Accumulation and phosphatase-lability of organic phosphorus in fertilised pasture soils

2007 ◽  
Vol 58 (1) ◽  
pp. 47 ◽  
Author(s):  
Timothy S. George ◽  
Richard J. Simpson ◽  
Paul A. Hadobas ◽  
David J. Marshall ◽  
Alan E. Richardson
Keyword(s):  
Organic Phosphorus ◽  
Trifolium Subterraneum ◽  
Organic P ◽  
Wild Type ◽  
P Nutrition ◽  
P Content ◽  
Extracellular Phytase ◽  
Fertiliser Application ◽  
And Control ◽  
Water Extractable

The accumulation and phosphatase-lability of organic P was investigated in soil taken from 3 pastures that had received contrasting fertiliser management over 8 years. The soils were either unfertilised or had received superphosphate either from 1994 to 1997 or applied annually to 2002. P-fertilisation led to an increase in both the inorganic and organic P content of the soils, but with differences in the distribution of organic P in various extractable pools. Fertilisation also affected the amount of organic P that was amenable to hydrolysis by a non-specific phosphatase. In particular, the amount of water-extractable organic P that was phosphatase-labile was greatest in soil that had received continuous fertiliser application. Despite improved phosphatase-lability of different organic P pools in the fertilised soils, transgenic Trifolium subterraneum L., which releases extracellular phytase, showed no consistent advantage in growth and P nutrition compared with either wild-type or azygous controls when grown in intact cores of soil. This indicates that organic P that accumulates with P-fertilisation is either not an effective substrate for transgenic plants that exude phytase or is equally available to transgenic and control plants.

THE DISTRIBUTION OF ORGANIC PHOSPHORUS IN BRITISH COLUMBIA SOILS AND ITS RELATIONSHIP TO SOIL CHARACTERISTICS

1965 ◽  
Vol 45 (1) ◽  
pp. 87-95 ◽  
Author(s):  
M. K. John ◽  
P. N. Sprout ◽  
C. C. Kelley
Keyword(s):  
Organic Phosphorus ◽  
Chemical Properties ◽  
The Other ◽  
Organic P ◽  
Significant Relationships ◽  
P Content ◽  
Wide Range ◽  
Relationship Of ◽  
The Relationship ◽  
Total P

The relationship of organic phosphorus content to a number of chemical properties was studied in the surface horizons of 38 soils of six different soil orders in British Columbia.The concentration of organic P ranged from 1.8 to 77.7% of the total P with amounts varying from 21 to 802 p.p.m. The forested soils of the Podzolic and Brunisolic Orders contained the least organic P. However, the wide range in organic P content within some soil orders indicated that its distribution was not entirely characteristic of the soil order.Simple correlation studies between organic P and nitrogen, carbon, pH, per cent base saturation, total P, and free iron in all soils before assigning them to groups indicated that only nitrogen and carbon were significantly related to organic P. Significant relationships between the other variables and organic P were restricted to specific soil orders. The organic P content has been found to be primarily dependent on nitrogen and pH, since the inclusion of the other independent variables in the multiple regression did not significantly change the coefficient of determination.The range of C/organic P and N/organic P ratios for the 38 samples was between 46 and 648 and 5.5 to 57.6 respectively. Soil pH was the only variable studied which could account for the wide variation of these ratios.

Limitations to the Potential of Transgenic Trifolium subterraneum L. Plants that Exude Phytase when Grown in Soils with a Range of Organic P Content

2005 ◽  
Vol 278 (1-2) ◽  
pp. 263-274 ◽  
Author(s):  
Timothy S. George ◽  
Alan E. Richardson ◽  
J. Barry Smith ◽  
Paul A. Hadobas ◽  
Richard J. Simpson
Keyword(s):  
Trifolium Subterraneum ◽  
Organic P ◽  
P Content

scholarly journals Richness of Rhizosphere Organisms Affects Plant P Nutrition According to P Source and Mobility

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 157
Author(s):  
Jean Trap ◽  
Patricia Mahafaka Ranoarisoa ◽  
Usman Irshad ◽  
Claude Plassard
Keyword(s):  
Careful Consideration ◽  
Soil Conditions ◽  
Organic P ◽  
P Nutrition ◽  
Soil P ◽  
P Acquisition ◽  
Complex Interactions ◽  
Experimental Trials ◽  
The Relationship

Plants evolve complex interactions with diverse soil mutualist organisms to enhance P mobilization from the soil. These strategies are particularly important when P is poorly available. It is still unclear how the soil P source (e.g., mineral P versus recalcitrant organic P) and its mobility in the soil (high or low) affect soil mutualist biological (ectomycorrhizal fungi, bacteria and bacterial-feeding nematodes) richness—plant P acquisition relationships. Using a set of six microcosm experiments conducted in growth chamber across contrasting P situations, we tested the hypothesis that the relationship between the increasing addition of soil mutualist organisms in the rhizosphere of the plant and plant P acquisition depends on P source and mobility. The highest correlation (R2 = 0.70) between plant P acquisition with soil rhizosphere biological richness was found in a high P-sorbing soil amended with an organic P source. In the five other situations, the relationships became significant either in soil conditions, with or without mineral P addition, or when the P source was supplied as organic P in the absence of soil, although with a low correlation coefficient (0.09 < R2 < 0.15). We thus encourage the systematic and careful consideration of the form and mobility of P in the experimental trials that aim to assess the role of biological complexity on plant P nutrition.

Selected Contribution: Differential role of nitric oxide synthase isoforms in fever of different etiologies: studies using Nosgene-deficient mice

2003 ◽  
Vol 94 (6) ◽  
pp. 2534-2544 ◽  
Author(s):  
Wieslaw Kozak ◽  
Anna Kozak
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Corn Oil ◽  
Normal Male ◽  
Wild Type ◽  
Oxide Synthase ◽  
And Control ◽  
Nos Isoforms ◽  
Deficient Mice

Male C57BL/6J mice deficient in nitric oxide synthase (NOS) genes (knockout) and control (wild-type) mice were implanted intra-abdominally with battery-operated miniature biotelemeters (model VMFH MiniMitter, Sunriver, OR) to monitor changes in body temperature. Intravenous injection of lipopolysaccharide (LPS; 50 μg/kg) was used to trigger fever in response to systemic inflammation in mice. To induce a febrile response to localized inflammation, the mice were injected subcutaneously with pure turpentine oil (30 μl/animal) into the left hindlimb. Oral administration (gavage) of N G-monomethyl-l-arginine (l-NMMA) for 3 days (80 mg · kg−1 · day−1in corn oil) before injection of pyrogens was used to inhibit all three NOSs ( N G-monomethyl-d-arginine acetate salt and corn oil were used as control). In normal male C57BL/6J mice, l-NMMA inhibited the LPS-induced fever by ∼60%, whereas it augmented fever by ∼65% in mice injected with turpentine. Challenging the respective NOS knockout mice with LPS and with l-NMMA revealed that inducible NOS and neuronal NOS isoforms are responsible for the induction of fever to LPS, whereas endothelial NOS (eNOS) is not involved. In contrast, none of the NOS isoforms appeared to trigger fever to turpentine. Inhibition of eNOS, however, exacerbates fever in mice treated with l-NMMA and turpentine, indicating that eNOS participates in the antipyretic mechanism. These data support the hypothesis that nitric oxide is a regulator of fever. Its action differs, however, depending on the pyrogen used and the NOS isoform.

scholarly journals The kfrA gene is the first in a tricistronic operon required for survival of IncP-1 plasmid R751

Microbiology ◽  
2006 ◽  
Vol 152 (6) ◽  
pp. 1621-1637 ◽  
Author(s):  
Malgorzata Adamczyk ◽  
Patrycja Dolowy ◽  
Michal Jonczyk ◽  
Christopher M. Thomas ◽  
Grazyna Jagura-Burdzy
Keyword(s):  
Coiled Coil ◽  
Broad Host Range ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Wild Type ◽  
C Terminus ◽  
Low Copy Number ◽  
And Control ◽  
Broad Host Range Plasmids

The kfrA gene of the IncP-1 broad-host-range plasmids is the best-studied member of a growing gene family that shows strong linkage to the minimal replicon of many low-copy-number plasmids. KfrA is a DNA binding protein with a long, alpha-helical, coiled-coil tail. Studying IncP-1β plasmid R751, evidence is presented that kfrA and its downstream genes upf54.8 and upf54.4 were organized in a tricistronic operon (renamed here kfrA kfrB kfrC), expressed from autoregulated kfrAp, that was also repressed by KorA and KorB. KfrA, KfrB and KfrC interacted and may have formed a multi-protein complex. Inactivation of either kfrA or kfrB in R751 resulted in long-term accumulation of plasmid-negative bacteria, whereas wild-type R751 itself persisted without selection. Immunofluorescence studies showed that KfrAR751 formed plasmid-associated foci, and deletion of the C terminus of KfrA caused plasmid R751ΔC 2 kfrA foci to disperse and mislocalize. Thus, the KfrABC complex may be an important component in the organization and control of the plasmid clusters that seem to form the segregating unit in bacterial cells. The studied operon is therefore part of the set of functions needed for R751 to function as an efficient vehicle for maintenance and spread of genes in Gram-negative bacteria.

scholarly journals Downregulation of CD40L–CD40 attenuates seizure susceptibility and severity of seizures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esther Pototskiy ◽  
Katherine Vinokuroff ◽  
Andrew Ojeda ◽  
C. Kendall Major ◽  
Deepak Sharma ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Molecular Techniques ◽  
Seizure Susceptibility ◽  
Wild Type ◽  
Upward Trend ◽  
Seizure Severity ◽  
Cd40 Expression ◽  
Neuro Inflammation ◽  
And Control ◽  
Deficient Mice

AbstractUnregulated neuro-inflammation mediates seizures in temporal lobe epilepsy (TLE). Our aim was to determine the effect of CD40–CD40L activation in experimental seizures. CD40 deficient mice (CD40KO) and control mice (wild type, WT) received pentenyltetrazole (PTZ) or pilocarpine to evaluate seizures and status epilepticus (SE) respectively. In mice, anti-CD40L antibody was administered intranasally before PTZ. Brain samples from human TLE and post-seizure mice were processed to determine CD40–CD40L expression using histological and molecular techniques. CD40 expression was higher in hippocampus from human TLE and in cortical neurons and hippocampal neural terminals after experimental seizures. CD40–CD40L levels increased after seizures in the hippocampus and in the cortex. After SE, CD40L/CD40 levels increased in cortex and showed an upward trend in the hippocampus. CD40KO mice demonstrated reduction in seizure severity and in latency compared to WT mice. Anti-CD40L antibody limited seizure susceptibility and seizure severity. CD40L–CD40 interaction can serve as a target for an immuno-therapy for TLE.

Abstract 9: Involvement of Caveolin-1 in Vascular Remodeling and Inflammation Induced by Angiotensin II

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Steven J Forrester ◽  
Tatsuo Kawai ◽  
Katherine J Elliott ◽  
Takashi Obama ◽  
Takehiko Takayanagi ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Vascular Remodeling ◽  
Egf Receptor ◽  
Critical Role ◽  
Membrane Microdomains ◽  
Structural Protein ◽  
Wild Type ◽  
Caveolin 1 ◽  
Medial Hypertrophy ◽  
And Control

We have recently reported that caveolin-1 (Cav1) enriched membrane microdomains in vascular smooth muscle cells (VSMC) mediate a metalloprotease ADAM17-dependent EGF receptor (EGFR) transactivation, which is linked to vascular remodeling induced by AngII. We have tested our hypothesis that Cav1, a major structural protein of caveolae, plays a critical role for development of vascular remodeling by AngII via regulation of ADAM17 and EGFR. Here, 8 week old male Cav1-/- and control Cav+/+ wild-type mice (WT) were infused with AngII (1 μg/kg/min) for 2 weeks to induce vascular remodeling and hypertension. Upon AngII infusion, histological assessments demonstrated medial hypertrophy and perivascular fibrosis of coronary and renal arteries in WT mice compared with saline-infused control mice. The AngII-infused WT mice also showed a phenotype of cardiac hypertrophy with increased HW/BW ratio (mg/g: 8.0±0.6 vs 5.7±0.7 p<0.01) compared with WT control. In contrast to AngII-infused WT mice, Cav1-/- mice with AngII showed attenuation of vascular remodeling but not cardiac hypertrophy ; HW/BW ratio (8.6±0.5 vs 6.4±0.2 p<0.05). Similar levels of AngII-induced hypertension were observed in both WT and Cav1-/- mice assessed by telemetry (MAP mmHg: 142±9 vs 154±20). In WT mice, Ang II enhanced ADAM17 expression and phospho-Tyr EGFR staining in heart and kidney vasculature. These events were attenuated in vessels from Cav1-/- mice infused with AngII. In addition, IHC analysis revealed less ER stress in heart and kidney vasculature of AngII-infused Cav1-/- mice compared with WT mice. Enhanced Cav1 and VCAM-1 expression were also observed in the aorta from AngII-infused WT mice but not in Cav1-/- aorta. These data suggest that Cav1 and presumably vascular caveolae play critical roles for vascular remodeling and inflammation via induction of ADAM17 and activation of EGFR independent of blood pressure or cardiac hypertrophy regulation.

scholarly journals Klotho-deficient mice are resistant to bone loss induced by unloading due to sciatic neurectomy

2001 ◽  
Vol 168 (2) ◽  
pp. 347-351 ◽  
Author(s):  
T Yamashita ◽  
I Sekiya ◽  
N Kawaguchi ◽  
K Kashimada ◽  
A Nifuji ◽  
...  
Keyword(s):  
Bone Loss ◽  
Cortical Bone ◽  
Gene Product ◽  
Mutant Mice ◽  
Wild Type ◽  
Micro Computed Tomography ◽  
Klotho Gene ◽  
Sciatic Neurectomy ◽  
And Control ◽  
Deficient Mice

Unloading induces bone loss as seen in experimental animals as well as in space flight or in bed-ridden conditions; however, the mechanisms involved in this phenomenon are not fully understood. Klotho mutant mice exhibit osteopetrosis in the metaphyseal regions indicating that the klotho gene product is involved in the regulation of bone metabolism. To examine whether the klotho gene product is involved in the unloading-induced bone loss, the response of the osteopetrotic cancellous bones in these mice was investigated. Sciatic nerve resection was conducted using klotho mutant (kl/kl) and control heterozygous mice (+/kl) and its effect on bone was examined by micro-computed tomography (microCT). As reported previously for wild-type mice (+/+), about 30% bone loss was induced in heterozygous mice (+/kl) by unloading due to neurectomy within 30 days of the surgery. By contrast, kl/kl mice were resistant against bone loss induced by unloading after neurectomy. Unloading due to neurectomy also induced a small but significant bone loss in the cortical bone of the mid-shaft of the femur in the heterozygous mice; no reduction in the cortical bone was observed in kl/kl mice. These results indicate that klotho mutant mice are resistant against bone loss induced by unloading due to neurectomy in both cortical and trabecular bone and indicate that klotho is one of the molecules involved in the loss of bone by unloading.

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.

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