Attack of the DNA robots

Whereas bombing raids in the early and mid part of the 20th century involved hardly any direction, any bombing that we do today is going to be highly precise. This so-called smart bombing has constituted one of the great military advances over the past several decades. It’s efficient, cost-effective, and saves civilian lives. Now keep that in mind as I move into the non-military world of fighting cancer.

In one form or another researchers have been working to create DNA carrying/laden devices for years now. The application potential is huge, but the area that has received some of the greatest focus has been cancer research. The drugs and treatments we have now are inexact and not always effective. Aside from often killing healthy cells, thus leading to weight and hair loss, general illness, and other negative side-effects, they don’t always kill every cancer cell. Even surgery can be a bad thing at times. Consider for a moment what tumors need. More than perhaps anything is a blood supply. (The same goes for your regular cells; your skin cells are too far from a blood source, hence why they are little more than dead keratin.) In order to get their supply of blood, tumors must induce angiogenesis, the growth of new blood vessels. They do this by releasing certain stimulators. They also release inhibitors, but not enough to overwhelm the stimulators. However, these inhibitors have no problem traveling through the blood stream. The result is often the suppression of secondary tumors, especially if they are nearby. So when a surgeon removes a primary tumor, those other, previously restricted secondary tumors will have a chance to grow. And that is no good, of course. In short, the more exact we can get in destroying cancerous cells, the better off we will be.

Enter DNA nanobots.

I like to think of these as smart bombs of cancer cells. They are bits and pieces of DNA naturally self-assembled into a particular shape (the barrel in the background) that is prepared to deliver a payload. That payload (the purple/pink stuff) is attached to specific strands (the yellow/green stuff) inside the DNA barrel structure. This is all held together by strands of DNA which are programmed to recognize specific molecules on the target cells (in this case, cancer cells). When the DNA attaches to these molecules, it changes shape and opens up the barrel. The payload is then free to enter into the target cell, inducing apoptosis (cellular suicide). Experiments have shown that these DNA robots are able to avoid healthy cells during this process.

There are, of course, limitations to this technology. Take malaria, for instance. It would be difficult to target most strains (such as P. vivax and P. falciparum) because they get inside hemoglobin rather than attach to the outside of anything. That makes them effectively invisible to both our immune system and these nanobots. Strategies for fighting that disease will tend towards the sort of medications we’re using now combined with bed nets and efforts to destroy mosquito habitats.

Still, this is exciting. I say that about most cancer-related advances, but I don’t feel I’m ever overdoing it. Every little bit of progress is crucial, even the bits that don’t pan out. I have hopes for this one, though. Even if it doesn’t end up being pragmatic in application, it still has the potential to 1) increase our understanding of cancer and 2) be used in so many other ways. Three cheers for science.

Sources: Here and here.

There are more planets than stars

I have long wanted to put forth the point that there are more planets than stars in the Universe. This goes to my contention that it is reasonable, even necessary, to believe that there is copious life in the Cosmos. After all, from the time when Earth’s surface cooled to when life began to appear was relatively short. It appears that all it takes for self-replicating molecules to get going is the right conditions. With so many planets, the opportunities are so vast; it has surely happened over and over again.

But I haven’t been able to make this exact point. I have still made the same effective point, but I had to rely on the trillions and trillions of stars. Of course, plenty of people have inferred over the years, especially the past decade, that there must therefore by billions, maybe trillions of planets. But we need something more concrete. We need observation. And now it looks like we’re there:

Three studies released Wednesday, in the journal Nature and at the American Astronomical Society’s conference in Austin, Texas, demonstrate an extrasolar real estate boom. One study shows that in our Milky Way, most stars have planets. And since there are a lot of stars in our galaxy — about 100 billion — that means a lot of planets.

It could be that the Milky Way is a weird outlier, a galaxy where planets are easy to make. But there isn’t any reason to suspect that. The observations show that we are an average galaxy with an expected array of stars. What’s more, we are seeing what happens around stars. It isn’t just that these giant gas balls form in space and that’s that. No, it’s much more. Most of them come with their own planetary pals. An accurate average of the star-to-planet ratio remains to be seen (they say 1.6 planets per star, but that is probably extremely low), but it is clear that we’re talking about trillions and trillions out there.

None of this changes the thrust of my argument about exo-life, but it does allow me to be much more specific. This is very nerdexciting.

DNA Portrait

Examples of evolution

Here are some basic examples of evolution for those zealots who still reject good science in favor of their unfounded belief in magic.

https://i0.wp.com/blog.wired.com/wiredscience/images/2008/12/30/nat3feathereddinoa.jpg

More snails

I love me some snail.

Biologists have tracked down genes that control the handedness of snail shells, and they turn out to be similar to the genes used by humans to set up the left and right sides of the body.

The finding, reported online in advance of publication in Nature by University of California, Berkeley, researchers, indicates that the same genes have been responsible for establishing the left-right asymmetry of animals for 500-650 million years, originating in the last common ancestor of all animals with bilateral body organization, creatures that include everything from worms to humans.

“Previous studies indicated that the methods for breaking left-right symmetry in animals seem to differ widely, so there was nothing suggesting that the common ancestor of humans, snails and other bilateral organisms had a common strategy for left-right asymmetry,” said Nipam H. Patel, UC Berkeley professor of integrative biology and of molecular and cell biology, and an investigator of the Howard Hughes Medical Institute.

“Indeed, scientists thought that one of the genes that is critical for setting up left-right asymmetry in vertebrates was only present in vertebrates and related groups and not in any other animals,” said UC Berkeley post-doctoral fellow Cristina Grande. “But we found that gene in snails, which has a lot of evolutionary implications. This cellular pathway was present already in the ancestors of most animals.”

There isn’t much I have to add to this right now. It’s just another good piece of evolutionary study. Pretty.