Surface properties from the S-layer of Clostridium thermosaccharolyticum D120-70 and Clostridium thermohydrosulfuricum L111-69 |
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Authors: | Margit Sára Inge Kalsner Uwe B. Sleytr |
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Affiliation: | (1) Zentrum für Ultrastrukturforschung, Universität für Bodenkultur, A-1180 Wien, Austria;(2) Ludwig Boltzmann Institut für Ultrastrukturforschung, Universität für Bodenkultur, A-1180 Wien, Austria |
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Abstract: | Labelling experiments using a positively charged topographical marker for electron microscopy, polycationized ferritin, showed that the S-layers of two closely related clostridia Clostridium thermohydrosulfuricum L111-69 and C. thermosaccharolyticum D120-70 do not exhibit a net negative charge, as usually observed for bacterial cell surfaces. Chemical modification of reactive sites confirmed that amino and carboxyl groups are exposed on the S-layer surface of both strains. Amino-specific, bifunctional agents crosslinked both S-layer lattices. Studies with carbodiimides revealed that only the S-layer surface of C. thermohydrosulfuricum L111-69 had amino and carboxyl groups closely enough aligned to permit electrostatic interactions between the constituent protomers. The regular structure of this S-layer lattice was lost upon converting the carboxyl groups into neutral groups by amidation. Disintegration of both S-layer lattices occurred upon N-acetylation or N-succinylation of the free amino groups. Adhesion experiments showed that in neutral and weakly alkaline environment whole cells of C. thermosaccharolyticum D120-70 exhibited a stronger tendency to bind to charged surfaces than whole cells of C. thermohydrosulfuricum L111-69, but showed a lower tendency to bind to hydrophobic materials. |
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Keywords: | Bacterial cell wall S-layer Crystalline surface layers Surface charge Surface hydrophobicity Clostridium thermohydrosulfuricum Clostridium thermosaccharolyticum |
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