Biomedical subjects

Bernhard Schlesier

Publications and source records attributed to Bernhard Schlesier.

5 recordsLinked to original sources

PubMed2006

cDNA sequences, MALDI-TOF analyses, and molecular modelling of barley PR-5 proteins.

Barley plants are known to produce various PR-5 proteins. Transcripts encoding eight different barley PR-5 proteins (TLPs 1-8, TLP for thaumatin-like protein) were identified and cloned - seven from infected leaves and one from developing grains. Here, we describe the cDNA sequences of four of these TLP isoforms. Moreover, the TLPs from the infected leaves (TLPs 1, 2, and TLPs 4-8) were subjected to MALDI-TOF mass spectrometric measurements that resulted in protein fragments consistent with their deduced peptide sequences. Multiple sequence alignment analysis revealed that the TLPs in barley fall into two groups: long-chain proteins (TLPs 5-8) having 16 cysteine residues and short-chain proteins (TLPs 1-4) with only 10 cysteine residues. Finally, modelling experiments highlighted the effects of sequence differences between the TLP isoforms in terms of their secondary structures and their molecular electrostatic potentials. We propose that these sequence differences have implications for the target preferences of the different isomers.

Amino Acid Sequence↗

PubMed2006

Proteome analysis of cold stress response in Arabidopsis thaliana using DIGE-technology.

A proteome study based on 2-D gel electrophoresis was performed in order to analyse the cold-stress response of Arabidopsis plants. The emphasis was to monitor the overall changes in the protein complement after prolonged exposure rather than short-term responses. Two different temperature regimes were used (6 degrees C and 10 degrees C) and plants were exposed to cold-stress exposure for 1 week. Protein patterns were also monitored after re-shifting plants to control conditions for a further week. To monitor gradual changes in the response to the two cold-stress conditions, the analysis was performed with DIGE technology with the inclusion of an internal standard. In the experiments using 6 degrees C, 22 spots with at least 2-fold altered expression were found; among them 18 were increased and four were decreased. When plants were exposed to 10 degrees C, 18 of these 22 spots still showed a 2-fold change; however, the alterations were, in general, more moderate than observed under 6 degrees C. Spot identification was performed by MALDI-TOF and ESI-MS/MS. Many of the proteins identified have previously been described in the context of cold-stress responses, indicating the validity of this proteome approach for further in-depth studies.

Arabidopsis↗

PubMed2006

Protein isolation and second-dimension electrophoretic separation.

Protocols for the proteome analysis of Arabidopsis tissues based on 2 D gel electrophoresis are given for leaves and roots as well as for seeds. The protocols contain a detailed description of the sample preparation step and of the solubilization of proteins. We then describe our protocols for the isoelectric focusing, the transfer of the strips from the first to the second dimension, SDS-PAGE as the second dimension of electrophoretic separation, staining of the gels using colloidal Coomassie blue, and finally drying of the gels between cellophane sheets. Notes contain additional background information on critical steps. Our protocols allow the analysis of leaves, roots, or seeds from different Arabidopsis ecotypes, from mutants or from plants subjected to various environmental conditions.

Arabidopsis↗

PubMed2005

A proteome approach defines protective functions of tobacco leaf trichomes.

The leaf surface of most terrestrial plants is covered with plant hairs called trichomes. These epidermal appendages are thought to contribute to many aspects of plant defense against biotic and abiotic stresses in a variety of species. Trichome development has been intensively studied in Arabidopsis, and the phytochemical composition of trichomes was analyzed in a number of plant species. However, comparatively little is known of the proteins expressed. We therefore initiated a proteome approach to better define the cellular mechanisms operating in plant trichomes using two-dimensional gel electrophoresis to separate proteins of whole leaves and isolated trichomes. Tobacco was chosen due to the presence of glandular trichomes involved in the secretion of defense compounds. Comparative image analysis of the protein patterns indicated a number of spots, which were highly enriched in trichomes relative to leaves. These spots were excised for identification by mass spectrometry. The results showed that among the proteins specifically enriched in trichomes, the components of stress defense responses were strongly represented. The high expression of stress-related proteins was verified by Western blotting. Superoxide dismutase isoforms were additionally analyzed by activity staining. Our results demonstrate feasibility of the proteome approach to elucidate the cell biology of plant trichomes.

Amino Acid Sequence↗

PubMed2004

Proteome analysis differentiates between two highly homologues germin-like proteins in Arabidopsis thaliana ecotypes Col-0 and Ws-2.

A proteome approach based on 2-D gel electrophoresis (2-DE) was used to compare the protein patterns of the Arabidopsis ecotypes Col-0 and Ws-2. In leaf extracts a pair of protein spots were found to be diagnostic for each of the lines. Both pairs of spots were identified as closely related germin-like proteins differing in only one amino acid by using peptide mass finger printing of tryptic digests and by gaining additional data from post-source decay spectra in the MALDI-TOF analysis. Western blot analysis after separation of protein extracts by 2-DE confirmed results from Coomassie blue-stained gels and revealed additional immunoreactive spots for both ecotypes most likely representing dimers of the spots first identified. Western blot analysis and mass spectrometrical identification of the corresponding weakly stained protein in Coomassie blue-stained gels of the ecotype Col-0 also demonstrated for the first time the occurrence of AtGER3 protein in root extracts. Our results demonstrate the capacity of proteome analysis to analyse and distinguish closely related members of large protein families.

Amino Acid Sequence↗