Study of tropaeolin degradation by iron--proposition of a reaction mechanism

The degradation of tropaeolin by iron was studied under oxidizing and inert atmospheres. The products were identified by various chromatographic and spectroscopic methods. Under inert atmosphere, the proposed model of mechanism is based on the adsorption of tropaeolin by the sulfonate function on the solid iron, followed by a reduction of the –N=N– bond with formation of 1-amino-2-naphthol and sulfanilic acid. These two intermediaries were reduced to 1,2-dihydroxynaphthalene and benzene with NH₄⁺ and HSO₃⁻ liberation. Under oxidizing atmosphere, besides the reductions of tropaeolin, water and ferric ions, the existence of a homogeneous degradation was found. This process was explained (on the basis of surface iron potential monitoring) by a stepwise reduction of oxygen giving hydrogen peroxide. The initial stages of the mechanism were similar to those under inert atmosphere, but the degradation of the 1,2-dihydroxynaphthalene continued giving 1,2-naphthalenedione, then various polar monocyclic compounds leading to three unidentified volatile final products.     

SNPs of the FADS Gene Cluster are Associated with Polyunsaturated Fatty Acids in a Cohort of Patients with Cardiovascular Disease

Polymorphisms of the human Δ-5 (FADS1) and Δ-6 (FADS2) desaturase genes have been recently described to be associated with the level of several long-chain n-3 and n-6 polyunsaturated fatty acids (PUFAs) in serum phospholipids. We have genotyped 13 single nucleotide polymorphisms (SNPs) located on the FADS1–FADS2–FADS3 gene cluster (chromosome 11q12–13.1) in 658 Italian adults (78% males; mean age 59.7 ± 11.1 years) participating in the Verona Heart Project. Polymorphisms and statistically inferred haplotypes showed a strong association with arachidonic acid (C20:4n-6) levels in serum phospholipids and in erythrocyte cell membranes (rs174545 adjusted P value for multiple tests, P < 0.0001 and P < 0.0001, respectively). Other significant associations were observed for linoleic (C18:2n-6), alpha-linolenic (C18:3n-3) and eicosadienoic (C20:2n-6) acids. Minor allele homozygotes and heterozygotes were associated to higher levels of linoleic, alpha-linolenic, eicosadienoic and lower levels of arachidonic acid. No significant association was observed for stearidonic (C18:4n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids levels. The observed strong association of FADS gene polymorphisms with the levels of arachidonic acid, which is a precursor of molecules involved in inflammation and immunity processes, suggests that SNPs of the FADS1 and FADS2 gene region are worth studying in diseases related to inflammatory conditions or alterations in the concentration of PUFAs. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A melanocortin 1 receptor (MC1R) gene polymorphism is useful for authentication of Massese sheep dairy products

Massese is an Italian sheep breed, with black or grey coat colour, mainly reared in the Tuscany and Emilia Romagna regions. Recently, the emerging interests in this breed have resulted in the production of Pecorino cheese obtained with only Massese milk. In order to be profitable, this marketing link between Massese breed and its products should be defended against fraudsters who could include milk of other sheep breeds or cow milk in Massese labelled productions. To identify the genetic factors affecting coat colour in sheep, we have recently analysed the melanocortin 1 receptor (MC1R) gene and identified several single nucleotide polymorphisms (SNPs). In this work, as a first step to set up a DNA based protocol for authentication of Massese dairy products, we further investigated the presence and distribution of one of these SNPs (c.-31G>A) in 143 Massese sheep and in another 13 sheep breeds (for a total of 351 animals). The Massese breed was fixed for allele c.-31A, whereas in all other breeds allele c.-31 G was the most frequent or with frequency of 0?·50. At the same nucleotide position the cattle MC1R gene carries the G nucleotide. Using these data we developed a method to detect adulterating milk (from other sheep breeds or from cow) in Massese dairy products based on the analysis of the c.-31G>A SNP. We first tested the sensitivity of the protocol and then applied it to analyse DNA extracted from ricotta and Pecorino cheese obtained with only Massese milk or obtained with unrestricted sheep and cattle milk. To our knowledge, this system represents the first one that can be used for breed authentication of a sheep production and that, at the same time, can reveal frauds derived from the admixture of milk of an unreported species.     

Mixtures of whey protein microgels and soluble aggregates as building blocks to control rheology and structure of acid induced cold-set gels

Whey proteins (WP) today offer an extremely high potential for innovative development of functional and nutritious food products. Acid cold-set gels present an interesting approach of gelation at low temperature upon acidification of preformed whey protein (WP) aggregates. In the present work, we aimed to demonstrate how structure and rheological properties of acid gels can be controlled by combining two types of WP aggregates with different structural and chemical properties. Whey protein microgels (WPM) and soluble aggregates (WPSA) were generated upon heating WP isolate in specific pH conditions and temperature, leading to Z-average hydrodynamic diameters close to 270 nm for WPM and 100 nm for WPSA. Mixtures of WPM and WPSA were prepared at different weight ratios ranging from 100% WPM to 100% WPSA. The total protein concentration was set to 4 or 8%wt. Acidification was performed at 40 °C by addition of 1%wt glucono-δ-lactone (GDL). Gelation was followed using turbidimetry and small deformation rheology as function of pH. Microstructures of the gel were investigated at different length scales using various microscopy techniques (CLSM, SEM, AFM). When the WPM/WPSA ratio decreased, the pH of gelation and the gel strength increased because of the different structure and chemical reactivity of the two types of WP aggregates. The final pH had a strong impact on the structure of the gels. When final pH decreased below pH 4.3, a structure change was suggested by turbidimetry measurements. This resulted in a non self-supporting gel or in a decrease of gel strength. For pH above 4.3, self supporting gel were obtained. The rheological properties of the gel could therefore be modulated depending on the properties of the building blocks used (WPM versus WPSA). Interestingly, the gel microstructures observed for WPM/WPSA mixtures or WPM were comparable to those of acidified skimmed milk gels ranging from coarse structures with clumps of aggregates or to homogeneous fine networks (WPSA only) that have been described for WP gels obtained upon direct heating at various pH.     

Effects of tillage and nitrogen fertilisation on triticale grain yield,chemical composition and nutritive value

BACKGROUND: Given the interest in the development of cultivation systems with low agronomic input and environmental impact, the aim of this study was to determine the influence of tillage system (conventional tillage (CT), two‐layer tillage (TT), surface tillage (ST) and minimum tillage (MT)) and nitrogen (N) fertilisation rate (0, 50 and 100 kg ha^?1) on triticale grain and protein yields, chemical composition and nutritive value. RESULTS: There were no significant differences among tillage treatments in grain and protein yields. ST resulted in significantly higher crude protein (CP) and true soluble protein (TSP) contents as well as in vitro crude protein digestibility (CPD). Neutral detergent fibre concentration was significantly higher with ST than with MT, and this led to a small reduction (2 g kg^?1 dry matter (DM)) in in vitro true DM digestibility (IVTDMD). N fertilisation significantly increased grain and protein yields as well as CP, non‐protein nitrogen and TSP contents and CPD. IVTDMD was significantly lower with 0 kg N ha^?1 than with 50 and 100 kg N ha^?1. CONCLUSION: Reducing tillage intensity improved the CP content and CPD of triticale grain. The application of 50 kg N ha^?1 resulted in good grain quality parameters and grain and protein yields. Copyright © 2010 Society of Chemical Industry     

A model of post-combustion and heat transfer at smelting reduction with a foamy slag

A smelting reduction reactor with post-combustion in a foamy stag has two slag layers. In the lower, iron oxide from the slag is reduced to iron by carbon. In the upper, the gas from the reduction is post-combusted to CO₂+H₂O. The post-combustion heat is transferred from the rising post-combustion gas to the upper slag, and, therefrom, by slag circulation to the lower slag layer where the endothermic reduction reaction takes place. Unavoidably, slag circulation also transfers part of the char into the upper slag where it is oxidised. A kinetic post-combustion and heat transfer model describes these phenomena. The main process parameters, namely real post-combustion degree, carbon oxidation, heat transfer efficiency, distribution of temperatures of gas and slag in the single regions of the reactor, coal consumption, and iron production rate are given as functions of the ratio of post-combustion oxygen to gas evolution rate of the system. The main influences on which heat efficiency and off-gas temperature as the most important output parameter depend are discussed. Controlled stirring and a regular gas through-put are of primary importance. The required values are given. A comparison with pilot plant results of the CSM process shows good agreement with the model results.     

Phenotypic analysis of random hns mutations differentiate DNA-binding activity from properties of fimA promoter inversion modulation and bacterial motility

H-NS is a major Escherichia coli nucleoid-associated protein involved in bacterial DNA condensation and global modulation of gene expression. This protein exists in cells as at least two different isoforms separable by isoelectric focusing. Among other phenotypes, mutations in hns result in constitutive expression of the proU and fimB genes, increased fimA promoter inversion rates, and repression of the flhCD master operon required for flagellum biosynthesis. To understand the relationship between H-NS structure and function, we transformed a cloned hns gene into a mutator strain and collected a series of mutant alleles that failed to repress proU expression. Each of these isolated hns mutant alleles also failed to repress fimB expression, suggesting that H-NS-specific repression of proU and fimB occurs by similar mechanisms. Conversely, alleles encoding single amino acid substitutions in the C-terminal DNA-binding domain of H-NS resulted in significantly reduced affinity for DNA yet conferred a wild-type fimA promoter inversion frequency, indicating that the mechanism of H-NS activity in modulating promoter inversion is independent of DNA binding. Furthermore, two specific H-NS amino acid substitutions resulted in hypermotile bacteria, while C-terminal H-NS truncations exhibited reduced motility. We also analyzed H-NS isoform composition expressed by various hns mutations and found that the N-terminal 67 amino acids were sufficient to support posttranslational modification and that substitutions at positions 18 and 26 resulted in the expression of a single H-NS isoform. These results are discussed in terms of H-NS domain organization and implications for biological activity.     

Study of the Spatio-Chemical Heterogeneity of Tannin-Furanic Foams: From 1D FTIR Spectroscopy to 3D FTIR Micro-Computed Tomography

Tannin-furanic rigid foams are bio-based copolymers of tannin plant extract and furfuryl alcohol, promising candidates to replace synthetic insulation foams, as for example polyurethanes and phenolics, in eco-sustainable buildings thanks to their functional properties, such as lightness of the material and fire resistance. Despite their relevance as environmental-friendly alternatives to petroleum derivatives, many aspects of the polymerization chemistry still remain unclear. One of the open issues is on the spatial heterogeneity of the foam, i.e., whether the foam constituents prevalently polymerize in spatially segregated blocks or distribute almost homogenously in the foam volume. To address this matter, here we propose a multiscale FTIR study encompassing 1D FTIR spectroscopy, 2D FTIR imaging and 3D FTIR micro-tomography (FTIR-μCT) on tannin-furanic rigid foams obtained by varying the synthesis parameters in a controlled way. Thanks to the implementation of the acquisition and processing pipeline of FTIR-μCT, we were able for the first time to demonstrate that the polymer formulations influence the spatial organization of the foam at the microscale and, at the same time, prove the reliability of FTIR-μCT data by comparing 2D FTIR images and the projection of the 3D chemical images on the same plane.