First-of-its-kind, data-driven machine learning model reveals in fine detail the pathway that solid-state reactions take.
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AI redesign helps enzymes evolve beyond natural limits
Researchers showed that AI-redesigned botulinum neurotoxin proteases provided more stable starting points for directed evolution, allowing enzymes to access beneficial mutations that were poorly tolerated in wild-type backgrounds. In BoNT/E models, the approach improved activity, evolvability, and specificity, including an ataxin-2-targeting variant with markedly reduced cleavage of the native SNAP25 substrate.
Broth Optical DensityBased Assessment for Phage Therapy: Turbidity Reduction, Antibacterial Virulence, and TimeKill
Phage therapy is the use of bacterial viruses, or bacteriophages, as antibacterial agents. It has been in use for over 100 years and is becoming increasingly common clinically. The first steps of phage therapy include identification of bacteria to be targeted and then obtaining phages with appropriate host ranges. This is followed by various approaches to in vitro phage characterization. Increasingly common for phage phenotypic characterization is the use of kinetic microtiter plate readers. They can both decrease workloads and increase throughput, especially relative to analyses that require plating on agar-based media. These colorimetric/turbidimetric/optical density approaches primarily assess phage-induced culture-wide bacterial lysis, in the shorter term, or instead the phage potential to suppress phage-resistance evolution over longer time frames. Considered here are methods relevant to phage characterization especially for phage-therapy purposes. Discussed are turbidity-reduction assays, determinations of phage antibacterial virulence, and related time-kill curve analysis. All are or can be optical density-based approaches to assessing phage-based bacterial reduction. Emphasis is placed on consideration of the utilities, limitations, and intersections of these similar methods. Emphasized is that the start of “Deviation”—where phage-treated culture turbidity diverges from phage-free controls—may represent a superior endpoint for such optical density-based bacterial-reduction protocols.
Chinese observatory identifies most powerful cosmic particle accelerator ever detected
Researchers working at the Large High Altitude Air Shower Observatory (LHAASO) in China’s Sichuan Province have discovered that the unique binary system Cygnus X-3, located in the constellation Cygnus, is the most powerful particle accelerator known to date. The findings were reported by Xinhua News Agency, a TV BRICS partner, citing the Institute of High Energy Physics of the Chinese Academy of Sciences.
Cygnus X-3 is a binary system consisting of either a black hole or a neutron star and a massive companion star. The compact object actively accretes material from the powerful stellar wind of its companion, accelerating particles to extremely high energies.
Scientists had previously believed that charged particles within the Milky Way could reach energies of around one petaelectronvolt (PeV). However, a detailed analysis of ultra-high-energy gamma-ray emissions enabled LHAASO researchers to determine that Cygnus X-3 is capable of accelerating cosmic rays to energies of at least 30 petaelectronvolts. The team also detected a periodic ultra-high-energy gamma-ray signal with a cycle of 4.8 hours and established that the particle acceleration region is located approximately three solar radii from the source of the radiation.
New radio burst method helps locate universe’s missing ordinary matter
Stars and galaxies make up much of the universe’s ordinary, observable matter. But for decades, scientists have wrestled with a cosmic conflict: There should be much more.
Physicists have good estimates of how much matter was present in the early universe. Shortly after the Big Bang, roughly 83% of all matter in the universe was composed of invisible dark matter, with ordinary matter making up the rest. And yet, these estimates exceed the amount of ordinary matter seen in stars and galaxies today. Where, then, did all the missing ordinary matter go?
Now MIT scientists, as part of the CHIME/FRB Collaboration, are using far-off radio signals to reveal missing matter in the vast space between galaxies. The team has developed a new method to search out missing matter by combining locations of galaxies with detections of fast radio bursts.
