Molecular basis of IgE-recognition of Lol p 5, a major allergen of rye-grass pollen

Grass pollen, especially of rye-grass (Lolium perenne). represents an important cause of type I allergy. Identification of IgE-binding (allergenic) epitopes of major grass pollen allergens is essential for understanding the molecular basis of interaction between allergens and human IgE antibodies and therefore facilitates the devising of safer and more effective diagnostic and immunotherapy reagents. The aim of this study was to identify the allergenic epitopes of Lol p 5, a major allergen of rye-grass pollen, immunodissect these epitopes further so that the amino acid residues critical for antibody binding can be determined and investigate the conservation and nature of these epitopes within the context of the natural grass pollen allergens. Peptides, 12-13 amino acid residues long and overlapping each other by 4 amino acid residues, based on the entire deduced amino acid sequence of the coding region of Lol p 5, were synthesised and assayed for IgE-binding. Two strong IgE-binding epitopes (Lol p 5 (49-60) and (265-276), referred to as peptides 7 and 34, respectively) were identified. These epitopes were further resolved by truncated peptides and amino acid replacement studies and the amino acid residues critical for IgE-binding determined (Lol p 5 (49-60) residue Lys57 and (265-276) residue Lys275). Sequences of these epitopes were conserved in related allergens and may form the conserved allergenic domains responsible for the cross-reactivity observed between pollen allergens of taxonomically related grasses. Furthermore, due to its strong IgE-reactivity, synthetic peptide Lol p 5 (265-276) was used to affinity-purify specific IgE antibodies which recognised proteins of other clinically important grass pollens. further indicating presence of allergenic cross-reactivity at the level of allergenic epitope. Moreover, Lol p 5 (265 276) demonstrated a strong capacity to inhibit IgE-binding to natural rye-grass pollen proteins highlighting the antibody accessibility to these sequences within the context of the natural allergens. Strong IgE-binding epitopes of Lol p 5 have been identified down to single critical amino acid residues and are shown to occur as linear or continuous domains in the natural conformation of natural Lol p 5 and other group 5 grass pollen allergens. The fact that such an allergenic synthetic epitope has the capacity to strongly inhibit IgE-binding to natural allergens highlight its potential for use as a candidate in future therapeutics to treat pollen-associated allergies.     

The use of interactive media among today’s youth: Results of a survey

The intensive use of interactive media has led to assertions about the effect of these media on youth. This paper presents a quantitative study on the position of interactive media in young people’s lives. Rather than following the assumption of a homogeneous generation, we investigate the existence of a diversity of user patterns. The research question for this paper: Can patterns be found in the use of interactive media among youth? We answer this question by a survey among Dutch youngsters aged 10–23. Four clusters of interactive media users, namely Traditionalists, Gamers, Networkers and Producers were identified using cluster analysis. Behind these straightforward clusters, a complex whole of user activities can be found. Each cluster shows specific use of and opinions about interactive media. This provides a contextualized understanding of the position of interactive media in the lives of contemporary youth, and a nuanced conceptualization of the ‘Net generation’. This allows for studying the intricate relationship between youth culture, interactive media and learning.     

Simulating diffusions with piecewise constant coefficients using a kinetic approximation

Using a kinetic approximation of a linear diffusion operator, we propose an algorithm that allows one to deal with the simulation of a multi-dimensional stochastic process in a media which is locally isotropic except on some surface where the diffusion coefficient presents some discontinuities. Basic numerical examples are given in dimensions one to three on PDEs or stochastic PDEs with or without source terms. Finally, we compute the hydro-dynamic load in a porous media in the nuclear waste context.     

Effect of polymerization conditions on polyacetylene morphology

In an effort to optimize the synthesis of polyacetylene we have studied the evolution of its morphology by scanning electron microscopy (SEM) and also determined the density of the polymer. Both results are correlated and discussed.     

Unfurlable satellite antennas: A review

A review of unfurlable satellite antennas is presented. Typical application requirements for future space missions are first outlined. Then, US and European mesh and inflatable antenna concepts are described. Precision deployables using rigid panels or petals are not included in the survey.RF modelling and performance analysis of gored or faceted mesh reflector antennas are then reviewed. Finally, both on ground and in orbitRF test techniques for large unfurlable antennas are discussed.     

High-speed bulk InGaAsP-InP electroabsorption modulators withbandwidth in excess of 20 GHz

Bulk InGaAsP-InP electroabsorption optical modulators with high extinction ratio, low drive voltage, and high modulation bandwidth at λ=1.3 μm are reported. The devices have a tapered-fiber-to-modulator-to-tapered-fiber extinction ratio greater than 20 dB at a drive voltage of <5 V. Very low capacitance modulators (<0.2 pF) were fabricated using SiO₂ bonding pad isolation, resulting in a measured electrical modulation bandwidth in excess of 20 GHz     

Analyse des performances du codage multiniveau pour modulations à grand nombre d’états

In this paper, we analyze the performance of multilevel coding for high level QAM constellations. After the presentation of the encoder principle, we focus our study on a sub-optimal decoder which can be implemented very simply. We analyze the performance of the presented technique in terms of asymptotic gain and bit error rate characteristics. Finally, a pratical application in digital microwave radio links is considered, and one- and two-level coded 128-QAM are studied. At a bit error rate of 10^-8, it is shown that a 4 dB coding gain can be reached with moderate decoder complexity. These coding schemes are therefore very attractive for high-capacity microwave links applications.     

Species identification of red and brown seaweeds using ITS ribosomal DNA amplification and RFLP patterns

The identity of five macroalgae used as sea vegetables or food ingredients has been determined by amplification of the ribosomal DNA ITS region and RFLP analysis. This allows the detection of specificity patterns for each species and provides an alternative method, when morphological or biochemical methods fail, for control of their use as food ingredients. Alga‐specific PCR primers have been used to determine the ITS rDNA sequences of DNAs extracted from dried and ground algae up to 5 years old. The seaweeds studied were the red algae Palmaria palmata (dulse), Porphyra umbilicalis (nori), and Chondrus crispus (pioca) and the brown algae Himanthalia elongata (sea spaghetti) and Laminaria sp (konbu). Total genomic DNA suitable for amplification was extracted from the alga powder following the CTAB method. This methodology allowed the sequencing of the amplified product and the drawing of theoretical restriction maps useful in the choice of restriction enzymes for RFLP analysis. Enzymes that appeared useful included Mbo I and Alu I. Cutting with a single enzyme was sufficient to obtain characteristic patterns for the red algae P palmata, P umbilicalis and C crispus. For the two brown algae H elongata and Laminaria sp the ITS rDNA sequence showed a lack of suitable restriction site, contrary to other species for which characteristic patterns were obtained. © 2003 Society of Chemical Industry     

n−3 and n−6 fatty acid enrichment by dietary fish oil and phospholipid sources in brain cortical areas and nonneural tissues of formula-fed piglets

Sufficient availability of both n-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFA) is required for optimal structural and functional development in infancy. The question has been raised as to whether infant formulae would benefit from enrichment with 20 and 22 carbon fatty acids. To address this issue, we determined the effect of fish oil and phospholipid (LCPUFA) sources on the fatty acid composition of brain cortical areas and nonneural tissues of newborn piglets fed artificially for 2 wk. They were fed sow milk, a control formula, or the formula enriched with n-3 fatty acids from a low-20:5n-3 fish oil added at a high or a low concentration, or the formula enriched with n-3 and n-6 fatty acids from either egg yolk- or pig brain-phospholipids. Both the fish oil- and the phospholipid-enriched formula produced significantly higher plasma phospholipid 22:6n-3 concentrations than did the control formula. The 22:6n-3 levels in the brain, hepatic, and intestinal phospholipids were significantly correlated with plasma values, whereas cardiac 22:6n-3 content appeared to follow a saturable dose-response. Feeding sow milk resulted in a much higher 20:4n-6 content in nonneural tissues than did feeding formula. Supplementation with egg phospholipid increased the 20:4n-6 content in the heart, red blood cells, plasma, and intestine in comparison to the control formula, while pig brain phospholipids exerted this effect in the heart only. The addition of 4.5% fish oil in the formula was associated with a decline in 20:4n-6 in the cortex, cerebellum, heart, liver, and plasma phospholipids, whereas using this source at 1.5% limited the decline to the cerebellum, liver, and plasma. Whatever the dietary treatment, the phosphatidylethanolamine 20:4n-6 level was 10–20% higher in the brain temporal lobe than in the parietal, frontal, and occipital lobes in the temporal lobe by administering the formula enriched with egg or brain phospholipids. In conclusion, feeding egg phospholipids to neonatal pigs increased both the 22:6n-3 content in the brain and the 20:4n-6 content in the temporal lobe cortex. This source also increased the 22:6n-3 levels in nonneural tissues with only minor alterations of 20:4n-6. These data support the notion that infant formulae should be supplemented with both 22:6n-3 and 20:4n-6 rather than with 22:6n-3 alone.