The TLR signalling adaptor TRIF/TICAM-1 has an N-terminal helical domain with structural similarity to IFIT proteins

TRIF/TICAM-1 (TIR domain-containing adaptor inducing interferon-beta/TIR domain-containing adaptor molecule 1) is the adaptor protein in the Toll-like receptor (TLR) 3 and 4 signalling pathway that leads to the production of type 1 interferons and cytokines. The signalling involves TIR (Toll/interleukin-1 receptor) domain-dependent TRIF oligomerization. A protease-resistant N-terminal region is believed to be involved in self-regulation of TRIF by interacting with its TIR domain. Here, the structural and functional characterization of the N-terminal domain of TRIF (TRIF-NTD) comprising residues 1-153 is reported. The 2.22 angstrom resolution crystal structure was solved by single-wavelength anomalous diffraction (SAD) using selenomethionine-labelled crystals of TRIF-NTD containing two additional introduced Met residues (TRIF-NTDA66M/L113M). The structure consists of eight antiparallel helices that can be divided into two subdomains, and the overall fold shares similarity to the interferon-induced protein with tetratricopeptide repeats (IFIT) family of proteins, which are involved in both the recognition of viral RNA and modulation of innate immune signalling. Analysis of TRIF-NTD surface features and the mapping of sequence conservation onto the structure suggest several possible binding sites involved in either TRIF auto-regulation or interaction with other signalling molecules or ligands. TRIF-NTD suppresses TRIF-mediated activation of the interferon-beta promoter, as well as NF-kappa B-dependent reporter-gene activity. These findings thus identify opportunities for the selective targeting of TLR3- and TLR4-mediated inflammation

Pectin at the oil-water interface: Relationship of molecular composition and structure to functionality

The present review examines how macromolecular structure and functional groups of pectin affect its functionality with particular focus on its interfacial activity. We venture into a description of the particularly complex pectin structure and describe the major building blocks and their properties. In the following section, the role of each structural parameter is discussed with particular attention to protein, degree of acetylation and methylation, molecular weight, and branching. Finally, we discuss how modification of the extraction conditions could be tailored to obtain pectin with the desired emulsification properties. It is proposed that pectin with protein content in the range of 3%, with degree of acetylation greater than 10%, molecular weight between 100 and 200 x103 g mol-1 and enriched in RG-I segments is more likely to perform well as an emulsifier. To tailor such a structure, an aqueous extraction protocol with low pH values (between 2.5-3.5) with a strong monoprotic acid (e.g., HCl) and one-step solvent precipitation should be selected. The proposed set of extraction conditions could be used as a first step towards rational design of pectin with desirable interfacial functionality

Microdevices for extensional rheometry of low viscosity elastic liquids : a review

Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations

Getting the feel of food structure with atomic force microscopy

This article describes the progress in the development of the atomic force microscope as an imaging tool and a force transducer, with particular reference to applications in food science. Use as an imaging tool has matured and emphasis is placed on the novel insights gained from the use of the technique to study food macromolecules and food colloids, and the subsequent applications of this new knowledge in food science. Use as a force transducer is still emerging and greater emphasis is given on the methodology and analysis. Where available, applications of force measurements between molecules or between larger colloidal particles are discussed, where they have led to new insights or solved problems related to food science. The future prospects of the technique in imaging or through force measurements are discussed

Thermorheological and textural behaviour of gluten-free gels obtained from chestnut and rice flours

Nowadays, as celiac disease is becoming more common the consumers’ demand for gluten-free products with high nutritional and taste quality is increasing. This work deals with the study of the impact of four novelty gluten-free sources: chestnut flour (Cf), whole rice flour (Rw), Carolino rice flour (Rc) and Agulha rice flour (Ra). Textural, thermorheological and stability performance of gluten-free gels using different experimental techniques were evaluated. Mixed gels were also produced for comparison. Texture parameters were determined from the texture profile analysis using a texturometer. Thermorheological oscillatory measurements were conducted in a stresscontrolled rheometer in order to clarify the kinetics of gel formation and to characterise the structure of the matured gels. The stability of the gels was evaluated using transmittance profiling of the gels under gravitational fields (LUMiSizer®). Texture studies suggested that gels from mixtures of chestnut flour at 30 % and rice flour at 20 % showed the right texture to develop gel-based new desserts. Rheological results showed that the thermal profiles on heating of Cf gels were similar to those obtained for Rw and Ra, whereas Rc gels exhibited a particular pattern. Once the final gelatinisation temperature was achieved, no significant differences on the viscoelastic properties were noticed for all the tested gels. Stability tests showed that gels with Rc should present an industrial advantage over the other assayed formulations, since the stability of these gels is of the order of four times larger

A cartilage tissue engineering approach combining starch-polycaprolactone fibre mesh scaffolds with bovine articular chondrocytes

In the present work we originally tested the suitability of corn starch-polycaprolactone (SPCL) scaffolds for pursuing a cartilage tissue engineering approach. Bovine articular chondrocytes were seeded on SPCL scaffolds under dynamic conditions using spinner flasks (total of 4 scaffolds per spinner flask using cell suspensions of 0.5×106 cells/ml) and cultured under orbital agitation for a total of 6 weeks. Poly(glycolic acid) (PGA) non-woven scaffolds and bovine native articular cartilage were used as standard controls for the conducted experiments. PGA is a kind of standard in tissue engineering approaches and it was used as a control in that sense. The tissue engineered constructs were characterized at different time periods by scanning electron microscopy (SEM), hematoxylin-eosin (H&E) and toluidine blue stainings, immunolocalisation of collagen types I and II, and dimethylmethylene blue (DMB) assay for glycosaminoglycans (GAG) quantification assay. SEM results for SPCL constructs showed that the chondrocytes presented normal morphological features, with extensive cells presence at the surface of the support structures, and penetrating the scaffolds pores. These observations were further corroborated by H&E staining. Toluidine blue and immunohistochemistry exhibited extracellular matrix deposition throughout the 3D structure. Glycosaminoglycans, and collagen types I and II were detected. However, stronger staining for collagen type II was observed when compared to collagen type I. The PGA constructs presented similar features toSPCLat the end of the 6 weeks. PGA constructs exhibited higher amounts of matrix glycosaminoglycans when compared to the SPCL scaffolds. However, we also observed a lack of tissue in the central area of the PGA scaffolds. Reasons for these occurrences may include inefficient cells penetration, necrosis due to high cell densities, or necrosis related with acidic by-products degradation. Such situation was not detected in the SPCL scaffolds, indicating the much better biocompatibility of the starch based scaffolds