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PubMed2004

[Influence of long-term fertilization on phosphorus fertility of calcareous soil I. Organic matter, total phosphorus and available phosphorus].

A 23 years-located experiment of wheat-corn rotation showed that long term application of animal manure combined with chemical fertilizer contributed greater to the contents of soil organic matter, total phosphorus, inorganic phosphorus and available phosphorus. Applying chemical fertilizer could increase soil organic matter, total phosphorus, inorganic phosphorus and available phosphorus contents, but the increment was lower than treatments animal manure and fallow. Compared with no fertilization, different fertilization treatment had its own distribution characteristics of soil organic matter, total phosphorus and available phosphorus in 0-100 cm soil layer.

Biomass↗
PubMed1982

Production of pesticide metabolites by oxidative reactions.

The cytochrome P-450-dependent monooxygenase system catalyzes a wide variety of oxidations of pesticide chemicals and related compounds. These reactions include epoxidation and aromatic hydroxylation, aliphatic hydroxylation, O-, N- and S-dealkylation, N-oxidation, oxidative deamination, S-oxidation, P-oxidation, desulfuration and ester cleavage and may result in either detoxication or activation of the pesticide. The current status of such reactions, relative to the production, in vivo, of biologically active intermediates in pesticide metabolism is summarized. More recently we have shown that the FAD-containing monooxygenase of mammalian liver (E.C.1.14.13.8), a xenobiotic metabolizing enzyme of broad specificity formerly known as an amine oxidase, is involved in a variety of pesticide oxidations. These include sulfoxidation of organophosphorus insecticides such as phorate and disulfoton, oxidative desulfuration of phosphonate insecticides such as fonofos and oxidation at the phosphorus atom in such compounds as the cotton defoliant, folex. The relative importance of the FAD-containing monooxygenase vis-a-vis the cytochrome P-450-dependent monooxygenase system is discussed, based on in vitro studies on purified enzymes.

Animals↗
PubMed2002

The gas-phase acidity of HCP, CH3CP, HCAs, and CH3CAs: an unexpected enhanced acidity of the methyl group.

The gas-phase acidities of methylidynephosphine, HCtbond;P, ethylidynephosphine, CH(3)Ctbond;P, and ethylidynearsine, CH(3)Ctbond;As, have been measured by means of Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometry and calculated at the CCSD(T)/6-311+G(3df,2p)//QCISD/ 6-311+G(df,p) level of theory. An analysis of these results shows that, in contrast to the well-known fact that HCtbond;N is a stronger acid than CH(3)Ctbond;N, CH(3)Ctbond;P and CH(3)Ctbond;As are more acidic than HCtbond;P and HCtbond;As, respectively. The most important consequence of this unexpected effect is that while HCtbond;P and HCtbond;As are found to be weaker acids than HCtbond;N, the opposite trend is found for the corresponding methyl derivatives, the acidity of which increases as CH(3)Ctbond;N<CH(3)Ctbond;P<CH(3)Ctbond;As. Also the effects of deprotonation on the structures and the vibrational frequencies of HCtbond;X and CH(3)Ctbond;X (X=N, P, As) compounds are qualitatively similar, but quantitatively very different for nitrogen- as compared with phosphorus- and arsenic-containing compounds. A rationalization of these differences in terms of the bonding differences is presented.

Journal Article↗
PubMed1993

Preventive effect of beta-alanyl-L-histidinato zinc on the deterioration of bone metabolism in ovariectomized rats.

The preventive effect of beta-alanyl-L-histidinato zinc (AHZ) on the deterioration of bone metabolism was investigated in the femoral diaphysis of ovariectomized rats. AHZ (10, 30 and 100 mg/kg body weight/d) was orally administered to ovariectomized rats for 6 weeks. Ovariectomy produced a significant decrease in estradiol, calcitonin, calcium and inorganic phosphorus concentrations in the serum as compared with those from sham-operated rats. The dose of 30 and 100 mg AHZ/kg prevented any decrease in serum inorganic phosphorus concentration caused by ovariectomy. Alkaline phosphatase activity, deoxyribonucleic acid (DNA) and calcium contents in the femoral diaphysis of ovariectomized rats significantly decreased in comparison with those from sham-operated rats. These decreases were completely prevented by the dose of AHZ (10, 30 and 100 mg/kg). Electron microscopical analysis showed a rough alteration of bone matrix in the femoral diaphysis of ovariectomized rats. This alteration was clearly modified by the doses of AHZ (10, 30 and 100 mg/kg). Also, dosages of AHZ (30 and 100 mg/kg) restored the atrophy of osteoblasts and cartilage cells caused by ovariectomy. The present study suggests that oral administration of AHZ can prevent the deterioration of bone metabolism by ovariectomy. AHZ may have a therapeutic role in the treatment of osteoporosis.

Alkaline Phosphatase↗
PubMed2001

Phosphorus removal from a real anaerobic supernatant by struvite crystallization.

In this paper the phosphorus removal from a real anaerobic supernatant through the crystallization of struvite and or hydroxyapatite was investigated. A comparison between experimental results on phosphorus crystallization carried out in a fluidized-bed reactor (FBR) on a bench-scale and on a half-scale plant is presented, together with a double saturational model able to describe all experimental results, independent of the different geometry of the reactors, the distinct contact times and the unlike products obtained. Experimental results show that removal efficiencies are very satisfactory, and the maximum phosphorus removal is of 80%.

Anaerobiosis↗
PubMed2001

Purification and characterization of a novel phosphorus-oxidizing enzyme from Pseudomonas stutzeri WM88.

The ptxD gene from Pseudomonas stutzeri WM88 encoding the novel phosphorus oxidizing enzyme NAD:phosphite oxidoreductase (trivial name phosphite dehydrogenase, PtxD) was cloned into an expression vector and overproduced in Escherichia coli. The heterologously produced enzyme is indistinguishable from the native enzyme based on mass spectrometry, amino-terminal sequencing, and specific activity analyses. Recombinant PtxD was purified to homogeneity via a two-step affinity protocol and characterized. The enzyme stoichiometrically produces NADH and phosphate from NAD and phosphite. The reverse reaction was not observed. Gel filtration analysis of the purified protein is consistent with PtxD acting as a homodimer. PtxD has a high affinity for its substrates with Km values of 53.1 +/- 6.7 microm and 54.6 +/- 6.7 microm, for phosphite and NAD, respectively. Vmax and kcat were determined to be 12.2 +/- 0.3 micromol x min(-1) x mg(-1) and 440 min(-1). NADP can substitute poorly for NAD; however, none of the numerous compounds examined were able to substitute for phosphite. Initial rate studies in the absence or presence of products and in the presence of the dead end inhibitor sulfite are most consistent with a sequential ordered mechanism for the PtxD reaction, with NAD binding first and NADH being released last. Amino acid sequence comparisons place PtxD as a new member of the d-2-hydroxyacid NAD-dependent dehydrogenases, the only one to have an inorganic substrate. To our knowledge, this is the first detailed biochemical study on an enzyme capable of direct oxidation of a reduced phosphorus compound.

Chromatography, Gel↗
PubMed1985

Changes in brain phosphorus metabolites during the post-natal development of the rat.

Changes in brain phosphorus metabolites during the post-natal development of the rat and in neonatal and adult guinea-pigs have been studied in vivo using 31P nuclear magnetic resonance spectroscopy (n.m.r.s.). The brain spectra showed clear differences with age, particularly during the first 3 weeks post-partum. The spectra from 4-day-old rats resembled those of new-born human infants. We suggest that the differences between human and animal brains seen in previously published spectra arise because of an age difference rather than a species difference. The phosphocreatine (PCr) to nucleoside triphosphate (NTP) ratio increased from around 1.0 in 3-day-old rats to 1.8 in adult animals. The adult ratio is larger than that previously reported from in vitro chemical analyses. An unknown compound in the phosphomonoester (PME) region of the spectra predominated in young animals, but decreased in concentration relative to NTP with age and reached adult values by around 2 weeks post-partum. Neonatal guinea-pigs, which are much more developed at birth than the rat, had a significantly greater PCr/NTP ratio than the neonatal rat, but their brain spectra also contained the large PME peak. The intracellular pH of cerebral tissue was estimated to be 7.21 +/- 0.02 and did not show any change with age. The changes we find in the phosphorus compounds in the brain may be of importance in post-natal development, and the possible functional significance of these results is discussed.

Adenosine Triphosphate↗
PubMed2026

Isolation and genomic characterization of Bacillus X32: a potent phosphate-solubilizing bacterium with growth-promoting effects on navel orange seedlings.

Phosphorus is an essential element for plant growth. However, in nature, most phosphorus exists in the form of insoluble compounds that plants cannot directly absorb, leading to phosphorus deficiency in agricultural systems. With increasing demand for economic crops such as citrus and the decline in soil fertility due to current management practices, there is a growing need for environmentally friendly fertilizers to improve and restore soil conditions. In this study, a highly efficient phosphate&#x2011;solubilizing strain X32 was isolated from the rhizosphere soil of Gannan navel oranges. Systematic genomic analysis identified it as a putative novel species within the genus Bacillus, showing the closest phylogenetic relationship to Bacillus spizizenii. However, both the average nucleotide identity (ANI&#x2009;=&#x2009;93.18%) and digital DNA&#x2011;DNA hybridization (dDDH&#x2009;=&#x2009;50.4%) values fell below the established thresholds for species delineation, indicating significant genomic differentiation. Whole&#x2011;genome sequencing further revealed that strain X32 harbors multiple functional genes potentially related to phosphorus metabolism, including inorganic phosphate&#x2011;solubilizing genes (e.g., gdh and gltA), phosphate transport genes (e.g., glpT, pstA, pstB, pstC), and phosphorus mineralization genes (e.g., phoA, phoD). Pot experiment results demonstrated that inoculation with strain X32 significantly promoted the growth of navel orange seedlings, as evidenced by marked increases in both aboveground and belowground fresh and dry weights, as well as plant height. Additionally, strain X32 significantly enhanced the activities of antioxidant enzymes (SOD, CAT, POD) and regulated the content of chlorophyll b in seedling leaves, these changes suggest that strain X32 may enhance stress resistance in plants and influence photosynthetic pigment composition, though direct measurements of photosynthetic performance are needed for confirmation. This study provides a theoretical basis for developing microbial fertilizers with efficient phosphorus solubilization and plant growth-promoting functions, which may help reduce dependence on phosphorus fertilizers and promote sustainable agricultural development.

Phosphates↗
PubMed1990

Synthesis and antitumor activity of 1-[[(dialkylamino)alkyl]amino]-4-methyl-5H-pyrido[4,3-b]benzo[e]- and -benzo[g])indoles. A new class of antineoplastic agents.

The thermal Fischer indolization of hydrazones resulting from 4-hydrazino-5-methyl-1H-pyridin-2-one and various beta- and alpha-tetralones led to 4-methyl-6,7-dihydro-2H,5H-pyrido[4,3- b]benzo[e]indol-1-ones and 4-methyl-11-dihydro-2H,5H-pyrido[4,3- b]benzo[g]indol-1-ones, respectively. After aromatization, these compounds were transformed by phosphorus oxychloride, giving 1-chloro-4-methyl-5H-pyrido[4,3- b]benzo[e]- and -benzo[g]indoles which were substituted by [(dialkylamino)alkyl]amines. The resulting 1-[[(dialkylamino)alkyl]amino]-4-methyl-5H-pyrido- [4,3-b]benzo[e]- and -benzo[g]indoles, as well as hydroxy derivatives obtained by demethylation of methoxylated compounds with hydrobromic acid, were tested for antitumor activity in vitro (leukemic and solid tumor cells) and in vivo on various experimental tumor models using the standard NCI protocols. 1-[[3-(Dialkylamino)propyl]-amino]-4-methyl-9-hydroxy-5H-pyrido[4,3- b]benzo[e]indoles appeared as a promising new class of antineoplastic agents.

Animals↗
PubMed1975

Effect of hydrochlorothiazide on phosphorus during treatment with diphosphonate.

The effects of probenecid and hydrochlorothiazide on renal handling of phosphorus during hyperphosphatemia induced by diphosphonate (ethane-1-hydroxy-1, 1-diphosphonate, EHDP) was studied. Measurements of calcium, phosphorus, and creatinine clearance were performed in 2 sessions on each of 3 consecutive days in 10 normal fasting volunteers during the morning hours from 8 A.M. to 12 noon. During 2 to 3 wk thereafter, each subject was treated with EHDP, 30 mg/kg/day. The second group of studies were performed in the same manner as the first except the EHDP administration was continued throughout. EHDP caused elevation of serum phosphorus in all cases. Probenecid did not affect urine phosphorus. Hydrochlorothiazide caused a transient phosphaturia of similar magnitude in the EHDP treated and untreated states. Creatinine clearance was not affected by any of the treatments and urine calcium was decreased by EHDP. It was concluded that hydrochlorothiazide inhibits tubular reabsorption of phosphorus but that it does not affect the mechanism whereby EHDP causes increased tubular reabsorption of phosphorus. Chronic administration of hydrochlorothiazide along with EHDP may inhibit hyperphosphatemia and may change the bone effects of EHDP.

Adult↗