Metabolomic profiling of the purple sulfur bacteriumAllochromatium vinosumduring growth on different reduced sulfur compounds and malate.
Environmental fluctuations require rapid adjustment of the physiology of bacteria. Anoxygenic phototrophic purple sulfur bacteria, likeAllochromatium vinosum, thrive in environments that are characterized by steep gradients of important nutrients for these organisms, i.e., reduced sulfur compounds, light, oxygen and carbon sources. Changing conditions necessitate changes on every level of the underlying cellular and molecular network. Thus far, two global analyses ofA. vinosumresponses to changes of nutritional conditions have been performed and these focused on gene expression and protein levels. Here, we provide a study on metabolite composition and relate it with transcriptional and proteomic profiling data to provide a more comprehensive insight on the systems level adjustment to available nutrients. We identified 131 individual metabolites and compared availability and concentration under four different growth conditions (sulfide, thiosulfate, elemental sulfur, and malate) and on sulfide for a ΔdsrJmutant strain. During growth on malate, cysteine was identified to be the least abundant amino acid. Concentrations of the metabolite classes "amino acids" and "organic acids" (i.e., pyruvate and its derivatives) were higher on malate than on reduced sulfur compounds by at least 20 and 50 %, respectively. Similar observations were made for metabolites assigned to anabolism of glucose. Growth on sulfur compounds led to enhanced concentrations of sulfur containing metabolites, while other cell constituents remained unaffected or decreased. Incapability of sulfur globule oxidation of the mutant strain was reflected by a low energy level of the cell and consequently reduced levels of amino acids (40 %) and sugars (65 %).
Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany.
Thomas
T
Weissgerber
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Science Park Potsdam - Golm, 14424 Potsdam, Germany.
Mutsumi
M
Watanabe
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Science Park Potsdam - Golm, 14424 Potsdam, Germany.
Rainer
R
Hoefgen
Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany.
Christiane
C
Dahl
Allochromatium vinosum; Assimilatory sulfate reduction; Metabolomic profiling; Purple sulfur bacteria; Sulfur oxidation