Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Checking how cells grow

24.04.2003


New research dismisses a widely held assumption about how cells grow



Research published today in Journal of Biology challenges an assumption about cell growth that underpins modern cellular biology. Ian Conlon and Martin Raff, of University College London, show that mammalian cells do not regulate their size in the way scientists have assumed they do since the 1970s.
Conlon and Raff conducted a series of experiments, using Schwann cells from the sciatic nerve of rats, to establish how mammalian cells control their size and ‘decide’ when to divide. This processes of cell size, growth and division has been widely studied in yeast for thirty years, and many aspects are the same in the two types of cell. Both yeast and mammalian cells are known to be able to maintain a constant average size as they grow and divide. It has therefore been assumed that the ‘checkpoints’ yeast cells use to ensure that they divide when they reach the correct size are mirrored by checkpoints in mammalian cells, but that assumption had not been tested experimentally - until now.

Using precise measurements, Conlon and Raff found key differences in the ways yeast and mammalian cells grow. Yeast cells grow exponentially, doubling in size over a fixed time period, but mammalian cells grow in a linear way, getting larger by the same amount each day; this means that the rate at which mammalian cells grow is the same regardless of the cell’s size, whereas in yeast big cells grow faster than small ones.



Previous research had shown that when moved to a nutrient-rich environment, yeast cells adjust quickly - within one cycle of growth and division. The average size of the cells increases when there are more nutrients available – so, yeast uses cell-size checkpoints to determine how large the cell should be before it divides.

It had been assumed that mammalian cells also use cell-size checkpoints. But Conlon and Raff found that when mammalian cells were moved to a nutrient-rich environment, it took approximately six divisions before cells grew to the average size they expected. This led them to conclude that mammalian cells do not use checkpoints based on their size to determine when to divide. Instead, Conlon and Raff suggest that mammalian cells ‘talk’ to each other, using extracellular signalling, to determine how large they should grow and when they should divide. “Animal cells hardly do anything without signals from other cells” says Raff.

The new research makes clear that there are important differences between the way yeast and mammalian cells coordinate cell growth and size. These differences make sense biologically. Yeast is a single-celled organism - cells are independent of each other and can grow and divide as fast as the nutrients in their environment can support. Animal cells are part of a larger organism, so their growth affects the good of the whole animal, and it makes good biological sense that this is controlled by signals from other cells.

Understanding cell growth and proliferation is of profound importance for biology and has implications for tackling disease, including cancer.

Grace Baynes | BioMed Central Limited
Further information:
http://jbiol.com/content/2/1/7

More articles from Life Sciences:

nachricht Cells migrate collectively by intermittent bursts of activity
30.09.2016 | Aalto University

nachricht The structure of the BinAB toxin revealed: one small step for Man, a major problem for mosquitoes!
30.09.2016 | CNRS (Délégation Paris Michel-Ange)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.

Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Paper – Panacea Green Infrastructure?

30.09.2016 | Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

 
Latest News

First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

30.09.2016 | Materials Sciences

New Technique for Finding Weakness in Earth’s Crust

30.09.2016 | Earth Sciences

Cells migrate collectively by intermittent bursts of activity

30.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>