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Violet-pigmented bacteria, which have been described since the end of the 19th century, are occasionally the causative agent of septicemia and sometimes cause fatal infection in human and animals. Bacteria, producing violet colonies due to the production of a nondiffusible pigment violacein, were classified as a redefined genus Chromobacterium.(More)
Initially an eleven variable, sixteen assay 215−11 fractional factorial design, was used to determine the key factors in the production of violacein produced by Chromobacterium violaceum, CCT 3496. Subsequently five and three factor central composite designs were executed to determine response surfaces with the aim of optimizing cellular mass and crude(More)
Extracellular production of metal nanoparticles by several strains of the fungus Fusarium oxysporum was carried out. It was found that aqueous silver ions when exposed to several Fusarium oxysporum strains are reduced in solution, thereby leading to the formation of silver hydrosol. The silver nanoparticles were in the range of 20-50 nm in dimensions. The(More)
Radio-isotope studies indicated not only that L-tryptophan can serve as carbon source for synthesis of the trypanocide, violacein by Chromobacterium violaceum (BB-78 strain) but also that isatin and indole 3-acetic acid are both important metabolic intermediates. Using 3-indolyl [2-(14)C] and [1-(14)C] acetic acid, it was found that the carboxylic carbon(More)
There has been increasing interest in extracellular enzymes from white rot fungi, such as lignin and manganese peroxidases, and laccases, due to their potential to degrade both highly toxic phenolic compounds and lignin. The optimum cultivation conditions for laccase production in semi-solid and liquid medium by Trametes versicolor, Trametes villosa,(More)
Violacein, a pigment isolated from Chromobacterium violaceum in the Amazon River, presents diverse biologic properties and attracts interest as a consequence of its antileukemic activity. Elucidation of the molecular mechanism mediating this activity will provide further relevant information for understanding its effects on the cellular physiology of(More)
1. Chromobacterium violaceum (strain BB-78 isolated in Brazil) produces violacein, a substance potentially useful in phototherapy and with antibiotic and trypanocide activity. Culture conditions were optimized for the production of violacein and changes in nutrients, temperature and pH were correlated to cellular growth. 2. Methionine was the only absolute(More)
AIMS Four selected fungi were screened for their ability to decolourize a textile effluent and commercial reactive dyes in a solid medium. METHODS AND RESULTS Ligninolytic enzymes activities (lignin peroxidase, manganese peroxidase and laccase) and siderophores presence were monitored in decolourized plates. RESULTS The results showed low lignin(More)
Graphene and its derivatives are promising candidates for important biomedical applications because of their versatility. The prospective use of graphene-based materials in a biological context requires a detailed comprehension of the toxicity of these materials. Moreover, due to the expanding applications of nanotechnology, human and environmental(More)
Violacein, a pigment produced by Chromobacterium violaceum, is reported to be a potential drug for the treatment of Chagas' disease. Violacein is also effective against leukemia and lymphoma cells in culture (IC50 10−8 M). Changes in the nuclear acid content, 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide reduction and neutral red uptake in(More)