how bacteria shift gears细菌是如何改变方式.pdfVIP

Synopsis How Bacteria Shift Gears Robin Meadows* Freelance Science Writer, Fairfield, California, United States of America Bacteria can change course almost counterclockwise to clockwise have proven revolutions per minute. The rotor shifts instantaneously, zipping towards food or difficult to identify. Now, in a new study in from the forward-propelling counterclock- away from toxins. How do such simple this issue of PLoS Biology, Katsumi Imada, wise to the tumble-inducing clockwise organisms do something so complex? It’s Tohru Minamino and colleagues bring us when chemical gradients tell bacteria all in the flagella, a tail-like structure with closer to answering this fundamental they’ve gone astray, for example, away rotating helical filaments. The flagella question and propose a new model from food. This activates a cytoplasmic work in unison to propel the cell forward describing how flagella manage this signaling protein that binds proteins in the by rotating counterclockwise and thus switch. rotor switch, changing the orientation of bundling together. When the flagella Filaments in the flagella are powered by another switch protein called FliG and reverse their rotation to clockwise, they rotary motors that span the cell mem- thereby reversing the rotor’s spin to disrupt the bundle and make the cell brane. Things of beauty, these motors are clockwise. tumble in place. When the flagella shift tooled so precisely that they are nearly The