It was investigated in humans whether the incorporation of an extinction cue attenuates renewal of extinguished conditioned performance using a computerized task. All participants received an acquisition phase against a specific background, context A. In this context they learned that two conditioned stimuli, CS1 and CS2, predicted the occurrence of an aversive unconditioned stimulus (US) and t...

The structure of the new protonic conductor, b-Cs3(HSO4)2 (H22x(P12x , Sx)O4) (with a superprotonic transition at 125°C), has been determined by single-crystal X-ray diffraction methods. Structural features of this and the related compound, aCs3(HSO4)2(H2PO4), have been further examined by Raman and IR spectroscopy. The new compound crystallizes in space group C2/c, contains four formula units ...

The genetic relatedness among 29 enterotoxigenic Escherichia coli strains of serotype O6:H16 was investigated by randomly amplified polymorphic DNA (RAPD) analysis. The strains were isolated in different parts of the world, displayed CS1-CS3 or CS2-CS3 profiles, and expressed heat-labile toxin (LT) and heat-stable toxin; a single strain expressed only LT. Ten RAPD types were distinguished and s...

Moraxella bovis, the causative agent of infectious bovine keratoconjunctivitis, exhibits several virulence factors, including pili, haemolysin, leukotoxin, and proteases. The pili are filamentous appendages which mediate bacterial adherence. Prior studies have shown that Q-piliated M. bovis Epp63 are more infectious and more pathogenic than I-piliated and non-piliated isogenic variants, suggest...

Geobacter sulfurreducens required expression of electrically conductive pili to form biofilms on Fe(III) oxide surfaces, but pili were also essential for biofilm development on plain glass when fumarate was the sole electron acceptor. Furthermore, pili were needed for cell aggregation in agglutination studies. These results suggest that the pili of G. sulfurreducens also have a structural role ...

Chromosomal genes encoding the MS and Gal-Gal binding properties have been cloned into separate recombinants and their respective pili characterized. Hapten inhibition of hemagglutination with synthetic carbohydrate receptor analogues and carbohydrate-adsorbed latex agglutination studies indicate that Gal-Gal and MS pili collectively exhibit the binding properties of the parent strain. MS pili ...

Pili have been shown to contribute to the virulence of different Gram-positive pathogenic species. Among other critical steps of bacterial pathogenesis, these structures participate in adherence to host cells, colonization and systemic virulence. Recently, the presence of at least four discrete gene clusters encoding putative pili has been revealed in the major swine pathogen and emerging zoono...

The opportunistic pathogen Pseudomonas aeruginosa produces multifunctional, polar, filamentous appendages termed type IV pili. Type IV pili are involved in colonization during infection, twitching motility, biofilm formation, bacteriophage infection, and natural transformation. Electrostatic surface analysis of modeled pilus fibers generated from P. aeruginosa strain PAK, K122-4, and KB-7 pilin...

Telomerase contains an essential RNA, which includes the template sequence copied by the reverse transcription action of telomerase into telomeric DNA. Using phylogenetic comparison, we identified seven conserved sequences in telomerase RNAs from Kluyveromyces budding yeasts. We show that two of these sequences, CS3 and CS4, are essential for normal telomerase function and can base-pair to form...

Pili separated from the cells of Corynebacterium renale strain 46 (type II) by agitation at high speed in a homogenizer were purified by repeated cycles of ammonium sulfate precipitation, sonic treatment, and centrifugation. The preparation of purified pili formed a single antigen-antibody line in agar gel and showed an absorption maximum at 275 nm. The pili subjected to dodecyl sulfate-polyacr...