Do Cells Make Noise?

You have to listen very, very closely, but yes, cells produce a symphony of sounds. Although they won’t win a Grammy anytime soon, the various audio blips produced by cells give scientists insight into cellular biomechanics and could even be used to help detect cancer.

Researchers at the University of California at Los Angeles studying brewer’s yeast discovered that the yeast’s cell walls vibrate 1,000 times per second. These motions are too slight and fast to be caught on video, but when converted into sound, they create what the scientists describe as a high-pitched scream. It’s about the same frequency as two octaves above middle C on a piano, but it’s not loud enough to hear with the naked ear. “I think if you listened to it for too long, you would go mad,” says biological physicist Andrew Pelling, at the University of Ottawa. Pelling and Jim Gimzewski, a professor of biochemistry at UCLA, theorize that molecular motors that transport proteins around the yeast cell cause the walls to vibrate.

It’s a little harder to get sound out of a human cell than from a yeast cell: So far, scientists have not observed mammalian cells that audibly shimmy on their own, at least in part because animal cells’ wiggly membranes are less likely to vibrate than the sturdy cell walls of yeast and plants. But human cells certainly squeal when zapped with light, a trait that could be surprisingly useful for medical science, particularly cancer research.

When Richard Snook and Peter Gardner, biologists at the University of Manchester in England, blasted human prostate cells with infrared light, their microphones picked up thousands of simultaneous notes generated by the cells.

Through statistical analysis of these sounds —which are created as the cells rapidly heat up and cool down, causing vibrations in the air molecules directly above them— Snook and Gardner can differentiate between normal and cancerous cells. “The difference between a healthy cell and a cancer cell is like listening to two very large orchestras playing their instruments all at the same time,” Gardner says. “But in the cancerous orchestra, the tuba is horribly out of tune.” Gardner is finetuning the technique in hopes of replacing current, unreliable pre-biopsy prostatecancer tests. His ultimate goal is to reduce the number of prostate biopsies performed, 75 percent of which come back negative.

Comments

What Causes Volcanic Lightning?

On March 10, 2010, Eyjafjallajökull volcano, a caldera in Iceland covered by an ice cap, erupted. It sent plumes of clouds across most of Europe and the Atlantic Ocean. Photos of the eruption show lightning originating and ending in the cloud of ash that hovered over the volcanic opening. The largest volcanic storms are similar to supercell thunderstorms that spread across the American Midwest. But while those thunderstorms are fairly well understood, volcanic lightning still remains mysterious. The remote location of volcanoes and infrequent eruptions make volcanic lightning difficult to study. In general, lightning occurs through the separation of positively and negatively charged particles. Differences in the aerodynamics of the particles separate the positive and negative. When the difference in charge is great, electrons flow between the positive and negative regions. A lightning bolt is a natural way of correcting the charge distributi...

Will Disease Drive Us All to Extinction ?

Virulent infectious diseases and parasites have long been shown to be a significant cause of decline in biological populations. But can disease lead to the actual extinction of the host species—such as humankind? Scientists attempt to determine the extinction-threatening effects of disease by first studying its role in historical extinctions. But proving that infectious disease is responsible for past extinctions is tricky business. After all, the extinct species is not around for scientific investigation. Even if a pathogen or parasite were discovered in a disappearing population, it would not prove that the pathogen itself was responsible for the decline. However, reasonable evidence exists that historical extinctions and extirpations—local extinctions in which a speciesc eases to exist in the specific geographic area of study—are at least partlya ttributable to infectious disease. Avian malaria and bird pox are believe...

How Will the Universe End?

In 1929, Edwin Hubble discovered that the universe is not in fact static, but expanding. In the years following his discovery, cosmologists took up the implications of the discovery, asking how long the universe had been expanding, what forces caused the expansion, and whether it will ever cease. Cosmologists are pretty confident about the first question: just shy of 14 billion years. A great deal of evidence supports the predominant answer to the second question: The universe rapidly emerged from a singularity in an event that cosmologists call the Big Bang. The third question is a bit more mysterious, and the answer relies on an obscure, confounding phenomenon known as dark energy. The density of dark energy in the universe determines its ultimate fate. In one scenario, the universe does not possess enough dark energy to forever counteract its own gravity and thus ends in a “Big Crunch.” Under this scenario, the universe’s gravity will overcome its expansio...

knowledge

Search This Blog