Branched-chain amino acid assimilation promotes mixotrophy of ammonia-oxidizing archaeal sponge symbionts

Correlative CARD-FISH and NanoSIMS imaging data accompanying the article “Branched‑chain amino acid assimilation promotes mixotrophy of ammonia‑oxidizing archaeal sponge symbionts” (Glasl & Kitzinger et al.). Sponge symbionts were visualized by catalyzed reporter deposition fluorescence in situ hybridization (CARD‑FISH), and isotopic enrichment in sponge tissue thin sections (host and symbiont biomass) was quantified by NanoSIMS after incubations with stable‑isotope–labeled substrates: 13C‑NaHCO3 or an equimolar mixture of 13C/15N‑labeled branched‑chain amino acids (valine, leucine, isoleucine). A non‑incubated section at natural isotopic abundance is included as a baseline control.