Tag Archives: single molecules

In one of nature’s innovations, a single cell smashes and rebuilds its own genome

Life can be so intricate and novel that even a single cell can pack a few surprises, according to a study led by Princeton University researchers.

The pond-dwelling, single-celled organism Oxytricha trifallax has the remarkable ability to break its own DNA into nearly a quarter-million pieces and rapidly reassemble those pieces when it’s time to mate, the researchers report in the journal Cell. The organism internally stores its genome as thousands of scrambled, encrypted gene pieces. Upon mating with another of its kind, the organism rummages through these jumbled genes and DNA segments to piece together more than 225,000 tiny strands of DNA. This all happens in about 60 hours. (more…)

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Bright Future for Protein Nanoprobes

Berkeley Lab Researchers Discover New Rules for Single-Particle Imaging with Light-Emitting Nanocrystals

The term a “brighter future” might be a cliché, but in the case of ultra-small probes for lighting up individual proteins, it is now most appropriate. Researchers at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered surprising new rules for creating ultra-bright light-emitting crystals that are less than 10 nanometers in diameter. These ultra-tiny but ultra-bright nanoprobes should be a big asset for biological imaging, especially deep-tissue optical imaging of neurons in the brain.

Working at the Molecular Foundry, a DOE national nanoscience center hosted at Berkeley Lab, a multidisciplinary team of researchers led by James Schuck and Bruce Cohen, both with Berkeley Lab’s Materials Sciences Division, used advanced single-particle characterization and theoretical modeling to study what are known as “upconverting nanoparticles” or UCNPs. Upconversion is the process by which a molecule absorbs two or more photons at a lower energy and emits them at higher energies. The research team determined that the rules governing the design of UCNP probes for ensembles of molecules do not apply to UCNP probes designed for single-molecules. (more…)

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