It's not exactly the set of TV's "American Ninja Warrior," but a tiny obstacle course for bacteria has shown researchers how E. coli changes its behavior to rapidly clear obstructions to food. Their work holds implications for not only biology and medicine, but also robotic search-and-rescue tactics.
Scientists at Carnegie Mellon University, the University of Pittsburgh and the Salk Institute for Biological Studies report today in the Proceedings of the National Academy of Sciences that the well-known "swim and tumble" behavior that bacteria use to move toward food or away from poisons changes when bacteria encounter obstacles.
"In the real world, they always encounter lots of obstacles," said Ziv Bar-Joseph, a professor in CMU's Computational Biology and Machine Learning departments. E. coli, for instance, inhabits the complicated terrain of the gastrointestinal tract. Yet previous studies of chemotaxis -- the way bacteria move toward a higher concentration of food or away from concentrations of poisons -- generally have been done in unobstructed chambers.
Existing models of chemotaxis predict that obstacles will slow the progress of bacteria. So the researchers designed microfluidic chambers -- just 10 micrometers high, one millimeter wide and one millimeter long -- and placed evenly distributed square and round obstacles in them. When they tested E. coli inside these tiny obstacle courses, they were surprised at the speed at which the bacteria found a food source.
"Almost regardless of the obstacles, they got to the food almost as quickly as they did without obstacles," said Sabrina Rashid, a CMU PhD student in computational biology and the lead author on the study. "The obstacles were not affecting the time they needed to reach food, as the previous models predicted."
Bacteria are known to communicate with each other by secreting chemicals, and this sort of communication no doubt informs bacteria as they try to get around an obstacle, she said. But a closer look at the bacteria also showed a change in behavior.
Normally, bacteria swim a bit, then perform a circular dance, called tumbling, to reorient themselves regarding food concentrations. The tumbling slows progress toward food, but importantly enables bacteria to make course corrections.
The researchers suspected that a key reason for the improvement in speed when facing obstacles is the bacteria's ability to tumble less and swim more until they are in the clear. So they designed additional experiments that tracked individual bacteria cells and confirmed these predictions.
Given the importance of cell movement in biology, the new findings could have implications for how malignant cells spread through the body or how infections might be treated, Bar-Joseph said.
Based on these findings the researchers have developed their own chemotaxis model to account for this new behavior and better predict the performance of bacteria. Applying the model to simulations of teams, or swarms, of robots performing searches for trapped victims in emergencies has shown that this approach can reduce their search time as well.
"Any type of insight we can get from biology to improve computation is important to us," Bar-Joseph added.
In addition to Bar-Joseph and Rashid, the research team at CMU included Shashank Singh, a PhD student in machine learning and statistics. At Pitt, Hanna Salman, associate professor of physics and astronomy, and Zoltan Oltvai, associate professor of pathology, were joined by Zicheng Long, a post-doctoral researcher in Salman's lab, and Maryam Kohram and Harsh Vashistha, both Ph.D. students in physics. Saket Navlakha, an associate professor at the Salk Institute, completes the team.
The National Science Foundation supported this research.
Source: Carnegie Mellon University
Dear Helpdesk: Working in a Toxic Health Care Environment
March 28th 2024Dear Helpdesk is your steadfast companion, offering life coaching and workplace advice from 2 seasoned IPs for some of your most challenging real-life situations. Let us help you navigate the intersection between work and life, guiding you to navigate the dynamic world of infection prevention with confidence and grace. This article is on handling a toxic health care environment.
Product Locator: Spring and Early Mother's Day Gift Guide for Infection Prevention Personnel
March 27th 2024Whether it's a spring holiday, birthdays, or no reason at all, infection prevention personnel love to give and receive gifts that help at the end of a stressful day. Infection Control Today® offers some gift ideas for infection prevention personnel and their families.
Catching Up With Vangie Dennis, AORN 2022-2023 President at AORN 2024
March 26th 2024Infection Control Today (ICT) had the privilege of catching up with Vangie Dennis, MSN, RN, CNOR, CMLSO, at the Association of periOperative Registered Nurses' (AORN’s) International Surgical Conference & Expo 2024. As the former president of AORN and an esteemed figure in perioperative services, Vangie Dennis shared insights into her recent endeavors and the exciting new chapter she's embarked upon.
How To Optimize Your Time Management Strategies for the Busy Infection Preventionist
March 25th 2024Is your calendar resembling a chaotic masterpiece of overlapping tasks? Join the club of infection preventionists striving to balance responsibilities. Dive into proven strategies from a fellow infection preventionist to reclaim control of your time, streamline tasks, and boost productivity effectively. This is an IP Lifeline article.