Bacteria Sense and Move Toward Chemicals

close up photograph of bacteria in a petri dish

Biological Strategy

Escherichia coli

AskNature Team

Image: Rattiya Thongdumhyu / Shutterstock / Some rights reserved

Sense Chemicals (Odor, Taste, etc.) From the Environment

Chemicals are important for signaling and communication among living systems, either intentionally (such as when two living systems try to find one another) or unintentionally (such as when a plant emits a chemical signal that an herbivore can use to find a tasty bite). They are also important for other uses, such as navigating or finding sources for minerals. But chemical signals are often relatively weak and disperse when moving through water or gases. Therefore, detecting them requires specialized abilities, including a way to determine where they are coming from. A well known example of sensing chemicals can be seen in ants following a pheromone trail laid down by others in their colony to locate a quality and abundant food source.

Search this Function

Bacteria

Domain Bacteria (“small staff”): L. acidophilus, Staphylococcus

From inside of our own bodies to the deepest parts of the ocean, bacteria have adapted to almost every possible environment. All bacteria are unicellular, microscopic, and lack a membrane-bound nucleus and organelles, and come in three basic shapes: spherical (cocci), rod (bacilli), and spiral (spirilla). Some strains can be deadly, like Staphylococcus aureus (MRSA) while others, like Lactobacillus acidophilus, found in our intestinal microbiome, keep us healthy. Cyanobacteria, also known as blue green algae, caused the Great Oxidation Event 2.4 billion years ago, producing Earth’s first oxygenated atmosphere.

Search this Living System

The membrane of E. coli bacteria detects chemicals of interest via transmembrane receptor proteins.

“Chemotactic bacteria navigate complex chemical environments by coupling sophisticated information processing capabilities to powerful molecular motors that propel the cells forward. Escherichia coli recognize chemoattractants using five transmembrane receptor proteins, which cluster with one another and interact with a set of well-characterized cytosolic proteins to effect changes in the directional rotation of the flagellar motor.” (Topp 2007:6807)

Last Updated September 14, 2016

References

Journal article

Guiding Bacteria with Small Molecules and RNA

J. Am. Chem. Soc. | 23/05/2007 | Shana Topp, Justin P. Gallivan

embedly preview

Reference

Other Biological Strategies

a brown moth with large antennae sits on a grass stem against a grassy background and blue sky

Biological Strategy

Moths Make Sense of Barely-There Scents

Moths

Moth antennae sense specific airborne molecules in minute concentrations.

two red orange lobsters with long antennae navigate underwater

Biological Strategy

Sensors Trap Underwater Odors

Caribbean spiny lobster

Antennules of the spiny lobster trap water to identify odors using chemosensory hairs.

Cataglyphis ant in the Ebro Depression in Spain

Biological Strategy

How Tunsian Desert Ants Smell in Stereo

Desert ant

The antennae of the Tunisian desert ant create a detailed olfactory map by detecting smells in left and right channels.

woman wearing yellow shirt smiles while inhaling cup of coffee

Biological Strategy

How Mucus Helps Crack the Smell Code

Humans

Inhaled molecules absorb into mucus in the nasal epithelium and bind with olfactory receptors, triggering a unique code that tells the brain what it’s smelling.

Biological Strategy

How Fruit Flies Follow a Scent

Common fruit fly

Insects use an alternating pattern of searches and surges to make sense of an inconsistent trail.

Biological Strategy

Serotonin Increases Sociability, Triggers Swarming

Desert locust

The desert locust becomes social and forms swarms through an increase in serotonin triggered by the presence of other locusts.