α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein...α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein, zeaxanthin and β-cryptoxanthin. β-carotene content was relatively low and extremely low was the amount of α-carotene. Among the 53 cultivars tested, lycopene was detected only in pulp of Cara Cara navel orange. Carotenoid content in both peel and pulp of citrus fruit was the highest in Citrus reticulata Blanco and lowest in Citrus grandis Osbeck. Consequently, as far as the health protection value is considered, fruit of Citrus reticulata Blanco ranks probably higher than other citrus fruits. In fruit of most Citrus reticulata varities, β-cryptoxanthin was the main carotenoid component in pulp and its amount approximated that of lutein in peel. Content of lutein, zeaxanthin and β-cryptoxanthin in peel was about 2.515 times that in pulp on the basis of fresh weight. Thus peel was inferred to be the principal location for the carotenoid stock in citrus fruit.展开更多
β-carotene ketolase and β-carotene hydroxylase encoded by bkt and bch, respectively, are key enzymes required for astaxanthin biosynthesis in Haematococcu pluvialis 34-1n. Two expression vectors containing cDNA sequ...β-carotene ketolase and β-carotene hydroxylase encoded by bkt and bch, respectively, are key enzymes required for astaxanthin biosynthesis in Haematococcu pluvialis 34-1n. Two expression vectors containing cDNA sequences of bkt and bch were constructed and co-transformed into cell-wall-deficient Chlamydomonas reinhardtii CC-849. Transgenic algae were screened on TAP agar plates containing 10 gg mL 1 Zeomycin. PCR-Southern analysis showed that bkt and bch were integrated into the genomes of C. reinhardtii. Transcripts of bkt and bch were further confirmed by RT-PCR-Southern analysis. Compared with the wild type, transgenic algae produced 29.04% and 30.27% more carotenoids and xanthophylls, respectively. Moreover, the transgenic algae could accumulate 34% more astaxanthin than wild type. These results indicate that foreign bkt and bch genes were successfully translated into β-carotene ketolase and β-carotene hydroxylase, which were responsible for catalyzing the biosynthesis of astaxanthin in transgenic algae.展开更多
基金sponsored by the National Natural Science Foundation of China(39730340)
文摘α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein, zeaxanthin and β-cryptoxanthin. β-carotene content was relatively low and extremely low was the amount of α-carotene. Among the 53 cultivars tested, lycopene was detected only in pulp of Cara Cara navel orange. Carotenoid content in both peel and pulp of citrus fruit was the highest in Citrus reticulata Blanco and lowest in Citrus grandis Osbeck. Consequently, as far as the health protection value is considered, fruit of Citrus reticulata Blanco ranks probably higher than other citrus fruits. In fruit of most Citrus reticulata varities, β-cryptoxanthin was the main carotenoid component in pulp and its amount approximated that of lutein in peel. Content of lutein, zeaxanthin and β-cryptoxanthin in peel was about 2.515 times that in pulp on the basis of fresh weight. Thus peel was inferred to be the principal location for the carotenoid stock in citrus fruit.
基金supported by the National Natural Science Foundation of China(41176106,31470389,31470431)Shenzhen Grant Plan for Science & Technology(CXB201104210005A,JCYJ20120613112512654,JSGG20130411160539208)Guangdong Enterprise Academician Workstation(2011A090700015)
文摘β-carotene ketolase and β-carotene hydroxylase encoded by bkt and bch, respectively, are key enzymes required for astaxanthin biosynthesis in Haematococcu pluvialis 34-1n. Two expression vectors containing cDNA sequences of bkt and bch were constructed and co-transformed into cell-wall-deficient Chlamydomonas reinhardtii CC-849. Transgenic algae were screened on TAP agar plates containing 10 gg mL 1 Zeomycin. PCR-Southern analysis showed that bkt and bch were integrated into the genomes of C. reinhardtii. Transcripts of bkt and bch were further confirmed by RT-PCR-Southern analysis. Compared with the wild type, transgenic algae produced 29.04% and 30.27% more carotenoids and xanthophylls, respectively. Moreover, the transgenic algae could accumulate 34% more astaxanthin than wild type. These results indicate that foreign bkt and bch genes were successfully translated into β-carotene ketolase and β-carotene hydroxylase, which were responsible for catalyzing the biosynthesis of astaxanthin in transgenic algae.
