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CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA
Lessie, T. G. AND B. D. Manning. CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA. Presented at Biotechnology Risk Assessment Symposium, Pensacola, FL, June 06 - 08, 1995.
We have used CHEF gel electrophoresis to screen preparations of large DNA from different Burkholderia cepacia isolates for the presence of DNA species corresponding to the linearized forms of the three chromosomes of 3.4,2.5, and 0.9 Mb identified in B. cepacia strain 17616. DNA preparations from the different isolates contained between two and four linearized replicons in the size range of 1.1 to 5.8 Mb, confirming that chromosomal multiplicity is common among B. cepacia strains. Estimates of overall genome size varied between 4.6 and 8.5 Mb. We also compared the distribution of r-RNA (rrn) genes in selected isolates by determining the number and sizes of DNA fragments generated by treatment of their DNA with Ceu I, an enzyme which appears to cleave exclusively within 23S r-RNA genes. Ceu I fragment patterns of digests of DNA from strain 17616 were consistent with earlier results suggesting the presence of three rrn operons on the 3.4-Mb replicon, one on the 2.5-Mb replicon, and one on the 0.9-Mb replicon. Other B. cepacia isolates appeared to contain six sets of rrn genes.