(Press-News.org) Irvine, Calif., Nov. 13, 2012 — UC Irvine biologists have discovered that fats within cells store a class of proteins with potent antibacterial activity, revealing a previously unknown type of immune system response that targets and kills bacterial infections.
Steven Gross, UCI professor of developmental & cell biology, and colleagues identified this novel intercellular role of histone proteins in fruit flies, and it could herald a new approach to fighting bacterial growth within cells. The study appears today in eLife, a new peer-reviewed, open-access journal supported by the Howard Hughes Medical Institute, the Max Planck Society and the Wellcome Trust.
"We found that these histone proteins have pan-antibacterial abilities and can have a wide-ranging effect," Gross said. "If we can discover how to manipulate the system to increase histone levels, we may one day have a new way to treat patients with bad bacterial infections."
Histones exist in large numbers in most animal cells; their primary job is to help DNA strands fold into compact and robust structures inside the nucleus. Gross said there is some evidence that histones secreted from cells protect against bacteria living outside cells. However, many bacteria enter cells, where they can avoid the immune system and continue replicating.
In principle, Gross said, histones could protect cells against such bacteria from the inside, but for many years this was thought unlikely because most histones are bound to DNA strands in the cell nucleus, whereas bacteria multiply in the cellular fluid outside the nucleus, called cytosol. Additionally, free histones can be extremely damaging to cells, so most species have developed mechanisms to detect and degrade free histones in the cytosol.
In their study, Gross and colleagues demonstrate that histones bound to lipid (fat) droplets can protect cells against bacteria without causing any of the harm normally associated with the presence of free histones. In experiments with lipid droplets purified from Drosophila fruit fly embryos, they show that lipid-bound histones can be released to kill bacteria.
The researchers injected similar numbers of bacteria into Drosophila embryos that contained lipid-bound histones and into embryos genetically modified to not contain them. They discovered that the histone-deficient flies were 14 times more likely to die of bacterial infections. Similar results were found in experiments on adult flies. Additional evidence suggested that histones might also protect mice against bacteria.
"Because numerous studies have now identified histones on lipid droplets in many different cells – from humans as well as mice and flies – it seems likely that this system may be quite general," Gross said.
###Preetha Anand, Silvia Cermelli, Robilyn Sigua and Lan Huang of UCI; Zhihuan Li and Michael Welte of New York's University of Rochester; Adam Kassan, Marta Bosch and Albert Pol of the August Pi i Sunyer Biomedical Research Institute in Barcelona, Spain; and Andre Ouellette of USC contributed to the study (Anand et al. eLife 2012;1:e00003. DOI: 10.7554/eLife.00003), which was supported by the National Institutes of Health (grants GM64624 and GM64687), the National Science Foundation and the Spanish Ministry of Science & Innovation.
About the University of California, Irvine: Founded in 1965, UCI is a top-ranked university dedicated to research, scholarship and community service. Led by Chancellor Michael Drake since 2005, UCI is among the most dynamic campuses in the University of California system, with nearly 28,000 undergraduate and graduate students, 1,100 faculty and 9,000 staff. Orange County's second-largest employer, UCI contributes an annual economic impact of $4 billion. For more UCI news, visit www.today.uci.edu.
News Radio: UCI maintains on campus an ISDN line for conducting interviews with its faculty and experts. Use of this line is available for a fee to radio news programs/stations that wish to interview UCI faculty and experts. Use of the ISDN line is subject to availability and approval by the university.
Contact:
Tom Vasich
949-824-6455
tmvasich@uci.edu
UCI maintains an online directory of faculty available as experts to the media. To access, visit www.today.uci.edu/experts.
For UCI breaking news, visit www.zotwire.uci.edu.
CINCINNATI—People living near a former uranium ore processing facility in Ohio are experiencing a higher than average rate of lupus, according a new study conducted by scientists at the University of Cincinnati and Cincinnati Children's Hospital Medical Center.
Lupus is a chronic inflammatory disease that can affect the skin, joints, kidneys, lungs, nervous system and other organs of the body. The underlying causes of lupus are unknown, but it is usually more common in women of child-bearing age.
For this new study, a collaborative team of UC and Cincinnati Children's ...
Implantable defibrillators currently on the market apply between 600 and 900 volts to the heart, almost 10 times the voltage from an electric outlet, says Ajit H. Janardhan, MD, PhD, a cardiac electrophysiology fellow at the Washington University's School of Medicine.
After being shocked, he says, some patients get post-traumatic stress disorder. Patients may even go so far as to ask their physicians to remove the defibrillator, even though they understand that the device has saved their lives.
The huge shocks are not only unbearably painful, they damage the heart muscle ...
Languages are highly complex systems and yet most children seem to acquire language easily, even in the absence of formal instruction. New research on young children's use of British Sign Language (BSL) sheds light on one of the mechanisms - iconicity - that may endow children with this amazing ability.
For spoken and written language, the arbitrary relationship between a word's form – how it sounds or how it looks on paper – and its meaning is a particularly challenging feature of language acquisition. But one of the first things people notice about sign languages is ...
This press release is available in Spanish and French.
Monterrey, 13 November 2012—Today, the Nuevo León state ministry of sustainable development, with support from the Commission for Environmental Cooperation (CEC), launched a revamped air quality information management system in Monterrey, Mexico, using AirNow-International.
This CEC initiative, developed in coordination with Canadian, Mexican and US government agencies, is laying the foundation for improved ways to inform citizens around the country about air quality in their communities with real-time data that ...
On Nov. 13, 2012, the sun emitted a mid-level solar flare, peaking at 9:04 p.m. EST.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where Global Positioning System (GPS) and communications signals travel. This disrupts the radio signals for as long as the flare is ongoing, anywhere from minutes to hours.
This flare is classified as an M6 flare. M-class flares are the weakest flares ...
On Nov. 13, 2012, certain parts of Earth will experience a total solar eclipse, which, like all eclipses, will only be visible when you are aligned in a straight line with the moon and the sun. In this case the eclipse will only be seen from a narrow corridor in the southern hemisphere that is mostly over the ocean but also cuts across the northern tip of Australia. The JAXA/NASA Hinode mission will experience a partial eclipse of the sun near the same time as the observers in Australia. Hinode will coordinate its observations with those from the ground, before, during, ...
On the night of Aug. 5, 2010, as residents slept, water began rushing through Leh, an Indian town in a high desert valley in the Himalayas.
Average total rainfall in the area for August is about a half-inch. During this 24-hour period more than 8 inches fell, causing severe damage and leaving 193 dead, hundreds missing and thousands homeless.
"Flash flooding events don't happen often but when they do they are some of the scariest, most dangerous and quickest natural disasters that can happen," said Kristen Rasmussen, a University of Washington graduate student in ...
RIVERSIDE, Calif. (www.ucr.edu) — Two professors at the University of California, Riverside Bourns College of Engineering have developed a new method that doubles the efficiency of wireless networks and could have a large impact on the mobile Internet and wireless industries.
Efficiency of wireless networks is key because there is a limited amount of spectrum to transmit voice, text and Internet services, such as streaming video and music. And when spectrum does become available it can fetch billions of dollars at auction.
The "spectrum crunch" is quickly being accelerated ...
Women with migraines did not appear to experience a decline in cognitive ability over time compared to those who didn't have them, according to a nine-year follow up study funded by the National Institutes of Health.
The study also showed that women with migraine had a higher likelihood of having brain changes that appeared as bright spots on magnetic resonance imaging (MRI), a type of imaging commonly used to evaluate tissues of the body.
"The fact that there is no evidence of cognitive loss among these women is good news," said Linda Porter, Ph.D., pain health science ...
TORONTO, Nov. 13, 2012—A first-of-its-kind program at St. Michael's Hospital lowers risk of delirium in elderly patients admitted for trauma and decreases the likelihood they will be discharged to a long-term care facility.
The Geriatric Trauma Consultation Service is a program where every patient over 60 admitted to the trauma service is seen by a member of the geriatric team within 72 hours.
This is a big change from previous practice, where only 4 per cent of elderly patients admitted to trauma were seen by a geriatric team member during their stay in hospital.
"Older ...
