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Chemical oxidation of citronellol in the ‘dark’ and ‘light’ conditions
Abstracts / Chemistry and Physics of Lipids 164S (2011) S38–S41
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Chemical oxidation of citronellol in the ‘dark’ and ‘light’ conditions
Two different oxidative stressors cause distinct effects on accumulation of polyisoprenoid alcohols in Arabidopsis thaliana hairy roots
Joanna Siedlecka 1,∗ , Iwona Lozinska 2 , Anna Zawadzka 2 , Zbigniew Czarnocki 2 , Ewa Kaczorowska 3 , Magdalena Kania 4 , Witold Danikiewicz 4 , Ewa Swiezewska 1 1
Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland 2 Department of Chemistry, Warsaw University, Warsaw, Poland 3 Laboratory of Biological NMR, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland 4 Laboratory of Mass Spectrometry, Institute of Organic Chemistry PAS, Warsaw, Poland
Polyisoprenoid alcohols are synthesized in all eukaryotic cells as a mixture of homologues. Their molecules consist of several up to more than 100 isoprene residues linked head-to-tail. The hydroxyl group is located at the -end and a hydrogen atom at the ␣-end. The saturated isoprene alcohols called dolichols, occur mainly in yeast, animal cells, plant roots and mushrooms. The polyprenols, unsaturated terpenoids, are mainly found in bacteria and plant photosynthetic tissues, wood, seeds and flowers. Molecules of these lipids, with numerous double bonds, are a perfect target for oxidation. In plants reactive oxygen species (ROS) are produced continuously, especially in mitochondria, chloroplasts and peroxisomes. The increase of dolichols and polyprenols during the life span of organisms occurs concomitantly with a high-increase of free radicals. Living organisms had to develop a complex array for the control of production and removal of oxygen species. Putative protection of cellular membranes against peroxidation has been recently postulated as a new function of dolichol. Polyisoprenoid chain might constitute a shield against reactive oxygen species, generated either by UV light or by chemicals. Singlet oxygen can be chemically generated in a great variety of ways. In this study two different types of oxidation reactions of -citronellol (a short chain dolichol) with singlet oxygen, a representative of ROS, were performed. The first reaction was carried out at −78 ◦ C, in the ‘light conditions’, while the oxygen was excited to the singlet state by halogen lamp irradiation. The porphyrin was used as a photosensitizer. The products of reaction were chromatographically separated and analyzed by HPLC/ESI-MS, 1 H and 13 C NMR spectroscopy. Three main products were identified. In the MS spectrum of purified products, the sodium ions in the positive ion mode of expected products were observed (1,6-diol, 1,7-diol and epoksydiol of citronellol). The second oxidation reaction of -citronellol was performed in the ‘dark conditions’ using hydrogen peroxide and sodium molybdate as a catalyst. The profile of products seemed to be very similar to that obtained during photooxidation (TLC). These experiments confirmed that isoprenoid alcohols are prone to the oxidation with singlet oxygen. doi:10.1016/j.chemphyslip.2011.05.120
Adam Jozwiak ∗ , Ewa Swiezewska Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland Plants have evolved a wide range of mechanisms to cope with biotic and abiotic stresses. Upon adverse conditions, complex metabolic changes occur involving the primary metabolism and mobilization of so called ‘secondary metabolites’, e.g. terpenoids. Recently, the involvement of polyisoprenoid alcohols in plant resistance response to stress has been suggested. In this study in vitro root culture of Arabidopsis thaliana was applied as a model. Dolichol content was analyzed using HPLC/UV. Roots of Arabidopsis accumulated three-family mixture of dolichols consisting of short, medium and long alcohols, with Dol-13, Dol-16 and Dol-21 dominating, respectively. Effect of the two stressors (methyl viologen and hydrogen peroxide) on dolichol accumulation has been analyzed. Presence of H2 O2 (1 mM) in the culture medium resulted in the statistically significant increase of dolichol accumulation. Surprisingly, addition of paraquat in culture medium (1 M) cause decreased accumulation of polyisoprenoid alcohols. To evaluate level of lipid peroxidation, concentration of malondialdehyde was analyzed spectrophotometrically. Both, hydrogen peroxide and methyl viologen caused higher concentration of peroxidated lipids in root tissue. In both cases malondialdehyde level was increased more than two-fold in comparison to the control. Changed concentration of dolichol in Arabidopsis roots treated with hydrogen peroxide supports the fact that hydrogen peroxide acts as signaling molecule in response to different biotic and abiotic stresses. What is more, we have also observed increased dolichol accumulation in Arabidopsis roots upon cadmium and osmotic stress. Methyl viologen disrupts the flow of electrons in mitochondrial oxidative chain leading to increased accumulation of superoxide radical, which destroy lipids in the cell but does not act as signaling molecule. To further investigate this phenomenon experiments on the effect of the H2 O2 and MV on the expression of cis-prenyltransferases (the enzymes responsible for elongation of the polyisoprenoid chain) are currently performed. doi:10.1016/j.chemphyslip.2011.05.121 P 51 Expression and characterization of two isoformes of cisprenyltransferase AtCPT6 and AtCPT7 in Arabidopsis thaliana Liliana Surmacz ∗ , Ewa Swiezewska Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland Polyisoprenoid alcohols (dolichols and polyprenols) are widespread in nature from bacteria to mammalian cells. They modulate the properties of the biological membranes, participate in glycosyl-phosphoinosytol membrane (GPI) anchor, protein C- and O-mannosylation, and protein N- and O-glycosylation. Polyisoprenoids are formed via condensations of isopentenyl diphosphates (IPP) molecules with farnesyl diphosphate (FPP) performed by cis-prenyltransferase (CPT). Several genes encoding CPT have been cloned from bacteria, plants and mammals. Interestingly, Arabidopsis thaliana ten puta-
S39
P 49
P 50
Chemical oxidation of citronellol in the ‘dark’ and ‘light’ conditions
Two different oxidative stressors cause distinct effects on accumulation of polyisoprenoid alcohols in Arabidopsis thaliana hairy roots
Joanna Siedlecka 1,∗ , Iwona Lozinska 2 , Anna Zawadzka 2 , Zbigniew Czarnocki 2 , Ewa Kaczorowska 3 , Magdalena Kania 4 , Witold Danikiewicz 4 , Ewa Swiezewska 1 1
Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland 2 Department of Chemistry, Warsaw University, Warsaw, Poland 3 Laboratory of Biological NMR, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland 4 Laboratory of Mass Spectrometry, Institute of Organic Chemistry PAS, Warsaw, Poland
Polyisoprenoid alcohols are synthesized in all eukaryotic cells as a mixture of homologues. Their molecules consist of several up to more than 100 isoprene residues linked head-to-tail. The hydroxyl group is located at the -end and a hydrogen atom at the ␣-end. The saturated isoprene alcohols called dolichols, occur mainly in yeast, animal cells, plant roots and mushrooms. The polyprenols, unsaturated terpenoids, are mainly found in bacteria and plant photosynthetic tissues, wood, seeds and flowers. Molecules of these lipids, with numerous double bonds, are a perfect target for oxidation. In plants reactive oxygen species (ROS) are produced continuously, especially in mitochondria, chloroplasts and peroxisomes. The increase of dolichols and polyprenols during the life span of organisms occurs concomitantly with a high-increase of free radicals. Living organisms had to develop a complex array for the control of production and removal of oxygen species. Putative protection of cellular membranes against peroxidation has been recently postulated as a new function of dolichol. Polyisoprenoid chain might constitute a shield against reactive oxygen species, generated either by UV light or by chemicals. Singlet oxygen can be chemically generated in a great variety of ways. In this study two different types of oxidation reactions of -citronellol (a short chain dolichol) with singlet oxygen, a representative of ROS, were performed. The first reaction was carried out at −78 ◦ C, in the ‘light conditions’, while the oxygen was excited to the singlet state by halogen lamp irradiation. The porphyrin was used as a photosensitizer. The products of reaction were chromatographically separated and analyzed by HPLC/ESI-MS, 1 H and 13 C NMR spectroscopy. Three main products were identified. In the MS spectrum of purified products, the sodium ions in the positive ion mode of expected products were observed (1,6-diol, 1,7-diol and epoksydiol of citronellol). The second oxidation reaction of -citronellol was performed in the ‘dark conditions’ using hydrogen peroxide and sodium molybdate as a catalyst. The profile of products seemed to be very similar to that obtained during photooxidation (TLC). These experiments confirmed that isoprenoid alcohols are prone to the oxidation with singlet oxygen. doi:10.1016/j.chemphyslip.2011.05.120
Adam Jozwiak ∗ , Ewa Swiezewska Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland Plants have evolved a wide range of mechanisms to cope with biotic and abiotic stresses. Upon adverse conditions, complex metabolic changes occur involving the primary metabolism and mobilization of so called ‘secondary metabolites’, e.g. terpenoids. Recently, the involvement of polyisoprenoid alcohols in plant resistance response to stress has been suggested. In this study in vitro root culture of Arabidopsis thaliana was applied as a model. Dolichol content was analyzed using HPLC/UV. Roots of Arabidopsis accumulated three-family mixture of dolichols consisting of short, medium and long alcohols, with Dol-13, Dol-16 and Dol-21 dominating, respectively. Effect of the two stressors (methyl viologen and hydrogen peroxide) on dolichol accumulation has been analyzed. Presence of H2 O2 (1 mM) in the culture medium resulted in the statistically significant increase of dolichol accumulation. Surprisingly, addition of paraquat in culture medium (1 M) cause decreased accumulation of polyisoprenoid alcohols. To evaluate level of lipid peroxidation, concentration of malondialdehyde was analyzed spectrophotometrically. Both, hydrogen peroxide and methyl viologen caused higher concentration of peroxidated lipids in root tissue. In both cases malondialdehyde level was increased more than two-fold in comparison to the control. Changed concentration of dolichol in Arabidopsis roots treated with hydrogen peroxide supports the fact that hydrogen peroxide acts as signaling molecule in response to different biotic and abiotic stresses. What is more, we have also observed increased dolichol accumulation in Arabidopsis roots upon cadmium and osmotic stress. Methyl viologen disrupts the flow of electrons in mitochondrial oxidative chain leading to increased accumulation of superoxide radical, which destroy lipids in the cell but does not act as signaling molecule. To further investigate this phenomenon experiments on the effect of the H2 O2 and MV on the expression of cis-prenyltransferases (the enzymes responsible for elongation of the polyisoprenoid chain) are currently performed. doi:10.1016/j.chemphyslip.2011.05.121 P 51 Expression and characterization of two isoformes of cisprenyltransferase AtCPT6 and AtCPT7 in Arabidopsis thaliana Liliana Surmacz ∗ , Ewa Swiezewska Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics PAS, Warsaw, Poland Polyisoprenoid alcohols (dolichols and polyprenols) are widespread in nature from bacteria to mammalian cells. They modulate the properties of the biological membranes, participate in glycosyl-phosphoinosytol membrane (GPI) anchor, protein C- and O-mannosylation, and protein N- and O-glycosylation. Polyisoprenoids are formed via condensations of isopentenyl diphosphates (IPP) molecules with farnesyl diphosphate (FPP) performed by cis-prenyltransferase (CPT). Several genes encoding CPT have been cloned from bacteria, plants and mammals. Interestingly, Arabidopsis thaliana ten puta-