Biosynthesis carotenoids

Bleaching Herbicides. Membrane-based modes of herbicidal action relevant to photosynthesis (37) include those of inhibitors of carotenoid biosynthesis, eg, norflura2on, diftmon, y -phenoxyben2amines inhibitors of chlorophyll biosynthesis, eg, oxadia2on, DTP or... 

In nature, vitamin A aldehyde is produced by the oxidative cleavage of P-carotene by 15,15 - P-carotene dioxygenase. Alternatively, retinal is produced by oxidative cleavage of P-carotene to P-apo-S -carotenal followed by cleavage at the 15,15 -double bond to vitamin A aldehyde (47). Carotenoid biosynthesis and fermentation have been extensively studied both ia academic as well as ia iadustrial laboratories. On the commercial side, the focus of these iavestigations has been to iacrease fermentation titers by both classical and recombinant means. 

Although carotenogenesis in plants takes place in plastids, all of the carotenoid biosynthesis genes are nuclear encoded and their polypeptide products are imported into the plastids. Therefore, they contain a N-terminal transit peptide sequence. For example, the size of the transit peptide of PSY from ripe tomato fruit is approximately 9 kDa, corresponding to about 80 amino acid residues (Misawa et al, 1994). 

Clearly, the control of gene expression at the transcriptional level is a key regulatory mechanism controlling carotenogenesis in vivo. However, post-transcriptional regulation of carotenoid biosynthesis enzymes has been found in chromoplasts of the daffodil. The enzymes phytoene synthase (PSY) and phytoene desaturase (PDS) are inactive in the soluble fraction of the plastid, but are active when membrane-bound (Al-Babili et al, 1996 Schledz et al, 1996). The presence of inactive proteins indicates that a post-translational regulation mechanism is present and is linked to the redox state of the membrane-bound electron acceptors. In addition, substrate specificity of the P- and e-lycopene cyclases may control the proportions of the p, P and P, e carotenoids in plants (Cunningham et al, 1996). 

The carotenoid pathway may also be regulated by feedback inhibition from the end products. Inhibition of lycopene cyclisation in leaves of tomato causes increase in the expression of Pds and Psy-1 (Giuliano et al, 1993 Corona et al, 1996). This hypothesis is supported by other studies using carotenoid biosynthesis inhibitors where treated photosynthetic tissues accumulated higher concentrations of carotenoids than untreated tissues (reviewed by Bramley, 1993). The mechanism of this regulation is unknown. A contrary view, however, comes from studies on the phytoene-accumulating immutans mutant of Arabidopsis, where there is no feedback inhibition of phytoene desaturase gene expression (Wetzel and Rodermel, 1998). 

BIRD C R, RAY J A, FLETCHER J D, BONIWELL J M, BIRD A S, TEULIERES C, BLAIN I, BRAMLEY P M and SCHUCH w (1991) Using antisense RNA to study gene function inhibition of carotenoid biosynthesis in transgenic tomatoes , BioTechnology, 9, 635-9. 

BOUVIER F, d harlingue A, BACKHAUs R A, KUMAGAi H and CAMARA B (2000) Identification of neoxanthin synthase as a carotenoid cyclase pmalog , FEBSLetters, 267, 6346-52. BRAMLEY P M (1993) Inhibition of carotenoid biosynthesis , in Yoimg A J and Britton G, Carotenoids in Photosynthesis, London, Chapman and HaU, 127-59. 

BRAMLEY p M (1997) The regulation and genetic manipulation of carotenoid biosynthesis in tomato fruit , PureAppl Chem, 69, 2159-62. 

GiuLiANO G (1996) Regulation of a carotenoid biosynthesis gene promoter during plant development , Plant J, 9, 505-12. 

CUNNINGHAM F X Jr and GANTT E (1998) Genes and enzymes of carotenoid biosynthesis in plants , Ann Rev Plant Physiol Plant Mol Biol, 49, 557-83. 

FRASER P D, TRUESDALE M R, BIRD C R, SCHUCH W and BRAMLEY P M (1994) CarOtenoid biosynthesis during tomato fruit development . Plant Physiol, 105, 405-13. 

GiuLiANO G, BARTLEY G E and scoLNiK p A (1993) Regulation of carotenoid biosynthesis during tomato fruit development . Plant Cell, 5, 379-87. 

HARKER M and HIRSCHBERG J (1998) Molecular biology of carotenoid biosynthesis in photo synthetic organisms . Methods Enzymol, 297, 244-63. 

HIRSCHBERG J (2001) Carotenoid biosynthesis in flowering plants , Curr Opin Plant Biol, 4, 210-18. 

PARK H, KREUNEN s s, cuTTRiss A J, DELLAPENNA D and POGSON B (2002) Identification of the carotenoid isomerase provides insight into carotenoid biosynthesis, prolamellar body formation and photomorphogenesis . Plant Cell, 14, 321-32. 

RONEN G, COHEN M, ZAMIR D and HIRSCHBERG J (1999) Regnlation of carotenoid biosynthesis during tomato fruit development expression of the gene for lycopene epsilon cyclase is down regulated during ripening and is elevated in the mutant delta . Plant J, 17, 341-51. 

SANDMANN G (2002) Molecular evolution of carotenoid biosynthesis from bacteria to plants . Physiol Plantarum, 116, 431-40. 

TRUESDALE M R (1994) Carotenoid biosynthesis in the tomato, PhD thesis. University of London. 

Carotenoid Biosynthesis Examples of Biotechnology FOR Food Coeorants... 

We have chosen carotenoid biosynthesis as the example system for demonstrating the prospects of biotechnology of food colorants for several reasons. Carotenoid biosynthesis is the second most understood system. Multiple examples of valuable food colorant engineering in fungi, bacteria, and plants have been reported. Finally, carotenogenesis in cereal crops such as maize and rice is the primary focus of our research efforts. Hopefully, we provide the food technologist with a template with which to examine other industrially important pigment systems. 

Desaturation and Isomerization to Coeored Carotenoids Biosynthesis of Lycopene... 

Unicelluar algal and bacterial genes were the first to be isolated and characterized and led to the isolation of most of the higher plant genes involved in carotenoid biosynthesis. Carotenogenic gene clusters from bacteria and algae" - - - contributed immensely to the elucidation of the carotenoid pathway. 

Careful empirical selection of the expression platform for carotenogenesis has included selection of the best strains for stability and degree of accumulation and the selection of compatible drug-resistance combinations and low copy number polycistronic plasmids to enhance product accumulation by decrease of metabolic burden." 5 Matthews and Wurtzel discussed culture and induction conditions - that have been explored in most studies. Most efforts to engineer carotenoid biosynthesis in E. coli focused on the genes and enzymes of the pathway and had a modest effect on improved accumulation. For example, substitution and over-expression of a GGPPS that uses IPP directly (discussed in... 

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