Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ammonia-loving archaea win landslide majority

21.08.2006
A genetic analysis of soil samples indicates that a group of microorganisms called crenarchaeota are the Earth's most abundant land-based creatures that oxidize ammonia, according to an international team of researchers from Norway, Germany, United Kingdom and the United States.

Soil microbes, in a process known as nitrification, combine ammonia with oxygen to form nitrates, which are used as nutrients by plants.

"Ammonia oxidation is an important step in the nitrogen cycle that was believed for the last 100 years to be solely performed by bacteria," says Christa Schleper, full professor of Molecular biology of Archaea at University Bergen, Norway.

The discovery was made possible by a combination of different techniques ranging from molecular biology, biochemistry to metagenomics. Using a novel sequencing technique and bioinformatics tools, Stephan C. Schuster, associate professor of biochemistry and molecular biology at Penn State, and his co-workers accurately measured the quantities of active bacteria and archaea in the complex mixtures of soil organisms. The international research team reports their findings in today's (Aug. 17) issue of Nature.

Archaea are single-celled microbes that, along with bacteria, comprise a category of small organisms whose genetic material, or DNA, is not stored in a nucleus (as it is in animals and plants). Crenarchaeota, which belong to the archaea, are found in various habitats, including soil.

"We think crenarchaeota in soil gain their energy from oxidizing ammonia," said Schuster. "But we don't know yet if they can also gain energy by other means. The bacterial counterparts can only do ammonia (and urea) oxidation, nothing else."

During a recent study of a collection of genes in microorganisms, researchers had stumbled on a particular gene, which is responsible for the production of a key enzyme used for the oxidation of ammonia.

The gene was subsequently found in a marine strain of archaea that uses ammonia as its sole source of energy. Researchers examined soil samples from 12 pristine and agricultural lands across three climatic zones to see if such ammonia-oxidizing microorganisms were present in terrestrial ecosystems as well.

"We measured the abundance of the particular crenarchaeota gene alongside the same type of gene from bacteria," explains Schleper.

The tally suggested that copies of the archaeal gene in the soil samples were up to 3,000 times more abundant than copies of the bacterial gene. High amounts of lipids specific to crenarchaeota confirmed the organism's presence.

At Penn State, Schuster used a novel technique to directly sequence only the transcribed portion of the genomes from soil organisms, thus giving proof that crenarchaeota are in fact active and not just dormant residents in the soil.

Crenarchaeotal gene counts also do not change with soil depth, while bacterial gene counts drop significantly as one goes deeper.

"It might mean that they can oxidize ammonia at least with less oxygen and probably also with less ammonia, but we don't know for sure. Our data clearly say, that the archaea are more versatile in their life style than bacteria," says Schuster, also a researcher at Penn State's Centers for Infectious Disease Dynamics and Comparative Genomics and Bioinformatics.

Despite their abundance, it is not yet clear if crenarchaeota oxidize more ammonia than regular bacteria, and what that might mean for the ecological impact of ammonia oxidation, or the nitrogen cycle. We will have to study the nitrification activity of archaea and their underlying biochemistry, says Schleper, who initiated the study.

"Perhaps the measured amounts of greenhouse gases such as nitric oxide and nitrous oxide are not produced by bacteria, but by a very different group of organisms, namely archaea," said Schleper. "But it is not clear, if and in what amounts the archaea form these gases as byproducts. This is only known from some of the respective bacteria," Schleper adds.

Amitabh Avasthi | EurekAlert!
Further information:
http://www.psu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>