RESUMO
Ischemia-reperfusion (IR) is a deleterious condition associated with liver transplantation or resection that involves pro-oxidant and pro-inflammatory mechanisms. Considering that Rosa Mosqueta (RM) oil composition is rich in protective components such as α-linolenic acid (ALA) and tocopherols, we studied the effects of RM oil supplementation given prior to an IR protocol. Male Sprague-Dawley rats receiving RM oil (0.4 mL d-1) for 21 days were subjected to 1 h of ischemia followed by 20 h reperfusion. Parameters of liver injury (serum transaminases, histology), oxidative stress [liver contents of protein carbonyls, thiobarbituric acid reactants, Nrf2 activity and its target mRNA expression of heme oxygenase-1 (HO-1) and NADPH-quinone oxidoreductase-1 (NQO-1)] and inflammation [nuclear factor-κB (NF-κB) and its target mRNA expression of tumor necrosis factor-α (TNF-α) and interleukine-1ß (IL-1ß)] were studied. RM oil increased liver ALA and its derived EPA and DHA fatty acids' contents, with enhancement in those of α- and γ-tocopherols. IR induced inflammatory liver injury, with enhancement in serum transaminases, oxidative stress-related parameters with reduced Nrf2 signaling, and higher pro-inflammatory cytokines, indexes that were attenuated or abrogated by RM oil pretreatment. It is concluded that RM oil supplementation represents a novel non-invasive preconditioning strategy against liver injury induced by IR that has potential clinical applications in metabolic stress conditions.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Antioxidantes/uso terapêutico , Suplementos Nutricionais , Fígado/metabolismo , Óleos Voláteis/uso terapêutico , Traumatismo por Reperfusão/prevenção & controle , Rosa/química , Animais , Ácidos Docosa-Hexaenoicos/metabolismo , Ácido Eicosapentaenoico/metabolismo , Regulação da Expressão Gênica , Fígado/irrigação sanguínea , Fígado/imunologia , Fígado/patologia , Masculino , Fator 2 Relacionado a NF-E2/antagonistas & inibidores , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo , Distribuição Aleatória , Ratos Sprague-Dawley , Traumatismo por Reperfusão/imunologia , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Sementes/química , Transdução de Sinais , Desmame , Ácido alfa-Linolênico/metabolismo , Ácido alfa-Linolênico/uso terapêutico , alfa-Tocoferol/metabolismo , alfa-Tocoferol/uso terapêutico , gama-Tocoferol/metabolismo , gama-Tocoferol/uso terapêuticoRESUMO
The purpose of this study was to characterize olive core collection with amplified fragment length polymorphism (AFLP) markers and fruit traits and to determine AFLP markers significantly associated with these fruit characters in olive. A total of 168 polymorphic AFLP markers generated by five primer combinations and nine fruit traits were used to characterize relationships between 18 olive cultivars. Although all olive cultivars were discriminated from each other by either AFLP markers (<0.75 similarity level) or fruit traits, clustering based on the AFLP markers and fruit traits was not significantly correlated (r = 0.13). Partial clustering of olive cultivars by AFLP markers according to their geographical origin was observed. Associations of AFLP markers with fruits were determined using a multiple-regression analysis with stepwise addition of AFLP markers. Significant associations between eight AFLP markers and fruit traits were identified. While five AFLP markers demonstrated significant negative correlation with fruit and stone weight, width and length and total polyphenols (P < 0.05), three AFLP markers displayed significant positive correlation with α-tocopherol and γ-tocopherol (P < 0.01). This is the first report on the association of molecular markers with fruit traits in olive. Molecular markers associated with morphological and agronomic traits could be utilized for the breeding of olive cultivars. However, the association power of these markers needs to be confirmed in larger populations, and highly correlated markers should then be converted to PCR-based DNA markers such as sequence-characterized amplified region markers for better utilization.
Assuntos
Análise do Polimorfismo de Comprimento de Fragmentos Amplificados/métodos , Frutas/genética , Marcadores Genéticos/genética , Olea/genética , Análise por Conglomerados , DNA de Plantas/genética , Frutas/metabolismo , Olea/classificação , Olea/metabolismo , Polimorfismo Genético , Análise de Regressão , alfa-Tocoferol/metabolismo , gama-Tocoferol/metabolismoRESUMO
γ-tocopherol methyltransferase is an important rate-limiting enzyme involved in tocopherol biosynthesis. The full-length cDNA encoding γ-tocopherol methyltransferase (designated as LsTMT) was cloned from Lactuca sativa for the first time by rapid amplification of cDNA ends and characterized by means of quantitative RT-PCR. The full-length cDNA of LsTMT was 1131 bp, with an open reading frame of 897 bp encoding a γ-tocopherol methyltransferase protein of 298 amino acids, with a calculated molecular mass of 33.06 kDa and an isoelectric point of 5.86. Comparative analysis revealed that LsTMT has a close similarity with γ-TMTs from other plant species. Bioinformatic analysis indicated that LsTMT shares a common evolutionary origin based on sequence similarity and has the closest relationship to γ-TMT from the sunflower, Helianthus annuus. Based on quantitative RT-PCR analysis, we found that expression of LsTMT is induced and strengthened by oxidative stresses such as strong light and drought. The cloning and characterization of LsTMT will be helpful to further understanding its role in the tocopherol biosynthesis pathway. We consider it to be a candidate gene for metabolic engineering of vitamin E in vegetable crops.
Assuntos
Lactuca/genética , Metiltransferases/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Biologia Computacional , DNA Complementar/biossíntese , DNA Complementar/genética , Secas , Regulação da Expressão Gênica de Plantas , Helianthus/genética , Lactuca/enzimologia , Luz , Metiltransferases/química , Metiltransferases/metabolismo , Dados de Sequência Molecular , Técnicas de Amplificação de Ácido Nucleico , Fases de Leitura Aberta , Filogenia , Proteínas de Plantas/metabolismo , Homologia de Sequência de Aminoácidos , gama-Tocoferol/metabolismoRESUMO
The 2-C-methyl-D-erythritol-4-phosphate and shikimate pathways were found to be active in Plasmodium falciparum and both can result in vitamin E biosynthesis in plants and algae. This study biochemically confirmed vitamin E biosynthesis in the malaria parasite, which can be inhibited by usnic acid. Furthermore, we found evidence pointing to a role of this vitamin in infected erythrocytes. These findings not only contribute to current understanding of P. falciparum biology but also reveal a pathway that could serve as a chemotherapeutic target.
Assuntos
Eritrócitos/parasitologia , Estágios do Ciclo de Vida , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/metabolismo , Vitamina E/biossíntese , Animais , Benzofuranos/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Estágios do Ciclo de Vida/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/fisiologia , Esquizontes/efeitos dos fármacos , Esquizontes/metabolismo , Vitamina E/análise , alfa-Tocoferol/análise , alfa-Tocoferol/metabolismo , gama-Tocoferol/análise , gama-Tocoferol/metabolismoRESUMO
Previous reports proposed that peroxynitrite (ONOO-) oxidizes alpha-tocopherol (alpha-TOH) through a two-electron concerted mechanism. In contrast, ONOO- oxidizes phenols via free radicals arising from peroxo bond homolysis. To understand the kinetics and mechanism of alpha-TOH and gamma-tocopherol (gamma-TOH) oxidation in low-density lipoprotein (LDL) (direct vs. radical), we exposed LDL to ONOO- added as a bolus or an infusion. Nitric oxide (.NO), ascorbate and CO2 were used as key biologically relevant modulators of ONOO- reactivity. Although approximately 80% alpha-TOH and gamma-TOH depletion occurred within 5 min of incubation of 0.8 microM LDL with a 60 microM bolus of ONOO-, an equimolar infusion of ONOO- over 60 min caused total consumption of both antioxidants. gamma-Tocopherol was preserved relative to alpha-TOH, probably due to gamma-tocopheroxyl radical recycling by alpha-TOH. alpha-TOH oxidation in LDL was first order in ONOO- with approximately 12% of ONOO- maximally available. Physiological concentrations of.NO and ascorbate spared both alpha-TOH and gamma-TOH through independent and additive mechanisms. High concentrations of.NO and ascorbate abolished alpha-TOH and gamma-TOH oxidation. Nitric oxide protection was more efficient for alpha-TOH in LDL than for ascorbate in solution, evidencing the kinetically highly favored reaction of lipid peroxyl radicals with.NO than with alpha-TOH as assessed by computer-assisted simulations. In addition, CO2 (1.2 mM) inhibited both alpha-TOH and lipid oxidation. These results demonstrate that ONOO- induces alpha-TOH oxidation in LDL through a one-electron free radical mechanism; thus the inhibitory actions of.NO and ascorbate may determine low alpha-tocopheryl quinone accumulation in tissues despite increased ONOO- generation.
Assuntos
Peroxidação de Lipídeos/efeitos dos fármacos , Lipoproteínas LDL/metabolismo , Ácido Peroxinitroso/farmacologia , alfa-Tocoferol/metabolismo , gama-Tocoferol/metabolismo , Ácido Ascórbico/farmacologia , Dióxido de Carbono/farmacologia , Humanos , Cinética , Óxido Nítrico/farmacologia , Oxirredução/efeitos dos fármacos , Ácido Peroxinitroso/administração & dosagem , Ácido Peroxinitroso/antagonistas & inibidoresRESUMO
We have studied the role of three Mn(III)porphyrins differing in charge, alkyl substituent length and reactivity, on LDL exposed to low fluxes of peroxynitrite (PN) in the presence of uric acid. Mn(III)porphyrins (5 microM, MnTE-2-PyP(5+), MnTnOct-2-PyP(5+), and MnTCPP(3-)) plus uric acid (300 microM) inhibited cholesteryl ester hydroperoxide formation, changes in REM as well as spared alpha- and gamma-tocopherol. MnTnOct-2-PyP(5+), the more lipophilic compound, was the most effective in protecting LDL lipids, while MnTCPP(3-) exerted the lesser protection. Mn(III)porphyrins react fast with PN ( approximately 10(5)-10(7) M(-1) s(-1)) to yield a O=Mn(IV) complex. The stoichiometry of uric acid consumption was approximately 1.7 moles per mol of PN, in agreement with reactions with both the O=Mn(IV) complex and nitrogen dioxide. A shift from an anti- to a pro-oxidant action of the Mn(III)porphyrin was observed after uric acid was significantly consumed, supporting competition reactions between LDL targets and uric acid for the O=Mn(IV) complex. Overall, the data is consistent with the catalytic reduction of PN in a cycle that involves a one electron oxidation of Mn(III) to Mn(IV) by PN followed by the reduction back to Mn(III) by uric acid. These antioxidant effects should predominate under in vivo conditions having plasma uric acid concentration range between 150 and 500 microM.