title: The urea requirement and urease production of some human species of T-mycoplasmas.
abstract: Seven species of human T-mycoplasmas that grow in Fraction A and 20 mug urea/ml died when the urea was omitted. Two species would not grow in Fraction A broth containing 10 mug/urea/ml. The other five strains grew in broth containing 10 mug  urea/ml and were adapted by serial passage in broth containing decreasing concentrations of urea to grow in broth containing 2.5 mug/ml urea, but not in broth containing 1.25 mug/ml. Therefore the minimal urea requirement is not the same for the growth of all strains of T-mycoplasmas. In exponential phase broth cultures, urease was detected only intracellularly, none being found in the medium.
mesh_terms: D006801:Humans; D013045:Species Specificity; D014508:Urea / Q000378:metabolism*; D014509:Ureaplasma / Q000201:enzymology / Q000378:metabolism*; D014510:Urease / Q000096:biosynthesis*
chemical_list: D014508:Urea; D014510:Urease