And what are the reasons?
Hello, Reddit!
We are members of Iverson Lab at Vanderbilt University, Dr. Tina Iverson and Prash Singh. We study the connection between metabolism and cell fate when organisms respond to their environments. One of our projects seeks to understand how bacteria use a nano-motor to move in response to environmental conditions. This is important because these nano-motors allow bacteria to move towards energy-rich environments for survival and hide from antibiotics during infections. Globally, bacterial infections account for 1 in 8 deaths each year. Currently, antibiotics are our best defense; however, due to factors such as antibiotic misuse/overuse, genetic mutations, and gene transfers, bacteria are becoming increasingly resistant to these drugs bacteria are becoming increasingly resistant to these drugs. There is an urgent need for alternative approaches to combat harmful bacteria.
How does a very small motor direct bacteria? Think of bacteria as tiny boats that have propellors but no rudders. This means that their propellers have to be able to guide the direction. These specialized propellors are called flagella, which resemble Indiana Jones-style whips. Depending on how the bacteria rotate the flagella, these features can both serve to move the bacteria forward and change the direction of swimming. At the base of each of the flagella is a very small and extremely efficient rotary motor that controls this direction of flagellar rotation and is the key to the entire process.
To visualize and understand the inner workings of the bacterial flagellar motor our recent research used a technique called cryo-electron microscopy. We captured and analyzed millions of pictures of these bacterial nano-motors at 100,000-fold magnification. We then combined them to reconstruct models of the different states of the motor which are shown here: . Our results suggest that the motor uses interlaced cogwheels to change how the flagella rotate and guide the bacteria . We can also propose how this nano-motor can accept torque from multiple sources so that bacteria can swim at different speeds ().
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