Monday, September 16, 2013

Of Chickens and Viruses

If you live in the US, you most likely have two egg-color options at your grocery store or farmers' market: white or brown. The color of these eggs doesn't affect flavor or nutritional content of the eggs - it just depends on the breed of chicken that layed them. However, if you have a Araucana, Dongxiang, or Lushi chicken (and if you do, you probably don't live in North America) they will probably lay blue eggs. A recent study in PLoS Genetics has shown that the reason for this is a retrovirus, EAV-HP, that has affected the chicken and turned it's eggs blue. But how can a virus affect eggs color?

The answer lies in how retroviruses work. Retroviruses use RNA as their genetic material (instead of DNA like we do). However, when the virus infects a host cell, it uses an enzyme called Reverse Transcriptase to translate it's RNA genome into DNA. This DNA is then inserted into the host cells' DNA genome, essentially tricking the host cell into using the information in the new DNA to make more retroviruses. The most famous retrovirus that affects humans is probably the Human Immunodeficiency Virus, shown in the image above (green) infecting a human lymphocyte (pink). Sometimes, when a retrovirus inserts a gene into the host DNA, it can change or affect the expression of genes around the insertion point. This is what happened with the blue egg-laying chickens.

In the case of EAV-HP, the virus inserted near a gene for a membrane transporter called SLCO1B3 and turned it on in the chicken uterus. This change allows the developing eggs to take up a bile pigment called biliverden from the chicken's body, turning the egg blue. Because this gene became part of the chicken's DNA, it is able to pass on the trait to it's offspring. Due to preferential breeding of Araucana, Dongxiang, or Lushi chickens that have this trait, most chickens of these breeds now lay blue eggs. The exact DNA sequences near theSLCO1B3 genes in these breeds is different, suggesting that the retrovirus caused the DNA changes that result in blue eggs in independent events in all three breeds. Both the blue pigment and the retrovirus involved are completely harmless to humans, so if you see a blue egg, don't hesitate to fry it up and enjoy!

(via BoingBoing)
(Image: Human Immunodeficiency Virus (HIV-I), a Creative Commons 2.0-licenses image from Microbe World's photostream)

Wednesday, August 21, 2013

Happy lobster month!

I'm not sure how this has not come to my attention sooner, but August is Maine Lobster Month! Lobsters are, by my estimation, the tastiest arthropods. Maybe some people would disagree.

When you picture a delicious lobster, ready to eat, it's bright red in color. On the other hand, if you've ever fished one out of the ocean (or seen it done) you know that live lobsters aren't that color at all - they're generally brownish. In honor of lobster month, here is an interesting video about why lobsters turn bright red when you cook them. Enjoy!

Bonus fact: Lobsters are colorful in another way - they have blue blood (like spiders and some other crustaceans), thanks to hemocyanin, a protein that transports oxygen in their blood using copper. Our blood and the blood of many other vertebrates is red because of hemoglobin, which uses iron to transport oxygen.

(Thanks to Life Lines blog for the link!)

Thursday, July 11, 2013

2013: The Year of Quinoa

Have you heard of quinoa? If you're one of the millions that shops at specialty groceries like Trader Joe's or Whole Foods, you probably have. It's an ancient grain, grown mainly in South America, which has become quite trendy in the us in recent years, and as a result has gotten more expensive. Can we expect the price to go down as the quinoa supply increases to meet rising demand? Maybe, and maybe not.

An interesting post at the Washington Post Wonkblog (with graphs!) gets into the economic reasons why quinoa farmers are not cropping up all over the world. Mostly, there is an enormous startup cost to growing a new species of plant on a large scale, or in a new environment. Producing more quinoa in the US, for example, would require both. Getting more quinoa from the farmers in Bolivia and Peru that have been growing the grain for centuries isn't such an easy proposition, either, as these traditional farmers use older techniques and equipment that are not so easily scaled up as are industrial agricultural methods. A number of solutions are being studied, including new varieties of quinoa that can grow in different climates. These topics will be discussed at an upcoming quinoa symposium.

Why are we eating so much quinoa? Well, aside from the facts that we love novelty the latest health food fad, quinoa is tasty and actually healthy. It's about 14% protein, which is a lot for something we consider a grain (although not as high as beans), and it is a vegetarian source of "complete protein," meaning that it contains all the amino acids that our body cannot synthesize on its own and needs to get from our diet. It's also high in fiber and a number of other nutrients like B vitamins and iron. So, eat your quinoa, if you can afford it, and hope that in the future, there will be enough to go around.

Also, here is a fun quinoa bonus fact from Wikipedia: While quinoa is not a true grass like the cereal crops we think of as grains (wheat, rice, etc.), it is closely related to tumbleweeds.

A tip of the hat to Ragan for the article!
(Image: Quinoa, a Creative Commons 2.0 licensed image from Renee S. Suen's Photostream)

Saturday, February 23, 2013

Science of Addiction: Junk Food Edition

Everybody knows that we shouldn't eat so much processed junk food, and everybody also knows that's it's sometimes difficult to control your intake of these foods. However, I don't think that many people have thought about what goes on in your brain when you eat many more potato chips than you had planned to eat. In the NYT this week there  is a very interesting piece addressing just these issues and the research that has contributed to our current understanding of why humans love junk food.

For the past 50 years or so, a great deal of research has gone into what it is that humans like to eat and how to market it to them, beginning with military research into which MREs soldiers prefer and continuing to the modern day with research into how many pounds per square inch of pressure it takes to break the ideal potato chip and how to successfully market baby carrots as snack food. Most of this research has been done by large processed food companies with an eye to idealizing the taste of their snack foods so that people will eat more of them. By most accounts, they have been wildly successful - so successful that in the U.S. today one in three adults is obese and the rate of type II diabetes climbs  every year.

One interesting tidbit from the article is that research shows that, although we like strong or unique tasting foods for a short time, we quickly tire of them if we eat the same one over and over again. Over the long term, we will eat more of relatively bland but tasty foods (like white bread and potato chips). This is great news for the makers of salty, fatty, but unremarkable snack foods (I'm looking at you, Cheetos!) that we know so well.

There is a growing awareness that the types of foods, especially processed foods, that people eat contributes to (or detracts from) their health as much, if not more, than the quantity of that food. As I learned from this article, even people involved with marketing processed foods to the public are acknowledging that what we eat is part of the growing health crisis in our country.

Hopefully in the future we can put all of the research behind marketing and idealizing unhealthy food to work helping people to make better choices about what they eat. The more we understand about why people like certain foods, the more we can make healthy foods that people like to eat, or at least stop making and eating addictive foods that ultimately make us sick. The solution to the problem will have to be a combination of information that consumers can use to make better food choices and more responsible food manufacturing and marketing by the handful of companies that control the majority of processed food in America. Understanding what is going wrong now is the first step in the right direction.

(Image: Junk food, grocery store, Houston, TX, USA, a Creative Commons 2.0 licensed image from Cory Doctorow's Photostream via BoingBoing)

Thursday, December 6, 2012

What is the future of agriculture?

This week I came upon two very different articles online regarding where our food comes from. They both focus on how technology has impacted the way we farm, but come to different conclusions about the benefits of current farming technology. I think they raise some interesting questions about what role technology should play in food production in the future.

The first article, on, discusses an art project conducted by photographer David Liittschwager, wherein he photographed all the species that pass through a cubic foot of area in different locations around the world. The result is a unique way of visualizing an area's biodiversity. Locations such as a public park in South Africa and a tree in Costa Rica contained more than a hundred different species of plants, insects, and animals. He also examined a typical Iowa cornfield - part of a huge system of industrial monoculture that provides much of our country's food supply. How many species did he find there? Eight. Including the corn. Over two nights and three days of observation, he didn't even find a single bee.

This total lack of biodiversity strongly contrasts the previous state of the Iowa prairie landscape, where a century ago hundreds of species coexisted in a complex system. Liittschwager's work raises questions about the benefit of our industrial agricultural system. What are we losing when we eliminate almost all species in a natural ecosystem? To what extent does the health of the soil and the crops depend on the complex network of interrelationships that we have destroyed without fully understanding? Industrial agriculture on this scale requires energy input in the form of fertilizer produced by burning fossil fuels. How long can we sustain these practices before we run out of materials or permanently alter our atmosphere and climate?

Another perspective on technology and farming comes from, where you can find photographs by Freya Najade of another technology-dependent method of food production: self-contained robotic farms. These facilities can produce food, without soil or sunlight, separate from any natural ecosystem. They are touted as possible models for production of food on the moon or in space, and similar systems have been developed to grow food in urban spaces previously considered unusable for food production. These systems, like the industrial corn farm mentioned earlier, feature a stark lack of biodiversity, but instead of destroying an existing ecosystem to create these farms, unfarmable areas have instead been transformed into a place where food is produced. Using computer-controlled systems, food can be grown locally, closer to consumers, and with less effort by humans, increasing efficiency. However, we don't fully understand the consequences of using these systems, which exist completely outside the natural environment or season, and which require the input of energy in the form of electricity and heat to function.

So, where do we go from here? What will be the role of technology in the future of food production? We have already used technology to enormously increase the efficiency of food production, with mixed results. The US spends, per capita, the least on food and the most on health care compared to almost any other industrialized nation. Industrial agriculture is changing our climate and eliminating biodiversity in our environment. Currently, the way we produce food is efficient but destroys our health and local ecosystems. Some proponents of systems such as biodynamic agriculture say that going back to a method of farming where we avoid monoculture and grow a diversity of plants on smaller farms that also include uncultivated natural spaces is the way forward. Could we also use more advanced technology to grow food outside of natural systems, farming previously unfarmable areas with the help of computers and other advanced technology. Can technology allow us to farm more efficiently, with fewer people, and closer to the consumers of food? I suspect that both of these approaches will be tested in the no-so-distant future, as we try to address the complicated problems with our current systems of food production. It may be that the best solution is a synthesis of old wisdom about how to care for plants and the soil and new knowledge of how to manipulate energy, information, and plant biology.

(Image: hydroponic farm 035, a Creative Commons 2.0 licensed image from missdrummajorette's photostream)

Sunday, November 11, 2012

DIY Sriracha

Hello internet friends, I know it's been awhile since I have last posted. The situation is, I've relocated from NYC to SoCal, and I've been busy moving and re-acclimating. So far, sunny California has been treating me well. It's almost impossible to find a good slice of pizza but the burgers and beer are pretty amazing.

I'm going to make an effort to get back to posting on a more regular basis soon. For now, please enjoy this awesome video about making your own Sriracha from SkeeterNYC that I found on BoingBoing.


If you don't know what Sriracha is, please read this informative comic from The Oatmeal.

Thursday, September 13, 2012

Old is gold...

I rarely talk about materials science on this blog, but today is your lucky day if you get excited about the physical properties of matter. As it turns out, all glass baking items are not created equal, because all types of glass are not created equal. A report in the Bulletin of the American Ceramic Society (also covered in this Scientific American Podcast) reports on changes in the material that Pyrex glassware is made from that affects its performance.

Prior to 1994, all Pyrex cookware was made of borosilicate glass (which is also what most laboratory glassware is made from). The advantage of this type of glass over normal glass is that it has a low coefficient of thermal expansion. This means that when the glass is heated, it expands less than normal glass. This might seem insignificant, but it can be important if the glass is going to be used in a way that results in it being rapidly headed or cooled, such as going from an oven to a refrigerator. Rapid changes in temperature can cause glass to expand unevenly, causing stress within the glass that leads to cracks or even breakage. Glass with a lower coefficient of thermal expansion is less likely to crack or shatter after exposure to rapid changes in temperature, making it ideal for kitchen (or laboratory) use.

However, since 1994, Corning has been licensing the Pyrex name to companies that produce products made of soda lime silicate glass, which is the type of glass found in most common glass items in your home. This glass is less likely to break when dropped (although this is not tested in the above bulletin), but has a coefficient of thermal expansion that is about three times that of borosilicate glass, making it more likely to shatter when exposed to thermal stress. In fact, the report says that a temperature change of 100 degrees F is enough to break the new Pyrex products, while a change of 330 degrees F was required to break the old borosilicate products. To put this in perspective, the difference between a raw, room-temperature roast and a hot oven is about 275 degrees F.

The take home message is that if you want the old, shatter-resistant formulation of Pyrex, look for older pieces (or, presumably, look for items that are labeled as being made from borosilicate glass). That casserole dish from the thrift store might be an even better deal than you previously thought. And, if you're a fan of pictures of glass shattering, definitely check out the full report from the ACS bulletin above!

(via BoingBoing)

(Image: IMG_5201, a Creative Commons 2.0 licensed image from gruntusk's photosream)