New imaging tech lets scientists 'paint' a target in a living subject and watch it work -- with unprecedented sensitivity and precision
Scientists at USC have developed a new microscopy technology that allows them to view single molecules in living animals at higher-than-ever resolution.
Dubbed "Complementation Activated Light Microscopy" (CALM), the new technology allows imaging resolutions that are an order of magnitude finer than conventional optical microscopy, providing new insights into the behavior of biomolecules at the nanometer scale.
In a paper published on Sept. 18 by Nature Communications, the researchers behind CALM used it to study dystrophin – a key structural protein of muscle cells – in Caenorhabditis elegans worms used to model Duchenne muscular dystrophy.
Duchenne muscular dystrophy is the most severe and most common form of the degenerative disease.
The researchers showed that dystrophin was responsible for regulating tiny molecular fluctuations in calcium channels while muscles are in use. The discovery suggests that a lack of functional dystrophin alters the dynamics of ion channels – helping to cause the defective mechanical responses and the calcium imbalance that impair normal muscle activity in patients with muscular dystrophy.
Ten Times the Precision of Optical Microscopy
CALM works by splitting a green fluorescent protein from a jellyfish into two fragments that fit together like puzzle pieces. One fragment is engineered to be expressed in an animal test subject while the other fragment is injected into the animal's circulatory system.
When they meet, the fragments unite and start emitting fluorescent light that can be detected with incredible accuracy, offering imaging precisions of around 20 nanometers. Conventional optical microscopy of living tissues can only achieve a 200 nanometer resolution at best. For scale, a sheet of paper is 100,000 nanometers thick.
"Now, for the first time, we can explore the basic principles of homeostatic controls and the molecular basis of diseases at the nanometer scale directly in intact animal models," said Fabien Pinaud, assistant professor at the USC Dornsife College of Letters, Arts and Sciences and lead researcher on the project.
Pinaud collaborated with scientists from the University Claude Bernard Lyon in France and the University of Würzburg in Germany.
Building the Tools for Tomorrow's Research
The new technology lies at the heart of the convergence of science and engineering at USC, where researchers from both fields collaborate to create the tools that make scientific and medical breakthroughs possible.
"There are trillions of proteins at work on an infinitely small scale at every moment in an animal's body. The ability to detect individual protein copies in their native tissue environment allows us to reveal their functional organization and their nanoscale molecular behaviors despite this astronomical complexity," Pinaud said.
Next, Pinaud and his colleagues will focus on engineering other colors of split-fluorescent proteins to image the dynamics of individual ion channels at neuromuscular synapses within live worms.
"It so happens that the same calcium channels we studied in muscles also associate with nanometer-sized membrane domains at synapses where they modulate neuronal transmissions in both normal and disease conditions," Pinaud said. Using multi-color CALM, his team and collaborators will probe how these tiny active zones of neurons are assembled and how they influence the function of calcium channels during neuron activation.
This research was funded by USC startup funds and the computational work was supported by the USC Center for High-Performance Computing and Communications.
Robert Perkins | Eurek Alert!
Correcting presbyopia with the laser
06.02.2019 | Laser Zentrum Hannover e.V.
New technology gives unprecedented look inside capillaries
28.01.2019 | Northwestern University
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...
Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.
DNA is not only a popular research topic because it contains the blueprint for life – it can also be used to produce tiny components for technical applications.
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
19.02.2019 | Physics and Astronomy
19.02.2019 | Information Technology
19.02.2019 | Physics and Astronomy