Wednesday, October 8, 2008

Glowing jellies on the global stage

Osamu Shimomura, a scientist emeritus at the Marine Biological Laboratory, was named co-recipient of the 2008 Nobel Prize in Chemistry. The prize recognizes his pioneering work isolating what we now call the Green Flourescent Protein (GFP). After successfully isolating a glowing protein from a mollusc, Shimomura spent a summer cutting the light organs off of jellyfish and gathering what he poetically called "the squeezate" - literally, the liquid that he sqeezed out. After sqeezing thousands of the jellyfish Aequorea victoria, which were abundant around Friday Harbor Laboratory (where the work was done), he and his colleagues were able to purify a tiny amount of the luminescent blue photoprotein aequorin. Check out this animation to see how jellyfish use the two proteins (aequorin and GFP) to produce flashes of light! Many jellies can glow when they are disturbed, possibly as a way of avoiding predators.

Since GFP was cloned, it can and has been applied to all kinds of cells in plants and animals to examine, for example, how our genes are turned on and off, how diseased cells are different from healthy cells, and how animals develop. In the image to the left(source), you can see a worm whose nervous cells are all lit up with GFP. Now a routine tool that researchers employ, GFP has enabled major discoveries in cell physiology, neuroscience and cancer biology. It's also led to some pretty stunning images: check out the most beautiful brain pictures you've ever seen, and have a look at a glowing bunny art project.

Thursday, October 2, 2008

Fly like an osprey

One of the sounds of summer around here is the distinctive call of ospreys. Quite often it heralds the return of a parent, fresh catch in its claws, to the shrieking nest. The nest at the Oceanographic Institution is outfitted with a great video camera, so even from home you can check in on the fledglings over the course of the summer.

But now fall is in the air and all the ospreys and their fledglings have disappeared. They're off on incredible solo flights to their wintering grounds in South America. Rob Bierregaard, a scientist who helped engineer the local osprey comeback (after their decimation from DDT in the 1960s), is now involved in a study that satellite tags young birds to see exactly where they go.

The 2008 migration is already astonishing. One young female, Penelope, left the Vineyard at the beginning of September and traveled in a straight shot down the East Coast to North Carolina, headed out over the sea, past the Bahamas, and is already soaking up the sun in Venezuela! That was 2,700 miles in only 13 days, taking no days off. Other birds, like Meadow, got a little sidetracked. She's been exploring the great lakes and it's yet to be seen whether she gets on board with this southern migration thing...

Tuesday, September 30, 2008

One sick virus

The Mimivirus is the largest virus known, so large that it was initially mistaken for a bacterium (okay, still really small by our standards!) living inside of an amoeba. Since 2003, we've known it is actually a giant virus infecting an amoeba. Now we know that Mimi can get sick too. A different and remarkably small virus, called Sputnik, makes its living by infiltrating the Mimivirus factory and reproducing faster, a process that also leads to the formation of fewer, and "sicker" (that is to say, deformed) Mimiviruses. Since Sputnik hurts the Mimivirus, and is incapable of infecting an amoeba without the Mimivirus, it could be considered a viral parasite of another virus.

This ecological relationship is intriguing because viruses fall into a tricky category between the living and the nonliving. We think of single cells as the simplest form of life, but viruses don't even have a cell. Other hallmarks of the living, like eating and being able to reproduce with others of your species or alone, are conspicuously absent. Reproduction depends on hijacking a cell, and using its machinery and energy to set up a virus factory that pumps out new viral particles. But just like living organisms, viruses do have genes and are evolving through natural selection.

The Mimivirus has a lot of genes for a virus (911) and some of them seem to come from shuffling genes with amoeba hosts and other microbes. Sputnik only encodes 21 genes, which is why it requires a helper like Mimi to make multiplication possible. The cool thing about those 21 genes is that they are closely linked to a variety of other viruses that infect really diverse organisms - bacteria, eukaryotes, and archaea. Where do viruses like Sputnik come from? And what is the ecological relationship between small and large viruses, if any?

Evidence might be in the ocean! Some of the genes identified as being most similar to Sputnik's came from Craig Venter's Global Ocean Survey. The authors of the study (La Scola et al. 2008, in Nature) point out that large viruses, similar to the Mimivirus, are abundant in the ocean. The small viruses in the sea are able to quickly multiply like Sputnik. Sometimes both small and large viruses can be found in marine amoebae. Large and small viruses could evolve to trade genes and depend on each other in different ways. And small viruses could shuttle genes between large viruses.

Learning more about the ecology of viruses may or may not get us closer to understanding whether they're alive, but could help us understand some big picture processes. Viral infection is an important regulator of marine microbes... and marine microbes are responsible for some major chemical fluxes that regulate the climate on our planet. But more on that another time!

Monday, September 29, 2008

a blog is born...

This blog is rooted in exploring the amazing "blue planet" we live on - whose inherent fascination was well described by one very famous frenchman:

"The sea, once it casts its spell, holds one in its net of wonder forever."

Getting tangled up in that net is what scientists do for a living, incrementally figuring out what's going on in the natural world. Cousteau was able to share his appreciation of the beauty and complexity of the sea with thousands worldwide by giving people a window on the underwater world. Beyond scientific journals, many intriguing science stories are easily accessible. Anyone can marvel at a tide pool, or wonder what the birds in your backyard are up to.

Here I'll explore science news and views. These will not be limited to oceanography, but because I am a marine scientist, will seen through through a watery lense. And I hope this "net" becomes an interactive community that encourages observation of life around us.