Peptides from Pisum sativum L. enzymatic protein digest with anti‐adhesive activity against Helicobacter pylori: Structure–activity and inhibitory activity against BabA,SabA, HpaA and a fibronectin‐binding adhesin

Scope: Identification of anti‐adhesive peptides against Helicobacter pylori obtained by enzymatic hydrolysis of seed proteins from Pisum sativum L. (Fabaceae). Methods and results: Bioassay‐guided fractionation of protein tryptic digest by ultrafiltration, size exclusion chromatography (SEC) and reversed phase chromatography (RPC) were used. Identification of bioactive peptides was achieved by MALDI‐TOF‐MS. Adhesion of H. pylori was monitored by two different assays, using a quantitative in vitro assay on human AGS cells with evaluation of bacterial binding by flow cytometry, beside a semi‐quantitative in situ adhesion assay using FITC‐labelled H. pylori on human stomach tissue sections. From two highly active fractions (F3, F3.3) two anti‐adhesive peptides (S3, S5) were identified. Neither F3 nor S3 or S5 had any cytotoxic effect against H. pylori. By hemagglutination assay and semiquantitative dot blot overlay assay with immobilized ligands it was shown that F3 interacts specifically with H. pylori adhesins BabA, SabA, HpaA and a fibronectin‐binding adhesin, while S3 and S5 inhibit only BabA. It was demonstrated that BabA, usually interacting with carbohydrate motifs such as fucosylated blood group antigens, interacts with the peptide moieties. Conclusion: Bioactive peptides from pea protein could be applied as functional ingredients for protecting infants and children against infections such as H. pylori.     

The Friendly Skies: Made Friendlier with Precise Uninterruptible Power

On-line real-time computer and data processing systems such as United Air Lines' Denver Computer Center have many and varying needs. Not only must the electrical power supply be continuous and disturbance-free, but the environmental support systems must not fail. This paper describes a facility, unattended for long periods, which provides for the needs of the people and the expensive equipment associated with that system, even if all outside utilities (except for communications) are lost. The facility, while dually functioning as a dynamic uninterruptible power supply as well as a total energy plant, has been described by some as ``The Friendly Skies' Best Friend.'     

Whole genome scan for habitat-specific genes by signature-tagged mutagenesis

Large numbers of new open reading frames can be identified by whole genome sequencing of microbial genomes. Efficient new approaches are required to investigate the role of the putative genes, or to identify genes required in distinct habitats. The novel technique 'signature-tagged mutagenesis' allows the identification of individual mutants within complex pools of mutants. Large numbers of mutants can be analyzed in a parallel manner for negative phenotypes like loss of function or attenuation of virulence. Further analysis of mutations identified by a negative selection procedure can be performed by linking the position of the respective mutations to genes identified by whole genome sequencing of microbes.     

Evaluation of a Yersinia adhesion gene (yadA) specific PCR for the identification of enteropathogenic Yersinia enterocolitica

A total of 101 Yersinia enterocolitica strains was investigated with a PCR assay [Blais and Phillipe, Food Control, 6 (1995) 211-214] targeting the Yersinia adhesin gene (yadA) responsible for autoagglutination. Compared to the autoagglutination test the PCR assay has a specificity of 100% but a sensitivity of only 70%. This failure might be caused by the sequence heterogeneity of yadA.     

Antiadhesion as a functional concept for prevention of pathogens: N-Phenylpropenoyl-L-amino acid amides as inhibitors of the Helicobacter pylori BabA outer membrane protein

Scope: Besides flavan‐3‐ols, a family of N‐phenylpropenoyl‐L ‐amino acids (NPAs) has been recently identified as polyphenol/amino acid conjugates in the seeds of Theobroma cacao as well as in a variety of herbal drugs. NPAs were shown to exhibit antiadhesive activities against Helicobacter pylori. Methods and results: For structure/activity relationship 24 homologous NPAs (2 mM) were investigated in a flow cytometric assay on potential antiadhesive effects against H. pylori adhesion to human gastric AGS cells. Dihydroxylation of the aromatic molecule part was shown to be necessary for activity; methoxylation decreases activity. High polarity of the amino acid is a prerequisite for activity. The model compound N‐(E)‐caffeoyl‐L ‐glutamic acid 11 exerted a concentration‐dependent inhibition of bacterial adhesion with saturation at 30% inhibition level. The antiadhesive effect was additionally confirmed by in situ adhesion assay on intact human gastric tissue. NPAs exhibited no cytotoxicity. Using immobilized ligands interaction 11 with bacterial adhesin BabA was demonstrated. RT‐PCR indicated that the inhibition of BabA is not correlated with subsequent feed back regulations to express more adhesins or virulence factors (vacA, cagA, cagL, cagα, fucT, ureI, ureA, OMPs). The interaction of bacterial adhesins with the respective ligands does not automatically lead to a subsequent signal transduction towards induction of virulence processes. Conclusion: The nutritional use of NPA‐containing food may justify a positive antiadhesive effect against the recurrence of H. pylori infections.     

The Open City and the e[ad] School of Architecture and Design

Located in Ritoque on central Chile's Pacific coast, Open City is a unique community established in the 1970s by faculty members from the nearby e[ad] school of architecture at the Pontifical Catholic University of Valparaíso. Here Professor David Jolly Monge , a founding member of the Open City, and Guest-Editors Christian Hermansen Cordua and Michael Hensel describe how the construction of structures on the site offer the collective community and students alike ongoing opportunities for ‘thinking, research and experimentation’.