In the plant pathogenic bacterium, Pseudomonas syringae, the exopolysaccharide levan is synthesized by extracellular levansucrase (Lsc), which is encoded by two conserved 1,296-bp genes termed lscB and lscC in P. syringae strain PG4180. A third gene, lscA, is homologous to the 1,248-bp lsc gene of the bacterium Erwinia amylovora, causing fire blight. However, lscA is not expressed in P. syringa...

Capsule (cps) gene expression in Escherichia coli is controlled by a complex network of regulators. Transcription of the cps operon is controlled by at least two positive regulators, RcsA and RcsB. We show here that RcsA functions to activate its own expression, as seen by the 100-fold-increased expression of a rcsA::lacZ transcriptional fusion in strains with high levels of RcsA protein, eithe...

Erwinia amylovora causes fire blight on several plant species such as apple and pear, which produce diverse phytoalexins as defence mechanisms. An evolutionary successful pathogen thus must develop resistance mechanisms towards these toxic compounds. The E. amylovora outer membrane protein, TolC, might mediate phytoalexin resistance through its interaction with the multidrug efflux pump, AcrAB....

background and objectives: we developed and evaluated the utility of a quadruplex taqman real-time pcr assay that allows simultaneous identification of vancomycin-resistant genotypes and clinically relevant enterococci. materials and methods: the specificity of the assay was tested using reference strains of vancomycin-resistant and susceptible enterococci. in total, 193 clinical isolates were ...

Pantoea agglomerans E325, the active ingredient in a commercial product for fire blight control, was previously shown in vitro to produce a unique alkaline- and phosphate-sensitive antibiotic specific to Erwinia amylovora. Antibiosis was evaluated as a mode of antagonism on flower stigmas using two antibiosis-deficient mutants. On King's medium B, mutants E325ad1 and E325ad2 have stable smooth-...

aim : the purpose of this study was to investigate the prevalence of enteropathogenic escherichia coli (epec) and shiga toxin producing e. coli (stec) strains in healthy broilers in iran.   background : stec and epec strains as diarrheagenic e. coli are among the most prevalent causative agents in acute diarrhea. domestic animals, mainly cattle and sheep, have been implicated as the principal r...

Background Many Escherichia coli strains are considered to be a component of the normal flora found in the human and animal intestinal tracts. While most E. coli strains are commensal, some strains encode virulence factors that enable the bacteria to cause intestinal and extra-intestinal clinically-relevant infections. Colibactin, encoded by a genomic island (pks island), and cytotoxic necrotiz...

Hfq is a global small RNA (sRNA) chaperone that interacts with Hfq-regulated sRNAs and functions in the posttranscriptional regulation of gene expression. In this work, we identified Hfq to be a virulence regulator in the Gram-negative fire blight pathogen Erwinia amylovora. Deletion of hfq in E. amylovora Ea1189 significantly reduced bacterial virulence in both immature pear fruits and apple s...

Sucrose is an important storage and transport sugar of plants and an energy source for many phytopathogenic bacteria. To analyze regulation and biochemistry of sucrose metabolism of the fire blight pathogen Erwinia amylovora, a chromosomal fragment which enabled Escherichia coli to utilize sucrose as sole carbon source was cloned. By transposon mutagenesis, the scr regulon of E. amylovora was t...