Richardson-Gaudin mean-field for strong correlation in quantum chemistry.

Ground state eigenvectors of the reduced Bardeen-Cooper-Schrieffer Hamiltonian are employed as a wavefunction Ansatz to model strong electron correlation in quantum chemistry. This wavefunction is a product of weakly interacting pairs of electrons. While other geminal wavefunctions may only be employed in a projected Schrödinger equation, the present approach may be solved variationally with polynomial cost.

Effects of sterilization with hydrogen peroxide gas plasma, ethylene oxide, and steam on bioadhesive properties of nylon and polyethylene lines used for stabilization of canine stifle joints.

Objective: To compare effects of sterilization with hydrogen peroxide gas plasma (HPGP), ethylene oxide, and steam on bioadhesive properties of nylon and polyethylene lines used for stabilization of canine stifle joints.

Sample: Samples of a 36.3-kg test nylon leader line, 57.

Identification and mechanism of evolution of new alleles coding for the AIDA-I autotransporter of porcine pathogenic Escherichia coli.

Autotransporters are a large family of virulence factors of Gram-negative bacterial pathogens. The autotransporter adhesin involved in diffuse adherence (AIDA-I) is an outer membrane protein of Escherichia coli, which allows binding to epithelial cells as well as the autoaggregation of bacteria. AIDA-I is glycosylated by a specific heptosyltransferase encoded by the aah gene that forms an operon with the aidA gene.

A structural motif is the recognition site for a new family of bacterial protein O-glycosyltransferases.

The Escherichia coli Adhesin Involved in Diffuse Adherence (AIDA-I) is a multifunctional protein that belongs to the family of monomeric autotransporters. This adhesin can be glycosylated by the AIDA-associated heptosyltransferase (Aah). Glycosylation appears to be restricted to the extracellular domain of AIDA-I, which comprises imperfect repeats of a 19-amino-acid consensus sequence and is predicted to form a β-helix.

In vitro assay of bacterial adhesion onto mammalian epithelial cells.

To cause infections, bacteria must colonize their host. Bacterial pathogens express various molecules or structures able to promote attachment to host cells(1). These adhesins rely on interactions with host cell surface receptors or soluble proteins acting as a bridge between bacteria and host.

Growth-phase-dependent expression of the operon coding for the glycosylated autotransporter adhesin AIDA-I of pathogenic Escherichia coli.

The adhesin involved in diffuse adherence (AIDA-I) is an autotransporter found in pathogenic strains of Escherichia coli causing diarrhea in humans and pigs. The AIDA-I protein is glycosylated by a specific enzyme, the AIDA-associated heptosyltransferase (Aah). The aah gene is immediately upstream of the aidA gene, suggesting that they form an operon.

Molecular composition of staufen2-containing ribonucleoproteins in embryonic rat brain.

Messenger ribonucleoprotein particles (mRNPs) are used to transport mRNAs along neuronal dendrites to their site of translation. Numerous mRNA-binding and regulatory proteins within mRNPs finely regulate the fate of bound-mRNAs. Their specific combination defines different types of mRNPs that in turn are related to specific synaptic functions.

Conformation change in a self-recognizing autotransporter modulates bacterial cell-cell interaction.

Bacteria mostly live as multicellular communities, although they are unicellular organisms, yet the mechanisms that tie individual bacteria together are often poorly understood. The adhesin involved in diffuse adherence (AIDA-I) is an adhesin of diarrheagenic Escherichia coli strains. AIDA-I also mediates bacterial auto-aggregation and biofilm formation and thus could be important for the organization of communities of pathogens.

Escherichia coli STb toxin binding to sulfatide and its inhibition by carragenan.

Escherichia coli heat-STb is an important cause of diarrhea in piglets. STb was shown to interact specifically with sulfatide (3'-sulfogalactosyl-ceramide) present on the surface of epithelial cells of piglet jejunum. Basic data are lacking on STb binding to sulfatide in solution and more precisely on the possible inhibition of this interaction.

O-linked glycosylation ensures the normal conformation of the autotransporter adhesin involved in diffuse adherence.

The Escherichia coli adhesin involved in diffuse adherence (AIDA-I) is one of the few glycosylated proteins found in Escherichia coli. Glycosylation is mediated by a specific heptosyltransferase encoded by the aah gene, but little is known about the role of this modification and the mechanism involved. In this study, we identified several peptides of AIDA-I modified by the addition of heptoses by use of mass spectrometry and N-terminal sequencing of proteolytic fragments of AIDA-I.

Mutations affecting the biogenesis of the AIDA-I autotransporter.

Autotransporters are simple systems that Gram-negative bacteria employ to secrete proteins to their surfaces or into the extracellular milieu. They consist of an N-terminal passenger domain and a C-terminal domain that is thought to insert into the outer membrane and mediate the secretion of the passenger domain. Despite the apparent simplicity of these secretion systems, their mechanism of translocation is still not completely understood.

Contribution of AIDA-I to the pathogenicity of a porcine diarrheagenic Escherichia coli and to intestinal colonization through biofilm formation in pigs.

In order to evaluate the role of the AIDA-I of porcine diarrheagenic Escherichia coli strain PD20 serogroup O143 (AIDA-I(+), STb(+)), a mutant strain PD20M (AIDA-I(-), STb(+)) was generated from strain PD20 by an allelic exchange procedure. In addition, the full-length aidA gene was reintroduced into strain PD20M to generate the complemented strain PD20C (pTaidA, AIDA-I(+), STb(+)). A non-pathogenic E.

Proteolytic processing is not essential for multiple functions of the Escherichia coli autotransporter adhesin involved in diffuse adherence (AIDA-I).

The Escherichia coli adhesin involved in diffuse adherence (AIDA-I), like many other autotransporter proteins, is released in the periplasm as a proprotein undergoing proteolytic processing after its translocation across the outer membrane. The proprotein is cleaved into a membrane-embedded fragment, AIDAc, and an extracellular fragment, the mature AIDA-I adhesin. The latter remains noncovalently associated with the outer membrane and can be released by heat treatment.

The periplasmic folding of a cysteineless autotransporter passenger domain interferes with its outer membrane translocation.

Autotransporters are single polypeptides consisting of an outer membrane translocation domain mediating the translocation of a passenger domain. The periplasmic folding state of the passenger domain is controversial. By comparisons of passenger domains differing in their folding properties, our results suggest that periplasmic folding of passenger domains interferes with translocation.

Waterborne pathogen detection by use of oligonucleotide-based microarrays.

A small-oligonucleotide microarray prototype was designed with probes specific for the universal 16S rRNA and cpn60 genes of several pathogens that are usually encountered in wastewaters. In addition to these two targets, wecE-specific oligonucleotide probes were included in the microarray to enhance its discriminating power within the Enterobacteriaceae family. Universal PCR primers were used to amplify variable regions of 16S rRNA, cpn60, and wecE genes directly in Escherichia coli and Salmonella enterica serovar Typhimurium genomic DNA mixtures (binary); E.

Influence of L-leucine and L-alanine on Lrp regulation of foo, coding for F1651, a Pap homologue.

The foo operon encodes F165 1 fimbriae that belong to the P-regulatory family and are synthesized by septicemic Escherichia coli. Using an Lrp-deficient host and the lrp gene cloned under the arabinose pBAD promoter, we demonstrated that foo was transcribed proportionally to the amount of Lrp synthesized. L-leucine and L-alanine decreased drastically the steady-state transcription of foo and modified phase variation, independently of the presence of FooI.