title: Competition of a parathion-hydrolyzing Flavobacterium with bacteria from ditch water in carbon-, nitrate- and phosphate-limited continuous cultures.
abstract: Abstract The effect of competition for macroelements with bacteria from ditch water on the parathion-hydrolyzing Flavobacterium sp. ATCC 27551 (FB) was investigated within mixed continuous cultures under carbon-, nitrate- or phosphate-limited conditions. The high initial rate of parathion hydrolysis decreased rapidly in all cultures due to the loss of strain FB. Addition of 2-isopropyl-6-methyl-4-pyrimidinol (a selective source of carbon, nitrogen and energy for FB) to one nitrate- and carbon-limited chemostat caused a 20-fold increase in parathion-hydrolyzing activity compared to unamended control cultures and retention of FB. The presence of the parathion hydrolase-encoding gene could be demonstrated by a newly developed PCR detection method in all FB cultures during most of the cultivation period. These results suggest that competition effects cause the pesticide-degrading capacity of microbial communities depending on their frequency of exposure to the pesticide compounds.
authors.affiliation: Department of Environmental and Toxicological Chemistry (IBED-MTC), University of Amsterdam, Nieuwe Achtergracht 166, 1018 WS Amsterdam, The Netherlands.
authors.forename: Wander W
authors.initials: WW
authors.lastname: Sprenger
authors.forename: Annereinou
authors.initials: A
authors.lastname: Dijkstra
authors.forename: Gabriel J M
authors.initials: GJ
authors.lastname: Zwart
authors.forename: Miranda P
authors.initials: MP
authors.lastname: Agterveld
authors.forename: Paul C M
authors.initials: PC
authors.lastname: Noort
authors.forename: John R
authors.initials: JR
authors.lastname: Parsons