title: Maltose and maltodextrin utilization by Listeria monocytogenes depend on an inducible ABC transporter which is repressed by glucose.
abstract: BACKGROUND
  In the environment as well as in the vertebrate intestine, Listeriae have access to complex carbohydrates like maltodextrins. Bacterial exploitation of such compounds requires specific uptake and utilization systems.
  
  
  RESULTS
  We could show that Listeria monocytogenes and other Listeria species contain genes/gene products with high homology to the maltodextrin ABC transporter and utilization system of B. subtilis. Mutant construction and growth tests revealed that the L. monocytogenes gene cluster was required for the efficient utilization of maltodextrins as well as maltose. The gene for the ATP binding protein of the transporter was located distant from the cluster. Transcription analyses demonstrated that the system was induced by maltose/maltodextrins and repressed by glucose. Its induction was dependent on a LacI type transcriptional regulator. Repression by glucose was independent of the catabolite control protein CcpA, but was relieved in a mutant defective for Hpr kinase/phosphorylase.
  
  
  CONCLUSIONS
  The data obtained show that in L. monocytogenes the uptake of maltodextrin and, in contrast to B. subtilis, also maltose is exclusively mediated by an ABC transporter. Furthermore, the results suggest that glucose repression of the uptake system possibly is by inducer exclusion, a mechanism not described so far in this organism.
authors.affiliation: Department of Studies in Microbiology, University of Mysore, Mysore, India. sguom@yahoo.com
authors.forename: Shubha
authors.initials: S
authors.lastname: Gopal
authors.forename: Daniela
authors.initials: D
authors.lastname: Berg
authors.forename: Nicole
authors.initials: N
authors.lastname: Hagen
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Schriefer
authors.forename: Regina
authors.initials: R
authors.lastname: Stoll
authors.forename: Werner
authors.initials: W
authors.lastname: Goebel
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kreft
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D001412:Bacillus subtilis / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000378:metabolism*; D008320:Maltose / Q000378:metabolism*; D005810:Multigene Family; D011134:Polysaccharides / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D018528:ATP-Binding Cassette Transporters; D011134:Polysaccharides; D008320:Maltose; C008315:maltodextrin; D005947:Glucose