Edited by Renee TsolisKeywords: Bacterial adhesion a-Mannoside inhibitor HT-29 cell Cytotoxicity Anti-adhesion therapy Type 1 fimbriated E. coli a b s t r a c t Bacterial adhesion to glycosylated surfaces is a key issue in human health and disease. Inhibition of bacterial adhesion by suitable carbohydrates could lead to an anti-adhesion therapy as a novel approach against bacterial infections. A selection of five a-mannosides has been evaluated as inhibitors of bacterial adhesion to the polysaccharide mannan, as well as to the surface of live human HT-29 cells. Cell toxicity studies were performed to identify the therapeutic window for a potential in vivo-application of the tested carbohydrates. A previously published mannosidic squaric acid diamide was shown to be exceptionally effective as inhibitor of the bacterial lectin FimH.

SummaryIn order to allow spatial and temporal control of carbohydrate-specific bacterial adhesion, it has become our goal to synthesise azobenzene mannosides as photoswitchable inhibitors of type 1 fimbriae-mediated adhesion of E. coli. An azobenzene mannobioside 2 was prepared and its photochromic properties were investigated. The E→Z isomerisation was found to be highly effective, yielding a long-lived (Z)-isomer. Both isomers, E and Z, show excellent water solubility and were tested as inhibitors of mannoside-specific bacterial adhesion in solution. Their inhibitory potency was found to be equal and almost two orders of magnitude higher than that of the standard inhibitor methyl mannoside. These findings could be rationalised on the basis of computer-aided docking studies. The properties of the new azobenzene mannobioside have qualified this glycoside to be eventually employed on solid support, in order to fabricate photoswitchable adhesive surfaces.

Photoaffinity labeling is frequently employed for the investigation of ligand–receptor interactions in solution. We have employed an interdisciplinary methodology to achieve facile photolabeling of the lectin FimH, which is a bacterial protein, crucial for adhesion, colonization and infection. Following our earlier work, we have here designed and synthesized diazirine-functionalized mannosides as high-affinity FimH ligands and performed an extensive study on photo-crosslinking of the best ligand (mannoside 3) with a series of model peptides and FimH. Notably, we have employed high-performance mass spectrometry to be able to detect radiation results with the highest possible accuracy. We are concluding from this study that photolabeling of FimH with sugar diazirines has only very limited success and cannot be regarded a facile approach for covalent modification of FimH.

A 0‐3 nanocomposite of CdSe (crystalline nanoparticles) and Cr2Se3 (amorphous matrix) was synthesized via a soft chemical approach and characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Particularly the transformation of the 0‐3 composite is explored in situ under electron beam irradiation and thermal annealing inside the TEM. In situ electron beam irradiation removed exclusively the CdSe nanoparticles and generated a porous Cr2Se3 matrix with a slightly increased crystallinity. The highly localized beam heating and knock‐on effect are attributed to the origin of the in situ irradiation transformation. During the in situ thermal annealing process of the 0‐3 nanocomposite CdSe particles are eliminated and crystalline nano‐ and microparticles of Cr2Se3 are generated. Also the formation of chromium enriched crystallites is observed. All of these in situ results are compared with conventional ex situ methods and discussed in terms of the different mechanisms associated with electron beam interaction and size effects of the nanocomposite.

Zusammenfassung: In derChemieist dieSynthesevon che-mischenV erbindungeni mL abor einz entralerA spekt, wenngleich dieser häufig langwierigu nd kostspieligi st. Dank immerl eistungsfähigererC omputeru nd immerb es-sererS oftwareu nd Algorithmenw erdenM oleküle längst nichtm ehrn ur praktisch-experimentellu ntersucht. Es kçnnen beispielsweise Eigenschaften, Bewegungen und Reaktionen am Computer simuliertu nd vorausgesagt werden.D ie theoretische Chemie ists omit einu nverzicht-baresT eilgebietd er Chemie.I nd iesemA rtikel wird ein Versuchv orgestellt,d er dieS imulationv on Moleküleni n derSchuleund im Chemiestudiumermçglicht. Alskonkre-tesBeispielwerdenMoleküle untersucht,die dasAnhaften von E. coli-Bakterien an menschlicheZ ellenv erhindern kçnnen. Diese Forschungz ielt darauf ab,K rankheiten wie Nierenbeckenentzündungeno hneE insatz vonA ntibiotika erfolgreichzutherapieren.Abstract: Ac entral aspect in chemistryi st he synthesiso f chemical compoundsinlaboratories, although theseprocessesa re oftent imec onsuming ande xpensive.T oday,u sing increasingly more powerful computersa nd continuously improved software anda lgorithms, it is possible to analyse moleculesn ot only in thel aboratory. Instead, properties, dynamics andreactions of moleculescan be predictedusing computationalm odelling.A sasubfield of chemistry, theoreticalc hemistry is constantly gainingi mportance. In this article, as imulatione xperimenti sp resented,w hich makes thes imulationo fm olecules accessible fors tudents at school anduniversitylevel.Asanexample,the computationalanalysisofmolecules is shown, whichprevent theadhesion of E. coli bacteria to humancells.Thisresearchaimsat treating inflammatory diseases of theu rogenitalt ract such as cystitiswithout theuse of antibiotics.Keywords: Computer simulations·theoreticalc hemistry · nature of science·adhesion of E. coli bacteria