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 #55 : Conjugation, and some pairing issues
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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Pictures Considered #51 : Headful Packaging, Literally...
by Christoph
For more than two decades we have known that the double-stranded DNA of phages is neatly rolled up in their capsids and fills them completely. Cerritelli et al. (1997) have demonstrated this for coliphage T7, and later Jiang et al. (2006) for Salmonella phage ε15. Yet, with a length of ~40 kb, both phages have more 'medium sized' genomes, and it is fine to learn now...
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Pictures Considered #50 : The Four Kingdoms of Nature
by Christoph
We often talk sloppily of «algae» or «protists» on these pages when we consider, rarely enough, unicellular eukaryotes. For my part, I attach little importance to biological systematics or taxonomy per se because I'm more interested in learning how living beings go about their business than in sorting them into various drawers. Therefore I mostly confine myself to the names of the...
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Pictures Considered #49 : C-Reactive Protein
by Elio
Among the blood tests that your doctor may prescribes is the one for C-Reactive Protein (CRP). What is it? CRP is a protein made by the liver in response to inflammation anywhere in the body, so a positive result will alert the physician that something along those lines is going on some place within you.
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Pictures Considered #48 : Contributions to the Biology of the Bacilli
by Roberto
It was fifteen or twenty years ago, I can't recall the year any more. But I vividly remember walking into Harvard's Farlow Botany Library, being shown to a seat next to an elegant wooden table, and asked to don a pair of white gloves. The protocol stemmed from the fact that I had requested to see an original of the second volume of the journal Beiträge zur Biologie der Pflanzen (Contributions to the Biology of Plants), from 1876.
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Pictures Considered #47 : Phages in the Gardens
by Roberto
A few weeks ago, I found myself aimlessly exploring the garden of the Palace of Holyroodhouse (Edinburgh, Scotland), which has served as the principal residence of the Kings and Queens of Scots since the 16th century.
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Pictures Considered #46 : Fairy Lights (nanometer scale)
by Christoph
This post features electrons, which are among the smallest things possible. There are, of course, even much smaller things than electrons but this blog keeps clear of the quantum realm, most of the time. Yet to make up for the electrons' teensyness – if they could keep still some 4 × 1021 would fit into...
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