Department of Bioorganic Chemistry
Research topics of the Bioorganic Chemistry
Department
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The Lima bean (Phaseolus lunatus) reacts upon
different types of stress such as wounding, herbivory and pathogenesis with
distinct defense mechanisms. These reactions are initiated by high- and low-molecular
elicitors.
We investigate the plant signaling and defense processes concentrating on
the analysis and quantification of volatile production and
phytohormone
levels. In parallel potential elicitors are characterized and synthesized.
Additionally we perform field experiments to
analyzes the ecological relevance of the indirect defense of the Lima bean. |
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The oral secretion of herbivores are believed to play a major role for the plant
herbivore recognition and initiation of plant defense. We investigate elicitors
of lepidopteran larvae such as the N-acylamino acids.
Low and high molecular weight compounds are isolated and characterized. The structure
elucidation and synthesis of bioactive
compounds from oral secretions is the key for a thorough understanding of
the mechanisms involved in plant herbivore interactions, their involvement in the insects metabolism,
their biosynthesis and ecology. |
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With 350,000 described beetle species Coleoptera is the largest order of
life on Earth. Members of the family of Chrysomelidae occur widespread all over the world.
These phytophagous insects are threatened by a lot of different
animals like mammals, birds and other insects, and have developed different
mechanical and chemical strategies to defend themselves.
We are interested how larvae relying on chemical defense could develop
new defensive compounds. We try to explain the ecological and evolutionary
origins and consequences of de novo synthesis and sequestration of defensive compounds. |
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Terpenoids are vital for life of most organisms in exerting metabolic
control and in mediating intra- and inter-species interactions. In plants
two different pathways synthesize the main building block isopentenyl
diphosphate (IPP): The methylerythritolphosphate (MEP) pathway and the
mevalonic acid (MVA) pathway. To examine the distribution of both pathways,
we use labeled precursors or measure the natural 13C/12C
isotope ratios of terpenoids. In collaboration with the Biochemistry
Department, we synthesize labeled precursors to elucidate enzyme
mechanisms involved in terpenoid biosynthesis. |
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Desaturases are omnipresent iron containing enzymes which introduce double
bonds mainly into fatty acids or related compounds. As an example
desaturases are involved in the biosynthesis of essential fatty acids or the
production of sex pheromones of many insects.
We try to elucidate mechanistical aspects of unusual desaturases derived from
animals and plants. Extensively using synthetic enantiospecific labeled
precursors in combination with molecular biological techniques we are able
to probe the mechanism of these desaturases.
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Zygomycetes are a group of soil fungi with
ubiquitous appearance. Within this class of fungi sexual and parasitic
interaction occurs. The intra- and inter-specific communication of zygomycetes is controlled by pheromones. These trisporoids only found in
some zygomycetes, are degradation products of ß-carotene and function as
sexual communication signals. Our aim is to clarify molecular mechanisms of
this fungal communication system and analyze the ecological aspect how
zygomycetes of different species recognize each other. |
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The brown algae or Phaeophyceae represent an important group of eukaryotes
due to their position in the tree of life. Ectocarpus
siliculosus, a small filamentous alga is currently developed as a model
organism to investigate on a functional level the particular characteristics
of the Phaeophyceae. The life cycle of Ectocarpus has been
extensively studied in culture experiments revealing a sexual life cycle
with alternating diploid (sporophyte) and haploid (gametophyte) stages. The
female gametes attract, after settlement, the male gametes through the
secretion of a pheromone. We investigate the chemical signaling related to
the sexual reproduction of Ectocarpus. We are also interested in several
aspects of the life cycle of Ectocarpus siliculosus virus-1 (EsV-1) of which
its replication is also dependent on Ectocarpus’ reproduction. |
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