Cronobacter Support
05-19-2009, 03:10 PM
1st International Conference on Cronobacter Poster Abstract 45
Alpha glucosidase activity and yellow pigmentation in Cronobacter spp. and recently described new Enterobacter spp.
Recently, three novel Enterobacter species (Enterobacter helveticus, Enterobacter turicensis, Enterobacter pulveris), exploiting the same niche as Cronobacter spp. (IFM, production environment), have been described. By employing the currently available cultural detection methods for Cronobacter spp., theses species may lead to false positive results, due to their alpha glucosidase activity and the yellow pigment production. The aim of this project is to characterize both features on the genetic level, not having sequenced genomes for these new species. Bacterial Artificial Chromosome (BAC) libraries were constructed for the type strains of the newly described Enterobacter spp. Screening of transformants for alpha-glucosidase activity was performed in microplates containing LB broth supplemented with 4-methylumbelliferyl-a-D-glucoside. The pigment expression of the E. coli transformants was assessed on LB agar after 48 hrs of exposition to natural light at room temperature. Screening for alpha-glucosidase activity resulted in 5 (E. helveticus), one (E. pulveris) and one (E. turicensis) positive transformants. Individual library testing for pigmentation revealed 3 (E. helveticus), 10 (E. turicensis) and 6 (E. pulveris ) candidates. So far, sequencing of two candidate clone inserts - BAC3B1 (alpha-glucosidase) and BAC20A1 (yellow pigmentation) both originating from the E. helveticus library has been completed and the annotation is currently ongoing. Sequencing and annotation of the remaining 4 BAC clones (from 2 libraries) is work in progress. Sequence comparisons among these novel Enterobacter spp. and relative to the Cronobacter spp. will be performed in order to design a multiplex PCR approach enabling a clear discrimination between these organisms in the infant formula production line.
Britta Stoop1, Roger Stephan1, Thomas Rattei2 and Angelika Lehner1
1 Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, CH-8057, Zürich, Switzerland. 2Genome Oriented Bioinformatics, Technical University Munich, Freising, Germany.
Alpha glucosidase activity and yellow pigmentation in Cronobacter spp. and recently described new Enterobacter spp.
Recently, three novel Enterobacter species (Enterobacter helveticus, Enterobacter turicensis, Enterobacter pulveris), exploiting the same niche as Cronobacter spp. (IFM, production environment), have been described. By employing the currently available cultural detection methods for Cronobacter spp., theses species may lead to false positive results, due to their alpha glucosidase activity and the yellow pigment production. The aim of this project is to characterize both features on the genetic level, not having sequenced genomes for these new species. Bacterial Artificial Chromosome (BAC) libraries were constructed for the type strains of the newly described Enterobacter spp. Screening of transformants for alpha-glucosidase activity was performed in microplates containing LB broth supplemented with 4-methylumbelliferyl-a-D-glucoside. The pigment expression of the E. coli transformants was assessed on LB agar after 48 hrs of exposition to natural light at room temperature. Screening for alpha-glucosidase activity resulted in 5 (E. helveticus), one (E. pulveris) and one (E. turicensis) positive transformants. Individual library testing for pigmentation revealed 3 (E. helveticus), 10 (E. turicensis) and 6 (E. pulveris ) candidates. So far, sequencing of two candidate clone inserts - BAC3B1 (alpha-glucosidase) and BAC20A1 (yellow pigmentation) both originating from the E. helveticus library has been completed and the annotation is currently ongoing. Sequencing and annotation of the remaining 4 BAC clones (from 2 libraries) is work in progress. Sequence comparisons among these novel Enterobacter spp. and relative to the Cronobacter spp. will be performed in order to design a multiplex PCR approach enabling a clear discrimination between these organisms in the infant formula production line.
Britta Stoop1, Roger Stephan1, Thomas Rattei2 and Angelika Lehner1
1 Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, CH-8057, Zürich, Switzerland. 2Genome Oriented Bioinformatics, Technical University Munich, Freising, Germany.