American cockroach (Periplaneta americana) synthesizes carotenoids from the precursor.

摘要: The level of an important carotenoid (β-carotene) in the gut Periplaneta americana depends on content food: a carotenoid-fortified diet causes accumulation β-carotene up to 10 μg/g wet weight, while carotenoid-deficient this substance is low (∼0.7 weight). In eye, contrast gut, constant (1.3-1.4 weight) found regardless diet. This phenomenon remained unchanged over three years feeding cockroaches with diet, suggesting that P. produces carotenoids by de novo biosynthesis. suggestion was confirmed experiments using intraperitoneal injection exogenous biosynthesis precursor [14C]mevalonic acid pyrophosphate followed extraction and chromatographic purification labeled product. Injection 3.4 nmoles transiently increased eyes days 2 4 after label. Purification radiolabeled from eye transfer into less polar solvent, alkaline hydrolysis (saponification), chromatography alumina cellulose columns decreased specific radioactivity cannot be further repeated chromatography. elution profile these purified preparations characterized coincidence symmetric peaks count absorption. We suggest create optimal concentration uses two biochemical mechanism: 1) it accumulates reserve when abundant supplies are available diet; 2) synthesizes its food deficient compounds.