Valence satellite and 3p photoelectron spectra of atomic Fe and Cu

The 3p photoelectron spectra of atomic Fe and Cu, and the Fe outer-shell satellites have been investigated. The complex multiline structure of the Fe spectra has been resolved using high-resolution electron spectroscopy. The thresholds of the direct 3p photoionization have been determined and are compared with experimental results from photoabsorption measurements and Auger spectra, and with the multiplet structures calculated taking into account intershell and configuration interaction. The stepwise decay of highly excited Fe states into has been verified by the detection of satellite lines with binding energies above the lowest ionization threshold

Determination of Ca 2p ionization thresholds by high-resolution photoelectron spectroscopy

The energies of the closely spaced Ca 2p thresholds have been determined by crossing an atomic beam of calcium with the monochromatized synchrotron radiation from the high-resolution undulator beamline SX 700 - BW3 at HASYLAB and analysing the kinetic energy of the outgoing photoelectrons with a high-resolution SCIENTA SES 200 electron analyser. The experimental results are compared to the predictions of different theoretical approaches and the strong influence of electron correlation in the core ionized state is demonstrated

High resolution spectroscopy of 2p6→2p53d2p^6\to2p^53d resonantly excited atomic Ca

Free calcium atoms were excited in the energy region about 10 eV below the 2p thresholds. For the excitation, synchrotron radiation from the high resolution undulator beamline BW3 (HASYLAB, Hamburg) equipped with a SX-700 monochromator was used. The excited atoms were studied by means of ion as well as electron spectroscopy. Two lines could be resolved within one of the two dominating features of the 2p→3d resonance. Resonance enhanced 3p−1 photoelectron spectra resolving the 2P12 and 2P32 lines are presented

Characterization of different alginate lyases for dissolving Pseudomonas aeruginosa biofilms

Aggregates of Pseudomonas aeruginosa form a protective barrier against antibiotics and the immune system. These barriers, known as biofilms, are associated with several infectious diseases. One of the main components of these biofilms is alginate, a homo- and hetero-polysaccharide that consists of β-D-mannuronate (M) and α-L-guluronate (G) units. Alginate lyases degrade this sugar and have been proposed as biotherapeutic agents to dissolve P. aeruginosa biofilms. However, there are contradictory reports in the literature regarding the efficacy of alginate lyases against biofilms and their synergistic effect with antibiotics. We found that most positive reports used a commercial crude extract from Flavobacterium multivorum as the alginate lyase source. By using anion exchange chromatography coupled to nano LC MS/MS, we identified two distinct enzymes in this extract, one has both polyM and polyG (polyM/G) degradation activities and it is similar in sequence to a broad-spectrum alginate lyase from Flavobacterium sp. S20 (Alg2A). The other enzyme has only polyG activity and it is similar in sequence to AlyA1 from Zobellia galactanivorans. By characterizing both of these enzymes together with three recombinant alginate lyases (a polyM, a polyG and a polyM/G), we showed that only enzymes with polyM/G activity such as Alg2A and A1-II' (alginate lyase from Sphingomonas sp.) are effective in dissolving biofilms. Furthermore, both activities are required to have a synergistic effect with antibiotics.We acknowledge support of the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program under agreement No 670216 (MYCOCHASSIS), the Spanish Ministry of Economy and Competitiveness and Fondo Europeo de Desarrollo Regional (MINECO-FEDER) (BIO2015-63557-R), ‘Centro de Excelencia Severo Ochoa 2013-2017’, FEDER project from Instituto Carlos III (ISCIII, Acción Estratégica en Salud 2016) (reference CP16/00094) and “Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya / CERCA programme” (2014SGR678 and 2017SGR1079). The CRG/UPF Proteomics Unit is part of the “Plataforma de Recursos Biomoleculares y Bioinformáticos (ProteoRed)” supported by grant PT13/0001 of Instituto de Salud Carlos III from the Spanish Government