Photosynthesis is a highly robust process allowing for rapid adjustment to changing environmental conditions. The efficient acclimation depends on balanced redox metabolism and control of reactive oxygen species release which triggers signaling cascades and potentially detrimental oxidation reactions. Thiol peroxidases of the peroxiredoxin and glutathione peroxidase type, and ascorbate peroxida...

Leucocyte ascorbate (LA) and serum ascorbate (SA) were measured in patients who had sustained an acute cerebrovascular accident. There was a significant fall in LA and Sa within 24 hours of the incident and this persisted for several weeks. The "stress" of the event resulted in a rise in serum cortisol concentration and depletion of both pituitary and adrenal glands of ascorbate when examined a...

Ascorbic Acid, Dehydroascorbic Acid, Redox Potential, Free Radical, ESR The previously reported interaction between ascorbate monoanion and dehydroascorbic acid yielding semidehydroascorbic acid has been shown to be thermodynamically unfeasible and non-existent. No evidence for radical for­ mation in the reinvestigation of the reaction using ESR spectroscopy under careful exclusion of air could...

A molecular proton reduction catalyst [FeFe](dcbdt)(CO)6 (1, dcbdt = 1,4-dicarboxylbenzene-2,3-dithiolate) with structural similarities to [FeFe]-hydrogenase active sites has been incorporated into a highly robust Zr(IV)-based metal-organic framework (MOF) by postsynthetic exchange (PSE). The PSE protocol is crucial as direct solvothermal synthesis fails to produce the functionalized MOF. The m...

We investigated the alteration in l-ascorbate (AsA, reduced form) content and the expression pattern of its related genes during the phase transition in Oncidium orchid. During the vegetative growth, a high H2O2 level was associated with a high content of the reduced form of AsA. During the bolting period, the AsA content and H2O2 level were greatly reduced in parallel with increased expression...

In order to study gene expression in a reproductive organ, we constructed a cDNA library of mature flower buds in Lotus japonicus, and characterized expressed sequence tags (ESTs) of 842 clones randomly selected. The EST sequences were clustered into 718 non-redundant groups. From BLAST and FASTA search analyses of both protein and DNA databases, 58.5% of the EST groups showed significant seque...

Transporters are integral membrane proteins with central roles in the efficient movement of molecules across biological membranes. Many transporters exist as oligomers in the membrane. Depending on the individual transport protein, oligomerization can have roles in membrane trafficking, function, regulation and turnover. For example, our recent studies on UapA, a nucleobase ascorbate transporte...

Streptococcus pneumoniae, a penicillin-sensitive bacterium, is recognized as a major cause of pneumonia and is treated clinically with penicillin-based antibiotics. The rapid increase in resistance to penicillin and other antibiotics affects 450 million people globally and results in 4 million deaths every year. To unveil the mechanism of resistance of S. pneumoniae is thus an important issue t...

Effects of L-ascorbate 2-sulfate (AAS) on lipid metabolism and on pathological changes of aorta and visceral organs were investigated in cholesterol fed rabbits, with ascorbic acid (AA) and clofibrate (CPIB) as reference compounds. Administration of AAS (300 and 150 mg/kg) inhibited an increase in the levels of serum total cholesterol, free cholesterol, triglycerides and phospholipids caused by...

Fig is a very perishable fruit with short postharvest life. Low-cost techniques should be employed to reduce fresh fig losses. The purpose of this study was design passive modified atmosphere packaging (PMAP) extend the shelf-life ‘Dottato’ figs stored at 4 °C for 21 days. Physico-chemical traits and enzymatic non-enzymatic antioxidant systems were evaluated. Storage in PMAP reduced losses weig...