scholarly journals EFFECT OF PREGNANCY ON THE PHOSPHORUS TURNOVER OF THE SKELETON OF RATS MAINTAINED ON NORMAL AND RACHITOGENIC DIETS

1941 ◽  
Vol 139 (1) ◽  
pp. 35-41
Author(s):  
Marian LeFevre Manly ◽  
Sylvia Ruth Levy
Keyword(s):  
1973 ◽  
Vol 132 (3) ◽  
pp. 475-482 ◽  
Author(s):  
Martin Reddington ◽  
Richard Rodnight ◽  
Michael Williams

1. The effect of various agents on the turnover of protein-bound phosphorus in respiring slices of cerebral cortex was studied. 2. Confirming previous work turnover was increased by the application of electrical pulses for 10s to the tissue. 3. Turnover was also increased by exposure of the slices for 10min to noradrenaline (0.5mm), 5-hydroxytryptamine (1μm) and histamine (0.1mm). 4. When slices were stimulated by electrical pulses in the presence of histamine the increase in turnover was the sum of the responses given by each agent above, suggesting that different phosphorylating systems were involved. 5. Tetrodotoxin (0.5μm) blocked the increased turnover due to electrical pulses, but not that due to histamine. Tetrodotoxin also prevented the increase in tissue cyclic AMP content caused by the application of electrical pulses. 6. Phosphoprotein turnover was not affected by adenosine, despite the increase in tissue cyclic AMP content given by this agent. 7. Adenosine blocked the phosphoprotein response to histamine, but did not affect the response to electrical pulses. 8. The results are discussed in relation to the hypothesis that the stimulation of protein phosphorus turnover by electrical pulses is secondary to the release of cyclic AMP in the tissue.


Cancer ◽  
1951 ◽  
Vol 4 (2) ◽  
pp. 410-415 ◽  
Author(s):  
A. Clark Griffin ◽  
Lew Cunningham ◽  
Eugenia L. Brandt ◽  
D. W. Kupke

1987 ◽  
Vol 24 (3) ◽  
pp. 969 ◽  
Author(s):  
A. P. Jupp ◽  
E. I. Newman ◽  
K. Ritz

1983 ◽  
Vol 40 (11) ◽  
pp. 1853-1860 ◽  
Author(s):  
B. G. Brownlee ◽  
T. P. Murphy

Nitrogen fixation by Aphanizomenon flos-aquae in a prairie lake in southwestern Manitoba was dependent on the light intensity and in situ oxygen concentrations. The mean molar ratio of acetylene reduction to nitrogen reduction was 5.8:1. High external ammonium concentrations did not appear to inhibit nitrogen fixation over the short term. Nitrogen fixation was not directly initiated by the bloom collapse. We propose that the coupled sequence of ammonia volatilization and nitrogen fixation was triggered by the bloom collapse and that the bloom collapse was caused by coprecipitation of orthophosphate with carbonates. 32PO4 turnover was most rapid during periods when the lake was opalescent, presumably due to carbonate precipitaton.


2021 ◽  
Author(s):  
Antonio Pedro Camargo ◽  
Rafael Soares Correa de Souza ◽  
Juliana Jose ◽  
Isabel Rodrigues Gerhardt ◽  
Ricardo Augusto Dante ◽  
...  

The substrates of the Brazilian campos rupestres have extremely low concentrations of key nutrients, mainly phosphorus, imposing severe restrictions to plant growth. Regardless, this ecosystem harbors enormous biodiversity which raises the question of how nutrients are cycled and acquired by the biosphere. To uncover the nutrient turnover potential of plant-associated microorganisms in the campos rupestres, we investigated the compositions and functions of microbiomes associated with two species of the Velloziaceae family that grow over distinct substrates (soil and rock). Amplicon, metagenomic, and metagenome-assembled genome sequence data showed that the campos rupestres harbor a novel assemblage of plant-associated prokaryotes and fungi. Compositional analysis revealed that the plant-associated soil and rock communities differed in taxonomic structure but shared a core of highly efficient colonizers that were strongly coupled with nutrient mobilization. Investigation of functional and abundance data revealed that the plant hosts actively recruit communities by exuding organic compounds and that the root-associated microbiomes possess a diverse repertoire of phosphorus turnover mechanisms. We also showed that the microbiomes of both plant species encompass novel populations capable of mobilizing nitrogen and that the substrate strongly influences the dynamics of this cycle. Our results show that the interplay between plants and their microbiomes shapes nutrient turnover in the campos rupestres. We highlight that investigation of microbial diversity is fundamental to understand plant fitness in stressful environments.


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