Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Algae’s Protein “Tails” Create Motion – and Aid Munching

30.05.2006
When single-celled organisms such as sperm crack their whip-like appendages called flagella, the beating sets them in motion. But in certain colonies of green algae, flagella also boost nutrient uptake, according to surprising new research.

In the early online edition of the Proceedings of the National Academy of Sciences, researchers from the University of Arizona and Brown University explain how flagella allow these algae to get the energy they need to multiply and create colonies – the critical secret that allowed them to evolve into multicellular organisms.


Munching in motion
The beating flagella of a Volvox colony creates a flow of water around it, visible here through the use of miniscule, illuminated plastic beads. The coordinated beating of flagella creates a nutrient-rich environment for the colony. Image: University of Arizona

“This is the first evidence that flagella not only help organisms move, but can help them feed at a rate that allowed them to evolve to a larger size,” said Thomas Powers, an assistant professor of engineering at Brown who studies microorganisms in motion. “This is a critical piece of information, since understanding how one-celled life forms evolve into many-celled ones is a fundamental question in biology.”

The team studied a group of green algae known as the volvocines, organisms so common they can be found in puddles of rain. Biologists study the group, which runs the gamut from single-celled organisms to teeming colonies, to understand how cells differentiate and multiply. But how did the volvocines jump from solo cells to Volvox, a colony of as many as 50,000 cells?

It’s a puzzler of a question, given the size of a Volvox colony and the laws of physics. Bigger organisms need more energy – a lot more energy – to survive. And Volvox is the largest colony that the volvocines make, a giant ball of flagella-waving body guards protecting a small cluster of reproductive cells. When the radius of the spherical colony increases by a factor of two, the area of the sphere increases by a factor of four. So it follows that the energy demands for Volvox would quadruple, too, as it grows.

Yet microscopic organisms such as volvocines get nutrients through diffusion, a process by which bits of food bump into the cell and pass through the cell membrane. Doubling the radius of the colony doubles – not quadruples – the colony’s food intake rate. So a large organism such as a Volvox colony shouldn’t survive because it would demand more energy than passive feeding could supply, a conundrum that researchers refer to as the “bottleneck problem.”

The research team had a hunch that flagella somehow played a role in bringing in nutrients needed for Volvox to grow and survive. Raymond Goldstein, a professor of physics and applied mathematics at the University of Arizona, gathered together a group of scientists with expertise in physics, mathematics, engineering and biology to work on the problem.

The team created a mathematical model that allowed them to calculate how the flagella created a flow of water around the colony and verified this prediction with experimental measurements. Then they used the model to show that the coordinated beating of the flagella concentrated the nutrients just ahead of the moving colony. The colony plows into this nutrient-rich region and leaves a plume of waste in its wake.

So a Volvox colony doesn’t just passively feed, it actively increases the concentration of nutrients around it using its flagella. Put another way, these tiny protein whips not only acts as legs, but also as arms, gathering in food the colony needs to grow and thrive.

Powers, brought in to help with biomechanical theory, said the surprise in the finding is that the nutrient current created by Volvox was proportional to the surface area of the colony. In other words, Volvox met its rapidly increasing demand for nutrients through flagellar beating, allowing the organism to make the multicellular leap.

“Previous models would have predicted that the nutrient demands of Volvox would outstrip the supply,” Powers said. “But we showed that metabolic supply can, in fact, keep up with metabolic demand. The colony beat the bottleneck problem. Its increasing size is actually an advantage, allowing it to create a faster flow of nutrients.”

The National Science Foundation funded the work.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>