Video A

This video, taken with differential interference microscopy at 1000x, shows both the tsunami flow of all cells moving in one direction due to sloshing (this is not motility) as well as cell motility: many cells swimming independently in different directions powered by their flagella. You will see swimming, tumbling and spinning motions of motile cells.

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Science & Technology

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• 2910

[AneaSashiko]

What bacterium us being shown here?

[2910videos]

A Bacillus sp., not identified to species level isolated by a student

[ScientiaVeritasEtLux]

what is the best way to see motility in bacillus bacteria? I have an agar plate sample of some soil bacteria I found and was given a bit of a scare when I realized it looks a lot like B. anthracis (I live on farmland, so this isn't totally ludicrous). I read that B. cereus (it's closest cousin) is motile, while B. anthracis is not. So, in what medium would it be easiest to see any movement? Just water? Nutrient broth? I'd like to determine what species exactly the culture is.

[2910videos]

Take some growth from the edge of colony off agar (edge cells are younger.) Mix in drop of water. Place on coverslip, view. Look for cells moving under their own steam in different directions as opposed to cells drifting with the flow. If colonies old (> 1 week) transfer to new plate. Older cells will form spores--survival structure--and will no longer be motile. Hope that helps.

[ScientiaVeritasEtLux]

Thanks, that did help. I'm pretty sure it's Bacillus cereus that I'm looking at.

[AneaSashiko]

Thank you ^.^