Adequate Amounts Of Phosphorus Research Articles

Enhancing lipid production in microalgae Chlorella PY-ZU1 with phosphorus excess and nitrogen starvation under 15% CO2 in a continuous two-step cultivation process

To promote biomass and lipid productivity of microalgae in a continuous two-stage cultivation process with 15% CO2, adequate phosphorus was supplemented in the second stage of cultivation involving nitrogen starvation and stored with regulated existence patterns to improve the metabolic activity of Chlorella PY-ZU1. The results showed that the applied strategy allowed microalgae biomass concentration and lipid productivity 1.3 and 2.2 times higher, respectively, than those without phosphorus supplementation. Chlorella PY-ZU1 cells cultivated with an adequate amount of phosphorus were analyzed by electron microscopy that revealed the distribution of polyphosphates in the cytoplasm, vacuoles, and along the cell membranes. P-31 nuclear magnetic resonance (31P NMR) showed polyphosphate, pyrophosphate, and orthophosphate contents of 0.59, 2.46, and 8.21 mg g−1, respectively, in the extracts of Chlorella PY-ZU1 cells obtained by the NaOH-EDTA method. Moreover, the ATP synthase involved in the photosynthesis and oxidative phosphorylation pathways was up-regulated to promote biomass productivity, while the enzymes involved in carbon fixation and glycerolipid metabolism were up-regulated to facilitate lipid accumulation in cells.

Tomato fertigation with dairy cattle wastewater

ABSTRACT The use of wastewater in the fertigation of agricultural crops increases productivity and product quality, and contributes to reduce environmental pollution. In this work, the objective was to evaluate how the use of dairy cattle wastewater (DCWW) in the fertigation of tomatoes affected production and productivity, as well as foliar nutritional contents, in an organic farming system. Treatments consisted of six nitrogen doses (0, 50, 100, 200, 300 and 400%), having N recommendation for tomato (100 kg/ha) as reference, applied using DCWW via fertigation. DCWW is made up of washing water, urine, feces and milk. Stem diameter, branch length, weekly fruit yield per plant and aggregate productivity were evaluated. N, P, K, Ca, Mg, S, Cu, Mn, Fe, Zn and B foliar contents were quantified. Data were submitted to analysis of variance (p≤0.05) and, where significant, polynomial regression models were applied. Treatment means were compared by the Tukey test (p≤0.05). The highest production, productivity and nutrient foliar accumulation were observed when 400% of the N dose recommended for tomato was used. There was an increasing linear effect on weekly and aggregate yield and also on nutrient accumulation in leaves as function of the applied N dose. N fertilization in tomato organic production can be carried out using DCWW via fertigation, but with a complementary mineral fertilization to supply plants with adequate amounts of phosphorus and potassium.

Comparison of Microbial Phytase and Dicalcium Phosphate for Growth and Bone Mineralization of Pond-Raised Channel Catfish, Ictalurus punctatus

This study evaluated the use of microbial phytase as replacement for inorganic phosphorus supplement in diets for pond-raised channel catfish, Ictalurus punctatus. Channel catfish fingerlings (average weight: 23 g) were stocked into twelve 0.04-ha ponds at a rate of 18,525 fish/ha. Four ponds were used for each treatment. Fish were fed one of three experimental diets containing 250 or 500 FTU (phytase unit) phytase/kg, or 0.75% dicalcium phosphate once daily to satiation from May to October, 2000. No differences were observed in diet consumption, weight gain, feed conversion ratio, survival, or bone ash and phosphorus concentrations among fish fed different diets. Based on these results it appears that a phytase concentration of 250 FTU/kg diet applied post-pelleting can replace the dicalcium phosphate supplement in channel catfish diets without affecting fish growth and bone mineralization under pond culture conditions. We recommend that a phytase level of 500 FTU/kg diet be used and that the diet contain a total phosphorus level of 0.6% or above to ensure that adequate amount of phosphorus is available to channel catfish. Based on current prices of phytase and inorganic phosphorus sources, it is economical to use phytase in catfish diets.

Removal of Phosphorus by Peritoneal Dialysis

Substantial evidence exists that peritoneal dialysis, as currently practiced, cannot alone remove adequate amounts of phosphorus in well-nourished patients. Current efforts should address the possibility of developing improved nontoxic oral phosphorus binders and/or different compositions of dialysate fluid.

BIOLOGICAL AND AGRONOMIC ASPECTS OF LEGUME INOCULATION IN ISRAEL

Inoculants prepared for farm use consist of cultures of rhizobial strains selected for their invasiveness and effectivity in greenhouse and field trials. The acetylene reduction assay, hemoglobin content of nodules and plant nitrogen content were used for evaluation of nitrogen fixation intensity. An autoclaved local enriched peat constituted a very suitable substrate for all fast-growing rhizobia, but was often toxic to slow-growing ones. This was overcome by culturing the slow-growing rhizobia together with fast-growing (non-infective), slime-producing bacteria. Chemically treated and fragile seeds, e.g. common bean or peanut, were inoculated by applying the bacterial suspension directly into the planting furrows. For soils not bearing local specific rhizobia, relatively small amounts of inoculant (100–500 g/ha) were sufficient for adequate nodulation. However, to overcome competition of native rhizobial population, it was often necessary to use greatly increased amounts of inoculant. The effect of irrigation regimes commonly used in Israel on success of inoculation, rate of nodulation, and plant vegetative and reproductive development was investigated. In nitrogen-poor soils, symbiotic nitrogen fixation could not only substitute for mineral nitrogen, but even provide higher yields than nitrogen fertilization. A high content of available soil nitrogen may lead to serious difficulties in legume inoculation practice. Ways of overcoming these difficulties were examined. In certain soils fertilization with adequate amounts of phosphorus was found to be a prerequisite for proper nodulation and symbiotic nitrogen fixation. In calcareous and alkaline soils, application of iron chelate was necessary for N 2 fixation to occur.

Experimental Hyperparathyroidism in Young Cats

Hyperparathyroidism was produced experimentally in 23 rapidly growing kittens with an immature skeleton by feeding a diet of beef heart and distilled water. The experimental diet was deficient in calcium but contained an adequate amount of phosphorus. Weekly serum analyses revealed a significant hypocalcemia after feeding the diet for 3 weeks. The parathyroid glands of experimental cats were hyperplastic and were dominated by hypertrophied light chief cells. There was a generalized decrease in density of the bones roentgenographically by the 3rd week with a loss of fine trabeculation and thinning of bone cortices in the appendicular skeleton. Clinical signs were first observed at 4 weeks. The cats developed a posterior lameness, were quiet and reluctant to move. The skeletal lesions of increased osteocytic and osteoclastic resorption, osteoblastic apposition, diminished mineral content, and replacement of resorbed bone by fibrous connective tissue were considered to be a morphologic reflection of increased secretion of parathyroid hormone. The osteitis fibrosa produced in kittens differed from the osteoporosis reported in adult cats with a mature skeleton fed a similar diet.

The tubular reabsorption of phosphate in the differential diagnosis of metabolic bone disease.

ABSTRACT The percentage of filtered phosphorus that is reabsorbed by the renal tubules (TRP) was measured in normal subjects and in patients suspected of having metabolic bone disease. When dietary intake of phosphorus before the test was not controlled, the TRP ranged between 77 and 93 per cent in normal subjects and patients without demonstrable disturbances of calcium and phosphorus metabolism. No correlation could be established between the serum phosphorus concentration and the TRP. If the diet contained adequate amounts of phosphorus, the TRP was low in all of the cases of primary hyperparathyroidism that were studied; after phosphorus deprivation, the TRP was often in the normal range. These observations are considered to be consistent with the view that parathyroid hormone lowers the maximal tubular capacity for phosphate reabsorption. The TRP was consistently low in patients with malignant neoplasms complicated by hypercalcemia. The chief usefulness of the TRP test in clinical diagnosis lies in t...

The effect of a vitamin D-free fat on the absorption and retention of phosphorus

A vitamin D-free fat, namely, purified cottonseed oil, incorporated in an adequate-calcium, low-phosphorus, cereal-free rachitogenic ration, when fed to young rats increased the absorption and retention of phosphorus but decreased the percentage of bone ash. This apparently was caused by an increase in growth which made the demand for phosphorus of certain soft tissues dominant over those of bone. When fat was fed with the basal ration supplemented with an adequate amount of phosphorus, the demand of both types of tissue could be met; calcification of bone was increased and the phosphorus content of certain soft tissues such as the liver was also increased. It follows, that data on calcification of bone cannot always be used as a criterion of the over-all state of phosphorus equilibrium in the animal.

RELATION OF CALCIUM, PHOSPHORUS AND NITROGEN RETENTION TO GROWTH AND OSSEOUS DEVELOPMENT

The reports on the amount of the three metabolites—calcium, phosphorus and nitrogen—needed by children of a given age have varied, because, it is believed, there were differences in the growth pattern of the children studied, in the degree of saturation of the tissues at the time of the study and in the availability of the metabolites in the materials fed. Furthermore, the retention of calcium and nitrogen is influenced not only by the amount needed but by whether an adequate amount of phosphorus is supplied by the diet. In many of the studies only calcium balances were reported; comparisons, therefore, may not be valid. The problem is further confused by the fact that many of the studies have been of short duration. Continuous balance studies both with children and with adults have indicated that there is considerable variation from period to period; and although this is due in part to

Relation of Milk Ingestion to Calcium Metabolism in Children

Calcium, phosphorus and nitrogen retention studies comprising 46 metabolism periods with 8 children between 3 and 5 years of age lead to the conclusion that a pint of milk, furnishing 75% of the calcium, when included as part of a diet containing adequate amounts of phosphorus, protein, fat and vitamins from other sources will supply enough calcium to meet the needs of normal children of the ages considered. The conclusions are based on a comparison of the retentions of these essential growth constituents when the children were taking diets containing a pint and a quart of milk respectively. In one series of tests the children received cod liver oil; in a second, cod liver oil and Viosterol; and in a third during June and July they were given no cod liver oil, but spent a large part of the day out of doors. The average retentions following the various diet modifications are given in the table.Seemingly the difference in the amount of calcium retained by children receiving different levels of milk above a ...