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Cytochromes in Virulent Fixed L Forms of Agrobacterium tumefaciens. R. Beltrá, Instituto Jaime Ferrán de Microbiología, del Consejo Superior de Investigaciones Científicas, Joaquín Costa 32, Madrid, Spain; J. Rodríguez de Lecea(2), and D. López-Abella(3). (2)(3)Instituto Jaime Ferrán de Microbiología, del Consejo Superior de Investigaciones Científicas, Joaquín Costa 32, Madrid, Spain. Phytopathology 62:933-935. DOI: 10.1094/Phyto-62-933.

We found that the normal bacterial form of Agrobacterium tumefaciens was oxidase-positive, and the reduced minus oxidized difference spectrum at room temperature indicates the presence of b 559 and c 550 cytochromes. Under the same conditions, the virulent fixed L forms of the same bacterial strain were oxidase-negative, and showed the presence of only b 560 cytochrome. These experiments seem to show that oxidase-positive reaction is linked to the presence of a cytochrome c, and also that the physiological and respiratory processes in L forms of Agrobacterium tumefaciens are different from those of the normal form of the bacterium.