Everything OLD is new again: How structural, functional, and bioinformatic advances have redefined a neglected nuclease family.

Overcoming lysogenization defect (OLD) proteins are a conserved family of ATP-powered nucleases that function in anti-phage defense. Recent bioinformatic, genetic, and crystallographic studies have yielded new insights into the structure, function, and evolution of these enzymes. Here we review these developments and propose a new classification scheme to categorize OLD homologs that relies on gene neighborhoods, biochemical properties, domain organization, and catalytic machinery.

Recombineering: Genetic Engineering in Escherichia coli Using Homologous Recombination.

The bacterial chromosome and bacterial plasmids can be engineered in vivo by homologous recombination using either PCR products or synthetic double-stranded DNA (dsDNA) or single-stranded DNA as substrates. Multiple linear dsDNA molecules can be assembled into an intact plasmid. The technology of recombineering is possible because bacteriophage-encoded recombination proteins efficiently recombine sequences with homologies as short as 35 to 50 bases.

Tracking the 2022 Hunga Tonga-Hunga Ha'apai Aerosol Cloud in the Upper and Middle Stratosphere Using Space-Based Observations.

On 15 January 2022, the submarine Hunga Tonga volcanic eruption lofted materials high into the upper stratosphere, reaching a record-breaking altitude of ∼58 km, unprecedented in the satellite observations era. Within two weeks, the bulk of the injected material circulated the globe between 20-30 km altitude, as observed by satellite instruments. We estimate that the stratospheric aerosol optical depth (sAOD) is the largest since the Pinatubo eruption and is at least twice as great as the sAOD after the 2015 Calbubo eruption despite the similar SO injection from that eruption.