Analyzing Energy Storage Structures in Archaea

Until the 1970s, experts did not distinguish unicellular organisms called archaea from bacteria and eukaryotes. But now that these lifeforms are understood more than they were four decades ago, experts are beginning to take a deep interest in the energy storage structures these cells have.

One of the things that stand out about archaea is the fact that they tend to be able to survive in some of the harshest environments this planet has to offer. As they study the microorganisms, researchers are realizing that there are vast volumes of data that they don't yet know about these lifeforms.

In a new study, experts at the University of California in Los Angeles (UCLA) looked at the archaea called Methanosprillum hungatei, and determined that that energy storage structure it contains are extremely efficient.

The scientists were so amazed that they say replicating these constructs could even improve modern-day technology. The work was led by UCLA professor of microbiology, immunology and molecular genetics Robert Gunsalus.

In order to conduct the research, experts use the capabilities of the UCLA California NanoSystems Institute (CNSI). Full details of the results appear in the July 5 issue of the renowned scientific journal Environmental Microbiology.

This is not the first time M. hungatei has been studied. Thus far, experts only tended to focus on the role these organisms played in the food chain. This was considered important because the archaea can enter a symbiotic relationship with syntrophic bacteria, which results in the production of methane.

Gunsalus was interested in these organisms for years, but he decided to investigate them in depth back in 2006, when professor of microbiology, immunology and molecular genetics Hong Zhou arrived at UCLA.

“When Hong came to UCLA, his reputation in imaging nanoscale structures was already well established. His arrival on campus brought together the expertise to do what no one had yet done – a detailed study of the sub-cellular structures in M. hungatei,” the expert says.

The latest study reveals that M. hungatei stores its energy in 150 nanometer-wide granules. “Once we imaged the M. hungatei, we noticed how dark the granules appeared,” says Zhou, who is also a researcher at the CNSI.

“The darkness arises from their density, and by studying this density, we discovered their energy-storage capacity,” the expert adds. The granules were found to be about four times denser than water.

Each of the granules can store 100 times more energy than the rest of the cell, even if they themselves account for just 0.5 percent of the cell. Each M. hungatei cell has two such granules.

“M. hungatei have evolved unique features in order to survive in very harsh and low-energy environments. The presence of cutting-edge equipment and world-class experts at UCLA allows us to closely study them, hopefully revealing their myriad of secrets,” Gunsalus concludes.