Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The 'intraterrestrials': New viruses discovered in ocean depths

01.04.2015

Viruses infect methane-eating archaea beneath the seafloor

The intraterrestrials, they might be called.


The scientists used the deep submergence vehicle Alvin to retrieve sea-floor samples.

Credit: David Valentine

Strange creatures live in the deep sea, but few are odder than the viruses that inhabit deep ocean methane seeps and prey on single-celled microorganisms called archaea.

The least understood of life's three primary domains, archaea thrive in the most extreme environments on the planet: near hot ocean rift vents, in acid mine drainage, in the saltiest of evaporation ponds and in petroleum deposits deep underground.

Virus in the deep blue sea

While searching the ocean's depths for evidence of viruses, scientists have found a remarkable new one, a virus that seemingly infects archaea that live beneath the ocean floor.

The researchers were surprised to discover that the virus selectively targets one of its own genes for mutation, and that this capacity is also shared by archaea themselves.

The findings appear today in a paper in the journal Nature Communications.

The project was supported by a National Science Foundation (NSF) Dimensions of Biodiversity grant to characterize microbial diversity in methane seep ecosystems. Dimensions of Biodiversity is supported by NSF's Directorates for Biological Sciences and Geosciences.

New information about life in ocean depths

"Life far beneath the Earth's subsurface is an enigma," said Matt Kane, program director in NSF's Division of Environmental Biology. "By probing deep into our planet, these scientists have discovered new information about Earth's microbes and how they evolve."

"Our study uncovers mechanisms by which viruses and archaea can adapt in this hostile environment," said David Valentine, a geoscientist at the University of California Santa Barbara (UCSB) and co-author of the paper.

The results, he said, raise new questions about the evolution and interaction of the microbes that call the planet's interior home.

"It's now thought that there's more biomass inside the Earth than anywhere else, just living very slowly in this dark, energy-limited environment," said paper co-author Sarah Bagby of UCSB.

Using the submersible Alvin, Valentine and colleagues collected samples from a deep-ocean methane seep by pushing tubes into the ocean floor and retrieving sediments.

The contents were brought back to the lab and fed methane gas, helping the methane-eating archaea in the samples to grow.

When the team assayed the samples for viral infection, they discovered a new virus with a distinctive genetic fingerprint that suggested its likely host was methane-eating archaea.

Genetic sequence of new virus holds the key

The researchers used the genetic sequence of the new virus to chart other occurrences in global databases.

"We found a partial genetic match from methane seeps off Norway and California," said lead author Blair Paul of UCSB. "The evidence suggests that this viral type is distributed around the globe in deep ocean methane seeps."

Further investigation revealed another unexpected finding: a small genetic element, known as a diversity-generating retroelement, that accelerates mutation of a specific section of the virus's genome.

Such elements had been previously identified in bacteria and their viruses, but never among archaea or the viruses that infect them.

"These researchers have shown that cutting-edge genomic approaches can help us understand how microbes function in remote and poorly known environments such as ocean depths," said David Garrison, program director in NSF's Division of Ocean Sciences.

While the self-guided mutation element in the archaea virus resembles known bacterial elements, the researchers found that it has a divergent evolutionary history.

"The target of guided mutation--the tips of the virus that make first contact when infecting a cell--is similar," said Paul.

"But the ability to mutate those tips is an offensive countermeasure against the cell's defenses, a move that resembles a molecular arms race."

Unusual genetic adaptations

Having found guided mutation in a virus-infecting archaea, the scientists reasoned that archaea themselves might use the same mechanism for genetic adaptation.

In an exhaustive search, they identified parallel features in the genomes of a subterranean group of archaea known as nanoarchaea.

Unlike the deep-ocean virus that uses guided mutation to alter a single gene, the nanoarchaea target at least four distinct genes.

"It's a new record," said Bagby.

"Bacteria had been observed to target two genes with this mechanism. That may not seem like a huge difference, but targeting four is extraordinary."

According to Valentine, the genetic mutation that fosters these potential variations may be key to the survival of archaea beneath the Earth's surface.

"The cell is choosing to modify certain proteins," he said. "It's doing its own protein engineering. While we don't yet know what those proteins are being used for, learning about the process can tell us something about the environment in which these organisms thrive."

###

Viral DNA sequencing was provided through a Gordon and Betty Moore Foundation grant. The research team also included scientists from the University of California, Los Angeles; the University of California, San Diego; and the U.S. Department of Energy's Joint Genome Institute.

Media Contact

Cheryl Dybas
cdybas@nsf.gov
703-292-7734

 @NSF

http://www.nsf.gov 

Cheryl Dybas | EurekAlert!

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>