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|Title: ||Effects of tryptamine on growth, ultrastructure, and oxidative stress of cyanobacteria and microalgae cultures|
|Authors: ||Churro, C.|
Fernandes, A. S.
Figueira, V. C.
Bento, A. J.
Lobo, A. M.
Martins, L. L.
Mourato, M. P.
Água e Solo
|Issue Date: ||Jul-2010|
|Citation: ||Hydrobiologia 2010 Jul;649(1):195-206|
|Abstract: ||Tryptamine was screened for selective
antialgal activity against different cyanobacteria and
eukaryotic microalgae. In a rapid 96-well microplate
bioassay cultures were exposed to tryptamine concentrations
from 0.625 to 20 lg ml-1 and growth
was estimated by daily optical measurements over a
216 h period. Inhibitory concentrations (IC50216h)
obtained from the sigmoidal inhibition curves
showed that tryptamine prevents the growth of most
cyanobacteria and eukaryotic microalgae at similar
concentrations. However, most of the eukaryotic
algae recovered growth after being transferred to new tryptamine-free culture media, while most
cyanobacteria showed no growth recovery. Microscopical
examination of exposed cells showed no
major effects of tryptamine on eukaryotic ultrastructure
but showed major-induced alterations on cyanobacteria
(disorganization of thylakoid membranes,
intratylakoidal vacuolization, increased cytoplasmatic
granules, and cell lysis). Biochemical analyses
performed on Aphanizomenon gracile (cyanobacteria)
and Ankistrodesmus falcatus (chlorophyceae)
showed that tryptamine induces an increase in H2O2
production in both cultures. Although no significant
changes in catalase activity were detected, both
cultures showed an increase in ascorbate peroxidase
activity following tryptamine exposure treatments.
Interestingly, lipid peroxidation was found to
increase only in A. gracile, suggesting that the
cellular defence mechanisms triggered by this cyanobacterium
were less efficient than the ones
triggered by A. falcatus for the removal of reactive
oxygen species (ROS). Strong lipid peroxidation in
cyanobacteria might lead to irreversible membrane
damages which probably prevent these organisms to
recover growth after tryptamine exposure. On the
contrary, the eukaryotic alga seems to respond quite
effectively to tryptamine induced oxidative stress and
this would explain the capacity for this organism to
recover growth after being exposed to tryptamine.|
|Peer Reviewed: ||yes|
|Publisher version: ||http://www.springerlink.com/content/1nr3701637367203/|
|Appears in Collections:||DSA - Artigos em revistas internacionais|
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