by Christoph
The last thirty years have been an "eye-opening" journey for microbial cell biologists, quite literally. I am, of course, talking about fluorescent labeling of individual cell components and the non‑invasive observation of their "behavior" in living bacterial cells. Just recently, I considered a video clip about Vibrio cholerae harpooning DNA. Now again a video clip, about...
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Pictures Considered #61: how FtsZ-rings get shoveled to midcell in vitro
Pictures Considered #60: Vibrio cholerae harpooning DNA
by Christoph
Let me start with an adage: a picture is worth a thousand words. Can this also be valid for video snippets? I think so. Here you see a few seconds of a looping video showing how a cholera bacterium extends a pilus, attaches the tip to DNA in the environment, and then retracts it. Worth a thousand words? Yes, sure, but also deserving 1,000 words...
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Pictures Considered #59: Inside a Choanoflagellate
by Roberto
Choanoflagellates (endearingly referred to as "choanos") are the closest living relative of animals and as such they can provide insights into the evolution of animal multicellularity. Interestingly, at least two choano developmental features are induced by bacterial products.
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Pictures Considered #58: Visualizing Introns
When we talk about genes and genomes today, we almost reflexively thinks of long strings of the letters G, A, T, and C. And by reading sequences, we easily detect stretches that code for proteins. We detect promoters, transcription factor binding motifs, start/stop signals for transcription, signals where introns are removed by splicing from primary transcripts... Read more →
Pictures Considered #57 : Coloring a Cell
by Christoph
Our ability to visually perceive and discriminate is always slighly overwhelmed by black-and-white images. Especially, of course, when the objects depicted are outside our trained, familiar size spectrum, such as bacterial cells and their innards. Take for example Figure 1, the cryo-ET image of a tiny...
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Pictures Considered #56 : A Pinch of Salt
by Christoph
Microbiologists deal with salt, sodium chloride, all the time. Most growth media for our cherished research contain at least "a pinch of salt." Or we need salt as a component of buffers for biochemical experiments that require defined concentrations of Na+ and Cl− ions. However, we usually only see crystalline salt when we take...
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Pictures Considered #55 : Conjugation, and some pairing issues
by Christoph
If you've ever taken a class on bacterial genetics, either recently or in the last few decades, you've no doubt seen this image: the conjugation of two bacterial cells (Figure 1). And if you found this image so self-explanatory that you didn't bother to ask for the source, you're not alone. The internet is replete with it, in varying...
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Pictures Considered #54 : Mitochondria can't swim...
by Christoph
...and get pushed around instead. Not equipped with flagella for propelling or Type IV pili for twitching they can't actively move. But one step at a time. If you recall what you know about mitochondria, you may picture them as ovoid or bean-shaped organelles, housemates floating in the eukaryotic cytoplasm. They are...
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Pictures Considered #53 : The ocean water column is profoundly dark...
by Christoph
...for the most part. And it's vastly deeper than the diagram Roberto showed in his recent post "The Biological Pump." The euphotic and mesopelagic zone sizes are correct, but do not even approximately corelate with their vertical representation in the diagram. Why is this a point...
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Pictures Considered #52 : Streptomyces stacks Z-rings...
by Christoph
Streptomyces stacks Z-rings... into ladders inside its aerial/sporogenic hyphae. If this sentence strikes you as a barrage of jargon or just gibberish, don't despair, help is coming. First, enjoy the "light show" in the 20‑second video clip on the right side. It runs in loop, so you can follow more than...
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