TY - JOUR A1 - Weißhaupt, Petra A1 - Naumann, Annette A1 - Pritzkow, Wolfgang A1 - Noll, Matthias T1 - Nitrogen uptake of hypholoma fasciculare and coexisting bacteria N2 - The white-rot fungus Hypholoma fasciculare coexists with a bacterial community that uses low-molecular weight carbon sources provided by fungal, extracellular enzyme activities. Since fungal development on wood is limited by the availability of nitrogen (N), bacteria could contribute to the N supply. To prove or disapprove an interaction in terms of N transfer, N sources of the fungus and the coexisting bacterial isolates were investigated, and the bacterial N2 fixation was quantified. Fungal, fungal—bacterial and bacterial wood decomposition was analysed by Fourier transform infrared spectroscopy (FTIR), mass loss and surface pH. Microbial N preferences were investigated by elemental analysis isotope ratio mass spectrometry (IRMS). In addition, diazotrophic activity was explored after cultivation under a 15N2/O2 atmosphere. Decomposition was similar with and without bacteria and both H. fasciculare and coexisting bacteria preferred reduced N species, such as urea, ammonium and organic N. In most of the bacteria, the 15N abundance in the biomass increased significantly but to a low extent if they were cultivated under a 15N2/O2 atmosphere. This effect is considered an artefact and attributed to adsorption rather than to bacterial N2 fixation activity. Hence, the bacteria coexisting with H. fasciculare rather competed for the same N sources than supported fungal N supply by diazotrophic activity. KW - Hypholoma fasciculare KW - Proteobacteria KW - Fungal-bacterial interaction KW - 15N2 fixation KW - FTIR-ATR spectroscopy KW - IRMS PY - 2013 U6 - https://doi.org/10.1007/s11557-012-0834-x SN - 1617-416X SN - 1861-8952 VL - 12 IS - 2 SP - 283 EP - 290 PB - Springer CY - Heidelberg AN - OPUS4-28867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogl, Jochen A1 - Paz, B. A1 - Koenig, Maren A1 - Pritzkow, Wolfgang T1 - A modified lead-matrix separation procedure shown for lead isotope analysis in Trojan silver artefacts as an example N2 - A modified Pb–matrix separation procedure using NH4HCO3 solution as eluent has been developed and validated for determination of Pb isotope amount ratios by thermal ionization mass spectrometry. The procedure is based on chromatographic separation using the Pb·Spec resin and an in-house-prepared NH4HCO3 solution serving as eluent. The advantages of this eluent are low Pb blanks (<40 pgmL-1) and the property that NH4HCO3 can be easily removed by use of a heating step (>60 °C). Pb recovery is >95 % for water samples. For archaeological silver samples, however, the Pb recovery is reduced to approximately 50 %, but causes no bias in the determination of Pb isotope amount ratios. The validated procedure was used to determine lead isotope amount ratios in Trojan silver artefacts with expanded uncertainties (k=2) <0.09 %. KW - Analyte-matrix separation KW - Mass spectrometry KW - Pb isotope ratio thermal ionization mass spectrometry KW - Archaeometry PY - 2013 U6 - https://doi.org/10.1007/s00216-012-6323-x SN - 1618-2642 SN - 1618-2650 VL - 405 IS - 9 SP - 2995 EP - 3000 PB - Springer CY - Berlin AN - OPUS4-28170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogl, Jochen A1 - Rosner, Martin A1 - Pritzkow, Wolfgang T1 - The need for new isotope reference materials N2 - Isotope reference materials are needed to calibrate and validate analytical procedures used for the determination of isotope amount ratios, procedurally defined isotope ratios or so-called δ values. In contrast to the huge analytical progress in isotope ratio analytics, the production of isotope reference materials has not kept pace with the increasing needs of isotope analysts. Three representative isotope systems are used to explain the technical and non-technical difficulties and drawbacks, on one hand, and to demonstrate what can be achieved at its best, on the other hand. A clear statement is given that new isotope reference materials are needed to obtain traceable and thus comparable data, which is essential for all kinds of isotope research. The range of available isotope reference materials and δ reference materials should be increased and matrix reference materials certified for isotope compositions or δ values, which do not exist yet, should be provided. KW - Isotope reference materials KW - Delta reference materials KW - Synthetic isotope mixtures KW - Mass spectrometry KW - Comparability KW - Traceability KW - Measurement uncertainty PY - 2013 U6 - https://doi.org/10.1007/s00216-012-6605-3 SN - 1618-2642 SN - 1618-2650 VL - 405 IS - 9 SP - 2763 EP - 2770 PB - Springer CY - Berlin AN - OPUS4-28169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -