Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Zooming in on cells

This image, taken with atomic force microscopy, shows E. coli bacteria after they have been exposed to the antimicrobial peptide CM15. The peptides have begun destroying the bacteria’s cell walls.  Image: Georg Fantner
This image, taken with atomic force microscopy, shows E. coli bacteria after they have been exposed to the antimicrobial peptide CM15. The peptides have begun destroying the bacteria’s cell walls. Image: Georg Fantner

Abstract:
New microscopy technique offers close-up, real-time view of how proteins kill bacteria

By Anne Trafton, MIT News Office

Zooming in on cells

Cambridge, MA | Posted on March 15th, 2010

For two decades, scientists have been pursuing a potential new way to treat bacterial infections, using naturally occurring proteins known as antimicrobial peptides (AMPs) that kill bacteria by poking holes in their cell membranes. Now, MIT scientists have recorded the first real-time microscopic images showing the deadly effects of AMPs in live bacteria.

Researchers led by MIT Professor Angela Belcher modified an existing, extremely sensitive technique known as high-speed atomic force microscopy (AFM) to allow them to image the bacteria in real time. Their method, described in the March 14 online edition of Nature Nanotechnology, represents the first way to study living cells using high-resolution images recorded in rapid succession.

Using this type of high-speed AFM could allow scientists to study how cells respond to other drugs and to viral infection, says Belcher, the Germeshausen Professor of Materials Science and Engineering and Biological Engineering and a member of the Koch Institute for Integrative Cancer Research at MIT.

It could also be useful in studying cell death in mammalian cells, such as the nerve cell death that occurs in Alzheimer's patients, says Paul Hansma, a physics professor at the University of California at Santa Barbara who has been developing AFM technology for 20 years. "This paper is a highly significant advance in the state-of-the-art imaging of cellular processes," says Hansma, who was not involved in the research.

High speed

Atomic force microscopy, invented in 1986, is widely used to image nanoscale materials. Its resolution (about 5 nanometers) is comparable to that of electron microscopy, but unlike electron microscopy, it does not require a vacuum and thus can be used with living samples. However, traditional AFM requires several minutes to produce one image, so it cannot record a sequence of rapidly occurring events.

In recent years, scientists have developed high-speed AFM techniques, but haven't optimized them for living cells. That's what the MIT team set out to do, building on the experience of lead author Georg Fantner, a postdoctoral associate in Belcher's lab who had worked on high-speed AFM at the University of California at Santa Barbara.

Atomic force microscopy makes use of a cantilever equipped with a probe tip that "feels" the surface of a sample. Forces between the tip and the sample can be measured as the probe moves across the sample, revealing the shape of the surface. The MIT team used a cantilever about 1,000 times smaller than those normally used for AFM, which enabled them to increase the imaging speed without harming the bacteria.

The measurements are performed in a liquid environment, another critical factor in keeping the bacteria alive.

With the new setup, the team was able to take images every 13 seconds over a period of several minutes following treatment with an AMP known as CM15. They found that AMP-induced cell death appears to be a two-step process: a short incubation period followed by a rapid "execution." They were surprised to see that the onset of the incubation period varied from 13 to 80 seconds.

"Not all of the cells started dying at the exact same time, even though they were genetically identical and were exposed to the peptide at the same time," says Roberto Barbero, a graduate student in biological engineering and an author of the paper.

Most AMPs act by puncturing bacterial cell membranes, which destroys the delicate equilibrium between the bacterium and its environment. Others appear to target machinery inside the cell. There has been a great deal of interest in developing AMPs as drugs that could supplement or replace traditional antibiotics, but none have been approved yet.

Until a few years ago, it was thought that bacteria could not become resistant to AMPS, but recent studies have shown that they can. The new MIT work could help researchers understand how that resistance develops.

The research was funded by an Erwin-Schrodinger Fellowship, the National Institutes of Health, Army Research Office and Austrian Research Promotion Agency.

####

About MIT
The mission of MIT is to advance knowledge and educate students in science, technology and other areas of scholarship that will best serve the nation and the world in the 21st century — whether the focus is cancer, energy, economics or literature.

For more information, please click here

Copyright © MIT

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Nanoscale Mirrored Cavities Amplify, Connect Quantum Memories: Advance could lead to quantum computing and the secure transfer of information over long-distance fiber optic networks January 28th, 2015

Detecting chemical weapons with a color-changing film January 28th, 2015

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables January 28th, 2015

Nanomedicine

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Made-in-Singapore rapid test kit detects dengue antibodies from saliva: IBN's MedTech innovation simplifies diagnosis of infectious diseases January 29th, 2015

Iranian Researchers Planning to Produce Edible Insulin January 28th, 2015

Nanoparticles that deliver oligonucleotide drugs into cells described in Nucleic Acid Therapeutics January 28th, 2015

Announcements

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Tools

Hiden Gas Analysers at PITTCON 2015 | Visit us on Booth No. 1127 January 29th, 2015

Advantest to Exhibit at SEMICON Korea in Seoul, South Korea February 4-6 Showcasing Broad Portfolio of Semiconductor Products, Technologies and Solutions January 29th, 2015

Park Systems Announces Innovations in Bio Cell Analysis with the Launch of Park NX-Bio, the only 3-in-1 Imaging Nanoscale Tool Available for Life Science Researchers January 29th, 2015

2015 Nanonics Image Contest January 29th, 2015

Nanobiotechnology

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Spider electro-combs its sticky nano-filaments January 28th, 2015

Nanoshuttle wear and tear: It's the mileage, not the age January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE