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

Flemming Ekelund; Søren Christensen; Regin Rønn; E. Buhl; C.S. Jacobsen

doi:10.1016/S0167-7012(99)00086-X

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

Flemming Ekelund, Søren Christensen, Regin Rønn, E. Buhl, C.S. Jacobsen

Terrestrial Ecology

8 Citations (Scopus)

Abstract

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 language	English
Journal	Journal of Microbiological Methods
Volume	38
Issue number	3
Pages (from-to)	177-182
ISSN	0167-7012
DOIs	https://doi.org/10.1016/S0167-7012(99)00086-X
Publication status	Published - 1999

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An automated technique for most-probable-number (MPN) analysis of densities of phagotrophic protists with lux-AB labelled bacteria as growth medium. / Ekelund, Flemming ; Christensen, Søren; Rønn, Regin et al.

In: Journal of Microbiological Methods, Vol. 38, No. 3, 1999, p. 177-182.

Research output: Contribution to journal › Journal article › Research › peer-review

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abstract = "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.",

author = "Flemming Ekelund and S{\o}ren Christensen and Regin R{\o}nn and E. Buhl and C.S. Jacobsen",

note = "Author Keywords: Heterotrophic flagellates; Lux AB labelled bacteria; Naked amoebae; Protozoa; Sediment; Soil",

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AU - Ekelund, Flemming

AU - Christensen, Søren

AU - Rønn, Regin

AU - Buhl, E.

AU - Jacobsen, C.S.

N1 - Author Keywords: Heterotrophic flagellates; Lux AB labelled bacteria; Naked amoebae; Protozoa; Sediment; Soil

PY - 1999

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N2 - 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.

AB - 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.

U2 - 10.1016/S0167-7012(99)00086-X

DO - 10.1016/S0167-7012(99)00086-X

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ER -

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

Abstract

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