See the First 3D Images of Bacteria's 'Biological Wheels'

Believe it or not, humans didn't invent the wheel. Long before we showed up, some of nature's tiniest organisms had already evolved wheel-like nanostructures to propel themselves through liquid media. Now, scientists have found a way to image bacteria's naturally occurring, biological wheels for the first time, New Scientist reports.

Most bacteria maneuver themselves around using tiny protein motors that power a spinning flagellum tail, which is no more than tens of nanometers wide. While scientists know that different motor structures produce different levels of mobility in bacteria, they haven't been able to study the details of these mechanisms—until now. According to the study recently published in the journal PNAS [PDF], researchers at Imperial College London used an electron microscope to capture the first-ever 3D renderings of these structures, which you can see below.

By freezing the bacteria through a process called electron cryo-tomography, they were able to image the motors from multiple angles. They looked at a handful of various bacteria samples—including Campylobacter and Salmonella—to see how their wheels differed. Flagella generate their torque from wheel-like structures around the motor called stators. Different bacteria have different amounts of stators, which in turn come in different shapes, sizes, and strength levels. Campylobacter, which has nearly double the stators of Salmonella, has enough propulsion power to penetrate your stomach lining.

The high-resolution images could be used by nanoroboticists to develop better motors in the future, or they could find a way to incorporate the biological wheels into their robots to avoid building them from scratch. Better understanding the mechanisms behind the structures could also help us to target harmful bacteria more efficiently. You can read the full report in PNAS.

Vibrio motor // Imperial College London

Salmonella motor // Imperial College London

Campylobacter motor // Imperial College London

[h/t New Scientist]

People Listen (and Remember) Better With Their Right Ears, Study Finds

If you’re having trouble hearing in a noisy situation, you might want to turn your head. New research finds that people of all ages depend more on their right ear than their left, and remember information better if it comes through their right ear. The findings were presented at the annual meeting of the Acoustical Society of America in New Orleans on December 6.

Kids’ ears work differently than adults' do. Previous studies have found that children's auditory systems can’t separate and process information coming through both of their ears at the same time, and rely more on the auditory pathway coming from the right. This reliance on the right ear tends to decrease when kids reach their teens, but the findings suggest that in certain situations, right-ear dominance persists long into adulthood.

To study how we process information through both our ears, Auburn University audiologists brought 41 adult subjects (between the ages of 19 and 28) into the lab to complete dichotic listening tests, which involve listening to different auditory inputs in each ear. They were either supposed to pay attention only to the words, sentences, or numbers they heard in one ear while ignoring the other, or they were asked to repeat all the words they heard in both ears. In this case, the researchers slowly upped the number of items the test subjects were asked to remember during each hearing test.

Instructions for the audio test read 'Repeat back only the numbers you hear in the right ear.'
Sacchinelli, Weaver, Wilson and Cannon - Auburn University

They found that the harder the memory tests got, the more performance varied between the ears. While both ears performed equally when people were asked to remember only four or so words, when the number got higher, the difference between their abilities became more apparent. When asked to only focus on information coming through their right ear, people’s performance on the memory task increased by an average of 8 percent. For some people, the result was even more dramatic—one person performed 40 percent better while listening with only their right ear.

"Conventional research shows that right-ear advantage diminishes around age 13, but our results indicate this is related to the demand of the task,” one of the researchers, assistant professor Aurora Weaver, explained in a press release. In other words, when the going gets tough, the right ear steps up.

Pigeons Are Secretly Brilliant Birds That Understand Space and Time, Study Finds

Of all the birds in the world, the pigeon draws the most ire. Despite their reputation as brainless “rats with wings,” though, they’re actually pretty brilliant (and beautiful) animals. A new study adds more evidence that the family of birds known as pigeons are some of the smartest birds around, as Quartz alerts us.

In addition to being able to distinguish English vocabulary from nonsense words, spot cancer, and tell a Monet from a Picasso, pigeons can understand abstract concepts like space and time, according to the new study published in Current Biology. Their brains just do it in a slightly different way than humans’ do.

Researchers at the University of Iowa set up an experiment where they showed pigeons a computer screen featuring a static horizontal line. The birds were supposed to evaluate the length of the line (either 6 centimeters or 24 centimeters) or the amount of time they saw it (either 2 or 8 seconds). The birds perceived "the longer lines to have longer duration, and lines longer in duration to also be longer in length," according to a press release. This suggests that the concepts are processed in the same region of the brain—as they are in the brains of humans and other primates.

But that abstract thinking doesn’t occur in the same way in bird brains as it does in ours. In humans, perceiving space and time is linked to a region of the brain called the parietal cortex, which the pigeon brains lack entirely. So their brains have to have some other way of processing the concepts.

The study didn’t determine how, exactly, pigeons achieve this cognitive feat, but it’s clear that some other aspect of the central nervous system must be controlling it. That also opens up the possibility that other non-mammal animals can perceive space and time, too, expanding how we think of other animals’ cognitive capabilities.

[h/t Quartz]


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