Growth, pectate lyase production and solute accumulation by Erwinia chrysanthemi under osmotic stress: effect of osmoprotectants |
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| Authors: | B.A. Prior E. Hewitt E.V. Brandt A. Clarke J.P. Mildenhall |
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| Affiliation: | Departments of Microbiology and Biochemistry;Chemistry, University of the Orange Free State, Bloemfontein;Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa |
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| Abstract: | Glycine betaine strongly stimulated the growth rate of five strains of Erwinia chrysanthemi when grown in a synthetic medium at 0·986, 0·983 and 0·980 a w (NaCl) whereas in four strains, little effect was observed compared with the control. Proline, dimethyl glycine, carnitine and pipecolic acid also actedas osmoprotectants. Glutamate and trehalose, commonly accumulated by enteric bacteria in response to osmotic stress, failed to act as osmoprotectants when supplied exogenously. Glycine betaine and pipecolic acid partially overcame the inhibition of pectate lyase release by NaCl in strain ECC. 13C NMR spectroscopy of two osmotically-stressed strains showed that glycine betaine was accumulated intracellularly from synthetic media containing the exogenous osmoprotectant. However, both strains also synthesized and accumulated trehalose in addition to glycine betaine in response to osmotic stress in complex media containing glycine betaine. |
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