Free Newsletters - Space - Defense - Environment - Energy
..
. Medical and Hospital News .




INTERN DAILY
3-D printed microscopic cages confine bacteria in tiny zoos for the study of infections
by Staff Writers
Austin TX (SPX) Oct 09, 2013


The researchers use a novel 3-D printing technology to build homes for bacteria at a microscopic level. The resulting structures (imaged in red through confocal fluorescence) can be of almost any shape or size, and can be moved around in relationship to other structures containing bacterial microcommunities (imaged in green). Image courtesy of Jason Shear.

By caging bacteria in microscopic houses, scientists at The University of Texas at Austin are studying how communities of bacteria, such as those found in the human gut and lungs, interact and develop infections.

In a recent experiment they demonstrated that a community of Staphylococcus aureus, which can cause some skin infections, became more resistant to antibiotics when it was contained within a larger community of Pseudomonas aeruginosa, a bacteria involved in various diseases, including cystic fibrosis.

The work was published this week in the Proceedings of the National Academy of Sciences.

The researchers use a novel 3-D printing technology to build homes for bacteria at a microscopic level. Their method uses a laser to construct protein "cages" around bacteria in gelatin. The resulting structures can be of almost any shape or size, and can be moved around in relationship to other structures containing bacterial microcommunities.

The method should enable an entirely new class of experiments that better approximate the conditions that bacteria encounter in actual biological environments, such as those in the human body.

"It allows us to basically define every variable," said Jodi Connell, a postdoctoral researcher in the College of Natural Sciences. "We can define the spatial features on a size scale that's relevant to what a single bacterium feels and senses. We can also much more precisely simulate the kinds of complex bacterial ecologies that exist in actual infections, where there typically aren't just one but multiple species of bacteria interacting with each other."

The method begins with a gelatin-based reagent that has a few key features. Bacteria can live and reproduce comfortably within it. When warm it's a liquid solution but at room temperature becomes firm like JELL-O. And it has within it photosensitive molecules that cause gelatin molecules to react and link together when struck by laser light.

The bacteria are put in the solution, and when the solution cools, the bacteria become fixed in place. Connell and her colleagues, including Jason Shear, professor of chemistry, and Marvin Whiteley, professor of molecular biosciences, identify which bacteria they want to cage and in what shape. Then they fire the laser, using a chip adapted from a digital movie projector to project a two-dimensional image into the gelatin. Wherever it focuses, a solid matrix forms.

"Then we do another layer, and another, and so on, building up," said Shear.

"It's very simple. We're basically making pictures and stacking them up into 3-D structures, but with incredible control. Think about the thickness of a hair on your head, and take 1 percent of that, and then take about a quarter of that. That's about the size of our laser when it's brought to its smallest point."

After the structure is completed, the bacteria can be fed nutrients and allowed to reproduce within a confined space to a controlled density. The scientists can take other caged microcommunities and put them close enough together for the communities to signal to each other. They can even wash away the excess gelatin, arrest the growth of the bacteria and store them for later transport to labs in other parts of the world.

"What's key is these structures aren't just controllable in terms of their geometries; they're also very bio-friendly," said Shear.

"The walls that we make out of these protein molecules are linked together tightly enough to prevent the bacteria from escaping, but they are porous enough to be chemically permissive. Nutrients can come in. Waste can go out. Signals can be exchanged. They're trapped in these tiny houses, but they function like they do in biological environments."

Shear said the new technique should enable a vast range of experiments. Growth can be arrested at any point to do gene expression analyses of bacteria, to see which genes are turned on or off in response to conditions. Multiple bacteria can be forced to interact in different configurations, at different densities, over varying timescales.

Bacteria such as Staph and Pseudomonas can be arranged in a "core-and-shell," with a core of Staph surrounded by a shell of Pseudomonas, to see what happens when they're both confronted by an unwelcome intruder.

"These are really common bacteria that are often found together in infections, and it makes sense that they would have mechanisms to sense each other," said Shear. "What the technology allows us to do is put them in conversation with each other, in very precise ways, and see what happens. In this case the Staph sensed the Pseudomonas, and one result was that it became more resistant to the antibiotics."

Among the long-term goals are to use the insights gleaned from such experiments to better combat infections in humans.

"Think about a hospital, which we know is not a good place to be to avoid infections," said Shear. "There are studies that seem to indicate that infections are transmitted by very small microcolonies of bacteria, which are likely transported by equipment or staff from one part of the hospital to another.

"We currently know little about how this is happening. How many cells does it take? Do these microcommunities become particularly virulent or antibiotic resistant precisely because they're small, and then in turn change the properties of bacteria on our skin or in our bodies? Now we have a means to start asking these questions much more broadly."

.


Related Links
University of Texas at Austin
Hospital and Medical News at InternDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

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




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



International Conference on Protection of Materials and Structures From Space Environment



INTERN DAILY
Outside View: First Obamacare, then a single-payer system
College Park, Md. (UPI) Sep 27, 2013
Republicans must live with Obamacare. They have few prospects for electing 60 senators needed to repeal the law and, unless they work to make it more palatable, something they have few ideas to accomplish - the country is headed for socialized medicine. Obamacare seeks to substantially reduce the ranks of uninsured. - It requires businesses with more than 50 employees to provid ... read more


INTERN DAILY
Smart smoke alarm can speak, warn of smoke, carbon monoxide

European satellites included in test of search-and-rescue system

Indonesia to boost patrols against people smugglers

'Ship in a bottle' detects dangerous vapors

INTERN DAILY
Orbcomm Acquires The SENS Asset Tracking Operation

No more Glonass-M satellite launches planned before end of year

Astrium down selected for MOJ electronic tagging contract

Lockheed Martin GPS 3 Satellite Prototype Integrated With Raytheon OCX Ground Control Segment

INTERN DAILY
Council of Europe attacks genetic procedure

Ancient sagas show Vikings more social, less warlike

Einstein's genius put down to 'well-connected' brain halves

Roma families face wholesale expulsion from France

INTERN DAILY
Ants more closely related to bees than to most wasps

Unlocking Biology With Math

Kenya seizes 4 tonnes of ivory as elephant slaughter surges

Dutch fishermen give vanishing eels new lease of life

INTERN DAILY
Projected climate change in West Africa not likely to worsen malaria situation

HIV infections plummet since 2001: UN

Disarming HIV With a "Pop"

AIDS epidemic's end by 2030 seen: UN official

INTERN DAILY
US report says little progress on China rights

Mexican officials won't meet Dalai Lama: Tibetan group

US Chinatowns risk disappearance: study

Chinese court agrees to hear Bo Xilai appeal

INTERN DAILY
Accused Silk Road mastermind to be sent to New York for trial

Somali pirate suspects deny 'attack' on Spanish anti-pirate ship: court

US authorities shut Silk Road website, arrest owner

INTERN DAILY
Kerry seeks to reassure Asian leaders over US default

Australia should branch out beyond mining: report

IMF cuts China 2013 growth forecast to 7.6%

Walker's World: Spain's double-edged recovery




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal 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. 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