Microbial biomass P, labile P, and acid phosphatase activity in the humus layer of a spruce forest, after repeated additions of fertilizers

1993 ◽  
Vol 16 (4) ◽  
pp. 287-292 ◽  
Author(s):  
M. Clarholm
Keyword(s):  
Acid Phosphatase ◽  
Microbial Biomass ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Spruce Forest ◽  
Humus Layer ◽  
Microbial Biomass P ◽  
Labile P

Biochemical inhibition of acid phosphatase activity in two mountain spruce forest soils

2021 ◽  
Author(s):  
Petr Čapek ◽  
Christopher P. Kasanke ◽  
Robert Starke ◽  
Qian Zhao ◽  
Karolina Tahovská
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Forest Soils ◽  
Acid Phosphatase Activity ◽  
Spruce Forest

Controls over phosphorus mineralization and immobilization rates in different tropical soils

2020 ◽  
Author(s):  
Lucia Fuchslueger ◽  
David Zezula ◽  
Johann Püspök ◽  
Leandro Van Langenhove ◽  
Olga Margalef ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Microbial Biomass ◽  
Phosphatase Activity ◽  
Sorption Capacity ◽  
Acid Phosphatase Activity ◽  
Tropical Soils ◽  
Microbial Biomass C ◽  
Organic P ◽  
P Mineralization ◽  
Total P

<p>Highly weathered soils depleted in minerals and phosphorus (P) support large tracts of the tropical rainforests in the Central Amazon, which significantly contribute to the global carbon (C) sink. In these soils (oxisols and ferrasols), P is either occluded in Al/Fe-oxides, bound to the soil mineral matrix or in soil organic matter, and therefore not directly available for uptake as inorganic phosphate (Pi). To liberate Pi for plant or microbial uptake two processes are key: (i) changes of sorption-desorption equilibria of Pi with the soil matrix and (ii) the release of Pi from organic compounds (Po) catalyzed by enzymes, such as phosphatases. Plant roots and soil microbes have developed strategies to stimulate the release of P by accelerating P dissolution and desorption and by releasing extracellular phosphatases into the soil environment, which requires however C and energy investment. Because of P limitation in this ecosystem, the relative contributions of abiotic and biotic controls over P mineralization is of pivotal importance. Yet conclusive results are still scarce.</p><p>We therefore aimed to disentangle abiotic and biotic controls over P mineralization in tropical soils. To achieve this, we collected forest soils from the Amazon Basin covering a range of soil texture and P concentrations, determined soil mineralogy and measured gross P desorption and mineralization rates using a <sup>33</sup>P isotope pool dilution assay. Moreover, we determined acid phosphatase activity rates and microbial biomass C and P. We found significant differences between the studied sites in gross P influx and efflux rates into the Pi pool. Gross influx rates (i.e. the sum of Pi desorption and organic P mineralization) exceeded efflux (i.e. sorption or biotic Pi uptake rates) only in sandy and silty soils, while in clayey soils efflux rates dominated P fluxes indicating a very high Pi sorption capacity. However, gross influx and efflux rates were not related to total or dissolved P. Microbial biomass and acid phosphatase activity normalized to microbial biomass C were highest in sites with overall low total P microbial biomass P accounting for up to 40 % of total P in low P soils. We therefore conclude that in low P soils organic P turnover plays a major role in soil P cycling, and despite of the high P sorption capacity of clay rich soils, microbes can be strong competitors for plant available P.</p>

Erythrophagocytosis in the Liver in Hemolytic Anemias

1968 ◽  
Vol 26 ◽  
pp. 184-185
Author(s):  
O. T. Minick ◽  
E. Orfei ◽  
F. Volini ◽  
G. Kent
Keyword(s):  
Acid Phosphatase ◽  
Oxidative Damage ◽  
Phosphatase Activity ◽  
Kupffer Cells ◽  
Acid Phosphatase Activity ◽  
Common Type ◽  
Red Cell ◽  
Cell Fragments ◽  
Reticulo Endothelial System ◽  
Important Site

Hemolytic anemias were produced in rats by administering phenylhydrazine or anti-erythrocytic (rooster) serum, the latter having agglutinin and hemolysin titers exceeding 1:1000.Following administration of phenylhydrazine, the erythrocytes undergo oxidative damage and are removed from the circulation by the cells of the reticulo-endothelial system, predominantly by the spleen. With increasing dosage or if animals are splenectomized, the Kupffer cells become an important site of sequestration and are greatly hypertrophied. Whole red cells are the most common type engulfed; they are broken down in digestive vacuoles, as shown by the presence of acid phosphatase activity (Fig. 1). Heinz body material and membranes persist longer than native hemoglobin. With larger doses of phenylhydrazine, erythrocytes undergo intravascular fragmentation, and the particles phagocytized are now mainly red cell fragments of varying sizes (Fig. 2).

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