Fig. 5.

—Chemical structures, LC-ESI-QTOF targeted MS/MS parameters and respective characteristic MS/MS spectra for both synthetic and bee larval 2′-O-methyl modified ribonucleosides. Ribonucleosides were generated by treatment with ribonuclease T2 of synthetic piRNAs and piRNA-enriched larval samples. The blue diamond in each MS/MS spectrum indicates the position of the targeted precursor ion. For all four modified bases, greater count levels were observed in drones relative to both queens and workers. For 2′-O-methyladenosine and 2′-O-methylguanosine, greater count levels were seen in queens relative to workers, while for 2′-O-methylcytidine and 2′-O-methyluridine, similar count levels were observed in both female castes.