of the Ruminal Bacterium Synergistes jonesii in a Mixed-Population ...

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Mar 7, 1993 - ... College of Veterinary Medicine,University ofIllinois, Urbana, Illinois 61801 ..... Stahl, D. A., B. Flesher, H. R. Mansfield, and L. Montgomery.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, May 1993, p. 1607-1612

0099-2240/93/051607-06$02.00/0 Copyright ©) 1993, American Society for Microbiology

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Vol. 59, No. 5

Development of an Oligonucleotide Probe Targeting 16S rRNA and Its Application for Detection and Quantitation of the Ruminal Bacterium Synergistes jonesii in a Mixed-Population Chemostat CHRISTOPHER S. McSWEENEY,l* RODERICK I. MACKIE,2 AGNES A. ODENYO,2 AND DAVID A. STAHL3 Long Pocket Laboratories, CSIRO Division of Tropical Animal Production, Private Bag No. 3 P 0, Indooroopilly, Queensland 4068, Australia,' and Department ofAnimal Sciences2 and Department of Veterinary Pathobiology,3 College of Veterinary Medicine, University of Illinois, Urbana, Illinois 61801 Received 20 November 1992/Accepted 7 March 1993

Radiolabelled and fluorescent-dye-conjugated oligonucleotide probes which targeted rRNA sequences were developed for the enumeration of the ruminal bacterium Synergistesjonesii 78-1 in mixed culture. Two probes were tested, and both were highly specific for the respective complementary sequences of the target organism. Individual cells of S. jonesii in pure and mixed cultures were clearly visualized in situ by hybridization with the fluorescent-dye-conjugated probe but could not be detected in natural samples. Therefore the radiolabelled probe was used to monitor the population of S. jonesii introduced into a chemostat which simulated the rumen ecosystem. The S. jonesii probe did not hybridize to RNA extracted from the culture prior to inoculation with the target organism. After inoculation, S. jonesii rRNA represented 4.5% of the total bacterial rRNA and then rapidly declined to