02071nas a2200313   4500000000100000008004100001260001300042653001200055653001700067653002100084653002100105653001600126653002200142653001900164653001500183653001800198653004800216653001300264653001700277653001300294100001600307700001700323700001400340245008700354300001100441490000700452520128400459022001401743       1964                            d  c1964 Dec10aAnimals10aArthrobacter10aBiological Assay10aChelating Agents10aEdetic Acid10aGrowth Substances10aHydroxylamines10aMetabolism10aMycobacterium10aMycobacterium avium subsp. paratuberculosis10aOxazoles10aPharmacology10aResearch1 aANTOINE A D1 aMORRISON N E1 aHANKS J H00aSPECIFICITY OF IMPROVED METHODS FOR MYCOBACTIN BIOASSAY BY ARTHROBACTER TERREGENS.  a1672-70 v883 a<p>Antoine, Alan D. (Johns Hopkins University-Leonard Wood Memorial Leprosy Research Laboratory, Baltimore, Md.), Norman E. Morrison, and John H. Hanks. Specificity of improved methods for mycobactin bioassay by Arthrobacter terregens. J. Bacteriol. 88:1672-1677. 1964.-Arthrobacter terregens was used to assay mycobactin, a growth factor for Mycobacterium paratuberculosis. Improved techniques permit the assay of mycobactin within 3 to 4 days by agarplate or liquid-medium methods. For the agarplate method, Arthrobacter terregens gave linear increases in zonal growth at mycobactin concentrations of 0.07 to 0.30 mug per spot; for the liquid-medium method, linear increases in turbidimetric growth occurred at 0.05 to 0.27 mug/ml. Specificity studies show that the mycobactin hydrolytic products, cobactin and mycobactic acid, function as growth stimulators, but the high concentrations required would produce only minimal interference in mycobactin assays. Furthermore, the response to mycobactic acid is characterized by a delayed response of 3 days. Various synthetic hydroxylamine-containing compounds and metalchelating agents cannot replace the biological activity of mycobactin. Diacetylmycobactin is 7.4 times more effective than mycobactin as a growth stimulator.</p>  a0021-9193