Pure Biology
apalazzo | March 17, 2006From the archives, here's a micrograph of a fibroblast (connective tissue cell) adherring to fibronectin coated coverslip. The cell was immunostained for regular microtubules (red) and modified detyrosinated microtubules (green, although since these are only partialy modified red+green = yellow).
Here are some strange crystals that appeared on my coverslip one day, I had just to take a picture:
apalazzo | March 12, 2006
Fatty acid synthesis consists of tethering an an acetyl group (2 carbons) to ACP (Acyl Carrier protein) that then bounces around to 5 different enzymes to add 2 carbons to the end of the acetyl group. This process is repeated, each cycle resulting in the addition of two extra carbons. Eventually the long lipid chain is released from ACP resulting in a free fatty acid that is 16 (palmate), 18 (Stearate) or some other number of carbons long. To learn more on fatty acid synthesis, follow this link to a great summary from the Chemistry department at the University of Arkon.
In fungi these 6…
apalazzo | March 10, 2006Last night, my wife and I had dinner with a friend of ours from the Szostak Lab (yes at Buddha's Delight - I had the "beef" taro stirfry).
There we discussed Capote (we just saw the movie) and the existence of ribose in a pre-biotic earth. Apparently it is unlikely that sugars, such as ribose, would have been in high concentrations in the hypothetical chemistry of primitive earth (see her PNAS paper). Although sugars are easily generated (spontaneously from formaldehyde), they decay very rapidly - thus at steady state it's likely that there wasn't much sugar around. Sugars form the backbone…
apalazzo | March 6, 2006Well in a previous entry I wrote:
Generally, prokaryotes are devoid of membrane-bound organelles (including the nucleus, mitochondria, the endoplasmic reticulum), and their cytoskeletal systems are quite simple.
And I got a comment about magnetosomes, small membrane bound organelles found in certain bacteria that contain magnetite crystals. These organelles are usually aligned in long chains that orient along the earth's magnetic field and help these critters to swim north or south. (Some examples of magnetosomes are shown on the left).
This comment (and my quote) reminded me of this great…
apalazzo | March 2, 2006I just read a fascinating "hypothesis" in the latest issue of Nature entitled Introns and the origin of nucleus cytosol compartmentalization.
The greatest divide in the living world exists between prokaryotes and eukaryotes (yes I know, there are viruses ... but lets not get off topic!).
Generally, prokaryotes are devoid of membrane-bound organelles (including the nucleus, mitochondria, the endoplasmic reticulum), and their cytoskeletal systems are quite simple. These critters' genes do not have introns (aka junk DNA) and their genome does not undergo much recombination. If prokaryotes had a…