Hydroxyl radical induced cross-linking between phenylalanine and 2-deoxyribose

Hydroxy radicals induce cross-linking between phenylalanine (Phe) and 2-deoxyribose (dR) via formation of corresponding free radical intermediates. The cross-linked products were separated and identified by capillary gas chromatography-mass spectrometry. When phenylalanine and 2-deoxyribose radicals were generated in a 1:1 ratio, the predominant interaction was between Phe and dR radicals while the Phe-Phe and dR-dR cross-links were less abundant. The newly discovered cross-link between 2-deoxyribose and phenylalanine may serve as a model for radiation or free radical induced cross-linking between DNA and proteins and in general between sugar moieties and amino acids.     

Radiation-induced crosslinks between thymine and phenylalanine

OH radicals generated by ionizing radiation in aqueous solutions of thymine (T) and phenylalanine (Phe) induce crosslinking between thymine and phenylalanine. The crosslinked products were isolated and characterized by capillary gas chromatography-mass spectrometry. They are formed via OH radical adducts to thymine and phenylalanine and the reaction between dissimilar radicals is greatly favoured (T-Phe:Phe-Phe:T-T = 0.46:0.14:0.05). The reaction mechanism presented may serve as a model for radiation or any free radical-induced crosslinks between DNA and proteins.     

Antioxidant Activity of 5-Hydroxytryptophan, 5-Hydroxyindole, and Dopa Against Microsomal Lipid Peroxidation and Its Dependence on Vitamin E

The antioxidant capacity of 5-hydroxy-tryptophan. 5-hydroxy-indole. and DOPA (3,4-dihydroxy-phenyI-alanine) was tested in the Fe-induced lipid peroxidation of liver microsomes of normal- and vitamin E-deficient rats, using ascorbate as a reductant. Lipid peroxidation was monitored as low-level chemilu-minescence, indicative of generation of electronically-excited states arising from the recombination of secondary lipid peroxyl radicals.     

Urinary biomarkers and the rate of DNA damage in carcinogenesis and anticarcinogenesis.

Endogenous oxidative processes are shown to generate hydrogen peroxide and .OH radicals, which react in vivo to form a variety of products. Thymidine glycol (Tg) and 8-hydroxydeoxyguanosine (8-dRG-OH) are such products. They result from the excision repair of DNA and are excreted in urine. Both products can be used as biomarkers in the dosimetry of oxidative damage to DNA. Since oxidative processes and accumulation of their effects contribute to carcinogenesis, the proposed rate-of-damage hypothesis provides a rationale for using these biomarkers in early diagnostics and in the assessment of carcinogenic and anticarcinogenic properties of diets, foods, and food components, as well as certain exogenous toxicants and agents. Approaches for measurement of urinary biomarkers of DNA damage are reviewed.     

Standardized Aronia melanocarpa extract regulates redox status in patients receiving hemodialysis with anemia

Molecular and Cellular Biochemistry - The aim of our study was to investigate the effects of one-month consumption of polyphenol-rich standardized Aronia melanocarpa extract (SAE) on redox status...     

Optical absorption spectrum of half-reduced ubiquinone

Absorption spectra in the 230–500 nm range are recorded for anionic and neutral ubisemiquinone free radicals produced by pulse radiolysis.     

Guaianolides from two subspecies of Amphoricarpos neumayeri from Montenegro

Quantitative (1)H NMR measurements revealed delta(11(13)) sesquiterpene gamma-lactones as the main constituents ( >or= 1% per weight of dried plant material) in the crude extracts of the aerial parts of Amphoricarpos neumayeri ssp. neumayeri and ssp. murbeckii from mountains Orjen and Visitor (Montenegro), respectively. Preparative silica gel chromatography afforded thirteen guai-11(13)-en-12,6alpha-olides, named amphoricarpolides (1-13), with the same relative (1alphaH,4betaH,5alphaH,7betaH) configuration of the basic skeleton. The common structural feature of lactones 2-13 was 3beta,15-dioxygenation pattern. The only exception was 1 (3-deoxyamphoricarpolide), containing a single oxygen substituent (15-OH). Eight of them exhibited an additional oxygen substituent, 9beta-OH (5 and 6), 2alpha-OH (8-12), or 2alpha-OAc (13). Compound 7 was epoxydated at 10alpha(14)-position, whereas the remaining lactones contained a 10(14) double bond.     

The effect of experience and gender on cardiovascular and metabolic responses with dynamic Tae Kwon Do exercise

This study, conducted at the Exercise Physiology Laboratory of Auburn University, AL, addressed and compared the acute cardiovascular and metabolic effects elicited by novice and experienced men and women participants during a single bout of dynamic Tae Kwon Do exercise and investigated whether or not dynamic Tae Kwon Do practice is an exercise modality that provides sufficient cardiorespiratory demand for enhancing aerobic fitness and promoting weight and fat loss. Twenty-eight men and women (aged 19-42) were assigned to 1 of the following 4 groups: Tae Kwon Do experienced and trained men (ME), Tae Kwon Do experienced and trained women (FE), novice Tae Kwon Do men (MN), and novice Tae Kwon Do women (FN). The results of this investigation indicate that this form of exercise can be performed for an extended period of 20 minutes. All 4 groups achieved the recommended stimulus for effective initiation of cardiovascular adaptations and conditioning. The mean exercise heart rate responses (88.3-92.2% of maximal heart rate [HR max]) were similar for all groups. The observed exercise intensity ranged from 67.9 to 72.1% VO2max, and no significant difference based on the experience and gender and exercise oxygen uptake could be established. Data in this study indicate a high caloric expenditure for this mode of exercise. Total caloric cost of 20 minutes of dynamic Tae Kwon Do, 194.8 and 201.6 kcal for novice women and experienced women, respectively, was significantly lower in comparison with that of their men counterparts (316.5 and 286.5 kcal, respectively), but no significant relationship between experience and energy cost was found. The conclusion of this study indicates that dynamic Tae Kwon Do is an exercise modality that can be appropriately prescribed for cardiovascular conditioning, weight control, and fat loss.