Earth Science News  





. Together We Stand: Bacteria Organize To Survive Hostile Zones

File image.
by Staff Writers
Baltimore MD (SPX) Nov 14, 2007
Using an innovative device with microscopic chambers, researchers from four institutions, including Johns Hopkins, have gleaned important new information about how bacteria survive in hostile environments by forming antibiotic- resistant communities called biofilms. These biofilms play key roles in cystic fibrosis, urinary tract infections and other illnesses, and the researchers say their findings could help in the development of new treatments and preventive measures.

"There is a perception that single-celled organisms are asocial, but that is misguided," said Andre Levchenko, assistant professor of biomedical engineering in The Johns Hopkins University's Whiting School of Engineering and an affiliate of the university's Institute for NanoBioTechnology. "When bacteria are under stress which is the story of their lives they team up and form this collective called a biofilm. If you look at naturally occurring biofilms, they have very complicated architecture. They are like cities with channels for nutrients to go in and waste to go out."

With a better understanding of how and why bacteria form biofilms, researchers may be able to disrupt activity in the bacterial communities and block harmful effects on their human hosts. The team's findings were detailed in an article published in the November 2007 issue of the journal Public Library of Science Biology.

In the article, the researchers from Johns Hopkins; Virginia Tech; the University of California, San Diego; and Lund University in Sweden reported on the observation of the bacteria E. coli growing in the cramped conditions of a new microfluidic device. The device, which allows scientists to use nanoscale volumes of cells in solution, contains a series of tiny chambers of various shapes and sizes that keep the bacteria uniformly suspended in a culture medium.

Levchenko and his colleagues recorded the behavior of single layers of cells using real-time microscopy. Computational models validated their experimental results and could predict the behavior of other bacterial species under similar pressures. "We were surprised to find that cells growing in chambers of all sorts of shapes gradually organized themselves into highly regular structures," Levchenko said. "The computational model helped explain why this was happening and how it might be used by the cells to increase chances of survival."

The microfluidic device, which was designed and fabricated in collaboration with Alex Groisman's laboratory at UCSD, allows the cells to flow freely into and out of the chambers. Test volumes in the chambers were in the nano- liter range, allowing visualization of single E. coli cells. Ann Stevens' laboratory at Virginia Tech helped to generate new strains of bacteria that permitted visualization of individual cells grown in a single layer.

Hojung Cho, a Johns Hopkins biomedical engineering doctoral student from Levchenko's lab and lead author of the journal article, captured on video the gradual self- organization and eventual construction of bacterial biofilms over a 24-hour period, using real-time microscopy techniques. The experiments were matched to modeling analysis developed in collaboration with Cho's colleagues at Lund. Images were analyzed using tools developed with the participation of Bruno Jedynak of the Johns Hopkins Center for Imaging Science.

Observation using microscopy revealed that the longer the packed cell population resided in the chambers, the more ordered the biofilm structure became, Levchenko said. Being highly packed in a tiny space can be very challenging for cells, so that any type of a strategy to help colony survival can be very important, he adds.

Levchenko also noted that rod-shaped E. coli that were too short or too long typically either did not organize well or did not avoid "stampede-like" blockages toward the exits. The shape of the confining space also strongly affected the cell organization in a colony, with highly disordered groups of cells found at sharp corners but not in the circular shaped microchambers.

Understanding how bacteria produce biofilms is important to researchers developing better ways to combat the diseases associated with them, Levchenko pointed out. For example, people who suffer from cystic fibrosis a genetic disorder that affects the mucus lining of the lungs are susceptible to a species of bacteria that colonizes the lungs. Patients choke on the colony's byproducts. Chronic urinary tract infections result from bacterial communities that develop inside human cells. And biofilms cause problems in tissues where catheters have been inserted or where sutures have been used.

"You can put a patient on antibiotics, and it may seem that the infection has disappeared. But in a few months, it reappears, and it is usually in an antibiotic-resistant form," Levchenko says. To explore possible treatments, Levchenko said, the microfluidic device could be used as a tool to rapidly and simultaneously screen different types of drugs for their ability to prevent biofilms.

Community
Email This Article
Comment On This Article

Related Links
Darwin Today At TerraDaily.com




Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
Monkeys rampage in Indian capital
New Delhi (AFP) Nov 13, 2007
Just weeks after the Indian capital's deputy mayor toppled to his death fighting off a pack of monkeys, the animals are back on the attack, sparking fresh concerns about the simian menace.

.
Get Our Free Newsletters Via Email
  



  • Emergency Response
  • Electronic Nose Could Detect Hazards
  • Court upholds jail term for Japanese architect
  • SkyPort Signs Contract With Cisco For Emergency Response Satellite Connectivity

  • World body warns over ocean 'fertilisation' to fix climate change
  • TAU Professor Finds Global Warming Is Melting Soft Coral
  • Groups oppose "ocean fertilisation" in Philippines
  • Global warming: Oceans could absorb far more CO2, says study

  • Earth Observation Essential For Geohazard Mitigation
  • SPOT - The World's First Satellite Messenger Now Shipping
  • Fujifilm Unveils GPS-Based Data Tape Tracker
  • Vacation Photos Create 3D Models Of World Landmarks

  • Baker Institute Study Shows Big Five Oil Companies Limit Exploration
  • Alternative fuels may boost pollution: report
  • Analysis: Poll finds energy tax support
  • Clean, Carbon-Neutral Hydrogen On The Horizon

  • Repellents Between Dusk And Bedtime Make Insecticide-Treated Bednets More Effective
  • Global Fund approves over 1 bln dlrs in new grants to fight disease
  • Bug-Zapper: A Dose Of Radiation May Help Knock Out Malaria
  • Failed AIDS vaccine may have increased infection risk

  • Together We Stand: Bacteria Organize To Survive Hostile Zones
  • Monkeys rampage in Indian capital
  • Changing Environment Organizes Genetic Structure
  • Time-Sharing Birds Key To Evolutionary Mystery

  • Britain the 'dustbin of Europe': official
  • Ignored and harassed, Indian scavengers demand better work life
  • UN demands deal to phase-out use of mercury
  • What Will Become Of The Sea Of Azov

  • China now has 18 million more young men than women
  • Human Ancestors: More Gatherers Than Hunters
  • One-child Chinese families prefer it that way
  • Key To False Memories Uncovered

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2007 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement