Changes in phosphorus composition of Candida utilis during the cell cycle and postcycle period

1971 ◽  
Vol 17 (3) ◽  
pp. 339-345 ◽  
Author(s):  
H. Glättli ◽  
P. S. S. Dawson
Keyword(s):  
Cell Cycle ◽  
Candida Utilis ◽  
Phosphorus Content ◽  
Cold Water ◽  
Carbon Limitation ◽  
Cycle Period ◽  
Phosphorus Fraction ◽  
Extractable P ◽  
Rna And Dna ◽  
Water Extractable

Cells of Candida utilis were grown under carbon limitation in phased culture at a doubling time of 4 h. The phosphorus contents of four (lipid, cold water extractable, RNA, and DNA) fractions, obtained empirically by serial extraction of the cells, were determined at [Formula: see text]-h intervals during the cell cycle and post-cycle periods. The results showed that the phosphorus composition of the cells was changing throughout both cell cycle and postcycle periods.Each phosphorus fraction doubled during the cell cycle; for the major fractions (cold water extractable P and RNA-P) this occurred as a gradual increase spread over the cell cycle period, but for the minor fractions (lipid-P and DNA-P) the increase was restricted to the latter half of the cell cycle period. Expressed as proportions of the total phosphorus content, the phosphorus contents of the major fractions remained constant, but the minor ones changed during the cell cycle. Other, different, changes were observed between the various fractions during the postcycle period.

Changing patterns of 32P and 33P utilization in cells of Candida utilis during the cell cycle

1972 ◽  
Vol 18 (11) ◽  
pp. 1691-1693 ◽  
Author(s):  
P. S. S. Dawson ◽  
H. Glättli
Keyword(s):  
Cell Cycle ◽  
Doubling Time ◽  
Candida Utilis ◽  
Cold Water ◽  
Growth Conditions ◽  
Changing Patterns ◽  
Rna And Dna ◽  
Synchronized Cultures ◽  
In Cells

Incorporation of 33P and 32P into different fractions of continuous phased (synchronized) cultures of Candida utilis was studied. Two different growth conditions (on C-limited and N-limited media) were used at a doubling time of 6 h. Incorporation of 33P and 32P into four fractions (lipid, cold-water ex-tractable, RNA and DNA) showed a variable, nonuniform, behavior during the cell cycle. Different patterns of incorporation between cells on the two media were observed.

Leaching of dissolved phosphorus from tile-drained agricultural areas

2016 ◽  
Vol 73 (12) ◽  
pp. 2953-2958 ◽  
Author(s):  
H. E. Andersen ◽  
J. Windolf ◽  
B. Kronvang
Keyword(s):  
Soil Layer ◽  
High Concentration ◽  
Measured Concentration ◽  
Leaching Potential ◽  
Dissolved Phosphorus ◽  
Olsen P ◽  
P Loss ◽  
Tile Drains ◽  
Extractable P ◽  
Water Extractable

Abstract We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss.

Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Bielinski M. Santos ◽  
Joan A. Dusky ◽  
William M. Stall ◽  
Donn G. Shilling ◽  
Thomas A. Bewick
Keyword(s):  
Competitive Ability ◽  
Organic Soils ◽  
Weed Species ◽  
Population Densities ◽  
Replacement Series ◽  
Amaranthus Hybridus ◽  
Extractable P ◽  
Common Purslane ◽  
Smooth Pigweed ◽  
Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

A laboratory study of phosphorus mobilisation from commercial fertilisers

Soil Research ◽  
2003 ◽  
Vol 41 (6) ◽  
pp. 1201 ◽  
Author(s):  
D. Nash ◽  
M. Hannah ◽  
L. Clemow ◽  
D. Halliwell ◽  
B. Webb ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Total Variation ◽  
Laboratory Study ◽  
High Moisture ◽  
Single Superphosphate ◽  
South Eastern ◽  
Extractable P ◽  
Eastern Australia ◽  
Water Extractable ◽  
South Eastern Australia

Phosphorus (P) exported from pastures following fertiliser application contributes to the nutrients and associated problems in the streams and rivers of south-eastern Australia. This laboratory study examined whether attributes of P fertilisers may affect P exports soon after their application to field soils; 3 commercial fertilisers [diammonium phosphate (DAP), single superphosphate (SSP), and sulfur-coated single superphosphate (CSSP)] were applied to 2 repacked soils (Arawata and Ellinbank) at 5 moisture contents.Soil type was the most important factor affecting water-extractable P (expressed as a percentage of the P added as fertiliser), accounting for 30% of the total variation. The majority of this variation is explained by the water-extractable P concentrations in the Arawata low moisture treatments. These treatments [7, 6, and 6% soil moisture when equilibrated at 99, 95, and 86.5% relative humidity (RH), respectively] contained water-extractable P concentrations c. 3 times higher than the high moisture (c. 20 and 25% soil moisture) or the Ellinbank treatments. This result probably reflects differences in soil properties including the extent of water repellency and P adsorption.Fertiliser type explained only 6.9% (P < 0.001) of the total variation in water-extractable P, partially as a result of the 86.5% RH (a low moisture) Arawata treatment. In this Arawata low moisture treatment, the mean extractable P was similar for both DAP and SSP, 13.1% [least significant interval (l.s.i.) 16.7–10.3] and 11.3% (l.s.i. 14.3–8.9), respectively, but for SSP, water-extractable P increased over time unlike any other treatment. Water-extractable P from DAP was approximately double that from SSP for the Ellinbank and high moisture treatments. The higher water-extractable P following DAP application is explained in terms of its chemical properties and reaction products. Sulfur coating the SSP granules (CSSP) increased water-extractable P, as did higher soil moisture.This study suggests that under conditions present in most pastures in south-eastern Australia and depending on soil hydrology, water-extractable P and P export from fertilisers may increase in the order DAP > CSSP > SSP if overland flow occurs soon after their application.

A comparison of some surface soil phosphorus tests that could be used to assess P export potential

Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  
Keyword(s):  
Organic P ◽  
Soil Tests ◽  
Soil P ◽  
Olsen P ◽  
P Sorption ◽  
P Loss ◽  
Extractable P ◽  
Soil P Tests ◽  
Total P ◽  
Water Extractable

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.

Stimulation by pH of cell cycle initiation in the yeast Candida utilis

1981 ◽  
Vol 59 (11) ◽  
pp. 2043-2048 ◽  
Author(s):  
K. Chandapillai Thomas
Keyword(s):  
Cell Cycle ◽  
Nitrogen Source ◽  
Growth Medium ◽  
Respiratory Quotient ◽  
Doubling Time ◽  
Candida Utilis ◽  
Cellular Processes ◽  
Ph Shift ◽  
Bud Emergence ◽  
Limiting Nutrient

The effect of shifting pH of the growth medium on cell cycle initiation by the yeast Candida utilis was studied. The yeast was grown by the phased method of cultivation with nitrogen source (ammonium) in growth limiting concentrations and with a phasing period (imposed doubling time) of 6 h. The pH of the culture during the phased growth was maintained between 2.0 and 2.1. The rate of cell cycle initiation as determined by the rate of bud emergence was 24% per hour. If the pH of the culture was shifted to 6.0 at the beginning of the phasing period and maintained at that level for the rest of the phasing period the rate of bud emergence increased to 50% per hour. The increased rate of bud emergence was accompanied by a fast uptake of oxygen and the growth-limiting nutrient and by a reduction in the respiratory quotient. The results suggest that the pH shift accelerated cellular processes necessary for cell cycle initiation.

scholarly journals Chemical, morphological, rheological and thermal properties of Solanum lycocarpum phosphorylated starches

Revista CERES ◽  
2014 ◽  
Vol 61 (4) ◽  
pp. 458-466 ◽  
Author(s):  
Diego Palmiro Ramirez Ascheri ◽  
Luciane Dias Pereira ◽  
Suely Miranda Cavalcante Bastos
Keyword(s):  
Phosphorus Content ◽  
Cold Water ◽  
Sodium Tripolyphosphate ◽  
Raw Materials ◽  
Principal Component ◽  
Physicochemical Characteristics ◽  
Native Starch ◽  
Modified Starches ◽  
Pasting Temperature ◽  
Water Swelling

The increasing need for starches with specific characteristics makes it important to study unconventional starches and their modifications in order to meet consumer demands. The aim of this work was to study physicochemical characteristics of native starch and phosphate starch of S. lycocarpum. Native starch was phosphated with sodium tripolyphosphate (5-11%) added with stirring. Chemical composition, morphology, density, binding ability to cold water, swelling power and solubility index, turbidity and syneresis, rheological and calorimetric properties were determined. Phosphorus was not detected in the native sample, but the phosphating process produced modified starches with phosphorus contents of 0.015, 0.092 and 0.397%, with the capacity of absorbing more water, either cold or hot. Rheological data showed the strong influence of phosphorus content on viscosity of phosphate starch, with lower pasting temperature and peak viscosity higher than those of native starch. Enthalpy was negatively correlated with the phosphorus content, requiring 9.7; 8.5; 8.1 and 6.4 kJ g-1 of energy for the transition from the amorphous to the crystalline state for the starch granules with phosphorus contents of 0; 0.015; 0.092 and 0.397%, respectively. Cluster analysis and principal component analysis showed that starches with 0.015 and 0.092% phosphorus have similar characteristics and are different from the others. Our results show that the characteristics of phosphate modified S. lycocarpum starch have optimal conditions to meet the demands of raw materials, which require greater consistency in stickiness, combined with low rates of retrogradation and syneresis.

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