The expression of a hunchback ortholog in the polychaete annelid Platynereis dumerilii suggests an ancestral role in mesoderm development and neurogenesis

Orthologs of the Drosophila gap gene hunchback have been isolated so far only in protostomes. Phylogenetic analysis of recently available genomic data allowed us to confirm that hunchback genes are widely found in protostomes (both lophotrochozoans and ecdysozoans). In contrast, no unequivocal hunchback gene can be found in the genomes of deuterostomes and non-bilaterians. We cloned hunchback in the marine polychaete annelid Platynereis dumerilii and analysed its expression during development. In this species, hunchback displays an expression pattern indicative of a role in mesoderm formation and neurogenesis, and similar to the expression found for hunchback genes in arthropods. These data suggest altogether that these functions are ancestral to protostomes.Pierre Kerner and Fabiola Zelada González contributed equally to this work.     

Kinetics of insulin aggregation: disentanglement of amyloid fibrillation from large-size cluster formation

Kinetics of human insulin aggregation has been studied at pH 1.6 and 60 degrees C, when amyloid fibrils are formed. We developed a novel approach based on the analysis of scattered light intensity distribution, which allows distinguishing between small and large size aggregates. By this method, we observed an exponential growth of fibrillar aggregates implying a heterogeneous aggregation mechanism. Also, the apparent lag time observed, correlated with the major increase of thioflavin T fluorescence, has been assigned to the onset of large size cluster formation.     

Protective and inhibitory effects of various types of amphipols on the Ca2+-ATPase from sarcoplasmic reticulum: a comparative study

Amphipols are amphipathic polymers designed to replace or supplement detergents in membrane protein solution studies. Previous work has suggested both advantages and disadvantages to the use of a polyacrylate-based amphipol, A8-35, for studying the sarcoplasmic reticulum Ca2+-ATPase (SERCA1a). We investigated this issue further using a set of four amphipols with different chemical structures. Previous size exclusion chromatography experiments had shown that A8-35 and SERCA1a/A8-35 complexes aggregate under certain conditions. We show here that aggregation can be prevented by omitting calcium from buffers or by using a sulfonated version of A8-35. A8-35 had previously been shown to protect Ca2+-ATPase from irreversible denaturation, while inhibiting its activity in a reversible manner. We show here that the other three amphipols tested also display these properties and that all four amphipols slow down backward calcium dissociation from the nonphosphorylated solubilized enzyme, a priori an unrelated step. As this calcium dissociation involves the opening up of the bundle of transmembrane ATPase segments, the slowing of this process may indicate that multipoint attachment of the polymers to the hydrophobic transmembrane surface damps protein dynamics ("Gulliver" effect). Damping might be the reason why amphipols also simultaneously protect membrane proteins against irreversible denaturation and may inhibit the activity of those of them that display large rearrangements of their transmembrane surface during their catalytic cycle.     

Adalimumab clinical efficacy is associated with rheumatoid factor and anti-cyclic citrullinated peptide antibody titer reduction: a one-year prospective study

Studies on autoantibody production in patients treated with tumor necrosis factor-alpha (TNF-alpha) inhibitors reported contradictory results. We investigated in a prospective study the efficacy of a treatment with human monoclonal anti-TNF-alpha antibody (adalimumab) in patients with rheumatoid arthritis (RA) and we evaluated the relationship between treatment efficacy and the incidence and titers of disease-associated and non-organ-specific autoantibodies. Fifty-seven patients with RA not responsive to methotrexate and treated with adalimumab were enrolled. Antinuclear, anti-double-stranded(ds)DNA, anti-extractable nuclear antigens, anti-cardiolipin (aCL), anti-beta2 glycoprotein I (anti-beta2GPI) autoantibodies, rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) autoantibodies were investigated at baseline and after 6 and 12 months of follow-up. Comparable parameters were evaluated in a further 55 patients treated with methotrexate only. Treatment with adalimumab induced a significant decrease in RF and anti-CCP serum levels, and the decrease in antibody titers correlated with the clinical response to the therapy. A significant induction of antinuclear autoantibodies (ANA) and IgG/IgM anti-dsDNA autoantibodies were also found in 28% and 14.6% patients, respectively, whereas aCL and anti-beta2GPI autoantibodies were not detected in significant quantities. No association between ANA, anti-dsDNA, aCL and anti-beta2GPI autoantibodies and clinical manifestations was found. Clinical efficacy of adalimumab is associated with the decrease in RF and anti-CCP serum levels that was detected after 24 weeks and remained stable until the 48th week of treatment. Antinuclear and anti-dsDNA autoantibodies, but not anti-phospholipid autoantibodies, can be induced by adalimumab but to a lower extent than in studies with other anti-TNF blocking agents.     

Elucidation of (-)-epicatechin metabolites after ingestion of chocolate by healthy humans

After absorption in the gastrointestinal tract, (-)-epicatechin is extensively transformed into various conjugated metabolites. These metabolites, chemically different from the aglycone forms found in foods, are the compounds that reach the circulatory system and the target organs. Therefore, it is imperative to identify and quantify these circulating metabolites to investigate their roles in the biological effects associated with (-)-epicatechin intake. Using authentic synthetic standards of (-)-epicatechin sulfates, glucuronides, and O-methyl sulfates, a novel LC-MS/MS-MRM analytical methodology to quantify (-)-epicatechin metabolites in biological matrices was developed and validated. The optimized method was subsequently applied to the analysis of plasma and urine metabolites after consumption of dark chocolate, an (-)-epicatechin-rich food, by humans. (-)-Epicatechin-3'-β-d-glucuronide (C(max) 290±49nM), (-)-epicatechin 3'-sulfate (C(max) 233±60nM), and 3'-O-methyl epicatechin sulfates substituted in the 4', 5, and 7 positions were the most relevant (-)-epicatechin metabolites in plasma. When plasmatic metabolites were divided into their substituent groups, it was revealed that (-)-epicatechin glucuronides, sulfates, and O-methyl sulfates represented 33±4, 28±5, and 33±4% of total metabolites (AUC(0-24)(h)), respectively, after dark chocolate consumption. Similar metabolites were found in urine samples collected over 24h. The total urine excretion of (-)-epicatechin was 20±2% of the amount ingested. In conclusion, we describe the entire metabolite profile and its degree of elimination after administration of (-)-epicatechin-containing food. These results will help us understand more precisely the mechanisms and the main metabolites involved in the beneficial physiological effects of flavanols.