Ionic requirements of Treponema pallidum. I. Sodium and potassium

Ionic requirements of Treponema pallidum. III. Divalent ions

Doak, G. O. (University of North Carolina, Chapel Hill), Leon D. Freedman, and John W. Clark, Jr. Ionic requirements of Treponema pallidum. III. Divalent ions. J. Bacteriol. 82:909-912. 1961.-Suspensions of Treponema pallidum, prepared by extracting the testes of syphilitic rabbits with normal rabbit serum or with a culture medium, were shaken with Amberlite IRC-50 resin in the sodium ion form. This procedure did not noticeably reduce the number of motile organisms, but markedly decreased their ability to survive in vitro. The addition of calcium, strontium, or barium ions to the treated suspensions largely restored this loss of motility. These same ions, when added to suspensions of T. pallidum not treated with the ion exchange resin, were without effect. Magnesium ion also had a beneficial effect, but considerably less than that produced by calcium ion. Cobaltous, manganous, ferrous, and zinc ions gave no beneficial effect, and, except for manganous ion, were toxic to the organisms at 5 x 10(-3)m.

Retention of motility and virulence of Treponema pallidum (Nichols strain) in vitro

A maintenance medium for Treponema pallidum was designed to hold its Eh at the optimum for that organism, -10 to -110 mV. After 100% motile (freshly harvested) T. pallidum was inoculated into the medium, the motility of the treponemes decreased to 80% after 2 days, 50% after 3.5 days, and 0% after 9 days during incubation at 34 C. Full virulence was retained for 2 days, but it dropped rapidly thereafter, and the treponemes became avirulent by day 5.