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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

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

Hause, B.; Feussner, K.; Wasternack, C.; Nuclear Location of a Diadenosine 5′,5′”-P1,P4Tetraphosphate (Ap4A) Hydrolase in Tomato Cells Grown in Suspension Cultures Bot. Acta 110, 452-457, (1997) DOI: 10.1111/j.1438-8677.1997.tb00662.x

Diadenosine 5′,5′”‐P1,P4‐tetraphosphate (Ap4A) cleaving enzymes are assumed to regulate intracellular levels of Ap4A, a compound known to affect cell proliferation and stress responses. From plants an Ap4A hydrolase was recently purified using tomato cells grown in suspension. It was partially sequenced and a peptide antibody was prepared (Feussner et al., 1996). Using this polyclonal monospecific antibody, an abundant nuclear location of Ap4A hydrolase in 4‐day‐old cells of atomato cell suspension culture is demonstrated here by means of immunocytochemical techniques using FITC (fluorescein‐5‐isothiocyanate) labeled secondary antibodies. The microscopic analysis of the occurrence of Ap4A hydrolase performed for different stages of the cell cycle visualized by parallel DAPI (4,6‐diamidino‐2‐phenylindole) staining revealed that the protein accumulates within nuclei of cells in the interphase, but is absent in the nucleus as well as cytoplasm during all stages of mitosis. This first intracellular localization of an Ap4A degrading enzyme within the nucleus and its pattern of appearance during the cell cycle is discussed in relation to the suggested role of Ap4A in triggering DNA synthesis and cell proliferation.
Publikation

Feussner, I.; Fritz, I. G.; Hause, B.; Ullrich, W. R.; Wasternack, C.; Induction of a new Lipoxygenase Form in Cucumber Leaves by Salicylic Acid or 2,6-Dichloroisonicotinic Acid Bot. Acta 110, 101-108, (1997) DOI: 10.1111/j.1438-8677.1997.tb00616.x

Changes in lipoxygenase (LOX) protein pattern and/or activity were investigated in relation to acquired resistance of cucumber (Cucumis sativus L.) leaves against two powdery mildews, Sphaerotheca fuliginea (Schlecht) Salmon and Erysiphe cichoracearum DC et Merat. Acquired resistance was established by spraying leaves with salicylic acid (SA) or 2,6‐dichloroisonicotinic acid (INA) and estimated in whole plants by infested leaf area compared to control plants. SA was more effective than INA. According to Western blots, untreated cucumber leaves contained a 97 kDa LOX form, which remained unchanged for up to 48 h after pathogen inoculation. Upon treatment with SA alone for 24 h or with INA plus pathogen, an additional 95 kDa LOX form appeared which had an isoelectric point in the alkaline range. For the induction of this form, a threshold concentration of 1 mM SA was required, higher SA concentrations did not change LOX‐95 expression which remained similar between 24 h and 96 h but further increased upon mildew inoculation. Phloem exudates contained only the LOX‐97 form, in intercellular washing fluid no LOX was detected. dichloroisonicotinic localization revealed LOX protein in the cytosol of the mesophyll cells without differences between the forms.
Publikation

Hause, B.; zur Nieden, U.; Lehmann, J.; Wasternack, C.; Parthier, B.; Intracellular Localization of Jasmonate-Induced Proteins in Barley Leaves Bot. Acta 107, 333-341, (1994) DOI: 10.1111/j.1438-8677.1994.tb00804.x

The plant growth substance jasmonic acid and its methyl ester (JA‐Me) induce a set of proteins (jasmonate‐induced proteins, JIPs) when applied to leaf segments of barley (Hordeum vulgare L. cv. Salome). Most of these JIPs could be localized within different cell compartments by using a combination of biochemical and histochemical methods. Isolation and purification of various cell organelles of barley mesophyll cells, the separation of their proteins by one‐dimensional polyacrylamide gel electrophoresis and the identification of the major abundant JIPs by Western blot analysis, as well as the immuno‐gold labelling of JIPs in ultrathin sections were performed to localize JIPs intracellularly. JIP‐23 was found to be in vacuoles, peroxisomes, and in the granular parts of the nucleus as well as within the cytoplasm; JIP‐37 was detected in vacuoles and in the nucleoplasm; JIP‐66 is a cytosolic protein. Some less abundant JIPs were also localized within different cell compartments: JIP‐100 was found within the stromal fraction of chloroplasts; JIP‐70 is present in the peroxisome and the nucleus; JIP‐50 and JIP‐6 accumulate in vacuoles. The location of JIP‐66 and JIP‐6 confirms their possible physiological role deduced from molecular analysis of their cDNA.
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