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 Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>