Model studies on reactions occurring in oxidations of lignin with molecular oxygen in Alkaline Media

Basic reactions governing the degradation of lignin in oxidation with molecular oxygen are discussed emphasizing the radical (homolytic) or one-electron transfer-oxidations in the initial phase. The critical oxidation potentials (COP) according to Fieser were found to represent a useful measure for the ease of electron release from lignin-related phenolic models. At low alkalinity rough correlations were observed between the measured COPs and the initial oxygenation rates. The results obtained from quantum mechanical calculations of critical oxidation potentials are briefly discussed.The importance of phenoxy radicals and the hypothetical cyclohexadienone hydroperoxides as intermediates is outlined in view of such degradation reactions as oxidative side-chain eliminations, demethoxylations, and splitting of aromatic rings.Research performed at the Institute of Organic Chemistry, University of Vienna.     

Dietary intake and the insulin-like growth factor system: effects of migration in two related populations in India and Britain with markedly different dietary intake

BACKGROUND: The insulin-like growth factor (IGF) system is implicated in the pathogenesis of diabetes and cardiovascular disease. OBJECTIVE: We report the effects of total energy intake on the IGF system in two populations with markedly different dietary macronutrient intake and cardiovascular event rate. DESIGN, SUBJECTS AND SETTING: Dietary macronutrient intake was measured in a specific Gujarati migrant community in Sandwell, UK (n=205) compared with people still resident in the same villages of origin in India (n=246). Fasting IGF-I, IGF-binding protein (IGFBP)-1 and IGFBP-3, insulin and glucose (0 and 2-hour) were measured. RESULTS: Total energy and total fat intake were higher in UK migrants, as were IGFBP-3 and IGF-I (mean (95% confidence interval): 145.9 (138.1-153.6) vs. 100.9 (94.6-107.3) ng ml(-1); F=76.6, P<0.001). IGFBP-1 was lower in UK migrants (29.5 (25.9-33.0) vs. 56.5 (50.6-62.5) microg l(-1); F=48.4, P<0.001). At both sites, IGF-I correlated positively with total energy (Spearman's rho=0.45, P<0.001) and total fat (rho=0.44, P<0.001) as did IGFBP-3 with total energy (rho=0.21, P<0.05) and fat (rho=0.26, P<0.001). Conversely, in Indian Gujaratis, IGFBP-1 fell with increasing total energy (rho=-0.27, P<0.001) and fat intake (rho=-0.26, P<0.01) but not in UK Gujaratis. Multiple linear regression modelling showed that increasing quartiles of fat intake were associated with higher IGF-I (beta=0.42, P=0.007) independent of age, body mass index, plasma insulin, fatty acids and 2-hour glucose. CONCLUSION: In these genetically similar groups, migration to the UK and adoption of a different diet is associated with marked changes in the IGF system, suggesting that environmental factors profoundly modulate serum concentrations and actions of IGFs.     

cDNA cloning and characterization of the warm-temperature-acclimation-associated protein Wap65 from carp, Cyprinus carpio

We determined full-length cDNA of carp warm-temperature-acclimation-associated 65-kDa protein (Wap65). It encoded 439 amino acid residues with a signal peptide of 22 residues and showed an amino acid sequence identity of 88% to that of goldfish reported before (J. Biol. Chem. 1995. 270: 17087–17092). The number of potential N-linked glycosylation sites of carp Wap65 was two in contrast to three for goldfish. In addition, molecular mass determined by SDS-PAGE was apparently different from that of goldfish. These results suggest that the amount of oligosaccharide is different between the carp and goldfish protein. As in goldfish, carp Wap65 mRNA showed marked accumulation in hepatopancreas of the 30 °C- acclimated fish, which was 8-fold higher than that of the 10 °C-acclimated fish. Carp Wap65 showed 30% amino acid identity to mammalian hemopexins, which appeared to be considerably low in comparison with those among mammalian hemopexins (72 to 80%), or among carp Wap65 and rainbow trout hemopexin-like protein (70%). However, although mammalian hemopexins contain residues comprising the heme binding pocket, carp Wap65 lacked one of the two histidine residues to serve as heme axial ligands in hemopexins. Our data on carp protein substantiates the previous observation for goldfish and indicates that Wap65 might have some important functions in warm-temperature-acclimation of fish.