The dibenzodioxocin lignin substructure is abundant in the inner part of the secondary wall in Norway spruce and silver birch xylem

A specific condensed lignin substructure, dibenzodioxocin, was immunolocalized in differentiating cell walls of Norway spruce (Picea abies (L.) H. Karsten) and silver birch (Betula pendula Roth) xylem. A fluorescent probe, Alexa 488 was used as a marker on the dibenzodioxocin-specific secondary antibody. For the detection of this lignin substructure, 25-m cross-sections of xylem were viewed with a confocal laser-scanning microscope with fluorescein isothiocyanate fluorescence filters. In mature cells, fluorescence was detected in the S3 layer of the secondary wall in both tree species, but it was more intense in Norway spruce than in silver birch. In silver birch most of the signal was detected in vessel walls and less in fiber cell walls. In very young tracheids of Norway spruce and vessels and fibers of silver birch, where secondary cell wall layers were not yet formed, the presence of the dibenzodioxocin structure could not be shown.Abbreviation CLSM confocal laser-scanning fluorescence microscopy     

Role of solvent parameters in the regeneration of cellulose from ionic liquid solutions

The ionic liquids 1-ethyl-3-methylimidazolium acetate [emim]OAc, N,N,N,N-tetramethylguanidium propionate [TMGH]EtCO(2), and N,N,N,N-tetramethylguanidium acetate [TMGH]OAc, and the traditional cellulose solvent N-methylmorpholine N-oxide NMMO were characterized for their Kamlet-Taft (KT) values at several water contents and temperatures. For the ionic liquids and NMMO, thresholds of regeneration of cellulose solutions by water were determined using nephelometry and rheometry. Regeneration from wet IL was found to be asymmetric compared to dissolution into wet IL. KT parameters were found to remain almost constant at temperatures, between 20-100 °C, even at different water contents. Among the KT parameters, the β value was found to change most drastically, with an almost linear decrease upon addition of water. The ability of the mixtures to dissolve cellulose was best explained by the difference β-α (net basicity), rather than β alone. Regeneration of cellulose starts at thresholds values of approximately β < 0.8 (β-α < 0.35) and displayed four phases.     

The peptide-substrate-binding domain of human collagen prolyl 4-hydroxylases. Backbone assignments,secondary structure,and binding of proline-rich peptides

The collagen prolyl 4-hydroxylases (C-P4Hs) catalyze the formation of 4-hydroxyproline by the hydroxylation of proline residues in -Xaa-Pro-Gly-sequences. The vertebrate enzymes are alpha 2 beta 2 tetramers in which protein-disulfide isomerase serves as the beta subunit. Two isoforms of the catalytic alpha subunit have been identified and shown to form [alpha(I)]2 beta 2 and [alpha(II)]2 beta 2 tetramers, the type I and type II C-P4Hs, respectively. The peptide-substrate-binding domain of type I C-P4H has been shown to be located between residues 138 and 244 in the 517-residue alpha(I) subunit and to be distinct from the catalytic domain that is located in the C-terminal region. We report here that a recombinant human C-P4H alpha(I) polypeptide Phe144-Ser244 forms a folded domain consisting of five alpha helices and one short beta strand. This structure is quite different from those of other proline-rich peptide-binding modules, which consist mainly of beta strands. Binding of the peptide (Pro-Pro-Gly)2 to this domain caused major chemical shifts in many backbone amide resonances, the residues showing the largest shifts being mainly hydrophobic, including three tyrosines. The Kd values determined by surface plasmon resonance and isothermal titration calorimetry for the binding of several synthetic peptides to the alpha(I) and the corresponding alpha(II) domain were very similar to the Km and Ki values for these peptides as substrates and inhibitors of the type I and type II C-P4H tetramers. The Kd values of the alpha(I) and alpha(II) domains for (Gly-Pro-4Hyp)5 were much higher than those for (Pro-Pro-Gly)5, indicating a marked decrease in the affinity of hydroxylated peptides for the domain. Many characteristic features of the binding of peptides to the type I and type II C-P4H tetramers can thus be explained by the properties of binding to this domain rather than the catalytic domain.     

Physical activity attenuates the influence of FTO variants on obesity risk: a meta-analysis of 218,166 adults and 19,268 children

Background

The FTO gene harbors the strongest known susceptibility locus for obesity. While many individual studies have suggested that physical activity (PA) may attenuate the effect of FTO on obesity risk, other studies have not been able to confirm this interaction. To confirm or refute unambiguously whether PA attenuates the association of FTO with obesity risk, we meta-analyzed data from 45 studies of adults (n = 218,166) and nine studies of children and adolescents (n = 19,268).

Methods and Findings

All studies identified to have data on the FTO rs9939609 variant (or any proxy [r ²>0.8]) and PA were invited to participate, regardless of ethnicity or age of the participants. PA was standardized by categorizing it into a dichotomous variable (physically inactive versus active) in each study. Overall, 25% of adults and 13% of children were categorized as inactive. Interaction analyses were performed within each study by including the FTO×PA interaction term in an additive model, adjusting for age and sex. Subsequently, random effects meta-analysis was used to pool the interaction terms. In adults, the minor (A−) allele of rs9939609 increased the odds of obesity by 1.23-fold/allele (95% CI 1.20–1.26), but PA attenuated this effect (p _interaction  = 0.001). More specifically, the minor allele of rs9939609 increased the odds of obesity less in the physically active group (odds ratio  = 1.22/allele, 95% CI 1.19–1.25) than in the inactive group (odds ratio  = 1.30/allele, 95% CI 1.24–1.36). No such interaction was found in children and adolescents.

Conclusions

The association of the FTO risk allele with the odds of obesity is attenuated by 27% in physically active adults, highlighting the importance of PA in particular in those genetically predisposed to obesity. Please see later in the article for the Editors'' Summary