The Carotenogenesis Pathway via the Isoprenoid-β-carotene Interference Approach in a New Strain of Dunaliella salina Isolated from Baja California Mexico

Abstract

D. salina is one of the recognized natural sources to produce β-carotene, and an useful model for studying the role of inhibitors and enhancers of carotenogenesis. However there is little information in D. salina regarding whether the isoprenoid substrate can be influenced by stress factors (carotenogenic) or selective inhibitors which in turn may further contribute to elucidate the early steps of carotenogenesis and biosynthesis of β-carotene. In this study, Dunaliella salina (BC02) isolated from La Salina BC Mexico, was subjected to the method of isoprenoids-β-carotene interference in order to promote the interruption or accumulation of the programmed biosynthesis of carotenoids. When Carotenogenic and non-carotenogenic cells of D. salina BC02 were grown under photoautotrophic growth conditions in the presence of 200 µM fosmidomycin, carotenogenesis and the synthesis of β-carotene were interrupted after two days in cultured D. salina cells. This result is an indirect consequence of the inhibition of the synthesis of isoprenoids and activity of the recombinant DXR enzyme thereby preventing the conversion of 1-deoxy-D-xylulose 5-phosphate (DXP) to 2-C-methyl-D-erythritol (MEP) and consequently interrupts the early steps of carotenogenesis in D. salina. The effect at the level of proteins and RNA was not evident. Mevinolin treated D. salina cells exhibited carotenogenesis and β-carotene levels very similar to those of control cell cultures indicating that mevinolin not pursued any indirect action in the biosynthesis of isoprenoids OPEN ACCESS Mar. Drugs 2009, 7 46and had no effect at the level of the HMG-CoA reductase, the key enzyme of the Ac/MVA pathway.

Identification of Microalgae Producers of Commercially Important Compounds

“…The β-carotene is composed of a mixture of stereoisomers 9-cis and all-trans reaching more than 10% of dry weight in Dunaliella. These features set Dunaliella as an excellent model to elucidate the biosynthetic pathway of carotenoids and their regulation, as well as for the commercial production of carotenoids [7,8,12].…”

“…The β-carotene has been used for many years as a food coloring compound, provitamin A, additive in cosmetics, as a bioactive molecule in functional foods, antioxidant, and as a precursor to retinoic acid [7,8,12].…”

“…Furthermore, carotenoids also are used to promote the health and fertility of animals, as well as of humans. From 400 known carotenoids, very few are commercially applied; the therapeutic and nutritional importance of some carotenoids lies in their characteristics to act as a provitamin A and subsequently as retinoic acid [4,7,8].…”

“…β-carotene is the only carotenoid that has the property to form two vitamin A molecules; the other ∼50 carotenoids that also act as vitamin A precursors produce in mammals only one vitamin A molecule [4,7,8].…”

Dunaliella Identification Using DNA Fingerprinting Intron-Sizing Method and Species-Specific Oligonucleotides

“…Microalgae include a very diverse group of eukaryotic organisms that play important ecologicaleenvironmental roles and constitute a natural source of a variety of bioactive compounds and molecules for pharmaceutical, food, and cosmetic applications (Guedes, 2011;Paniagua-Michel et al, 2009). With fast growth rates and low production costs, microalgae provide useful cell factories for the production of valuable compounds and recombinant products like lipids, biofuels, vaccines, antibodies, and carotenoids (Fletcher et al, 2007;Greenwell et al, 2010;Mayfield et al, 2007;Skjanes et al, 2013;Vilchez et al, 2011).…”