CAROTENOIDS 



Lonnberg* in his general survey of carotenoids in marine inverte- 

 brates noted carotenoids in a schizopod, Mysis flexuosa, an isopod, 

 Idothea baltica, two amphipods, Haploops tubicola and Neohela mon- 

 strosa ; and in the cirripeds, Balanus halanus and Scalpellum scalpellum. 

 The gonads of the cirripeds Lepas fascicularis and L, anatifera contain 

 astaxanthin. ^ ^ The amphipods, Orchestia gammarelus^ and Gammarus 

 marinus contain astaxanthin. ® ^ (See also Table 28.) 



Wagner *^^ has claimed to have isolated crystalline p-carotene in 

 large amounts from the mixed krill obtained from the stomachs of 

 whales. 



The recent work of Kon and his colleagues, ^^^'^•^' however, con- 

 firms the impression that p-carotene is a very minor component of 

 crustacean carotenoids. They found only traces of this pigment in 

 Meganyctiphanes norvegica, Thysanoessa raschii, Pandalus bonnieri, 

 Spirontocarm spinus, Crangon allmanni and C. vulgaris, whilst astaxan- 

 thin occurred in large amounts. As these species are typical of a mixed 

 "krill", this investigation suggests that Wagner ^*^ was almost 

 certainly mistaken in identifying his carotenoid as p-carotene. As 

 Moore *^^ points out, however, *' . . . in view of Goodwin's observa- 

 tions on astaxanthin and ^-carotene in locusts [see p. 225), it might be 

 unwise at the moment to discredit completely Wagner's claim ". 



It is on the decapods that most of the work has been carried out. 

 A pigment, presumably astaxanthin, was first obtained from the lobster 

 by Pouchet in 1872. Other early workers (see Lederer ^ for full refer- 

 ences) found two pigments : 



(1) red, with one absorption band (astaxanthin) variously named 

 crustaceorubin, zooerythrin, tetronerythrin, and vitellorubin. 



(2) yellow, with 3 absorption bands, presumably a neutral xantho- 

 phyllic carotenoid called vitellolutein. 



Lonnberg* and Verne ^^'^^ reported carotenoids in the eyes, blood, 

 carapace and hypodermal chromatophores of a number of decapods. 

 Modern qualitative investigations were however initiated by Kuhn 

 and Lederer,** who found that the green chromoprotein (ovoverdin) 

 of the eggs of the spring lobsters (Homarus vulgaris) broke down to 

 liberate *' astacin.'* It was also found in the hypodermis, ovaries and 

 blood and it now appears to be universally distributed in Crustacea 

 (see Table 28). Astacin was first obtained crystalline from the eggs of 

 Maja squinado * »» '^ » and is 3 : 4, 3' : 4'-tetra-keto-;3-carotene. (Fig. 24.) 



[3-carotene also exists in these eggs in small amounts (between 2-5 

 and 20 per cent, of the astaxanthin present). It is, however, completely 

 absent from lobster eggs. ^^^ 



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