Justin Gallivan, PhD, assistant professor of chemistry, and graduate student Shana Topp successfully reprogrammed E. coli's chemo-navigational system to detect, follow and precisely localize to specific chemical signals. In doing so, the scientists exploited E. coli's natural chemotaxis, a microbe's ability to move toward specific chemicals in its environment.
"Equipping bacteria with a way to degrade pollutants, synthesize and release therapeutics, or transport chemicals with an ability to localize to a specific chemical signal would open new frontiers in environmental cleanup, drug delivery and synthetic biology," says Dr. Gallivan.
The researchers equipped E. coli with a "riboswitch," a segment of RNA that changes shape when bound to certain small target molecules, which can then turn genes on or off. Dr. Gallivan and Topp believe that the riboswitch can be used to equip other types of self-propelled bacteria with "chemo-navigation" systems to move them toward desired targets.
Chemotactic bacteria navigate chemical environments by coupling their information-processing capabilities to powerful, tiny molecular motors that propel the cells forward.
Researchers have long envisioned reprogramming bacteria so that microbes capable of synthesizing an anti-cancer drug, for instance, can be used to target diseased cells while sparing healthy cells of side effects. Likewise, scientists are researching ways to use bacteria to clean up oil spills or remove other pollutants from soil, water and wastewater.
"This new ability to equip motile bacteria with a precise and tunable chemo-navigation system will greatly enhance the impressive arsenal of natural and engineered cell behaviors," says Dr. Gallivan.
Holly Korschun | EurekAlert!
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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22.09.2017 | Physics and Astronomy