Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How fast does a stressed cell react?

27.05.2008
When subjected to stress, such as an alteration to its environment, a cell reacts more or less rapidly in order to ensure its survival. In yeast, this takes place through a series of reactions that are well-known, but whose dynamics had never been studied.

This has now been done by CNRS researcher Pascal Hersen (1) and the team led by Sharad Ramanathan at the Center for Systems Biology (Harvard University). Using a simple and innovative measuring device that they developed, the researchers have confirmed the hypothesis that above a certain stimulation frequency, the yeast cell no longer responds to osmotic stress (2).

They are now able to measure the rate of reaction to such stress, and above all, modify the reaction rate by eliminating certain genes. This work opens up new prospects for biological engineering. The idea is to construct cells with novel biological functions and whose dynamics can be controlled. These findings have been published on line on the web site of the journal /PNAS/.

Place a little salt on a cell and it immediately shrinks. This phenomenon is caused by the difference in salinity inside and outside the cell. To restore equilibrium between the concentrations, the cell releases some water, which reduces its size. In order to return to normal size, the cell undergoes a series of reactions that are essential for the efficient working of its regulation and adaptation processes. In the yeast Saccharomyces cerevisiae, a model eukaryotic (3) system, such a cascade has been well described. However, its dynamics remain poorly understood. A cell needs to react at the right rate in order to ensure its survival. It is therefore essential to understand the dynamics of cell response to environmental stress.

... more about:
»Dynamic »Membrane »reaction »yeast

To this end, Pascal Hersen, CNRS researcher at the Complex Systems and Matter Laboratory (CNRS / Université Paris 7), and his US colleagues decided to study how and at what rate yeast responds and adapts to environmental stress. Using a simple device that makes it possible to follow the behavior of individual cells, they created an environment which periodically brings about disequilibrium. In this way they were able to determine the dynamic properties of cell response.

Their first observation was that when the frequency is too high, the size of the cells doesn't change. There simply isn't enough time for the transfer of water through the cell membrane to take place. On the other hand, for lower frequencies (input of disequilibrium every 10 seconds), the cells shrink and swell periodically, faithfully following the fluctuations of the disequilibrium. However, in this range of frequencies, there isn't enough time for the cascade of reactions to be activated between two cycles. There is thus a decoupling between the mechanical response and the biological response. It is only when the period is more than around ten minutes that the biological reactions are activated and follow one another 'naturally', while at the same time being coupled to the mechanical response of the cell. This frequency is therefore characteristic of the response dynamics in yeast, which is unable to faithfully follow changes in its environment that are too rapid, i.e. a period of less than ten minutes.

Finally, by eliminating certain genes from the yeast, the researchers showed that this cascade can be significantly slowed down. They now hope to understand how the quantity and nature of the proteins affects the dynamics of these reactions, and how they might eventually be able to speed them up or slow them down. Being able to manipulate them in this way opens up new prospects in synthetic biology (4) for the design of cells with novel functions, whose dynamics of response to stress can be controlled.

(1) Unité Matière et systèmes complexes (MSC, CNRS / Université Paris 7).

(2) Osmotic stress is caused by a difference in concentration of solute (such as salt) on either side of the cell membrane. Osmosis is the name given to the phenomenon of a return to equilibrium by diffusion of water through the membrane.

(3) A living organism which has a nucleus separated from the cytoplasm by a membrane and containing DNA.

(4) Synthetic biology is the engineering of living organisms. It consists in synthesizing complex systems based on biology which carry out functions that don't exist in nature.

Julien Guillaume | alfa
Further information:
http://www.cnrs-dir.fr
http://www.pnas.org/cgi/content/abstract/0710770105v1

Further reports about: Dynamic Membrane reaction yeast

More articles from Life Sciences:

nachricht Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University

nachricht Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>