English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The current analytical technique for measuring microbial extracellular enzyme activity within natural samples of water, soil or sediment involves incubation of samples with specific substrates conjugated with a fluorophore such as 7-amino-4-methylcoumarin (AMC) or methylumbelliferone (MUF). In this procedure, the extracellular enzymatic reaction IS usually terminated by freezlng and the reactlon mixture is then stored frozen for later analysis. Unfortunately, the precision of this assay is limited by the reactivation of extracellular enzymes which can occur when samples are thawed and by the adsorption of liberated fluorophore onto the sediment which cannot be quantified without proper controls. To overcome these limitations, we describe a simple method using extreme pH ( 11) to terminate extracellular enzymatic reactions. Studies of aminopeptidase (AMPase) and P-glucosidase (PGase) activity in marine sediments have also shown that addition of HCl and NaOH, respectively, eliminated the reactivation of extracellular enzymes when frozen samples were thawed. Furthermore, acetone and NaOH additions also reduced the interference caused by the adsorption of fluorophores to the sediment Linearity of standard curves for fluorophores In the presence of these added chemicals were maintamed and additional use of acetone increased AMC fluorescence (-20%). Modifications descnbed in this report significantly reduced the level of variability In the determination of extracellular enzyme activity in marine sediments and allowed the simultaneous treatment of numerous samples.

Microbial extracellular enzyme activity in marine sediments: extreme pH to terminate reaction and sample storage