Category: Blog
When I talk about viruses, I have to struggle with big numbers.
If you get sick with the flu, for example, every infected cell in your airway produces about 10,000 new viruses. The total number of flu viruses in your body can rise to 100 trillion within a few days. That’s over 10,000 times more viruses than people on Earth.
Paleontologists have found traces of animal life dating back at least 635 million years. Those earliest animals may have been like today’s sponges, rooted to the sea floor and filtering food particles from the water. Over the next 100 million years or so, new kinds of animals emerged. Some were recognizable members of living groups of animals, while others were so bizarre that paleontologists suspect they belonged to long-extinct lineages. And then, around 520 million years ago, the fossil record of animals starts to roar like a firehose switched from a trickle to full blast. Many of the oldest known members of living animal groups–including our own–appear during the Cambrian Period. But the Cambrian fossil record is also rife with forms only distantly related to animals on Earth today, some of which were so weird that the sight of a reconstruction of the creatures made scientists burst out laughing.
Continue reading “The Weird Youth of the Animal Kingdom (Slide Show)”
Jonathan Kurtz writes, “I started graduate school four years ago, studying the immune responses to chronic Salmonella infection in mice, similar to typhoid fever in humans.
“My project developed into defining how infections are combated in different anatomical locations and the host/microbial factors dictate these responses. I am scheduled to do my post-graduate studies with a collaborator of ours, so that I may stay in the Salmonella field, studying what is now a lifetime love/interest/career.
Continue reading “Today’s Microbiology Class Will Be At the Tattoo Parlor (Science Ink Sunday)”
In the mid-1990s, people in the United States and Canada began to notice something grotesque. The frogs in their local ponds were sprouting extra legs.
As news of the deformed frogs spread, the Minnesota state government set up a hot line for sightings, and soon they got hundreds of calls from 54 out of 87 counties. “I’ve seen a lot of frogs over the years, and I’ve never seen anything like that,” a University of Minnesota herpetologist told the New York Times in 1996.
Ten years ago, Jonathan Kipnis decided to run an experiment to see how well mice can learn new things. He suspected that the immune system was important to cognition, and so he wanted to compare mice with normal immune systems to mice with deficient ones. Kipnis engineered mice that lacked T cells, a type of white blood cell that fights pathogens. At the time, Kipnis was getting his Ph.D. at the Weizman Institute in Israel, and the lab he was working in didn’t have the equipment necessary for the test. So he shipped off his mice–a group of normal ones and a group lacking T cells–to Ben-Gurion University. There, his colleague Hagit Cohen put the mice through their paces.
Cohen gave the mice a task known as the Morris water maze. She put them in a pool of water, where they started to swim frantically. Just under the surface of the water there was a hidden stand. If the mice could find the stand, they could climb onto it and stop their desperate swimming. Over several rounds, the mice learned where the stand was hidden and swam straight for it.