PubMed · 6234142
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R Valsecchi, T Cainelli. 1984. Chromium dermatitis and ascorbic acid.. https://doi.org/10.1111/j.1600-0536.1984.tb00115.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Ascorbic acid (AsA) is an essential nutritional component and powerful antioxidant in vegetables, and in plants, AsA levels are regulated by light. AsA levels in the leaves of Chinese chive (Allium tuberosum Rottler ex Spr), a popular vegetable, are poorly understood. Thus, this study was performed to assess the influence of light on AsA biosynthesis in chive and select related genes (AtuGGP1 and AtuGME1); in addition, bioinformatic analyses and gene expression level assays were performed. The biological information obtained for AtuGGP1 and AtuGME1 was analysed with several tools, including NCBI, DNAMAN, and MEGA11. After different light treatments were performed, the Chive AsA content and AtuGGP1 and AtuGME1 expression levels were determined. These results suggest that 1) compared with natural light, continuous darkness inhibited AsA synthesis in chives. 2) The amino acid sequences of AtuGGP1 and AtuGME1 are very similar to those of other plants. 3) The trends observed for the expression levels of AtuGGP1 and AtuGME1 were consistent with the AsA content observed in chives. Hence, we speculated that light controls AsA biosynthesis in chives by regulating AtuGGP1 and AtuGME1 expression. This study provided impactful and informative evidence regarding the functions of GGP and GME in chives.
Diazobenzene sulfonic acid (DABS) has been used to label thiols and amino groups on cell-surface proteins. However, we found that in addition to inhibiting an ascorbate-dependent trans-plasma membrane oxidoreductase in human erythrocytes, it also depleted alpha-tocopherol severely in the cell membrane. When erythrocytes were loaded with ascorbate, DABS-dependent loss of alpha-tocopherol was decreased, despite little change in intracellular ascorbate content. Sparing of alpha-tocopherol also was seen in erythrocyte ghosts resealed to contain ascorbate, although this was accompanied by loss of intravesicular ascorbate, probably due to the inability of ghosts to recycle ascorbate. A transmembrane transfer of electrons from ascorbate was confirmed by electron paramagnetic resonance spectroscopy, in which extracellular DABS was found to generate the ascorbate free radical within cells. When the membrane content of alpha-tocopherol was decreased to 20% of the initial value by DABS treatment, lipid peroxidation ensued, manifest by generation of F(2)-isoprostanes in the cell membranes. Intracellular ascorbate also strongly protected against F(2)-isoprostane formation. These results show that DABS causes an oxidant stress at the membrane surface that is transmitted within the cell, in part by an alpha-tocopherol-dependent mechanism, and that ascorbate recycling of alpha-tocopherol can protect against loss of alpha-tocopherol and the ensuing lipid peroxidation.
Saccharomyces cerevisiae cells incubated with D-glucose (D-Glc), D-galactose or D-mannose (D-Man) synthesised D-erythroascorbic acid (D-EAA) but not L-ascorbic acid (L-AA). Accumulation of D-EAA was observed in cells incubated with D-arabinose (D-Ara) whilst accumulation of L-AA occurred in cells incubated with L-galactose (L-Gal), L-galactono-1,4-lactone and L-gulono-1,4-lactone. When S. cerevisiae cells were incubated with D-[U-(14)C]Glc, D-[U-(14)C]Man or L-[1-(14)C]Gal, incorporation of radioactivity into L-AA was observed only with L-[1-(14)C]Gal. Pre-incubation of yeast cells with D-Ara substantially reduced the incorporation of L-[1-(14)C]Gal into L-AA. Our results indicate that, under appropriate conditions, yeast cells can synthesise L-AA via the pathway naturally used for D-EAA biosynthesis.