Universal, untargeted detection of bacteria in tissues using metabolomics workflows.

Fast and reliable identification of bacteria directly in clinical samples is a critical factor in clinical microbiological diagnostics. Current approaches require time-consuming bacterial isolation and enrichment procedures, delaying stratified treatment. Here, we describe a biomarker-based strategy that utilises bacterial small molecular metabolites and lipids for direct detection of bacteria in complex samples using mass spectrometry (MS).

Improvement of the antimicrobial potency, pharmacokinetic and pharmacodynamic properties of albicidin by incorporation of nitrogen atoms.

The worrisome development and spread of multidrug-resistant bacteria demands new antibacterial agents with strong bioactivities particularly against Gram-negative bacteria. Albicidins were recently structurally characterized as highly active antibacterial natural products from the bacterium . Albicidin, which effectively targets the bacterial DNA-gyrase, is a lipophilic hexapeptide mostly consisting of amino benzoic acid units and only one α-amino acid.

Overcoming AlbD Protease Resistance and Improving Potency: Synthesis and Bioactivity of Antibacterial Albicidin Analogues with Amide Bond Isosteres.

Albicidin is a potent antibacterial oligoaromatic peptide that is susceptible to the protease AlbD, a resistance factor. This potentially restricts the use of albicidin as a drug. To overcome this obstacle, we synthesized and evaluated six analogues with isosteric replacement of the key amide link.

Mechanism of the Thermal Z⇌E Isomerization of a Stable Silene; Experiment and Theory.

The E and Z geometric isomers of a stable silene (tBu MeSi)(tBuMe Si)Si=CH(1-Ad) (1) were synthesized and characterized spectroscopically. The thermal Z to E isomerization of 1 was studied both experimentally and computationally using DFT methods. The measured activation parameters for the 1Z⇌1E isomerization are: E =24.

Sequence and Structure of Peptoid Oligomers Can Tune the Photoluminescence of an Embedded Ruthenium Dye.

The understanding of structure-function relationships within synthetic biomimetic systems is a fundamental challenge in chemistry. Herein we report the direct correlation between the structure of short peptoid ligands-N-substituted glycine oligomers incorporating 2,2'-bipyridine groups-varied in their monomer sequence, and the photoluminescence of Ru centers coordinated by these ligands. Based on circular dichroism and fluorescence spectroscopy we demonstrate that while helical peptoids do not affect the fluorescence of the embedded Ru chromophore, unstructured peptoids lead to its significant decay.

Generation and EPR Spectroscopy of the First Silenyl Radicals, R C=Si -R: Experiment and Theory.

The first two persistent silenyl radicals (R C=Si -R), with a half-life (t ) of about 30 min, were generated and characterized by electron paramagnetic resonance (EPR) spectroscopy. The large hyperfine coupling constants (hfccs) (a( Si )=137.5-148.

A Pure Polyproline Type I-like Peptoid Helix by Metal Coordination.

Peptoids, N-substituted glycine oligomers, are an important class of foldamers that can adopt polyproline-type helices (PP-I and PP-II), given that the majority of their sequence consists of chiral, bulky side chains. Herein a new approach for the stabilization of a pure PP-I-like peptoid helix through metal coordination is introduced. A systematic spectroscopic study was performed on a series of peptoid heptamers bearing two 8-hydroxyquinoline ligands at fixed positions, and a mixture of chiral benzyl and alkyl substituents in varied positions along the peptoid backbone.

Synthesis of silenyllithiums Li(R'3Si)Si═C(SiR3)(1-Ad) via transient silyne-silylidene intermediates.

The first two lithium silenides, Li(tBu(2)MeSi)Si═C(SiMetBu(2))(1-Ad) (1) and Li(tBuMe(2)Si)Si═C(SiMetBu(2))(1-Ad) (2) were prepared by THF addition to the corresponding lithium-silenolates, [(tBu(2)MeSi)(2)Si═C(OLi)(1-Ad)]·(R(3)SiLi) (3a: R(3)Si═tBu(2)MeSi, 3b: R(3)Si═tBuMe(2)Si). 1 and 2 were crystallized, and their structures were determined by X-ray crystallography. This process requires the presence of both coaggregated silyllithium (R(3)SiLi) (3a and 3b) and THF.