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Physiology and Biochemistry

Characterization of Membrane Proteins of Xanthomonas campestris pv. campestris. Gerald V. Minsavage, Department of Plant Pathology, University of Georgia, Georgia Experiment Station, Experiment 30212, Present address: Asgrow Seed Company, P.O. Box L, San Juan Bautista, CA 95045; N. W. Schaad, Department of Plant, Soil and Entomological Science, University of Idaho, Moscow 83843. Phytopathology 73:747-755. Accepted for publication 6 December 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-747.

Total envelope proteins of Xanthomonas campestris pv. campestris (hereafter referred to in this abstract as X. campestris) were purified by differential centrifugation of cells that were disrupted in a French pressure cell. The proteins were separated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Proteins of total envelopes of X. campestris presented a unique pattern when compared with profiles of proteins of other Gram-negative rod-shaped bacteria, including other pathovars of X. campestris. There were four major bands of 62, 44, 26, and 23 kdaltons and approximately 24 minor bands. Whereas no differences occurred in profiles of membranes of cells of different-aged cultures, differences were observed with a temperature shift from 30 to 37 C. Two proteins, the 44-kdalton major polypeptide and a 107-kdalton polypeptide, were found to be heat modifiable.