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Physiology and Biochemistry

Elevation and Release of Cell-Associated Pectate Lyase in Erwinia chrysanthemi by Lithium and Sodium Chloride. John P. Mildenhall, Department of Genetics and Plant Protection, University of Fort Hare, Alice, Ciskei, South Africa; William A. Lindner(2), Bernard A. Prior(3), and Kim Tutt(4). (2)Department of Biochemistry, University of Fort Hare; (3)Department of Microbiology, University of the Orange Free State, Bloemfontein, South Africa; (4)Department of Genetics and Plant Protection, University of Fort Hare, Alice, Ciskei, South Africa. Phytopathology 78:213-217. Accepted for publication 10 August 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-213.

When Erwinia chrysanthemi was grown at a water activity (aw) value of 0.990 in the presence of LiCl (1.4% w/v) or NaCl (1.4% w/v), the cell-associated levels of pectate lyase (Pel) were 10- to 20-fold greater than in cells grown in the medium (0.998 aw) without these salts. Upon addition of these salts to the growth medium during the mid-exponential phase of growth, secretion of extracellular Pel ceased for 60 min and thereafter recommenced. Cell-associated levels of Pel increased rapidly during this period. Cells with elevated levels of Pel released the enzyme when resuspended in buffer or buffer plus sucrose (0.990 aw); however, little or no Pel was released when the cells were resuspended in buffer plus LiCl, NaCl, KCl, or sorbitol at 0.990 aw. Release of Pel was accompanied by the release of acid phosphatase (ACP). Pel release was temperature-dependent over the range investigated (1530 C). Chloroform treatment of cells released Pel and ACP but not β-galactosidase, which indicates that cell-associated Pel is accumulated in the periplasm.

Additional keywords: outer membrane, periplasmic enzyme, polygalacturonic acid transeliminase, protein export.