This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
I'll return to blogging by starting off with a stunningly boring micrograph. Here, you can see a narrow blob, with a blob attached, and a stem below. The scalebar is 2um, so we're really up against the limits of conventional light microscopy here.
*yawn* Not the most flashy micrograph you've ever seen, most likely. But it's still kinda cool, I think: here, you can see bacterial division! This is a stalked bacterium, possibly Caulobacter or something like it -- a major model for bacterial morphogenesis, or shape-formation. At the very bottom of the stalk is a faint thickening resembling a holdfast. The constriction of the cell body is cell division in progress, via budding. The new cell is a flagellated 'swarmer'. Unfortunately, the flagellum that should extrude from the upper (swarmer) cell isn't visible here -- perhaps it's too fine and moves too quickly.
A quick glimpse of the Caulobacter lifestyle can be seen in this review by Hughes et al. 2012 (paywalled). When a swarmer settles, it grows a stalk and soon begins budding to produce swarmers (offspring, essentially). Apparently, once a stalk is formed, the bacterium is attached to the surface for life. If the chosen surface goes awry for whatever reason, it is up to the swarmer cells to detect something is wrong (via presence of leaking DNA from dead colleagues) and not settle down there.
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Were I an organised person, perhaps I'd make one day a week a bacterial day -- while protists are my first obsession, I feel not enough attention is given to bacteria from a morphological and cell biological perspective. Too many people speak of them as chemical. pathogenic or ecological agents, faceless and formless, just blobs with DNA sequences. Most bacteria have been cursed by their size: too small for light microscopy to reveal much, while electron microscopy comes with severe preparation artefacts, meaning one can't really see what a cell does live under EM. You get indirect (while awesome!) suggestions, at best. Luckily, with the development of super-resolution light microscope, the classical 200nm theoretical resolution limit (closer to about half a micron in practice) is finally being crossed, and microscopy can reveal tiny features in still-living bacterial cells! An example of what can be seen with light these days can be seen in this image from Yves Brun's lab. A little bit more detailed than my stalked blob above, eh?