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August 12, 2006

~What's my secret? Frankly, dear, forgive my candor! / Family secret, all to do with herbs! / Things like being careful with the corriander, / that's what makes the gravy grander!~

Centrosomal RNA

Many years ago, Lynn Margulis (famous for her theory of the endosymbiotic origin of mitochondria) proposed that centrosomes originated from the fusion of a spirochaete-like-organism (right, image of a spirochaete) and the prototypical eukaryotic cell. The spirochaete may have helped the host cell to move around (I never found this explanation very satisfying - the spirochaete must have offered some other benefit). In support of this idea, various publications since the 50s claimed that the centrosome contained its own nucleic acid, just like mitochondria, but these experiments were never definitive.

The new paper.

Now out of Bob Palazzo's lab (no relation ... see extra comment at the end) comes a truly remarkable finding. His group purified centrosomes from clam oocytes ... for some reason clams have huge centrosomes and thus makes this experiment a whole lot easier. Along with the purified centrosomes came ... certain specific RNAs. (But wait, people have claimed this in the past, and one of the enriched RNA was 18s ribosomal RNA, so perhaps this mRNA was contamination?) What makes this finding believable is that only certain RNAs (five in this paper) were enriched. Besides the 18s rRNA, the other four RNAs were not found in any genomic database. (For you RNA enthusiasts these RNAs have now been called cnRNAs - centrosomal RNAs.)

And one of these cnRNAs is QUITE intriguing. It encodes a protein that has similarity to 'RNA-dependent nucleotide polymerase'. Furthermore, this RNA probably gets translated into protein. (Warning: technical jargon coming up) The group made antibodies against a peptide derived from the hypothetical protein, and found an immunoreactive band in lysates from oocytes and adult clam (end jargon).

So let me rephrase this. Clam centrosomes contain RNAs not found in any genome (so far), and one of these RNAs encodes an enzyme that could potentially copy RNA? Holly replication, Batman!

Sondheim is forcing Johnny Depp to audition for Sweeney Todd in order to prove his voice. via

Tim Burton, the London-based director behind the proposed film, has been praising Depp’s singing voice, but Sondheim needs to be convinced. The composer has said that he will not approve a cinematic version of his Broadway musical, which he describes as “virtually an opera”, if the main character has to mime rather than sing.

People are still sneaking water aboard planes with trusty Nalgene bottles. via

So, I managed to get on a plane this morning while "accidentally" carrying a potent solution of 100% dihydrogen monoxide in a Nalgene bottle.

So, the screening seemed to be pretty much useless. I had first emptied out the bottle for purposes of going through the X-ray machine, just in case they were anal about it--although I've heard that X-ray machines can't "see" liquid anyway, so perhaps this doesn't matter. The empty bottle passed through with no complaints. Nobody seemed to be getting hand-searched either.

Okay, so now what?

Next, the TSA has these great signs posted directly at the gates (and at all of the food establishments) which state that all beverages need to be discarded before boarding the aircraft... even your fancy venti blended-no-foam crapuchino, but there did not appear to be any secondary screening. People still board planes as usual, which means that you wave a piece of paper at the scanner and it lets you onboard.

So, I carefully refueled my dihydrogen monoxide at the fueling station in the airport, and I was merrily able to go on my way.

If the X-ray can't really detect liquid, then this is presumably a big problem. (If it can, then I guess this is no different than the "someone smuggled a knife into the magazine store and then I picked it up" threat model.)

PS: http://www.dhmo.org/

Posted by: SD at August 11, 2006 04:05 PM

Back in the 1940s, Popular Science had fun chemistry articles for kids like "Learn About SULPHURIC ACID":

Concentrated acid is made commercially by the “contact” process in which sulphur dioxide, produced by burning sulphur or roasting iron pyrites, is passed over a heated catalyst, which causes it to combine with oxygen of the air to form sulphur trioxide. Since the finely divided sulphur trioxide cannot be dissolved directly in water, it is added to concentrated sulphuric acid, forming a superconcentrated or “fuming” acid which is easily diluted to the required strength.

You may demonstrate this “contact” process in your kitchen laboratory, with the simple apparatus shown. Your sulphur dioxide producer is a tin-can cover on which you burn a few grams of flowers of sulphur. This gas is collected by an inverted funnel held just high enough for air to come under its rim. Tubing carries the sulphur dioxide to the bottom of a pickle jar filled with lumps of calcium chloride which filter and dry it. For a catalyst, moisten a little asbestos fiber and shake it with a quarter of its bulk of iron oxide. When thoroughly mixed, dry in an oven and pack loosely in the glass tube which is arranged horizontally in your setup. The remaining flask contains concentrated sulphuric acid. The half-gallon jar is a siphon bottle which draws the gas through.

The Bunsen burner must be adjusted for gentle heat or the sulphur trioxide will decompose again. A marked increase in the concentration of the sulphuric acid in the flask occurs in a few minutes. By adding it to water—in diluting, always pour the acid into the water—you get a greater quantity of acid of the original strength.

Sulphuric acid is used in making many other acids. As an example, nitric acid— tremendously important in manufacturing explosives and cellulose films—may be made in your home laboratory, but use a glass retort as nitric acid reacts on cork and rubber.

Posted by Jon Rubin at August 12, 2006 11:09 PM

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Posted by: Melinda at January 16, 2007 01:27 AM

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