produces 2-alkylquinolone derivatives important for host virulence and competition with bacteria that employ naphthoquinones for aerobic respiration.

Melioidosis is caused by , an opportunistic Gram-negative pathogen that inhabits soil and water in tropical and subtropical regions. infections often occur following contact with contaminated water or soil or by inhalation of contaminated dust and water droplets. There is limited knowledge about how is able to survive in harsh environmental conditions and compete with the microbes that inhabit these niches.

Electronic structure, bonding and stability of fumarate, maleate, and succinate dianions from X-ray spectroscopy.

The electronic structure of the fumarate, maleate, and succinate dianions in the context of their stability is determined in a joint experimental and computational study with X-ray absorption spectroscopy and resonant inelastic X-ray scattering at the O K-edge. The study reveals differences in the electronic states and molecular orbitals of the three molecules. In particular, maleate has a non-degenerate oxygen core-orbital with an energy difference of approximately 0.

Wave packet theory for non-resonant x-ray emission and non-resonant Auger electron emission in molecules.

We present a time-dependent theory for non-resonant x-ray emission spectrum (XES) and normal Auger spectrum (NAS) calculation, based on a fully quantum description of nuclear dynamics using the vibrational wave packet concept. We compare two formulations of the time-dependent theory, either employing a two-time propagation scheme or using spectral integration over the electron energy continuum. We find that the latter formulation is more efficient for numerical simulations, providing a reasonable accuracy when the integration step is shorter than the lifetime broadening of the core-ionized state.

Biosynthetic flexibility of Pseudomonas aeruginosa leads to hydroxylated 2-alkylquinolones with proinflammatory host response.

The human pathogen Pseudomonas aeruginosa produces various 4(1H)-quinolones with diverse functions. Among these, 2-nonyl-4(1H)-quinolone (NQ) and its N-oxide (NQNO) belong to the main metabolites. Their biosynthesis involves substrates from the fatty acid metabolism and we hypothesized that oxidized fatty acids could be responsible for a so far undetected class of metabolites.

Beyond iron: metal-binding activity of the quinolone signal-motif.

The quinolone signal (PQS) is an important quorum sensing signal controlling virulence of the human pathogen . PQS also exhibits multiple additional biological functions for . , including the trapping of ferric iron.

Hydrogen bond effects in multimode nuclear dynamics of acetic acid observed via resonant x-ray scattering.

A theoretical and experimental study of the gas phase and liquid acetic acid based on resonant inelastic x-ray scattering (RIXS) spectroscopy is presented. We combine and compare different levels of theory for an isolated molecule for a comprehensive analysis, including electronic and vibrational degrees of freedom. The excitation energy scan over the oxygen K-edge absorption reveals nuclear dynamic effects in the core-excited and final electronic states.

Vibrational resonant inelastic X-ray scattering in liquid acetic acid: a ruler for molecular chain lengths.

Quenching of vibrational excitations in resonant inelastic X-ray scattering (RIXS) spectra of liquid acetic acid is observed. At the oxygen core resonance associated with localized excitations at the O-H bond, the spectra lack the typical progression of vibrational excitations observed in RIXS spectra of comparable systems. We interpret this phenomenon as due to strong rehybridization of the unoccupied molecular orbitals as a result of hydrogen bonding, which however cannot be observed in x-ray absorption but only by means of RIXS.

Nuclear dynamics in resonant inelastic X-ray scattering and X-ray absorption of methanol.

We report on a combined theoretical and experimental study of core-excitation spectra of gas and liquid phase methanol as obtained with the use of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The electronic transitions are studied with computational methods that include strict and extended second-order algebraic diagrammatic construction [ADC(2) and ADC(2)-x], restricted active space second-order perturbation theory, and time-dependent density functional theory-providing a complete assignment of the near oxygen K-edge XAS. We show that multimode nuclear dynamics is of crucial importance for explaining the available experimental XAS and RIXS spectra.

Ultrafast dissociation features in RIXS spectra of the water molecule.

In this combined theoretical and experimental study we report on an analysis of the resonant inelastic X-ray scattering (RIXS) spectra of gas phase water via the lowest dissociative core-excited state |1s-1O4a11. We focus on the spectral feature near the dissociation limit of the electronic ground state. We show that the narrow atomic-like peak consists of the overlapping contribution from the RIXS channels back to the ground state and to the first valence excited state |1b-114a11 of the molecule.