Coxiella burnetii is an obligate intracellular parasite that causes Q fever and progresses through its replication cycle in the phagolysosome of the host cell. In addition to its intracellular parasitic nature, it was reported that C. burnetii
transform
human perpheral lymphocyte into hairy cell. In this study, in order to clarify the DNA characteristics of C. burnetii Nine Mile strain and to make it index to detect and differentiate those in Korea, we first inoculated C. burnetii Nine Mile
strain
into
7-day-old, embryonated chick eggs. Then infected yclk sacs were harvested and homogenized 7 days after inoculation if embryos were alive, but as soon as they died if they were dead. C. burnetii organisms cultivated in yolk sac were confirmed by
Gimenez
staining and immunofluorescence staining,.
C. burnetii organisms were purified from infected yolk sacs by a series of differential centrifugations and Renografin density gradients, and their DNAs were isolated from those. And then the plasmid DNA was separated from chromosomal DNA by
CsCl-EtBr
density gradient centrifugation. The putative plasmid DNA was electrophoresed on a 0.8% agarose gel and was found to migrate as a single band behind the 12.2Kb fragment of 1Kb DNA Ladder. This indicates that C. burnetii Nine Mile strain harbor
plasmid
DNA of more larger size than 12.2Kb.
To determine the restriction endonuclease digestion pattern and to estimate the size of plasmid DNA of C. burnetii Nine Mile strain, the plasmid was digested with EcoRI and SalI and the fragments were separated by electrophoresis in agarose gels.
When
cleaved with EcoRI, the plasmid was shown to be cut in several fragments, but the bands of these fragments were not clear. When cleaved with SalI, the plasmid was found to be cut in two fragments. Upper fragment size was a little more iarger than
23.1Kb
fragments of HindIII digests of lambda DNA, and lower fragment size was similar to be a little more larger than 29.7Kd.
Therefore, it can be concluded that C. burnetii Nine Mile strain harbored plasmid DNA of a little more larger size than 29.7Kd.
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