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Violacein is a purple pigment typically produced by species of Chromobacterium and Janthinobacterium. A soil isolate, identified as Janthinobacterium, was studied. Maximal pigmentation occurred at 250C under aerobic conditions in the Keeble and Cross medium. Intracellular pigment was shown to be located in the cell membrane. Comparision of pigment production and growth curves indicated that violacein is synthesized in the cell and released into the environment possibly as a result of cell lysis. Extracellular pigment is water soluble, makes up 60% of the total pigment and shows a blue shift when compared to solvent extracted pigment. Results from purification indicated that the pigment is non-covalently bound to a small protein and aggregated into a larger molecule.

The mechanism of protection by carotenoids against photodynamic killing in Curtobacterium flaccumfaciens pathover poinsettiae (C. poinsettiae) was studied using pigment mutants isolated by treatment with nitrosoguanidine and DNA gyrase inhibitors. Growth rates, pigment composition, pigment levels and the ultrastructure of the wild-type streptomycin resistant strain of G. poinsettiae (wt-str) and all mutants were compared. One mutant, NTG-1, lacked colored carotenoids, and another, NTG-2, was a slow growing mutant containing low levels (14%) of wild-type carotenoid pigments. Except for NTG-1, the other pigment mutants had different proportions of the same pigments found in the wild type as determined by high performance liquid chromatography (HPLC). Only NTG-2 was morphologically distinct at the ultrastructural level.

LD2668 .T4 1949 P35 / Master of Science

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The pigment-lipid complexes of the phytopathogen, Xanthomonas juglandis, were studied. Experiments were designed to determine the cellular location of the complexes and whether or not they are associated with protein.

Corynebacterium poinsettiae mutant strains blocked in carotenoid biosynthesis were obtained by treatment with the mutagen N-methyl-N1-nitro-N-nitrosoguanidine. Additional carotenoid (Crt) mutant strains were obtained from a previous study conducted in our laboratory. Fifty-nine Crt mutants affected in carotenoid biosynthesis were examined by a normal phase high performance liquid chromatography (HPLC) system. Pigment extracts of Crt mutants and C. poinsettiae wild type strains were resolved by an isocratic system with hexane:acetone:dicholoromethane, 11.35:1.73:1.00 (by vol.) as the eluting solvent. In addition to the five major peaks, twelve minor peaks were observed in the wild type C. poinsettiae strain used in this study. Crt mutant and wild type strain peak heights were measured from the individual chromatograms and the peak height data set created was analyzed using the Statistical Analysis System program to perform a cluster analysis. The cluster analysis revealed five carotenoid mutant groups. Carotenoid pigments which accumulated or were absent in each of the cluster groups are reported. Cluster group 1 mutants (CrtA) are blocked in the dehydrogenase(s) which is(are) responsible for the dehydrogenations between phytoene and lycopene. Cluster group 2 mutants (CrtB) appear to be blocked at a second dehydrogenase specific for the dehydrogenation from C.p. 470 to C.p. 496. Cluster group 3 mutants (CrtC) are blocked at a cyclization step in the pathway which involves cyclization of C.p. 496 to C.p. 470 and which may cyclize C.p. 473 to C.p. 450. The genes CrtA and CrtB map only 0.5 map units from each other while CrtA and CrtC map 2.1 map units from one another. Mutants which accumulate end products but which lack certain precursors indicate a branched pathway for pigment biosynthesis exists in this organism. Media for the formation, fusion and regeneration of C. poinsettiae protoplasts are reported and a protocol for the use of these media in genetic crosses of strains blocked in carotenoid biosynthesis is described. While isolating antibiotic resistant mutants useful in genetic analyses, novobiocin resistant mutants were observed to have a distinctly different colony pigment phenotype as compared to the wild type strain. HPLC chromatograms of a novobiocin resistant strain showed a distinctly different carotenoid pigment profile. The results provide evidence for differential gene expression in the carotenoid biosynthetic pathway when these mutants are grown in the presence of novobiocin.

This investigation has for its aim the explanation of growth and pigment production of Micrococcus flavus, Micrococcus roseus, Micrococcus subvitreus, and Sarcina citrea by the addition of various nutrient test materials to a standard culture medium.

Little is known concerning the production and significance of bacterial pigments. There is seemingly an open field for studying the effects produced by varying the nutritive content of culture media upon which organisms are grown. This has led to an especial interest in, and the purpose of this investigation.