Bacteria Make Magnets to Fit Their Environment

Biological Strategy

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Modify Material Characteristics

The materials found in living systems are variable, yet often made from the same basic building blocks. For example, all insect exoskeletons consist of a material called chitin. Because material resources are limited, each material within or used by a given living system must frequently serve multiple purposes. Therefore, living systems have strategies to modify materials’ softness, flexibility, and other characteristics. To ensure survival, the benefits of these modifications must outweigh the living system’s energy and material expenditure to generate them. For example, spiders store the liquid components of spider silk in a gland, converting them into silk thread when needed. Some threads have different characteristics, such as elasticity and UV reflectance, than others.

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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.

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Magnetic crystals inside cells are influenced by both genes and conditions.

Some bacteria, such as a new sulfate-reducing bacteria found in the class Deltaproteobacteria, produce magnetosomes to help them move along geomagnetic fields. A magnetosome is an “intracellular membrane-bound magnetic crystal made of the minerals magnetite (FeO) or greigite (FeS)” (Jermy A. 2012. Environment shapes magnetic personality. Nature Reviews: Microbiology. Research Highlights. Vol 10. 2012). Genes within bacteria are responsible for the production of magnetosomes (i.e., magnetosomes are controlled by magnetosome genes- mam genes). New research shows that magnetosomes are affected by the environmental parameters–thus, magnetotactic behaviors vary depending on the environmental conditions. This research could prove important in understanding how different biomaterials used in construction vary under changing environmental conditions.

Last Updated August 23, 2016

References

Journal article

A cultured greigite-producing magnetotactic bacterium in a novel group of sulfate-reducing bacteria

Science

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