Recent research has found that some pathogenic bacteria are cavalier explorers on human mucosal surfaces. They perform these three incredible feats all while completely ditching their classic propeller-like flagella. Scientists have found that these microbes are very good at taking advantage of sugar powered chemical currents and novel molecular machines to move themselves around. Only two studies have explicitly elaborated these mechanisms. Their emphasis is on flavobacteria, salmonella, and E. coli—bacteria that can make their way around rather well in the absence of flagella, even.
Abhishek Shrivastava and his research team did pioneering work on studying flavobacteria. At the same time, Navish Wadhwa and his co-authors focused on research regarding salmonella and E. coli. Their results contradict long-held notions about how bacteria move and go a long way in paving the way for future microbial studies focused on dispersal.
Innovative Movement Techniques
For decades, it was assumed that bacteria could not swim without their flagella. According to some recently released data, they don’t just move by walking and biking. These little guys are able to “swarm” across surfaces, creating chemical currents from fermentable sugars that propel them in waves. This unusual way to move opens up new environments, enabling them to be mobile even in environments where traditional flagella are not present.
Besides swashing, flavobacteria use a special molecular conveyor belt system to move across surfaces. This system is powered by a type of machine called the type 9 secretion system (T9SS). The T9SS is not just a highway that allows them to move, but rather is crucially involved in the secretion of many substances.
The intricacies of bacterial movement are further illuminated by the role of a specific protein known as GldJ in flavobacteria. GldJ serves as a gear-shifter, adjusting the direction of the bacteria’s rotary motor in a complex animal conveyor belt system. Notably, removal of just a few amino acids from GldJ leads to reversed motor directionality, highlighting its important role in chemotactic behavior.
“We were amazed by the ability of these bacteria to migrate across surfaces without functional flagella. In fact, our collaborators originally designed this experiment as a ‘negative control,’ meaning that we expected (once rendered) flagella-less, the cells to not move.”
The latter two types of movement, swashing and swarming, use different physical mechanisms. For instance, surfactants have a significant impact on bacterial motility. Scientists are now able to do this to specific strains of bacteria, in either direction if the bacteria are swashing or swarming. This new window into bacterial behavior gives scientists a more nuanced view of how these tiny microorganisms react and respond to their surroundings.
Mechanisms Behind Bacterial Movement
The implications of these discoveries go much further than fundamental microbiology. Learning the mechanics of how bacteria move can lead to innovations in the field of bioengineering and therapeutics. The study’s authors now aim to reveal high-resolution structures of the enigmatic molecular conveyor belt. They want to be able to visualize its components, with atomic precision.
As researchers continue to explore these novel bacterial movement techniques, they may uncover further surprises that could reshape our understanding of microbial life and its applications in various fields.
Shrivastava expressed excitement over their findings, stating:
“We are very excited to have discovered an extraordinary dual-role nanogear system that integrates a feedback mechanism, revealing a controllable biological snowmobile and showing how bacteria precisely tune motility and secretion in dynamic environments.”
Implications for Future Research
The implications of these discoveries extend far beyond basic microbiology. Understanding the mechanisms behind bacterial movement can inspire advancements in bioengineering and therapeutics. The study’s authors aim to determine high-resolution structures of the molecular conveyor system to visualize its components at atomic precision.
Shrivastava highlighted the potential impact of this research:
“Building on this breakthrough, we now aim to determine high-resolution structures of this remarkable molecular conveyor to visualize, at atomic precision, how its moving parts interlock, transmit force and respond to mechanical feedback. Unraveling this intricate design will not only deepen our understanding of microbial evolution but also inspire the development of next-generation bioengineered nanomachines and therapeutic technologies.”
As researchers continue to explore these novel bacterial movement techniques, they may uncover further surprises that could reshape our understanding of microbial life and its applications in various fields.