Bacterial adhesion to different termite flagellates: Ultrastructural and functional evidence for distinct molecular attachment modes |
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Authors: | R Radek G Tischendorf |
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Institution: | (1) Department of Morphology and Ecology, Institute of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, D-69120 Heidelberg, Germany;(2) Institute of Plant Physiology and Microbiology, Free University of Berlin, Berlin |
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Abstract: | Summary The attachment modes of rodlike ectobiotic bacteria to the surface of two different termite flagellates were studied.Devescovina glabra was covered by laterally attached bacteria. Treatment with chemicals that disturb hydrophobic interactions and solubilize proteins removed the ectobionts. Freeze-fracture and freeze-etching electron microscopy revealed rows of intramembrane particles that occurred exclusively along the attachment sites. The adhering Gram-negative bacteria possessed an S-layer (surface layer) composed of globular protein particles. The S-layer could be removed by protein-solubilizing chemicals, e.g., urea, as shown by ultrathin-section electron microscopy. Therefore, it seems plausible that the attachment was mediated by hydrophobic interactions between the flagellate's plasma membrane and the S-layer of the bacteria. The bacteria of the second flagellate,Joenia annectens, adhered by their tips. The attachment was extremely strong. Chemicals disturbing ionic or hydrophobic bindings or solubilizing proteins did not detach the ectobionts. Globular intramembrane protein particles were preferentially found in a ringlike array at the external fracture face of the flagellate's contact sites.Abbreviations DIC
differential interference contrast
- EGTA
ethylene glycol-bis( -aminoethyl ether) N,N,N ,N -tetraacetic acid
- TEM
transmission electron microscope
- Tween
20 polyoxyethylenesorbitan |
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Keywords: | Bacterial adhesion Devescovina glabra Flagellate Freeze-etching Joenia annectens Membrane ultrastructure Termite |
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