Secretomes and Their Targets

By: Mariel Morales

Figure 1. A visual representation of the tree of life and the different classes of expressed open reading frames (ORF's) that are encoded in the sub-seafloor in meta-transcriptomes. The color coding represents different phylum and class levels.

          Although many may believe that marine sediment is only comprised of rock and soil particles, that is not the entire truth.  Products of secretion from both organic and inorganic elements, called secretomes, also exist in marine sediment. This residue is then recycled in order for there to be a long-term carbon storage for the cells to utilize as energy. In a study conducted by Orsi and colleagues, open reading frames (ORF's) were detected in order to find the presence of signal peptides in meta-transcriptomes in the seafloor. Signal peptides are used to signal protein transfer and meta-transcriptomes are the total RNA transcripts of the genes in a community.
          With all of those factors collected and inputted in several databases, the results of this study showed that when bacterial, archaeal, and fungal transcripts in the sub-seafloor meta-transcriptomes were compared, bacterial transcripts have a higher relative abundance of signal peptides while archaeal transcripts in have a higher abundance in regards to secretion (secretome).  The importance of this study was to identify the key microbial players in marine settlements and which microorganisms perform certain aspects of carbon recycling. 

Orsi WD, Richards AT, Francis RW (2017). Predicted microbial secretomes and the target substrates in marine sediment. Nature Mircrobiology 1: 1-8.