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The carotenogenesis pathway via the isoprenoid-beta-carotene interference approach in a new strain of Dunaliella salina isolated from Baja California Mexico.

Paniagua-Michel J, Capa-Robles W, Olmos-Soto J, Gutierrez-Millan LE - Mar Drugs (2009)

Bottom Line: When Carotenogenic and non-carotenogenic cells of D. salina BC02 were grown under photoautotrophic growth conditions in the presence of 200 microM fosmidomycin, carotenogenesis and the synthesis of beta-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.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Biotechnology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada 22860, México. jpaniagu@cicese.mx

ABSTRACT
D. salina is one of the recognized natural sources to produce beta-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 beta-carotene. In this study, Dunaliella salina (BC02) isolated from La Salina BC Mexico, was subjected to the method of isoprenoids-beta-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 microM fosmidomycin, carotenogenesis and the synthesis of beta-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 beta-carotene levels very similar to those of control cell cultures indicating that mevinolin not pursued any indirect action in the biosynthesis of isoprenoids and had no effect at the level of the HMG-CoA reductase, the key enzyme of the Ac/MVA pathway.

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Culture flasks containing D. salina cells cultured under carotenogenic conditions and exposed to mevinolin (uninterrupted synthesis of β-carotene, left)  and to fosmidomycin (blocked synthesis of β-carotene, right) respectively.
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f4-marinedrugs-07-00045: Culture flasks containing D. salina cells cultured under carotenogenic conditions and exposed to mevinolin (uninterrupted synthesis of β-carotene, left) and to fosmidomycin (blocked synthesis of β-carotene, right) respectively.

Mentions: Mevinolin treated D. salina cells continue to grow and synthesizing carotenoids, as observed in figure 4, cells turned orange-yellow and a decrease in cell density was observed and the β-carotene levels were similar to those of control cell cultures. Figure 4 shows green cells as indicative of photosynthetic growth and blocked synthesis of carotenoids and β-carotene in D. salina by fosmidomycin. The fact that the treatment with fosmidomycin did not completely suppress the system of renewal of its pools of isoprenoids and respective products from carotenogenesis in Dunaliella salina, viz, β-carotene indicates the effective inhibition of the essential regulatory step, DOXP reductoisomerase (generated under photosynthetic conditions) of the DOXP/MEP pathway by fomidomycin which is a structural analogue to 2-C-methylerythrose 4-phosphate, the intermediate in the enzymic reaction of DXR [20]. The results evidenced the absence of HMGR, as well as a suppression of the C5-units of biosynthesis, resulting in a shortage of the bulk isoprenoids like carotenoids, β-carotene, and chlorophylls (by phytol reduction, side chain of chlorophylls) at the level of chloroplast, the exclusive site of carotenogenesis in D. salina.


The carotenogenesis pathway via the isoprenoid-beta-carotene interference approach in a new strain of Dunaliella salina isolated from Baja California Mexico.

Paniagua-Michel J, Capa-Robles W, Olmos-Soto J, Gutierrez-Millan LE - Mar Drugs (2009)

Culture flasks containing D. salina cells cultured under carotenogenic conditions and exposed to mevinolin (uninterrupted synthesis of β-carotene, left)  and to fosmidomycin (blocked synthesis of β-carotene, right) respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2666888&req=5

f4-marinedrugs-07-00045: Culture flasks containing D. salina cells cultured under carotenogenic conditions and exposed to mevinolin (uninterrupted synthesis of β-carotene, left) and to fosmidomycin (blocked synthesis of β-carotene, right) respectively.
Mentions: Mevinolin treated D. salina cells continue to grow and synthesizing carotenoids, as observed in figure 4, cells turned orange-yellow and a decrease in cell density was observed and the β-carotene levels were similar to those of control cell cultures. Figure 4 shows green cells as indicative of photosynthetic growth and blocked synthesis of carotenoids and β-carotene in D. salina by fosmidomycin. The fact that the treatment with fosmidomycin did not completely suppress the system of renewal of its pools of isoprenoids and respective products from carotenogenesis in Dunaliella salina, viz, β-carotene indicates the effective inhibition of the essential regulatory step, DOXP reductoisomerase (generated under photosynthetic conditions) of the DOXP/MEP pathway by fomidomycin which is a structural analogue to 2-C-methylerythrose 4-phosphate, the intermediate in the enzymic reaction of DXR [20]. The results evidenced the absence of HMGR, as well as a suppression of the C5-units of biosynthesis, resulting in a shortage of the bulk isoprenoids like carotenoids, β-carotene, and chlorophylls (by phytol reduction, side chain of chlorophylls) at the level of chloroplast, the exclusive site of carotenogenesis in D. salina.

Bottom Line: When Carotenogenic and non-carotenogenic cells of D. salina BC02 were grown under photoautotrophic growth conditions in the presence of 200 microM fosmidomycin, carotenogenesis and the synthesis of beta-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.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Biotechnology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada 22860, México. jpaniagu@cicese.mx

ABSTRACT
D. salina is one of the recognized natural sources to produce beta-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 beta-carotene. In this study, Dunaliella salina (BC02) isolated from La Salina BC Mexico, was subjected to the method of isoprenoids-beta-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 microM fosmidomycin, carotenogenesis and the synthesis of beta-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 beta-carotene levels very similar to those of control cell cultures indicating that mevinolin not pursued any indirect action in the biosynthesis of isoprenoids and had no effect at the level of the HMG-CoA reductase, the key enzyme of the Ac/MVA pathway.

Show MeSH
Related in: MedlinePlus