Friday, June 10, 2005

Fungus kills mosquitoes

This is pretty exciting:
In a finding that may open promising new ways to attack malaria, scientists are reporting today that two fungi that are harmless to humans and the environment can be used to kill mosquitoes.

The fungi are already licensed in Western countries to control aphids, termites and other pests, according to two studies in the journal Science. One of the researchers, Dr. Matt B. Thomas, a biologist at Imperial College in London, estimated that a "deliverable product" could be ready in three to five years, if he could get money for further research.

Malaria kills more than one million people a year, mostly children under 5 and pregnant women, especially in Africa. Despite the advent of new drugs and better mosquito nets, some specialists say deaths may be increasing, largely because of bureaucratic delays among donors and breakdowns in African public health systems.

Moreover, mosquitoes eventually develop resistance to every chemical pesticide used on them, including DDT. No resistance to fatal fungi has been reported among agricultural pests, Dr. Thomas said.
The fungus wouldn't be sprayed indiscriminately, but rather on bednets and indoor walls. This works because, in Africa at least, mosquitoes typically bite people inside while they're sleeping, and they have to rest for at least 6 hours indoors after a blood meal before they go outside to lay eggs - so while they're resting, they get exposed to this toxic fungus and get weakened, and eventually die after a couple weeks. So even if this fungus turns out to have some unexpected bad effects (which I'm sure it will), they will be limited by the limited spraying. (No vast spraying of farms with DDT here!)

And even if there were some toxic effects on either humans or some ecologically important insect - I think that price is worth paying (to a certain extent, of course, but a significantly non-zero extent) if we can significantly reduce the burden of malaria. Remember, it's not just that poverty causes disease - it's also that disease causes poverty.

Tuesday, June 07, 2005


This is the most offensive thing I've seen in a long time:
Zoo organizers in the southern German city of Augsburg have come up with the idea of putting Africans on display at their zoo as an uncoventional way to attract more visitors. That's right. They want to create a living "African Village" featuring African basket weavers, woodworkers and storytellers posed among huts located near other African inhabitants, like elephants and rhinos. The idea is to let visitors gawk at -- or as their brochure says -- "discover the Dark Continent." Plans for the show -- scheduled to open July 9 -- have engendered outrage from Africans and civil rights advocates across Europe, but particularly those in Germany. Historian Norbert Finzsch, provost of the University of Cologne, too, has lambasted the project, insisting it underscores that in Germany "people of color are still seen as exotic objects (of desire), as basically dehumanized entities within the realm of animals." Finzsch insists the idea to hold such a display is "the direct result of 40 years of German colonialism and 12 years of National Socialism.

Zoo organizers seem to be painfully oblivious to their insensitivity and claim to be at a loss to understand the commotion. For instance, in a written reply to a Swiss African protestor, zoo director Barbara Jantschke, insisted that the idea was not to offend people. Instead, she said, the zoo is "exactly the right place to convey an exotic atmosphere." Nor could she understand the brouhaha, after all, one of the organizers is himself "a native African with black skin." Ever heard of sensitivity training?
I cannot believe that the quote-unquote "show" is still scheduled to go ahead. I don't know whether to be more offended if Barbara Jantschke is sincerely puzzled or if she's being disingenuous.

[Via Foreign Dispatches.]

Update, 9 June: I tried to find information about this event on the Augsburg Zoo's webpage, but since I don't read German, that didn't work. Thanks to American Amnesia, I see that this is the page. So, in fact, the "African Village" exhibition is going on as we speak! (I guess the Spiegel story might have mixed up June with July...) By the way, if you feel like complaining to Barbara Jantschke, her e-mail is

Monday, June 06, 2005

Insane Ravel

I've been trying to learn Ravel's Miroirs, a suite of pieces for the piano. I've started working on the third piece in the set, "Une barque sur l'ocean" (A boat on the ocean). It's absolutely beautiful, but very difficult. Now, the technically difficult bits I can handle, though it will take some suffering and a lot of work - but to add insult to injury (literally - there's a painful glissando over black keys and an awkward figure in the right hand that threatens to give me tendinitis), Ravel actually writes in a note that doesn't exist on the piano! (The G# below the lowest A.) What is he, crazy?

Road pricing and slippery slopes

So I heard on the radio this morning that the British government is going to start trials of road pricing, where car drivers will be taxed for every mile they drive, at a rate that varies with how busy the road is. So a busy street in central London during rush hour could be taxed at up to £1.34/mile, while a deserted rural road would be taxed at only 2p/mile. The idea is to give people incentives to avoid using the most congested roads, to avoid total gridlock in years to come. (This is in contrast to gas taxes, which gives people incentives to drive less and use more energy-efficient cars, but still allows them to drive in congestion-producing patterns.)

It seems like a good idea, at least in theory, though I think it shouldn't replace the gas tax. But I'm very concerned about the so-called Big Brother objection - the government will know where your car is at all times, because without that knowledge, there's no way to tax you accurately on road usage. (You might have to install a GPS bos on your dashboard, to be read by satellites, or video cameras could snap pictures of your license plate as you drive by.) That's really quite creepy. And not only could a government abuse such knowledge, but criminals could hack into the road usage databases and track down people's cars (e.g., if a mobster wanted to assassinate someone). Now, I'm sure we could design ways to prevent abuse of the database, but once the enforcement infrastructure is set up, it will become much easier for the government to use the information for civil-liberties-destroying purposes. This is what Eugene Volokh calls a cost-lowering slippery slope.

All in all, I think road pricing is too intrusive. Better to use more traditional methods like tollbooths and London's congestion charge.

Friday, June 03, 2005

Genetics and sexual orientation in fruit flies

So neuroscientists have made lesbian flies. Well, sort of. NYTimes story here, actual articles here and here (back-to-back articles in the prestigious journal Cell - you probably need a subscription to access the full text). Quick summary:
[One gene], the researchers are announcing today in the journal Cell, is apparently by itself enough to create patterns of sexual behavior - a kind of master sexual gene that normally exists in two distinct male and female variants.

In a series of experiments, the researchers found that females given the male variant of the gene acted exactly like males in courtship, madly pursuing other females. Males that were artificially given the female version of the gene became more passive and turned their sexual attention to other males.
As always, the NYTimes write-up makes a little bit too much of the study. In particular, it says that "The finding supports scientific evidence accumulating over the past decade that sexual orientation may be innately programmed into the brains of men and women." Um, these studies were done in fruit flies. It hardly seems that it should be necessary to point out that fruit flies have much simpler nervous systems than humans and are much less capable of complex behaviors and learning. I don't want to put up humans on a separate plane from animals - we are animals, still, and human sexual orientation does have an innate component - but it is really stretching the absurd to infer the genetics of sexual orientation in humans from fruit flies. (David Velleman makes a similar point.)

The significance of this study has nothing to do with whether homosexuality is innate in humans or not, but lies rather in the novel demonstration that a single gene switch can control a stereotyped behavior through the development of a neural circuit, in the same way that a single gene switch can control the development of body parts (the analogy is to the fly gene eyeless, which is necessary and sufficient for eye formation).

One of the funny things about the NYTimes article is that it depicts the scientists as shocked and disbelieving, e.g. "The observing scientist looked with disbelief at the show, for the suitor in this case was not a male, but a female that researchers had artificially endowed with a single male-type gene." In fact, this result is pretty well expected, and I imagine that the experimentor was looking on not with disbelief, but rather a sigh of relief that the experiment worked and the hypothesis was confirmed.

The "fruitless" hypothesis of male courtship in the fruit fly was proposed almost 10 years ago. See here (under "Biological Overview") for a nice, if technical, summary of how the gene fruitless was thought to control male courtship behavior. Basically, the gene fruitless can encode several different protein products depending on how the message is processed (alternative mRNA splicing), and males and females produce different protein products. These fruitless protein products are transcription factors that then go on to control the expression of other genes, ultimately leading to differences in neural circuitry and hence behavior. So this latest result is not that surprising in its essence - what's surprising is how clean the result was and how completely fruitless controls courtship behavior.

Even so, the results weren't quite as clean as the NYTimes made them out to be. Females expressing the male variant of fruitless carried out most of the male courtship ritual, but spent less time licking tthe court-ee than wild-type males did. They also spent less time courting than wild-type males did during the 8 minute assay (40% v. 90% - though this difference could be due to the fact that the assay ended when males succeeded in copulating, which was obviously impossible for the mutant females). But this is just details - overall, the result is really remarkably clean.

One final point: one interesting facet of the second study is that males and females don't have many obvious anatomical differences in the neural circuitry that is controlled by fruitless. I'll quote the article:
We do not think it is their gross anatomy. With the trivial exception of neurons innervating the reproductive organs, we detect only subtle differences in the numbers of these neurons and no differences at all in their morphologies or projections. Pending further studies at higher resolution, we tentatively conclude that sex differences in courtship behavior do not rest on differences in the production, survival, or connectivity of the neurons involved.

This conclusion offers a rather sobering perspective on the considerable effort that continues to be devoted to identifying and characterizing sexual dimorphisms in the mammalian brain. In Drosophila, the sexual behaviors of males and females are dramatically different and highly stereotyped; we can attribute this difference to a single splicing event in a single gene, and we can examine the neurons that express this gene at single-cell resolution. Yet even under these ideal circumstances, we still cannot find any anatomical differences that might account for the dramatically different sexual behaviors of males and females. This suggests that differences in neural chemistry, rather than gross neuroanatomy, might underlie the profound differences in behavior between males and females in Drosophila, and surely in many other species as well.
In a way, I'd have been disappointed if it was the gross neuroanatomy instead of subtle molecular and cellular differences. The fantastic complexity of the brain at every level of analysis from anatomy to molecules - even in the simple fly - is maddening at times, but it's what makes neuroscience such an interesting field to be in at the moment.

Wednesday, June 01, 2005

Vaccines aren't just for children

An effective shingles vaccine has been developed. Hooray!