcium and low phosphorus (0.03%). When compared to the NCNP SO group after seven days, only uremic rats fed low phosphorus diets developed osteomalacia characterized by an increase in the osteoid thickness, surface and volume, a prolonged osteoid maturation time, and a decreased bone formation rate. No other groups developed these changes. This osteomalacia was also associated with hypophosphatemia, a reduced serum PTH and an elevation in the serum 1,25(OH)2D3. It was concluded that while neither this degree of uremia nor the low phosphorus diets alone had any significant effect, the combination of uremia and low dietary phosphorus resulted in the initiation of osteomalacia. This animal model should prove useful in investigations dealing with the influence of uremia on the mineralization process.

Animals↗
PubMed2005

Competition between polyphosphate and glycogen accumulating organisms in enhanced biological phosphorus removal systems with acetate and propionate as carbon sources.

Enhanced biological phosphorus removal (EBPR) is a widely used process for achieving phosphorus removal from wastewater. A potential reason for EBPR failure is the undesirable growth of glycogen accumulating organisms (GAOs), which can compete for carbon sources with the bacterial group responsible for phosphorus removal from wastewater: the polyphosphate accumulating organisms (PAOs). This study investigates the impact of carbon source on EBPR performance and the competition between PAOs and GAOs. Two sequencing batch reactors (SBRs) were operated during a 4-6 month period and fed with a media containing acetate or propionate, respectively, as the sole carbon source. It was found that the acetate fed SBR rarely achieved a high level of phosphorus removal, and that a large portion of the microbial community was comprised of "Candidatus Competibacter phosphatis", a known GAO. The propionate fed SBR, however, achieved stable phosphorus removal throughout the study, apart from one brief disturbance. The bacterial community of the propionate fed SBR was dominated by "Candidatus Accumulibacter phosphatis", a known PAO, and did not contain Competibacter. In a separate experiment, another SBR was seeded with a mixture of PAOs and a group of alphaproteobacterial GAOs, both enriched with propionate as the sole carbon source. Stable EBPR was achieved and the PAO population increased while the GAOs appeared to be out-competed. The results of this paper suggest that propionate may provide PAOs with a selective advantage over GAOs in the PAO-GAO competition, particularly through the minimisation of Competibacter. Propionate may be a more suitable substrate than acetate for enhancing phosphorus removal in EBPR systems.

Acetates↗
PubMed2005

Effects of light and oxygen on the uptake and distribution of phosphorus at the sediment-water interface.

Effects of oxygen and light on the uptake and distribution of phosphorus at the sediment-water interface were investigated in this study. The experimental water and sediment samples were collected from East Taihu Lake, China. The results show that phosphorus can be taken up from the overlying water to the sediments with high nutrient loading in both anoxic and aerobic conditions. The transformation between different phosphorus fractions in the sediments and in the overlying water was observed. Effects of dissolved oxygen on the phosphorus distribution at the sediment and overlying water interface were mainly due to the inorganic processes, while effects of light were mainly due to the biological activity. This study indicates that oxygen concentration had a predominant control on the distribution and uptake of phosphorus in the sediments, and light had obvious effect on the dissolved inorganic phosphorus (DIP) concentration in the overlying water.

China↗
PubMed2006

Quantification and thickness correction of EFTEM phosphorus maps.

We describe a method for correcting plural inelastic scattering effects in elemental maps that are acquired in the energy filtering transmission electron microscope (EFTEM) using just two energy windows, one above and one below a core edge in the electron energy loss spectrum (EELS). The technique is demonstrated for mapping low concentrations of phosphorus in biological samples. First, the single-scattering EELS distributions are obtained from specimens of pure carbon and plastic embedding material. Then, spectra are calculated for different specimen thicknesses t, expressed in units of the inelastic mean free path lambda. In this way, standard curves are generated for the ratio k0 of post-edge to pre-edge intensities at the phosphorus L2,3 excitation energy, as a function of relative specimen thickness t/lambda. Thickness effects in a two-window phosphorus map are corrected by successive acquisition of zero-loss and unfiltered images, from which it is possible to determine a t/lambda image and hence a background k0-ratio image. Knowledge of the thickness-dependent k0-ratio at each pixel thus enables a more accurate determination of the phosphorus distribution in the specimen. Systematic and statistical errors are calculated as a function of specimen thickness, and elemental maps are quantified in terms of the number of phosphorus atoms per pixel. Further analysis of the k0-curve shows that the EFTEM can be used to obtain reliable two-window phosphorus maps from specimens that are considerably thicker than previously possible.

Animals↗
PubMed2004

Recent advances in removing phosphorus from wastewater and its future use as fertilizer (1997-2003).

Large quantities of phosphate present in wastewater is one of the main causes of eutrophication that negatively affects many natural water bodies, both fresh water and marine. It is desirable that water treatment facilities remove phosphorus from the wastewater before they are returned to the environment. Total removal or at least a significant reduction of phosphorus is obligatory, if not always fulfilled, in most countries. This comprehensive review summarizes the current status in phosphorus-removal technologies from the most common approaches, like metal precipitation, constructed wetland systems, adsorption by various microorganisms either in a free state or immobilized in polysaccharide gels, to enhanced biological phosphorus removal using activated sludge systems, and several innovative engineering solutions. As chemical precipitation renders the precipitates difficult, if not impossible, to recycle in an economical industrial manner, biological removal opens opportunities for recovering most of the phosphorus and beneficial applications of the product. This review includes the options of struvite (ammonium-magnesium-phosphate) and hydroxyapatite formation and other feasible options using, the now largely regarded contaminant, phosphorus in wastewater, as a raw material for the fertilizer industry. Besides updating our knowledge, this review critically evaluates the advantage and difficulties behind each treatment and indicates some of the most relevant open questions for future research.

Chemical Precipitation↗
PubMed1987

Achievement of in utero retention of calcium and phosphorus accompanied by high calcium excretion in very low birth weight infants fed a fortified formula.

Calcium and phosphorus retention was evaluated in 13 very low birth weight infants who were fed an experimental formula designed to deliver quantities of calcium and phosphorus sufficient to meet the intrauterine accretion rates for these minerals. Retention of calcium and phosphorus in slight excess of these rates was achieved without any apparent difficulties for the infants. Biochemical measurements demonstrated normal serum calcium (9.8 +/- 8 mg/dL) and alkaline phosphatase (242 +/- 51.6 IU) values. However, there was evidence of high tubular reabsorption of phosphate (98.1% +/- 3.3%), hypercalciuria (7.2 +/- 3.8 mg/kg/d), and a relatively low serum phosphorus concentration (5.7 +/- 0.6 mg/dL). This biochemical picture is similar to that seen in phosphorus deficiency except for the low alkaline phosphatase activity. The latter finding, in concert with the high retention of calcium and phosphorus in these balance studies, makes such a diagnosis unlikely. We speculate that this biochemical picture is the result of an inappropriately high calcium/phosphorus ratio.

Alkaline Phosphatase↗
PubMed2001

The role of extracellular exopolymers in the removal of phosphorus from activated sludge.

Biological phosphorus removal in activated sludge systems is thought to be a result of the action of polyphosphate accumulating organisms (PAO). However, not all phosphorus removed can be accounted for by PAO. A method for the qualitative in situ characterization of PAO cell clusters and closely associated extracellular exopolymers (EPS) is described. X-ray microanalysis was performed on samples from two activated sludge plants situated in Pretoria, South Africa. Analysis was done by means of scanning electron microscopy combined with energy dispersive spectrometry (EDS). Cell clusters with associated EPS, on average, contained between 57% and 59% phosphorus, while EPS alone contained, on average, between 27% and 30% phosphorus. Results suggest that phosphorus removal in activated sludge might be due not only to PAO, but also by EPS acting as a phosphorus reservoir.

Bacteria↗
PubMed2002

The effect of the physical structure of a porous Ca-based sorbent on its phosphorus removal capacity.

A macroporous calcium-based sorbent made from bentonite, calcium hydroxide and Yalloun coal was prepared and tested for its phosphorus removal performance. The coal was added as a solid pore-forming agent. Pores sizes as large as a few micron were generated when the Yalloun coal was incorporated at a relatively high proportion. These pores were formed due to the burning out of the added coal during the thermal treatment conducted at 700 degrees C. Results of phosphorus removal experiments showed that the increase of the amount of phosphorus removed could be positively correlated with the increase of the total pore volume and the mean pore size. Decreases in pore sizes and total pore volume were pronounced in sorbents used to remove phosphorus due to the formation of a Ca-phosphate mineral on their surfaces. It was suggested that the widely formed pores avoided the rapid plugging and contributed to maintain the diffusional transport of the substrate to a certain extent. Hydroxyapatite was formed and coated on the surface of the sorbent during phosphorus removal. On the basis of these results, it was concluded that modification of the physical structure of Ca-based sorbents by creating large pore sizes, revealed to be effective for increasing their phosphorus uptake.

Adsorption↗
PubMed2002

Phosphorus fractionation in lake sediments--lakes Volvi and Koronia, N. Greece.

Sediments from two lakes, the meso-to-eutrophic Volvi and the hypertrophic Koronia, located in N. Greece were examined on the basis of P-fractionation. In both lakes, the rank order of P-fractions was HCl-P > NaOH-P > BD-P > NH4Cl-P. The loosely sorbed phosphorus (NH4Cl-P) represented < 1% of the sedimentary inorganic phosphorus, while the reductant phosphorus (BD-P) ranged 5-6%. The calcium bound phosphorus (HCl-P) showed considerable contribution (59-74%) to the sedimentary inorganic P-loads. The metal oxide bound phosphorus (NaOH-P) was higher in the hypertrophic (30-35%) than in the meso-to-eutrophic system (19-28%). Fine-sized sediments exhibited significantly higher concentrations of HCl-P in Volvi and NH4Cl-P in Koronia. Sampling month had significant effect in variance of most P-fractions and other sediment features in both lakes. Use was also made of multivariate statistics to identify the factors which influence the sedimentary phosphorus. NaOH-P was the most reactive fraction in Lake Volvi. Iron compounds and organic matter seem to play a significant role in regulating this labile P-budget. NH4Cl-P was the more reactive fraction in Lake Koronia which was influenced by sedimentation of P-absorbed on clay/silt fine particles.

Calcium↗