Triterpenoids from Lawsonia alba.

Two pentacyclic triterpenoids have been isolated from the aerial parts of Lawsonia alba. The structures of the new constituents, named as lawsonic acid and lawsonin have been elucidated as 3 alpha-E-ferulyloxy-lup-20(29)-en-28-oic acid and 3 alpha-E-ferulyloxy-urs-11-en-13 beta-ol respectively through spectroscopic studies.     

Intricate knots in proteins: Function and evolution

Our investigation of knotted structures in the Protein Data Bank reveals the most complicated knot discovered to date. We suggest that the occurrence of this knot in a human ubiquitin hydrolase might be related to the role of the enzyme in protein degradation. While knots are usually preserved among homologues, we also identify an exception in a transcarbamylase. This allows us to exemplify the function of knots in proteins and to suggest how they may have been created.     

Influence of Selenium on Mast Cell Mediator Release

Selenium supplementation still enhanced the immune response even in individuals who, according to current standards, would be considered as not being overtly selenium deficient. Mast cells are granulated cells that play a pivotal role in allergic reactions. In this study, we investigated the modulatory effect of sodium selenite on mediator release and degranulation of murine mast cell line (MC/9). Cells were pre-treated with selenium selenite (1, 2, 3 μg/ml) for 24 h and controls left untreated. Then, cells were sensitized overnight with anti-dinitrophenyl (DNP) IgE and challenged with DNP/HSA for degranulation induction. The histamine and prostaglandin D2 (PGD2) were measured by ELISA, and β-hexosaminidase was measured by spectrophotometery method. Selenium-treated cells revealed significant decrease in concentration of PGD2 (P?=?0.019) and β-hexosaminidase (P?=?0.009). In addition, a slight reduction of histamine release by the selenium-treated cells was observed, based on our intracellular and extracellular assessments. The most inhibitory effect of selenium supplementation on mediator release of MC/9 cells was obtained in the presence of 3 μg/ml of sodium selenite. The results of the present study demonstrate beneficial effects of supplemental selenium in attenuating clinical manifestations of allergy and asthma.     

Untangling influences of hydrophobicity on protein sequences and structures

We perform a statistical analysis of solvent accessibility and hydrophobicity profiles of a representative set of proteins. The joint probability distribution is well fitted to a multivariable Gaussian, which takes a relatively simple form when expressed in terms of the Fourier transforms of the profiles. This allows us to quantify the asymmetric manner by which these profiles influence each other. For example, the α‐helix periodicity in sequence hydrophobicity is dictated by the solvent accessibility of structures, and not vice versa, possibly indicating the faster evolution of sequences compared to structures. The decorrelated hydrophobicity and solvent accessibility profiles show distinct behaviors at long periods, where sequence hydrophobicity fluctuates less, while solvent accessibility fluctuates more than average. The correlations between the two profiles can be interpreted as the Boltzmann weight of the solvation energy at room temperature, consistent with earlier observations. Proteins 2006. © 2005 Wiley‐Liss, Inc.     

A Stevedore's Protein Knot

Protein knots, mostly regarded as intriguing oddities, are gradually being recognized as significant structural motifs. Seven distinctly knotted folds have already been identified. It is by and large unclear how these exceptional structures actually fold, and only recently, experiments and simulations have begun to shed some light on this issue. In checking the new protein structures submitted to the Protein Data Bank, we encountered the most complex and the smallest knots to date: A recently uncovered α-haloacid dehalogenase structure contains a knot with six crossings, a so-called Stevedore knot, in a projection onto a plane. The smallest protein knot is present in an as yet unclassified protein fragment that consists of only 92 amino acids. The topological complexity of the Stevedore knot presents a puzzle as to how it could possibly fold. To unravel this enigma, we performed folding simulations with a structure-based coarse-grained model and uncovered a possible mechanism by which the knot forms in a single loop flip.     

Effects of Influenza Derived Peptide on CD8 T Cell Responses to MHC Class I-Restricted Human Telomerase Reverse Transcriptase (hTERT)-Derived Peptide

International Journal of Peptide Research and Therapeutics - Tumor cells in breast cancer are immunogenic and express proteins that can induce immune responses. One important antigen is human...     

Serum selenium concentration in healthy children living in Tehran

INTRODUCTION: Selenium is one of the essential trace elements which is more notified in children in recent years. Reliable age-specific reference values for selenium in children in Iran are not clear and are important for the identification of selenium deficiency and some other researches that is the aim of this study. METHODS: Serum samples of 216 healthy children were analyzed by using hydride generation and flame atomic absorption spectroscopy to measured selenium level. RESULTS: The mean and standard deviation of serum selenium level in children 0-16 years old (mean: 39.83 months) was 72.14+/-16.80 microg/l. There was significant difference in serum selenium concentration between two sexes which was 76.78+/-15.24 microg/l and 69.56+/-17.09 microg/l in girls and boys respectively (P value=0.002). There was also a positive correlation between higher selenium serum concentration and age in both sexes. CONCLUSION: Essential trace element's normal ranges are fundamental data which could use in many studies. Serum selenium concentration in healthy Iranian children that found in this study is very close to serum concentration of European children. Our findings may reveal nutritional culture's similarity.     

Effect of environmental pollution on the proteins, allergenic bands, ontogeny and structure of Avicennia marina (Forsk.) Vierh (Avicenniaceae) pollen grains

In Bushehr province of Iran, Avicennia marina trees have grown in Bordekhoon (Mond Protected Area) and Assaluyeh (Marine National Park of Nayband). Contrary to Bordekhoon, Assaluyeh is a petrochemical region with environmental pollution. This study was aimed to studying protein profiles, allergenic bands, ontogeny, structure and elemental composition of tectum of A. marina pollens in Assaluyeh and Bordekhoon. Pollens were collected from two regions and extracted in PBS, and protein profiles of pollens were determined by sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). As an experimental model, 20 female 6–8-week-old Balb/C mice were divided into two groups. The mice of first and second groups were sensitized by Bordekhoon and Assaluyeh pollen extracts, respectively, and mice serum samples were used for immunoblotting. Pollen characteristics were studied using light and scanning electron microscopes. SDS-PAGE showed some differences between pollen protein profiles of two regions. Immunoblotting assay detected that pollens have two allergenic bands and the protein band at 100 KD is the common allergenic protein in two regions. Light microscopy revealed that the development of anther wall was basic type and some abnormalities were observed in microspores and pollens of Assaluyeh. Scanning electron microscopy studies showed that the apertures in considerable numbers of Assaluyeh pollens were closed. The comparison of elemental composition of pollen tectum between two regions showed that pollens of Assaluyeh have accumulated Cu on their tectum. Results obtained indicated that environmental pollution can affect protein profile, allergenic bands, structure and elemental composition of tectum of A. marina pollens.