In my previous post (Beauty inside a cell) I showed an application of a powerful microscopy technique for studying the inner structure of cells. Here I comment on the results of applying a different technique to obtain wonderful images of the surface of cells.
Researchers from University of Wales Swansea (UK) used atomic force microscopy to study the surfaces of growing hyphae during the life cycle of Streptomyces. If you're not much interested in the scientific details, just admire the textures and shapes of the pictures in large format (see fig. 1, fig. 2, fig. 3).
In addition to be visually captivating, the images support previous reports on cell differentiation processes which are characteristic of these bacteria. Young vegetative mycelium has a smooth surface and is attached to the substrate by an extracellular matrix. Then, older hyphae get covered with fibers, while loosing the extracellular matrix. Finally, the dense fibrous layer completely covers the surface of aerial mycelium and, especially, that of spores. The fibers are probably formed by the assembling of hydrophobic proteins called chaplins and rodlins; these proteins are essential for transforming the substrate-attached, vegetative mycelium into the reach-for-the-sky, aerial hyphae.
Reference:
Del Sol, R., Armstrong, I., Wright, C., Dyson, P. (2007). Characterization of Changes to the Cell Surface during the Life Cycle of Streptomyces coelicolor: Atomic Force Microscopy of Living Cells. Journal of Bacteriology, 189(6), 2219-2225. DOI: 10.1128/JB.01470-06
Images: reproduced from the same article, copyright 2007, American Society for Microbiology. Left, initial stages of assembly of a fibrous layer, prior to aerial growth. Right, an aerial hypha prior to sporulation septation, showing complete coverage of the tip by the fibrous layer.
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