Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What's shaped like a pear and has two genomes? Check the pond

30.08.2006
Researchers sequence the macronuclear genome of Tetrahymena thermophila, a model eukaryote

If you could peer microscopically into the closest freshwater pond, you'd hesitate before dipping a toe. Amid the murky water, you'd probably notice an oddly furry, pear-shaped organism gliding along--and gobbling up everything in its path.

This tiny predator has a big name--Tetrahymena thermophila--and a big fan club among scientists, as a star organism for research into how cells work.

Scientists have now sequenced, assembled, and analyzed T. thermophila's macronuclear genome. Their work, reported in today's issue of Public Library of Science (PLoS) Biology, explains the organism's impressive versatility. Rather than dividing labor into several types of cells, as humans and other multicellular organisms do, T. thermophila divides its activities, either into different places inside a cell or by changing the cell over time. It is a master multi-tasker.

... more about:
»Tetrahymena »pond

"This organism is a true generalist," says evolutionary biologist Jonathan A. Eisen, who led the Tetrahymena project while at The Institute for Genomic Research (TIGR) and is now at the University of California, Davis. "Whatever this unicell touches with its hairlike projections, it will try to eat. If it does not bump into anything, the organism will seek out food with diverse sensory systems. It can protect itself from radiation and other threats and also can fight back against competitors and predators. In short, versatility is its strength. Now, we can understand how this versatility works."

It takes plenty of genes. In fact, T. thermophila has roughly 25,000 genes--nearly as many as humans do. Although the organism is single-celled, it contains a genetic repertoire of seemingly more complex organisms. It shares, with humans and other animals, many genes and processes typically absent in single-celled organisms. That means Tetrahymena may be an ideal model organism for studies of the processes these genes encode.

In the new study, genome analysis showed that one way that Tetrahymena adapts to diverse environments via gene duplication, a process that allows organisms to diversify pre-existing genes and adapt them for new functions. In the case of Tetrahymena, duplications appear to be concentrated in genes involved in sensing and responding to environment. From a small number of proteases (enzymes that degrade proteins), for instance, Tetrahymena has built an eating machine that allows it to digest nearly any protein it encounters.

Among its most quirky features, Tetrahymena has, inside each of its cells, two distinct nuclei, each with a different genome. Inside one nucleus, the "micronuclear" genome is reserved for sex and reproduction, remaining genetically silent during growth. Inside the second, working nucleus is the "macronuclear" genome, which expresses genes that govern behavior.

The current study sequenced the macronuclear genome, an impressively packaged bunch of coding genes, free of so-called junk DNA (noncoding sequences and other extraneous genetic elements) that litter the genomes of many organisms.

"Publication of the Tetrahymena genome marks the culmination of a remarkable collaboration within the research community," said Anthony Carter, Ph.D., of the National Institute of General Medical Sciences (NIGMS), which co-funded the project with the National Science Foundation (NSF). "Tetrahymena has a long and eminent history in the world of cell biology, and publication of its genome is likely to lead to further fundamental insights into how cells work."

Throughout the project, Eisen says, collaboration between researchers has been critical, including work by co-author Eduardo Orias of the University of California-Santa Barbara. The team emphasized open access to data, providing the genome sequence data to outside researchers, without restriction, since the project began in 2003. As a result, Tetrahymena researchers have already published dozens of studies making use of the genomic data. In addition to releasing the sequence data early on TIGR's website (www.tigr.org/tdb/e2k1/ttg/index.shtml) and via Genbank, the project also underwrote the creation of a major free community resource: The Tetrahymena Genome Database (TGD; http://ciliate.org/), headed by Mike Cherry at Stanford University. The publication in the open access journal PLoS Biology represents a commitment to free and open access to scientific literature as well. Now anyone, anywhere in the world, can read about the genome of this fascinating organism before meeting it in the local pond.

Kathryn Brown | EurekAlert!
Further information:
http://www.tigr.org/

Further reports about: Tetrahymena pond

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>