Hedgehog Signalling Modulates Immune Response and Protects against Experimental Autoimmune Encephalomyelitis

The Hedgehog (Hh) pathway is essential for the embryonic development and homeostatic maintenance of many adult tissues and organs. It has also been associated with some functions of the innate and adaptive immune system. However, its involvement in the immune response has not been well determined. Here we study the role of Hh signalling in the modulation of the immune response by using the Ptch-1-LacZ^+/− mouse model (hereinafter referred to as ptch^+/−), in which the hemizygous inactivation of Patched-1, the Hh receptor gene, causes the constitutive activation of Hh response genes. The in vitro TCR stimulation of spleen and lymph node (LN) T cells showed increased levels of Th2 cytokines (IL-4 and IL-10) in ptch^+/−cells compared to control cells from wild-type (wt) littermates, suggesting that the Th2 phenotype is favoured by Hh pathway activation. In addition, CD4⁺ cells secreted less IL-17, and the establishment of the Th1 phenotype was impaired in ptch^+/− mice. Consistently, in response to an inflammatory challenge by the induction of experimental autoimmune encephalomyelitis (EAE), ptch^+/− mice showed milder clinical scores and more minor spinal cord damage than wt mice. These results demonstrate a role for the Hh/ptch pathway in immune response modulation and highlight the usefulness of the ptch^+/− mouse model for the study of T-cell-mediated diseases and for the search for new therapeutic strategies in inflammatory diseases.     

Secondary bioreceptivity of granite: effect of salt weathering on subaerial biofilm growth

Salt crystallisation is a very common and powerful weathering agent that can modify the petrophysical properties of building stone such as granite. In addition, the weathering can affect the susceptibility of the stone to biological colonisation. The aims of the present study were to examine the properties of a granite weathered by sodium chloride crystallisation and to evaluate the effects of the weathering on the secondary bioreceptivity of the stone to subaerial phototrophic biofilms. For this purpose, granite samples were subjected to a laboratory-based accelerated salt weathering test, and changes in weight, open porosity, bulk density, capillary water content, abrasion pH and surface roughness of the samples were determined. Samples of both weathered and non-weathered granite were then inoculated with a multi-species phototrophic culture derived from a natural subaerial biofilm and incubated under standardised laboratory conditions for 3 months. The weight loss produced by the weathering process was consistent with significant changes in abrasion pH and surface roughness. The bioreceptivity of the stone was also altered. According to the bioreceptivity index, the granite under study was characterised by ‘mild primary bioreceptivity’, but ‘high secondary bioreceptivity’ after the salt weathering process. Study of the secondary bioreceptivity of stone materials can provide very useful information about response to weathering effects, and the findings can be used to improve the selection of materials for building purposes.     

Self‐Propelled Activated Carbon Janus Micromotors for Efficient Water Purification

Self‐propelled activated carbon‐based Janus particle micromotors that display efficient locomotion in environmental matrices and offer effective ‘on‐the‐fly’ removal of wide range of organic and inorganic pollutants are described. The new bubble‐propelled activated carbon Janus micromotors rely on the asymmetric deposition of a catalytic Pt patch on the surface of activated carbon microspheres. The rough surface of the activated carbon microsphere substrate results in a microporous Pt structure to provide a highly catalytic layer, which leads to an effective bubble evolution and propulsion at remarkable speeds of over 500 μm/s. Such coupling of the high adsorption capacity of carbon nanoadsorbents with the rapid movement of these catalytic Janus micromotors, along with the corresponding fluid dynamics and mixing, results in a highly efficient moving adsorption platform and a greatly accelerated water purification. The adsorption kinetics and adsorption isotherms have been investigated. The remarkable decontamination efficiency of self‐propelled activated carbon‐based Janus micromotors is illustrated towards the rapid removal of heavy metals, nitroaromatic explosives, organophosphorous nerve agents and azo‐dye compounds, indicating considerable promise for diverse environmental, defense, and public health applications.     

Long‐chain fatty acid supplemented infant formula does not influence calcium and magnesium bioavailability in weanling rats

The influence of infant formula supplementation with long‐chain‐polyunsaturated fatty acids (LCPUFA) on calcium and magnesium bioavailability was assessed in rats. Two test diets containing a plain, unsupplemented (PF) or supplemented (SF) infant formula as the fat source and a control diet (C) were administered to weaning rats and food intake and body weight gain were monitored for 28 days. In order to assess calcium and magnesium bioavailability, during the last week faeces and urine were collected and apparent absorption and retention were calculated. Food intake and body weight showed no significant differences between PF and SF but were lower in both groups compared with C. Calcium and magnesium intake did not differ between PF and SF, although both parameters were lower compared with C. Calcium absorption efficiency in PF and SF was significantly higher than in C. However, both groups showed higher urinary calcium excretion and thus no differences were observed in calcium retention. Magnesium absorption efficiency was also significantly higher in PF and SF compared with C, but magnesium absorption was significantly lower in SF compared with PF and C. Nevertheless, urinary magnesium excretion and magnesium retention were similar in the three groups. The consumption of a diet containing an infant formula supplemented with LCPUFA compared with the plain formula does not affect calcium and magnesium bioavailability in rats. Copyright © 2005 Society of Chemical Industry     

Direct Determination of Saccharin and Acesulfame-K in Sweeteners and Fruit Juices Powders

A simple and rapid analytical procedure for determination of saccharin (SAC) and acesulfame-K (AC-K) based on UV-vis measurements and partial least squares (PLS) was proposed. Thus, an experimental design at levels 2 and 15 mg l⁻¹ for SAC and 2 and 20 mg l⁻¹ for AC-K was applied. Because real samples usually contain SAC and AC-K combined with aspartame (ASP), this interference was also included in the model. The procedure was successfully applied for SAC and AC-K simultaneous determination in sweeteners and fruit juice powders, without any separation step to remove ASP. The results were validated by using spiked samples, and the obtained recoveries were satisfactory.     

Ubisch bodies and pollen ontogeny in Oxalis articulata Savigny.

The correlation between the ontogeny of Ubisch bodies and pollen development in Oxalis articulata was studied with Transmission Electron Microscopy (TEM). The ultrastructural changes observed during the different stages of development in the tapetal cells are related to Ubisch bodies, sporopollenin and pollen-kitt formation. The pro-orbicules have the appearance of lipid globuli and their formation is related to the endoplasmic reticulum of rough type (ERr). The lipid globules or pro-orbicules disappear in the mature Ubisch bodies, and the places that they occupied remain free of contents or with pollen-kitt.     

Laser Heating Tunability by Off‐Resonant Irradiation of Gold Nanoparticles

Temperature changes in the vicinity of a single absorptive nanostructure caused by local heating have strong implications in technologies such as integrated electronics or biomedicine. Herein, the temperature changes in the vicinity of a single optically trapped spherical Au nanoparticle encapsulated in a thermo‐responsive poly(N‐isopropylacrylamide) shell (Au@pNIPAM) are studied in detail. Individual beads are trapped in a counter‐propagating optical tweezers setup at various laser powers, which allows the overall particle size to be tuned through the phase transition of the thermo‐responsive shell. The experimentally obtained sizes measured at different irradiation powers are compared with average size values obtained by dynamic light scattering (DLS) from an ensemble of beads at different temperatures. The size range and the tendency to shrink upon increasing the laser power in the optical trap or by increasing the temperature for DLS agree with reasonable accuracy for both approaches. Discrepancies are evaluated by means of simple models accounting for variations in the thermal conductivity of the polymer, the viscosity of the aqueous solution and the absorption cross section of the coated Au nanoparticle. These results show that these parameters must be taken into account when considering local laser heating experiments in aqueous solution at the nanoscale. Analysis of the stability of the Au@pNIPAM particles in the trap is also theoretically carried out for different particle sizes.     

Host Cell Binding Mediated by Leptospira interrogans Adhesins

Leptospirosis is a neglected infectious disease with global impact on both humans and animals. The increase in urban development without sanitation planning is one of the main reasons for the disease spreading. The symptoms are similar to those of flu-like diseases, such as dengue, yellow fever, and malaria, which can result in a misleading clinical diagnosis. The characterization of host–pathogen interactions is important in the development of new vaccines, treatments, and diagnostics. However, the pathogenesis of leptospirosis is not well understood, and many gaps remain to be addressed. Here, we aimed to determine if Leptospira strains, virulent, culture-attenuated, and saprophytic, and the major outer membrane proteins OmpL37, OmpL1, LipL21, LipL41, and LipL46 are able to adhere to different endothelial, epithelial and fibroblast cell lines in vitro. We showed that virulent leptospires robustly bind to all cells compared to the culture-attenuated and saprophytic lines. The recombinant proteins exhibited certain adhesion, but only OmpL1 and LipL41 were able to bind to several cell lines, either in monolayer or in cell suspension. Blocking OmpL1 with polyclonal antibodies caused a decrease in bacterial binding to cells, contrasting with an increase observed when anti-LipL41 antibodies were used. The adhesion of OmpL1 to HMEC-1 and EA.hy926 was inhibited when cells were pre-incubated with collagen IV, suggesting that both compete for the same cell receptor. We present here for the first time the interaction of five leptospiral outer membrane proteins with several cell lines, and we conclude that LipL41 and OmpL1 may have an impact on leptospiral adhesion to mammalian cells and may mediate the colonization process in leptospiral pathogenesis.