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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

Rekik, I.; Drira, N.; Grubb, C. D.; Elleuch, A.; Molecular characterization and evolution studies of a SERK like gene transcriptionally induced during somatic embryogenesis in Phoenix Dactylifera L v Deglet Nour Genetika 47, 323-337, (2015) DOI: 10.2298/GENSR1501323R

A somatic embryogenesis receptor kinase like (SERKL) cDNA, designated PhSERKL, was isolated from date palm (Phoenix Dactylifera L) using RACE PCR. PhSERKL protein shared all the characteristic domains of the SERK family, including five leucine-rich repeats, one proline-rich region motif, a transmembrane domain, and kinase domains. Phylogenetic analyses using PHYLIP and Notung 2.7 programs suggest that the SERK proteins of some plant species resulted from relatively ancient duplication events. We predict an ancestor protein of monocots and dicots SERK using FASTML program. Somatic embryogenic cultures of date palm were established following transfer of callus cultures to medium containing 2, 4-dichlorophenoxyacetic acid. The role of PhSERKL gene during establishment of somatic embryogenesis in culture was investigated using quantitative real-time PCR. PhSERKL gene was highly expressed during embryogenic competence acquisition and globular embryo formation in culture. Overall, levels of expression of PhSERKL gene were lower in nonembryogenic tissues and organs than in embryogenic callus.
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).
Publikation

Quint, M.; Melchinger, A. E.; Dußle, C. M.; Lübberstedt, T.; Breeding for virus resistance in maize Genetika 32, 529-545, (2000)

Sugarcane mosaic virus (SCMV) is an important disease in maize, which is emerging in Germany since 1983. Using this pest as a model for the inheritance of oligogenic traits, we clarified the genetic ba­sis for resistance in early maturing European maize germplasm. Screening of 122 adapted European inbred lines identified three completely resistant lines, which were used for further analyses. The genetics of SCMV resis­tance was investigated by allelism tests in field experiments combined with QTL and bulked segregant analyses (BSA) on the marker level. QTL analyses revealed the presence of two major genes Scm1 and Scm2 plus three minor QTL. Involvement of Scm1 and Scm2 in the inheritance of SCMV resistance could be confirmed by BSA in a second cross. Breeders can make use of tightly linked STS markers for marker-assisted selection (MAS) as well as our SCMV resistant flint lines to improve their elite germplasm. Currently, recurrent backcrossing with phenotypic selection is the most appropriate and cost effective breeding method. With de­creasing costs of DNA chip technology, MAS can be competitive with phenotypic selection in the near future. Further objectives of our research are the isolation and cloning of Scm1 and Scm2. To achieve this goal we follow two different approaches. (1) Positional cloning based on more than 500 AFLP primer combinations resulted in Scm1/Scm2 specific markers with a resolution of approximately 0.2 cM in the respective re­gions. (2) Resistance gene analogues (RGAs), cosegregating with the tar­get genes are used to identify further candidate genes for transformation experiments.
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