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Rising temperatures in the Arctic can affect soil organic matter (SOM) decomposition directly and indirectly, by increasing plant primary production and thus the allocation of plant-derived organic compounds into the soil. Such compounds, for example root exudates or decaying fine roots, are easily available for microorganisms, and can alter the(More)
Enterotoxigenic anaerobic Bacteroides fragilis is a significant source of inflammatory diarrheal disease and a risk factor for colorectal cancer. Two distinct metalloproteinase types (the homologous 1, 2, and 3 isoforms of fragilysin (FRA1, FRA2, and FRA3, respectively) and metalloproteinase II (MPII)) are encoded by the B. fragilis pathogenicity island.(More)
[Chemical reaction: See text] Enantiomerically or diastereomerically pure 4-(purin-6-yl)phenylalanines, a novel type of stable amino acid-purine conjugates, were synthesized by palladium-catalyzed cross-coupling reactions of protected 4-boronophenylalanines or 4-(trimethylstanyl)phenylalanines with diverse 6-halopurines (9-benzyl-6-halopurines and(More)
Cryoturbation, the burial of topsoil material into deeper soil horizons by repeated freeze-thaw events, is an important storage mechanism for soil organic matter (SOM) in permafrost-affected soils. Besides abiotic conditions, microbial community structure and the accessibility of SOM to the decomposer community are hypothesized to control SOM decomposition(More)
Turbic Cryosols (permafrost soils characterized by cryoturbation, i.e., by mixing of soil layers due to freezing and thawing) are widespread across the Arctic, and contain large amounts of poorly decomposed organic material buried in the subsoil. This cryoturbated organic matter exhibits retarded decomposition compared to organic material in the topsoil.(More)
Enzyme-mediated decomposition of soil organic matter (SOM) is controlled, amongst other factors, by organic matter properties and by the microbial decomposer community present. Since microbial community composition and SOM properties are often interrelated and both change with soil depth, the drivers of enzymatic decomposition are hard to dissect. We(More)
(Purin-6-yl)alanines, a new class of amino acid-nucleobase conjugates, were synthesized by palladium-catalyzed cross-coupling reactions of protected iodozincalanines with 6-iodopurines (9-Bn-6-iodopurine and 9-THP-6-iodopurine as well as acyl-protected 6-iodopurine ribonucleoside and 2-deoxyribonucleoside). Free purine base and nucleosides bearing alanine(More)
DNA is inherently limited by its four natural nucleotides. Efforts to expand the genetic alphabet, by addition of an unnatural base pair, promise to expand the biotechnological applications available for DNA as well as to be an essential first step toward expansion of the genetic code. We have conducted two independent screens of hydrophobic unnatural(More)
We report a scalable and cost-effective technology for generating and screening high-complexity customizable peptide sets. The peptides are made as peptide-cDNA fusions by in vitro transcription/translation from pools of DNA templates generated by microarray-based synthesis. This approach enables large custom sets of peptides to be designed in silico,(More)
Single-step aqueous cross-coupling reactions of nucleobase-halogenated 2'-deoxynucleosides (8-bromo-2'-deoxyadenosine, 7-iodo-7-deaza-2'-deoxyadenosine, or 5-iodo-2'-deoxy-uridine) or their 5'-triphosphates with 4-boronophenylalanine or 4-ethynylphenylalanine have been developed and used for efficient synthesis of modified 2'-deoxynucleoside triphosphates(More)