Refinement of a therapeutic Shiga toxin-binding probiotic for human trials.

We have previously constructed a recombinant bacterium expressing a modified lipopolysaccharide (LPS) mimicking the Shiga toxin receptor, which binds toxin with high avidity. This involved cloning Neisseria galactosyl transferase genes (lgtC and lgtE) in pK184 in a derivative of Escherichia coli R1 (CWG308). Such constructs have considerable potential for prevention of disease caused by Shiga toxin-producing E.

Phylogeny and evolution of basils and allies (Ocimeae, Labiatae) based on three plastid DNA regions.

A phylogeny of basils and allies (Lamiaceae, tribe Ocimeae) based on sequences of the trnL intron, trnL-trnF intergene spacer and rps 16 intron of the plastid genome is presented. Several methods were used to reconstruct phylogenies and to assess statistical support for clades: maximum parsimony with equally and successively weighted characters, bootstrap resampling, and Bayesian inference. The phylogeny is used to investigate the distribution of morphological, pericarp anatomy, chemical, and pollen characters as well as the geographical distribution of the clades.

Enhanced CXC chemokine responses of human colonic epithelial cells to locus of enterocyte effacement-negative shiga-toxigenic Escherichia coli.

There is increasing evidence that by facilitating translocation of Shiga toxin (Stx) across the intestinal epithelium and by transporting bound toxin to remote sites such as the renal endothelium, polymorphonuclear leukocytes (PMNs) play a key role in the pathogenesis of Shiga-toxigenic Escherichia coli (STEC) disease. Plasma levels of PMN-attracting CXC chemokines such as interleukin-8 (IL-8) also appear to correlate in humans with the severity of disease. Thus, the capacity of STEC strains to elicit CXC chemokine responses in intestinal epithelial cells may be a crucial step in pathogenesis.

The chemotaxonomic significance of two bioactive caffeic acid esters, nepetoidins A and B, in the Lamiaceae.

A survey of leaf surface constituents in the family Lamiaceae using HPLC with diode array detection revealed the presence of two characteristic phenolic compounds in many species. The distribution of these phenolics in the Lamiaceae was found to be of taxonomic significance, as they were present in the great majority of species investigated for the subfamily Nepetoideae, including representatives of the well-known genera of culinary herbs, mint, rosemary, sage, thyme and basil. In contrast, they were absent from species of the other subfamilies of Lamiaceae studied and from the related families Verbenaceae, Scrophulariaceae, Acanthaceae and Buddlejaceae.

Chemical profiling of Ocimum americanum using external flavonoids.

A HPLC survey was undertaken of the external flavonoids in 111 herbarium specimens of Ocimum americanum L. (O. canum Sims), which were largely collected from their natural habitats throughout Africa and Asia.

Mutation of luxS of Streptococcus pneumoniae affects virulence in a mouse model.

The LuxS protein is required for the biosynthesis of the type 2 autoinducer (AI-2), which is involved in quorum sensing in a wide range of bacterial species. We have determined the effects of a defined luxS mutation on the virulence of Streptococcus pneumoniae. Although the luxS mutant displayed reduced virulence relative to its wild-type parent, the type 2 strain D39, it was by no means avirulent in a mouse model.

Distribution of the saa gene in strains of Shiga toxin-producing Escherichia coli of human and bovine origins.

Certain strains of Shiga toxin-producing Escherichia coli (STEC) which do not have the locus of enterocyte effacement pathogenicity island carry the STEC autoagglutinating adhesin (saa) gene. The distribution of the saa gene in STEC isolates from patients with hemolytic-uremic syndrome (HUS), patients with less severe diarrheal disease, asymptomatic individuals, and healthy cattle was examined. saa-positive strains were detected more frequently (P < 0.

Association between presenilin-1 Glu318Gly mutation and familial Alzheimer's disease in the Australian population.

Mutations in the presenilin-1 (PS-1) gene on chromosome 14 account for the majority of early-onset familial Alzheimer's disease (FAD) cases. To date, more than 90 mutations have been identified and, while most of these mutations are completely penetrant, the Glu318Gly mutation has been suggested to be partially penetrant. These findings indicate that it may play a similar role to apolipoprotein E (APOE)-epsilon4 by acting as a genetic risk factor for AD.

APOE-epsilon4 and APOE -491A polymorphisms in individuals with subjective memory loss.

The accurate clinical diagnosis of Alzheimer's disease can only be made with a high degree of certainty in specialized centres. The identification of predictive or diagnostic genetic factors may improve accuracy of disease prediction or diagnosis. One major genetic risk factor, the epsilon4 allele of the apolipoprotein E gene, is universally recognised.

Scutellarein 4'-methyl ether glycosides as taxonomic markers in Teucridium and Tripora (Lamiaceae, Ajugoideae).

The flavonoid profiles of two monotypic genera, Teucridium and Tripora, have been studied by analytical methods. These genera were formerly placed in the Verbenaceae, but are now classified in the Lamiaceae, subfamily Ajugoideae. The major flavonoids of both genera were identified as glycosides of scutellarein 4'-methyl ether (5,6,7-trihydroxy-4'methoxyflavone) and acacetin (5,7-dihydroxy-4'-methoxyflavone).

Characterization of a novel type IV pilus locus encoded on the large plasmid of locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli strains that are virulent for humans.

The majority of Shiga-toxigenic Escherichia coli (STEC) strains isolated from humans with gastrointestinal disease carry large (approximately 90-kb) plasmids. We have been analyzing the megaplasmid (designated pO113) from an O113:H21 STEC strain (98NK2). This strain lacks the locus for enterocyte effacement (LEE) and yet was responsible for an outbreak of hemolytic uremic syndrome.

Reactivity of convalescent-phase hemolytic-uremic syndrome patient sera with the megaplasmid-encoded TagA protein of Shiga toxigenic Escherichia coli O157.

A cosmid library of Shiga toxigenic Escherichia coli (STEC) O157:H7 strain EDL933 DNA was screened for clones capable of reacting with convalescent-phase serum from a patient with hemolytic-uremic syndrome (HUS), in an attempt to identify candidate virulence genes. One of the immunoreactive clones contained a portion of the large plasmid pO157, and the immunoreactive gene product was identified as TagA. The function of this 898-amino-acid protein is unknown, but it exhibits 42% amino acid sequence identity and 63% similarity to a 312-amino-acid region of a ToxR-regulated lipoprotein of Vibrio cholerae.

Direct detection and characterization of Shiga toxigenic Escherichia coli by multiplex PCR for stx1, stx2, eae, ehxA, and saa.

We recently described a novel megaplasmid-encoded adhesin produced by certain Shiga toxigenic Escherichia coli (STEC) strains that lack the locus for enterocyte effacement (LEE) pathogenicity island. This adhesin, designated Saa (STEC autoagglutinating adhesin), may be a marker for a subset of LEE-negative STEC strains capable of causing severe gastrointestinal and systemic diseases in humans. In this study, we developed a pentavalent PCR assay for the detection of saa as well as other proven and putative STEC virulence genes (stx1, stx2, eae, and ehxA).

Association between the presenilin-1 mutation Glu318Gly and complaints of memory impairment.

Presenilin-1 mutations account for nearly 50% of all early-onset familial cases of Alzheimer's disease. Most of these mutations are completely penetrant, although the recently described Glu318Gly substitution seems to have only partial penetrance. These findings suggest that the Glu318Gly mutation may work as a genetic risk factor for Alzheimer's disease.

Characterization of Saa, a novel autoagglutinating adhesin produced by locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli strains that are virulent for humans.

The capacity of Shiga toxigenic Escherichia coli (STEC) to adhere to the intestinal mucosa undoubtedly contributes to pathogenesis of human disease. The majority of STEC strains isolated from severe cases produce attaching and effacing lesions on the intestinal mucosa, a property mediated by the locus of enterocyte effacement (LEE) pathogenicity island. This element is not essential for pathogenesis, as some cases of severe disease, including hemolytic uremic syndrome (HUS), are caused by LEE-negative STEC strains, but the mechanism whereby these adhere to the intestinal mucosa is not understood.

Clinical characteristics of individuals with subjective memory loss in Western Australia: results from a cross-sectional survey.

Subjective memory complaint is common in later life. Its relationship to future risk of dementia is unclear, although many reports have found a positive association. We designed the present cross-sectional survey to investigate the clinical features associated with subjective memory impairment.

Neutralization of Shiga toxins Stx1, Stx2c, and Stx2e by recombinant bacteria expressing mimics of globotriose and globotetraose.

Strains of Escherichia coli producing Shiga toxins Stx1, Stx2, Stx2c, and Stx2d cause gastrointestinal disease and the hemolytic-uremic syndrome in humans. We have recently constructed a recombinant bacterium which displays globotriose (the receptor for these toxins) on its surface and adsorbs and neutralizes these Shiga toxins with very high efficiency. This agent has great potential for the treatment of humans with such infections.

Oral administration of formaldehyde-killed recombinant bacteria expressing a mimic of the Shiga toxin receptor protects mice from fatal challenge with Shiga-toxigenic Escherichia coli.

Gastrointestinal disease caused by Shiga toxin-producing Escherichia coli (STEC) is frequently complicated by life-threatening toxin-induced systemic sequelae, including the hemolytic uremic syndrome. We previously constructed a recombinant bacterium displaying a Shiga toxin receptor mimic on its surface which neutralized Shiga toxins with very high efficiency. Moreover, oral administration of the live bacterium completely protected mice from challenge with virulent STEC.

Genetic diversity of Ocimum gratissimum L. based on volatile oil constituents, flavonoids and RAPD markers.

Morphological, chemical and genetic differences of 12 tree basil (Ocimum gratissimum L.) accessions were studied to determine whether volatile oils and flavonoids can be used as taxonomical markers and to examine the relationship between RAPDs to these chemical markers. Eugenol, thymol, and geraniol were the major volatile oil constituents found in Ocimum gratissimum.

Up-regulation of both intimin and eae-independent adherence of shiga toxigenic Escherichia coli O157 by ler and phenotypic impact of a naturally occurring ler mutation.

Shiga toxigenic Escherichia coli (STEC) strains are important human pathogens which are capable of causing diarrhea, hemorrhagic colitis, and the potentially fatal hemolytic-uremic syndrome (HUS). An important virulence trait of certain STEC strains, such as those belonging to serogroup O157, is the capacity to produce attaching and effacing (A/E) lesions on enterocytes, a property encoded by the locus for enterocyte effacement (LEE). LEE contains the eae gene, which encodes intimin, an outer membrane protein which mediates the intimate attachment of bacteria to the host epithelial cell surface, and eae is routinely used as a marker for LEE-positive STEC strains.