A novel method for the isolation of motile bacteria using gradient culture systems.
Isolation of motile bacteria from stream water samples was achieved by using Lutrol F127 (poloxamer 407) as a gelling agent in culture media. This block copolymer has the property of repeatedly liquefying and solidifying at low and high temperatures, respectively. The ability of motile bacteria to move through liquid-state Lutrol F127 towards a higher nutrient concentration was exploited. After establishment of the nutrient gradient and inoculation, the system was cooled to liquefy the medium and kept liquid to allow motile bacteria to move. Raising the temperature allowed solidification and prevented further movement. Colonies could be easily removed. The proportion of motile isolates (determined by microscopic observation) increased from 42% in the indigenous population to 100% after isolation using the gradient system.
Thomson
R
R
Hatherly Laboratories, School of Biological Sciences, University of Exeter, EX4 4PS, Exeter, UK.
Pickup
R
R
Porter
J
J
D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry; D005618:Fresh Water / Q000382:microbiology; D020442:Poloxamer
D003470:Culture Media; D020442:Poloxamer