title: Model system for studies of microbial dynamics at exuding surfaces such as the rhizosphere.
abstract: An autoclavable all-glass system for studying microbial dynamics at permeable surfaces is described.  Standard hydrophobic or hydrophilic membranes (46-mm diameter) of various pore sizes were supported on a glass frit through which nutrient solutions were pumped by a peristaltic pump.  The pump provided a precisely controlled flow at speeds of 0.5 to 500 ml of defined or natural cell exudates per h, which passed through the membrane into a receiving vessel.  The construction allowed a choice of membranes, which could be modified.  The system was tested with a bacterium, isolated from rape plant roots (Brassica napus L.), that was inoculated on a hydrophilic membrane filter and allowed to develop into a biofilm.  A defined medium with a composition resembling that of natural rape root exudate was pumped through the membrane at 0.5 ml/h.  Scanning electron microscopic examinations indicated that the inoculum formed microcolonies embedded in exopolymers evenly distributed over the membrane surface.  The lipid composition and content of poly-beta-hydroxybutyrate in free-living and adhered cells were determined by gas chromatography.  The bacterial consumption of amino acids in the exudate was also studied.
authors.affiliation: Laboratory of Ecological Chemistry, Lund University, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Odham
authors.forename: A
authors.initials: A
authors.lastname: Tunlid
authors.forename: A
authors.initials: A
authors.lastname: Valeur
authors.forename: P
authors.initials: P
authors.lastname: Sundin
authors.forename: D C
authors.initials: DC
authors.lastname: White
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000378:metabolism; D018441:Biofilms; D018533:Biomass; D001937:Brassica / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D004783:Environmental Microbiology; D004867:Equipment Design; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D005374:Filtration / Q000295:instrumentation; D006090:Gram-Negative Bacteria / Q000378:metabolism* / Q000648:ultrastructure; D006885:Hydroxybutyrates / Q000032:analysis / Q000378:metabolism*; D008854:Microscopy, Electron; D010743:Phospholipids / Q000032:analysis / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D011091:Polyesters / Q000032:analysis / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D000596:Amino Acids; D005227:Fatty Acids; D006885:Hydroxybutyrates; D010743:Phospholipids; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates