, AND WILLIAM L. STEPHENS. Pigmentation and taxonomy of the genus Xanthomonas. J. Bacteriol. 87:293-302. 1964.-The colonies formed by phytopathogenic bacteria of the genus Xanthomonas are typically yellow in color. This chromogenesis stems from the presence in all yellow xanthomonads of a particular carotenoid pigment. This unique "Xanthomonas-carotenoid," which has not been found in any yellow nonxanthomonad, is characterized herein to the extent required for its recognition by relatively simple screening procedures. In general, the occurrence of a carotenoid "alcohol" with absorption maxima at 418, 437, and 463 myu (petroleum ether)-in a gram-negative, polarly-flagellated, oxidative, rod-shaped bacterium-would suggest placement of that microorganism in the genus Xanthomonas.

No abstract

Stephens, William L. (University of California, Davis), and Mortimer P. Starr . Localization of carotenoid pigment in the cytoplasmic membrane of Xanthomonas juglandis . J. Bacteriol. 86: 1070–1074. 1963.—The kinetics of release of carotenoid pigment from cells of Xanthomonas juglandis , disrupted by sonic or ballistic treatment, showed the pigment to be localized in the cell envelope. Cells subjected to ballistic disintegration released carotenoid at a rate identical to that of a membrane component (reduced nicotinamide adenine dinucleotide oxidase) and at a slightly higher rate than a wall component (hexosamine). Thus, the membrane portion of the cell envelope is the most probable locus of the unique carotenoid pigment of X. juglandis .

No abstract