An automated technique for most-probable-number (MPN) analysis of densities of phagotrophic protists with lux-AB labelled bacteria as growth medium

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An automated modification of the most-probable-number (MPN) technique has been developed for enumeration of phagotrophic protozoa. The method is based on detection of prey depletion in micro titre plates rather than on presence of protozoa. A transconjugant Pseudomonas fluorescens DR54 labelled with a luxAB gene cassette was constructed, and used as growth medium for the protozoa in the micro titre plates. The transconjugant produced high amounts of luciferase which was stable and allowed detection for at least 8 weeks. Dilution series of protozoan cultures and soil suspensions were inoculated into micro titre plates amended with a suspension of the transconjugant. After 45 days measurement of light emission allowed detection of individual wells in the titre plates, where protozoan grazing had removed the inoculated bacteria.
Original languageEnglish
JournalJournal of Microbiological Methods
Issue number3
Pages (from-to)177-182
Publication statusPublished - 1999

Bibliographical note

Author Keywords: Heterotrophic flagellates; Lux AB labelled bacteria; Naked amoebae; Protozoa; Sediment; Soil

ID: 4625146