U5 - 



columns of sugar and in columns of magnesia, but it is converted to 

 siphonaxanthin by alkalies whereas fucoxanthin is destroyed, 



"When n=propanol solutions of siphonaxanthin and siphonein are 

 heated, the absorption in the green region of the spectrum decreases 

 relative to that in the blue. This is due to the formation of spa- 

 tially isomeric pigments (neo isomers '■^s'^^) that have been isolated 

 by chromatographic adsorption. The characteristic spectra of these 

 isomers compared to the parent pigments is shown in Figure 11,7, 



Supplemental Carotenoid Pigments of Green Algae 



Some of the green algae have long been known to lose their green 

 color and to become yellow when exposed to various unfavorable condi- 

 tions such as dehydration, lack of nutrients and high salt concentra- 

 tiono This phenomenon has frequently been ascribed to the development 

 of a secondary pigment, "haematochrome". In some species, as Dunaliella 

 salina and Chlorella vulgaris , haematochrome has proved to be P-caro- 

 tene-^j9„ 



Like so many green algae, Proto siphon botryoides (Chlorocoocales) 

 (Appendix IV) is also known to turn yellow to red when the cultures on 

 agar are allowed to dry out. These red organisms have been found to 

 yield two unusual carotenoid pigments that replace the green and yellow 

 pigments of the green organisms, (See Figure 11,1 and Appendix IV,) 

 In columns of powdered sugar these two pigments were weakly sorbed 

 forming purple-orange zones. They were separated readily by washing 

 the sugar colimns with petroleum ether plus 2 per cent acetone. The 

 spectral absorption curves are shown in Figure 11,8, In columns of 

 sugar and with petroleum ether plus 0,5 per cent n-propanol as wash 



