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Your search keyword '"von Gundlach, A. R."' showing total 3 results
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3 results on '"von Gundlach, A. R."'

1. Use of small-angle X-ray scattering to resolve intracellular structure changes of Escherichia coli cells induced by antibiotic treatment1

Author

von Gundlach, A. R., Garamus, V. M., Willey, T. M., Ilavsky, J., Hilpert, K., and Rosenhahn, A.

Subjects
Escherichia coli ultrastructure, ultra-small-angle X-ray scattering, small-angle X-ray scattering, transmission electron microscopy, USAXS, TEM, SAXS, Research Papers, antibiotics
Abstract

A combination of small- and ultra-small-angle X-ray scattering enabled the resolution of important intracellular constituents in Escherichia coli (ribosomes, DNA and proteins). The impact of treatment with three antibiotic agents was monitored., The application of small-angle X-ray scattering (SAXS) to whole Escherichia coli cells is challenging owing to the variety of internal constituents. To resolve their contributions, the outer shape was captured by ultra-small-angle X-ray scattering and combined with the internal structure resolved by SAXS. Building on these data, a model for the major structural components of E. coli was developed. It was possible to deduce information on the occupied volume, occurrence and average size of the most important intracellular constituents: ribosomes, DNA and proteins. E. coli was studied after treatment with three different antibiotic agents (chloramphenicol, tetracycline and rifampicin) and the impact on the intracellular constituents was monitored.

Published
2016

2. X‐ray fluorescence analysis of metal distributions in cryogenic biological samples using large‐acceptance‐angle SDD detection and continuous scanning at the Hard X‐ray Micro/Nano‐Probe beamline P06 at PETRA III.

Author

Rumancev, C., Gräfenstein, A., Vöpel, T., Stuhr, S., von Gundlach, A. R., Senkbeil, T., Garrevoet, J., Jolmes, L., König, B., Falkenberg, G., Ebbinghaus, S., Schroeder, W. H., and Rosenhahn, A.

Subjects
X-ray spectroscopy, HARD X-rays, METAL analysis, X-ray fluorescence, BIOLOGICAL specimens, HELA cells, TRACE elements, LIQUID nitrogen
Abstract

A new Rococo 2 X‐ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X‐ray Micro/Nano‐Probe beamline P06 at PETRA III, DESY, Hamburg, Germany. A four sensor‐field cloverleaf design is optimized for the investigation of planar samples and operates in a backscattering geometry resulting in a large solid angle of up to 1.1 steradian. The detector, coupled with the Xspress 3 pulse processor, enables measurements at high count rates of up to 106 counts per second per sensor. The measured energy resolution of ∼129 eV (Mn Kα at 10000 counts s−1) is only minimally impaired at the highest count rates. The resulting high detection sensitivity allows for an accurate determination of trace element distributions such as in thin frozen hydrated biological specimens. First proof‐of‐principle measurements using continuous‐movement 2D scans of frozen hydrated HeLa cells as a model system are reported to demonstrate the potential of the new detection system. [ABSTRACT FROM AUTHOR]

Published
2020
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