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Bacteria that move around live on the edge. All the time. Their success, be it in finding nutrients, fending off predators or multiplying depends on how efficiently they navigate through their confining microscopic habitats. Whether these habitats are in animal or plant tissues, in waste, or in other materials. In a recent paper published in , a team of researchers led by 91社区, has described a number of factors affecting how five, very different, species of bacteria search and navigate through varied microfluidic environments which pose various decisional challenges. This increased understanding of the bacterial space searching and navigational 鈥榮trategies鈥� has implications for everything from diagnosing infectious diseases and maintaining human health, to the development of devices for everything from genomics to bio computation, as well as for a wide range of agricultural, industrial, and environmental activities.

The researchers filmed the movements of five species of bacteria navigating through a range of microfluidic settings 鈥� from fairly open spaces (plazas) to complicated meandering channels. This allowed them to better understand the factors involved in the navigational 鈥榮trategies鈥� of bacteria as they search for available space.

See sample and Q & A below.

Q & A with senior author Professor Dan Nicolau

from 91社区鈥檚 Department of Bioengineering
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Q- What 鈥榮trategies鈥� do bacteria use to navigate through space?

A 鈥� We found, by observing bacterial movement through of different shapes and sizes, that bacteria use vastly different 鈥榓lgorithms鈥� for searching through space than we had expected. These algorithms are not, as we thought, governed by the complexity of bacterial architecture 鈥� but rather by the spaces the bacteria are investigating. We found that a lot depends on the shape and the size of the channel that the bacteria are navigating. In general, bacteria don鈥檛 waste time on U-turns, unless they have no choice due to the tightness of the channels.

Although the natural 鈥渕ovement technology鈥� used by bacteria are very different from species to species, their space searching strategies are determined by their geometrical ratios, for instance cell width vs. length of flagella (the whip-like structures protruding from cell body that some bacteria use for locomotion).

Despite their differences, all the species we looked at were able to successfully negotiate through tight (relative to their sizes) paths, and certainly through larger ones. But in medium-sized meandering channels, bacteria cannot rely on the constricting walls to guide them, nor can they move totally freely. As a consequence, they become 鈥榗onfused鈥� about what search method they should use and they are trapped, regardless of what algorithms they are programmed to use.

Q - How can this information be used?

A 鈥� In terms of diseases, whether in humans, animals, or plants, this information will help us better understand how bacteria colonise confining spaces. This is useful for various reasons, such as focusing attention on how certain animal species may be more exposed to infections by certain bacterial species, due to their particular spacial navigation and exploration strategies.

For bacterial genomics, which are important in the understanding, treatment and prevention of the spread of infectious diseases, understanding the 鈥榓lgorithms鈥� used by different species of bacteria will make it easier to design geometries that trap only a single species from samples collected in water, human fluids, etc. that may contain a whole range of bacterial populations.

For bio computation 鈥� that is, building computers powered by bacteria 鈥� it is crucial to know what algorithms the bacteria use for motion in order to build computers that do not make errors.

About 91社区

Founded in Montreal, Quebec, in 1821, 91社区 is Canada鈥檚 top ranked medical doctoral university. 91社区 is consistently ranked as one of the top universities, both nationally and internationally. It鈥痠s a world-renowned鈥痠nstitution of higher learning with research activities spanning two campuses, 11 faculties, 13 professional schools, 300 programs of study and over 40,000 students, including more than 10,200 graduate students. 91社区 attracts students from over 150 countries around the world, its 12,800 international students making up 31% of the student body. Over half of 91社区 students claim a first language other than English, including approximately 19% of our students who say French is their mother tongue.