"We have used a synthetic biology approach to explicitly measure and test the adaptive advantage of programmed bacterial cell death in Escherichia coli," said Lingchong You, senior author of the study and an associate professor at the Department of Biomedical Engineering, Duke University, and the Duke Institute for Genome Sciences & Policy.
"The system is tunable which means that the extent of altruistic death in the bacterial population can be increased. We are therefore able to control the extent of programmed cell death as well as test the benefits of altruistic death under different conditions." The lead author of the study is Yu Tanouchi, a graduate student in the Department of Biomedical Engineering. Anand Pai and Nicolas Buchler also contributed to the work.
Scientists have known for some time that programmed cell death can be linked to the response of bacteria to stressful conditions, for example starvation of amino acids or the presence of competitor molecules. However, it is not clear why cells should choose to die under such conditions since it gives them no immediate advantages. Some researchers have suggested that programmed cell death allows cells to provide benefits to their survivors but until now it has been difficult to test this directly in experiments.
The researchers used synthetic biology procedures to engineer Escherichia coli in such a way that the bacterial cells are capable of suicidal behavior and promoting the good of the bacterial population. To do so they introduced a gene circuit, which consists of two modules, into the bacteria. If the "suicide module" is active it leads to the rupture and death of some bacterial cells when they are challenged with the antibiotic 6-aminopenicillanic acid. If the "public good" module is expressed, a modified form of the enzyme beta-lactamase is produced, which protects surviving cells from rupture or lysis by breaking down the antibiotic. This protection only occurs when the enzyme is released from inside the bacterial cells that make the ultimate sacrifice and die after rupture.
"Our results clearly demonstrate that it is possible to have conditions where the death of some bacteria confers an advantage for the overall population of bacteria," remarked You. "The optimal death rate for the bacterial population emerges after sufficient time has passed and is clearly visible in our system."The scientists were also able to provide a possible explanation for the "Eagle effect", an unexpected phenomenon where bacteria appear to grow better when treated with higher antibiotic concentrations. "Overall our results fill in a conceptual gap in understanding the evolutionary dynamics of programmed bacterial death during stress and have implications for designing intervention strategies for effective treatment of bacterial infections with antibiotics," concluded You.
Media ContactsBarry Whyte
EMBO is an organization of 1500 leading life scientist members that fosters new generations of researchers to produce world-class scientific results. EMBO helps young scientists to advance their research, promote their international reputations and ensure their mobility. Courses, workshops, conferences and scientific journals disseminate the latest research and offer training in cutting-edge techniques to maintain high standards of excellence in research practice. EMBO helps to shape science and research policy by seeking input and feedback from our community and by following closely the trends in science in Europe.
Barry Whyte | EurekAlert!
New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences
The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences