|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1995 : ¥200,000 (Direct Cost : ¥200,000)
Fiscal Year 1994 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Carotenoids are the most widely distributed class of pigments in nature and have essential biological functions in animals and man, including conversion to vitamin A,enhancement of immune response and protection against disease such as cancer by scavending of oxygen radicals. Since animals cannot synthesize carotenoids, the pigments must be supplemented in the feeds. Thus, the main purpose of this research project is screening and breeding of carotenoid-accumulating yeasts.
(1) Screening of pigmented yeast colonies by visual examination has limited utility and is often not capable of detecting carotenoid-hyper-producing strains. However, visual examination was employed in the first screening in which we obtained approximately 1,500 isolates from natural habitats, such as flowers, fruits, saps, leaves, in Japan.
(2) Pigments were extracted with water-miscible polar organic solvent, acetone, from mechanically disrupted yeast wet-cells, follwed by transferring to petroleum-ether. The extrac
ts were dried up by removal of the solvent under reduced pressure. For identification and quantitative determination of the pigments extracted, absorption spectrometry, thin-layr chromatography (TLC), and highpressure liquid chromatography (HPLC) were employed. The specific absorption coefficient [A (1%/1cm) =E (1%/1cm)] is used to calculate the concentration.
Pigments in the cells of individual strain were usually composed of several kinds of carotenoids ; beta-carotene, lycopene, zeaxanthin, canthaxanthin, astaxanthin and unidentified pigments.
(3) Amount and constituent of carotenoid in the visually color-decreased mutant cells were analyzed in comparison with those in parent cells. The pigments extracted from the mutant cells were similar in amounts, but quite differet in molecular species of constituent carotenoids. Alteration in intracellar locarization of the pigments was observed ; increase in menbrane pigment in mutant cells.
(4) Al^<3+> ions are poisonous due to their inductivity of oxygen radicals. Carotenoids are the scavenger for oxygen radicals. Thus, positive relationship between resistancy toward the radicals and enrichment of carotinoids was examined. Less