Subscribe to our free daily newsletters
  Energy News  




Subscribe to our free daily newsletters



TECH SPACE
Stiff fibers spun from slime
by Staff Writers
Munich, Germany (SPX) Oct 19, 2017


Slimy hunting weapon: Velvet worms, which look like caterpillars with short legs, capture prey with a secretion that forms polymer threads as the prey struggles to free itself.

Some animals produce amazing materials. Spider silk, for example, is stronger than steel. Mussels secrete byssus threads, which they use to cling tightly to stones under water. The material secreted by velvet worms is no less impressive.

These small worm-like animals, which look like a cross between an earthworm and a caterpillar, spray a sticky liquid to ward off enemies or catch prey that is particularly deadly for prey such as woodlice, crickets and spiders: As soon as they try to wriggle out of the slimy threads, their struggles cause the threads to harden, leaving no hope of escape.

"The shear forces generated by the prey's struggles cause the slime to harden into stiff filaments," explains Alexander Bar, a doctoral student at the University of Kassel, who is studying under the velvet-worm expert Georg Mayer. In order to investigate the slime of an Australian velvet worm species, the biologist worked closely with researchers from the Max Planck Institute of Colloids and Interfaces in Potsdam.

The chemist Stephan Schmidt, for example, now a junior professor at Heinrich Heine University in Dusseldorf, helped to elucidate the nanostructure of the slime. A research group headed by biochemist Matt Harrington in the Biomaterials Department of the Potsdam Institute focused on other questions concerning the chemical composition and molecular processing. The interdisciplinary group of scientists was particularly interested in how the composition and structure of the secretion changes during thread formation.

Slimy mix of proteins and fatty acids
"We had already known that the slime consists mainly of large protein molecules and fatty acids," Alexander Bar says. At the Max Planck Institute in Potsdam, the researchers discovered that the proteins and lipids combine to form tiny globules. "Velvet worms produce the protein and fat molecules as well as other components separately", Bar explains.

"Outside the gland cells, the nanoglobules then form independently to create the thread-forming and adhesive properties." The globules are formed with remarkable precision in that they are uniform in shape and always around 75 nanometres in diameter.

Velvet worms store their liquid weapon until it is needed. They then shoot the slime at their prey or foe through two glands located on either side of their head by means of muscular contractions. "At first the sticky consistency does not change," Bar says. "However, as soon as the prey begins to struggle, shear forces act on the slime to rupture the nanoglobules."

Vibrational spectroscopy studies in Potsdam showed that proteins and fatty acids separate in the process. "Whereas the proteins form long fibres in the interior of the slime, the lipid and water molecules are displaced to the outside and form a kind of sheath," Bar explains. The researchers also found that the protein strand inside has a tensile stiffness similar to that of Nylon. This explains the remarkable performance of the filaments.

Polymerized threads dissolve in water again
Further experiments showed that the polymerized slime threads can be dissolved in water again within a few hours of drying. "The astonishing thing for us was that the proteins and lipids evidently mix again to form the same nanoglobules we had already found in the original slime," Matt Harrington says. The newly formed protein-lipid globules were even similar in size to those in the natural secretion. "Evidently, a mechanism of self-organization is at work which we do not yet fully understand," Harrington says.

Another startling discovery was that sticky threads can be drawn again from the recovered slime. And they behaved exactly like freshly secreted velvet-worm secretion under the influence of shear forces: they hardened. "This is a nice example of a fully reversible and indefinitely repeatable regeneration process," says Matt Harrington.

Intriguingly, this is all accomplished with biomolecules and at normal ambient temperatures. Velvet worms could therefore serve as a model for manufacturers of synthetic polymers and could conceivably teach them a lot about the sustainable production of synthetic materials.

Harrington agrees. The biochemist can well imagine that one day we will be able to synthesize macromolecules for industrial applications in a similar manner based on renewable raw materials. In the case of spider silk, it has already been possible to produce analogous proteins industrially and to supply the fibres produced from them to the garment industry.

How are proteins and lipid molecules separated?
A polymer that dissolves in water, like the solidified threads of velvet worms, would probably be impractical. But the principle could generate new inspirations in materials science, Matt Harrington believes. "At the moment, the first step is to understand the mechanisms better," says the biomaterials specialist, who has now begun a professorship at McGill University in Montreal.

For example, the scientists are interested in why mechanical shear forces cause the proteins to separate from the lipid molecules in the first place. They also want to determine the factors that govern the reversible formation of nanoglobules of uniform size. Another unanswered question is how the protein units combine to produce rigid fibres without forming fixed chemical bonds, says Max Planck researcher Harrington.

Research paper

TECH SPACE
Study shows how rough microparticles can cause big problems
Raleigh NC (SPX) Oct 18, 2017
New research from North Carolina State University, MIT and the University of Michigan finds that the surface texture of microparticles in a liquid suspension can cause internal friction that significantly alters the suspension's viscosity - effectively making the liquid thicker or thinner. The finding can help address problems for companies in fields from biopharmaceuticals to chemical manufactu ... read more

Related Links
Max-Planck-Gesellschaft
Space Technology News - Applications and Research


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TECH SPACE
How solar peaker plants could replace gas peakers

Transparent solar technology represents 'wave of the future'

Clean Energy Collective Starts Construction on SCE and G Community Solar Facilities

SCE monopoly abuse of power prompts the necessity of off-grid inventions

TECH SPACE
Electricity from shale gas versus coal

North America helped drive revenue for Halliburton

Oil prices diverge on competing trends

Gas has environmental benefits, with caveats

TECH SPACE
Geologic evidence is the forerunner of ominous prospects for a warming earth

'Plan B': Seven ways to engineer the climate

British government unveils green spending plans

As Paris climate goals recede, geoengineering looms larger

TECH SPACE
Sulfur may be key for safe rechargeable lithium batteries

The blob that ate the tokamak

Loops of liquid metal can improve future fusion power plants

A new miniature solution for storing renewable energy

TECH SPACE
Separating methane and CO2 will become more efficient

Converting carbon dioxide to carbon monoxide using water, electricity

Breaking down stubborn cellulose

Breakthrough in direct activation of CO2 and CH4 into liquid fuels and chemicals

TECH SPACE
Lyft gets $1 bn from Google parent to rev up challenge to Uber

Baidu to hit the road with self-driving bus

President Duterte threatens iconic Philippine 'jeepney'

Norway seeks 'Tesla tax' on electric cars

TECH SPACE
Little growth observed in India's methane emissions

India to close colonial-era military farms

Smallscale farmers try to solve Amazon's big problems

Genetically boosting the nutritional value of corn could benefit millions

TECH SPACE
The drop that's good to the very end

Study shows how rough microparticles can cause big problems

Chemical treatment improves quantum dot lasers

Missing link between new topological phases of matter discovered




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement