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PubMed2002

Impact of four years exposure to different levels of ozone, phosphorus and drought on chlorophyll, mineral nutrients, and stem volume of Norway spruce, Picea abies.

Saplings of one clone of Norway spruce, Picea abies (L.) Karst, were planted in 120 l pots in 1991 and exposed to three levels of ozone, two levels of phosphorus and two levels of water supply in 42 open-top chambers (OTCs), during 1992-1996. The effects of pots and OTCs were also tested. Nutrient concentrations of the needles were not affected by ozone, while the low phosphorus supply (LP) and drought stress (D) treatments had significant effects on several mineral nutrients, e.g. phosphorus, calcium, magnesium, manganese, sulphur and boron. Ozone reduced the chlorophyll concentration in the 2- and 3-year-old needles in 1994 and 1995. The highest ozone concentration reduced the stem volumes (- 8%), as well as the stem lengths (- 5%), of the saplings in 1993 and 1994, after two and three years of exposure. After the fourth growing season this ozone-induced reduction in stem volume disappeared which might be caused by pot limitation. LP supply and D both caused large decreases in the stem volume and length. The needles from LP treatment had as high P concentration as 1.2-1.5 mg g-1, implying a need for increasing the critical value for phosphorus. The OTC enclosure stimulated the stem volume growth significantly compared to saplings growing in ambient plots. This was suggested to be attributed to the slightly higher temperature in the OTCs. The overall result is that ozone in southern Sweden is likely to have negative effects on Norway spruce trees, although much less than other environmental factors, e.g. water and phosphorus.

Journal Article↗
PubMed2004

Structure and bonding in the isoelectronic series CnHnP5-n+: is phosphorus a carbon copy?

The relative stabilities of different isomers of the isoelectronic series C(n)H(n)P(5-n)(+) have been investigated using G3X theory. The results indicate that all species containing one or more phosphorus atom adopt a three-dimensional nido geometry, in marked contrast to the planar structure favoured by the all-carbon analogue. Within isomeric nido clusters, a strong correlation between total energy and the nucleus-independent chemical shift (NICS) indicates that three-dimensional aromaticity plays a significant role in determining the stability of the cluster. In the context of these nido clusters, the extent to which phosphorus is a carbon copy proves to be highly dependent on the global electronic environment. The first isolobal substitution of CH by P causes a complete switch from localised to delocalised bonding, accompanied by a transition from a two- to a three-dimensional structure, with the phosphorus atom showing a strong preference for the unique apical site. In contrast, further increasing the phosphorus content causes no further change in structure or bonding, suggesting that, at the basal sites, phosphorus is a rather better carbon copy. The low-energy pathways for interconversion of apical and basal atoms previously identified in C(2)H(2)P(3)(+) prove to be a general feature of all members of the series.

Journal Article↗
PubMed2003

The purification and characterization of phosphonopyruvate hydrolase, a novel carbon-phosphorus bond cleavage enzyme from Variovorax sp Pal2.

Phosphonopyruvate hydrolase, a novel bacterial carbon-phosphorus bond cleavage enzyme, was purified to homogeneity by a series of chromatographic steps from cell extracts of a newly isolated environmental strain of Variovorax sp. Pal2. The enzyme was inducible in the presence of phosphonoalanine or phosphonopyruvate; unusually, its expression was independent of the phosphate status of the cell. The native enzyme had a molecular mass of 63 kDa with a subunit mass of 31.2 kDa. Activity of purified phosphonopyruvate hydrolase was Co2+-dependent and showed a pH optimum of 6.7-7.0. The enzyme had a Km of 0.53 mm for its sole substrate, phosphonopyruvate, and was inhibited by the analogues phosphonoformic acid, 3-phosphonopropionic acid, and hydroxymethylphosphonic acid. The nucleotide sequence of the phosphonopyruvate hydrolase structural gene indicated that it is a member of the phosphoenolpyruvate phosphomutase/isocitrate lyase superfamily with 41% identity at the amino acid level to the carbon-to-phosphorus bond-forming enzyme phosphoenolpyruvate phosphomutase from Tetrahymena pyriformis. Thus its apparently ancient evolutionary origins differ from those of each of the two carbon-phosphorus hydrolases that have been reported previously; phosphonoacetaldehyde hydrolase is a member of the haloacetate dehalogenase family, whereas phosphonoacetate hydrolase belongs to the alkaline phosphatase superfamily of zinc-dependent hydrolases. Phosphonopyruvate hydrolase is likely to be of considerable significance in global phosphorus cycling, because phosphonopyruvate is known to be a key intermediate in the formation of all naturally occurring compounds that contain the carbon-phosphorus bond.

Amino Acid Sequence↗
PubMed1980

Phosphorus nutrition and fasting: interrelated factors which affect the survival of young chickens exposed to high ambient temperature.

The interaction of phosphorus nutrition and fasting on the tolerance of young chickens acutely exposed to high temperature was studied. We also investigated a possible relationship between plasma phosphate (Pi) and body temperature (Tr) of chicks during heat exposure. Survival time (ST) of 24-hour fasted (F-24) chicks previously fed a low-phosphorus diet (LP) was markedly lower than ST of F-24 chicks fed an adequate phosphorus diet (AP). Diet, however, had no effect on ST of chicks fasted 12 hours (F-12). The apparent metabolic responses of F-24 chicks were qualitatively different than those of F-12 chicks suggesting that the effect of previous phosphorus nutrition was dependent on metabolic status of chicks before heat exposure. The concentration of Pi during heat exposure of F-24 chicks fed the experimental diets was highly (P less than 0.001) correlated with Tr. At heat-induced exhaustion, Tr of chicks fed either diet was not different. Pi of these groups at this point was nearly identical despite marked differences in the time at which this event occurred. An investigation concerning a possible relationship between Pi and the respiratory failure known to occur in hyperthermic chickens, revealed that respiratory muscular fatigue is not the primal cause of respiratory failure. Our results demonstrated that phosphorus nutrition, Pi and metabolic status are dependent factors related to the tolerance of young chickens exposed to high temperature.

Animals↗
PubMed1989

Leaf phosphorus and nitrogen concentrations and net photosynthesis in Eucalyptus seedlings.

Seedlings of Eucalyptus grandis Hill ex Maiden, E. pilularis Smith and E. gummifera (Sol. ex Gaertner) Hochr. were grown in solution culture with 100 micromol phosphorus (P). After eight weeks, half of the seedlings were transferred to solution cultures containing 1 micromol P. After a further four weeks, growth, net photosynthesis and foliar P and nitrogen (N) concentrations were measured. The seeds of E. grandis came from a relatively fertile site and those of the other two species from phosphorus-deficient sites. Growth and net photosynthesis did not change in E. pilularis subjected to the low-P treatment, whereas in E. grandis, and to a limited extent in E. gummifera, the low-P treatment resulted in an increase in net photosynthesis that was associated with higher foliar N concentrations (especially protein-N), possibly as a result of nitrogen being retranslocated from the roots. In response to the low-P treatment, leaf phosphorus concentration was reduced by 50-60% in E. grandis and E. pilularis and by 20-30% in E. gummifera. Of the chemical fractions examined, the greatest decrease occurred in the inorganic-P pool. The data suggest that photosynthesis is not limited by leaf phosphorus concentrations typical of those found in Eucalyptus seedlings growing on phosphorus-deficient sites.

Journal Article↗
PubMed1972

Turnover of Phospholipids in Normal and Phosphorus-deficient Spirodela.

When (32)P(1) was supplied as a 15-minute pulse to normal Spirodela oligorrhiza plants, the first phospholipid to become fully labeled was phosphatidic acid. Phosphatidyl glycerol reached maximum labeling before the other major phospholipids. In phosphorus-deficient plants, however, phosphatidyl glycerol became labeled much more slowly than either phosphatidyl choline or phosphatidyl ethanolamine, and also the proportion of phosphatidyl glycerol present was smaller. Thus, phosphatidyl glycerol synthesis is sensitive to phosphorus deficiency. Since most of the phosphatidyl glycerol present in Spirodela was localized in the chloroplast, this effect appeared to be specifically one on chloroplast composition. The phosphorus-deficient chloroplast had a 60% lower phospholipid content and a normal phospholipid pattern, but the phospholipid which was present was apparently cycling much less rapidly. Zeatin, which ameliorates the visual symptoms of phosphorus deficiency, also reduces the effect of phosphorus deficiency on phospholipid synthesis.

Journal Article↗
PubMed1986

Increased Arginine Biosynthesis during Phosphorus Deficiency : A Response to the Increased Ammonia Content of Leaves.

The accumulation of arginine in leaves of four citrus rootstock cultivars during P deficiency has been demonstrated to be due to increased de novo synthesis rather than decreased catabolism or increased protein degradation (E Rabe, CJ Lovatt, 1984, Plant Physiol 76: 747-752). In this report, we provide evidence (a) that the increased activity of the arginine biosynthetic pathway observed for citrus rootstocks grown under P-deficient conditions for 7 months is due to an increase in the concentration of ammonia in leaves of P-deficient plants and (b) that ammonia accumulation and removal through arginine systhesis are early responses to phosphorus deficiency for both a woody perennial, rough lemon (Citrus limon), and an herbaceous annual, summer squash (Cucurbita pepo). Transferring 5-day-old squash plants to a phosphorus-deficient nutrient solution for only 10 days resulted in a 2-fold increase in the concentration of nitrate in the youngest fully expanded leaves (YFE). Concomitantly, the specific activity of nitrate reductase doubled and the ammonia content of P-deficient YFE leaves increased to a concentration significantly greater that of leaves from healthy control plants (P < 0.05). Consistent with increased availability of ammonia, the incorporation of NaH(14)CO(3) into arginine plus urea doubled during phosphorus deficiency and arginine accumulated. Despite the accumulation of nitrate and ammonia in YFE leaves during phosphorus deficiency, the total nitrogen content of these leaves was less than that of the healthy control plants. Similar results were obtained for rough lemon. Nitrate content of the YFE leaves increased 1.5- and 3.0-fold in plants deprived of phosphorus for 6 and 12 weeks, respectively. Ammonia content of the leaves increased as P deficiency progressed to 1.4 +/- 0.08 mg (+/- se, n = 4) per gram dry weight, a level 1.8-fold greater than that of the P-sufficient control plants. During P deficiency de novo arginine biosynthesis in rough lemon increased 10-fold. Immersing the petiole of YFE leaves from P-sufficient squash and rough lemon plants in 50 millimolar NH(4) (+) for 3 hours resulted in the accumulation of ammonia in the leaves, and a 4-fold increase in the incorporation of NaH(14)CO(3) into arginine plus urea. Taken together, these results provide strong evidence that the accumulation of nitrate and ammonia in leaves is an early response of both woody and herbaceous plants to P deprivation. The data are consistent with the hypothesis that increased de novo arginine biosynthesis in leaves during P deficiency is in response to ammonia content of the leaves.

Journal Article↗
PubMed1988

Aluminum Effects on Uptake and Metabolism of Phosphorus by the Cyanobacterium Anabaena cylindrica.

Aluminum severely affects the growth of the cyanobacterium Anabaena cylindrica and induces symptoms indicating phosphorus starvation. Preor post-treating the cells with high (90 micromolar) phosphorus reduces the toxicity of aluminum compared to cells receiving a lower orthophosphate concentration. In this study aluminum (ranging from 9 to 36 micromolar) and phosphorus concentrations were chosen so that the precipitation of insoluble AIPO(4) never exceeded 10% of the total phosphate concentration. The uptake of (32)P-phosphorus is not disturbed by aluminum either at high (100 micromolar) or low (10 micromolar) concentrations of phosphate. Also, the rapid accumulation of polyphosphate granules in cells exposed to aluminum indicates that the incorporation of phosphate is not disturbed. However, a significant decrease in the mobilization of the polyphosphates is observed, as is a lowered activity of the enzyme acid phosphatase, in aluminum treated cells. We conclude that aluminum acts on the intracellular metabolism of phosphate, which eventually leads to phosphorus starvation rather than on its uptake in the cyanobacterium A. cylindrica.

Journal Article↗
PubMed1992

Release of bacterial DNA by marine nanoflagellates, an intermediate step in phosphorus regeneration.

The concentrations of dissolved DNA and nanoflagellates were found to covary during a study of diel dynamics of the microbial food web in the Adriatic Sea. This observation was further investigated in a continuous seawater culture when nanoflagellates were fed bacteria grown in filtered seawater. Analysis of dissolved organic phosphorus and dissolved DNA showed a sixfold increase of dissolved DNA in the presence of the nanoflagellates (Ochromonas sp.). The amount of DNA released suggested that the majority of the consumed bacterial DNA was ejected. Phagotrophic nanoflagellates thus represent an important source of origin for dissolved DNA. The rate of breakdown of dissolved DNA and release of inorganic phosphorus in the pelagic ecosystem is suggested to be dependent on the ambient phosphate pool. In the P-limited northern Adriatic Sea, rapid degradation of the labelled DNA could be demonstrated, whereas the N-limited southern California bight water showed a much lower rate. Phosphorus originating from dissolved DNA was shown to be transferred mainly to organisms in the <3-mum-size fractions. On the basis of the C/P ratios, we suggest that a significant fraction of the phosphorus demand by the autotrophs may be sustained by the released DNA during stratified conditions. Thus, the nucleic acid-rich bacterial biomass grazed by protozoa plays an important role in the biogeochemical cycling of phosphorus in the marine environment.

Journal Article↗
PubMed1976

Effects of phosphorus supplementation on serum parathyroid hormone and bone morphology in osteoporosis.

The effect of phosphorus (inorganic phosphate) supplementation was studied in seven postmenopausal women with osteoporosis. Prior to supplementation, all chemical parameters studied in serum and urine were normal. Bone density was below the fifth percentile for age in all but one patient, and the percentage of bone surface involved in resorption was higher than normal. During administration of the phosphorus supplement, fasting serum concentrations of calcium and immunoreactive parathyroid hormone showed no significant changes, while serum phosphorus, urinary calcium, and tubular reabsorption of phosphorus decreased. In four patients studied by balance techniques, calcium balance became positive or less negative. Bone-forming surface decreased and bone-resorbing surface increased in all patients. Bone-resorbing surface was highly correlated with total phosphorus intake. Density of the distal radius changed variably, while density of the midradius increased slightly in all patients.

Aged↗
PubMed1994

Laying hens respond differently to high dietary levels of phosphorus in monobasic and dibasic calcium phosphate.

A series of experiments were conducted to determine the relative acidogenicities of dietary chloride, phosphorus, and sulfate and their effects on shell quality. Calcium salts of these anions were added to a corn-soybean meal diet to provide supplemental levels of 150 to 450 meq/kg diet chloride, 150 to 600 meq/kg diet monobasic phosphate, 150 to 1,200 meq/kg diet dibasic phosphate, and 150 to 1,200 meq/kg diet sulfate. The results indicated that laying hens can safely tolerate up to 200 meq/kg diet supplemental chloride (.95% total chloride in the diet) and up to 450 to 600 meq/kg diet supplemental sulfate (2.16 to 2.88% added sulfate). Levels higher than these adversely affected shell quality and altered blood acid-base balance. Laying hens responded quite differently to phosphorus when it was supplied as monobasic or dibasic phosphate. Supplemental levels of 900 to 1,200 meq/kg diet dibasic phosphate (1.95 to 2.41% total phosphorus) did not have an adverse effect on performance and up to a supplemental level of 450 meq/kg diet (1.25% total phosphorus) did not affect shell quality. In contrast, performance was seriously impaired by a supplemental level of 150 meq/kg diet monobasic phosphate (1.02% total phosphorus in the diet). The results further indicated that phosphate in monobasic (but not in dibasic) form is a strong acidogenic anion and that most of its adverse effect on performance and shell quality can be ameliorated by alkaline salts of sodium or potassium bicarbonate. The relative acidogenicities of calcium salts of these acidic anions were as follows: phosphate (monobasic) > chloride > sulfate > phosphate (dibasic).

Acid-Base Equilibrium↗
PubMed2001

[Epidemiological features about serum phosphorus level in renal failure].

Before a renal failure patient begins dialysis therapy, the serum creatinine concentration becomes high and at the same time the serum phosphorus level is also on the rise. In a dialysis patient, on the other hand, the serum phosphorus concentration decreases with age. Also, among those on dialysis, a patient with elevated intact-PTH and one with a high normalized protein catabolic rate (nPCR) show virtually no relation of a high serum phosphorus level with either the serum calcium level or the serum phosphorus level. The phosphorous concentration in a hemodialysis patient is linked to the prognosis, and there is a high mortality risk in a patient with a pre-dialysis serum phosphorus level of less than 3.0 mg/dl or 7.0 mg/dl or more.

English Abstract↗
PubMed1989

Circadian rhythms for calcium, inorganic phosphorus, and parathyroid hormone in primary hyperparathyroidism: functional and practical considerations.

We obtained serial serum and urine samples from 14 patients with primary hyperparathyroidism both before and 3 to 9 months after excision of their parathyroid adenomas to (1) determine whether the circadian rhythms for calcium, phosphorus, and parathyroid hormone (PTH) previously described in normal human beings are disturbed in this disorder; (2) gauge the effect of surgical treatment on the patterns observed before intervention; and (3) ascertain whether time(s) of blood sampling can be defined for optimal biochemical detection of the disease. Significant rhythms for serum phosphorus, ionized calcium, PTH, urine phosphorus, and urine calcium were observed in many but not all patients before and after surgery. Nonetheless, collective analysis revealed the following: (1) diurnal patterns for serum ionized calcium, phosphorus, urine calcium, and urine phosphorus in patients with primary hyperparathyroidism both before and after surgery, whereas a rhythm for serum PTH was uniquely observed after surgical treatment; and (2) no significant correlation between preoperative serum ionized calcium and PTH but restoration of the expected reciprocal relationship between these variables after surgery. Although variability in individual expression of the rhythm for PTH precludes precise definition of a sampling "window" when hormone levels are likely to be highest, collection of data at points throughout the day helped establish the diagnosis of primary hyperparathyroidism in several patients with borderline serum biochemistries.

Adenoma↗
PubMed1986

Uric acid and phosphorus excretion in dogs with lymphosarcoma.

Serum uric acid and phosphorus concentrations were determined for 27 dogs with multicentric lymphosarcoma before and after chemotherapy. Mean serum uric acid values in dogs before treatment were significantly higher (P less than 0.05) than those of a control group of healthy dogs. Serum uric acid values did not change after treatment. Of the 27 dogs, 13 had 24-hour urine collections to determine endogenous creatinine clearance and quantitation of uric acid and phosphorus excretion before and after treatment for lymphosarcoma. Mean values for 24-hour creatinine clearance before and after treatment were statistically similar in dogs with lymphosarcoma, although the values were lower than those in a normal range. Total urinary phosphorus excretions were increased significantly (P less than 0.01) after treatment without change in fractional excretion. Chemotherapeutic agents used accounted for the significant (P less than 0.05) increase in urine volume after treatment and may have affected the excretion of uric acid and phosphorus. Seemingly, dogs with uncomplicated lymphosarcoma rarely have renal dysfunction or clinically important alterations in uric acid or phosphorus excretion secondary to rapid tumor lysis. However, preexisting renal disease or systemic complications, such as hypercalcemia, may be associated with increased risk of further renal impairment during treatment.

Animals↗
PubMed1983

Disorders of calcium and phosphorus metabolism after successful kidney transplantation.

Systematic study undertaken of 44 transplant patients with plasma creatinine below 0.11 mmol/L indicated renal phosphorus leak in approximately two-thirds of them and increased plasma PTH in all but one. Plasma 1,25(OH)2D was elevated in half the patients in whom it was measured. The lack of correlation found between plasma 1,25(OH)2D and plasma PTH or phosphorus probably indicates tubular lesions resulting in decreased production of 1,25(OH)2D. A phosphorus restriction test in 12 hypophosphatemic patients demonstrated that the reduced renal phosphorus reabsorption probably was due to both persisting hyperparathyroidism and a PTH-independent phosphorus leak.

Adolescent↗
PubMed1997

Preparation of radiotherapy glass by phosphorus ion implantation at 100 keV.

A chemically durable glass containing a large amount of phosphorus is useful for in situ irradiation of cancers. It can be activated to be a beta emitter (half-life of 14.3 days) by neutron bombardment. Microspheres of the activated glass injected into the tumors can irradiate the tumors directly with beta rays without irradiating neighboring normal tissues. In the present study a P+ ion was implanted into a pure silica glass in a plate form at 100 keV in order to find the fundamental conditions for obtaining such a glass. Little phosphorus was present in the surface region, at least to a depth of 2.4 nm for doses of 5 x 10(16) and 1 x 10(17) cm-2, whereas an appreciable amount of it was distributed on the glass surface and a part of it was oxidized for doses above 5 x 10(17) cm-2. The glasses implanted with doses of 5 x 10(16) and 1 x 10(17) cm-2 hardly released the P and Si into water at 95 degrees C, even after 7 days, whereas the glasses implanted with doses above 5 x 10(17) cm-2 released appreciable amounts of these elements. Implantation energies of 20 and 50 keV (even at doses of 5 x 10(16) and 1 x 10(17) cm-2, respectively), formed oxidized phosphorus on the glass surfaces and gave appreciable release of the P and Si into the hot water. This indicates that a chemically durable glass containing a larger amount of phosphorus could be obtained if a P+ ion is implanted at higher energies to localize in a deeper region of the glass surface.

Biocompatible Materials↗
PubMed1995

Sequential correlation of anomeric ribose protons and intervening phosphorus in RNA oligonucleotides by a 1H, 13C, 31P triple resonance experiment: HCP-CCH-TOCSY.

A three-dimensional 1H, 13C, 31P triple resonance experiment, HCP-CCH-TOCSY, is presented which provides unambiguous through-bond correlation of all 1H ribose protons on the 5' and 3' sides of the intervening phosphorus along the backbone bonding network in 13C-labeled RNA oligonucleotides. The correlation of the complete ribose spin system to the intervening phosphorus is obtained by adding a C,C-TOCSY coherence transfer step to the triple resonance HCP experiment. The C,C-TOCSY transfer step, which utilizes the large and relatively uniform 1J(C,C) coupling constant (approximately 40 Hz for ribose carbons), efficiently correlates the phosphorus-coupled carbons observed in the HCP correlation experiment (i.e., C4' and C5' in the 5' direction and C4' and C3' in the 3' direction) to all other carbons in the ribose spin system. Of the additional correlations observed in the HCP-CCH-TOCSY, that to the relatively well-resolved anomeric H1',C1' resonance pairs provides the greatest gain in terms of facilitating assignment. The gain in spectral resolution afforded by chemical shift labeling with the anomeric resonances should provide a more robust pathway for sequential assignment over the intervening phosphorus in larger RNA oligonucleotides. The HCP-CCH-TOCSY experiment is demonstrated on a uniformly 13C, 15N-labeled 19-nucleotide RNA stem-loop, derived from the antisense RNA I molecule found in the ColE1 plasmid replication control system.

Base Sequence↗
PubMed1994

Interaction of vanadium and phosphorus in chicks.

Studies were carried out to determine the effect of dietary vanadium on chicks fed phosphorus deficient and control diets. Vanadium at 50 mg/kg of diet decreased growth of both control and deficient chicks. The high mortality among the phosphorus deficient chicks was significantly alleviated by the presence of vanadium. The increased relative ventricular weights found among the deficient chicks was also alleviated by the presence of dietary vanadium. Vanadium fed at 10 or 20 mg/kg diet did not reduce growth rate but significantly reduced mortality among chicks fed the deficient diet and decreased the relative ventricle weights. Time course studies revealed that chicks are hatched with high relative ventricular weights (.83% of body wt) and remain at that level among chicks fed the phosphorus deficient diet. The addition of vanadium or phosphate to the diet resulted in a progressive decrease in relative ventricular weights. The inclusion of vanadium in the diet resulted in increased serum phosphorus levels among the deficient chicks that may be related to the decrease in mortality and relative ventricle weights.

Animals↗