What looks like a microscopic dance battle is actually a life-or-death strategy. In scalding hot water rushing through narrow channels, some bacteria have evolved a surprising survival technique: they cling to surfaces, stand upright, and sway rhythmically—like tiny street dancers fighting the flow. Watch the video of the bacterial "reverse-flow dance": https://youtu.be/JDN28g-aE78
This dramatic behavior was captured for the first time on video by a team led by Dr. Daisuke Nakane, Associate Professor at the University of Electro-Communications in Tokyo, in collaboration with Professors Masatada Tamakoshi and Ryota Morikawa at Tokyo University of Pharmacy and Life Sciences.
The researchers were studying Thermus thermophilus, a rod-shaped bacterium found in Japanese hot springs where temperatures reach 70°C and water flows rapidly. Using a custom-built microscope system that mimics these extreme conditions, they discovered that the bacteria do not swim—in fact, they lack flagella—but instead move by attaching to surfaces and performing what they call the "reverse-flow dance." In this motion, the bacteria rise vertically from the surface and flutter in the current. This allows them to sense the direction of the water flow and reposition themselves, enabling them to crawl slowly but surely upstream. In just 30 minutes, a bacterium can move over a millimeter—a small step for bacteria, but a giant leap in understanding microbial life in harsh environments.
More than just a quirky curiosity, this behavior was found to be common among many heat-loving bacterial species, especially those with elongated shapes. In contrast, bacteria that live at room temperature and tend to be rounder showed no such response. This suggests that both shape and environment play key roles in this upstream crawling mechanism. "I was completely surprised when I saw this movement for the first time," said Mr. Naoki Uemura, a graduate student in Nakane Lab. "It shows how microorganisms can adapt physically and behaviorally to environments where swimming is not an option." The discovery could have practical implications too. Understanding how bacteria attach to and move along surfaces in fast-flowing, high-temperature environments may help design better systems for industrial bioreactors, wastewater management, or even prevent unwanted biofilm formation in pipelines.
The research was published in The ISME Journal under the title: "Rapid water flow triggers long-distance positive rheotaxis for thermophilic bacteria"
