Measuring the production of marine phytoplankton

Die Carotinoide der Thiorhodaceae: I. Okenon als Hauptcarotinoid von Chromatium okenii Perty

Tables for the identification of carotenoid pigments.

Publisher Summary This chapter discusses the quantitative determination of carotenoids in photosynthetic tissues. A useful separation of carotenoid pigments into nonpolar carotenes and carotenoid esters in one group, and polar xanthophylls (containing hydroxyl groups) in the other may be accomplished by partitioning the pigments between petroleum ether and aqueous methanol. This can be done by dissolving the extract in aqueous methanol in a separatory funnel and adding an equal amount of petroleum ether. In cases where the carotenoid components are stable toward alkali, it is advantageous to include saponification in the isolation procedure for removing chlorophyll and other saponifiable matter. The pigment is taken to dryness (oil pump); all acetone must be removed from the extract to avoid base-catalyzed formation of condensation products of acetone. The residue is dissolved in a small volume of ether, and the same volume of 10% methanolic KOH solution is added. The approximate content of total carotenoids in an extract may be determined by measuring the optical density of a sample suitably diluted.

[56] Quantitative determination of carotenoids in photosynthetic tissues

Chromatium warmingii enthalt auser Lycopin und Rhodopin drei weitere bisher nicht beschriebene Carotinoide. Das eine (Pigment 3) mit Lycopin-Chromophor ist wahrscheinlich ein Hydroxy-Derivat von Rhodopin (1,2-Dihydro-1-OH-Lycopin); die zweite Hydroxylgruppe ist sekundar. Die sehr ahnlichen Spektren der beiden anderen gehoren zu dem verschwommenen Typus der Keto-Carotinoide. Das Hauptcarotinoid, das zu 73% der Gesamtcarotinoide enthalten war, wurde Warmingon (Pigment 2) genannt. Warmingon, liefert bei LiAlH4-Reduktion Pigment 3. Die fur die vorhandenen Carotinoide nachgewiesenen engen chemischen Beziehungen deuten auf ihre biosynthetische Verwandtchaft hin.

L. Zechmeister

Papers

Determination of Partition Coefficients of Carotenoids as Tool in Pigment Analysis