AN IMPROVEMENT OF RESTRICTION ANALYSIS OF BACTERIOPHAGE DNA USING CAPILLARY ELECTROPHORESIS IN AGAROSE SOLUTION

Seven representatives of the serogroup B Staphylococcus nul eus bacter iophages, 29, 53, 55, 83A, 85, phi 11 and 80 alpha, were examined by c apillary electrophoresis (CE) for genomic homology using DNA restricti on analysis. Genomic DNA of individual bacteriophages was cleaved by H indIII restriction endonuclease, and the resulting restriction fragmen ts were separated by standard horizontal agarose slab gel electrophore sis (SGE) as well as by CE in low-melting-point agarose solutions. The number and size of restriction fragments identified by both methods w ere compared. The high separation power of CE makes it possible to ext end the restriction fragment patterns. In most of the restriction patt erns, some additional restriction fragments as small as 150 bp, not id entified by SGE, were detected. With respect to speed, high separation efficiency, low sample consumption and automation, CE offers a simple procedure for processing of multiple samples cost-effectively in a re asonable time. The comparison of the complemented restriction patterns of the different phage strains and the subsequent identification of t heir common fragments leads to a deeper understanding of their phyloge netic relationships. The genome homologies expressed for individual ph age pairs in terms of coefficient F values ranged from 15 to 69%. Thes e values are in good accordance with the degree of DNA homology of the se phages as determined by DNA hybridization studies and thermal denat uration analysis of DNA by other authors. The total size of each phage genome was estimated by adding the sizes of individual restriction fr agments.