title: A novel directly coupled gradostat.
abstract: The original bidirectional compound chemostat (gradostat) described by Lovitt and Wimpenny has been simplified by making a more compact apparatus in which chemical gradients are established by diffusion between adjacent culture chambers.  The experimental model (diffusion coupled (DC) gradostat) consisted of five chambers whose contents could be agitated by turbines rotating in the horizontal plane on a common shaft.  Two biological experiments were designed to reveal the value of the DC gradostat.  A methylotroph (Methylophilus methylotrophus) grown in a methanol gradient showed expected changes in cell viability as a function of position in the five vessel array.  Cells of two species of photosynthetic bacteria (Rhodobacter capsulata and Rhodopseudomonas marina/agilis) with different salt sensitivities could be mixed and subsequently separated by the DC gradostat operating with a NaCl gradient of 0-3% w/v.
authors.affiliation: Department of Pure and Applied Biology, University of Wales, College of Cardiff, UK.
authors.forename: J W
authors.initials: JW
authors.lastname: Wimpenny
authors.forename: R G
authors.initials: RG
authors.lastname: Earnshaw
authors.forename: H
authors.initials: H
authors.lastname: Gest
authors.forename: J M
authors.initials: JM
authors.lastname: Hayes
authors.forename: J L
authors.initials: JL
authors.lastname: Favinger
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000254:growth & development*; D001420:Bacteria, Aerobic / Q000187:drug effects / Q000254:growth & development*; D001431:Bacteriological Techniques / Q000295:instrumentation*; D003470:Culture Media; D015194:Diffusion Chambers, Culture; D004783:Environmental Microbiology; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D000432:Methanol / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D003470:Culture Media; D012965:Sodium Chloride; D000432:Methanol