0000000001001629
AUTHOR
Stefan Zauner
Ancient recruitment by chromists of green algal genes encoding enzymes for carotenoid biosynthesis.
Chromist algae (stramenopiles, cryptophytes, and haptophytes) are major contributors to marine primary productivity. These eukaryotes acquired their plastid via secondary endosymbiosis, whereby an early-diverging red alga was engulfed by a protist and the plastid was retained and its associated nuclear-encoded genes were transferred to the host genome. Current data suggest, however, that chromists are paraphyletic; therefore, it remains unclear whether their plastids trace back to a single secondary endosymbiosis or, alternatively, this organelle has resulted from multiple independent events in the different chromist lineages. Both scenarios, however, predict that plastid-targeted, nucleus-…
Reverse paintings on glass--a new approach for dating and localization.
Samples from 20 reverse paintings on glass from different regions have been analyzed by NAA with the aim to deduce the place and date of their origin. A separation of earlier and later paintings was due to different concentrations of K and Na, because a sodium-containing flux came into use after 1870. Since in southern Germany quartz sand, and in the eastern area quartz rock had been used for glass manufacture, specific impurities could be used to distinguish southern from eastern glasses.