Characterization of a prolate-headed bacteriophage of Lactobacillus delbrueckii subsp. lactis, and its DNA homology with isometric-headed phages.

A new Lactobacillus delbrueckii subsp. lactis bacteriophage, JCL 1032, was characterized. JCL 1032 had a small, elongated prolate head, and a long non-contractile tail with cross-bars. The restriction map of JCL 1032 genome was constructed with five endonucleases. The genome was 45.8 kb in size, and it had cohesive ends (cos). Molecular masses of the phage structural proteins were also determined. JCL 1032 showed DNA homology with morphologically dissimilar, isometric-headed phages of Lb. delbrueckii (subsp. lactis and subsp. bulgaricus) when analyzed by Southern hybridization. Although in general JCL 1032 was only distantly related to isometric-headed phages, there were also a few short highly homologous (minimal homology 84%) DNA regions.