Bullets: tongue biters, London crackheads, and the return to the moon
Woohoo bullets!
- NASA is going back to the moon. On paper, anyway. Probably most of you have heard about this by now, so I’m not going to do an extensive writeup on it. Ars has the best coverage, as usual, and New Scientist also has san article on it.
- A few days ago, I wrote about Cymothoa exigua, the tongue biters who strangle or eat (it’s still unclear) the tongues of their host fish, substituting themselves instead. But why stop at one tongue biter when you can have two? That page also has more pictures of normal fish tongues and other cutaway photos of the fish.
- Apparently one in every hundred Londoners could be a crack cocaine user. Sounds like they’ve got the same problem as Italy. Maybe Virgin should start a cocaine refinery: Virgin Coke.
On the subject of NASA returning to the moon… while this is nice to see, and the moon provides a good stepping stone on the way to Mars or a similar mission, I can’t help but feel just a little disappointed. While no one in my generation has ever seen anyone walk on the moon, we have seen the Apollo 11 video footage. My mom was 14 when Apollo 11 landed, and I’m 22 years old. It’s been decades since we’ve been to the moon, and now, all of a sudden, we’re going back and there’s this big to-do about it, as though something extraordinary is about to happen.
We were on the moon in the sixties. Almost 40 years ago. Why should we be excited to go back to a place we went to two to three generations ago? This is not new or spectacular. This is redundant. Unlike Halley’s Comet which comes around once every 75 years, and is constant, science and technology is fluid and always progressing. The moon is the best we can do, now, 51 years after we did it the first time? Please tell me I’m not the only one disappointed by this. Is a moon landing something that’s only going to happen once every 50 years, so we should simply get used to it and enjoy it while it’s here? Or are we going to make a decision to finally push beyond the bounds of Earth and keep going instead of throwing up our hands only to sit back complacent in the knowledge that we “did it” and there’s nothing more to be done?
I realize that the space race was a political tool more than anything else, and that it served its purpose (along with the nuclear arms buildup) in bankrupting the Soviet Union, but I would have expected a little more out of NASA than merely a plan to return to the moon 50 years after the first landing. If not NASA then a private corporation, though I suppose that (right now) there isn’t much money to be made in space simply because of the prohibitively high cost of transportation. Anyway, so is this return to the moon to accomplish some major political end, or is it finally in the interest of science? I don’t know the answer, but I hope it is the latter, because if it is, there’s actually a chance that we’ll stay there or even push on instead of returning to Earth once it’s “mission accomplished.”
The replacement tongue
This is so awesomely disgustingly great I had to post it. There’s a louse that consumes a fish’s tongue and replaces it with itself. Cymothoa exigua was discovered inside the mouth of a red snapper bought from a London market. The louse had grabbed ahold of the tongue and slowly eaten it away until only a stub was left. It then latched onto the stub and became the fish’s tongue — getting a free meal after having fed on the tongue artery while it ate away.
Naturally, some crazy scientists are excited by the find, while the rest of the world remains disgusted. I’m intrigued: it’s certainly a novel idea, and quite frankly, I’m surprised something like this hasn’t been discovered before. The fish most likely came from California, but there is some confusion. Cymothoa was known to exist in the Gulf of California, but since it showed up in London, they’re not sure whether the fish was imported or the louse is simply expanding its territory. Cymothoa poses no danger to humans since it only attaches to fish tongues. Found attached to Lutjanus guttatus (a red or rose-spotted snapper, depending who you read), the parasite poses no danger to humans, but is pretty disgusting.
It enters through the fish’s gills and uses claws to attach itself to the base of the snapper’s tongue and survives by drinking blood from an artery. Once the tongue has been gotten rid of, it attaches itself as a new tongue, and manipulate’s the fish’s food and consumes the free food particles as the fish eats. Again, there is some confusion on what exactly happens: whether the louse eats the tongue, or simply causes it to atrophy due to blood loss, but the net effect is the same: the louse becomes the new tongue.
Imagine dicing up a fish for dinner and seeing one of these little monstrosities, eh? (Another larger image)
From Practical Fishkeeping, Discovery, and CBBC News.
The problem of antibiotic resistance
I’ve had this article written for about two weeks now, and I’ve been holding onto it for a short time, but I’m not sure why. So here it is.
I cover the basics of antibiotics, how they work, why viruses and bacteria are different, why antiobiotic resistance is such a big problem, how it’s being dealt with by doctors and the pharmaceutical industry, and why this is relevant to you.
In the real world, even if a patient knows all these things when the see their doctors, it doesn’t necessarily help when they demand something that will make them feel better. Doctors have long felt the pressure to write prescriptions for antibiotics when the cause of the ailment is likely viral. This keeps the patients happy, but it is causing problems for the reasons I outlined above. Doctors know they’re digging a pharmaceutical hole by giving in to patient demands, but often appeasement is easier than sending a patient home unhappy without a prescription.
Come inside and check it out. Maybe you’ll reconsider asking for a prescription the next time you visit your doctor…
Bullets: armor-piercing shells, gluten, and transferred toxins
It’s time for another bullet roundup. Lots of cool stuff, but without enough substance to really create a real post about them. Nonetheless, they’re worth posting about.
- New shells that use a chemical reaction to burn through armor plating are on the horizon. Instead of using depleted uranium shells which are toxic to the environment, the new technique uses to chemicals, that, when mashed together, create tremendous heat almost instantly, burning through armor. I wonder what this hopes to accomplish, save burning a hole in something. Will there be some sort of anti-personnel round underneath, or will the reaction simply burn everyone to death instead?
- New advances when it comes to isolating the toxins that cause wheat gluten intolerance. One person out of 200 in the West is affected by gluten intolerance, which severely limits their diet. A person who is wheat gluten intolerant cannot eat pasta, cereal, bread, or many of the other staples that most people enjoy. By isolating the two aggravating types, this raises hopes that wheat products without these two toxins can be developed.
- Household toxins can be transferred across the placenta. This isn’t especially surprising, since most foreign substances cross the placenta but it’s worth mentioning in the light of Hurricane Katrina. Jonathan has a good writeup in this week’s Science.Ars that explains why toxins in battered New Orleans are as big a health issue as disease proliferation through dirty water. In the case of a fetus, these toxins, including plasticizers, can cause significant damage to a developing baby.
Regrowing hearts, lungs, but not brains
Researchers have recently found a way to cause mice to regrow and/or regenerate vital organs: hearts, lungs, appendages, etc. In fact, the only thing that they couldn’t get to regenerate was the brain. Normally, mammals cannot regrow limbs, once they’re lost (unlike certain reptiles), because the genes that control this ability are turned off by default. Ellen Heber-Katz of the Wistar Institute found that by manipulating about a dozen genes, this ability could be turned back on. The whole thing seems rather vague to me, for the simple reason that what genes and how many there were that were altered seems to be unknown. While the results are slated to be revealed this coming week, we’re left dangling in the meantime.
The self-healing mice, from a strain known as MRL, were then subjected to a series of surgical procedures. In one case the mice had their toes amputated — but the digits grew back, complete with joints.
In another test some of the tail was cut off, and this also regenerated. Then the researchers used a cryoprobe to freeze parts of the animals’ hearts, and watched them grow back again. A similar phenomenon was observed when the optic nerve was severed and the liver partially destroyed.
While direct analogs in the human genome are unknown at this point, this could potentially lead to much longer lifespans among humans. It’s almost mind-boggling to think about: imagine an injection of fetal liver cells that would allow an elderly person to have six months of regeneration. Bad hearts are made new, arthritic joins are repaired. I doubt it’s this easy in human beings, of course, so I will retain a modest amount of skepticism for the time being, but I do think that this sort of treatment offers a great deal of hope (somewhere) on the horizon.
What I would like to know is whether stem cell research is involved. If not, this would leapfrog a huge ethical barrier, at least here in the United States. Sadly, though, I suspect that there is, simply because of the phrase “fetal liver cells.” Unfortunately, this regeneration method doesn’t offer any hope for those who choose (or chose) to indulge in reckless recreational habits of questionable legality in the past or present.
Parasitic brainwashing and African sleeping sickness
The other day I was watching Smallville season 2 (hooray Netflix), and the next morning I read this story about parasitic hairworms “brainwashing” their grasshopper hosts, causing them to jump into water, effectively committing suicide. Anyway, the episode I was watching involved parasitic worms causing their human hosts to do crazy things. Go figure that I dismissed the idea as fun science fiction, only to read the next morning about the same thing happening in the insect world. (I shouldn’t have been surprised though, given the stupid things people do while cracked out on PCP.)
The parasitic Nematomorph hairworm (Spinochordodes tellinii) develops inside land-dwelling grasshoppers and crickets until the time comes for the worm to transform into an aquatic adult. Somehow mature hairworms brainwash their hosts into behaving in way they never usually would – causing them to seek out and plunge into water.
Once in the water the mature hairworms – which are three to four times longer that their hosts when extended – emerge and swim away to find a mate, leaving their host dead or dying in the water. David Biron, one of the study team at IRD in Montpellier, France, notes that other parasites can also manipulate their hosts’ behaviour: “‘Enslaver’ fungi make their insect hosts die perched in a position that favours the dispersal of spores by the wind, for example.”
Now scientists have worked out the mechanism by which these worms cause this mass suicide. The worms produce proteins which directly and indirectly affect the grasshopper’s central nervous system. (Video available; be warned, watching worms larger than their hosts look as though they’re being excreted from crickets and grasshoppers creeps me out.) While the explanation seems rather vague, it can be definitively be said that the grasshoppers and crickets and spiders are not in control of themselves when they take the plunge: they are not doing it willingly.
What’s even more interesting from a human point of view, is what this means for insect behavior and how it affects human beings. In the case of the Nematomorph worm, which starts out microscopic and grows to be larger than its host when it finally takes over, it causes the insect or spider to commit suicide. In the same vein, a parasitic organism like Trypanosoma may cause the host insect to have an increased appetite. This means that the vector — the tsetse fly in this case — may be more aggressive in feeding. This, in turn, can mean greater rates of infection because the odds of an infected tsetse fly biting are greater than those of a non-infected fly, which means more African sleeping sickness being spread.
DNA reassociation
I read reading New Scientist, and I found something new and cool to learn about: DNA reassociation.
It’s a technique for determining the number of different types of organisms in a given amount of material. What happens is that a chemical is added which causes the DNA double helix to “unzip,” leaving single strands of DNA. The single strands are mixed up with many other single strands of DNA, and the amount of time that it takes for the strands to find a match yields a rough estimate of how many distinct types of organisms are present in a given sample. The point of the actual article was to say that there are many more species of bacteria undergound than were previously thought. I just thought the DNA reassociation thing was much cooler.
When this technique was applied to soils in the late 1990s, it suggested that a gram of dirt contained about 16,000 species. But this estimate assumed that the populations of all the different species in the soil were roughly equal in size. So Gans and his colleagues have developed new equations to reanalyse the same DNA reassociation data but without this size assumption.
Their results reveal that there are a few very common species in soil but lots of rare species. “There is a very large number of low abundance species,” says Gans. So many rare species, in fact, that the estimate of bacterial biodiversity rises to one million species per gram of soil.
If you do an Internet search for “DNA reassociation” you’ll find lots of academic websites explaining the equations to describe rates of reassociation and how they relate to real world strand diversity in a given sample, but all of them (that I found) make an assumption about the size of the strand involved. I wonder how these new equations will alter the study of DNA reassociation kinetics?