Sammendrag
Abstract: Cyanobacteria produce a large number
of bioactive oligopeptides with yet unknown
functions. Here the effect of environmental factors
on the production of two anabaenopeptins
and a microviridin by Planktothrix agardhii was
investigated. The results were compared with
previous findings on the production of a third
family of oligopeptides, the highly toxic microcystins,
to test the hypothesis that environmental
factors affect the production of different types of
cyanobacterial bioactive oligopeptides in a similar
manner. Despite marked changes in culture
conditions, variations in the amount of cell-bound
anabaenopeptins and microviridin I per biomass
unit did not exceed a factor of 5. High amounts of
cell-bound anabaenopeptins and microviridin I
per Planktothrix biovolume were associated with
a high availability of nitrogen and phosphorus.
The production of anabaenopeptins and microviridin
continued as long as the Planktothrix
cultures grew. In all cases the oligopeptide net
production rate was linearly correlated to the
growth rate of Planktothrix, identifying the
growth activity as a major regulator of anabaenopeptin
and microviridin production. The concentration
of anabaenopeptins and microviridins
in nature may therefore be estimated from the
biomass concentration of their producers. These
findings are similar to those previously reported
for microcystins and thus support the idea that
different types of bioactive cyanobacterial oligopeptides
may share common regulation patterns.
This may be seen as a hint to a mutual function of
cyanobacterial oligopeptides, although further
studies are needed to draw final conclusions on this issue.
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