Characterization of the Adhesive Mucilages Secreted by Live Diatom Cells using Atomic Force Microscopy

• Published in: Protist Vol. 153; no. 1; pp. 25 - 38
• Main Authors: Higgins, Michael J., Crawford, Simon A., Mulvaney, Paul, Wetherbee, Richard
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01-03-2002
• Subjects: Adhesiveness; Adhesives - chemistry; atomic force microscopy; bioadhesion; biofouling EPS (extracelluar polymeric substances); Cell Adhesion - physiology; diatoms; Diatoms - chemistry; Diatoms - metabolism; Diatoms - physiology; Diatoms - ultrastructure; Marine; Microscopy, Atomic Force - instrumentation; Microscopy, Atomic Force - methods; secretion; secretion; bioadhesion; diatoms; atomic force microscopy; biofouling EPS (extracelluar polymeric substances)
• ISSN: 1434-4610; 1618-0941
• DOI: 10.1078/1434-4610-00080

Atomic Force Microscopy (AFM) resolved the topography and mechanical properties of two distinct adhesive mucilages secreted by the marine, fouling diatom
Craspedostauros australis. Tapping mode images of live cells revealed a soft and cohesive outer mucilage layer that encased most of the diatom's siliceous wall, and force curves revealed an adhesive force of 3.58 nN. High loading force, contact mode imaging resulted in cantilever [cleaned] cell walls, which enabled the first direct observation of the active secretion of soft mucilage
via pore openings. A second adhesive mucilage consisted of strands secreted at the raphe, a distinct slit in the silica wall involved in cell-substratum attachment and motility. Force measurements revealed a raphe adhesive strand(s) resistant to breaking forces up to 60 nN, and these strands could only be detached from the AFM cantilever probe using the manual stepper motor.