Does toxic defence in Nycticebus spp. relate to ectoparasites? The
lethal effects of slow loris venom on arthropods
Nanda B.Extremophilic green algae and cyanobacteria are the most abundant species in high mountain habitats,
where rough climate conditions such as temperature differences, limited water retention and high ultraviolet
(UV) radiation are the cause for a restricted biological diversity in favor of a few specialized autotrophic
microorganisms. In this study, we investigated four algal species from alpine habitat in a sun
simulator for their defense strategies in response to UV-A radiation (315–400 nm) up to 13.4 W/m2
and UV-B radiation (280–315 nm) up to 2.8 W/m2. Besides changes in pigment composition we discovered
that primary polar metabolites like aromatic amino acids, nucleic bases and nucleosides are increasingly
produced when the organisms are exposed to elevated UV radiation. Respective compounds were
isolated and identified, and in order to quantify them an HPLC-DAD method was developed and validated.
Our results show that especially tyrosine and guanosine were found to be generally two to three times
upregulated in the UV-B exposed samples compared to the non-treated control.