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You are here: Home Events September 12, 2018: Rainer Kurmayer, University of Innsbruck

September 12, 2018: Rainer Kurmayer, University of Innsbruck

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Talk in the biologic colloquium: "Molecular ecophysiology of cyanoHABs: State of the art and research topics"

What
  • Biologisches Kolloquium
When Sep 12, 2018
from 02:15 PM to 03:30 PM
Where Lecture Hall, Zoology, Hauptstr. 1
Contact Name
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Abstract

Economic losses because of harmful algal blooms formed by cyanobacteria (cyanoHABs) occur due to deterioration of ecosystem service provision. Costs increase because of managing and treating recreation and drinking water supplies. The transfer of cyanobacterial toxins (cyanotoxins) in the food chain is of concern since human nutrition partly depends on freshwater resources which suffer from cyanoHABs. A major step in the molecular understanding of cyanotoxin synthesis has been derived from isolated strains. Working with clonal strains is considered essential in order to understand metabolic pathways and an overview on the current understanding of cyanotoxin synthesis will be provided.

For cyanobacteria genera such as Planktothrix, by using a larger number of isolated strains the influence of phylogeny, ecophysiological adaptation and geographic distance on toxin distribution could be demonstrated. This phylogenetic approach not only includes cyanotoxins per se but also secondary metabolite synthesis related to cyanotoxins (bioactive peptides). Knowing the genetic basis of non-ribosomal peptide synthesis (NRPS) the secondary metabolite synthesis and its regulation is studied in cultures using chemical-analytical methods.

In general ecophysiological variation in cyanotoxin/bioactive peptide production has been studied using strain cultures under laboratory conditions by calculating cyanotoxin/bioactive peptide cell quotas which are used for comparison. This approach ignores the variability on the individual cell level which is induced for example by transposable elements. One possibility to quantify cyanotoxins on the individual cell level is by so-called bioorthogonal labelling. In vivo labelling of cyanotoxins/peptides is based on the discovery of unspecific (promiscuous) adenylation domains part of NRPS which also can use non-natural functional groups as precursors (e.g. amino acid alkynes). The resulting alkyne-modified molecule is subsequently labelled by an azide-modified fluorophore through a copper-catalyzed click chemistry reaction. Sensitive in vivo techniques such as laser scanning confocal microscopy are then used to analyze cyanotoxin/peptide distribution both on the intercellular and intracellular level.

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