Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Al Shweiki, M. R.; Mönchgesang, S.; Majovsky, P.; Thieme, D.; Trutschel, D.; Hoehenwarter, W.;Assessment of Label-Free Quantification in Discovery Proteomics and Impact of Technological Factors and Natural Variability of Protein AbundanceJ. Proteome Res.161410-1424(2017)DOI: 10.1021/acs.jproteome.6b00645
We evaluated the state of label-free discovery proteomics focusing especially on technological contributions and contributions of naturally occurring differences in protein abundance to the intersample variability in protein abundance estimates in this highly peptide-centric technology. First, the performance of popular quantitative proteomics software, Proteome Discoverer, Scaffold, MaxQuant, and Progenesis QIP, was benchmarked using their default parameters and some modified settings. Beyond this, the intersample variability in protein abundance estimates was decomposed into variability introduced by the entire technology itself and variable protein amounts inherent to individual plants of the Arabidopsis thaliana Col-0 accession. The technical component was considerably higher than the biological intersample variability, suggesting an effect on the degree and validity of reported biological changes in protein abundance. Surprisingly, the biological variability, protein abundance estimates, and protein fold changes were recorded differently by the software used to quantify the proteins, warranting caution in the comparison of discovery proteomics results. As expected, ∼99% of the proteome was invariant in the isogenic plants in the absence of environmental factors; however, few proteins showed substantial quantitative variability. This naturally occurring variation between individual organisms can have an impact on the causality of reported protein fold changes.
Publikation
Otto, A.; Porzel, A.; Westermann, B.; Brandt, W.; Wessjohann, L.; Arnold, N.;Structural and stereochemical elucidation of new hygrophorones from Hygrophorus abieticola (Basidiomycetes)Tetrahedron731682-1690(2017)DOI: 10.1016/j.tet.2017.02.013
Four new hygrophorones (1–4) together with the known hygrophorone B12 (5) have been isolated from fruiting bodies of the basidiomycete Hygrophorus abieticola Krieglst. ex Gröger & Bresinsky. Their structures were assigned on the basis of extensive one and two dimensional NMR spectroscopic analyses as well as ESI-HRMS measurements. Among these compounds, two previously undescribed hygrophorone types, named hygrophorone H12 (3) and 2,3-dihydrohygrophorone H12 (4), were identified. The absolute configuration of hygrophorone E12 (2) is suggested based on quantum chemical CD calculations, while a semisynthetic approach in conjunction with computational studies and analysis of NOE interactions allowed the stereochemical assignment of compounds 3 and 4. Additionally, semisynthetic derivatives of hygrophorone B12 (5) were generated by acetylation of the hydroxyl groups. The biological activity of the natural and semisynthetic hygrophorones was evaluated against phytopathogenic organisms, revealing that the α,β-unsaturated carbonyl functionality is likely to be an essential structural feature. Hygrophorone B12 (5) was identified as the most active compound, acting against both ascomycetous fungi and oomycetes.