Helen FieldsScience Writer

Last weekend I wrote a blog post for ScienceNOW about whether “test tube” babies are healthy. Answer: Basically, yes, but the oldest one is only 31, so there’s no way to know about health effects that show up later in life. And there are definitely differences between babies conceived in vitro and babies conceived the natural way. The differences are epigenetic, which means they’re not differences in the genes themselves – they’re related to how the genes get expressed.

This is related to a shift in how people think about biology. For decades after DNA was discovered, everyone was really worked up about the genetic code, and how genes are a blueprint for everything. But the truth is, of course, much more complicated. Just because you have a gene doesn’t mean that it’s being expressed. It might be turned off entirely, or only weakly expressed, or only expressed in some cells and not others. Epigenetics is about looking at differences in how genes are expressed (turned into proteins).

You can understand the blog post even if that doesn’t make sense

Fun fact: They aren’t test tube babies, they’re actually petri dish babies.

Another fun fact: The picture with my story is of an egg being fertilized by intracytoplasmic sperm injection (ICSI) (”icksee”). While in vitro fertilization was developed to get around female infertility, ICSI is for male infertility. As long as the guy is still making some sperm, you can fish them out and inject one right into the egg.

Yesterday I went to a session at the AAAS meeting about the links between music, language, and the brain. I was particularly impressed by a study on Musical Intonation Therapy. Sometimes people who have had their speech knocked out by a stroke can still sing; this therapy is based on that idea. Patients are trained to speak by singing.

I wrote a blog post for ScienceNOW about a study on whether (and how) this therapy works. I was amazed by the video I describe in the beginning of the story. Unfortunately, the researcher doesn’t have permission from patients to spread video widely, just to show it in presentations.

The researcher said a stumbling block for using this therapy is that people are embarrassed to sing. I think that’s sad – not just because it seems to be a useful therapy, but also because I wish singing was more routine in our culture. Once the therapists – and patients – get over that, the therapy seems to work well.

There was lots of neat stuff in the session. Here’s someone else’s story about how learning an instrument helps with language skills, and here’s a BBC story about the stroke research – be sure to listen to the audio file. (It’s linked a few lines below the picture.)

I started the AAAS meeting right Friday morning by going to a session on the science of superheroes. A couple of scientists were joined by two writers from the TV show Heroes and one of the screenwriters on the movie Watchmen. I was really interested in what they had to say about their work, both as a person who likes science and as a writer. They talked about scientific accuracy and how they do what they do. The upshot was: They care about science, but ultimately the character and the narrative are what they care about most.

I wrote about the science of superheroes for ScienceNOW and also did an interview for their podcast with a scientist who has written about physics in comic books.

I’d watched season 1 of Heroes, so I was able to give a little background about the show in my blog post. But then I had a great quote about Watchmen, but no idea what the guy was talking about. So I put out a call on facebook for any friend who knew Watchmen really well. I had five or six offers of help within 10 minutes. Thanks for the help, crowd!

The Science Channel posted more quizzes!

1. Bones. I put in a Harry Potter question. Oh yes I did.

2. Wind Energy. It’s free, it’s windy, it’s wind energy. Includes a question based on a book I was supposed to read in eighth grade. I was a really good kid, but I don’t think I ever finished this book.

3. Fossil Fuels. Do you know why they’re called that? Eh? Do you? Take the quiz!

To see all my quizzes, click here.

The Science Channel has posted three more of my quizzes! Woohoo! Tell all your friends!

You may do better on the Science of Alcohol quiz if you know your Elizabethan poets.

I got certified for Scuba in 1995. I haven’t been on a dive since 1996. It was on the Great Barrier Reef. It may have spoiled me.

If you went scuba diving, you might see Coral, which, ohmygosh, is the subject of the last quiz.

To see all my quizzes, click here.

Yesterday for ScienceNOW I wrote about tobacco plants that open their flowers at a different time of day if they’re getting eaten by caterpillars. (My story.)

It’s kind of ingenious, if these scientists are right about it. Hawkmoths are good for the tobacco plants, because they pollinate them. Plants want pollination. But female hawkmoths also lay their eggs on the tobacco leaves. Eggs hatch into caterpillars that eat everything in sight.

So if there are caterpillars around, this study shows, these plants shift their flowering from night – when moths are out – to morning, when hummingbirds are awake.

Plants have a ton of ways of dealing with predators. They can produce toxins to hurt the predators. They can stop making new leaves, send new sugars to their roots, and wait until the predators go away. My favorite: They can send out “heelllp meee” chemical signals to attract their predators’ predators, like a parasitic wasp that lays its own eggs in the caterpillar.

One of the guys I talked to for this story told me (when I interviewed him for another story) that he used to be able to tell what species of caterpillar was eating a plant in his lab by the smell of the chemicals the plant was giving off. They’re that specific.

Plants are awesome.

photo: Danny Kessler

Why do mosquitoes buzz in people’s ears? I actually can’t remember the conclusion of that children’s book, but I can now tell you a bunch more about mosquitoes buzzing in general. It’s in this ScienceNOW story. Enjoy.

For the study, the researchers recorded the sound mosquitoes’ wings make. They needed the mosquitoes to fly in place. The paper just said the mosquitoes were tethered, so of course I had to ask how.

So, in case you ever need to know how to put a mosquito on a leash, here’s an excerpt from my interview notes with Gabriella Gibson, who’s been studying mosquitoes for 30 years:

“You warm up a wire with something like a soldering iron – a very thin wire with a little loop on it. You dip it in some melted beeswax, and you dip it on the back of the mosquito, which you keep cold by slopping it on a block of ice, and then it just sort of melts onto the back of the mosquito. About a minute later, it’s fine and flying away. You can stop it from flying and keep them kind of calm by just putting a piece of tissue paper touching their legs. If their legs let go, they start flapping their wings. We had a little rig so we could lower them down so they could rest a bit. We could give them a little piece of cotton with a piece of sugar water – they stick their feeding parts into it.”

Then she told me she once used a fine piece of silk thread instead of a wire and took a mosquito for a walk. (It flew, she walked.) I’m not sure if there was a scientific reason for that or if it was recreational. Anyway: this is someone who knows how to handle a mosquito.

I don’t know how you have fun at your house, but I celebrated Christmas Eve with a story about tooth decay for ScienceNOW. (Ok, I wrote it on the 23rd; it just went through final editing on the 24th.)

The thinking on tooth decay has changed a lot in the last few decades. The people who study oral health used to focus on one organism, Streptococcus mutans, as the culprit in cavities, churning out the acid that destroys enamel.

But now they realize that tons of microbes, from hundreds of species, live in your mouth. Your mouth is like a tropical rainforest, but with Streptococcus and Bifidobacterium and Lactobacillus instead of fig trees and monkeys and toucans. People who study dental disease – and intestinal disease, too – have realized they need to think about the mouth and gut like an ecological system.

The advances in molecular biology in the last couple decades have totally revolutionized the study of microorganisms. In the old days, if you wanted to know what was growing in someone’s mouth, you had to take a sample of goo, then grow it up in the lab to see what you had. The problem is, a lot of bacteria are hard to culture. They’re finicky eaters. Some won’t grow in the presence of oxygen. But now, scientists can take that goo, extract DNA, and census the bugs without having to culture them.

That means scientists are getting more of a handle on all the different jungles in your body. You are so majorly outnumbered by bacteria. There’s one of you and a bazillion of them. They live in your intestines, in your nose, in your mouth, on your skin. You’re even outnumbered at the cell level. There are more bacterial cells in and on your body than human cells. Don’t worry, you’re still mostly human if you measure by volume; bacterial cells are much, much smaller than mammal cells.

Photo: Bifidobacterium dentium, courtesy of the Ventura Lab

Fruit flies may all look the same to you. But not to other fruit flies! A new study in the journal PLoS Biology finds that males prefer bigger females. In fact, they harass the big girls so much, those females don’t lay as many eggs as they would if the darn males left them alone.

My story about sexy fruit flies appears today on ScienceNOW. I must warn you that it includes fruit fly porn.

Approximate conversation with editor yesterday afternoon: “I was thinking of taking out the second to last paragraph. I think it’ll flow better.” Me: “I don’t really care, as long as my ‘hitting on the hotties’ joke stays in.” Editor: “Well, at least you’ve got your priorities straight.” Ok, ok, I care how the story flows. I just trust the editor to make the right decisions – he can take out whatever he wants, if he thinks it improves the story. Although he also took out that joke. Ah, well. You win some, you lose some. Important writing lesson: It’s easier for an editor to remove excess personality than to add personality.

I am pleased that a story with the title “I’m Too Sexy For My Species” appeared on my birthday.

photo: Tristan Long

In Bangladesh, millions of people drink contaminated water that’s contaminated with arsenic. This isn’t like in a mystery novel when someone gets poisoned with arsenic. You don’t keel over dead. Water with arsenic in it is lovely and clean and doesn’t need to be boiled – and in the long term, it increases cancer risk as much as smoking.

Today I wrote for ScienceNOW about a new study on arsenic in Bangladesh. Some researchers from MIT think they’ve figured out why some water has more arsenic than other water. Special microbes dissolve the arsenic from the sediment into the water, and they need a carbon source – so the scientists who study arsenic in Southeast Asia are arguing over where that carbon comes from. The new study gives one answer to that question. Read my story here.

In the meantime, people in Bangladesh need low-arsenic water. Filters work, but they’re expensive and need maintenance. Deeper wells tap into deeper aquifers with less arsenic, but they’re also expensive, and as water is sucked out of the deep aquifer, higher-arsenic water could sink down from above.

I thought it was fascinating that the people of Bangladesh have traded deaths from water-borne disease for long-term cancer risks, but I talked to an epidemiologist, Allan Smith at Berkeley, who figures it’s not worth arguing over which was worse. “For me, it’s not something I’ve ever cared to try to quantify. Clearly we want to reduce the deaths from gastroenteritis and clearly we want to reduce the deaths from arsenic. We should just move forward.”