Starvation-induced changes in the cell surface of Azospirillum lipoferum

Three starvation regimes (a deficient culture medium, a saline buffer solut ion and distilled water) were evaluated for their possible effect on cell s urface characteristics of Azospirillum lipoferum 1842 related to the initia l adsorption of the bacterium to surfaces. The bacteria survived for 7 days in all media although they did not multiply. Upon transfer from a rich gro wth medium (nutrient agar) to starvation conditions, cell surface hydrophob icity dropped sharply but recovered its initial value within 24 to 48 h, ex cept in phosphate-buffered saline, the length of the recovery period depend ing on the starvation medium. Starvation affected the sugar affinity of the A. lipoferum cell surface mainly towards p-aminophenyl-alpha-d-mannopyrano side, to a lesser extent to glucose, but not to other monosaccharides teste d. Starvation changed the concentration of several cell surface proteins bu t did not induce the synthesis of new ones. The cell surface hydrophobic pr otein (43 kDa) of A. lipoferum 1842 was unaffected by any starvation treatm ent for a period of up to 48 h, but later disappeared. These data showed th at starvation is not a major factor in inducing changes in the cell surface which lead to the primary phase of attachment of Azospirillum to surfaces. (C) 2000 Federation of European Microbiological Societies. Published by El sevier Science B.V. All rights reserved.