The pelB gene encodes pectate lyase B, one of three pectate lyases identified in Erwinia carotovora EC. Pectate lyase B was purified from Escherichia coli containing the pelB gene on a recombinant plasmid. The activity of the protein was optimal at a pH of 8.3. The amino acid composition, N-terminal amino acid sequence, and C-terminal peptide sequence were determined and compared with the polyp...

Genomes of Salmonella enterica isolates, including those linked to outbreaks of produce-associated gastroenteritis, contain sdiA, which encodes a receptor of N-acyl homoserine lactones (AHL). AHL are the quorum-sensing signals used by bacteria to coordinately regulate gene expression within -their populations. Because S. enterica does not produce its own AHL, SdiA is hypothesized to function in...

In a previous study, pnlA (the DNA damage-inducible structural gene for pectin lyase) of Erwinia carotovora subsp. carotovora 71 was localized to a 1.4-kb DNA segment within a 3.4-kb EcoRI fragment (J. L. McEvoy, H. Murata, and A. K. Chatterjee, J. Bacteriol. 172:3284-3289, 1990). We present here DNA sequence data for a 2.2-kb region revealing an open reading frame of 870 bases, corresponding t...

N-acyl L-homoserine lactones (AHLs) constitute a predominant class of quorum-sensing signaling molecules used by Gram-negative bacteria. Here, we report a sensitive and non-targeted HPLC-MS/MS method based on parallel reaction monitoring (PRM) to identify and quantitate known, unanticipated, and novel AHLs in microbial samples. Using a hybrid quadrupole-high resolution mass analyzer, this metho...

The polygalacturonase, clearly differentiated from polygalacturonic acid trans-eliminase, produced in the culture fluid of Erwinia carotovora was purified 56-fold by means of acetone precipitation, acetate butfer extraction, and two successive treatments by chromatography on carboxymethyl cellulose. The purified enzyme is specific for nonmethoxylated polygalacturonic acid. It shows an optimum p...

Phytopathogenic strains of Burkholderia cepacia (synonym Pseudomonas cepacia) produce endopolygalacturonase, whereas strains of clinical and soil origin do not. Growth of a phytopathogenic strain (ATCC25416) at elevated temperatures resulted in nonpectolytic derivatives that were either cured of a resident plasmid or contained a plasmid of reduced mass. The resident 200-kb plasmid (pPEC320) in ...

When ingested, pectin can lower serum cholesterol levels in humans. Pectin is degraded by fecal bacteria in the colon. We examined the release of methanol (MeOH) by this degradation. A 0.2% glucose (2 g/L) mixture was used as the control medium. A pure culture of pectinolytic Erwinia carotovora was the control bacterium. The chief substrates were, in set 1, 0.2% pectin (2 g/L) and, in set 2, 0....