| Abstract: | Twenty-three temperate phages of Lactobacillus salivarius isolated from human feces were studied as to their morphological, biological, and serological properties. (1) Among 30 strains of L. salivarius tested, 23 strains were lysed by induction with mitomycin C (MC). In all these lysates, phage particles were detected by electron microscopic examination. (2) These phages were morphologically divided into three groups: particles with a regular hexagonal head and a long flexible tail; particles having a regular hexagonal head with or without a short tail-like structure; particles with an elongated head and a long noncontractile tail. (3) Only two, phage 223 having an elongated head and phage 227 with a regular hexagonal head and a long noncontractile tail, produced tiny and very turbid plaques on several host bacteria. Six phages could produce only inhibition zones, ranging from complete inhibition through partial inhibition to normal growth by a serial dilution spot test. (4) All these killer particles could also inhibit the growth of their producer cells. (5) A serological relationship was observed between temperate phages and killer particles, and this was somewhat consistent with the morphological groupings. |
