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 Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>