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Description of Two Bacteriophages Active Against Lotus Rhizobia

Bruch, C. W., Allen, O. N.
Soil Science Society of America journal 1955 v.19 no.2 pp. 175-179
Lotus corniculatus, bacteriophages, calcium, greenhouse experimentation, host plants, inoculum, pH, plant response, races, temperature, viability, yeasts
The isolation and proliferation of four races of phage against rhizobia from nodules of Lotus corniculatus are described. Growth characteristics of two races, P-2 and P-11, are given in detail. Neither of these two phages showed differences in plaque morphology. Higher titers of these races were not obtained in media containing increased increments of yeast water and calcium as compared with modified medium 79. Optimum pH level for phage proliferation and viability ranged between pH 6.5 and 7.5. Each phage maintained its titer for 60 days upon storage at 2° C., but was increasingly less stable at 10° C., 25° C., and 37° C. Optimum temperature for proliferation was 27 to 30° C.; inactivation was rapid at 45° C., 50° C., and 55° C. Alterations in infectiveness and effectiveness, as judged by host plant response, were not obtained when (a) phage-resistant strains and (b) suspensions of phage particles and susceptible rhizobia (ratio 3:1) were used as inocula in greenhouse tests.