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SLOT | Aims

Subcellular location of microcystins and anabaenopeptides.

It has been suggested that the Adda moiety of the microcystins binds to membranes because of the lipohilic nature. In fact, a structural variety of microcystins, nodularin  has been reported to form pores in lipid bilayers and native membranes. Further, using immune-gold labeling techniques the majority of the microcystins have been detected surrounding the thylakoid area. Furthermore proteomic assays have confirmed covalent linkage between microcystins and abundant proteins such a phycobiliproteins and Rubisco. Since thylakoid structures can be visualized through autofluorescence and distinguished from chemically labeled peptides we can investigate the location of the peptides more directly using advanced imaging. Using higher microscopic resolution will further help to find possible in vivo compartmentation, or if the peptides are located in the cytoplasm or the periplasmic space.

 

Intercellular variation of microcystin/anabaenopeptin synthesis.

It has been shown that  the gene cluster of microcystin synthesis is prone to transposase driven mutations (insertions or deletions), thus altering the microcystin synthesis at a cellular level. Analogously mutations have been found for the gene cluster encoding anabaenopeptin synthesis. The chemical labelling techniques can be a prominent tool to detect and quantify the variability of the different peptide signal among the cells and genotypes.

 

In vivo observation of intracellular microcystin and anabaenopeptide pool and its potential release.

Previously the intra and extracellular distribution of peptides has been studied using strains, revealing significant difference between the intra and extracellular content of peptides. It is speculated that the strains with higher extracellular peptide content are actively exporting or show other specific difference in cell wall permeability. We will investigate active or passive transport processes by imaging chemically labeled peptides using microscopy, flow-cytometry, and LC-MS quantification.

 

In vivo observation of the fate of intracellular peptides during physiological stress conditions.

It is known that the physiological stress affects the allelopathy in many different organisms. Using chemical labeling we aim to differentiate the effects of contrasting physiological growth conditions of the intracellular peptides and their release.