Curiosity Science

Scientists are reconstructing the oldest known star map, believed to be created by Hipparchus around 190–120 BCE. The map was hidden beneath later writings in a reused manuscript called Codex Climaci Rescriptus.

Researchers are scanning the parchment using a synchrotron X-ray accelerator at SLAC National Accelerator Laboratory. The scans detect chemical differences in ink, revealing Greek astronomical text beneath Syriac writing. Early results already show star coordinates and a reference to the constellation Aquarius.

This discovery could help scientists understand how ancient astronomers mapped the sky with remarkable accuracy using only naked-eye observations.

Source: ScienceAlert (David Nield, 8 March 2026); KQED interview with Victor Gysembergh.

Researchers at the Indian Institute of Science (IISC), working with collaborators from the Institute of Mathematical Sciences, have uncovered a key defense strategy used by Mycobacterium tuberculosis (Mtb): a protein called Lsr2 that detects and shuts down foreign DNA embedded in the bacterial genome.

Why this matters
Foreign DNA—often introduced by viruses—can disrupt essential bacterial processes. To stay viable and infectious, Mtb must identify and silence these risky genetic inserts.

What the team found

Selective binding: Lsr2 preferentially binds AT-rich DNA regions, which are typical of foreign genes, in an otherwise GC-rich Mtb genome.

Co-condensation: When many Lsr2 molecules accumulate, they stick together, forming protein–DNA condensates that compact the genome locally.

Gene silencing: This condensation physically blocks the transcription machinery, preventing harmful genes from being expressed.

How they proved it
Using single-molecule DNA imaging, advanced microscopy, and computer simulations, the team visualized how Lsr2 attaches to DNA and identified the protein regions responsible for DNA binding and protein–protein linking—both essential for condensate formation.

Implications for TB treatment
Because Lsr2 is crucial for Mtb infection, disrupting its condensation mechanism could leave the bacterium vulnerable. Targeting Lsr2’s binding or self-assembly domains offers a promising drug strategy against tuberculosis.

Reference
Gaur P. et al. Sequence-dependent co-condensation of Lsr2 with DNA elucidates the mechanism of genome compaction in Mycobacterium tuberculosis. Nucleic Acids Research (2026). DOI: 10.1093/nar/gkaf1428