Source Themes

Phylogenetically Novel Uncultured Microbial Cells Dominate Earth Microbiomes

To describe a microbe’s physiology, including its metabolism, environmental roles, and growth characteristics, it must be grown in a laboratory culture. Unfortunately, many phylogenetically novel groups have never been cultured, so their physiologies …

Understanding Electrochemically Activated Persulfate and Its Application to Ciprofloxacin Abatement

This study offers insight into the roles anodic and cathodic processes play in electrochemically activated persulfate (EAP) and screens EAP as a viable technique for ciprofloxacin degradation in wastewater. Sulfate radical formation at a boron-doped …

Potential Activities of Freshwater Exo- and Endo-Acting Extracellular Peptidases in East Tennessee and the Pocono Mountains

Proteins constitute a particularly bioavailable subset of organic carbon and nitrogen in aquatic environments but must be hydrolyzed by extracellular enzymes prior to being metabolized by microorganisms. Activities of extracellular peptidases …

Sequential bioavailability of sedimentary organic matter to heterotrophic bacteria

Aquatic sediments harbour diverse microbial communities that mediate organic matter degradation and influence biogeochemical cycles. The pool of bioavailable carbon continuously changes as a result of abiotic processes and microbial activity. It …

Evidence for the Priming Effect in a Planktonic Estuarine Microbial Community

The “priming effect,” in which addition of labile substances changes the remineralization rate of recalcitrant organic matter, has been intensively studied in soils, but is less well-documented in aquatic systems. We investigated the extent to which …

Substrate specificity of aquatic extracellular peptidases assessed by competitive inhibition assays using synthetic substrates

The identities and biochemical properties of extracellular enzymes present in natural environments are poorly constrained. We used a series of competitive inhibition experiments with samples from a freshwater environment (the Tennessee River at …

New aminopeptidase from “microbial dark matter” archaeon

Marine sediments host a large population of diverse, heterotrophic, uncultured microorganisms with unknown physiologies that control carbon flow through organic matter decomposition. Recently, single-cell genomics uncovered new key players in these …

Picky, hungry eaters in the cold: persistent substrate selectivity among polar pelagic microbial communities

Extracellular enzymes in terrestrial, freshwater, and marine environments: Perspectives on system variability and common research needs

Extracellular enzymes produced by heterotrophic microbial communities are major drivers of carbon and nutrient cycling in terrestrial, freshwater, and marine environments. Although carbon and nutrient cycles are coupled on global scales, studies of …

Verrucomicrobia Are Candidates for Polysaccharide-Degrading Bacterioplankton in an Arctic Fjord of Svalbard

In Arctic marine bacterial communities, members of the phylum *Verrucomicrobia* are consistently detected, although not typically abundant, in 16S rRNA gene clone libraries and pyrotag surveys of the marine water column and in sediments. In an Arctic …