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Solution conformations, and substrate/inhibitor properties towards several phosphodiesterases and other nucleolytic enzymes, have been investigated for the cyclic phosphates of various acyclonucleosides, some with known antiviral activity, including 9-[(l,3-dihydroxy-2-propoxy)methyl]guanine (DHPG) and its carbocyclic congener, 9-(3,4-dihydroxybutyl)guanine (DHBG), 9-[4-hydroxy-2-(hydroxymethyl)- butyl]-guanine (2HM-HBG), and 9-(2,3-dihydroxypropyl)guanine (HPG). Conformations of the cyclic phosphate rings were derived from analysis of the 1H-1H and 1H-31P vicinal coupling constants in the n.m.r. spectra, subsequently optimalized by minimalization of the internal energy. The resulting structures were examined with respect to their ability to recognize various specific phosphodiesterases and nucleases, and some structural parameters were delineated for acyclonucleotide interactions. Qualitative data are presented for inhibitory properties of the acyclonucleoside cyclic phosphates, and, in those instances where they were substrates, kinetic constants were evaluated. An unusual finding was the apparent ability of nuclease P1 to hydrolyse a five-membered cyclic phosphate ring of an acyclonucleoside.
The substratum photomorphogenesis — the increase of dry weight in light as compared with darkness — takes place only on the nutrient solution with yeast extract. On a synthetic medium with the phosphate level varying from 2.87 to 22.96 mM, the dry weight of mycelia is the same in light and in darkness. In a similar way the phosphorus content in the mycelia and the amount of this element taken up are not related to light conditions. The organism utilizes about 66% of the phosphate present in the nutrient solution.
A considerable number of bacterial species are able to exert a beneficial effect upon plant growth. Mostly they are associated with the plant rhizosphere, so they are called as rhizobacteria. Phosphorus is an essential element for plant development and growth making up about 0.2 % of plant dry weight. Several scientists have reported the ability of different bacterial species to solubilize insoluble inorganic phosphate compounds, such as tricalcium phosphate, dicalcium phosphate, hydroxyapatite, and rock phosphate. Detection and estimation of the phosphate solublization ability of microorganisms have been possible using plate screening methods. Phosphate solubilizers produce clearing zones around the microbial colonies in growth media. In the present investigation a total number of fifteen phosphate solubilizing bacterial colonies isolated from different paddy soils in Cuddalore district of Tamilnadu, India. The isolated PSB were identified and characterized for effective use in the field. All the PSB isolates were identified as Bacillus species and designated as P with serial number from 1 to 15. Among the fifteen isolates, the PSB isolate P6 showed highest amount of phosphate solubilization. The quantity of available phosphorus estimated in the P6 grown Sperber broth culture medium on 7th day was maximum of 321.7 μg/ml which was the highest value compared to other PSB isolates.
 Aim: Active vitamin D (1,25-dihydroxyvitamin D3), PTH, fibroblast growth factor-23 (FGF-23) and Klotho protein are key regulators of phosphate metabolism. Hyperphosphatemia and increased FGF-23 level in patients with end-stage renal disease are associated with increased morbidity and mortality. The relationships among key regulators of phosphate metabolism are still being investigated. FGF-23, the humoral factor involved in phosphate metabolism, is strongly associated with serum phosphorus level. Klotho, a transmembrane protein expressed primarily in renal tubules, functions as an obligatory co-receptor for FGF-23. The soluble form of Klotho, produced by the shedding of the transmembrane protein, is detectable in body fluids. The purpose of the study was to assess if serum soluble alpha-Klotho level was related to phosphate metabolism parameters and residual renal function (RRF) in incident peritoneal dialysis (PD) patients. Methods: Thirty-five clinically stable patients 4 to 6 weeks after the onset of PD were included in the study. For each patient, clinical and laboratory data were reviewed. Serum phosphorus concentration, urinary and peritoneal phosphate clearance, serum FGF-23 and soluble Klotho protein concentrations were determined. Results: Serum soluble alpha-Klotho was strongly negatively correlated with 24-hour diuresis (Rs = -0.55, p = 0.004) and renal phosphate clearance (Rs = -0.40, p = 0.049), but not with RRF. Conclusions: Serum soluble Klotho protein concentration is inversely related to residual diuresis and renal phosphate clearance in incident PD patients.
From the early 60's till the late 80's, in many countries - among them also in Hungary - agricultural production went through a tremendous development. In Hungary there was a 2-3-fold increase in the average yields of winter wheat, and maize - the two main crops - in comparison to those of the 50's. One of the main factors determining these developments was the increasing use of mineral fertilizers. From the turn of the century till the late 50's, nutrient balances in Hungary were strongly negative: 20 - 30 kg/ha/year less N and K₂O, and 10 kg/ha/year less P₂O₅ was given to the fields in the different forms (farmyard manure, mineral fertilizer and by-products, etc.), than was removed by the harvested yields. Nutrient balances of P became positive in the early 60's, while balances of N and K in the early 70's, resp. Then, for 20 years, N balances were positive by 10 - 20 kg/ha/year, while both P₂O₅ and K₂O balances by 30 - 50 kg/ha/year, resp. These long-term positive nutrient balances resulted in the NPK enrichment of our soils, which was also proven by the national soil test series. During the 80's, for example, the amount of yearly applied mineral fertilizer was 230 - 280 kg/ha N + P₂O₅ + K₂O/arable land. In certain regions N leaching could cause environmental damage, while, as a result of the P-Zn antagonism, on the fields poorly supplied with Zn, overfertilization with P resulted in 1 - 2 t/ha/year maize yield losses. From the early 90's, however, when political and ecological changes took place in the country, the free market was introduced, and state subsidies on mineral fertilizer were withdrawn, there was a sharp decrease in mineral fertilizer use: applied N dropped to 1/5th, P and K to 1/20th of the amount used in the 80's. This dramatic decrease resulted in the change of nutrient balances: in 1991 the balance for N was -60, for P₂O₅ -30, and for K₂O -40 kg/ha for the whole country, resp. In 1992 and 1993 the situation was similar, while in 1994 a slight increase in mineral fertilizer use was observed. According to our estimation, mineral fertilization of 150 kg/ha/year N + P₂O₅ + K₂O is sufficient for long-term sustainable plant nutrition in Hungary, if farmyard manure application and the incorporation of byproducts remains on the recent level. During intensive fertilization practice, emphasis was on the quantity, while crop and soil demands for specific or more economic fertilizers were not taken into consideration. For N, lime ammonium nitrate, for P superphosphate, and for K, potash chloride was used on almost the whole area. As a new attempt to find more economic P sources, Algerian rock phosphate was checked in field trials, set up on characteristic acidic soils in different regions of Hungary, as well as other Central European countries. The first two-year results are discussed in the presentation.
The effect of addition of wheat cellulose preparation on the quality and structure of finely ground model products was tested. Apart from potassium tripolyphosphate, the wheat cellulose preparation WF-400 was added to the stuffing, at different levels of addition of technological water: 30, 50 and 80%. The testing of the model processed meat products covered: determination of heat leakage, evaluation of the basic composition in the preserved product block according to the relevant PN ISO standards, quality and profile sensory evaluation, analysis of texture profile and tensile strength of slices with the universal machine Zwick model 1445. The values of the evaluated parameters of texture profile and quality and sensorial profile of model products were substantially affected by the level of addition of technological water. The higher level of water addition substantially lowered the values of the tested parameters. The preparation of tripolyphosphate as well as tripolyphosphate and cellulose effectively reduced cooking losses and they had a structure-creating action, the cellulose preparation “strengthened” the action of phosphates. In result of the trial the use of cellulose preparation as a functional additive and/or with potassium tripolyphosphate to finely ground meat products was found reasonable and, in particular, to the products of different level of addition of technological water.
The paper dealt with the evaluation of concentration and spatial distribution of nitrogen and phosphorus forms in dug wells in selected farms in the upper Narew River valley. The study was also aimed at assessing the influence of selected elements of a farm on quality of well water. Examinations were carried out in 8 villages in Podlasie region. Three farm dug wells were selected for examination in each village. All wells take water from the first water-carrying level. The study included well waters within the section of the Narew River from the villages Sobótka to Złotoria. The checkpoints were set in: Sobótka, Narew, Ciełuszki, Kaniuki, Zawyki, Uhowo, Topilec, and Złotoria localized along the Narew and its adjacent lands. Water samples were collected in spring, summer and autumn 2006. Ammonia, nitrates (III), nitrates (V), and phosphates were determined in water samples filtered through micropore filters (d = 0.45 μm) by means of colorimetry applying a spectrometer HACH (DR-2000). Parameters of the analytical procedures were adjusted in accordance to the Decree of Minister for Environment (2004). In total, 288 determinations in three series were made. For each of the three wells from every village, the arithmetic means of the analyzed parameters were calculated on the basis of samples collected on three dates. The assessment of underground water quality was made according to the Decree of Minister for Environment of 11 February 2004 on on surface and underground water status, screening performance, interpretation and presentation of the status of such waters. In addition, the Decree of the Minister for Health of 29 March 2007 (Rozporządzenie Ministra Zdrowia, 2007) was referred to. The results were compared to concentrations of forms of particular components (N-NH4, N-NO2, N-NO3) included in the Decree of the Minister for Environment (2004) and the Decree of the Minister for Health (2007) in order to designate water quality classes and principal chemical requirements to the well waters examined. The study revealed that the analyzed waters did not meet standards set for potable water due to exceeding permissible values for ammonia and nitrates (V) concentrations. The distance of a well from the nearest farm buildings affected ammonia concentration in well water.
The object of this study was to determine change of natural buffer capacity of humic acids by strong buffering agents, which were phosphate ions. Studies were carried out on the humic acids extracted from peat soils. Additional information was obtained by determination of water holding capacity, density, ash and pH for peats and optical parameterQ4/6 for humic acids. Humic acid suspensions exhibited the highest buffer properties at low pH and reached maximum at pH ~ 4. Phosphates possessed buffer properties in the pH range from 4.5 to 8.0. The maximum of buffering was at pH~6.8 and increased proportionally with an increase in the concentration of phosphate ions. The study indicated that the presence of phosphate ions may strongly change natural buffer capacity of humic acids by shifting buffering maximum toward higher pH values. Significant correlations were found for the degree of the secondary transformation with both the buffer capacity and the titrant volume used during titration.
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