title: Conditions that affect the colorimetric analysis of lipopolysaccharide from Escherichia coli and Treponema pallidum.
abstract: Material extracted from the Nichols nonpathogenic strain of Treponema pallidum by phenol-water was analyzed by employing a recently reported colorimetric test for detection of lipopolysaccharide (LPS). The fraction isolated from T. pallidum, in combination with the reagent dye, absorbed maximally at a wavelength in the range reported to be positive for LPS. Comparison of this reaction to that of a commercial preparation of Escherichia coli LPS revealed that time and temperature of incubation of the LPS-dye complexes were important variables which had marked but different effects on the LPS of the two sources. However, with careful control of these parameters, concentration-dependent standard curves were established for LPS of both sources. Our results indicate the cell wall of T. pallidum is similar to that of gram-negative organisms.
mesh_terms: D000042:Absorption; D003124:Colorimetry / Q000592:standards*; D004396:Coloring Agents; D004926:Escherichia coli / Q000032:analysis*; D008070:Lipopolysaccharides / Q000032:analysis*; D008722:Methods; D009281:Naphthalenes; D011135:Polysaccharides, Bacterial / Q000032:analysis*; D013696:Temperature; D013844:Thiazoles; D013997:Time Factors; D014210:Treponema pallidum / Q000032:analysis*
chemical_list: D004396:Coloring Agents; D008070:Lipopolysaccharides; D009281:Naphthalenes; D011135:Polysaccharides, Bacterial; D013844:Thiazoles