Compounds in cranberry juice have the ability to change E. coli bacteria, a class of microorganisms responsible for a host of human illnesses (everything from kidney infections to gastroenteritis to tooth decay), in ways that render them unable to initiate an infection. The results of this new research by scientists at Worcester Polytechnic Institute (WPI) suggest that the cranberry may provide an alternative to antibiotics, particularly for combating E. coli bacteria that have become resistant to conventional treatment.
The new findings, which will be presented on Sunday, Sept. 10, at the annual meeting of the American Chemical Society in San Francisco, for the first time begin to paint a detailed picture of the biochemical mechanisms that may underlie a number of beneficial health effects of cranberry juice that have been reported in other studies over the years.
Many of those studies have focused on the ability of cranberry juice to prevent urinary tract infections (UTIs), which each year affect eight million people–mostly women, the elderly, and infants--resulting in $1.6 billion in health care costs. Until now, scientists have not understood exactly how cranberry juice prevents UTIs and other bacterial infections, though they have suspected that compounds in the juice somehow prevent bacteria from adhering to the lining of the urinary tract. The new findings reveal how the compounds interfere with adhesion at the molecular level.
The new results will be incorporated in two presentations during a session that runs from 8:30 to 11:40 a.m. in the Windsor Room of the Sir Francis Drake Hotel.
The research, by Terri Camesano, associate professor of chemical engineering at WPI, and graduate students Yatao Liu and Paola Pinzon-Arango, and funded, in part, by the National Science Foundation, shows that a group of tannins (called proanthocyanidins) found primarily in cranberries affect E. coli in three devastating ways, all of which prevent the bacteria from adhering to cells in the body, a necessary first step in all infections:
They change the shape of the bacteria from rods to spheres.
They alter their cell membranes.
They make it difficult for bacteria to make contact with cells, or from latching on to them should they get close enough.
For most of these effects, the impact on bacteria was stronger the higher the concentration of either cranberry juice or the tannins, suggesting that whole cranberry products and juice that has not been highly diluted may have the greatest health effects.
The new results build on previously published work, in which Camesano and her team showed that cranberry juice causes tiny tendrils (known as fimbriae) on the surface of the type of E. coli bacteria responsible for the most serious types of UTIs to become compressed. Since the fimbriae make it possible for the bacteria to bind tightly to the lining of the urinary tract, the change in shape greatly reduces the ability of the bacteria to stay put long enough to initiate an infection.
More recently, Camesano and Liu have shown that chemical changes caused by cranberry juice also create an energy barrier that keeps the bacteria from getting close to the urinary tract lining in the first place.
New work by Camesano and Pinzon-Arango shows that cranberry juice can transform E. coli bacteria in even more radical ways. The researchers grew E. coli over extended periods in solutions containing various concentrations of either cranberry juice or tannins. Over time, the normally rod-shaped bacteria became spherical--a transformation that has never before been observed in E. coli.
Remarkably, the E. coli bacteria, all of which fall into a class called gram-negative bacteria, began behaving like gram-positive bacteria--another never-before-seen phenomenon. Since gram-negative and gram-positive bacteria differ primarily in the structure of their cell membranes, the results suggest that the tannins in cranberry juice can alter the membranes of E. coli.
A final, more preliminary result that will be presented at the ACS meeting suggests that E. coli bacteria exposed to cranberry juice appear to lose the ability to secrete indole, a molecule involved in a form of bacterial communication called quorum sensing. E. coli use quorum sensing to determine when there are enough bacteria present at a certain location to initiate a successful infection.
"We are beginning to get a picture of cranberry juice and, in particular, the tannins found in cranberries as, potentially potent antibacterial agents," Camesano says. "These results are surprising and intriguing, particularly given the increasing concern about the growing resistance of certain disease-causing bacteria to antibiotics."
Michael Dorsey | EurekAlert!
Progress in Super-Resolution Microscopy
17.12.2018 | Julius-Maximilians-Universität Würzburg
Communication between neural networks
17.12.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
17.12.2018 | Studies and Analyses
17.12.2018 | Life Sciences
17.12.2018 | Power and Electrical Engineering