Macrofiber properties of the Bacillus subtilis strain carrying a transposon insertion

Recently, a new strain of B. subtilis (Bull913) carrying Tn917, a Streptococcus-derived transposon that confers erythromycin and lincomycin resistance, in the host chromosome has been isolated that grows as multistrand helical structures. Bull913 can produce macrofibers whose properties are like another B. subtilis strain FJ7. FJ7 is a lyt-2 mutant produced by chemical mutagenesis which can form macrofibers with twists ranging from right to left handed. Bull913 also has this spectrum of twisted states. Bull913 macrofibers are similar to FJ7 but are longer lived than FJ7. The Macrofiber properties of Bull913 were compared to FJ7 using growth in liquid media supplemented with (NH₄)₂SO₄ or MgSO₄ -- conditions giving LH or RH macrofibers, respectively for FJ7. The autolysin activities and cell walls substrate properties of Bull913 were biochemically analyzed and compared to those of strains 168 and FJ7. Polyacrylamide gel electrophoresis (PAGE) was used to compare the wall proteins from all three strains. Finally, genetic studies of Bull913 were carried out to determine if the defect in Bull913 is in the lyt-1, lyt-2 or lyt-15 genes, or in a new gene. Both biochemical analysis and genetic studies suggest that Bul1913 carries Tn917 in the lyt-2 gene