Current standard assays using artificial substrates overestimate phosphodiesterase activity

Sirová, Dagmara; Rejmánková, Eliška; Carlson, Emily M.; Vrba, Jaroslav

doi:10.1016/j.soilbio.2012.02.008

Cited by 10 publications

(4 citation statements)

References 15 publications

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“…6b). Phosphomonoesterases were found to have the highest activities despite the inherent overestimation of phosphodiesterase activities when using MUF-tagged substrates (Sirová et al, 2013). The opposite trend was observed for glycopyranoside, part of the cellulose degradation pathway (Dunn et al, 2013), which showed consistently higher activity (69 % p =< 0.05) under anoxic conditions (Fig.…”

Section: Hydrolytic Enzyme Activitiesmentioning

confidence: 84%

Sediment phosphorus speciation and mobility under dynamic redox conditions

Parsons¹,

Rezanezhad²,

O’Connell³

et al. 2017

Biogeosciences

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Abstract. Anthropogenic nutrient enrichment has caused phosphorus (P) accumulation in many freshwater sediments, raising concerns that internal loading from legacy P may delay the recovery of aquatic ecosystems suffering from eutrophication. Benthic recycling of P strongly depends on the redox regime within surficial sediment. In many shallow environments, redox conditions tend to be highly dynamic as a result of, among others, bioturbation by macrofauna, root activity, sediment resuspension and seasonal variations in bottom-water oxygen (O 2 ) concentrations. To gain insight into the mobility and biogeochemistry of P under fluctuating redox conditions, a suspension of sediment from a hypereutrophic freshwater marsh was exposed to alternating 7-day periods of purging with air and nitrogen gas (N 2 ), for a total duration of 74 days, in a bioreactor system. We present comprehensive data time series of bulk aqueous-and solidphase chemistry, solid-phase phosphorus speciation and hydrolytic enzyme activities demonstrating the mass balanced redistribution of P in sediment during redox cycling. Aqueous phosphate concentrations remained low (∼ 2.5 µM) under oxic conditions due to sorption to iron(III) oxyhydroxides. During anoxic periods, once nitrate was depleted, the reductive dissolution of iron(III) oxyhydroxides released P. However, only 4.5 % of the released P accumulated in solution while the rest was redistributed between the MgCl 2 and NaHCO 3 extractable fractions of the solid phase. Thus, under the short redox fluctuations imposed in the experiments, P remobilization to the aqueous phase remained relatively limited. Orthophosphate predominated at all times during the experiment in both the solid and aqueous phase. Combined P monoesters and diesters accounted for between 9 and 16 % of sediment particulate P. Phosphatase activities up to 2.4 mmol h −1 kg −1 indicated the potential for rapid mineralization of organic P (P o ), in particular during periods of aeration when the activity of phosphomonoesterases was 37 % higher than under N 2 sparging. The results emphasize that the magnitude and timing of internal P loading during periods of anoxia are dependent on both P redistribution within sediments and bottom-water nitrate concentrations.

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Section: Hydrolytic Enzyme Activitiesmentioning

confidence: 84%

Sediment phosphorus speciation and mobility under dynamic redox conditions

Parsons¹,

Rezanezhad²,

O’Connell³

et al. 2017

Biogeosciences

View full text Add to dashboard Cite

show abstract

“…CC BY 4.0 License. microbial biomass (Green et al, 2006;Schnurer and Rosswall, 1982), and the activity of acid phosphomonoesterases, which are extracellular enzymes involved in Po mineralization, was determined using methylumbelliferyl (MUF)-phosphate (Sirova et al, 2013;Marx et al, 2001 (Kellogg et al, 2006;Mooshammer et al, 2012). Isobutanol partitioning enables 100% recovery of Pi with no hydrolysis of Po (Jayachandran et al, 1992).…”

Section: Soil Pre-treatment and Assay Of Sterilization Efficiency (Abmentioning

confidence: 99%

A novel isotope pool dilution approach to quantify gross rates of key abiotic and biological processes in the soil phosphorus cycle

Wanek¹,

Zezula²,

Wasner³

et al. 2019

Preprint

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Abstract. Efforts to understand and model the current and future behavior of the global phosphorus (P) cycle are limited by the availability of global data on gross rates of soil P processes, as well as its environmental controls. We here present a novel isotope pool dilution approach using 33P labelling of live and sterile soils, which allows to obtain high quality data on gross fluxes of soil inorganic P (Pi) sorption and desorption, as well as of gross fluxes of organic P mineralization and microbial Pi uptake. At the same time, net immobilization of 33Pi by soil microbes and abiotic sorption can be easily derived and partitioned. Compared to other approaches, we used short incubation times (up to 48&#8201;h), avoiding tracer re-mineralization, which was confirmed by separation of organic P and Pi using isobutanol fractionation. This approach is also suitable for strongly weathered and P impoverished soils, as sensitivity is increased by extraction of exchangeable bio-available Pi (Olsen Pi; 0.5&#8201;M NaHCO3) followed by Pi measurement using the malachite green assay. Biotic processes were corrected for desorption/sorption processes by using adequate sterile abiotic controls that exhibited negligible microbial and extracellular phosphatase activities. Gross rates are calculated using analytical solutions of tracer kinetics, which also allows to study gross soil P dynamics under non-steady-state conditions. Finally, we present major environmental controls of gross and net P cycle processes that were measured for three P-poor tropical forest and three P-rich temperate grassland soils.

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“…Also for other plants, phytase activity was substantially lower than activity of non-phytase phosphomonoesterases (Hayes et al, 1999;Richardson et al, 2000;Viveros et al, 2000;Richardson et al, 2001;Louw-Gaume et al, 2010), and several studies have reported that a significant release of phytase from plant roots was achieved only by genetic manipulation (Richardson et al, 2001;Zimmermann et al, 2003;George et al, 2005b;Xiao et al, 2005). While the activity of non-phytase phosphomonoesterase in roots of wetland plants was similar to that of phosphodiesterase (Rejmánková et al, 2011), it should be noted that the activity of phosphodiesterases can be easily overestimated by the presence of phosphomonoesterases when using artificial substrate for enzyme activity determinations (Sirová et al, 2013). With a few exceptions, microbes produce only intracellular phytases (Singh et al, 2018).…”

Section: Enzyme-limited Hydrolysis Of Phytate and Phosphodiesters In mentioning

confidence: 96%

Is the enzymatic hydrolysis of soil organic phosphorus compounds limited by enzyme or substrate availability?

Jarosch

Kandeler

Frossard

et al. 2019

Soil Biology and Biochemistry

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Current standard assays using artificial substrates overestimate phosphodiesterase activity

Cited by 10 publications

References 15 publications

Sediment phosphorus speciation and mobility under dynamic redox conditions

Sediment phosphorus speciation and mobility under dynamic redox conditions

A novel isotope pool dilution approach to quantify gross rates of key abiotic and biological processes in the soil phosphorus cycle

Is the enzymatic hydrolysis of soil organic phosphorus compounds limited by enzyme or substrate availability?

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