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Publications - Cell and Metabolic Biology
Publications
Plants have developed a robust transcription machinery to combat potential pathogenic organisms. One of the hallmarks of early immune responses is the activation of the WRKY transcription factors post infection. Specific WRKYs proteins from Arabidopsis are known substrates of MAPK pathway to mediate the flg22 elicited early immunity. In the current study, using the Golden Gate cloning strategy, we aim to clone the entire WRKY transcription factor family from Oryza sativa ssp. indica consisting of more than 100 members and study their MAPK interaction and subsequent role in PTI. Using a reporter LUC assay in protoplasts we investigated the early defense responses in a few interesting OsWRKY candidates. Interestingly, we observed stringent regulation of WRKY expression in cells and their transcriptional expression only under specific stress responses. The phenomenon of gene expression regulation by intron retention (IR) was prevalently observed in rice WRKY transcripts. We could show the role of WRKY8, 24, and 77 in early defense responses. It was observed that WRKY24 enhanced the expression of early defense response marker genes like NHL10 while WRKY8 and WRKY77 supressed their expression. This study highlights the complicated mechanism by which OsWRKYs expression is possibly regulated and the distinctive roles of some individual members in plant immunity. At the same time this study serves as a cautionary warning for plant researchers to be mindful of the intron retention mechanism while cloning OsWRKYs.
Publications
Developing new biopolymer-based materials with bio-identical properties is a significant challenge in modern science. One interesting route to this goal involves the biomineralization of collagen, a pre-structured and widely available protein, into a material with interesting properties. A prerequisite for biomineralization is the ability of cations (e.g., calcium) to bind to the protein and to result in concert with appropriate anions (e.g., phosphate) in composite material with e.g., bone-like properties. In order to increase the number of binding sites it is necessary to modify the protein prior to mineralization. For this glucuronic acid (GA) was used due to its carbonyl and carboxyl groups to derivatize proteinogenic amino groups transferring them into negatively charged carboxyl groups. Our experiments showed for the first time, that Nɛ-carboxymethyllysine is the major product of in vitro non-enzymatic glycosylation of collagen by glucuronic acid. For an unequivocal determination of the reaction products, the lysine residues of collagen and of the model peptide were carboxymethylated through a reductive alkylation with glyoxalic acid and compared to the glucuronic acid derivatives. Beside their identical mass spectra the common structure elements could be confirmed with FTIR. Thus, in the context of matrix engineering, by producing Nɛ-carboxymethyllysine, glucuronic acid offers a convenient way of introducing additional stable acidic groups into protein matrices.
Publications
The induction of chitinase (CAChi2) mRNA started as early as 6 h after inoculation and gradually increased in the incompatible interaction of pepper stems with Phytophthora capsici. In the compatible interaction, the induction of the chitinase transcripts was detected later than that in the incompatible interaction. The CAChi2 mRNA was usually localized in the vascular tissues and their expression was constricted in the phloem-related cells. These results showed that the spatial pattern of CAChi2 mRNA expression was similar in both compatible and incompatible interactions but the temporal patterns were different from each other. In addition, the early induction ofCAChi2 mRNA was quite distinct in the incompatible interaction. Immunogold labelling data showed specific labelling of chitinase on the cell wall of the oomycete in both compatible and incompatible interactions at 24 h after inoculation. In particular, numerous gold particles were deposited on the cell wall of P. capsici with a predominant accumulation over areas showing signs of degradation in the incompatible interaction. Chitinase labelling was also detected in the intercellular space and the host cytoplasm. However, healthy pepper stem tissue was nearly free of labelling.
This page was last modified on 27 Jan 2025 .
