Extracellular RNAs produced by a marine photosynthetic bacterium Rhodovulum sulfidophilum.

A marine photosynthetic bacterium Rhodovulum sulfidophilum secretes nucleic acids. Previously we have shown that these extracellular nucleic acids are a mixture of double-strand DNAs and single-strand RNAs. Here, we have more closely analyzed the RNA fraction of these extracellular nucleic acids. We determined the sequences of secreted RNAs. They have same sequences with parts of Rhodovulum sulfidophilum DSM 2351 16SrRNA or parts of ribosomal RNA operon of related species. Some of them were tRNAs. Interestingly, these tRNAs were mature tRNAs that had mature sizes, mature 5'-ends as well as 3'-CCA sequences. Additionally, we have found that these sequences were coded on genome, as expected. All of the secreted RNAs we detected may be parts of intracellular RNAs.