Natural sunscreen compound identified in hot springs bacteria

Researchers from Meijo University found a new UV‑blocking molecule, GlcHMS326, in thermophilic cyanobacteria from a Thai hot spring; it is produced under UV and high‑salt stress and shows strong antioxidant activity.

Microbiologists at Meijo University have identified a previously unknown ultraviolet‑absorbing compound made by heat‑loving cyanobacteria collected from a hot spring in Thailand. The work examined bacterial strains isolated from the Bo Khlueng hot spring in Ratchaburi Province and focused on how organisms adapt to intense sunlight and salty conditions. The compound, named β‑glucose‑bound hydroxy mycosporine‑sarcosine (GlcHMS326), appears only when the bacteria experience UV‑A and UV‑B exposure combined with high salt. The study highlights a distinct biosynthetic route for this molecule that has not been reported before. Key findings: - The research team isolated eight thermophilic cyanobacterial strains and observed GlcHMS326 production in a Gloeocapsa species under UV and salt stress. - GlcHMS326 is β‑glucose‑bound hydroxy mycosporine‑sarcosine and is produced in response to UV‑A, UV‑B, and high salinity rather than heat. - The molecule carries three chemical modifications — glycosylation, hydroxylation, and methylation — not previously reported in cyanobacterial MAAs. - Genetic analysis found a unique set of genes in the producer strain that are associated with these modifications and the compound's biosynthesis. - Laboratory assays reported stronger free‑radical scavenging (antioxidant) activity for GlcHMS326 compared with more common mycosporine‑like amino acids. Summary: The finding identifies a naturally produced UV‑filter with notable antioxidant properties and documents a unique biosynthetic pathway in thermophilic cyanobacteria, which the authors note could inform industrial biotechnology related to natural UV‑filter ingredients. Undetermined at this time.