Month: September 2025

A molecule that enables microbes to eat methane

September 4, 2025

A molecule that enables microbes to eat methane

September 4, 2025
Above: A model of methylocystabactin (gray) binding an iron atom (orange). Credit: Andrew Roberts and Aaron Puri

U chemists discover critical step bacteria take to oxidize potent greenhouse gas and how they interact in larger microbial communities

Aaron Puri

Because of its potent greenhouse properties, methane gas is a significant contributor to climate change. It also feeds microbes known as methanotrophs that convert the gas into carbon dioxide and biomass, but scientists have been unsure how these microbes get all the nutrients they need to accomplish this task.

Now, a University of Utah chemistry lab has developed a novel technique for studying these microbial communities and has used it to discover a new molecule that enables methane-oxidizing bacteria to acquire iron from the environment, which is important for understanding how these organisms sequester methane, keeping it out of the atmosphere.

The findings, to be published Friday in PNAS, also provide information that could be useful for harnessing methanotrophs to convert methane into useful chemicals and liquid fuels, according to principal investigator Aaron Puri, an assistant professor of chemistry and member of the U’s Henry Eyring Center for Cell & Genome Science.

“Understanding these types of mechanisms that they use to interact with their environment is critical if we’re going to optimize using them for useful tasks,” Puri said. “We’ve also identified a key link between how iron exists on Earth and how gases are cycled in the atmosphere, which is through these methane-oxidizing bacteria, and more specifically through this new molecule that we’ve discovered.”

Methane, or CH4, the simplest hydrocarbon molecule, is the main ingredient of natural gas that fuels home appliances. This gas is also released from decomposing organic matter, commonly at landfills or swamps. It packs about 80 times more heat-trapping power in the short term than carbon dioxide, a longer-lived gas that is the main driver of anthropogenic climate change.

Microbes naturally break down CH4 through an oxidation process that yields carbon dioxide and organic compounds.

Puri’s study introduces a new tool called “inverse stable isotope probing–metabolomics,” or InverSIP, which links genes found in microbial DNA with the actual small molecules called metabolites those genes produce. Using this method, the Puri Lab discovered a previously unknown iron-grabbing molecule made by methane-eating bacteria. They dubbed the molecule methylocystabactin.

It functions like a claw that pulls iron from the environment and makes it available for enzymes that oxidize methane. But it gets even more interesting.

Read the full story by Brian Maffly in At the U. 

Oxygen came late to ocean depths during Paleozoic

September 4, 2025

Oxygen came late to ocean depths during Paleozoic

September 4, 2025

Thallium isotopes show O2 levels rose and fell at the ocean floor long after marine animals appeared and diversified half billion years ago, according to study of ancient marine sediments exposed by river cuts in Canada's Yukon

Chadlin Ostrander

The explosion of animal life in Earth’s oceans half a billion years ago during and after the Cambrian Period is commonly attributed to a substantial and sustained rise of free oxygen (O2) in seawater. Some researchers even argue for near-modern levels of ocean oxygenation at this time.

But O2 levels in Earth’s deepest marine environments fluctuated wildly long after the Cambrian, according to new research published by a University of Utah geologist with colleagues from other institutions.

Using stable isotope ratios of thallium (Tl) preserved in ancient marine mudrocks, the researchers reconstructed O2 levels between about 485 and 380 million years ago. This timeframe immediately follows the Cambrian rise of animals and even intersects the later rise of land plants. The findings, published this week in Science Advances, challenge some conventional views of ocean oxygenation, according to lead author Chadlin Ostrander, an assistant professor in Utah’s Department of Geology & Geophysics.

“It wasn’t like someone flipped a switch and the deep ocean became forever oxygenated,” Ostrander said. “Just a decade ago, it was thought that a deep ocean oxygenation switch was flipped around 540 million years ago. Our new dataset pushes that forward in time by at least ~160 million years.”

To reach these findings, Ostrander and his collaborators analyzed the stable isotopes of thallium—a heavy metallic element that occurs in trace amounts in Earth’s crust—contained in ancient marine sediments they recovered from Yukon, Canada. Very few processes can strongly fractionate Tl isotopes, that is, partition them in ways that result in different ratios.

The strongest fractionations today occur in deep marine ferromanganese deposits. O2 must accumulate in deep marine waters to stabilize these deposits, according to Ostrander. Thallium isotope ratios in the new study were rarely strongly fractionated, meaning these O2-dependent deepwater deposits were also rare.

“We do find some evidence of O2 building up in the deep ocean, but only for very brief periods of time,” Ostrander said. “Even at the youngest end of our dataset, the ocean seems to plunge back into an episode of widespread anoxia.”

 

Read the full story by Brian Maffly in @ The U. 

On the same team

September 3, 2025

On The Same Team

September 3, 2025

Safety regulations are often treated with an air of annoyance by those required to follow them. A roadblock to hurdle, yet another extra step that must be taken to get where they want to be.

Brandon Newell

But the truth is that every one of those regulations exists due to a tragedy that occurred without it. Brandon Newell cannot stress this importance enough: that safety rules are in place to protect workers, like guardrails. Those who enforce those rules are defenders, part of the team working towards the same goal of getting everyone home safe at the end of the day.

Newell got his start in safety working at Hill Air Force Base where he would take on the role of inspecting any explosives the base would be working with. He was simultaneously using his GI bill to finance his education at Weber State University in Ogden, the combination paving a natural road that led him to the Environmental Health & Safety (EHS) Office here at the U. Since then, he has worn many hats at the EHS, from lab inspector to occupational safety specialist to his current position managing the occupational safety team. 

The rigorous work this team does may come as a surprise, as the U rarely makes the news in terms of these sorts of accidents. This is the greatest irony of work within safety. The more efficiently it is carried out, the less important it seems as nothing is going wrong. 

But such prevention is constantly carried out. As one of many examples of something they’ve caught, Newell describes that “there are many peroxide forming chemicals that can crystallize and explode upon contact when they get old. Doing that on a recurring basis over the last five to seven -years. . . lab personnel have that hazard at the forefront of their minds.” 

It may not lead to the most exciting story headlines, but it’s far more preferable than an injured student, faculty or staff member.

Silent stories like those peroxides happen across campus, from engineering workshops to research labs, to simply walking around campus. To pursue further prevention, the EHS organizes a “Walk After Dark” event every year, bringing all students who wish to participate to jaunt around campus and identify any areas of issue. If there are lights out, damaged railings or lighting needed around potential tripping hazards, EHS wants to know about it. The annual event  symbolizes the EHS’s goals and values: to work together with students to create a safe campus environment.

Brandon Newell closes by stating that “we’re on the same team. We don’t enjoy having to be the people that are forcing compliance, forcing regulations. These are your rights, and we’re here to help make sure that your rights are not violated.”

by Michael Jacobsen

This is the third in a series of periodic spotlights on staff who work in the Department of Environmental Health and Safety at the University of Utah. You can read more about safety and wellness, under the direction of David Thomas in the College of Science here. Read the first story in the series about Christin Torres here, and the second story about Emily O’Hagan here.