RT Journal Article SR Electronic(1) A1 TAYLOR-ROBINSON, D. A1 WILLIAMS, M. H. A1 HAIG, D. A.YR 1968 T1 The Isolation and Comparative Biological and Physical Characteristics of T-mycoplasmas of Cattle JF Microbiology, VO 54 IS 1 SP 33 OP 46 DO https://doi.org/10.1099/00221287-54-1-33 PB Microbiology Society, SN 1465-2080, AB SUMMARY T-mycoplasmas were isolated by a ‘colour-change’ technique, involving the metabolism of urea, from 16 of 49 slaughtered cows (33%). They were encountered more often in the urethra and bladder than in the vagina. Isolations were made usually within 2 days of incubation but occasionally 5 days was required. T-mycoplasmas were isolated in medium without inhibitors from urethral scrapings of a cow and from seminal fluid of a bull. On solid medium, bovine T-mycoplasmas produced colonies of 5-12μ which were similar to those produced by a T-mycoplasma from the human urogenital tract. In liquid medium, the growth cycle of bovine T-mycoplasmas was similar to that of human T-mycoplasmas, being more rapid than that of large colony-forming (classical) mycoplasmas. The presence of serum in the medium was necessary for growth. T-mycoplasmas of bovine origin were affected in a similar way to those of human origin when subjected to ether, heat, freezing and thawing, freeze-drying, antibiotics and thallium acetate; they were more sensitive to erythromycin and thallium acetate than some classical mycoplasmas. The size of the minimal reproductive forms of bovine and human T-mycoplasmas and a classical mycoplasma, Mycoplasma hyorhinis, was similar as judged by filtration experiments. Electron microscopy of bovine and human T-mycoplasmas revealed cells which varied in size from 80 mμ, to 420 mμ, and which were bounded by a triple-layered membrane, features similar to known classical mycoplasmas., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-54-1-33