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Publikation

Kahsay, B. N.; Ziegler, J.; Imming, P.; Gebre-Mariam, T.; Neubert, R. H. H.; Moeller, L.; Free amino acid contents of selected Ethiopian plant and fungi species: a search for alternative natural free amino acid sources for cosmeceutical applications Amino Acids 53, 1105-1122, (2021) DOI: 10.1007/s00726-021-03008-5

Free amino acids (FAAs), the major constituents of the natural moisturizing factor (NMF), are very important for maintaining the moisture balance of human skin and their deficiency results in dry skin conditions. There is a great interest in the identification and use of nature-based sources of these molecules for such cosmeceutical applications. The objective of the present study was, therefore, to investigate the FAA contents of selected Ethiopian plant and fungi species; and select the best sources so as to use them for the stated purpose. About 59 different plant species and oyster mushroom were included in the study and the concentrations of 27 FAAs were analyzed. Each sample was collected, lyophilized, extracted using aqueous solvent, derivatized with Fluorenylmethoxycarbonyl chloride (Fmoc-Cl) prior to solid-phase extraction and quantified using Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometric (LC-ESI–MS/MS) system. All the 27 FAAs were detected in most of the samples. The dominant FAAs that are part of the NMF were found at sufficiently high concentration in the mushroom and some of the plants. This indicates that FAAs that could be included in the preparations for the management of dry skin condition can be obtained from a single natural resource and the use of these resources for the specified purpose have both economic and therapeutic advantage in addition to fulfilling customer needs.
Publikation

Ryan, P. T.; Ó’Maoiléidigh, D. S.; Drost, H.-G.; Kwaśniewska, K.; Gabel, A.; Grosse, I.; Graciet, E.; Quint, M.; Wellmer, F.; Patterns of gene expression during Arabidopsis flower development from the time of initiation to maturation BMC Genomics 16, 488, (2015) DOI: 10.1186/s12864-015-1699-6

BackgroundThe formation of flowers is one of the main model systems to elucidate the molecular mechanisms that control developmental processes in plants. Although several studies have explored gene expression during flower development in the model plant Arabidopsis thaliana on a genome-wide scale, a continuous series of expression data from the earliest floral stages until maturation has been lacking. Here, we used a floral induction system to close this information gap and to generate a reference dataset for stage-specific gene expression during flower formation.ResultsUsing a floral induction system, we collected floral buds at 14 different stages from the time of initiation until maturation. Using whole-genome microarray analysis, we identified 7,405 genes that exhibit rapid expression changes during flower development. These genes comprise many known floral regulators and we found that the expression profiles for these regulators match their known expression patterns, thus validating the dataset. We analyzed groups of co-expressed genes for over-represented cellular and developmental functions through Gene Ontology analysis and found that they could be assigned specific patterns of activities, which are in agreement with the progression of flower development. Furthermore, by mapping binding sites of floral organ identity factors onto our dataset, we were able to identify gene groups that are likely predominantly under control of these transcriptional regulators. We further found that the distribution of paralogs among groups of co-expressed genes varies considerably, with genes expressed predominantly at early and intermediate stages of flower development showing the highest proportion of such genes.ConclusionsOur results highlight and describe the dynamic expression changes undergone by a large number of genes during flower development. They further provide a comprehensive reference dataset for temporal gene expression during flower formation and we demonstrate that it can be used to integrate data from other genomics approaches such as genome-wide localization studies of transcription factor binding sites.
Publikation

Ziegler, J.; Abel, S.; Analysis of amino acids by HPLC/electrospray negative ion tandem mass spectrometry using 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) derivatization Amino Acids 46, 2799-2808, (2014) DOI: 10.1007/s00726-014-1837-5

A new method for the determination of amino acids is presented. It combines established methods for the derivatization of primary and secondary amino groups with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) with the subsequent amino acid specific detection of the derivatives by LC–ESI–MS/MS using multiple reaction monitoring (MRM). The derivatization proceeds within 5 min, and the resulting amino acid derivatives can be rapidly purified from matrix by solid-phase extraction (SPE) on HR-X resin and separated by reversed-phase HPLC. The Fmoc derivatives yield several amino acid specific fragment ions which opened the possibility to select amino acid specific MRM transitions. The method was applied to all 20 proteinogenic amino acids, and the quantification was performed using l-norvaline as standard. A limit of detection as low as 1 fmol/µl with a linear range of up to 125 pmol/µl could be obtained. Intraday and interday precisions were lower than 10 % relative standard deviations for most of the amino acids. Quantification using l-norvaline as internal standard gave very similar results compared to the quantification using deuterated amino acid as internal standards. Using this protocol, it was possible to record the amino acid profiles of only a single root from Arabidopsis thaliana seedlings and to compare it with the amino acid profiles of 20 dissected root meristems (200 μm).
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